Causality and climate

Guest post by Antonis Christofides, Demetris Koutsoyiannis, Christian Onof and Zbigniew W. Kundzewicz

On the chicken-and-egg problem of CO2 and temperature.

Bare facts vs. mechanism

A car is travelling at 80 km/h, and a ray of light is travelling parallel to the car, in the same direction. Its speed relative to the Earth is 300,000 km/s. What is its speed relative to the car? Today we know that the answer “300,000 km/s minus 80 km/h” is wrong. But in 1887, people thought that it was self-evident and undisputable—after all, it’s basic logic and simple arithmetic. At that time, physicists Michelson and Morley had devised a method with sufficient accuracy to measure the small differences in the speed of light, and in an effort to discover details about its movement, they conducted one of the most famous experiments in the history of science. The results were baffling. The speed of light was constant in all directions—the direction of the Earth’s movement, the opposite direction, and the perpendicular direction. There was no explanation for that—it defied all logic.

However, we have to look at the bare facts, regardless how impossible they seem. Michelson and Morley did not feel compelled to provide an alternative theory of light, or of anything. They concluded that their results “refute Fresnel’s explanation of aberration” and that Lorentz’s theory “also fails.” Had they written “we have no idea what’s going on” it would have been the same. Making their negative results public opened the road to further research. It was a long road, and it took almost twenty years of work by distinguished scientists before arriving at the theory of relativity.

It goes without saying that this is hardly the first or the last mystery in the history of science. One that is still unsolved is the changing mass of the International Prototype of the Kilogram. Until a few years ago, the kilogram was defined as the mass of a platinum-iridium object stored in the International Bureau of Weights and Measures in Paris. It has been found that its mass changes over time by something like 0.000005% per century, and no-one knows why exactly. That no-one knows the mechanism does not alter the fact that the mass does change.

How a clear case of causality can become a noisy mess

Imagine a beach being hit by small waves. Once in a while, a series of noticeably larger waves arrive. There’s a port 10 km further, and ships are departing from it. We might notice that the departures of the ships are correlated to the instances of larger waves, and suspect that there could be a causal relationship.

In reality, in this case we understand the mechanism through which the ships cause the waves; but if we assume we don’t, here is how we might try to investigate: we might draw a chart like the following, where the horizontal axis is time, the orange line shows ship departures (the vertical axis showing the size of the ship) and the blue line shows sea level. If every departure was reliably followed by a temporary increase in wave height, we could conclude that the departures of the ships potentially cause the increase in wave height, especially if we noticed that the size of the ship is correlated to the size of the increase in wave height.

We say “potentially” because we can never be certain about causation. It could be that the departures and the waves both have a common cause. Even if someone was shot in the head, we can’t be certain it was the bullet that killed him—he might have suffered a stroke just before the bullet entered his brain (Agatha Christie’s Poirot has resolved several mysteries of similar type). So we can hardly be 100% certain that X causes Y. One thing is clear, however: the waves do not cause the ships to depart. The reason is that first the ship departs and later the waves hit the beach. The effect cannot precede the cause.

Even in this simple case where there’s an impulse (the departing ship) followed by a response, things can quickly get complicated. Ships could be going in many different directions, and the response would not always appear in an equal time interval after the impulse. For some impulses the response could be totally absent (e.g. for ships that depart in a direction away from the beach). The interval between departures could be smaller than the time it takes for the response to arrive, and the intertwining of impulses and responses could be confusing. Sometimes responses might appear out of the blue, without impulse (for example, there could be arriving ships that cause that, which we might not have taken into account). It might not be as easy to distinguish the wave response from the other waves if the sea is rough. Add all these factors together, and the blue line could be a big noisy mess.

And in a real world example, like in the question of whether CO₂ concentration affects the temperature, both lines can be a big noisy mess.

Investigating potential causes

So here is the question: given two processes, how can we determine if one is a potential cause of the other? We deal with this question in two papers we published last year in the Proceedings of the Royal Society A (PRSA): Revisiting causality using stochastics: 1. Theory (preprint); 2. Applications (preprint). We reviewed existing theories of causation, notably probabilistic theories, and found that all of them have considerable limitations.

For example, Granger’s theory and statistical test have already been known to be identifying correlation (for making predictions), not causation, despite the popular term “Granger causality”. What is more, they ignore the fact that processes exhibit dependence in time. Hence, formally testing hypotheses in geophysics by such tests can be inaccurate by orders of magnitude due to that dependence.

As another example, Pearl’s theories make use of causal graphs, in which the possible direction of causation is assumed to be known a priori. This implies that we already have a way of identifying causes. Moreover, insofar as those theories assume, in their use of the chain rule for conditional probabilities, that the causality links in the causal graphs are of Markovian type, their application to complex systems is problematic.

Another misconception in some of earlier studies is the aspiration that by using a statistical concept other than the correlation coefficient (e.g. a measure of information) we can detect genuine causality.

Having identified the weaknesses in existing theories and methodologies, we proceeded to develop a new method to study the question whether process X is a potential cause of process Y, or the other way round. This has several key characteristics which distinguish it from existing methods.

• Our framework is for open systems (in particular, geophysical systems), in which:
• External influences cannot be controlled or excluded.
• Only a single realization is possible—repeatability of a geophysical process is infeasible.
• Our framework is not formulated on the basis of events, but of stochastic processes. In these:
• Time runs continuously. It is not a sequence of discrete time instances.
• There is dependence in time.
• It is understood that only necessary conditions of causality can be investigated using stochastics (or other computational tools and theories)—not sufficient ones. The usefulness of this, less ambitious, objective of seeking necessary conditions lies in their ability:
• To falsify an assumed causality.
• To add statistical evidence, in an inductive context, for potential causality and its direction.

The only “hard” requirement kept from previous studies is the temporal precedence of the cause over the effect. Sometimes it can happen that causation goes both ways; for example, hens lay eggs and eggs hatch into hens (and it was Plutarch who first used the metaphor of hen and egg for this problem). Conveniently, we call such systems “potentially hen-or-egg causal”. Our method also identifies these, and also determines in these cases which of the two directions is dominant.

To deal with dependence in time, often manifested in high autocorrelation of the processes, we proposed the differencing of the time series, which substantially decreases the autocorrelation. In other words, instead of investigating the processes X and Y and find spurious results (as has been the case in several earlier studies), we study the changes thereof in time, ΔX and ΔY.

A final prominent characteristic of our method is its simplicity. It uses the data per se, rather than involved transformations thereof such as the cross- and auto-correlation functions or their Fourier transforms —the power spectra and cross-spectra. The results are thus more reliable and easier to interpret.

Atmospheric temperature and CO₂ concentration

In our PRSA papers we implemented our method in several case studies, such as rainfall-runoff and El Niño-temperature. One of the case studies was CO₂ concentration and temperature, and this one gave strong indications that temperature is potentially the cause and CO₂ the effect, while the opposite causality direction can be excluded as violating the necessary condition of time precedence.

However, the scope of these two papers was to formulate a general methodology for the detection of causality rather than to study a specific system in detail, and the case studies were brief. With regard to the relationship between temperature and CO₂ concentration, we hadn’t gone into details as to the effect of seasonality and time scale, or the exploration of many sources of data. So in our latest paper, published a week ago in Sci (“On hens, eggs, temperatures and CO2: Causal links in Earth’s atmosphere”), we studied the issue in detail. We used CO₂ data from Mauna Loa and from the South Pole, and temperature data from various sources (our published results are for the NCAR/NCEP reanalysis, but in the previous papers we used satellite data too). We used both historical data and the outputs of climatic models. We examined time scales ranging from months to decades.

The results are clear: changes in CO₂ concentration cannot be a cause of temperature changes. On the contrary, temperature change is a potential cause of CO₂ change on all time scales. As we conclude in the paper, “All evidence resulting from the analyses of the longest available modern time series of atmospheric concentration of [CO₂] at Mauna Loa, Hawaii, along with that of globally averaged  T, suggests a unidirectional, potentially causal link with  T as the cause and [CO₂] as the effect. This direction of causality holds for the entire period covered by the observations (more than 60 years).”

The math is a bit too complicated to present here. However all three papers have been reviewed extensively by referees and editors (notice in the last paper that four editors were involved as seen on the front page of the paper). The results in the earlier papers were criticized, formally by a commentary in the same journal and informally in blogs and social media. Some concerns expressed by critics, such as about lengths of time series, effect of seasonality, effect of timescale, are dealt with in this new paper. No-one has however developed any critique of the methodology.

In addition, the following graphic (taken from the graphical abstract of the paper and inserted here as a quiz) aims to make things even clearer. In this we plot the time series on the annual scale to avoid too many points. Hopefully even the annual scale of this graph (in contrast to the monthly scale we used in our detailed results) suffices to suggest that there is very little doubt as to the potential causality direction.

Do climate models faithfully represent the causality direction found in the real world data? This question is also investigated in our new paper. The reply is clearly negative: the models suggest a causality direction opposite to the one found when the real measurements are used. Thus, our methodology defines a type of data analysis that, regardless of the claims we infer about the detection of causality per se, assesses modelling performance by comparing observational data with model results. In this, it contributes in studying an epistemological problem and, in particular, it casts doubt over the widespread claims that “in silico experimentation” with climate models is the only option we have and that this can be justified by the (insufficiently validated) assumption of an “increasing realism of climate system models”.

One might think that the potential causality direction we determined is counterintuitive in the light of the well-known greenhouse effect, and that the effect of temperature on CO₂ concentration would be subtle. But no, it is quite pronounced. In fact, human emissions are only 4% of the total, natural emissions dominate, and the increase of the latter because of temperature rise is more than three times the human emissions. This it is visible in a graph we included in an Appendix to the paper.

Figure A1 from Koutsoyiannis et al. (2023): Annual carbon balance in the Earth’s atmosphere in Gt C/year, based on the IPCC estimates. The balance of 5.1 Gt C/year is the annual accumulation of carbon (in the form of CO2) in the atmosphere.

Of course, several questions remain. Why does the temperature increase? And why does the temperature rise potentially cause an increase in CO₂ concentration? Is the temperature change a real cause of the CO₂ concentration change, or could they both be the result of some further causal factor? It’s not hard to speculate. Yet we briefly investigate quantitatively possible mechanisms for these causal relationship in the appendices to the paper. However, if we stick to the facts, two things are clear: (i) changes in CO₂ concentration have not been warming the planet; (ii) climate models do not reflect what the observational data tell us on this issue.

JC comment:  I find this analysis to be very interesting.  The global carbon cycle is definitely “unsettled science.”  I think what this paper shows is that CO2 is an internal feedback in the climate system, not a forcing (I think that Granger causality would reveal this?). Yes, this all depends on how we define the system, and humans and their emissions are currently acting outside of the system in most climate models and are considered as an external forcing.  Again, as emphasized in the paper, human emissions are small fraction of natural emissions so this issue of internal versus external isn’t straightforward.  By analogy, in the 1970’s climate models specified cloud cover, and hence clouds acted as an external forcing.  However, clouds vary in response to the climate, and now with interactive clouds, clouds are now correctly regarded as a feedback and not a forcing.

References

1. Koutsoyiannis, C. Onof, A. Christofides, and Z. W. Kundzewicz, Revisiting causality using stochastics: 1.Theory, Proceedings of The Royal Society A, 478 (2261), 20210835, doi:10.1098/rspa.2021.0835, 2022.
2. Koutsoyiannis, C. Onof, A. Christofides, and Z. W. Kundzewicz, Revisiting causality using stochastics: 2. Applications, Proceedings of The Royal Society A, 478 (2261), 20210836, doi:10.1098/rspa.2021.0836, 2022.

D. Koutsoyiannis, C. Onof, Z. W. Kundzewicz, and A. Christofides, On hens, eggs, temperatures and CO₂: Causal links in Earth’s atmosphere, Sci,

1,001 responses to “Causality and climate”

1. Curious George

Is a chicken a “forcing” or a “feedback” of an egg?

• Good question… Difficult answer…. So, we preferred different phraseology (and different foundation of our math) as you may see in the paper.

• Argumentum ad ignorantiam is a bad opening move. You aver that the standard Kilo in Paris

” has been found that its mass changes over time by something like 0.000005% per century, and no-one knows why exactly.”

The loss is due to two mechanisms, one physical and one chemical. Despite care in handling, the platinum -iridium cylinder is not immune to mechanical and atmospheric erosion. At the time of the metric standards manufacture, zone refined high purity ( 99.9999+%) platinum and iridium did not yet exist.

The Victorian era mass cylinders and standard meters accordingly contain amongst other impurities ,hundreds of parts per million of osmium, which slowly oxidizes in air to form highly volatile OsO4.

As a general rule, reviewers who check facts rigorously stop short at the first counterfactual they encounter. Yours is on Page 1 Para3.

• I have to agree with Russell on this, plus the long rambling intro about M&M etc. is a tedious way to make a point which can be easily stated clearly.

I don’t see why you choose different averaging periods for your two variable. Use Jan-Dec for both. If you want to find the lag with the highest correlation, do a cross-correlation analysis.

Also, dividing a temperature by “Kelvin” to pretend it is a dimensionless quantity you can subtract from ln(CO2) is not credible physics. What is “temperature per kelvin” supposed to be physically? Sorry, this is silly. This question of causality is crucially important and needs to be done competently. Please try again.

• IIRC, Rae Allen showed about 15y ago that SST correlated with d/dt (CO2) , far better than a simple lead/lag correlation.

Both with oceanic out-gassing and terrestrial consumption of CO2 by plants or production by decomposition, it is dCO2 that relates to temperature.

• “Also, dividing a temperature by “Kelvin” to pretend it is a dimensionless quantity you can subtract from ln(CO2) is not credible physics. ”

Some reading of the SI (International System of Units) Brochure (available online is open access) would be useful to learn how to express mathematically a physical equation.

Copying from section 5.4, “Rules and style conventions for expressing values of quantities”

“Symbols for units are treated as mathematical entities. In expressing the value of a quantity as the product of a numerical value and a unit, both the numerical value and the unit may be treated by the ordinary rules of algebra. This procedure is described as the use of quantity calculus, or the algebra of quantities. For example, the equation p = 48 kPa may equally be written as p/kPa = 48. ”

Read more in the SI Brochure.

• “I don’t see why you choose different averaging periods for your two variable. Use Jan-Dec for both. If you want to find the lag with the highest correlation, do a cross-correlation analysis.”

Yes Sir!

Note that we are able to reverse causality and do what you requested with a lag of minus three years. Please see our paper “Atmospheric temperature and CO₂: Hen-or-egg causality?”, Sci, 2 (4), 83, doi:10.3390/sci2040083, 2020.

I hope our Figures 11 and 14 in that paper satisfy your requests.

• Eli Rabett

To be picky ln{[CO2]/ppm} has no units, you need an estimate of the climate sensitivity in °C/(W/m2) as a multiplier so ΔT= A ln {[CO2]/[CO2]o} where [CO2]o is the concentration at some reference period. This is the dimensionally proper equation.

That implies that [CO2] has an effect on temperature as well as temperature on [CO2]. We know from measurements that more CO2 is being emitted by burning fossil fuels than remains in the atmosphere. We also have measurements showing that ~105 _+ 8 Pg C from these emissions has been absorbed in the oceans* and the biosphere has i** and we have measurements and theory on how temperature and salinity affect CO2 partial pressure in the gas phase above sea water*** where a difference of 1C corresponds at best to a few ppm.

Of course we know that the atmospheric concentration of CO2 has increased from ~290 to ~430 ppm over the last 150 years.

This poses some obvious problems for any statistical treatment which claims that CO2 concentration follows changes in temperature

*Feely, R. A., Sabine, C. L., Takahashi, T., & Wanninkhof, R. (2001). Uptake and storage of carbon dioxide in the ocean: The global co~ 2 survey. OCEANOGRAPHY-WASHINGTON DC-OCEANOGRAPHY SOCIETY-, 14(4), 18-32.

**Amthor, Jeffrey S. “Terrestrial higher‐plant response to increasing atmospheric [CO2] in relation to the global carbon cycle.” Global Change Biology 1.4 (1995): 243-274 and especially the annual cycle

***Weiss, R. F., Jahnke, R. A., & Keeling, C. D. (1982). Seasonal effects of temperature and salinity on the partial pressure of CO2 in seawater. Nature, 300(5892), 511-513.

• I do not think that the expression “ln{[CO2]/ppm}” appears anywhere in our paper. Notice, we use Δln[CO2] which is dimensionless per se (= ln[CO2]_t – ln[CO2]_t’ = ln([CO2]_t / [CO2]_t’). So, you can say: “This [i.e., what we write] is the dimensionally proper equation”.

Dimensional analysis tells us what a mathematical expression can be, not which is related to which. Therefore, statements like “implies that [CO2] has an effect on temperature as well as temperature on [CO2]” are not defendable, in my opinion.

• If I wrote ΔT= A ln {[Pigs]/[Pigs]o}, would that prove global temperature has an effect on pigs and vice versa?

• Eli Rabett

Hi Jim2

If the result of a calculation based on climate physics and chemistry gave you the result that the ln[Pigs] was proportional to the change in temperature, why yeah test that. It might be the case in a sty, but there is serious doubt it would apply to the globe.

• Hey Eli. Run a statistical correlation between pigs and T. You just might find a positive one.

• Eli Rabett

Jim2

As the pastafarians put it:

We believe that global warming, earthquakes, hurricanes, and other natural disasters are a direct effect of the shrinking numbers of pirates since the 1800s.

As the number of pirates decreased, global temperatures increased.

https://pastafarians.org.au/pastafarianism/pirates-and-global-warming/

However the disconnect with physics puts paid to the statistical correlation. It’s been fun and thanks for the reminder.

• Eli Rabett

demetriskoutsoyiannis

Again being pedantic, but there is a reason Δln[CO2] is dimensionless because it equals ln[CO2(t2)]/CO2(t1)] as I pointed out. ln[CO2] by itself is improper dimensionally because you can only take a log of a dimensionless number.

But that leaves you with the same problem.

1. You need a constant which relates ln[CO2(t2)]/CO2(t1)] to ΔT for your model. This relationship is derived from the physics of climate models showing that Δln[CO2] drives the increase in temperature and the models provide estimates of the constant. It is not a result of statistics

2. We know that [CO2] has grown by 140 ppm in 130 years.

3. We know that ΔT(global) has increased about 1K.

4. We know that the amount of fossil fuel burned in that time would have roughly doubled the observed increase of CO2 in the atmosphere if there were not sinks

5. We can trace that the excess CO2 from combusion has gone mostly into the oceans and some into soils/plants

6. We know that the increase in CO2 above sea water for an increase in temperature of 1K is only a few ppm

Therefore the observed increase in [CO2] cannot be driven by the observed increase in temperature

(see references in my earlier comment)

• Eli Rabett, no need to repeat (once more) the conventional wisdom (or official propaganda) taught to all of us every day by all types of media and even to kids at kindergarten.

• Eli,
“Therefore the observed increase in [CO2] cannot be driven by the observed increase in temperature.”

[CO2] is a trace gas (~400 ppm) in the Earth’s atmosphere. Earth’s atmosphere, as a whole, is a very thin substance to have any significant greenhouse warming effect on the Earth’s surface.
Earth’s atmospheric [CO2] content is too small to have any influence on the planetary radiative energy balance.

Eli,
“2. We know that [CO2] has grown by 140 ppm in 130 years.

3. We know that ΔT(global) has increased about 1K.”

Since the [CO2] 140 ppm do not influence the ΔT(global) temperature increase, thus there is only one conclusion:

The increase in [CO2] content by 140 ppm in 130 years is driven by the ΔT(global) increase about 1K.

https://www.cristos-vournas.com

• “Therefore the observed increase in [CO2] cannot be driven by the observed increase in temperature”

1. You need to account for the increase in respiration due to increase in temperatures. From experiment 1C change in temp causes (at least) a 26% change in respiration.

2. You need to explain the high variance in atmospheric CO2 that lag temperature change in the paleoclimatological record:

“The majority of the stomatal frequency-basedCO2 estimates for the Holocene do not support the widely accepted concept of comparably stable CO2concentrations throughout the past 11,500 years (Indermu.hle et al., 1999). The available high-resolution CO2 reconstructions based on plant fossils suggest that century-scale CO2 fluctuations contributed to Holocene climate evolution (Rundgren and Beerling, 1999; Wagner et al.)”

Kouwenberg 2004: “However, atmospheric CO2 levels are influenced by temperature- induced changes in biospheric and marine feedback systems. ”

Steinthorsdottir et al 2013:”ﬁrst to minimum values of 175-190 ppm at theGS-1/Holocene boundary (3.24 depth), before rising sharply to280-300 ppm, and staying at that level through the next 95years….This again indicates a ca 100 ppm rise in CO2 in <100 years"

"which marks a shift from a warmer to a colder climate state, CO2 increases markedly before the boundary and peaks at ca 400-425 ppm before it decreases again and then stabilizes after the boundary into a pattern of lower-amplitude
ﬂuctuations withaverage values of 230-250 ppm during GS-1"

• @ Eli Rabett – good summary. Thanks.

• Eli Rabett

Christos Vournas

“[CO2] is a trace gas (~400 ppm) in the Earth’s atmosphere. Earth’s atmosphere, as a whole, is a very thin substance to have any significant greenhouse warming effect on the Earth’s surface.”

“Earth’s atmospheric [CO2] content is too small to have any influence on the planetary radiative energy balance.”

At atmospheric pressure per m3 there are ~1E22 CO2 molecules/m3. Work that backwards and the average distance between them is about 5E(-8)m or 5E-2 microns. The IR wavelengths that CO2 absorbs are ~ 15 microns. QM is very strange, often stranger than we can think.

Another way of looking at it is to measure the absorption of CO2 in the 15 micron band. It turns out that the average distance a photon in that region can trave is about 10 m on the peaks of the rotational lines and about 50m in the valleys.

https://rabett.blogspot.com/2020/10/no-overlaps.html

It also turns out that the overlaps with water vapor (including the difference in concentrations) are very small. (same link)

Since 15 microns (or 650 cm-1) is the peak of thermal emission for something at 280K, yes, 400 ppm [CO2] can effectively block a significant amount of the IR thermal emission from the surface reaching space

• Eli Rabett

agnostic2015

The variation due to respiration is the source of annual variation in CO2. It’s been accounted for by direct measurement

https://www.co2.earth/seasonal-co2-cycle (with video)

• Eli Rabett,
“Since 15 microns (or 650 cm-1) is the peak of thermal emission for something at 280K, yes, 400 ppm [CO2] can effectively block a significant amount of the IR thermal emission from the surface reaching space”

The 288K is the Earth’s meassured average surface temperature. Earth’s surface doesn’t emit at 288K.

The planet’s upgoing radiation cannot be compared with the 288K emission curve.

“The large bite into the blackbody emission at ground level …” cannot be explained by the absorption by the CO2 and H2O.

The large bites show what earth’s surface has never emitted, when mistakenly comparing with the 288K emission curve.
The trace gasses in the thin Earth’s atmosphere are not capable to absorb so much IR radiation.

They have never absorbed what was not emitted from the Earth’s surface.

https://www.cristos-vournas.com

• Russell Seitz

If you poach it, it ends up cooked either way

https://vvattsupwiththat.blogspot.com/2023/09/why-didnt-they-think-of-climate-week.html

2. Norman Page

Amazing – The cause comes before the effect – somebody should tell the IPCC and the consensus scientists. Here is a quote from my Blog at https://climatesense-norpag.blogspot.com/
6. CO2 -Temperature and Climate.

“The whole COP Net Zero meme is founded on the flawed assumptions and algorithms which produced the IPCC- UNFCCC model forecasts of coming dangerous temperature increases.
The “consensus” IPCC models make the fundamental error of ignoring the long- term decline in solar activity and temperature following the Millennial Solar Activity Turning Point and activity peak which was reached in 1990/91 as shown in Figure 1

The amount of CO2 in the atmosphere is .058% by weight. That is one 1,720th of the whole. It is inconceivable thermodynamically that such a tiny tail could wag so big a dog. (13)

Stallinga 2020 (14) concludes: ” The atmosphere is close to thermodynamic equilibrium and based on that we……… find that the alleged greenhouse effect cannot explain the empirical data—orders of magnitude are missing. ……Henry’s Law—outgassing of oceans—easily can explain all observed phenomena.” CO2 levels follow temperature changes. CO2 is the dependent variable and there is no calculable consistent relationship between the two. The uncertainties and wide range of out-comes of model calculations of climate radiative forcing (RF) arise from the improbable basic assumption that anthropogenic CO2 is the major controller of global temperatures.
Miskolczi 2014 (15) in “The greenhouse effect and the Infrared Radiative Structure of the Earth’s Atmosphere “says “The stability and natural fluctuations of the global average surface temperature of the heterogeneous system are ultimately determined by the phase changes of water.”
AleksanderZhitomirskiy 2022,(16) says:
“The molar heat capacities of the main greenhouse and non-greenhouse gases are of the same order of magnitude. Given the low concentration of greenhouse gases in the atmosphere, their contribution to temperature change is below the measurement error. It seems that the role of various gases in the absorption of heat by the atmosphere is determined not by the ability of the gas to absorb infrared radiation, but by its heat capacity and concentration. ”
Zaichun Zhul et al 2016 (17) in Greening of the Earth and its drivers report “a persistent and widespread increase of growing season integrated Leaf Area Index (greening) over 25% to 50% of the global vegetated area from 1982 – 2009. ………. C02 fertilization effects explain 70% of the observed greening trend.”
Policies which limit CO2 emissions or even worse sequester CO2 in quixotic CCS green-washing schemes would decrease agricultural food production and are antithetical to the goals of feeding the increasing population and bringing people out of poverty.

The tropical rain forests and tropical oceans are the main source of the atmosphere’s water vapor and the rainfall essential to life and agriculture on land. Potable and agricultural water supplies are now stretched to their limits in many areas because of the differing national demographics of global population increase. Temperature limits and Net Zero CO2 targets as set in the Paris Accords to ameliorate future temperatures are completely useless when formulating policies relative to adaptation to the actual real world problems. These require more local inputs for particular regional ecosystems delineated by coastlines, major river basins and mountain range limited intra-continental divides.

• ganon1950

“The amount of CO2 in the atmosphere is .058% by weight. That is one 1,720th of the whole. It is inconceivable thermodynamically that such a tiny tail could wag so big a dog. (13)”

To quote Iago “You keep using that word [inconceivable]; I do not think it means what you think it means.”

[1] The major atmospheric components N2, O2, Ar are >99% of gaseous components (H20 is a special case) do not absorb infrared radiation. If molecules that do absorb IR are considered, CO2 is a major component, 2nd only to water vapor, with absorption near the peak of Earth’s blackbody radiation, and lying in the 12 – 18 micron H20 transmission window.
[2] Consider adding to a gallon of water 1 ml of blue food coloring (0.026%): Is it “inconceivable” that this could absorb a significant fraction of red light trying to pass through it? QED

3. Anonymous

thank you dr. curry for continuing to post relevant climate change articles. appreciate your comments at the end too.

4. David L. Hagen (HagenDL)

The foundation of modern science is the Royal Society’s motto “nullius in verba” (Take Nobody’s Word for it). https://royalsociety.org/about-us/history/
Koutsoyiannis and team provide a powerful breakthrough in extending scientific causality to effectively “kick the tires”.
Koutoyinnnis et al.’s quantifying how Temperature leads CO2 is vital application of causality theory with the very important application of testing models against evidence.
Finding today’s “Climate Change” models wanting that assert majority anthropogenic global warming may be unpopular is some circles. However it critically impacts how trillions of dollars of our taxes are spent, and the prosperity of our children and grandchildren.
Using cheap geologically stored solar energy is vital to continue to raise up the extreme poor into productive livelihoods. To compliment that we need a long term strategy to transition to sustainable fusion power (rather than prospering the CCP).

• Russell

Why must Ovid always be be misquoted?

He wrote :
Nullius addictus judicare in verba magistri quo me cumque rapit tempestas, deferor hospes— quo me cumque rapit tempestas, deferor hospes.

Roughly rendered as “Not compelled to swear allegiance to a captain’s words, wherever the storm drags me, I come ashore as a guest.”

The bet brief paraphrase may be Harry Truman’s

“I’m from Missouri”

• im suppose to take the word of a Motto.

This notion of Take no ones word for it.

stupid.

look at you taking the Royal societies word for it.

5. Javier

This issue has been beaten to death over the years.

The short term dependence of ΔCO2 on ΔT is due to to the biological response from plants, algae and phytoplankton. But this flux has a negative effect on the long term increase in CO2 which has a human origin.

So, what Koutsoyannis et al. are detecting is unrelated to the question of how much warming the anthropogenic increase of CO2 is causing.

It is not only that a change in CO2 causes a change in temperature and a change in temperature causes a change in CO2. It is also that both change due to different causes, so the relationship between both does not result in a clear correlation but the lack of correlation is uninformative about causality.

This scatterplot is from Figure 2D of Westerhold et al. 2020. It shows an incredible lack of correlation between CO2 changes and temperature changes during most of the past 55 million years. At almost any time either CO2 is changing or temp. is changing, but no diagonal is apparent until the mid-Pliocene is reached. Even more astonishing is that the authors, based on this data defend the opposite.
https://i.imgur.com/TsVyCRh.png

• We write: “We examined time scales ranging from months to decades.”

Please read the paper, in particular section 6, “On the Timescale of Validity of Results” before you speak about “short term dependence of ΔCO2 on ΔT”

• “Slopes” are seen when we increase the time scale. And we have done that. But we let the data speak for themselves, rather than dictating them what to tell.

• Javier

“in particular section 6”

I read it and I didn’t change my mind. CO2 shows an annual cycle as T does, and in that cycle CO2 from biosphere photosynthesis and decay responds to T. And on the 3-year scale you are detecting CO2 responding to ENSO, as has been known since the 1970s.

Other than its annual cycle and its responses to ENSO and volcanic eruptions, CO2 presents a rising trend since the 1950s, due to human emissions.

T changes a lot more on every temporal scale because it responds to any change in radiative fluxes and ocean-atmosphere heat fluxes. All those changes are unrelated to the cuestion of CO2-T relationship. T presents a rising trend only since 1976, so it is clear that radiative and heat fluxes dominate the decadal scale. That T changes independently of CO2 does not mean it does not change in response to CO2 changes. But it means the response will be much more difficult to measure. That’s why nobody knows the sensitivity.

The technique you are using will not give you the answer you are looking for. With that technique you can only detect the CO2 response to T explained in the first paragraph, so that will not settle the question of how much warming an increase in CO2 would produce.

• It’s obvious that you did not change your mind. I am afraid, whatever I say you won’t…. And I can hardly imagine something stronger than the information provided in our figures 4 and 5, which are for time scales up to two decades. You assert that “CO2 presents a rising trend since the 1950s, due to human emissions”. Well, you are not the only one, of course. But we show with data that this is clearly not the case. It violates a necessary condition.

The annual cycle is irrelevant to our analyses.

We are not “detecting CO2 responding to ENSO”. Actually, we show that CO2 responds to temperature, which responds to ENSO. See Fig. 13 and Appendix A3.

Apparently we have different views. But we support our view with data analyses. Actually, we have formed this view after we analysed the data. I guess your view is supported by climate models. But we also show, with analyses similar with those we used for real world data, that climate models have incorporated a causality direction opposite to the real one.

It is not correct that “T presents a rising trend only since 1976”. Please see our Figure SI3 (in Supplementary Information).

• Demetris, the slope of temperature in its derivative is zero with a slight offset from zero.
The slope of the yearly CO2 emissions ánd the increase in the atmosphere increases with a factor 3-4 over the period 1960-2020.

Besides that, the carbon mass balance shows that human emissions are fully responsible for the increase in the atmosphere with a small (13 ppmv) increase due to higher seawater temperatures since the LIA.
Both oceans and vegetation are proven sinks for CO2, not sources.

Your analyses only shows the cause and effect of the +/- 1.5 ppmv variability around the trend, not the cause of the 130 ppmv increase itself…

• Ferdinand, the difficult thing is to model the derivative–the change. It is then easier to get “the 130 ppmv increase” right. Please see section 9, “Discussion and Further Results”, where we write “The explained variance for Delta-ln[CO2] was drastically increased from 34% to 55.5% and that for [CO2] is an impressive 99.9%.”. In graphical form, the 130 ppmv are well reproduced in the lower panel of Fig. 15.

• Demetris,

There is a lot of the points in chapter 9.3 which could be discussed…

The influence of temperature on the CO2 levels is exactly known: around 16 ppmv/K as seen in the 420.000 years Vostok ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/Vostok_trends.gif
The average 8 ppmv/K is for Antarctic temperatures. For global temperatures, that gives around 16 ppmv/K for very long term changes (including deep ocean and vegetation changes) over thousands of years.

Further, the equilibrium CO2 level between ocean surface and atmosphere is directly controlled by the ocean surface temperature by the formula of Takahashi, which is independent of the seawater composition:
∂ln pCO2/∂T=0.0423/K
See: https://www.sciencedirect.com/science/article/abs/pii/S0967064502000036
That means that for the current average ocean surface temperature, the equilibrium would give around 295 ppmv CO2 in the atmosphere. That is all.

According to the IPCC figures that you used, human emissions are only 4% of all emissions, but human sinks are near zero and both oceans and vegetation are more sink that source, no matter how much faster the natural carbon cycle got. Even if it doubled: that has zero effect on the CO2 levels in the atmosphere, only the difference between ins and outs…

• Demetris, there could be a lot of discussion about what you wrote in chapter 9.3…

While there is an increase of the natural carbon cycle both in the oceans as in vegetation, that doesn’t influence the in/decrease of CO2 in the atmosphere, as long as the ins equal the outs. In this case the IPCC figures (and the measurements) show that both oceans and vegetation are net sinks for CO2, thus impossible that these have any contribution to the increase…

The slopes in the derivatives are clear enough:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8c.jpg

• Ferdinand, I don’t view the world as static and I am happy that it is ever changing. Hence, I don’t think that there were periods where “ins equal the outs”. [CO2] has also been changing. As we cite in our Appendix A.5 “the atmospheric [CO2] was much higher (up to 27 times) than the current one for most of the time during the phanerozoic”.

Actually, if the world was static, we would not exist. We are a result of change / evolution. And yes, our civilization emits CO2 (nb., this is not identical with saying that it increases the Earth’s temperature). But without that level of civilization we wouldn’t discuss in this blog. We wouldn’t have computers and models.

To emit CO2 or any other gas is not a sin, neither is the fact that “human sinks are near zero”. Undoubtedly, our existence and our civilization have also created problems (to ourselves). And we have effectively been remedying them all the time by employing civilization, technology and economy.

• Demetris, I do agree that there was a lot of CO2 variability over the period that the earth exists, but let us focus on recent time frames:

– Over the past 2 million years, the long term (multi-millennia) ratio between CO2 and T was about 16 ppmv/K as seen in ice cores (past 800,000 years) and sediments (2 million years).
– Over the past 1,000 years there was a small CO2 dip in the high resolution (20 years) ice core of Law Dome which shows about 10 ppmv/K for the depth of the LIA around 1600.
– Over the past 60+ years the short time (2-3 years) ratio is about 3-4 ppmv/K.
– Within a year, the ratio is about 5 ppmv/K over the seasons, but in opposite direction: warmer = less CO2.

Over the past 60+ years the CO2/T ratio is near 120 ppmv/K. That can’t be caused by temperature, that is physically impossible.

In the same period, humans emitted some 200 ppmv CO2.
The latter cause fits all known observations and violates none.
See: http://www.ferdinand-engelbeen.be/klimaat/co2_origin.html

One can discuss the effect of that extra CO2 on temperature, but that humans are the cause of the recent increase of CO2 is very solid science.

• Ferdinand,
You said, “That can’t be caused by temperature, that is physically impossible.” I would agree that temperature can’t be responsible for all the increase in the atmosphere if one assumes that it all comes from the oceans — but it contributes. What it appears that you are overlooking is that the Tundra is melting, contributing CO2 and CH4, which oxidizes to CO2 and H2O in about a decade. Additionally, NASA has documented ‘greening’ of the Earth, which means that there is more annual bacterial-CO2 from vegetation detritus. Lastly, recent submarine surveys have nearly doubled the known number of seamounts, meaning that there is the potential for a greater volcanic CO2 flux than is generally accepted, based on observations of terrestrial volcanoes alone. I think it is premature to assume that we have all the answers.

• Demetris, I too have concerns about the method used. When you plot the spectrum of the CO2 signal as I did here, you’ll find not only a strong spectral peak at 1 year, but also at 6 months (2 Year^-1) which is the delay you’ve observed, assuming I’ve interpreted your graph correctly. Further, the difference method used, when considered in the frequency domain behaves similar to a differentiator which enhances noise with frequency. The CO2 spectrum doesn’t have a lot of energy at the higher frequencies.

https://localartist.org/media/MaunaLoaCO2.png

OK, now for a bit of good news. I took the Mauna Loa CO2 data and computed the Frequency Response Function using HadCRUT5 global temperature anomaly data. Delay can be estimated from the slope of the phase response. A negative slope indicates that the CO2 is delayed relative to the temperature. A positive slope would indicate the opposite. This method avoids some of the potential pitfalls of the method you used.

Here’s the result computed using different observation lengths to allow different amounts averaging at the expense of frequency resolution. I’ve plotted a reference line corresponding to a 6 month delay of CO2 relative to temperature.

https://localartist.org/media/CO2_Temp_FRF.png

What this result appears to show is that the temperature precedes CO2 by about 6 months for the energy below 1 Year^-1.

• The way I see it (trying not to be too technical): On the timescales that the authors address, temperature does wiggles in CO2, humans do slope. Plants do much larger wiggles, but they don’t do much slope. The authors see wiggles (waves on the beach in the analogy) but can’t see slope. So they don’t address the effect of CO2 on temperature, which is a slope thingy.

• “Slopes” are seen when we increase the time scale. And we have done that. But we let the data speak for themselves, rather than dictating them what to tell.

• Sorry, I must have put the above reply here….

• Demetris, agreed that CO2 varies on all time scales, but let us focus on the past few million years up to the past 60+ years, where we have better and better data…

– Over the past 800,000 years the ratio between atmospheric CO2 and T is about 8 ppmv/K for Antarctic temperatures or about 16 ppmv/K for global temperatures. Confirmed by 2 million year old sediments over a longer time span.
– Over the past 1000 years, there is a small dip in the CO2 level in the high resolution (~20 years) Law Dome ice core of about 8 ppmv for a temperature dip of about 0.8 K (depending of what reconstruction you prefer) at 1650, the depth of the LIA.
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg
– Over the past 60 years, we see a variability of around 3-4 ppmv/K on short term (2-3 years) changes.
– Within a year, the seasons give about 5 ppmv/K, but… in opposite direction for CO2: higher T, lower CO2!

The CO2/T trend over the past 60+ years is about 106 ppmv / 0.9 K or near 120 ppmv/K, which is physically impossible…
In this case, T is not responsible for the increase of CO2.
In how far the increase of CO2 is responsible for the increase in T is a matter of discussion, but T is certainly not the main driver for the recent increase of CO2.

Further, by using Δln[CO2] i.s.o. Δ[CO2] you are hiding the enormous difference in trend between the temperature increase and the CO2 increase in the derivatives:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/wft_T_dT_dCO2_trends.jpg

Besides the two trends in the derivatives I have added the direct temperature trend, as some others (like the late Dr. Salby) wrongly compare the T trend with the dCO2/t trend, which gives spurious results…

• Ferdinand, could you tell where exactly we “are hiding the enormous difference in trend between the temperature increase and the CO2 increase in the derivatives”?

And if we were hiding that enormous difference, how would it be possible that our curves “data” and “model” are indistinguishable in the lower panel of our Fig. 15?

• Demetris, the visual difference is striking, but not essential. See your first figure and my figure where the full derivatives are compared:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_der.jpg

What is essential, is that in equations (8) and (9) you assume that the relation between T and CO2 is causal, which is impossible:
Near all variability is caused by temperature variability with a few months lag, but the trend is absolutely not caused by temperature: it is physically impossible to have an increase of 120 ppmv/K from a small temperature increase over 170 years, while the short-term variability shows only 3-4 ppmv/K and very long term (multi-millennia) changes show not more 16 ppmv/K…

While another one-way source provides about twice the observed increase…

• Should I repeat my suggestion to see our Fig. 15 and its discussion? I prefer not. You have already concluded that “the trend is *absolutely* not caused by temperature”. But I cannot see you suggesting any error in our model and methodology.

If you feel safe with your *absolutely* safe conclusions, you may keep them.

• Dear Demetris,

The discussion about Fig. 15 is here and now:
There is an increase of 100 ppmv CO2 in the atmosphere over the past 60+ years.

There is an increase in temperature of 0.9 K over the same time span (as seen in Hadcrutgl4).

That means that the CO2/T ratio gets about 110 ppmv/K.

There is no known natural source on this earth that delivers such an amount of CO2 as net result in such a short time span… The more that both oceans and vegetation are proven net sinks for CO2. Not sources.

Together with the known relation between T and CO2 from Takahashi (~16 ppmv/K), that disproves your assumption as base for Fig. 15 that temperature is the driving force for the observed CO2 increase…

• Javier, the mechanism which links surface ocean temperatures to atmospheric concentration of CO₂ is very well known by physicists. It is the solubility of CO2 in water. Warm Coca-Cola degases its CO₂, oceans too.
https://www.woodfortrees.org/plot/esrl-co2/from:1979/offset:-336.14/scale:0.013/derivative/mean:12/mean:14/normalise/plot/uah6/from:1979/offset:0.25/scale:1.8/derivative/mean:12/mean:14/normalise

• Paul. Nice graph. The offset and scaling are redundant since you normalise afterwards. I suggest 12,9,6 month triple running mean rather than 12,14 mo. Otherwise the CO2 lag is clear.

But as Mike Jonas pointed out all this is analysing the wiggles not the longer term secular increase.

6. So here is the question: given two processes, how can we determine if one is a potential cause of the other?
we proceeded to develop a new method to study the question whether process X is a potential cause of process Y, or the other way round.
In other words, instead of investigating the processes X and Y and find spurious results (as has been the case in several earlier studies), we study the changes thereof in time, ΔX and ΔY.
Yep, everyone is looking at ΔX and ΔY and no one is looking for a possible ΔZ that is likely more important as cause than either ΔX or ΔY.
Ice core records clearly indicate that ice extent is primary cause of temperature change and not result of temperature change, clearly, from much historic evidence CO2 change has been a result of temperature change, now, in addition some other factor is also causing CO2 change, an unknown ΔW.
Most on the different sides only look at ΔX and ΔY and not looking for ΔV or ΔW or Δ?[s].
Question everything and start looking at all the known evidence, without using consensus for any unknowns!

• Thanks for the comment. I think we look at “ΔV or ΔW or Δ?”; please see section 9, “Discussion and Further Results” and Appendices.

• You look at “ΔV or ΔW or Δ?” to some extent, but you stay constrained by climate consensus, which has multiple factors locked into incorrect assumptions, that limits and prevents, understanding of “ΔV or ΔW or Δ?”

• David L. Hagen (HagenDL)

By finding that Temperature LEADS CO2, Koutsoyiannis explicitly INVERT the “climate consensus” NOT ‘stay constrained by it”.
How do you logically argue that they are “locked into incorrect assumptions”?

• David L. Hagen, the point is that the conclusions from the authors is only valid for the short term (2-3 years) response of CO2 to short temperature variability of about 3-4 ppmv/K, not for 70 ppmv increase in the full 60+ years period…

The latter can’t be caused by the few tenths that the ocean surface increase in the full period. while human emissions were average twice the measured increase over the full period…

• Engelbeen says : “the conclusions from the authors is only valid for the short term (2-3 years) response”. Why “only valid” ? If a 1 year signal is followed some months later by a 1 year response, why wouldn’t the same mechanism produce a 400 year response to a 400 year signal ?
May be you are right (not sure), but you have to give, at least, some valid argument.

• paulabrin,

Because the 2-3 year response and the 400 year response are caused by different mechanisms.

For the 2-3 year response, we know that the main response is by vegetation. Here the graph:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_dco2_d13C_mlo.jpg
The increase in the derivatives for CO2 follows changes in T with a few months delay, which is what Demetris ea. did prove (and nobody disputes), but the interesting point is that the 13C/12C ratio goes down when CO2 goes up. That points to vegetation as source (e.g. by drying out of the Amazon during an El Niño).
Short term higher temperatures make that vegetation is even a net emitter of CO2 into the atmosphere, while long time increased temperatures are beneficial for plant growth…

If the increase was from warmer oceans, CO2 and d13C changes would parallel each other.
Still the oceans are a net sink for CO2 during an El Niño, as at that moment the CO2 rich upwelling near Peru stops, but the CO2/water sinks near the poles still go on.

Longer time scales like the MWP-LIA dip (~10 ppmv) up to 800,000 years ice ages/interglacials show that mainly the (deep) oceans are involved as there is only a small change in d13C for a huge (up to 100 ppmv) change.

And that humans are the main cause of the CO2 increase can be seen in the fast drop of the 13C/12C ratio in both atmosphere (ice cores, firn, direct measurements) and ocean surface waters (coralline sponges):
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.jpg

Vegetation and fossil fuels both have a low 13C/12C ratio of app. -26 per mil. The difference between the two can be calculated from the oxygen balance: If there is vegetation growth, then there is oxygen produced when CO2 is absorbed or reverse for plant decay. See:
https://tildesites.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
Last page, Figure 7 for an overview.

7. “And why does the temperature rise potentially cause an increase in CO₂ concentration?”
I think that the answer to this is found in an examination of the seasonal variations of atmospheric CO2. What I call the ramp-up phase during the Winter, appears to be the result of bacterial decomposition of plant detritus, respiration from tree roots (particularly boreal trees), and decomposition of photosynthetic plankton. If the temperature gets below freezing, the bacteria shut down. Above the freezing point, increasing temperatures cause an increase in bacterial activity. As the trees leaf out in May, they draw down the CO2 in the Summer, but not enough to counteract the Winter increase.

• Please note, seasonality does not play any role. We use difference series for differencing step of one year, so we reduced the effect of seasonal variations. Furthermore, we examine CO2 in the South Pole and the lags are the same, if not greater. Please see section 5, “Investigating the Possible Effect of Seasonality”. (Nb., we also analyzed other CO2 locations with similar results–not reported in the paper).

• You wrote:
“And why does the temperature rise potentially cause an increase in CO₂ concentration?”

The oceans are carbonated water, open a warm and cold carbonated drink and take note of the differences. The vapor pressure of the vapor CO2 depends on the temperature of the carbonated water.

More CO2 is proven good, it makes green plants that we depend on for life to grow better.

Looking at history, we are well inside of a “Climate Optimum”, the “Climate Optimum” as far as mankind is concerned. The most recent ten thousand years is Climate Paradise compared to the past fifty million years. The previous Climate Optimum was when the Dinosaurs roamed and we were not around.

• Why are oxygen levels dropping in the air and oceans if the rising CO2 is supporting more photosynthesis? Maybe those huge ocean hypoxia dead zones are a clue that just because it’s green doesn’t mean it’s good for the biosphere.

• Curious George

Oxygen level in the air is dropping by 0.1% per century. Let’s worry about it in year 3023.

• Clyde, I have reread the discussion there and you were completely wrong.
Even for the current discussion: the seasonal CO2/T ratio is opposite to the short to very long CO2/T ratio, as the main reactant on temperature changes is vegetation that removes CO2 with increasing temperatures, while on all other time scales CO2 increases with increasing temperatures…

• Ferdinand,
Your unstated assumption is that the ramp-up seasonal phase is equal to the draw-down phase. They are not equal. The ramp-up phase, driven primarily by bacterial decomposition of vegetation detritus and dead photosynthetic plankton (secondarily by respiration of tree roots), lasts longer than the draw-down phase, so that photosynthetic organisms are NOT a net sink unless they are buried where bacteria/fungus don’t have access. A significant amount of CO2 was removed during the Carboniferous, and more recently frozen in the Tundra. Both are now releasing that temporarily sequestered CO2.

• Clyde, indeed there are differences between the two phases as the first is just photosynthesis, while the second is by molds and bacteria and can go on even at freezing under a layer of snow…
The only important point is that the net result at the end of the year is more sink than sources, that is what the oxygen balance shows…

8. LS

Is it possible to kindly share the code and data used to produce the “quiz” figure?

• The software is Excel and the data sources are listed in detail in section “Data Availability Statement”.

9. El Nino episodes cause drying of tropical forests, which then release plumes of CO2, but the warm eastern equatorial Pacific El Nino waters are CO2 deficient.

El Nino episodes are teleconnected to lagged major warm pulses of the AMO (via negative North Atlantic Oscillation conditions), peaking around August, particularly during the warm AMO phases. That is part of the lag between El Nino driven temperature peaks and rises in CO2 levels. Because the North Atlantic is a major CO2 sink. And as the AMO is normally warmer during each centennial solar minimum, we can think of the reduced CO2 uptake as a negative feedback.

https://digital.csic.es/bitstream/10261/67041/3/Atlantic_Ocean_CO2_uptake.pdf

10. Joshua

I’m old enough to remember when Judith said something to the effect of, no one serious doubs the basic physics of the (anthropogenically caused) GHE, the only real question is the magnitude of the warming from anthropogenic emissions.

Times have changed.

• This has nothing to do with the current post Joshie. CO2 can be both a forcing and a feedback. The question is quantifying these effects accurately. In recent years there are some reasons to think its more complex than the simplistic IPCC model says. climate scientists used to say that the tropospheric hot spot was the “fingerprint” of global warming. When data failed to show this was happening, they said stratospheric cooling was the fingerprint. Now that stratospheric cooling seems to have flattened out, they have stopped talking about fingerprints. They are just riding the secular religion of climate catastophism despite evidence that the world keeps getting better and people keep prospering. The only negative effect of warming that looks undisputed is sea level rise.

• 1. Just because something gets put on this blog does not mean Judith agrees with it. I have found that she likes to put things here that help discussion and further the science. This article does that.
2. This paper actually does not cast serious doubts on the basic physics of GHE. Only the magnitude of the warming. That magnitude could well be within the error of the measurements and still exist. If so this method does not determine that it does not exist, merely that it is too small to be detected in the correlation.
3. Have a problem with the method? That would be a good discussion.

11. The established consensus has been that CO2 ppm before the industrial age was a feedback to global surface temperature changing the equilibrium concentration of CO2 saturated ocean surfaces. Ice core charts show CO2 ppm lagging temp peaks and troughs through the late Pleistocene. Then when humans began bringing sequestered carbon (fossil fuels) out of the ground CO2 ppm became a combination of anthropogenic emissions and the prior feedbacks. Following on this, as the CO2 ppm rises above the equilibrium ocean solubility for a given sea temperature the oceans become a CO2 sink and a negative feedback to CO2 ppm.

Does the current paper refute any of this?

12. ” I think what this paper shows is that CO2 is an internal feedback in the climate system, not a forcing (I think that Granger causality would reveal this?). “

Before the 19th century, it was. That is because nothing was forcing CO2. There was just a finite amount (about 2000 Gtons) of C in circulation, and whether it was in the sea, air or biomass was determined by climate variability.

But then a unique event occurred. We dug up about 600 Gtons C and put it in the atmosphere. Arrhenius in 1896 noticed this was happening, and calculated the warming trhat it would produce. Most other scientists since have agreed. And sure enough, it warmed. That is a causality that hasn’t happened before. And it will continue.

• Copying from our paper, section 9:

The mainstream assumption of the causality direction [CO2] -> T makes a compelling narrative, as everything is blamed on a single cause, the human CO2 emissions. Indeed, this has been the popular narrative for decades. However, popularity does not necessarily mean correctness, and here we have provided strong arguments against this assumption.

• But what you go on to say, which somewhat agrees with what I have said, is:
“However, popularity does not necessarily mean correctness, and here we have provided strong arguments against this assumption. Since we have identified atmospheric temperature as the cause and atmospheric CO2 concentration as the effect, one may be tempted to ask the question: What is the cause of the modern increase in temperature? Apparently, this question is much more difficult to reply to, as we can no longer attribute everything to any single agent.
We do not claim to have the answer to this ques
tion
, whose study is far beyond the article’s scope. Neither do we believe that mainstream climatic theory, which is focused upon human CO2 emissions as the main cause and regards everything else as feedback of the single main cause, can explain what happened on Earth for 4.5 billion years of changing climate.”

• David L. Hagen (HagenDL)

Nick By “Modern” I think he means since the depths of the Little Ice Age. The Minoan, Roman and Roman Warm periods and Little Ice Age cold were Not driven by CO2 but rather CO2 lagged T. Modern T leads CO2. The cause(s) of the previous warm/cold periods including the warming since the Little Ice Age are still open to quantitative analysis.

• Joshua

It’s more than just an assumption. It’s a theory based on physics. But more than that it implies a prediction. One of the best ways to explore causality is by making an assumption about what will happen with a change in a variable. And that’s what’s been done. And the prediction seems to follow. That’s not dispositive in and of itself, but that kind of prediction along with even perhaps even more importantly a dose effect between the change in the variable and the predicted outcome, presents a strong case.

• “Not driven by CO2 but rather CO2 lagged T. Modern T leads CO2. The cause(s) of the previous warm/cold periods including the warming since the Little Ice Age are still open to quantitative analysis.”

David,
There is very little evidence that CO2 changed at all during those periods (MWP etc). Yes, the cause of those periods in Europe is open to analysis, but has no relevance to CO2.

• Hi Nick. You and David created a question that the author’s conclusions need to address: did the Little Ice Age show a drop in CO2 from the Mediaeval Warming Period? If not, and the evidence for a significant drop in GMST between 1000AD and 1650AD, and there is no detectible drop in CO2, does this challenge the author’s theory, or at least put the resolution of the effect at the millennial scale? BTW, I replied to your comment on the Scafetta post.

• We use the term “assumption” for “the causality direction [CO2] -> T”. We also use the term “mainstream climatic theory” (as quoted above) for what is based on that assumption. But even if we call the “assumption” a “theory”, it does make it correct. I guess the “caloric theory” was a theory, but it was proved incorrect, once statistical thermophysics entered the scene. And since then, we can hardly speak of physics without statistics/stochastics.

The questions we tried to deal with are those allowed to study by the modern CO2 concentration data (Mauna Loa etc.). We did not want to delve into the controversial issue of data sets before that period.

In this, we do not propose a new climatic theory, but we try to see what the data say.

In any case, I do not believe that a theory of climate, whose very definition relies on stochastics, can be built without stochastics.

• Joshua

demetriskoutsoyiannis –

> I guess the “caloric theory” was a theory, but it was proved incorrect, once statistical thermophysics entered the scene.

I assume (yes, assume is appropriate here) that by “caloric theory” you mean the energy balance model related to nutrition? If so, I’d like to see where is was “proved incorrect,” as I’ve looked a fair amount and from what I’ve seen there’s quite a bit of controversy about that. There seems to be many with domain area knowledge who say that the energy in vs energy out model still applies, although over time the understanding of related factors has certainly complicated what was once considered a rather basic formula. But certainly, you won’t find ANYONE who questions whether there’s a causal relationship in place (between energy in and obesity, or energy in and energy out). In that sense it would be rather ironic if you’re saying that the nutrition energy balance model has been “proved incorrect” as an analogy, since certainly NO ONE would question the basic underlying causality or direction of causality there.

Further, it seems odd to me that your basic framing is related to the science of assessing causality as being “proved incorrect.” Certainly you must know that using “proved” in that context of causality is highly problematic.

Regardless, my more significant point, as opposed to the use of “assumption” versus “theory”, was that a key focus of addressing causality is related to making predictions as to what would happen when a variable related to the mechanism of causality changes over time. And once again, that’s what we’ve see here – which is generally considered pretty important as support for a theory of causal mechanism. And also importantly, the theory of an anthoropogenic GHE brings in a dose-response relationship which looks to pan out, one of the key components of the Bradford Hill criteria for establishing causality.

• Joshua: No, I mean the caloric theory.

Copying from wikipedia, https://en.wikipedia.org/wiki/Caloric_theory :

“heat consists of a self-repellent fluid called caloric that flows from hotter bodies to colder bodies. Caloric was also thought of as a weightless gas that could pass in and out of pores in solids and liquids.”

Don’t you think it was proved incorrect?

• Joshua

demetriskoutsoyiannis –

OK, sorry for my confusion.

Although in a general sense I have a problem with “proved” being used in a discussion of causality, I would imagine it would likely be reasonable in that context. As it would, of course, be for any number of theories from the 17th century. I’m not sure how useful that would be as an analogy, however. Sure, someone was the first to offer “disproof” of that theory from hundreds of years ago, and you might be the analogous scientists here offering “disproof” for an anthropogenic GHE, but I’m not able to assess your argument on its technical merits. At my level of assessment, I would say there’s a major difference between a 17th century theory being “disproven” over hundreds of years of further scientific development and someone saying they’ve disproven a theory that has WITHSTOOD decades of scientific interrogation along with ever increasing scientific sophistication. That is the context of your assertions. As such, imo, your use of caloric theory as an analogy actually weakens your argument.

Of course, that’s not dispositive. You could be the “disprovers” of an AGHE, but you’ve got the probabilities working against you – only made more disfavorable for you by analogy with the caloric theory.

At any rate, the aspects I’m most interested in you addressing remain unaddressed.

• “Everything” isn’t blamed on CO2, but the longterm warming trend since around 1980 has been. Year to year variations have many causes.

• Joshua, on the contrary, my example of caloric theory is absolutely relevant. It shows that it may take centuries before we can safely say that a theory is proved incorrect. (By the way, I don’t think that we used that expression for modern theories). And it may take even more centuries before the incorrectness is assimilated by the scientific community.

For example, the caloric theory, being deterministic, still remains the basis of thinking for many. Most colleagues contrast physics with statistics/stochastics. But there cannot be physics without stochastics–and this is particularly the case in climate.

There are cases where correct theories had been formulated but were not accepted for millennia (e.g. the heliocentric system and the explanation of the Nile’s floods; see details in my paper From mythology to science: the development of scientific hydrological concepts in the Greek antiquity and its relevance to modern hydrology, Hydrology and Earth System Sciences, 25, 2419–2444, 2021, http://dx.doi.org/10.5194/hess-25-2419-2021 ).

So, it is our duty, I think, when we think we find problems in existing theories, to try to highlight them. In this way, we may contribute to scientific progress. Otherwise, we can be sure that the wrong theories will prevail forever.

• Joshua

demetriskoutsoyiannis –

> It shows that it may take centuries before we can safely say that a theory is proved incorrect.

My guess it may have taken not hundreds but thousands of years to disprove you can control the rather by sacrificing virgins. How long did people believe the earth is flat?

I think that’s a rather weak platform to use for supporting an argument that decades of analysis by scientists using modern scientific technology, are equally likely to be wrong as people who were convinced about the benefits of sacrificing virgins or the dangers of sailing off the edge of the earth.

This is a quicksand discussion. Yes, accepted theories have been wrong in the past. That is not a valid support, imo, for the contention that any particular argument that runs against the mainstream is correct today. They are independent phenomena.

I await your response on the issues I’ve emphasized.

• I think I have answered your scientific questions and those related to epistemology and philosophy. I am not discussing your other issues, e.g. about virgins and flat earth, which are not scientific. As per the Bradford Hill criteria, we did not refer to those as they are suitable for human epidemiologic studies, while we study geophysical processes. We explain in this post and in the articles the peculiarities of the latter and why they need a different approach based on stochastics.

If you have specific questions on the papers, please let me know, but I do not think I can discuss other irrelevant issues.

• Joshua

demetriskoutsoyiannis –

I’m having trouble following your logic. You introduce one analog of a theory being disproven, and then bring up more such analogies, and then say you’re not interested in questions related to the relevance of other theories being disproven.

As for Hill’s criteria – I wasn’t suggesting that you should have addressed them in your analysis. Of course not! But because they were developed and usually applied in the context of epidemiology doesn’t mean that they aren’t useful for assessing causality in other contexts, imo. And of course the question of predictions made re patterns in outcomes in association with longitudinal changes over time in potentially causal variables has nothing to do with Hill’s criteria. .

Since I can’t analyze the technical issues at hand, I try to engage those presenting technical analyses in good faith engagement on the related aspects of their presentation – for example your discussion of how to meaningfully interrogate causality. That helps me to have a way of parsing technical exchanges when I read them. I can get a sense of patterns I bow people realm. In such a way I hope to get information to evaluate the probabilities of their technical analyses being sound.

Thank you for at least exchanging enough to give me some information in that regard, even if you have declined to do so further.

• At last, a kind reply, Joshua, thank you!

As I wrote, I can still reply to specific questions/comments on the papers, including on technical/methodological issues, but I reacted negatively in changing the stage from science to flat earthers and virgins.

• Joshua

demetriskoutsoyiannis –

> but I reacted negatively in changing the stage from science to flat earthers and virgins.

I can kinda understand that, but I think that your negative reaction rests on a basically arbitrary distinction, based on a subjective definition of what is or isn’t “science.”

My point was that virgin-sacrificers were operating on a view of causality, probably for a very long stretches of time. Again, the fact that they had a view on causality for a very long time, that has subsequently been “disproven,” isn’t directly relevant, imo, to whether you think you’ve “disproven” a causal relationship in anthropogenic, atmospheric CO2—> warming.

Regardless, saying that people have sometimes been wrong in the past is, imo, a weak platform upon which to stand up what seems to me to be your argument; that I should look at past long-enduring (scientific) errors as informative in evaluating the probabilities of your assertions being correct.

But if we follow what seems to be your distinction between science and non-science (for the sake of argument), we could just as well go with the long-standing “science” that the Sun orbits the Earth (as you brought up earlier).

What people with less sophisticated scientific methodologies believed for a long time is essentially irrelevant to whether or not a causal belief that ACO2—> atmospheric warming has or hasn’t withstood decades long interrogation with far, far more sophisticated scientific methods.

Indeed, it’s possible that you are another Galileo, but the fact that decades’ long interrogation with very sophisticated methodologies hasn’t “disproven” the anthropogenically caused GHE theory is far, far more relevant, imo, than that for thousands years people who had a very rudimentary understanding of the scientific method believed that the Sun orbited the Earth.

You seem to be suggesting the reverse and that doesn’t seem very logical to me. I think that decades of the AGHE standing up to modern scientific scrutiny is far more relevant than centuries of a belief among people with very little scientific sophistication believing in a geoctentric solar system (indeed, universe).

• “There was just a finite amount (about 2000 Gtons) of C in circulation, and whether it was in the sea, air or biomass was determined by climate variability.”

The White Cliffs of Dover, the huge volume of biogenic limestones worldwide, and the limey muds of the Bahamas argue against that claim.

13. These results agree with the work of Salby, Harde and Berry as well as others that do not think anthropogenic CO2 is the main cause of recent rise in atmospheric CO2.

• David, all three are wrong: if one adds 10 PgC/year as CO2 and the result is an increase of 5 PgC/year in the atmosphere, the difference is going into oceans and vegetation. Both are proven net sinks for CO2, not sources.
That means that there is no other possible cause of the increase. None.

The problem of the analyses by the late Salby, Harde and Berry is that they use the residence time (app. 4 years) as the rate of change of CO2 in the atmosphere, but that is the EXchange rate of change, not the speed of removal of any excess CO2 above equilibrium, which is around 50 years e-fold decay rate or 35 years half life time.

• Agnostic

No – you are far too certain of this. The processes that fix CO2 are much less temperature dependent than processes that release CO2 (biota decaying). That is an imbalance in the system, and why we see CO2 increasing in warm years with a lag. This holds true over ALL timescales with a couple of notable exceptions.

14. Thanks to the authors for their forthright analysis of this issue. Proponents of the IPCC consensus view of the carbon cycle miss two important points, of which Koutsoyiannis took full measure and drew the logical conclusions.

From section 9:

“In terms of the carbon cycle (point 1 above), several physical, chemical, biochemical and human processes are involved in it. The human CO2 emissions due to the burning of fossil fuels have largely increased since the beginning of the industrial age.

However, the global temperature increase began succeeding the Little Ice Period, at a time when human CO2 emissions were very low. To cast light on the problem, we examine the issue of CO2 emissions vs. atmospheric temperature further in the Supplementary Information, where we provide evidence that they are not correlated with each other. The outgassing from the sea is also highlighted sometimes in the literature among the climate-related mechanisms.

On the other hand, the role of the biosphere and biochemical reactions is often downplayed, along with the existence of complex interactions and feedback. This role can be summarized in the following points, examined in detail and quantified in Appendix A.1.

Terrestrial and maritime respiration and decay are responsible for the vast majority of CO2 emissions [32], Figure 5.12.

Overall, natural processes of the biosphere contribute 96% to the global carbon cycle, the rest, 4%, being human emissions (which were even lower in the past [33]).”

1. The vast majority of CO2 emissions from nature did not stop when humans began burning hydrocarbons. They continue to increase with warming and decrease with cooling.

2. Atmospheric CO2 is a result of two very different fluxes. The human one is a simple addition, but the massive natural one must be integrated over time in order understand its effect.

• According to Antarctic Ice Core Records, CO2 went up from 260 to 280, starting about five thousand years ago without a corresponding rise in temperature, where CO2 had followed temperature before that. Temperatures have not proportionally followed recent CO2 increase.

Temperatures are still currently very low compared to the most recent ten thousand year’s records. This warm period is colder than all previous warm periods in ten thousand years, in fifty million years.

15. “All evidence resulting from the analyses of the longest available modern time series of atmospheric concentration of [CO₂] at Mauna Loa, Hawaii, along with that of globally averaged T, suggests a unidirectional, potentially causal link with T as the cause and [CO₂] as the effect. This direction of causality holds for the entire period covered by the observations (more than 60 years).”

Simple quantitative mass balance arguments make nonsense of this. There is a very clear cause of the rise in CO₂ in the air. We are mining and burning C. If you look at the actual mass of C in the air over the last millenium, it was steady up until past 1800, despite those supposed huge natural emissions (which are actually just moving the same C around). Then, as we burnt carbon, the mass of C in the atmosphere increased in almost exact proportion. Half stayed in the air, half went into the sea.

The other fact is that, while there has been warming, it is nowhere near enough to account for the CO₂ rise. At the end of the last glaciation, CO₂ stood at about 180 ppmv. Then T rose by about 6°C, and CO₂ rose to 280 ppm, about a 55% rise. Since 1850 CO₂ has risen another 50%, but there has been nothing like a 6°C rise in T.

• Agnostic

That actually isn’t correct at all. If you focus on ice core CO2 proxies, then I can understand that point of view, but they are very coarse – approx 800 years resolution. Stomata and foraminifera show much greater variability. Some examples, MWP showed CO2 levels at around 390 ppm. Another example, during the Bolling-Allerod CO2 levels rose to over 420 ppm while temperatures were cooling, but then dropped precipitously.

On all time scales we can measure, temperature almost always precedes CO2 changes, with the above as an interesting exception. The reasons for that are unlikely to have stopped simply because man has contributed to CO2. It’s likely we have contributed to increase in CO2 but it’s clearly not considered that CO2 would have increased anyway inline with warm excursions for which we have a number of precedence throughout the holocene.

• Agnostic: again, stomata data are local/regional proxies with a local bias, they reflect local changes which can be enormous over a day and over the years.
Ice core inclusions are global and direct measurements of ancient air, thus NOT “proxies”, measured with the same equipment (GC or mass spectrometer) as for direct air measurements.
The only drawback is that the data are for a mix of 8 to 600 years. The resolution of e.g. the DSS ice core MWP is only 20 years, not 800 years and that shows some 10 ppmv/K dip for the MWP-LIA cooling. Not 110 ppmv/K. Not 390 ppmv during the MWP from unreliable stomata data… And it is the extra CO2 pressure in the atmosphere of 120 ppmv above equilibrium that presses extra CO2 into oceans and vegetation. If we stop our emissions, there is not the slightest chance that any natural flow will suddenly increase, because the CO2 pressure above equilibrium is still the same…

16. The null hypothesis has never been rejected, e.g.,

There is no scientific justification for some of the extremist economic and social penalties that a minority of zealots are trying to impose on the people of the world. ~Koutsoyiannis

…given that virtually no research into possible natural explanations for global warming has been performed, it is time for scientific objectivity and integrity to be restored to the field of global warming research. (Ibid.)

… they are unable to predict weather beyond a week or two, yet in conjunction with the IPCC they presume to tell us what to expect over the next few decades. (Ibid.)

17. David L. Hagen (HagenDL)

A challenging 2023 temperature jump followed by a later CO2 increase: “32% of Sea Surface Temperature warming since 1995 occurred in a mere 3 weeks within 2023” & “the surge in Global Sea Surface Temps PRECEDED the associated CO2 rise, by a full month…” @EthicalSkeptic on Twitter. Now to determine the cause. https://twitter.com/EthicalSkeptic/status/1666101958287978496

18. Judith, you wrote: “I think that Granger causality would reveal this?”

Yes, you are right. We had applied the Granger method in an earlier publication (http://dx.doi.org/10.3390/sci2040083), before we developed our new stochastic method.

As we detail in that paper, if we don’t difference the time series, the direction seems to be [CO2] -> T. But as we demonstrate in the paper, this result, which was also found in earlier publications by other authors, is spurious. It is an artifact produced by the very high autocorrelation of the raw time series. In particular, that of [CO2] is almost 1 for all lags (see Fig. 9 in thar paper).

When we removed the cause producing the spurious results, we found (quoting from that paper):

“For both lags η = 1 and 2 and for the entire period (or almost), T -> [CO2] dominates, attaining p-values as low as in the order of 10^−33.”

19. T, not ∆T, is the cause of ∆CO2.
∆CO2 = f(T)
Approximately
∆CO2 = C*T

• Please see section 9 “Discussion and Further Results”, and in particular Fig. 15.

• When specifying sampling on the interactive chart one can see the CO2 tracks HadCRUT very well. I also notice that during the volcanic eruptions of El Chichon (1982) and Pinatubo (1991) that CO2 scales higher than Temp and then by 1998 Temp is scaling higher with the super El Nino and likely suppression of CO2 in cooler years just prior. https://woodfortrees.org/plot/hadcrut4gl/from:1955/normalise/mean:9/plot/esrl-co2/mean:12/derivative/normalise/mean:9

I also see that CO2 track temperature in the Holocene prior to the industrial age. https://co2coalition.org/2021/10/29/15282/

• Charles Michael Scott

Interestingly, that is not what my plot on that site show. There is a consistent and definite lead of temps over CO2 since 1961. https://www.woodfortrees.org/plot/esrl-co2/mean:12/scale:0.2/isolate:60/plot/hadcrut4gl/isolate:60/mean:12/from:1961

• Charles Michael Scott:

“There is a consistent and definite lead of temps over CO2 since 1961.”

Very interesting. Have you published that graph in any scientific publication?

• To Charles Michael Scott, the effect is even clearer if you take the derivative of both series, it removes the possibility of a spurious correlation :

• The challenge of looking at the data in the time domain, is that there are different processes at work.

The annual co2 cycle, which is easy to see in these woodfortrees plots, is delayed less than two months ( 0.14 year), while most everything else has a six month delay.

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994090

• edimbukvarevic, please compare variables of the same order, the late Dr. Salby made the same error by assuming that CO2 increase is caused by the integral of temperature. That is a non-existing variable and implies that 1 K temperature increase will cause a CO2 increase until eternity…

paulaubrin by detrending in this case, you don’t remove a spurious trend, you just removed the real cause of the trend…

• Isn’t the simplest explanation for the plot correlations that global temperature fluctuations proportionally modulate the uptake of CO2? This would be consistent with a net global sink as well as short term temperature control of CO2.

• David Appell

Ron Graf wrote:
Isn’t the simplest explanation for the plot correlations that global temperature fluctuations proportionally modulate the uptake of CO2? This would be consistent with a net global sink as well as short term temperature control of CO2

Ron, do you wait to turn your car on until the temperature increases?

• David Appell

Bob Cutler wrote:
The annual co2 cycle, which is easy to see in these woodfortrees plots, is delayed less than two months ( 0.14 years)

Utterly false.

Atmospheric CO2 reacts immediately to changes in seasonal vegetation.

If not, where do you think the CO2 goes to hide for two months? The Moon maybe?

• David: “Do you wait to turn your car on until the temperature increases?”

I think you are saying that it’s obvious engine heat is created by the combustion, not the combustion by the engine heat. But that would not be the case if we never saw the engine turn on or off and did not know about spark plugs or glow plugs. (My first actually car kept running for a bit after turning it off.)

“Atmospheric CO2 reacts immediately to changes in seasonal vegetation.”

Bacterial colonies might take weeks to fully take advantage of an improvement in their temperature as well as die more slowly than their decrease in reproduction rate do to chilling. Or maybe the delay is in atmospheric mixing to the point of the top of Moana Loa. We didn’t make the data up.

• David Appell

Ron Graf wrote:
David: “Do you wait to turn your car on until the temperature increases?”

I think you are saying that it’s obvious engine heat is created by the combustion, not the combustion by the engine heat.

No, I’m not saying that at all.

Do you wait for the temperature to go up for that to happen?
Or do you emit CO2 regardless of the temperature?

In the industrial era, CO2 leads temperature.

• David Appell

Ron Graf wrote:
Bacterial colonies might take weeks to fully take advantage of an improvement in their temperature as well as die more slowly than their decrease in reproduction rate do to chilling. Or maybe the delay is in atmospheric mixing to the point of the top of Moana Loa. We didn’t make the data up.

Do you think bacteria decide to take a time out and sit around before chemically reacting to changes in temperature and carbon dioxide???

Do you?

20. Thank you to the authors for these works and thanks to Judith for publishing it.

It is worthwhile to point out the logically similar chicken-and-egg problem of total CO2 concentration vs human CO2 emissions.

When the trend of Mauna Loa-measured CO2 concentration and the trend of estimated fossil fuel emissions are detrended similarly to these excellent works on CO2 vs temperature by Antonis Christofides, Demetris Koutsoyiannis, Christian Onof and Zbigniew W. Kundzewicz, then it is shown by the same causality logic that CO2 from fossil fuels is not the cause of the increasing global CO2 concentration (i.e. the Keeling Curve.) The slope of fossil fuel CO2 emissions is not driving the slope of global CO2 concentration, thus CO2 emissions from fossil fuels burned by humans cannot be the cause of global temperature trends nor any other trends which are alleged to be co-dependent with global CO2 concentration, including warming or cooling, greening, desertification, climate change, sustainability, climate justice, polar ice melting, etc.

Responsiveness of Atmospheric CO2 to Fossil Fuel Emissions: Updated. by statistician Jamal Munshi, PhD., Emeritus Professor, Business Administration. (One of several papers on this subject by this data scientist. Links below.)

“ABSTRACT: The IPCC carbon budget concludes that changes in atmospheric CO2 are driven by fossil fuel emissions on a year by year basis. A testable implication of the validity of this carbon budget is that changes in atmospheric CO2 should be correlated with fossil fuel emissions at an annual time scale net of long term trends. A test of this relationship with insitu CO2 data from Mauna Loa 1958-2016 and flask CO2 data from twenty three stations around the world 1967-2015 is presented. The test fails to show that annual changes in atmospheric CO2 levels can be attributed to annual emissions. The finding is consistent with prior studies that found no evidence to relate the rate of warming to emissions and they imply that the IPCC carbon budget is flawed possibly because of insufficient attention to uncertainty, excessive reliance on net flows, and the use of circular reasoning that subsumes a role for fossil fuel emissions in the observed increase in atmospheric CO2.”

Full paper available:

https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2997420

These results are consistent with prior works that found no evidence to relate the rate of warming to the rate of emissions. Many examples of spuriousness and circular logic. Many references.

A list of papers by Dr. Munshi can be found here: https://papers.ssrn.com/sol3/cf_dev/AbsByAuth.cfm?per_id=2220942

• Thank you for your kind words about our works and for the links to the paper(s) of Dr. Munshi, which I was not aware of.

• joethenonclimatescientist

Budbromely – If I understand your logic –

In summary are you stating (somewhat similar to ) that the rate of co2 increase post 1950 greatly exceeds the rate of warming. While the rate of warming from circa 1880 to the 1940’s greatly exceeded the rate of the increase in co2?

apologies if oversimplyfing (or putting my own spin on it).

One question that has always baffled me is how the planet shifted from a cooling trend to a warming trend circa the late 1800’s when co2 increased from 280ppm to 281ppm. That shift from a cooling trend to a warming trend being comparable or greater that the current rate of warming

• Bud,

Munshi did make an essential error: she looks at the DEtrended variability of CO2 and compared that to human emissions which have a huge trend and hardly any variability.
Of course her conclusion is that there is no correlation, because she removed the cause of the trends…

Further, she attributes items to the IPCC which they never said or intended: the IPCC never said that human emissions should correlate with the yearly increase in the atmosphere. “driven by” is not equal to “should correlate”…

As human emissions were always higher than the increase in the atmosphere, there is no way that another (natural) source is the cause of the increase.

21. William Van Brunt

The paper: “On hens, eggs, temperatures and CO2: Causal links in Earth’s atmosphere” provides the greatest insight on the topic of causes of climate change in terms of objectivity and unparalleled analysis, I have come across.

The data analysis with respect to CO2 and it being an effect, not the cause, of climate change are unequivocally correct.

There is no question that ENSO SST changes drive changes in the average global concentration of water vapor, TPW, which drives and fully accounts for the YoY changes in mean global temperature some 5 months later and the decadal average increases in the devastation wrought by catastrophic weather, the percentage change in which changes as the of multiple of 130 x the decadal percentage change in TPW.

The 11% increase in TPW since 1972 drove a 24% increase in latent heat which drove a 400% increase in the incidence of catastrophic weather events and a 1,400% increase in resulting devastation which over this period is responsible for:

1. The loss of two million lives
2. 4 billion displaced or injured,
3. In terms of both intensity and incidence – more extreme heat waves, flooding, long term drought and driven famine and massive wildfires,
4. Extensive ocean heat waves, and,
5. Average annual, near term global economic losses of 170 billion USD, now a cumulative loss of more than 4 trillion USD.

The good news is that all of these effects of climate change are driven by changes in the concentration of water vapor. The data shows, this is reversed as the concentration of water vapor declines which occurs when average global precipitation exceeds the average global evaporation. Therein lies the solution to climate change.

22. It’s pretty obvious that what is being proposed here is simply wrong. It’s very clear that the increase in atmospheric CO2 that has occurred over the last ~100 years is due to human emissions and that this is the dominant drive of global warming. One probably doesn’t really need to go much further. However, if you do want to better understand the problem with the analysis presented here, you could read this PubPeer comment.

https://pubpeer.com/publications/7828A34E1F905217D557E4F8E93CC1#2

• This is not an argument which directly addresses the findings of these studies. Are you saying that the findings of these two papers, i.e. that the rise in temperature precedes the increase in CO2, is wrong? In which case what is your criticism of the methodology. Please demonstrate how you think it is flawed.

• What an honour to meet someone who knows that “…and Then There’s Physics”… Someone who knows in advance, in July 2022, that a paper that will be published in September 2023, will be wrong…. Who sees that this is “pretty obvious” and hence there is no need to suggest any errors in the methodology.

The only problem I see here is related to the follow-up post, also of July 2022, https://andthentheresphysics.wordpress.com/2022/07/27/revisiting-causality-using-stochastics

But it seems that the vision of Royal Society, which had published our two papers a couple of months earlier than July 2022, and to which this post was apparently addressed, was not clear enough to see that “It’s pretty obvious that what is being proposed here is simply wrong”. And thus, they did not retract our papers….

Let’s see if the editors of /Sci/, which published our new paper, have a better vision, so as to retract our new paper…

• As I thought was obvious, I was referring to the papers published in Proceedings of the Royal Society A, which presents the method and makes the same argument about atmospheric CO2 concentrations. Given that you refer to the two PRSA papers in the post above, I assume the method is the same in the new paper, hence the same criticism applies. However, to be blunt, anyone who thinks that the increase in atmospheric CO2 is not pre-dominantly due to anthropogenic CO2 is probably not someone who will get these basic arguments. Feel free to prove me wrong, but I’m certainly not planning to hold my breath (although, not doing so is not going to increase atmospheric CO2 concentrations).

• “As I thought was obvious, I was referring to the papers published in Proceedings of the Royal Society A”

But then you forgot to write “it’s rather embarassing that one of the Royal Society’s journals could publish a paper with what is, these days, a very obviously wrong result” (copying from your blog…).

• Joshua

It’s always interesting to see when “skeptics” argue that peer review is valuable, and when they argue it’s worthless.

I suspect there might be a pattern of causality but for the life of me I just can’t figure out what it might be.

• Peer review is hit and miss. In science, replication by one or more other groups or people is the gold standard. Even that doesn’t guarantee truth.

23. Al Porianda

All of the CO2 data begs the question as to how, when and where is the concentration measured. Early morning would typicall show higher CO2 levels and lower O2 levels in the sampling media whether it is atmospheric, marine or aquatic in temperate latitudes. The seasonal influence is also important to deduce causality. Individuals that understand these influences may be introducing error into their equations due to poor experimental set up. Two questions I ask is what gas is not a “greenhouse gas” and why has few researchers sided the CO2 concentrations with O2 concentration along with temperature and the locations, time of day and seasonal information? All Green plants do release CO2 when they respire at night. I have seen estmates for one mature oak tree releasing as much as 40 kg/year of CO2.

• Most base CO2 measurements are done as far as possible from vegetation and other possible sources/sinks.
That is e.g. at Mauna Loa on barren (volcanic) ground where most of the time the trade winds blow for thousands km over the oceans. Or other islands or at the South Pole, an ice desert or coastal when the winds blow from the seaside…
See the different base stations at:

• “… where most of the time the trade winds blow for thousands km over the oceans.”
And then are orographically uplifted, sweeping across the heavily vegetated lower slopes of the mountain, before encountering the “barren volcanic ground.”

• Eli Rabett

Keeling studied such daily variation and it was those observations that lead to selection of Mauna Loa for the CO2 Observatory where they would be minimized as described in the link below

https://library.ucsd.edu/scilib/hist/Keeling_Influence_of_Mauna_Loa.pdf

24. Ferdinand Engelbeen

I think that the authors don’t take into account that there are two important sources in case: temperature and CO2 releases from humans.

The influence of temperature on the CO2 levels is exactly known: around 16 ppmv/K as seen in the 420.000 years Vostok ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/Vostok_trends.gif
The average 8 ppmv/K is for Antarctic temperatures. For global temperatures, that gives around 16 ppmv/K for very long term changes (including deep ocean and vegetation changes) over thousands of years.

Further, the equilibrium CO2 level between ocean surface and atmosphere is directly controlled by the ocean surface temperature by the formula of Takahashi, which is independent of the seawater composition:
∂ln pCO2/∂T=0.0423/K
See: https://www.sciencedirect.com/science/article/abs/pii/S0967064502000036

That means that the effect of the ocean surface warming of app. 0.8 K since the LIA is good for about 13 ppmv CO2 increase in the atmosphere. That is all.

The observed increase of CO2 since the industrial revolution is about 130 ppmv. The calculated increase caused by human emissions, if all emissions remained in the atmosphere, is about 200 ppmv. That means that human emissions are the main cause of the increase, or one violates the carbon mass balance.

The difference is what oceans and vegetation did absorb. Since 1958 with the more accurate measurements at Mauna Loa and South Pole (and several other stations) in every year, nature was more sink than source, with some borderline El Niño events:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8c.jpg

The graph shows the increase of CO2 emissions from fossil fuel burning and cement manufacturing (light blue),
The small drop due to the Covid pandemic (purple) and the increase measured in the atmosphere (red).
The CO2 sinks in vegetation and oceans (green) is the difference between human emissions and the increase in the atmosphere.
The temperature variability is enhanced with a factor 3.5 to show the same amplitude as for the CO2 variability.
Everything is expressed in ppmv/year (1 ppmv = 2.13 PgC = 2.13 GtC)

Then what is the problem with the author’s work?
The point is that the authors did look at the variability around the increase, not at the cause of the increase itself.
Temperature indeed gives a fast response for the CO2 rate of change, lagging the temperature rate of change with about 6 months.
But in the derivatives, there is no slope at all in temperature (only a slight offset from zero), while yearly human emissions ánd the increase in the atmosphere increases with a factor 4 between 1960 and 2020…

While the authors are right for the short time (months to years) and very long time (centuries to multi-millennia) cause and effect of T on CO2, they are wrong about the current CO2 increase, which largely is caused by human emissions.

See for further information:
http://www.ferdinand-engelbeen.be/klimaat/co2_origin.html

25. According to the best evidence we have, humans have emitted ~700 GtC into the atmosphere since the beginning of the industrial revolution, including fossil fuel emissions, cement and industrial processes and land use change. The authors of this paper apparently have no idea where this carbon went. But concurrent with our emissions, CO2 concentrations have risen. This paper has no idea where this CO2 comes from, since both land and oceans have been net carbon sinks during this time frame. So if this paper is correct, temperature magically creates CO2. Is this even remotely believable?

Let’s do some simple math. Of the 700 GtC originating from human activity, about 44% stays in the atmosphere, and the rest gets absorbed by the oceans and land. So of our emissions, there is about 308 GtC in the atmosphere. That’s the equivalent of 1130 GtCO2. That can be converted to ppm by dividing by 7.81, so 1130/7.81 = 145 ppm. Funny how that corresponds pretty well to the amount of increase in CO2 above preindustrial levels.

So this paper wants us to believe that all this carbon we put into the atmosphere just disappears and then temperature causes CO2 to magically appear in the atmosphere at exactly the same quantities to match our emissions. Seriously?

For sure, CO2 is less soluble in warmer water, so warming SSTs will cause a ocean-to-atmosphere CO2 flux. During the glacial cycles of the Quaternary, this may account for as much as 100 ppm for a 5 C increase in CO2. or 20 ppm/C. At 1.2 C warming, though we’ve seen a 140 ppm increase in CO2, while the oceans have been a net sink, absorbing about 25% of our emissions.

This paper makes no sense.

• SJS,
You said, “3. You can’t explain why the increase in atmospheric CO2 corresponds EXACTLY with the amount of our emissions.”

It doesn’t. You yourself said, ” Of the 700 GtC originating from human activity, about 44% stays in the atmosphere, …” To be more precise, the increase in the atmosphere is numerically equivalent to 44% of anthropogenic emissions. You do not provide any evidence that it is actually anthropogenic.

26. Great paper … great discussion. Thanks.

• I thank you, billfabrizio! What an interesting contrast with the previous comment, which concludes “This paper makes no sense”…

• So do you have a response to the criticism above that preceded the conclusion “this paper makes no sense”? I haven’t seen one yet.

• Dear scottjsimmons, if someone had already concluded that your work “makes no sense”, would you find any reason respond?

• … *to* respond.

• Yes, if I believed my paper did make sense and the other person’s conclusion was erroneous, I might explain why my paper does makes sense. The fact remains that:

1. Humans are responsible for ~700 GtC emissions, and you don’t know where it went.
2. CO2 has increased by 140 ppm, and you don’t know where it came from.
3. You can’t explain why the increase in atmospheric CO2 corresponds exactly with the amount of our emissions.

27. I think that the authors don’t take into account that there are two important sources in case: temperature and CO2 releases from humans.

The influence of temperature on the CO2 levels is exactly known: around 16 ppmv/K as seen in the 420.000 years Vostok ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/Vostok_trends.gif
The average 8 ppmv/K is for Antarctic temperatures. For global temperatures, that gives around 16 ppmv/K for very long term changes (including deep ocean and vegetation changes) over thousands of years.

Further, the equilibrium CO2 level between ocean surface and atmosphere is directly controlled by the ocean surface temperature by the formula of Takahashi, which is independent of the seawater composition:
∂ln pCO2/∂T=0.0423/K
See: https://www.sciencedirect.com/science/article/abs/pii/S0967064502000036

That means that the effect of the ocean surface warming of app. 0.8 K since the LIA is good for about 13 ppmv CO2 increase in the atmosphere. That is all.

The observed increase of CO2 since the industrial revolution is about 130 ppmv. The calculated increase caused by human emissions, if all emissions remained in the atmosphere, is about 200 ppmv. That means that human emissions are the main cause of the increase, or one violates the carbon mass balance.

The difference is what oceans and vegetation did absorb. Since 1958 with the more accurate measurements at Mauna Loa and South Pole (and several other stations) in every year, nature was more sink than source, with some borderline El Niño events:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8c.jpg

The graph shows the increase of CO2 emissions from fossil fuel burning and cement manufacturing (light blue),
The small drop due to the Covid pandemic (purple) and the increase measured in the atmosphere (red).
The CO2 sinks in vegetation and oceans (green) is the difference between human emissions and the increase in the atmosphere.
The temperature variability is enhanced with a factor 3.5 to show the same amplitude as for the CO2 variability.
Everything is expressed in ppmv/year (1 ppmv = 2.13 PgC = 2.13 GtC)

Then what is the problem with the author’s work?
The point is that the authors did look at the variability around the increase, not at the cause of the increase itself.
Temperature indeed gives a fast response for the CO2 rate of change, lagging the temperature rate of change with about 6 months.
But in the derivatives, there is no slope at all in temperature (only a slight offset from zero), while yearly human emissions ánd the increase in the atmosphere increased with a factor 3-4 between 1960 and 2020…

While the authors are right for the short time (months to years) and very long time (centuries to multi-millennia) cause and effect of T on CO2, they are wrong about the current CO2 increase, which is largely caused by human emissions.

See for further information:
http://www.ferdinand-engelbeen.be/klimaat/co2_origin.html

28. Part 1 of a long comment:

I think that the authors don’t take into account that there are two important sources in case: temperature and CO2 releases from humans.

The influence of temperature on the CO2 levels is exactly known: around 16 ppmv/K as seen in the 420.000 years Vostok ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/Vostok_trends.gif
The average 8 ppmv/K is for Antarctic temperatures. For global temperatures, that gives around 16 ppmv/K for very long term changes (including deep ocean and vegetation changes) over thousands of years.

Further, the equilibrium CO2 level between ocean surface and atmosphere is directly controlled by the ocean surface temperature by the formula of Takahashi, which is independent of the seawater composition:
∂ln pCO2/∂T=0.0423/K
See: https://www.sciencedirect.com/science/article/abs/pii/S0967064502000036

That means that the effect of the ocean surface warming of app. 0.8 K since the LIA is good for about 13 ppmv CO2 increase in the atmosphere. That is all.

The observed increase of CO2 since the industrial revolution is about 130 ppmv. The calculated increase caused by human emissions, if all emissions remained in the atmosphere, is about 200 ppmv. That means that human emissions are the main cause of the increase, or one violates the carbon mass balance.

Further with part 2…

29. Part one of a long reaction…

I think that the authors don’t take into account that there are two important sources in case: temperature and CO2 releases from humans.

The influence of temperature on the CO2 levels is exactly known: around 16 ppmv/K as seen in the 420.000 years Vostok ice core:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/Vostok_trends.gif
The average 8 ppmv/K is for Antarctic temperatures. For global temperatures, that gives around 16 ppmv/K for very long term changes (including deep ocean and vegetation changes) over thousands of years.

Further, the equilibrium CO2 level between ocean surface and atmosphere is directly controlled by the ocean surface temperature by the formula of Takahashi, which is independent of the seawater composition:
∂ln pCO2/∂T=0.0423/K
See: https://www.sciencedirect.com/science/article/abs/pii/S0967064502000036

That means that the effect of the ocean surface warming of app. 0.8 K since the LIA is good for about 13 ppmv CO2 increase in the atmosphere. That is all.

The observed increase of CO2 since the industrial revolution is about 130 ppmv. The calculated increase caused by human emissions, if all emissions remained in the atmosphere, is about 200 ppmv. That means that human emissions are the main cause of the increase, or one violates the carbon mass balance.

30. Paul Roundy

You are analyzing the association between year to year variability in CO2 and temperature about the trend line. Your finding applies to that context: A truncated distribution of temperature losing the longterm trend varies from year to year as driven by temperature. This signal is consistent with temperature variation altering the year to year and seasonal fluctuations of CO2 more than year to year emissions control the year to year variation of temperature. The approach masks the longterm trendline, which would have a different direction of causation.

• Exactly. To my knowledge no one would be surprised to learn fluxes on seasonal or annual time scales may respond to temperature. That’s not evidence that the long-term increase in CO2 is due temperature and not to CO2 emissions.

• Looks like the ice cores confirm CO2 lags temperature.

https://rclutz.files.wordpress.com/2023/03/co2-and-temps-antarctic-ice-cores-gl-smith.png

• Mr Clutz,

Show where ice cores show 140 ppm increase in CO2 with a 1.2 C increase in temperature. Since CO2 is less soluble in warmer water, there is an ocean-to-atmosphere CO2 flux with warming. But since we started putting carbon in the atmosphere through our fossil fuel emissions, that’s all changed. Henry’s Law is pretty clear on this. The oceans and land are both net sinks, taking up about half of our emissions.

• Your assumption Scott. Humans are adding 4% on top of 96% natural emissions. And you are ignoring the longer term storage of CO2 (human and natural) in

• Scott, humans are adding 4% on top of 96% natural emissions of CO2. BTW the errors in estimating maritime and terrestrial emissions is greater than our 4%. So it’s an assumption to think they are sinks and no longer stimulated by the warming starting from the LIA. You also should not ignore the longer term storage of CO2 (human and natural) into calcium carbonate.

• Contrarians love to be confused about flux. Human emissions annually contribute about 4% of total emissions. They contribute about 0% of total sinks. Since the natural carbon cycle is nearly balanced, all the increase in CO2 is from human activity.

• That is one way CO2 can indeed work. How can you generalize from that? Our CO2 emissions certainly weren’t caused by temperature, and didn’t lag it. Why is CO2 today rising at the same time as temperature and not at a lag from it?

• SJS,
You said, “They contribute about 0% of total sinks.”
It has been shown that concrete takes CO2 out of the atmosphere. Your exaggeration does not lend credence to the rest of your claims.

• SJS,
You said, “Since the natural carbon cycle is nearly balanced, …”
An assertion for which the facts are not in evidence.

• Cyde Spencer,

Looks like I had missed these points from you:

“It has been shown that concrete takes CO2 out of the atmosphere. Your exaggeration does not lend credence to the rest of your claims.”
Still about 0% of total sinks.

“You said, ‘Since the natural carbon cycle is nearly balanced, …’
An assertion for which the facts are not in evidence.”
The evidence is in the IPCC report and is summarized right in the paper. Natural sources and sinks are nearly balanced with sources slightly smaller than sinks. The graph showing this is Figure A1 right in this blogpost. Human emissions flip that carbon cycle to a net source.

• “The approach masks the longterm trendline, which would have a different direction of causation.”

Sorry, Paul, as we discuss in the paper, the available instrumental data cannot give us answers about what happens on time scales longer than a couple of decades. We stick on what these data can say, without masking anything. And they say that, up to the time scales of a couple of decades, there is a unidirectional, potentially causal link with T as the cause and [CO₂] as the effect, while the opposite direction can be excluded as violating a necessary condition of causality.

• But your argument demonstrates that you agree with mine: Just because the dataset doesn’t allow you to extend to longer timescales doesn’t mean you can just assert that it works. You ARE masking the longterm trend & then just excusing it because that’s all the data allow. You can’t make assertions about a ~50 year trendline. Everything else is truncating the distribution so that the relevant data is lost.

31. It’s not an assumption that you just failed to supply evidence that 1.2 C warming can produce a 140 ppm increase in CO2. It’s also not an assumption that you don’t understand the carbon cycle. Annually, nature adds about as much carbon as it contributes to the atmosphere. The increase is 100% caused by human activity. There is no rational objection to this.

32. thecliffclavenoffinance

The authors claim : “In fact, human emissions are only 4% of the total, natural emissions dominate,”

It is human emissions that increased atmospheric CO2 by 50% since 1850.

There are lab spectroscopy measurements of the effects of increasing CO2. The authors make no attempt to refute those studies by claiming CO2 acts completely differently in the atmosphere.

Ms Curry wrote:
“Again, as emphasized in the paper, human emissions are small fraction of natural emissions”

That statement is false. The seasonal carbon cycle flows should not be called CO2 emissions. They do not increase the year over year CO2 levels. The human CO2 emissions should be called emissions because they DO increase year over year atmospheric CO2 levels. And they have been increasing atmospheric CO2 since 1850.

In summary, the authors have no idea what they are talking about, and it is very sad that Ms. Curry finds this article to be worthwhile.

She has apparently lost touch with real climate science to join the fantasy world of science denial, where CO2 is imagined to NOT be a greenhouse gas increased by human CO2 emissions that impedes Earth’s ability to cool itself at night.

• “The authors make no attempt to refute those studies by claiming CO2 acts completely differently in the atmosphere.”

That is not an unreasonable assumption. The behavior of a single variable in a controlled experiment can be quite different from the unconstrained behavior in a complex dynamic system with feedback loops.

When empirical evidence contradicts a hypothesis, I go with the data.

33. David Andrrws

Climate contrarians run around in circles. A paper by Humlum and others did a similar analysis and made similar wrong conclusions a decade ago The notion that the bulk CO2 rise is caused by temperature is soundly rebutted by the simple fact cited by Engelbeen and others here: emissions are 2x the atmospheric rise, insuring that land/sea reservoirs have been net sinks throughout the industrial era. I cannot help but notice that the authors have made no response to this.

Dr. Curry recommended this paper to us even though she states clearly in her book that humans are responsible for the CO2 rise. Dr. Curry, I believe you owe us an explanation for your endorsement of a rehashed argument that you had apparently once rejected. Can YOU explain to use how sinks cause the rise? I think not.

• Joshua

> Dr. Curry recommended this paper to us even though she states clearly in her book that humans are responsible for the CO2 rise.

Judith has stated for years that she doesn’t listen to anyone who dismisses the basic GHE. She has mocked people who describe “skeptics” as rejecting the basic GHE, and stated that “skeptics” don’t question that theory, they only question the magnitude of the warming effect. This is even as she has in the past, stated that some theories that dispute the basic physics of the GHE are “interesting.” She took the same position on Salby’s work.

>Dr. Curry, I believe you owe us an explanation for your endorsement of a rehashed argument that you had apparently once rejected.

Take note – although promising to do so, Judith NEVER provided a scientific analysis of Salby’s theories. I suspect you won’t be getting any such explanation here.

• I love how Dr. Curry’s blog brings out the control freaks.

34. The greenhouse effect is different from the carbon budget. This paper is about the carbon budget, and Salby’s papers were about the carbon budget (not the greenhouse effect).

My book states that there are quantitative uncertainties in the carbon budget.

This blog is about discussing interesting (and sometimes controversial) topics.

Disagreement and debate is the spice of the climate blogosphere. We all stand to learn something.

• Dr. Curry,

With all due respect, the carbon budget doesn’t allow the conclusions of this paper. Human emissions of CO2 are about double the increase in CO2 concentrations, and both land and oceans are net carbon sinks. That means that if the measured increase in atmospheric CO2 doesn’t come from human emissions, then human emissions must magically disappear, and temperature must magically generate CO2 in about the same quantities of our emissions. This is absurd.

• Demetris,

While you have used the IPCC data, your conclusion is quite different…

So where is the problem?
The problem is in the assumption for equations (8) and (9) where you assume that not only the short term variability (+/- 3-4 ppmv/K) is caused by temperature variability, but also the trend over the past 170 years and that is physically impossible, as that includes a response of 120 ppmv/K…

That you can “predict” the past 60+ years increase is due to the fact that you have guessed the best fit parameters with an algorithm, not based on any physical process…

The maximum increase in the atmosphere over mid- and very long periods is about 16 ppmv/K, as observed over the past 2 million years…

• No, our calculations are based on the physical process that temperature rise leads to increasing [CO2], which we substantiate in our paper.

• “… and temperature must magically generate CO2 in about the same quantities of our emissions.”

Maybe you just aren’t looking in the right places. Natural sources swamp anthropogenic emissions. The uncertainties in the Carbon Cycle could easily result in confusing sources. Something that doesn’t get mentioned is the melting in the Tundra, which is a result of increasing temperature — about 2-3X the global average. Probably Winter respiration of boreal tree roots are increasing from the increasing Arctic temperatures. Also, the submarine emissions of CO2 may be a serious underestimate considering that a recent survey nearly doubled the known number of sea mounts.

• Demetris,

The short term (2-3 years) variability that you use to prove that temperature is the main driver for the CO2 increase is going in the opposite direction of the general CO2 trend: the variability in CO2 is the variability in net uptake (not net release!) by both vegetation and oceans. That trend is increasingly negative. Thus never can be the cause of the increase in the atmosphere.
See: http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8.jpg

Further: the exact influence of temperature changes over longer periods on CO2 levels is known by the formula of Takahashi for the ocean surface:
∂ln pCO2/∂T=0.0423/K
Or about 13 ppmv since the depth of the LIA. That is all the influence of temperature on CO2 levels over the past 1,000 years.

For vegetation, the net sink rate also grows with more CO2: the earth is greening… Thus only a negative influence on the CO2 increase.

If we plot human emissions, increase in the atmosphere and net sinks, then we have:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/delta_p.jpg

In the first graph, we have plotted the calculated human emissions, the observed CO2 level in the atmosphere, the calculated influence of temperature on CO2 levels and the difference in pCO2 calculated from the observed CO2 level and the temperature caused CO2 increase. That is the driving force for the uptake by oceans and vegetation.

The second graph is the observed net sink rate of CO2 into oceans and vegetation.

The third graph is the calculation of the e-fold decay rate (~50 years) as result of the increasing pCO2 difference between atmosphere and ocean surface.

What is important:
– The observed variability in net sink (not source) rate is peanuts compared to the total increase of CO2 in the atmosphere.
– The total influence of the temperature increase since the LIA is only some 10% of the increase, all the rest is from human emissions.
– The lead of temperature in the variability is around a negative trend in net sink rate, while the atmospheric CO2 level all the time is positive.

That all means that your conclusions are based on a wrong assumption: that the lead/lag as seen for the variability around the trend is applicable for the lead/lag of the trends…

• Well, I do think it is quite possible that some of the increase in CO2 is due to a warmer climate. But I agree that the majority must have been due to fossil fuel combustion.

The reason the carbon budget is very important is we don’t understand it very well and its a big source of uncertainty. It is possible that as CO2 increases ecosystem productivity will go up a lot increasing carbon sequestration in forests, sedimentation in the oceans and lakes and weathering of rocks. This was a point made by Freeman Dyson. That’s perhaps why activist scientists don’t want to discuss it because its a benefit of more CO2.

I still don’t understand the ritual garment ripping that accompanies controversial papers and theories. It’s obviously politically motivated and mostly by known activists who often can’t offer any real scientific critiques. And that’s the key here. With the exception of Nick Stokes, the detractors commenting here offer nothing that has scientific merit.

• The problem with this paper and similar papers from Berry, Harde, the late Salby is that these violate at least the carbon mass balance and several other observations.

The carbon mass balance is quite accurately known with small error margins, because we have good knowledge of human emissions and good measurements of the CO2 increase. That is all we need.
No need to know any natural flux or its variability, as we know the end result: more sink than source.

Human emissions are around twice the increase in the atmosphere and every year since 1958 larger than what remains in the atmosphere. Thus nature is a proven sink for CO2. Not a source.

Whatever the (temperature induced) variability of the CO2 increase, there is simply no room for a large part of the increase due to temperature.

Any theory or calculation that violates one (or more) observations is to be rejected.
Including this paper.

• Salby’s argument, if I understood it correctly, was that CO2 is constrained by temperature, and that the system alters the natural sources and sinks to balance the CO2 concentration regardless of what our emissions are. You can’t deflect this argument by simply asserting that the sources and sinks in balance led to an increase that was determined by our emissions because we know the size of our emissions. If he was right, a reduction of our emissions under conditions of rising concentrations would still leading to increases at the same rate. I’m not satisfied with the evidence he presented, but his point can’t be deflected just by arguing the we created the imbalance. The real problem is that he didn’t present evidence how the system achieves what he suggests. If sources and sinks don’t respond enough to temperature AND concentration, then concentration isn’t determined by this balance, and adding CO2 will cause an increase in concentration.

• Ferdinand, could tell us where exactly our paper does “violate at least the carbon mass balance” and which exactly are the “several other observations” that it also violates?

-We just use observations, as they are registered in official databases.

– We use the IPCC carbon mass balance; see Appendix A1.

• I think Ferdinand you are offering a too simplistic logic. Without any temperature increase, there would be less CO2 in the atmosphere because the outgassing would be less than it is. It’s a legitimate question what the size of this effect is.

• Demetris and dpy6629

Indeed the logic may seem simplistic, but my experience with very smart people like Salby, Berry, Harde and many others is that they have troubles to understand simple things like a household budget, which (hopefully) any housewife/man understands: If you spend more money than you earn, you run into trouble…

“Since we have identified atmospheric temperature as the cause and atmospheric CO2 concentration as the effect”
From the text is the main point in this discussion.

The authors have proven that all the variability of CO2 is caused by temperature variability.
I don’t think that many people on this earth will dispute that.

Then the authors use that to “prove” that the total increase in the atmosphere since 1958 also is caused by temperature and that is simply impossible.

The carbon mass balance is as follows:

Increase in the atmosphere = human emissions – human sinks + natural emissions – natural sinks

The increase in the atmosphere is quite accurately known: 2.5 ppmv/year with an error margin of +/- 0.2 ppmv
Human emissions are quite accurately known from fossil fuel use (taxes!) and burning efficiency, maybe somewhat underestimated, due to human nature to avoid taxes, but certainly not overestimated: 5 +/- 0.5 ppmv/year
The main natural fluxes are only roughly known due to ocean surveys and the oxygen balance for vegetation.

For the current budget app. per year:
2.5 ppmv = 5 ppmv – 0 ppmv + X – Y

X – Y = -2.5 ppmv

No matter what X and Y are, Y is always 2.5 ppmv larger than X with a small error margin.

If X = 10 ppmv then Y = 12.5 ppmv
If X = 100 ppmv, Y = 102.5 ppmv (app. current natural cycles)
If X = 1000 ppmv, Y = 1002.5 ppmv

Thus it doesn’t matter at all how much natural CO2 is cycling through the atmosphere from other reservoirs, human emissions are the main cause of the increase…

• Ferdinand, I appreciate your calculations. But I guess we are discussing ours in this blog post. So, if you find errors in ours, as reflected in our Appendix A1 and our Fig. A1, please let us know–and also let the IPCC know, because our figure is entirely based on the IPCC estimates.

• It seems that some comment of mine still is somewhere in cyberspace, but here in short:

The main error of this paper is in one assumption that precedes formula (8) and (9):

The authors assume that the cause and effect found in the short term CO2 rate of change variability also can be used for the longer time (decades) trend.

That assumption is wrong, because the year by year variability has little to do with the 60+ years trend, which is (near) fully caused by human emissions.

The short time ratio is about 2-3 ppmv/K for 2-3 years temperature variability. For many thousands of years, the ratio is about 16 ppmv/K.

By iteration a “best guess” factor can be found to fit the Mauna Loa data, but that has no physical ground: that implies some 120 ppmv/K effect of temperature on CO2 levels which is physically impossible.

• “The main error of this paper is in one assumption that precedes formula (8) and (9): The authors assume that the cause and effect found in the short term CO2 rate of change variability also can be used for the longer time (decades) trend.
That assumption is wrong, because the year by year variability has little to do with the 60+ years trend, ”

Main error? Short term? Our results did not indicate time precedence of CO2 change over temperature change for any time scale that the data allow to study, i.e. up to a couple of decades. Can you make calculations similar to ours, i.e. based on bare data and not on conjectures and models, that support the opposite direction?

• Paul Roundy,

The problem of the late Salby’s approach is that he compared the increase of temperature with the increase of the derivative of CO2.
Then he used the integral of temperature to calculate CO2 as if that temperature was the main driver for the CO2 increase.

That is plainly wrong: compare temperature with CO2 or the derivative of temperature with the derivative of CO2, not the temperature with the derivative of CO2…

Moreover what is the integral of temperature? A non existing physical unit.
The effect of e.g. 1 K increase in temperature sustained over a long period would give a constant increase of extra CO2 in the atmosphere until eternity or opposite for 1 K cooling…

Why Salby (and others) were wrong is understandable: if you plot dT/dt with T and dCO2/dt then you will see that both dT/dt and T have almost exact the same variability, but with a 90 degrees shift in time… dT/dt has no slope, T and dCO2/dt have a slope:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/wft_T_dT_dCO2_trends.jpg

That makes that the variability in dT/dt is the proven driver for dCO2/dt, but T variability near completely synchronizes with dCO2/dt variability and nobody can say which one drives the other.

Any sinusoidal variable behaves in similar way…

• Joshua

Judith –

So just to clarify, you’re saying that this analysis doesn’t put into question the basic physics of the GHE, which you fully accept, but despite that we’re pumping so much ACO2 into the atmosphere there may not be any warming effect from those CO2 emissions?

Do I have that right?

I get that there are carbon sinks but I’m guessing you agree they don’t completely account for the CO2 emissions. In which case wouldn’t the GHE imply that the remaining CO2 would necessarily warm by virtue of the GHE?

Hopefully you’ll explain that logic in simple terms I could understand.

I guess it might be related to your argument that despite saying you don’t question the basic physics of the GHE, and despite continued ACO2 emissions, you believed there was a “pause in global warming” based on a temporary decrease in the rate of increase in surface temperatures only (basically ignoring OHC despite the significant role OHC plays the energy budget).

Of course, a similar kind of logic led you to predict 10 years ago, a continued “pause” of global warming into the 2030s. What’s your assessment of that prediction some 10 years in? Do you think it has been validated? If not, why not? Just not enough time yet it or was there some kind of conceptual problem with your theory of the mechanism of warming/cooling/not warming?

Tia.
.

• I’m not answering for Dr. Curry, but just a note: No matter if the source of the increase in CO2 we see is anthropogenic or from other sources, it is increasing. Dr. Curry has stated she believes about half the warming is due to the increase. AFAIK, she has never stated CO2 does NOT increase surface warming.

• Joshua

Jim –

> . AFAIK, she has never stated CO2 does NOT increase surface warming.

So I’ve never understood that. How could there be a “pause” in global warming” (as Judith testified to before Congress) if the emissions which (at least in part) cause warming didn’t pause?

At best, seems to me, what we saw was a temporary decease in the rate of ongoing increase in warming. IOW, at best a “pause” in one (relatively less indicative) signal of global warming and NOT a “pause in global warming.”

• Well, Josh, pauses in surface temperature increases are a fact. Obviously, there are factors other than CO2 levels that affect it. I believe that is part of what some scientists are attempting to dissect.

• Joshua

Jim –

> .Well, Josh, pauses in surface temperature increases are a fact.

Weko, as near as I can tell, that seems to me to be a matter of perspective and not a “fact.” . What some would call a “pause,”* others would call noise in a long term trend of consistent increase. Especially if there’s no theory of casual mechanism to explain the supposed “pause.”

Judith offered such a theory of causal mechanism. Is it time yet to reevaluate that theory?

* looking beyond the strangeness of calling a (possibly temporary) decrease in the rate of increase in one, relatively less indicative metric, a “pause in global warming (as if OHC doesn’t exist/isn’t a more indicative metric).

35. David Andrews

Dr. Curry,
Yes, Salby’s papers were about the carbon budget and they were wrong. The carbon budget is quite well constrained. Read Ballantyne et al’s 2012 Nature paper. There is no room for the conclusions of this paper.

I know you preach uncertainty. Invoking it here is tantamount to promoting misinformation.

• David,

And it’s one thing to invoke the need to acknowledge uncertainties. It’s quite another a to assume all uncertainties work in your favor. And in this case, even if you did make that assumption, the conclusions of this paper are still impossible.

• “the conclusions of this paper are still impossible”

I am taking a note of this; I may use it as a motto for a next paper….

• “Invoking it [this paper] here is tantamount to promoting misinformation.”

Thanks for unveiling that the origin of some of the reactions against our papers and Dr. Curry’s stance are of political type, related to the “misinformation agenda”–a euphemism to silence or at least censor opinions that do not serve the interests of those making the agenda.

Please see the quotation we use as the motto of our paper by none other than Carl Sagan. I repeat part of it here:

“The suppression of uncomfortable ideas may be common in religion and politics, but it is not the path to knowledge”.

• demetriskoutsoyiannis,

The issue here is that you have yet to respond to the substantial criticisms of your paper. Let me state these to you as questions:

1. Given that humans have emitted ~700 GtC into the atmosphere, if that has not raised CO2 concentrations, where did all that mass of carbon go?

2. Given that land and ocean are both carbon sinks, if the increase in atmospheric CO2 didn’t come from human emissions, where did it come from?

If you can’t answer these questions, you can’t make a case that temperature is causing CO2 to increase, and not the other way around.

It is completely unsurprising that some carbon fluxes respond to temperature. This can be observed seasonally and even annually with ENSO. But long-term you have to account for the carbon cycle and human emissions of carbon.

• Actually, the “substantial criticisms” are not criticisms. They are questions already replied to by our Fig. A1. But I will explain the replies in words (even though I am not sure if words can be better understood than geometric depictions). I will use annual rates (Gt/year) for the current period rather than cumulative quantities for all years, in accord to what is depicted in our Fig. A1 and IPCC’s Fig. 5.12.

“1. Given that humans have emitted ~700 GtC into the atmosphere, if that has not raised CO2 concentrations, where did all that mass of carbon go?”

Every year, of the 9.4 Gt/year of CO2 fossil fuel emissions (or 9.4/3.7 = 2.5 Gt C), plus other additions tantamount to 50.2 Gt/year (see decomposition in question 2 below), a quantity of 5.1 Gt CO2 (named “Balance” in our figure) is stored in the atmosphere. The remaining quantity is intercepted by absorption and photosynthesis in the terrestrial and maritime parts of the Earth, at a proportion of 142 / 79.5 = 1.8:1 (see the numbers in the figure).

“2. Given that land and ocean are both carbon sinks, if the increase in atmospheric CO2 didn’t come from human emissions, where did it come from?”

The increase in atmospheric CO2 comes from:

(a) an increase in terrestrial respiration and fire by 25.6 Gt/year, (b) an increase in ocean respiration by 23 Gt/year, (c) human fossil fuel and cement production emissions of 9.4 Gt/year, (d) land use change of 1.6 Gt/year,

minus

(e) an increase in terrestrial photosynthesis by 29 Gt/year, (f) an increase in ocean absorption and photosynthesis by 25.5 Gt/year.

The above increases (relative to 1750 AD), both in emissions and absorptions, result from increased temperature, as explained in the paper.

• demetriskoutsoyiannis,

You answered the first question wrongly, but you didn’t answer the second. You got your units wrong.

1. Human emissions are ~10 GtC, not 9.4 GtCO2 annually. Let’s use your numbers and correct your units to 9.4 GtC, of which 5.1 GtC is annually added to the atmosphere. That means human emissions causes an increase of 5.1*3.67/7.81= 2.4 ppm increase in CO2 concentrations annually.

2. You failed to answer this question. According to the carbon budget, both land and ocean are carbon sinks, so they take up more CO2 than they contribute to the atmosphere. You know that difference between the 9.4 and 5.1? That difference of 4.3 GtC is taken up by the land and oceans in roughly equal quantities, meaning the net contribution of land and ocean sources of CO2 to the atmosphere is 0 GtC.

Now how much does CO2 increase each year? Let’s use a 10 year average. In 2013, the annual average was 396.74 ppm. In 2022, it was 418.56. That means on average CO2 has increased by 2.2 ppm each year. If you use the correct units, we can see from your own admissions that humans are responsible for virtually all the increase in CO2.

• I wrote: “even though I am not sure if words can be better understood than geometric depictions”.

I must now rephrase it as: “even though I am sure that words cannot be better understood than geometric depictions”.

Hence, there is no meaning in continuing this exchange.

• The graphical depiction in the carbon budget make my point. The increase in atmospheric CO2 each year is 5.1 GtC entirely from human activity. It’s clear in the numbers:

1. Human flux: 1.6+9.4 = +11 GtC annually.
2. Land flux: +.1-.3-1.9-3.4+1.5 = -4 GtC annually.
3. Ocean flux: +.6-2.5 = -1.9 GtC annually.
Total: 5.1 GtC annually

Both land and oceans remove precisely the difference between our emissions and what remains in the atmosphere, so it must be that ~100% of increase in CO2 comes from human emissions. I can see why you’d conclude that “there is no meaning in continuing this exchange.” The numbers you shared from the IPCC and illustrated in your Figure A1 prove you wrong.

• You confirm that our numbers our correct, and you conclude that our correct numbers prove us wrong.

I conjecture that the logic behind your arithmetic is this. A tree, before taking a molecule in its photosynthesis, first examines its origin, whether it was emitted by land or ocean or humans, and uses it only in the first case (and likewise for the ocean).

• demetriskoutsoyiannis,

In your initial comment to me, your units were wrong, but the numbers with corrected units are correct. And yes, they prove you wrong. As you can easily see from these numbers, human emissions are ~2x the increase in concentrations with land and oceans taking up the difference between our emissions and the airborne fraction. This means necessarily that human activity is responsible for ~100% of the increase in CO2.

If you extend these numbers back to 1750 using values from the carbon budget, this doesn’t change. The natural carbon cycle is nearly balanced – it’s actually a bit of a net sink. It’s human emissions that flip the carbon cycle to a net source. So all the increase in CO2 comes from human activity.

I make this point using the 2021 carbon budget and 5 independent lines of reasoning and evidence.
https://woodromances.blogspot.com/2022/09/how-do-we-know-that-humans-are.html

Your conclusions require that human CO2 magically disappears and temperature creates CO2 magically in the same quantity as our emissions.

• An earlier comment admitted that the ice cores show CO2 changes lagging temperature changes, and admitted that datasets since 1980 show CO2 lagging. But then asserted that all the CO2 increase since 1850 is from humans.

Well, there’s good evidence LIA temps started rising before CO2.

https://rclutz.files.wordpress.com/2023/09/co2-and-temps-250-yr-lag-during-lia.png

• Ron, here is a paper that compares global temperature to CO2 from ice cores. You can’t use the temperature proxy from the ice cores because that reflects the local temperature where the ice is.

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993795

• “You confirm that our numbers our correct, and you conclude that our correct numbers prove us wrong.”
Once we correct the units in your comment, yes those numbers were correct and they prove the conclusions of your paper wrong. It cannot be that either the land and ocean are the source of the increase in CO2 because they are a net CO2 sink.

“I conjecture that the logic behind your arithmetic is this. A tree, before taking a molecule in its photosynthesis, first examines its origin, whether it was emitted by land or ocean or humans, and uses it only in the first case (and likewise for the ocean).”
No, that is not a conjecture behind the logic of my math. That may be a conjecture behind yours, but natural sinks don’t care about the origin of the CO2 molecules. What matters is that the natural cycle is a net sink and the human contribution is a net source.

For example, if you have an income of \$1000/week and your expenses are \$990/week, you can save \$10/week. But if someone has figured out a way to steal \$50/week from your account, you’re going in debt (or your savings are being depleted) by \$40/week. Why? Because someone is stealing your money. The theft is flipped your budget from being in the black to being in the red, and the weekly theft is 100% of the problem.

Likewise, human emissions are flipping the carbon cycle to a net source, and human emissions are 100% responsible for the increase in CO2. That’s what those numbers in your paper demonstrate.

• Christos Vournas

jim2,
“You can’t use the temperature proxy from the ice cores because that reflects the local temperature where the ice is.”

It is a very important conclusion. If it is locally cold enough, below the temperature of CO2 freezing point, CO2 will be heavily sequestered in ice.
Thus, the colder it was, the more CO2 in the ice cores.

https://www.cristos-vournas.com

• jim2, if you are referring to my LIA chart, note that the Moberg temperature series is a NH reconstruction, and that the Kouwenberg CO2 is a stomata series.

• We are considering the vast CO2 natural reservoirs (oceans and land), we are considering their vast CO2 content, along with the tiny ~400 ppm CO2 content in the actually very thin atmosphere.

At current average global temperature it is the ~400 ppm CO2 content which is in equilibrium interaction with the CO2 natural reservoirs. Or, to say diferently, at current average global temperature, the natural CO2 reservoirs with their mighty CO2 content “support” the ~400 ppm CO2 equilibrium content in earth’s atmosphere.

What we observe is that there is a rise in earth’s global temperature.
Also, it is measured, that there is an annual ~2 ppm CO2 content rise in earth’s atmosphere.
And, it is estimated, ~4 ppm CO2 content (as added amounts of CO2 from the fossil fuels burning) is annually added to the earth’s atmosphere.

So, we have, from the fossil fuels burning, annually added
~4 ppm CO2, but the annual rise of CO2 is ~ 2 ppm.

It is the 400 ppm which are actually being “supported” by natural reservoirs.
The average global temperature rise is the cause of that
~2 ppm CO2 rise in earth’s atmosphere, and not the fossil fuels burning.

Let’s discuss it arithmetically:

the current CO2 content of ~400 ppm is 100%
the ~2 ppm rise is then 0,5%
and the fossil fuels “contribution” is 1%

so, a layman’s logic, if we stop burning fossil fuels, there would not be the 1% “contribution”

so, if we suddenly stop burning fossil fuels, there will be a natural mitigation of ~0,5%.

So far, so good… in ten years there will be ~5% less CO2 content in earth’s atmosphere

in a hundred years there will be – the simple arithmetic cannot answer the question, because the simple arithmetic is very simple.

https://www.cristos-vournas.com

36. When I read a paper like this, I’m not seeking ‘truth’ or even trying to quantify uncertainty, i’m seeking to learn something. This paper has provoked me to think more deeply about causality in a complex system with feedbacks. That’s how I roll as a scientist. I don’t play ‘truth’ arbiter like the folks at realclimate

• Dr. Curry,

Again with all due respect, this is your blog, and of course you can do with it as you please, and I doubt anyone wants you to be a “truth arbiter.” But science does seem to have a lot to do with accurate assessments of what conclusions can be drawn from the available evidence, and what conclusions cannot be drawn. That is, science should be about understanding how the actual world operates and conveying that accurately and honestly. I would think that should have a lot to do with how “scientists roll.” This paper fails to account for the carbon budget. We know it’s conclusions can’t be drawn from the evidence, since human emissions roughly double the increase in atmospheric CO2 concentrations and land and ocean are net sinks. So this paper is wrong.

This blog has promoted several papers like this recently, and it gives the impression that you’ll promote just about any old thing that criticizes climate science, even if it’s fatally flawed and obviously wrong.

• MMM

The methodological problem of the paper is that they “used the mean (CMIP6 mean) of the output series of the Coupled Model Intercomparison Project (CMIP6) averaged over the globe” when testing causality in model world. But that isn’t at all parallel to their test of causality for Earth, which is more like testing a single instance of a model. Ask the authors to apply their causality approach to a single model run, and see what happens!

• MMM: If you read the paper before criticizing it, you would perhaps see this in section 3:

“To check whether the results of our methodology would change if we chose any particular member of the ensemble instead of the mean, we also retrieved outputs from a
single model, namely the UK Earth System Model (UKESM1 [21]). For the sake of brevity of this paper, we give this latter analysis (whose results eventually do not differ from those
of the CMIP6 mean) in the Supplementary Information”.

• MMM

I’m glad you did that calculation. However, in digging into the UKESM paper, I realized another problem with your model comparison… you need to pick an ESM that is emission driven, not concentration driven.

From the UKESM paper: “All of the results in section 4, and most of the simulations that will be submitted to CMIP6, are driven by CO2 concentrations rather than CO2 emissions”

If you don’t have a model with a dynamically coupled CO2 concentration, of course you won’t see temperature effects on CO2!

• Judith, I wish to express my special thanks to you, not only for posting our piece and your insightful comment on it, but also for teaching us the qualities that could make us real scientists:

“i’m seeking to learn something”

“provoked me to think more deeply”

“I don’t play ‘truth’ arbiter”

I, too, believe, humility goes hand-in-hand with knowledge.

You also wrote:

“Disagreement and debate is the spice of the climate blogosphere. We all stand to learn something.”

May I expand the first part: Disagreement and debate are the food of science. Its growth depends on them. (Like the growth of plants and the entire ecosystem depends on atmospheric CO2 :-)

More generally: «Tὸ ἀντίξουν συμφέρον καὶ ἐκ τῶν διαφερόντων καλλίστην ἁρμονίαν καὶ πάντα κατ’ ἔριν γίνεσθαι»
“Opposition unites, the finest harmony springs from difference, and all comes about by strife” (Heraclitus, Fragment B 8).

37. David Andrews

Dr. Curry,
Here is another perspective on truth. Science advances when original but wrong ideas are discarded because of empirical evidence. That is why science progresses better than, say, philosophy. I have yet to see a climate skeptic ever admit an error, and that is why you go around in circles: from Humlum to this paper for example. Truth matters. The alternative way science advances was stated by Planck: “one funeral at a time.”

• rtj1211

Mr/Dr/Prof Andrews. Science is likely to advance faster if a 30+ year gravytrain amounting to \$1bn+ of public funding were not wasted on ‘computer models’ which do not accurately represent how climate works, but are used to force a religious doctrine onto 7.5 billion people.

As a biologist, I can tell you that carbon dioxide is not a poison, it is the fundamental requirement for all photosynthesising organisms to exist. And without those photosynthesisers producing oxygen, all the respiring mammals wouldn’t exist. We as humans would never have existed without atmospheric carbon dioxide, and don’t you ever forget it.

You would also do well to realise that the rates of photosynthesis on earth, at constant temperatures, are higher as carbon dioxide concentrations rise (basic Michaelis-Menten enzyme kinetics). So if you want trees to grow faster, grass to grow lusher, global leaf area to increase, the quickest way to do that is to increase carbon dioxide in the atmosphere. It will be a self-regulating mechanism, because in the end the rate of photosynthesis will start to bring down the levels of carbon dioxide, which will reduce the maximum photosynthetic capability as well. Of course, that also depends on rainfall, atmospheric moisture remaining somewhat constant too, as water is the other key input to the photosynthetic reaction and plants in general will need sufficient water absorption to replace their loss via transpiration if they want to photosynthesise effectively.

Of course, if humans set about destroying soil to turn it dead by deforestation, by spraying poisons all over the earth, by killing aquatic wildlife through release of toxic chemicals etc etc, then this isn’t going to help photosynthetic capability, is it? But that’s got nothing to do with oil production, cars driving. It’s got to do with heavy industry not being appropriately regulated and it’s to do with forestry conglomerates thinking that only money matters.

The carbon dioxide fixation occurred when rebellious environmentalists decided they wanted to go mainstream and earn lots of money from ‘Big Green’.

38. Sorry to all, for some duplicates…
There were several attempts to post something without any direct response of publication, while others did appear directly. That was very confusing, as some (long) reactions seemed to disappear in cyberspace…

39. David Andrews

Demetris,
I still see no discussion by you of the question: have land/sea reservoirs been net sinks or sources in the industrial era? How does that effect your conclusion?

• “I still see no discussion by you of the question: have land/sea reservoirs been net sinks or sources in the industrial era?”

I thought it was obvious that they are net sinks, wasn’t it?

And that we, humans, are net emitters… Isn’t that obvious from our Fig. A1, also reproduced in this post?

But we are trying to see the entire system, which includes, as an essential part, humans (a species that I personally don’t wish to go extinct…). So, our conclusions are for the entire system.

• Demetris, if the main emitters are humans and both oceans and vegetation are sinks, the only conclusion can be that (near) all the increase of CO2 in the atmosphere is from human emissions. All other possible sinks and sources are much slower in exchange rate than these three sources (and sinks for oceans and vegetation).

Again, the problem is in the small +/- 3-4 ppmv/K natural variability which maximum result (Pinatubo, El Niño) is only +/- 1.5 ppmv around the 90+ ppmv trend since 1958:
You expand the results of the short-term variability to the trend itself, while variability and trend(s) have very different causes, except for a small contribution of warmer ocean temperatures…

Here the difference in slopes between the derivatives:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_der.jpg

Here for the period 1985-2000, with the 1991 Pinatubo and the 1998 El Niño for T and CO2:

• No, Ferdinand, it is not correct that “the main emitters are humans and both oceans and vegetation are sinks”. The humans emit 4%–they cannot be “the main emitters”. Rather, the “the main emitters” (responsible for 96%) are “oceans and vegetation”. And they are also sinks.

As a hydrologist and civil engineer, I have been familiar with several types of balances. It never made sense to me to isolate a part of the balance as if it were something autonomous and isolated from the other parts. As I wrote above, I always try to see the entire system.

• Demetris,

I should have included the word “net” sinks for oceans and vegetation…

In a balance you have two sides: incoming and outgoing data.

No matter how much natural carbon cycling is going on, as long as the increase in the atmosphere is smaller than the human contribution, only humans are responsible for the bulk of the increase. Even if the natural C cycle doubled or halved from one year to the next: the natural C cycle in the past 60+ years was always more sink than source.
That means that the natural C cycle can’t be the main source of the CO2 increase in the atmosphere: that is a net sink, not a net source…

If you have a lot of cycles, more or less in equilibrium and one additional one-way source, it is only that (even small) extra that causes the increase, not the bulk of the cycles.

BTW, even with 4-5% of the inputs, the current, measured (from the 13C/12C ratio), human contribution in the atmosphere is already around 10% and in the ocean surface around 6%. In vegetation more difficult to quantify.

• “a lot of cycles, more or less in equilibrium”

In my humble opinion, Nature hates “equilibrium” (like she hates vacuum) and never materializes it. Systems in equilibrium are dead systems. Change is the only rule in Nature–and this presupposes that a system is not at equilibrium.

See a toy example in my article: A random walk on water, http://dx.doi.org/10.5194/hess-14-585-2010

• Demetris, I said “more or less”, but still nature tries to get back to a dynamic (*) equilibrium with a speed that is directly proportional to the distance to that equilibrium:

The current CO2 level in the atmosphere would be around 295 ppmv for the current (area weighted) average ocean surface temperature.
The current uptake by oceans and vegetation is about 2% of the difference between actual CO2 level and the dynamic equilibrium with the ocean surface: 120 μatm (~ppmv) difference gives ~2.4 ppmv net sink rate.

The interesting thing is that the natural variability in sink rate (caused by temperature variability) is very small: about +/- 1.5 ppmv/year for the largest extremes, while natural fluxes are around 100 ppmv/year.

(*) dynamic: a lot of CO2 is released near the equator and absorbed near the poles to return with the THC waters about 1000 years later near the equator. If the average temperature or CO2 pressure changes, the process dynamics change to reduce the disturbance.

• Agnostic

Ferdinand Englbeen: “as long as the increase in the atmosphere is smaller than the human contribution, only humans are responsible for the bulk of the increase.”

This is fundamentally incorrect.

Currently humans contribute approx twice as much CO2 into the atmosphere than it is increasing by. That does NOT mean that humans are causing the CO2 in the atmosphere to increase. The system is out balance because the rate at which biota decays releasing CO2 and methane is faster than at the rate at which it can be fixed, regardless of our contribution.

Mans contribution can make more CO2 available and mean photosynthesis can happen more efficiently, but not linearly. There have been periods in the last 1000 years when CO2 levels have been comparable to today. Given they have not quite reached modern levels, it’s reasonable to argue that we have had an impact on the net increase. But it is not reasonable to argue that we have been responsible for the entire increase because on all other time scales the warming precedes CO2 increase and the mechanism for that is (I thought) well understood:

Processes that release CO2 are more temperature dependant than processes that fix it. When it warm and CO2 is released faster than it is fixed, then atmospheric CO2 increases.

• Joshua

Agnostic –

> because on all other time scales the warming precedes CO2 increase and the mechanism for that is (I thought) well understood.

What is the mechanism that explains the warming (an increase that’s directly proportional to anthropogenic CO2 emissions) if it’s not anthropogenic CO2 emissions?

• Joshua, that is merely a coincidence from the relative ratio of human and natural CO2 emissions currently. Skrable et al (2021) showed that despite an estimated 205 ppm of FF CO2 emitted since 1750, only 46.84 ppm (23%) of FF CO2 remains, while the other 77% is distributed into natural sinks/sources.

As of 2018 atmospheric CO2 was 405, of which 12% (47 ppm) originated from FF. And the other 88% (358 ppm) came from natural sources: 276 prior to 1750, and 82 ppm since. Natural CO2 sources/sinks continue to drive rising atmospheric CO2, presently at a rate of 2 to 1 over FF CO2.

https://rclutz.files.wordpress.com/2022/07/history-of-atm-co2-1.png

• Joshua

Ron –

If the rise in (non-anthropogenic) atmospheric CO2 is caused by warning (warning that just happens to be proportional to anthropogenic emissions), what has caused the warming?

• Joshua,

You asked: “If the rise in (non-anthropogenic) atmospheric CO2 is caused by warning (warning that just happens to be proportional to anthropogenic emissions), what has caused the warming?”

• Joshua, what warming proportional to human hydrocarbon emissions?
https://rclutz.files.wordpress.com/2023/02/uah-global-1995to202301-w-overlay.png

What we see is the sun and oceans doing their thing.

• Joshua

Ron. –

I guess I wasn’t clear.

There’s a decades-long, steady trend of temperature increase (you know the one that supposedly “paused”*) concurrent with a similar pattern of increase in anthropogenic CO2 emissions and accumulation of those emissions in the atmosphere.

Where is the similar trend of increase of some other forcing?

Hand-waving at oceans and the sun seems sub-optimal. If it’s not the anthropogenic CO2 that caused the warming, where is the signal in some other forcing (other than anthropogenic or even non-anthropogenic, atmospheric CO2) that caused the warming, that in turn putatively caused the rise in the non-anthropogenic, atmospheric CO2?

*It’s always interesting to me how “skeptics” say there was a “pause” in the warming and then say “Warming, what warming?”

• Joshua

If you’re going to go with “There isn’t a trend of warming,” then apparently you think Demetris’ theory is crap.

• Joshua

Robert –

Thanks for providing Yuri answer to my question.. So I guess I wasn’t so unclear after all. Sssms others have had unexplained trouble answering.

So, apparently you think the signal of the forcing is sunspots. Do you think there’s evidence of a correlation between sunspots and (lagging) increase in atmospheric CO2 in the past, where warming functions as the mediator variable?

• Joshua. Sunspots are not the forcing signal, they are a proxy for solar activity. The sunspot data is only accurate enough for my purposes back to about 1800, and my model uses more than 100 years of data (to deal with solar constraints), so predictions only are reliable back to about 1900.

My interest in Demetris’ result was that if solar activity is the primary driver as my empirical model suggests, then co2 doesn’t play a role, or it must at least lag temperature.

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993850

The results in my comment above confirm that temperature and co2 are coherent to some degree, and also confirm Demetris’ result that temperature leads co2 by 6 months — at least over the time scales for which we have measured co2 data.

Demetris

I ran the experiment again for NH and SH data with the same delay result as for global temperature. I also switched from a Hamming to a Flattop window just to make sure that window leakage wasn’t affecting results. Finally, I ran the experiment with ln(co2). That result is shown here.

https://localartist.org/media/CO2_Temp_FRF_ln_flat.png

• So Joshua, you want an answer to what caused the warming recovery after the LIA. Lots of research and theories for you to read and satisfy yourself. All we know for certain is that the LIA was not ended by warming from humans burning fossil fuels.

BTW Ronald can’t come out and play any more, he has work to do.

• Joshua

Robert –

> Joshua. Sunspots are not the forcing signal, they are a proxy for solar activity.

Well, that’s what the link you provided said. And it’s also what I meant when I described the casual chain with a mediator variable.

So I was asking you (and I guess the question still stands) about historical evidence where there’s an association between sunspot activity and (lagging) atmospheric CO2 (with an assumption of warming as the mediatorl.

• Joshua

IOW, proxy for solar activity and signal of forcing would be synonymous.

• Agnostic

Joshua: “What is the mechanism that explains the warming (an increase that’s directly proportional to anthropogenic CO2 emissions) if it’s not anthropogenic CO2 emissions?”

Firstly, why “directly proportional”? Human emissions and temperature do not correlate terribly well. The slight cooling from 1940-1970 occurred when emissions where increasing exponentially.

Secondly, the mechanism for warming is likely to be similar mechanisms that caused warming in the Minoan, Roman, Medieval warm periods, and their absence likely the reason for the cold periods especially the LIA. They are not well understood, but it is unlikely that it is because CO2 is a control knob.

The scope of the paper we are discussing is whether or not the causality is correct – that the CO2 CAUSED the recent warming. On all time scales, including short time scales, where we have good data, CO2 nearly ALWAYS lags temperature. So the causality cannot be that CO2 CAUSES temperature to increase. It’s the other way around. That does not mean that CO2 does not cause further warming – it’s a positive feedback.

• Joshua

Agnostic –

It’s interesting to see the high confidence you express in your opinions in this thread as it is my recollection from back in the day that you were more “agnostic” than how it appears here. That’s just an aside, and not directly relevant.

> Firstly, why “directly proportional”? Human emissions and temperature do not correlate terribly well. The slight cooling from 1940-1970 occurred when emissions where increasing exponentially.

Of course, I don’t really know the details very well, but it is my assumption that there is a general, directly proportional relationship. That doesn’t mean that there wasn’t “noise.” I don’t see “noise” as disproving a directly proportional correlation (even if that doesn’t prove causation). I’m talking along the lines of a relationship that would look like a dose-response relationship over decades (starting when anthropogenic emissions reached a critical threshold). My assumption is that people who study this wouldn’t for decade, identity such a proportional relationship, if none existed. And then there’s the critical aspect, imo, for identifying causality, which is that before the fact this relationship was projected and predicted.

> Secondly, the mechanism for warming is likely to be similar mechanisms that caused warming in the Minoan, Roman, Medieval warm periods, and their absence likely the reason for the cold periods especially the LIA. They are not well understood, but it is unlikely that it is because CO2 is a control knob.

So this is what I keep asking, and near as I can tell what i’m getting in return isn’t particularly convincing. The closest was a response that sunspot evidence indicates solar activity as the “cause” for the trend in warming, but when I asked for more information related to pin that down, I didn’t get any particularly convincing.

Of course, you wouldn’t need to convincingly identify a different cause of warming to disprove the theorized direction of causality between warming of unknown etiology and atmospheric CO2. But when there is such a compelling case made in advance, that has played out over such a long period of time, of a correlational relationship, it’s not particularly convincing to me when “disproof” is claimed without a more clear alternative explanation.

> On all time scales, including short time scales, where we have good data, CO2 nearly ALWAYS lags temperature. So the causality cannot be that CO2 CAUSES temperature to increase. It’s the other way around.

So I see you repeat. And I see technical responses being repeated. And so I see people making technical arguments I can’t evaluate. That leaves me at the place of trying to evaluate probabilities, from indirect evidence. On the one hand, I see a minority of people, some anonymous, some with no known quantity of domain relevant expertise, some with seemingly adjacent domain relevant expertise, some with directly applicable domain relevant expertise, arguing that a phenomenon long ago predicted, that played out over decades, has been completely misunderstood by a majority of people with varying levels of domain relevant expertise, but most significantly the vast majority of people with the most domain relevant expertise.

It doesn’t help when Demetris backs up his arguments about the probabilities by arguing that beliefs long-held by people without modern analytical tools being eventually disproven, as compared to decades of confirmation of a belief done by people with the most modern of analytical tools, strengthens his argument.

> That does not mean that CO2 does not cause further warming – it’s a positive feedback.

Well, that is also problematic, IMO. It looks a bit to me like people saying that they don’t doubt the GHE, but nonetheless there’s been a “pause in global warming” even though there’s been no pause in anthropogenic CO2 emissions.

• David Appell

Agnostic commented:
There have been periods in the last 1000 years when CO2 levels have been comparable to today.

Really? When?

• Jim2, here are the data from the Vostok ice core for the last start of new glaciation (the end of the Eemian, about 130,000 years ago), where methane clearly follows the temperature decrease, but CO2 stays high for thousands of years and only starts declining when temperature reached a new minimum and land ice a new maximum:
http://www.ferdinand-engelbeen.be/klimaat/eemian.html

The point that methane follows closely the temperature change and CO2 does not, proves that the lag of CO2 isn’t an artifact of dating problems for ice vs. gas in the ice core, because both are from the same enclosed gas bubbles.

The subsequent drop of 40 ppmv CO2 had no clear effect on temperature or land ice formation, that points to a low to al low influence of CO2 on temperature…

Further, the snow that falls on the center of Antarctica, including Vostok, originated from near all the SH oceans, be it condensing to snow near Antarctica. Even so, it reflects far more than “local” temperatures.
For coastal ice cores, that is snow originating from nearby oceans waters…

• How do you explain the contrary evidence presented by the paper I linked?

• jim2, your link goes to Shakun et al. (2012). At the time many took issue with it. Don Easterbrook raised many questions about it here:
https://wattsupwiththat.com/2012/04/08/did-shakun-et-al-really-prove-that-co2-precede-late-glacial-warming-part-1/

I’ve no axe to grind, but the paper may not prove what it claims.

• Noted.

40. thecliffclavenoffinance

I want to thank Ms. Curry for allowing my prior comment, very critical of this article and her choice to include it here. Some conservative websites would have made a similar comment “disappear”.

I want to thank Mr. Engelbeen, especially, and Mr. Simmons for their excellent comments, making these comments worth reading, even though the article was not. With editing, Mr. Engelbeen’s combined comments would make a great article.

Those two commenters were very polite to Ms. Curry for allowing this article on her website. Fortunately, I did not inherit the polite gene.

Ms. Curry acts as the editor of this website. It is her job to read and evaluate articles before inflicting them on visitors.

I am the editor of a climate and energy blog where I list 30 conservative articles worth reading each day — half of them on climate and energy.

I do not have to agree with any author, but they must sound like they know what they are talking about, or MY own reputation is trash. That’s why this article would never qualify for my blog, and allowing it here tarnishes the reputation of Ms. Curry.

In my opinion, this website has devolved into a variety of real climate science articles and science denying articles like this one.

That is the result of bad editing, and bad editing has consequences. For one example, I’ve deleted this website from my climate and energy website Bookmarks list.

• Stephen Segrest

• How lucky we are to have someone commenting here and passing judgment on my blog, who is so much smarter than Koutsayiannis (not to mention myself)

Demetris Koutsoyiannis is professor of Hydrology and Analysis of Hydrosystems in the National Technical University of Athens. He has served as Dean of the School of Civil Engineering, Head of the Department of Water Resources and Environmental Engineering, and Head of the Laboratory of Hydrology and Water Resources Development. He was Editor of Hydrological Sciences Journal for 12 years (2006-18), and member of the editorial boards of Hydrology and Earth System Sciences, Journal of Hydrology, Water Resources Research, Hydrology and Sci. He has been awarded the International Hydrology Prize– Dooge medal (2014) by the International Association of Hydrological Sciences (IAHS), UNESCO and World Meteorological Organization (WMO), and the Henry Darcy Medal (2009) by the European Geosciences Union (EGU). His distinctions include the Lorenz Lecture of the American Geophysical Union (AGU) (San Francisco, USA, 2014) and the Union Plenary Lecture of the International Union of Geodesy and Geophysics (IUGG) (Melbourne, Australia, 2011). He has served as professor of Hydraulics at the Hellenic Army’s Postgraduate School of Technical Education of Officers Engineers (Athens, 2007-10). He has been visiting academic/professor at the Imperial College (London, 1999-2000), Hydrologic Research Center (San Diego, 2005), Georgia Institute of Technology (Atlanta, 2005-06), University of Bologna (2006 & 2019) and Sapienza University of Rome (2008 & 2019).

• Joshua

Careful Judith. If there’s one thing that “skeptics” hate, it’s an appeal to authority. I’m sure there will be massive incoming any second now. Please take cover.

• thecliffclavenoffinance

“How lucky we are to have someone commenting here and passing judgment on my blog,”

Thank you for the complement, Ms. Curry: Being honest, without self censorship, is the first step to winning the climate change “battle”.

You are lucky to have more than one commenter who point out that an article by a Professor contradicts the basic climate science consensus ( I estimate a 99.9% consensus) that humans have added a lot of CO2 to the atmosphere.

And I added that a Ph.D. Editor seems to believe the diversity of opinion should include a junk climate science article, while I completely reject junk science as the editor of my own blog (with over 630,000 page views, by the way).

You are lucky that a reader named Mr. Engelbeen spent a lot of time very effectively refuting the article.

The Appeal to Authority logical fallacy you just invoked to defend the author is worthless. It is the Appeal to Authority logical fallacy that is frequently used to defend the climate science consensus — the IPCC predictions of climate doom — and I don’t go for that.

• My providing DK’s credentials is not an appeal to authority. I am willing to given anyone with credible credentials a a peer reviewed publication an opportunity to have their paper discussed here, provided it is on a topic that I regard as relevant.

I also provide opportunities for people with no credentials, and that I have no familiarity with, to publish articles here. I am far more selective of such articles (many are submitted to me each week); many have turned out to be excellent contributions and collectively have contributed to several books being written by these authors.

In reading the comments, i do not regard anyone to have stated the irrefutable final word on this issue.

• Dear Judith,

My experience with fierce discussions with extreme smart people like Salby, Berry, Harde and several others with a lot of academic titles is that they have a lot of trouble to understand simple things like a household budget or a mass balance…

The basic error in professor Koutsoyiannis work is quite obvious at a very basic level:

If you have a one-way source that delivers twice the amount of CO2 as the increase in the atmosphere, then that is the main cause of the increase, no matter how much the other sources / sinks do circulate over the atmosphere. The other sources are net sinks that remove CO2 out of the atmosphere and can’t be the cause of the increase.

No calculation or graph or assumption or model on this world can beat that fact.

• The post has attracted a lot of comments and some useful back and forth that has helped me understand the issues. People who have no scientific skill set sometimes seem a little bit uncomfortable with the discussion and resort to unscientific “consistency” arguments.

• Joshua, Your selectivity and bias are very obvious. You I believe have a personal and unhealthy obsession with Judith Curry who is a fine scientist and a believer in open intellectual discussions. You should find a more productive use of your time. There must be other people in your life.

In fact you have a decades long track record here of posting long winded word salads with no technical or scientific content, misrepresenting what others say, and generally obstructing constructive dialogue with your trivia and personal attacks. This is what has gotten you banned at other blogs like Lucia’s.

• Dr. Curry,

I think it may be pretty obvious that you should know you’re in trouble when you can’t defend the conclusions of the paper, so you resort to just listing the credentials of the authors. Those of us following the discussion in the comments have asked Demetris Koutsoyiannis several questions to clarify points in his paper, and he can’t answer them satisfactorily. In fact, data he included in his own paper, which he took from the IPCC, show that the carbon budget only balances if virtually all the increase in CO2 comes from human activity.

I’m not sure how a paper that includes its own refutation gets past peer review or why this paper would get selected for promotion here from among all the other papers getting published today that don’t refute themselves. It’s your blog, obviously, and you can do what you want, but this is a bit of a head scratcher.

• Joshua

Judith –

This is just silly. Why do you delete my comments for merely stating the obvious? Should I cry about CENORSHIP! and FREE SPEECH! Are you really that sensitive that you can’t handle a critical viewpoint? Are you really that worried that someone might read a view critical of what you say on your website? Bizarre. Aren’t you a big fan of FREE SPEECH?

Of course you appealed to Demetris’ authority (credentials and qualifications).

There’s nothing inherently fallacious about listing someone’s credentials as a way of reinforcing the validity of their analysis, but that doesn’t changed that you appealed to Demetris’ credentials as a way to reinforce the quality of his.

People can decide for themselves whether your appeal to Denetris’ credentials (authority) was fallacious but you should try to be consistent in your arguments.

If I appealed to Gavin’s credentials as a way to reinforce his disaagreement with Demetris, the cries of outrage would be fast and furious here in your blog.

• Joshua, You need to be self aware. The reason his credentials are relevant is that you have no credentials and have never made a single comment with any technical or scientific content. In short, you are a non-scientist politically motivated hack who has no credibility. You are like a mouse biting the toe of an elephant.

• Demetris, first, thanks as always for a most fascinating post.

A question. You say:

To deal with dependence in time, often manifested in high autocorrelation of the processes, we proposed the differencing of the time series, which substantially decreases the autocorrelation. In other words, instead of investigating the processes X and Y and find spurious results (as has been the case in several earlier studies), we study the changes thereof in time, ΔX and ΔY.

Gaussian random numbers have no autocorrelation. They don’t depend on what happened before. As a result, their Hurst exponents are ~ 0.5.

Natural datasets, like say average TOA solar reflection, global surface temperature, or average cloud height, do indeed tend to have high autocorrelation. Respectively, the Hurst exponents of those three are 0.71, 0.87, and 0.78 (CERES data).

However, differencing those time series leads to negative correlation. Respectively, the Hurst exponents of the differences of those three are 0.05, 0.22, and 0.11.

If, as you say, “high autocorrelation” (Hurst exponents >> 0.5) causes “spurious results”, wouldn’t negative autocorrelation (Hurst exponents << 0.5) also cause spurious results?

Serious question …

And Dr. Judith, thanks as always for all you do.

w.

• Thanks very much, Willis, and nice to hear from you. I will try to reply your question, adding some explanations.

In correlation between two different variables, there is a type of (anti)symmetry. Multiply one of the two by -1, and you have a couple of positively correlated variables. So what we infer for positively correlated variables (e.g. confidence limits) holds also for negatively correlated.

But when we go to AUTOcorrelation, things are fundamentally different. For instance, multiplying a series by -1, you again get a positively autocorrelated series.

A positively autocorrelated series results in increasingly high uncertainty as the Hurst coefficient is increasing (for large time scales). Hence, large Hurst coefficients affect seriously statistical inference.

On the contrary, Hurst coefficients < 0.5 make the uncertainty smaller than in a purely random process.

So, the reply to your question "wouldn’t negative autocorrelation (Hurst exponents << 0.5) also cause spurious results?" is categorically NO.

• For further information, you may google my book “Stochastics of Hydroclimatic Extremes – A Cool Look at Risk” and download it — it’s in open access. In particular, see “Digression 3.B: What is dependence in time?” and “Digression 6.J: Does periodicity affect estimation of K-moments?”, Note, negative autocorrelation, else antipersistence, is typically regarded as “quasi-periodicity”–and what is written in Digression 6.J is also valid for negatively autocorrelated processes. The Figure in Digression 3.B may help understanding why negative autocorrelation decreases uncertainty and bias as the time scale increases.

• Thanks, Demetris, much appreciated.

w.

41. I’m impressed by your humility — even in the obvious absence of the politeness gene.

42. Equation 9 is very problematic, it is a big assumption replacing the long term human contribution via fossil fuels with a bunch of guessed at parameters that appear by magic.

It suggests that CO2 levels will collapse to zero if the temperature drops below 285K, it also suggests CO2 levels will race away if the temperature rises appreciably over 285K. There is not enough analysis or support given for equation 9.

(Furthermore 5 fitted parameters in equation 10 is not parsimonious!)

I’m finding it hard to get past the criticism that you have identified a trailing causality to temperature in the seasonal aspect of CO2 fluctuation, and this does not extrapolate to the long term trend.

• James,

Equation (9) is just curve fitting without any physical base…
There is no process on this earth that can deliver 110-120 ppmv CO2/K into the atmosphere.

One can fit the same observed Mauna Loa curve as a simple factor of human emissions, which then is a real cause/effect, but even so just a matter of coincidence:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_cur.jpg

The coincidence is in the fact that human emissions increased linear each year, leading to a slightly quadratic increase in emissions, a similar increase in CO2 level and therefore a similar net sink rate increase.

That makes that there is a rather fixed ratio between increase in the atmosphere and human emissions around 50-55%.

If humans would halve their emissions, the net result in the atmosphere would be some variability around zero trend of CO2.

43. William Van Brunt

I have yet to read one paper that proves, applying the published data and thermodynamic principles that the increase in CO2 is the cause the driver of global warming.

Without this, the results of computer model are meaningless. In fact when applied in hindsight and compared to the the average global temperature record since 1880, the differences in outcomes of these models is of the order of 1 (K), the total increase since the early seventies, thus, proving that they are meaningless.

All I have seen is hypotheses and conjecture that since both the average global temperature and the atmospheric concentration of CO2 have risen since the early seventies, therefore, the increasing concentration of CO2 is the driver of the increasing global temperature.

Notwithstanding billions having been spent on the study and research, the tens of thousands of minds brought to bear on this topic, a whole industry arising related to this topic, this has been the state of play for the last 30 years. By now, the clear inference is that the increasing concentration of CO2 cannot be the cause of the increases global temperature.

• fizzy

“All I have seen is hypotheses and conjecture that since both the average global temperature and the atmospheric concentration of CO2 have risen since the early seventies, therefore, the increasing concentration of CO2 is the driver of the increasing global temperature.”

• William Van Brunt

My comment starts out with the statement “I have yet to read one paper that proves, applying the published data and thermodynamic principles that the increase in CO2 is the cause, the driver of global warming.”

Proof requires the application of physics to the data on changes in the concentration of CO2 to show that the results match the temperature record.

Well, yes, I know that Arrhenius did not prove “that the increase in CO2 is the cause, the driver of global warming”.

If you believe that you can prove, not assume or hypothesize, but prove that, “applying the published data and thermodynamic principles that the increase in CO2 is the cause, the driver of global warming”, please set out this proof.

• fizzy

OK, you want ‘proof’; I’ll settle for the overwhelming consilience of evidence.

44. William Van Brunt

The same result is reached when, upon the realization that there is a gaping whole left as a result of the fact that the science cannot prove that the increasing concentration of CO2 alone is the cause of global warming, (an increase of 1(K), requires an increase in heating of 8 w m-2 and the maximum theoretical increase in heating that the 80 ppmv increase in the concentration of CO2 over this period could provide is 1 w m-2 ) requiring the development of wholly unproven assumptions about the positive feedback or multiplier effects of water vapor on the heating of the planet due to the increases in evaporation driven by the increase in the concentration of CO2.

Again, there are no thermodynamic principles set out to support any of these assumptions.

45. William Van Brunt

Given that the increasing concentration of CO2 is not the cause of global warming, the debate set out in these comments about the cause or sources of this net increase in the concentration of CO2 and humanity’s contribution to the increase is …..irrelevant.

46. fizzy

Perhaps I’ve missed it among the 170+ comments here, but has no one mentioned the isotopic evidence?

The concomitant decrease in atmospheric O2 with increase in CO2 indicates that carbonaceous material is burning.
The concomitant decrease in atmospheric 13C with increase in CO2 indicates that the carbonaceous material is plants.
The concomitant decrease in atmospheric 14C with increase in CO2 indicates that the plants are ancient (fossil).

This evidence, along with the mass balance arguments, unequivocally establish that the dominant source of the current increase in atmospheric CO2 is fossil fuels.

I suppose this could be regarded as a ‘feedback’ from increasing temperature if we were burning all that coal and oil to pump up the air conditioning :-)

47. William Van Brunt

Moreover, I note, that the focus on global warming has for the most part ignored the massive threat posed by the growth in catastrophic weather, the devastation from which has increased tenfold over this period.

The growing, but still rather limited number of comments on this massive increase in the devastation wrought by catastrophic weather in general opine that, yes, the weather has worsened and go on to state as it were a fact, that this is the result of global warming, offering no proof that and a total failure to explain how, a 0.6% increase in absolute land temperature and a 2% increase in the heating power of land since 1972 can account for the 1,400% increase in near term devastation over this period.

This is the real, massive and immediate existential threat posed by climate change.

48. Strikes me I do not even recall any major fossil fuel companies (coal or oil) or industry organizations suggesting CO2 increase was not caused by fossil fuels. Very rough generalization- coal industry (decades ago) felt global warming was not bad, whereas oil industry focus (decades ago) was on disputing T rise as result.

49. I put here my reply to the comment by Robert Cutler, https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993850 , as the structure of the discussion has been perplexed due to the large number (> 200) of comments.

Robert, I really thank you for your effort to find this results and for your comment presenting them. This is really constructive.

I fully understand that you “have concerns about the method” that we developed. This is a normal reaction for newly proposed methods, and, I would say, it is a healthy reaction, because new methods should be scrutinized.

Please allow me to say that, what you call “potential pitfalls of the method”, in our view are strong points. As we write in our post: “A final prominent characteristic of our method is its simplicity. It uses the data per se, rather than involved transformations thereof such as the cross- and auto-correlation functions or their Fourier transforms —the power spectra and cross-spectra. The results are thus more reliable and easier to interpret.” (I hope the graph in the quiz illustrates that.)

Anyhow, I am very glad that your spectral method (despite its pitfalls :-) confirmed our results for frequencies below 1 Year^-1 (period / timescale above 1 year). As you can see in our Table 1, we found somewhat higher lags, up to ~1 year for increased time scales up to 16 years. But this is a minor detail, explainable by the different methodology and the different temperature data set. What is important for causality, in my view, is temporal precedence.

50. This is my reply to Judith Curry’s comment, https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993831

Thank you so much, Judith, for noticing my CV and presenting my credentials here. To dispel fears that were expressed after your comment, I can reassure them that my humble self is not an authority. Just I was lucky in some respects, in my professional career.

First, being a Greek, I got in contact with ancient Greek thought since my childhood, which was crucial in understanding what science, the scientific method, and their philosophical foundations are. For instance, σαφήνεια (saphenia, hastily translated as clarity), logic, stochastics, climate are concepts founded by ancient Greek thinkers (in my book, in open access in https://www.itia.ntua.gr/2000/, I devote some Digressions to explain these terms and their history).

Second, it happened to become a professional civil engineer and hydrologist. The former helped me to be in continuous contact with reality and be conscious of the risks when I depart from it, as well as to appreciate the value of data vs model outputs. The latter helped me to appreciate the huge uncertainty in Nature and avoid naïve and dangerous deterministic thinking and deterministic approaches.

Third, I was lucky that my colleagues recognized my work and rewarded me.

All these are coincidences as far as my humble self is concerned, who is not an authority. But in a sense I feel some pride to mention here that the greatest authority in explaining Earth’s climate, Milutin Milankovitch, was a civil engineer. Also, an authority in hydrology, Harold Edwin Hurst (whose contribution in understanding uncertainty in climate is most essential, even though, sadly, is not well known to climatologists) was a hydrologist.

51. One of the important qualities we learn in civil engineering is the respect of time frames and time limits (e.g. all projects have deadlines whose violation destroys you). Another one is the importance of assessing cost vs. benefit. A third one is effectiveness. All these preclude endless processes and even more so endless repetitions of same things.

In this respect, I wish to summarize here my impressions from this discussion.

First, I am glad that all did well with our quiz. Nobody refuted the fact that the data we present show time precedence of temperature changes over [CO2] changes. Moreover, some confirmed our result independently by additional graphs and different analyses. What was questioned is the time scale of the validity of our findings. We insist that this is at least a couple of decades and could be found longer if we had longer data sets–but we don’t. After all, the paleoclimatic data confirm the same causality direction for very large time scales. Is there a mechanism that, at intermediate time scales, magically reverses directionality? Perhaps, but no analysis has shown that. So, I look forward to seeing scientific papers showing the reversal of directionality at intermediate scales. I mean, showing that, based on data and not on imagination and models full of assumptions.

Second, I am glad that our graph on carbon balance, while initially found wrong by some, was eventually confirmed by the same. The graph clearly shows that, in comparison to what happened in 1750, now there are additional emissions of 59.6 Gt C/year, of which 9.4 Gt C/year are due to fossil fuel combustion. (Nb., in a comment above I incorrectly wrote Gt CO2/year; the correct is Gt C/year as correctly shown in the Figure). Even without considering the emissions from fossil fuels, there is a surplus of 50.2 Gt C/year with respect to the 1750 rate. The temperature rise explains this surplus, as shown in our calculations in Appendix 1. The counterarguments presented here, which are based on isolating the total balance into three parts, as well as on the emphasis on that we, humans, are net emitters, do not make sense in my humble view. The Earth works as a whole, includes us in its dynamics, but even before we existed as a species, the Earth used to change the CO2 in the atmosphere by more than an order of magnitude.

Third, nobody presented any argument against our important finding that climate models suggest a causality direction opposite to the real one. Perhaps this should be worrying. Even those who refuse the large-scale applicability of time precedence, but accept the short-scale one (which no one refuted), perhaps could worry. I think this was not discussed in literature before, so I look forward to seeing more scientific papers investigating this issue.

Fourth, I am glad that, by invoking “misinformation” and by suggesting punishment of Judith Curry (deleting her website, etc.) because she hosted our article, some commenters unveiled their real motivation. This is consistent with political agendas which aim to suppress freedom of opinion, expression and scientific inquiry. And here I shall repeat for a second time a part of Carl Sagan’s quotation: “The suppression of uncomfortable ideas may be common in religion and politics, but it is not the path to knowledge”.

All these increased my confidence that we have done our duty as scientists by doing this (fully unfunded) research and by presenting these findings, which are correct and important.

There are a lot of other impressions that are negative and made me sad, but I preferred to focus on those which made me glad.

• demetris

“ .. by invoking “misinformation” and by suggesting punishment of Judith Curry (deleting her website, etc.) ..”

This appallingly anti science mentality is ubiquitous in climate science and among its AGW proponents. It’s the only reason I began to research the issue in more depth a decade ago after having accepted the establishment narrative beginning in the 80s.

I applaud your efforts and courage to challenge the orthodoxy. Having the bravery to face a full frontal assault shouldn’t be part of the equation in contemporary climate science, but that is how the dialogue has devolved.

Keep on being a true scientist. History will remember those who are.

• Dear Demetris,

Some reaction of mine did not appear, so I fear that you haven’t understood the main problems with your work…

Nobody disputes that temperature variability is the main driver for the year by year CO2 variability around the increase. That is not the point of discussion.

The main problem is that you assume that the short-term CO2 lag over T of the variability (3-4 ppmv/K) around the trend shows that temperature also drives the 90 ppmv trend of CO2 (120 ppmv/K) over the past 60+ years.

That is physically impossible.

Moreover, the observed variability is the variability in net sink rate (not net source rate!) in oceans and vegetation, thus increasingly negative (!), while the CO2 trend in the atmosphere is going up.

In the upper graph, human emissions and measured increase are plotted, together with the calculated increase of CO2 in the atmosphere, based on the formula of Takahashi for the ocean surface temperatures (based on hundred thousands of seawater samples):
∂ln pCO2/∂T=0.0423/K
The difference between the observed CO2 increase and the sea water pCO2 is what drives the net uptake of CO2 into the oceans

Next part 2.

• “Nobody disputes that temperature variability is the main driver for the year by year CO2 variability around the increase.”

I dispute it. Temperature controls the seasonal ramp-up phase, but the draw-down phase is driven by photosynthesis, which operates over a large range of temperatures.

• “Moreover, the observed variability is the variability in net sink rate (not net source rate!) in oceans and vegetation, …”

Not so! See particularly Figure 3, and note how the warm 2015-16 El Nino year significantly increased the slope and peak of the ramp-up phase. The draw-down phases are unremarkable in their similarity.
https://wattsupwiththat.com/2021/06/11/contribution-of-anthropogenic-co2-emissions-to-changes-in-atmospheric-concentrations/

• Part 2…

The second graph shows the net sink rate caused by the CO2 pressure difference (ΔpCO2) between the atmosphere and the ocean surface (including vegetation, where pCO2 measurements are very difficult). That shows an increasing net sink rate in oceans and vegetation, where the variability around the trend is entirely caused by temperature variability, but the trend is entirely caused by the increasing CO2 pressure in the atmosphere.

Thus indeed, temperature variability modifies the net sink rate, but hardly influences the trend itself, as that depends of the huge CO2 increase in the atmosphere minus a small influence of warmer ocean temperatures.

Your assumption that temperature is the main driver for the CO2 increase in the atmosphere hereby is falsified.

The third graph is the calculated e-fold decay rate for any extra CO2 above equilibrium, not of interest here, but used in discussions with others about the speed of removal of our emissions (as mass: residence time vs. Bern model, both are wrong…).

Further, you still have not answered the basic questions from Mr. Simmons and others and me about the question where human emissions go if temperature/nature was the main driver and where in nature that extra (net) source could be.

That e.g. the carbon cycle in vegetation increased is true, but that is an increasing net sink, not a net source. Looking only at the increase in input(s) is not what one calls a “balance”…

If there was another net extra source, then the increase in the atmosphere would be larger than of human emissions alone…

• Joshua

Demetris –

> Further, you still have not answered the basic questions from Mr. Simmons and others and me about the question where human emissions go if temperature/nature was the main driver and where in nature that extra (net) source could be.

I was looking to see you address that issue. It does seem pretty fundamental to your analysis. I would think you must have already addressed it and I missed it? Perhaps it’s addressed by your statements that human emissions are only 4% of total emissions (and the driving effect of non-human emissions effectively swamp any GHE effect human emissions might have)?

At any rate, could you point to where you already answered this or hopefully, answer it again in simple language a non-expert could understand?

• Joshua,
I have spoken to the issue of the overlooked sources. Ferdinand has not addressed it. Apparently you also are reading comments selectively.

• Joshua

Clyde –

I’m not sure that would substitute for Demetris answering the question but itt would be a start.

• Clyde, i may have missed your question of “overlooked sources”, but in fact that is completely irrelevant: we don’t need to know anything of any natural source or sink to know the overall performance of all sources and sinks together.

We know human emissions: 5 ppmv +/- 0.25 ppmv per year
We know the increase in the atmosphere: 2.4 +/- 0.2 ppmv
The performance of all natural in/out fluxes then is -2.6 +/- 0.45 ppmv per year. The margin error is probable smaller, but forgot how to calculate a multiple error propagation…

• “…, we don’t need to know anything of any natural source or sink to know the overall performance of all sources and sinks together.”

What you are essentially saying is that it does not matter whether the natural fluxes are large or small. The only thing that matters is that the annual increase is about half the anthro’ emissions. I’m afraid I can’t buy that.

• Joshua

Spencer –

Let me see if I understand you correctly. And since I’m not entirely sure what you believe, and I can’t see where Demetris answers certain questions (or can’t understand what he said when he did so) I’ll ask you some questions to hopefully clarify your view and hopefully where it converges or diverges with his theory.

You believe that natural emissions of atmospheric CO2 have increased (more or less) contemporaneously or lagging behind a proportional increase in atmospheric (and presumably ocean) temperatures, and that the increase in atmospheric CO2 is explained by temperature increase. Thus, any warming effect of anthropogenic CO2 emissions is negligible. Is that correct?

So then, what do you think happens to the anthropogenic emissions? Is it just that the warming effect of those emissions is negligible because they are so small compared to the increased atmospheric CO2 emitted from other sources?

And what is it that’s causing the warming? Just natural cycles that haven’t yet been identified? Would you just ssy “unknown” and that it lies beyond the scope of your view to determine a cause?

• Joshua

Oops, sorry. I meant Clyde.

• michael haarig

I think you misunderstood “deleting her website”. It was only one commentator who deleted the link to JC’s side on HIS blog from the bookmark list.

52. Joshua

Demetris –

It is interesting how often you suggest you’re only a medium, and it’s the data which are speaking. Seems to me that you’re the one speaking about your interpretation of the data. When you say it’s merely the data speaking, and deemphasize that it’s you that are collecting and interpreting the data, then you are effectively making an unfalsifiable (and self-sealing) argument.

https://diagrammonkey.wordpress.com/2023/09/28/let-the-datas-speek/

• This is totally irrelevant to the scientific issues Joshua. Why don’t you address the science instead of vague and fallacious irrelevancies.

• Joshua,
Your summary of my position is essentially correct. Warming started about 20,000 years ago, and then accelerated about 12,000 years ago. Ocean levels have been increasing almost linearly for about the last 7,000 years, despite warming and cooling episodes. Milankovitch cycles seem to be playing the long game, being modulated by volcanic aerosols. Although, the Maunder Minimum may have reduced insolation for a long time, with the Earth still trying to get back to where it was before sunspots took an extended vacation.
There is a huge reservoir of organic material sequestered in the Tundra, which is releasing CO2/CH4 as it melts, through bacterial decomposition. Also, increased photosynthesis is allowing an increase in global biomass, which means that the annual ramp-up phase of CO2 is growing because the bacteria have more to work with. The ramp-up and draw-down seasonal phases are not symmetrical, with photosynthesis not being able to re-capture all the CO2 emitted in previous Winters. Given enough time, the system may equilibrate, but is currently in a transition state.

• David Appell

clydehspencer wrote:
Ocean levels have been increasing almost linearly for about the last 7,000 year

Sea level rose only about 1 m in the 5000 yr prior to the industrial era. An average of 0.2 mm/yr.

https://en.wikipedia.org/wiki/Early_Holocene_sea_level_rise#/media/File:Post-Glacial_Sea_Level.png

Sea level is now rising at 4+ mm/yr, over 20 times faster.

• “Sea level is now rising at 4+ mm/yr, over 20 times faster.”

Looking at high temporal resolution sea level for recent times shows that there have been events similarly showing high rates. However, they have declined. It is the same old story of the trend being modulated by ‘noise.’ There is no way of being certain that the current high trend will continue. Past behavior suggests that it won’t.

• David Appell

clydehspencer wrote:
Looking at high temporal resolution sea level for recent times shows that there have been events similarly showing high rates.

When?

There is no way of being certain that the current high trend will continue. Past behavior suggests that it won’t.

No decline in sight. Fundamental physics says there is none in sight. But yet, in 50 years rabbits might rule the world.

• Appell

With so much data and so many conclusions pointing to much lower future SLR than feared, it’s time to be cautious rather than rash in our public policy choices.

Acceleration found in these papers, 0.018mm/yr2, Kleinherenbrink 2019; 0.00007/yr2, Parker 2019; 0.009mm/yr2, Church 2011; 0.0042mm/yr2, Wenzel 2014; 0.0128mm/yr2, Houston 2021.

AGW fingerprint too small, errors 2-3mm/yr hemispheric scale Palanisamy 2015. Acceleration hardly detectable Meyssignac 2012. Not significantly different from zero Watson, 2019. Much reduced acceleration, Kleinherenbrink 2019. Negligible acceleration, Boretti 2020. Acceleration uncertainty 0.062, Prandi 2021

53. William Van Brunt

Having been at this since attending the celebration of the award of the Nobel Peace Prize to Gore and the IPCC, in 2007, in OSLO, when listening to what wasn’t being said and then doing back of the envelope thermodynamics, I realized that I had been totally taken in by the CO2 is the problem mantra and it is not.

It has taken me over 18,000 hours of independent study to both confirm that and to come to understand what the driver of climate change, both global warming and the real threat, the incredible rate of growth of truly massive catastrophic weather, is….It is the increasing global concentration, 11% global average, from ‘72 to date, of water vapor. This I can prove.

The published data and physics totally support the conclusions set out by Drs. Koutsoyiannis, Onof, Kundzewicz and Christofides and show how climate change, both global warming and the growth of truly massive catastrophic weather can both be limited and best of all, reversed.

On this journey I also came to understand how ridiculously incompetent, many of the climate and CO2 deniers were and naïve, incompetent, ignorant or, while I would like to think not, possibly, conspiratorial, cowardly and callously adherent to the mantra of CO2, many of the faithful for the CO2 is the problem hypothesis, were, (some of the foregoing comments confirm this), notwithstanding the growing massive and truly existential threat of climate change. This is geocentric type thinking of a volume and breadth I would never have dreamt possible.

There are exceptions to this, of course, but I have come across very few.

The only expert I have come across, until now, as knowledgeable, objective and willing to take a stand is the brilliant, courageous Dr. Cook….Dr. Cook, thank you, and now Drs. Koutsoyiannis, Onof, Kundzewicz and Christofides, who luckily all write well and with whom, this 79 year old former rocket scientist and retired lawyer, would love to collaborate.

Sagan could not be more correct – “The suppression of uncomfortable ideas may be common in religion and politics, but it is not the path to knowledge”.

• thecliffclavenoffinance

Mr. Van Brunt
Over “18,000 hours of independent study” in the wrong direction just moved you further from the truth.

Weather extremes are NOT increasing.

Water vapor in the troposphere is determined by the temperature of the troposphere — it is a dependent variable — a feedback to changes in troposphere average temperature.

The amount of water vapor in the atmosphere is a consequence of warming rather than a driving force,

The measurements of global average atmospheric water vapor percentage is currently impossible — that’s why scientists guess an average of 2.0% to 3.0%.

• There are some compensating effects that breakdown the positive association between atmospheric water vapor and temperature. e.g., convective aggregation leads to more efficient precip processes with warming, and net drying of the atmosphere. This phenomenon is especially effective in the tropics.

• “a feedback to changes in troposphere average temperature.”

The word “feedback” means it both acts upon and is acted on.

• William Van Brunt

Yes, and the Sun orbits our Earth.

54. Ireneusz Palmowski

Is CO2 well mixed in the atmosphere and in what layers? Does CO2 near the tropopause radiate into space or to the surface?
https://earth.nullschool.net/#current/chem/surface/level/overlay=co2sc/equirectangular
https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_TEMP_MEAN_ALL_EQ_2022.png

55. Ireneusz Palmowski

I’m afraid that soon waves of cold air will start coming down from the north.
https://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/gif_files/time_pres_HGT_ANOM_ALL_NH_2023.png

56. thecliffclavenoffinance

Climate science starts with the claim that humans have added a lot of CO2 to the atmosphere since 1850. I estimate 99.9% of scientists would agree.

That agreement includes the most famous “skeptic scientists” such as Richard Lindzen, Willam Happer, Roy Spencer and I had previously thought Judith Curry too. All Ph.D.’s. But the credentials do not matter unless their writing, speaking and editing of their websites, if they manage one, makes sense.

That means this author rejects the 99.9% consensus of climate scientists living on our planet … essentially completely rejecting all climate science, similar to the false claims of a few crackpot scientists, led by Ed Berry.

In 25 years of climate science reading, I have never seen a reader (Mr. Engelbeen) whose comments so effectively refuted an article by an author who has impressive credentials, but no common sense.

Humans added a lot of CO2 to the atmosphere. CO2 is a greenhouse gas. The arguments then begin over the effect of more CO2, and sometimes continue over whether more CO2 in the atmosphere is good news or bad news.

The author here embarrasses himself by claiming humans did not add a lot of CO2 to the atmosphere. The web owner embarrasses herself by publishing this article.

What we learned here is that credentials and Ph.D. degrees do not guarantee common sense, BUT junk science articles like this one do lead to a lot of comments and page views.

Richard Greene
Bingham Farms, Michigan

… where we celebrate global warming,
and our plants love more CO2 in the atmosphere. We don’t need Ph.D. scientists or climate computer games to tell us what to believe about the climate that we live in.

https://honestclimatescience.blogspot.com/

• ” I estimate 99.9% of scientists would agree.”

Science is not about authority or consensus.

“Why 100? If I were wrong, one would have been enough. [In response to the book “Hundred Authors Against Einstein”]”

• Agnostic

You have misunderstood the premise of the paper. The author makes no such claim, and nor does Dr Curry.

The premise about causality. Since temperature leads CO2 changes on all time scales then the causality between global warming and CO2 as it typically understood is wrong. This actually isn’t new, there are plenty of papers that show this, but this is a new and more robust way, using IPCC approved data sets.

That means that CO2 should be treated as a feedback not a forcing. For some context, global temps were around what they are today during the medieval warm period, and CO2 levels according to multiple high resolution proxy reconstructions were as much as 380-390ppm. Ice cores do not show these excursions for a number of reasons but primarily because their resolution is on millennial scales and not decadal.

Humans ARE a net source of CO2, but the carbon cycle is extremely complex. The biosphere is both source and sink and these are not always in balance. Processes that release carbon are more temperature dependent than processes that fix it, so the biosphere will suck more CO2 out of the air during cooler periods, regardless of where it came from. During warmer periods, bacteria and fungus break down biota to release CO2, CH4, and H2O faster than the biosphere can suck it out of the air. If there is more CO2 available, then the transient biosphere can expand to a larger sizer and faster, so the relationship is non-linear.

• thecliffclavenoffinance

CO2 is a feedback when changes in ocean temperature, from any cause, change the ocean / atmosphere CO2 ratio as explained many times by Mr. Engelbeen.

CO2 is a forcing when humans burn hydrocarbon fuels and add a lot of CO2 to the atmosphere. Also explained by Mr Engelbeen multiple times.

These are two different processes that happen at the same time.

The rise of ocean temperatures since 1850 added a small amount of CO2 to the atmosphere. If humans had not added more CO2 to the atmosphere since 1850, plants would have absorbed all of the small CO2 increase from the small amount of ocean warming.

So why did the atmospheric CO2 increase by 140ppm since 1850?

Simple common sense: Because humans added +200 to +250ppm of CO2 to the atmosphere. There is no other source of the added CO2. And at least 99.9% of scientists have agreed with that claim for over 50 years.

The estimated 0.1% who disagree are claiming 100% of consensus science is completely wrong, and they are right. Not 90% wrong. Not 99% wrong. But 100% wrong. Does anyone with common sense really believe the most basic claim of climate science — humans added a lot of CO2 to the atmosphere in the past two centuries – is 100% wrong?

There appears to be one author here who does, one blog owner who does by supporting that author, and several commenters too.

That basic climate science denial is why conservatives will lose the worthwhile battle to refute predictions of CAGW.

When the conservative argument starts with ‘humans did not cause the large CO2 increase since 1850’, we conservatives automatically lose the debate. Impressive credentials do not predict common sense.

Just where is that +200 to +250ppm of human CO2 emissions hiding if not in the atmosphere?

And how could a one degree C. warming of the oceans possibly cause atmospheric CO2 to increase +140ppm?

Temperature leads CO2 in the ice core era before manmadeCO2 emissions existed.

Manmade CO2 emissions lead temperature in the era of burning hydrocarbon fuels.

Science denial is a mental disease.

• Agnostic

“So why did the atmospheric CO2 increase by 140ppm since 1850?”

Because the earth warmed.

That warming started LONG before human emissions could be responsible for it.

(Incidentally – I am not conservative. I am left-leaning in my politics, but it has no bearing on the logic, reason and evidence presented here).

The issue here is causality. You cannot claim causality, that CO2 CAUSED the earth to warm, if the warming started BEFORE the rise in CO2.

THAT is simple common sense.

Excepting ENSO, the oceans are not the largest part of the carbon cycle, the land is, especially the Northern Hemisphere.

” There is no other source of the added CO2.”

Yes there is.

The source is the Carbon that has been trapped by processes that fix it over the eons. This in fact is how we have fossil fuels to burn!!

The residence time carbon in soils varies greatly between environments. It can be from a few years to 250 years. There is transient release of CO2, say from deciduous foliage, and there is longer term release of CO2 from larger organisms such as dead trees, or most importantly the soil. The warmer (and also to an extent the wetter) conditions are the FASTER the release of CO2.

Are you saying that processes that cause organic matter to decay are in EXACT balance with processes that fix it (photosynthesis)?

What do you make of the high variability of CO2 from other proxies such as stomata and foraminifera? Given that ice cores are unsuitable for showing resolution of CO2 changes of less than 800 years, these show that the biosphere is able to release and trap CO2 of the same order of magnitude as we are experiencing today. What do you make of that? Where do you think the CO2 came from in those times?

You can look for yourself – this paper is not the only one making this point. It’s long bothered me why this is not discussed. How can CO2 be driving temperature change if temperature change came first?

This is not to say that CO2 does not have warming effect – of course it does, but it should be treated as a feedback NOT a forcing. Human emissions are just a fraction of the sources for CO2, and the biosphere is indifferent to where the CO2 came from.

• David Appell

Agnostic wrote:
The premise about causality. Since temperature leads CO2 changes on all time scales then the causality between global warming and CO2 as it typically understood is wrong.

Again, wrong.

Humans are flooding the atmosphere with CO2. Independently of the temperature.

How does temperature lead CO2 in that case?

• Agnostic

No, not wrong. Specifically what did I say was wrong? There is plenty of evidence for this if you are willing to look.

Humans are not “flooding” the atmosphere with CO2. That is just subjective nonsense. We contribute 4-5% of all sources. Sinks of CO2 expand and contract depending partly on temperature and partly on the availability of CO2. This is the reason for past variation of CO2 we see in the proxy record.

“How does temperature lead CO2 in that case?”

Because it does.

Warming began from about from the late 18th, long before human emissions were sufficiently large enough to have an impact atmospheric CO2 or temperatures. CO2 only began to rise significantly from mid-20th C, long after temperature had started to increase.

It really is as simple as that – you can’t claim CO2 CAUSED the warming if the warming started first. You can claim that the warming was enhanced by the extra CO2. That’s a FEEDBACK not a FORCING.

And you see that on ALL timescales where we have adequate data. In ice cores for timescales of millennia, and stomata for timescales of decades/centuries.

57. David Andrews

Since Ferdinand and others have clearly described the errors in this paper, the comments that follow may amount to duplication and “beating a dead horse”. But perhaps reinforcing and rephrasing some of the contradictions the paper contains may help Demetris and others if they do not yet understand.

1. I have previously cited Ballantyne, et al., 2012: Increase in observed net carbon dioxide uptake by land and oceans during the past 50 years, Nature, vol 488 pp 70-72. doi:10.1038/nature11299. They focus on “net global uptake”, the difference between human emissions and atmospheric CO2 rise or, by carbon conservation, the quantity by which land/sea reservoirs of mobile carbon have increased. Ballantyne documents the increase in this quantity between 1960 and 2010. Their numbers for that entire period are:
Human emissions 350 + 29 PgC (petagrams of carbon)
Atmospheric accumulation 158 + 2 PgC
Net global uptake 192 + 29 PgC

Note that carbon, not CO2, is being tracked, as it is the conserved quantity. Note that arriving at net global uptake by using carbon conservation this way is much more accurate than taking the difference between uncertain estimates of natural absorptions and natural emissions. Our knowledge of net global uptake over this period is good to 15%. (If anyone wishes to dispute that, we can discuss the methods of Ballantyne et al., but I do not think that should be necessary.) Attempts to deny human responsibility for atmospheric CO2 rise with vague statements about “uncertainty in the carbon budget” without doubt misinform. That is not a political statement as Demetris suggests. It is a fact. I have to note that rebutting an argument by calling it “political” is a sign of weakness.

2. The atmosphere (see Mauna Loa), vegetation (see testimonials to the greening effects of CO2), and the oceans (see ocean acidification) all contain more carbon now than they did in 1960. Oil and gas reserves and coal seams within the earth contain less. But we are asked by this paper to conclude that removing that fossil carbon from the earth and burning it is not the reason other carbon reservoirs have increased. Nonsense.

3. I agree with the Demitris‘ approach of treating the whole system together. Some (e.g. Harde and Salby) have gotten in trouble by analyzing “human carbon” and “natural carbon” separately. I also agree that “causality” in complex systems is tricky. Ballantyne et al. see an approximately linear increase, decade by decade, in net global uptake. But they also see fluctuations superposed on that trend, perhaps attributable to volcanic activity. In other words, atmospheric CO2 levels do depend somewhat on natural processes as well as human activity, making it difficult to call 100% of the industrial age increase anthropogenic (though I have done that elsewhere myself). Still, there can be no doubt that the dominant cause of long-term atmospheric CO2 rise in our era is fossil fuel burning.

4. Sadly, however strong a case is made against this paper, from experience I have little hope that it will be retracted. That is the divided world we live in.

• “Our knowledge of net global uptake over this period is good to 15%.”

How do you justify making such an assertion when no one has mentioned what is happening in the Arctic, the NASA observation of ‘greening,’ and the utterly unknown situation of submarine volcanic emissions?

How do you propose to identify and dismiss spurious correlations?

• Clyde as said elsewhere, we do not need any natural flow for the carbon balance: that is exactly known from human emissions minus increase in the atmosphere: that is exactly what nature did in the same year: always more sink than source in the past 60 years…

• David, one of the problems with Demetris’approach is that he doesn;t include the whole system: he is looking only at the input side and forgot to account for the output side…

Even if one looks at the whole picture, it is clear that his “temperature cause” is wrong:

Take all human emissions away at once, and suddenly the whole system is a net sink of (first year) 5.1 GtC, next year a little less etc. back in the direction of the 295 ppmv equilibrium (if that is ever reached is a different discussion…).

Temperature has little to do with the increase as that is only 16 ppmv/K

• Agnostic

“Take all human emissions away at once, and suddenly the whole system is a net sink”

I think this has been addressed elsewhere, but it’s worth putting a comment here (since it really is sand in my pants).

It does NOT follow that taking away human contributions would make the “whole system a net sink”. All that it would mean is that the system would expand slightly slower. If temperature is driving warming, then the system increases in size to adapt to available CO2, and were we to have not emitted any CO2, atmospheric concentrations would have still increased, just as they did in pre-industrial times on time scales of centuries and millennia.

58. We are considering the vast CO2 natural reservoirs (oceans and land), we are considering their vast CO2 content, along with the tiny ~400 ppm CO2 content in the actually very thin atmosphere.

At current average global temperature it is the ~400 ppm CO2 content which is in equilibrium interaction with the CO2 natural reservoirs. Or, to say diferently, at current average global temperature, the natural CO2 reservoirs with their mighty CO2 content “support” the ~400 ppm CO2 equilibrium content in earth’s atmosphere.

What we observe is that there is a rise in earth’s global temperature.
Also, it is measured, that there is an annual ~2 ppm CO2 content rise in earth’s atmosphere.
And, it is estimated, ~4 ppm CO2 content (as added amounts of CO2 from the fossil fuels burning) is annually added to the earth’s atmosphere.

So, we have, from the fossil fuels burning, annually added
~4 ppm CO2, but the annual rise of CO2 is ~2 ppm.

It is the 400 ppm which are actually being “supported” by natural reservoirs.
The average global temperature rise is the cause of that
~2 ppm CO2 rise in earth’s atmosphere, and not the fossil fuels burning.

https://www.cristos-vournas.com

• Christos,

For the current ocean surface temperature, the equilibrium CO2 level in the atmosphere would be 295 ppmv per Henry’s law. Not 400 ppmv. Quantities play no role at all, only CO2 pressure (differences) at the ocean surface and in the atmosphere.

Shake a 0.5, 1 or 1.5 liter bottle of Coke from the same batch and you will find about the same CO2 pressure under the screw cap…

• Ferdinant,

“Clyde, i may have missed your question of “overlooked sources”, but in fact that is completely irrelevant: we don’t need to know anything of any natural source or sink to know the overall performance of all sources and sinks together.

We know human emissions: 5 ppmv +/- 0.25 ppmv per year
We know the increase in the atmosphere: 2.4 +/- 0.2 ppmv
The performance of all natural in/out fluxes then is -2.6 +/- 0.45 ppmv per year. The margin error is probable smaller, but forgot how to calculate a multiple error propagation…”

Your’s above comment is a perfect description of how exactly about the CO2 performance out there the things are…

You also said
“For the current ocean surface temperature, the equilibrium CO2 level in the atmosphere would be 295 ppmv per Henry’s law. Not 400 ppmv. Quantities play no role at all, only CO2 pressure (differences) at the ocean surface and in the atmosphere.”

Well, of course the CO2 partial pressure in the atmosphere is one of the factors, another one is the temperature. Those are some of the major contributing factors in regulating the equilibrium CO2 level in the atmosphere…

The GLOBAL equilibrium level in the atmosphere is 400 ppmv.
On the other hand, Henry’s law has to do with the gases/liquid equilibrium in a closed volume.

Atmospheric CO2 equilibrium with oceanic waters has similar dependencies as Henry’s law, dependencies on CO2 partial pressure in the atmosphere, and on the temperature of the water and the temperature of the atmosphere – to mention few of the major factors.
Henry’s law cannot be applied as it is in the case of GLOBAL atmospheric CO2 equilibrium with oceanic waters.

In Henry’s law estimation of “the equilibrium CO2 level in the atmosphere would be 295 ppmv per Henry’s law.” there is only one temperature plays role.

In the case of atmospheric CO2 equilibrium with oceanic waters we do not have a fixed average temperature, what actually we are dealing with is a much more complex phenomenon there.

That is why I insist “The GLOBAL equilibrium level in the atmosphere is 400 ppmv. ”

https://www.cristos-vournas.com

• Christos, the equilibrium CO2 level in the atmosphere for the atmosphere – ocean surface equilibrium over the past 800,000 years changed with about 16 ppmv/K over multi-millennia. That is all. 13 ppmv since the LIA, not 135 ppmv.

For the current, area weighted, ocean surface temperature, the pCO2 of the oceans would be 295 μatm (~295 ppmv).
The temperature of the atmosphere plays no role, the CO2 pressure (~415 μatm) is what counts: a difference of ~120 μatm. That is what pushes more CO2 into the oceans than they release.

That is a dynamic equilibrium: some 40 GtC/yr is released by equatorial upwelling waters, some 40 GtC/yr is taken away by sinking waters near the poles. With currently ~2 GtC/yr more uptake than release, caused by the extra CO2 pressure in the atmosphere.
Similarly for vegetation, but the pCO2 in plant leaves is difficult to measure, but the result is known: ~2.5 GtC/year net uptake.

The temperature influence on the pCO2 of seawater is exactly known by the formula of Takahashi, based on hundred thousands of seawater samples:
∂ln pCO2/∂T=0.0423/K
See: http://www.sciencedirect.com/science/article/pii/S0967064502000036

There are enormous differences in sea surface pCO2: between 750 μatm near the equator to 150 μatm near the poles. That gives the release and uptake of CO2 in seawater. At the poles that CO2 sinks with the THC waters into the deep to return ~1000 years later near the equator.

There is no difference in a static pCO2 for a uniform temperature over all oceans or for dynamic real ocean with the same average temperature. A sudden increase of 1 K over the full surface will give the same ~16 ppmv increase in the atmosphere:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/upwelling_temp.jpg

• Ferdinand,
“There are enormous differences in sea surface pCO2: between 750 μatm near the equator to 150 μatm near the poles. That gives the release and uptake of CO2 in seawater. At the poles that CO2 sinks with the THC waters into the deep to return ~1000 years later near the equator.”

Good.

“There is no difference in a static pCO2 for a uniform temperature over all oceans or for dynamic real ocean with the same average temperature.”

Ferdinant, are you aplying Henry’s law to “for a uniform temperature over all oceans or for dynamic real ocean with the same average temperature.” ?

https://www.cristos-vournas.com

• Ferdinand, from the good article you provided :
http://www.sciencedirect.com/science/article/pii/S0967064502000036

Here it is what I consider very important:

“Seasonal variation of pCO2 in surface waters
On a global scale, the temperature effect on surface-water pCO2 is similar in magnitude but opposite in direction to the biological effect, in which changes of the total CO2 concentration is the dominant factor. The pCO2 in surface ocean waters doubles for every 16°C temperature increase (∂ln pCO2/∂T=0.0423°C−1, Takahashi et al., 1993). For a parcel of seawater with constant chemical composition, its pCO2 would be increased by a factor of 4 when it is warmed from polar water temperatures of…”

“The pCO2 in surface ocean waters doubles for every 16°C temperature increase (∂ln pCO2/∂T=0.0423°C−1, Takahashi et al., 1993).”

Below I reference an important paper from 1974. Maybe it is 50 years old, but it never losses its actuallity!

https://refp.cohlife.org/_carbon_dioxide/Carbon%20dioxide%20in%20water%20and%20seawater_%20the%20solubility%20of%20a%20non-ideal%20gas%20(1974)%20%5B10.1016_0304-4203(74)90015-2%5D%20-%20libgen.li.pdf

https://refp.cohlife.org/_carbon_dioxide/Carbon%20dioxide%20in%20water%20and%20seawater_%20the%20solubility%20of%20a%20non-ideal%20gas%20(1974)%20%5B10.1016_0304-4203(74)90015-2%5D%20-%20libgen.li.pdf

• Christos Vournas,

“Ferdinand, are you aplying Henry’s law to “for a uniform temperature over all oceans or for dynamic real ocean with the same average temperature.” ?”

A am applying that for the real oceans, with an enormous difference between pCO2 of the oceans near the poles and at the equator.

If the oceans increase 1°C in temperature everywhere over all oceans, then the local temperatures near the equator would increase from 30°C to 31°C and the local pCO2 of seawater will increase from 750 μatm to app. 766 μatm (by the formula of Takahashi). That makes that the pressure difference of CO2 between ocean surface and atmosphere near the equator will increase from 750 – 415 = 335 μatm to 766 – 415 = 351 μatm.
Because the uptake / release is directly proportional to the pressure difference, that means that the original ~40 GtC/year emissions from the oceans increased to about 42 GtC/year.
The opposite happens near the poles, where the uptake by a warmer ocean surface also reduces with some 4%, initially giving an extra 4 GtC/year out of the ocean imbalance.

The following increase of CO2 in the atmosphere then has the opposite effect: the increasing pCO2 in the atmosphere reduces the pCO2 difference between ocean surface and atmosphere until a new equilibrium is established at about 16 ppmv higher in the atmosphere, exactly the same increase as if the whole ocean surface had the same temperature as one big static sample.

Here in graph form for a sudden increase of 1°C in ocean surface temperatures:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/upwelling_temp.jpg

• Ferdinand,

“If the oceans increase 1°C in temperature everywhere over all oceans,”

For the oceans to increase 1°C in temperature everywhere over all oceans is impossible.

Ferdinand, you are aplying Henry’s law to “for a uniform temperature over all oceans or for dynamic real ocean with the same average temperature.”
It is impossible.

https://www.cristos-vournas.com

59. Ireneusz Palmowski

Look at the seasonal variation in CO2 in both hemispheres near the surface. Especially pay attention to vegetation in the oceans. Do you really think the magnitude of CO2 added by man is greater than the natural variability? Recall what the oxygen content of the atmosphere was before cyanobacteria took over the oceans?
https://earth.nullschool.net/#2023/08/30/0600Z/chem/surface/level/overlay=co2sc/equirectangular

• Human addition indeed is near always larger than the natural variability:
+2.5 ppmv/year emissions
+/- 1 ppmv/year natural variability
+1.5 ppmv for an El Niño years
-1.5 ppmv for the 1991 Pinatubo.

What happens within a year over the seasons is of no interest for the mass balance over a full year, neither what happened in ancient times…

60. One way to think about this might be to ask yourself what would happen if global climate cooled. As long as the rate of addition of man-made CO2 was constant, I would expect the oceans to absorb a greater proportion of the total CO2 in the atmosphere. The surface layers of the ocean mix with atmosphere pretty well, so the effect might be seen in a few years.

• So in this case I would expect the atmospheric concentration of CO2 to go down. More would be absorbed than before the temperature decrease.

• The increase in the atmosphere with a constant CO2 addition would go down a little (16 ppmv/K), but still increase until net sinks and human addition are equal.

With a sink rate of 2% of the pCO2 difference and a constant 5 ppmv/year addition, the sinks will reach 5 ppmv/year at 250 ppmv over the current 295 ppmv equilibrium. Thus at 545 ppmv in the atmosphere…

• Engelbeen – so if a colder global mean temp would cause a decrease in CO2, then a warming mean would shift the equilibrium between atmosphere and ocean towards the ocean emitting more CO2. Therefore, not all the increase is from humans.

• Jim2, I do agree, but the increase caused by temperature is only 13 ppmv since the depth of the LIA, around 1600.

All the rest of the app. 135 ppmv increase is caused bu human emissions, so 90% human, 10% natural. Not reverse (according to Salby, Harde, Berry,…)

• jim2,

Agreed: only 10% (13 ppmv) is from warming ocean surfaces, 90% from human emissions…

61. Below, I am making public my replies to a personal exchange with Ferdinand:

I think I have rebutted all the different critiques ON MY PAPERS. I am not going to reply to critiques on any other issues related to the issue of climate. Please make your critiques SPECIFIC, by quoting phrases in my papers that you think are incorrect. And before it, please read the papers.

For example you say:

> And that would be the cause of the CO2 increase in the atmosphere?

If you read the paper you will see that we write (p. 17): *What is the cause of the modern increase in temperature? Apparently, this question is much more difficult to reply to, as we can no longer attribute everything to any single agent. We do not claim to have the answer to this question, whose study is far beyond the article’s scope. Neither do we believe that mainstream climatic theory, which is focused upon human CO2 emissions as the main cause and regards everything else as feedback of the single main cause, can explain what happened on Earth for 4.5 billion years of changing climate.*

You say:

> What you forgot to mention is that the additional natural sinks also increased, even more than the additional natural sources (amounts not given in your graph, but visually likely).

*So, why you say we forgot it, since you recognize that it is in our graph?

You say

> Nothing of magic, but CO2 is lagging temperature on short (2-3 years) time scales with a CO2/T ratio of 3-4 ppmv/K
> On very large time scales (centuries to multi-millennia) CO2 is lagging T with a ratio of 16 ppmv/K
> Over the recent 170 years the ratio suddenly increased to 110-120 ppmv/K which must be magic, as it is physically impossible that temperature suddenly has a much larger influence on CO2 levels than in shorter ánd longer periods.
> While there is an elephant in the room, human emissions that released twice as much CO2 as measured in the atmosphere…

We have proposed a necessary condition for causality, which is time precedence of the cause over the effect. I hope you accept that necessary condition, am I wrong? We make our inference based on this necessary condition. Your numbers make no reference of time succession. When you find a way to test whether the direction in time is reversed, that will be great. But for now, all this looks to me an unproven conjecture. I hope you can excuse me that, being a Greek, I have to stick to Aristotelian logic.

You also say:

> While there is an elephant in the room, human emissions that released twice as much CO2 as measured in the atmosphere…

If this is the elephant, what is (copying from our paper, p. 25), *a total global increase in the respiration rate of ΔR = 31.6 Gt C/year. This rate, which is a result of natural processes, is 3.4 times greater than the CO2 emission by fossil fuel combustion (9.4 Gt C /year including cement production)*.

• Demetris,

On my question what is the cause of the CO2 increase, you answer with what the cause is of the temperature increase, which is not an answer to my question…

Nevertheless:
The answer indeed is in the IPCC graph:
Between 1750 and now, the natural CYCLE (not only the natural releases, also the natural sinks) increased with over 30 GtC/year.
What you forgot is that a balance has two sides: earnings and expenses. In this case, the expenses increased with 5.1 GtC/year MORE than the earnings.

That respiration did grow with 31.6 GtC/year is absolutely irrelevant for the carbon balance: only the difference between the sum of all ins and outs is important.

In detail: both the oceans and vegetation are proven, increasing (!) sinks for CO2, thus these two can’t be cause of the increase in the atmosphere.
It really is that simple…

All you have proven is that the 2-3 year CO2 variability in sink (not source!) rate around the net sinks trend (of oceans and vegetation) is caused by temperature variability. Nobody disputes that.

Because the trend of the net sinks in nature is negative with a positive temperature trend, it simply is impossible that temperature is leading the net sink rate. The increasing pressure difference between pCO2 in the atmosphere and the oceans is what increases the net sink rate.
Again the relevant graph:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8.jpg

At last, equation (9) is just curve fitting and has no physical base.

In the same way, one can show that human emissions are for 99% responsible for the increase, just by comparing the trends:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_cur.jpg
Already since 1900 (including ice core CO2 measurements). Need some update for the last decade, but that will not change the curve.

That this is just coincidence is thanks to the fact that human emissions increased slightly quadratic over time (linear in the derivatives)…

• Ferdinand Engelbeen.

You wrote: “If humans are not to blame, what is the “other” source (both oceans and vegetation are increasing net sinks) and where resides all that human CO2?”

Don’t you think that subject is beyond the scope of the paper? The chicken and egg problem is the first question that needs to be answered. But if you do want to know what might be driving temperature, I suggest you look here.

https://github.com/bobf34/GlobalWarming/blob/main/hybridmodel.md

You also wrote: “Because the trend of the net sinks in nature is negative with a positive temperature trend, it simply is impossible that temperature is leading the net sink rate. The increasing pressure difference between pCO2 in the atmosphere and the oceans is what increases the net sink rate.”

I suggest you consider my original response to Demetris above. This analysis simply looks at two signals, which could represent anything and asks not only how they are related, but also if they’re related. The fact that the both signals trend up doesn’t prove that they’re related. What I’ve shown is that the co2 signal is related to the temperature signal, and that it lags the temperature signal by six months. Forget sources and sinks. This is a basic fact for these two signals.

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993850

I know that everyone might not understand my results, so allow me to expand on them here.

First, look at the spectrum of the Mauna Loa CO2 signal.

https://localartist.org/media/MaunaLoaCO2.png

Ignore the largest term near 0 year^-1. That’s the energy of the overall trend, from which it is impossible to tell what leads and what lags. Also ignore the 1 year and 6 month (2 year^-1) oscillations. Those season tones are also not important, and won’t interfere with my results in a frequency-domain analysis. What’s important is the stuff that looks like noise that falls off with frequency. It’s not noise, it’s detail.

Here’s the spectrum again this time I’ve added the spectrum of global temperature. What I want you to notice is that the temperature spectrum looks very similar to the co2 spectrum between 0 and 1 Year^-1. OK, but are they the same?

https://localartist.org/media/co2tempspec.png

The answer is that while they aren’t identical, they do share a common signal. I can see that in the the coherence analysis.

https://localartist.org/media/CO2_Temp_FRF.png

The coherence and spectrum analysis shown here break the signal into smaller chunks and averages the results together. The reason for doing this is that if two signals are uncorrelated, they wont have the same phases over time even if they have the same spectral shape in amplitude. In the frequency response, any uncorrelated signal such as noise goes away with averaging. In the coherence plot, where the signals have something in common the coherence will be remain high. For frequencies where the signals have little commonality, the coherence will decrease with an increase in the number of averages. That’s why I’m showing three results, so we can observe the trends as the number of averages is increased. Unfortunately, with a finite amount of data, I have to use shorter chunks, which results in less frequency resolution.

You might wonder why the delay in the phase response is shown as a sloped line. The reason for this is that a fixed delay represents a different amount of sinusoidal phase depending on frequency. For a 1-year cycle, a six month delay is 180 degrees. For a two-year cycle, the same delay is only 90 degrees.

The bottom line is that the c02 signal lags the temperature signal by six months, and that appears to be true for any interval you might want to consider longer than 1 year, or at least for frequencies lower than 0.75 Year^-1, which is where the coherence starts to drop.

I’ve plotted the Hamming window shape in the coherence plot. That’s to help understand the extent of the large low-frequency spike and sidelobes as frequency resolution changes

For completeness, I’ve recreated the graph, this time using the ln(CO2) and also using a Flattop window, which has very low side lobes. This eliminates any possibility that the analysis was tainted by window leakage.

I’ve also performed the analysis using Northern and Southern temperature data. The 6-month delay result doesn’t change.

• Agnostic

“In detail: both the oceans and vegetation are proven, increasing (!) sinks for CO2, thus these two can’t be cause of the increase in the atmosphere.
It really is that simple…”

And ironically, this is exactly where you are wrong. Just because they are increasing as sinks does not mean they cannot be increasing as sources. I think you are too stuck on the idea of a “budget”, it’s a linear view. It’s the “net” thing that is where the misunderstanding is.

The biosphere is indifferent to our contribution. If there is more CO2 available it will expand regardless of where it came from. Temperature increase, particularly in winter, means that more CO2 is released in biodegradation than normal. If it releases more than is fixed during the summer growing season, then atmospheric CO2 levels will increase.

During the growing season, if there is more CO2 available, then the biosphere can grow more vigorously and expand. Some of this is semi-permanently fixed, and some will only fix during the growing season to be available to be released as CO2 during the next winter.

If the humans made no contribution, the atmospheric CO2 would still go up, though perhaps not by as much, just as it did in other warm periods during the holocene. This “budget” idea is what is causing the confusion.

• Robert,

I do vaguely remember what frequency analyses does, but never used it, as in my job the focus was on mechanical/chemical problems.

The question to you that I posed somewhere else (lost in all the replies…) is what happens if you have two independent variables: one with a huge slope and zero variability and the other with zero slope and a lot of variability. The dependent variability showing a huge slope and a lot of variability…

That is what happens with CO2 in the atmosphere today.

My impression is that with frequency analyses you will find that there only is a correlation between temperature and CO2 variability and nothing from human emissions for the simple reason that there is hardly any variability in human emissions, only a slope.

Have a look at the real life trends and variability (temperature enhanced with a factor 3.5 to have a similar amplitude as CO2 variability) in the derivatives:

Keep in mind that the slope of human emissions is twice the slope of the CO2 increase in the atmosphere…

The answer to the question of what happens to human CO2 and what is the natural source of the CO2 increase as result of the very small T increase over time therefore is quite essential.

• Ferdinand

“The question to you that I posed somewhere else (lost in all the replies…) is what happens if you have two independent variables: one with a huge slope and zero variability and the other with zero slope and a lot of variability. The dependent variability showing a huge slope and a lot of variability…”

Allow me to apologize, I didn’t see your question. There is a lot of traffic.

First, here are some new plots with markers and a bit more overlap in the averaging. The ln() function is not used for these.

The quick answer to your question is that the trend is captured in the low-frequency peak, and everything to the right of the peak is the non-trend energy. As computed, averaging will reduce the contributions of any signal that is not correlated to the temperature signal — except for the trend. The frequency of the trend is too low.

Here’s the long answer, if anyone’s interested.

The FFT used to compute spectrums maps the time series onto an orthogonal set of sinusoids. If I have a 10-year time record then frequencies of the sinusoids would be 0, 1/10, 2/10, 3/10 … yr^-1

For the data we’re discussing here, the upward trends is not a sinusoid, nor is it even close to being periodic within the dataset. If I didn’t use a window to force periodicity on in, then the trend would map onto a large number of frequencies giving the impression of significant frequency content where there is none. With a window, the long trend maps mostly onto the first few frequencies. That’s the large low-frequency spike in the top plots with an amplitude of almost 40dB. You can think of this as a form of detrending as all of the spectral energy to the right of that spike is faster than the trend.

Now, as to identifying what’s dependent and what’s not, I’ll start by saying that I can’t do that for the overall trend with this analysis, the frequency is too low for cancellation from randomized phases, but I can provide some detail about what’s going on elsewhere.

To keep my discussion as carbon-free as possible, I’m going to talk about a generic system which I’ll describe in the frequency domain as Y(f)=H(f)X(f)+N(f), or more simply Y=HX+N.

For the plots above I chose x(t) as temperature and y(t) as CO2. The top and middle plots are estimates of H. You could describe N as non-temperature related CO2, but it would also include random measurement noise. If n(t) and x(t) are uncorrelated then we can also say that the expected value of NX* is zero where * denotes the complex conjugate operator.

We start by computing the cross spectrum as YX* = (HX+N)X* = HXX*+NX* . If we compute YX* over different time intervals and average the results together, the NX* term in the cross spectrum tends to zero as the number of averages increase.

The H1 estimator of H is average(Gyx)/average(Gxx) and the coherence is computed as |avg(Gyx)|^2/(avg(Gyy)avg(Gxx)). The value of this coherence estimator is that the numerator tends to zero if y(t) and x(t) are uncorrelated, or be low if there is very little x in y. Coherence helps us judge the quality of the H1 estimator.

Looking at any of the three graphics you’ll see that the magnitude of the trend term doesn’t vary. Unfortunately, we can’t use that as evidence of anything. We could as why it’s so big, but we can make the same statement about the peak at 1 yr^-1. More on that below.

The marker at a frequency of 0.3 yr^-1 is relatively stable with averaging at about 3 ppmv/K, and the coherence, while low, is not unreasonably low. This seems to hold out to about 0.5 yr^-1. These frequencies are also where we observe a 6-month lag in CO2.

Things become a bit more interesting for the annual cycle. The amplitude is dropping rapidly with averaging. Without more data we can only guess at where it would settle out. You can see that the coherence is quite a bit lower for the annual cycle than it is for the “noise” below 0.5 yr^-1. There are two ways to interpret this. First there may be uncorrelated energy in N at ~1 yr^-1. Second, H(f) may actually be H(f,t) which randomized the phase of X, e.g. some form of dynamic feedback.

If you look carefully at the NH and SH plots. The coherence is higher at 1 yr^-1 in the NH result. Also, if you compare the drop in magnitude between the left and right plots, you’ll find about an 8 dB drop for the NH, and a 14 dB plot for the SH.

• David Appell

Agnostic wrote:
If the humans made no contribution, the atmospheric CO2 would still go up, though perhaps not by as much, just as it did in other warm periods during the holocene.

Why?

• Agnostic

David Appell: “Why?”

I have explained this numerous times, but to reiterate:

Because sources and sinks are coupled interdependent variable reservoirs. One reservoir (sinks) is less temperature dependent than the other (sources), so there is always an imbalance. It’s well known that sinks are expanding and they expanding faster than our contribution – about twice as fast. They are expanding largely because there is more CO2 available, the so called “fertilisation effect”.

The reason is, during warm periods, more CO2 is produced by temperature dependent processes (biodegradation) than is fixed by photosynthetic processes (trees, algae in the oceans etc), thus atmospheric CO2 increases. But when there is more CO2 available, the reservoir that fixes carbon GROWS – it expands – offsetting the increase in CO2 induced by the warmth from biodegradation.

We don’t have to guess at that, we can see it in the paleo record on all timescales. There is plenty of evidence showing fluctuations of 100ppm or more on timescales of less than a century.

Furthermore, there are annual fluctuations of natural sources that are LARGER than the total annual emissions from humans. That means that annual changes to sinks of CO2 are of an order that can adjust to the amount of CO2 that humans emit, it just means the sinks remain larger than they would have been had we not emitted CO2 (about 4% larger). It’s entirely possible that levels of CO2 would have risen to current levels even if we were not emitting CO2. I suspect though, that we HAVE contributed to atmos CO2, but probably only as much as the difference between current levels and levels from prior warm periods such as the MWP…so around 25-30ppm.

62. Demetris, thank your for your research, publication and participation in this discussion. As you are Greek and also philosophical in your reflections, the dialogue above reminded of your ancestors. I was introduced to their wisdom by an American Philospher, Mortimer Adler. Here are some words from him pertaining to this search for truth.

Knowledge refers to knowing the truth, that is understanding reality independent of the person and his/her ideas. By definition, there is no such thing as “false knowledge.”

When I show you two marbles then add two more marbles and ask you how many marbles there are, the answer is not a matter of opinion. You have no freedom to assert any opinion other than the answer “four”. By the axioms of mathematics we know the true answer to this question.

A great many other issues in human society, politics and culture are matters of opinion, and each is free to hold an opinion different from others. In such cases, the right opinion is usually determined by counting noses with the majority view ruling.

Note that school children are taught right opinions. That is, they are told what their elders and betters have concluded are the right answers to many questions about life and the world. Those children do not yet possess knowledge, because as Socrates well demonstrated, you have knowledge when you have both the right opinion and also know why it is right. Only when you have consulted the evidence and done your own analysis does your opinion serve as knowledge for you, rather than submission to an authority.

Any teacher will tell you it is much easier to teach a student who is ignorant than one who is in error, because the student who is in error on a given point thinks that he knows whereas in fact he does not know. . .It is almost necessary to take the student who is in error and first correct the error before you can teach him. . .The path from ignorance to knowledge is shorter than the path from error to knowledge.

• David Andrews

Ron,
Perhaps with your wisdom, you can tell us how to reconcile the contradictions in Demetris’ argument. He agrees that more carbon from anthropogenic sources is going into the atmosphere than stays there. Good. He concedes that land/sea reservoirs are therefore net sinks of mobile carbon. Good. He understands that those of us criticizing his paper consider this the central issue, the “elephant in the room”. Good. But his response is simply to say that gross natural emissions exceed anthropogenic emissions, ignoring natural absorbtion processes which he has conceded are greater! Where does the increased carbon in the oceans, in vegetation, and in the atmosphere come from if not from the depleted fossil fuel reserves and calcum carbonate used in cement production? Demetris is being crushed by the elephant in the room! He needs your help!

• Spare us the sarcasm David. As I showed earlier in this thread, changes in CO2 lag changes in temperature on all time scales. It is simple but wrong to explain all the CO2 rise in atmosphere is from the 4% human contribution.

I understand the IPCC takes two things that are measured: monthly atomspheric CO2, and estimates of hydrocarbon emissions calculated from changes in fuel inventories based on assumptions of combustion efficiencies. So it is tempting to claim nothing else matters but those two data.

Back in the day when IPCC was interested in scientific facts, estimates of CO2 natural emissions were more realistic:

https://rclutz.files.wordpress.com/2017/05/co2-natural-emissions.png

Note that insects are estimated to produce up to 10 times what human do. And the variation in oceanic emissions is estimated to be 10 times what humans emit. Those are the elephants in this discussion whose behavior is poorly measured, but considered to be an order of magnitude greater.

• David Andrews

Ron,
Thanks for your response. I think we have an opportunity for a “teaching moment” for you, and for Demetris if he is reading. Perhaps also for Dr. Curry.

I did not know that insects may produce up to 10x the CO2 emissions of humans, but I will take your word for it. Let’s think about the carbon in those insect emissions. I am not an entomologist and don’t know if caterpillars exhale CO2, but they surely return carbon to the atmosphere if they get squashed and subsequently decay. Where had that carbon been before? Some would have come from a leaf the caterpillar chewed. The leaf would have pulled carbon out of the atmosphere during photosynthesis, maybe last spring. The atmospheric carbon could have come from many sources, including the caterpillar’s late grandfather. You can see where I am going. The insect emissions are part of the carbon CYCLE, more specifically the “fast carbon cycle”. The insects are part of this cycle, but don’t add any carbon to it. Their carbon “emissions” to the atmosphere are balanced, quite precisely in the long term, by processes like photosynthesis that have removed carbon from the atmosphere.

When you and I eat our breakfasts, exhale, etc. we are like insects: participating in the carbon cycle and not materially changing the amount of carbon in it. But you and I, with some help, do something else that insects don’t do. We dig up and burn fossil fuel carbon that had been sequestered for millions of years, adding it to the fast carbon cycle. This increases carbon in the atmosphere, oceans, and biosphere. It is inappropriate for you to dismiss the anthropogenic contribution as “only 4%”. Demetris makes the same mistake of comparing apples with oranges. New carbon fluxes into the fast carbon cycle from fossil fuel burning and cement production are not the same as carbon fluxes already there.

Your final comment about “poorly measured” natural processes suggests that you have not understood the power of computing “net global uptake”, but I will not repeat in detail my earlier comment here. Indeed total natural emissions and total natural absorptions are both poorly known, but their difference is known quite accurately.

63. look.

I watched the Fires in Maui, the fires Caused Sparks and Embers.

Now people are arguing that Embers and Sparks Cause Fires!!!!

Imagine that, causes coming before And After Effects.

bottom line you dont need statistics or data to Know

Physics tells you

A increased C02 causes a slowing of the flux out
flux out reduction cause temperature increase.

if your data and stats argue otherwise, you screwed up.

B. increased temperature causes increased C02.

as for figuring out the chicken and egg

you need a Nobel Brain. not a water brain

• Joshua

> if your data and stats argue otherwise, you screwed up.

Data and stats don’t argue. Demetris argues.

Now there’s in interesting study for direction of causality.

• The problem is that Demetris doesn’t address the legitimate questions that arise from his calculations:
If humans are not to blame, what is the “other” source (both oceans and vegetation are increasing net sinks) and where resides all that human CO2?

• Agnostic

Ferdinand writes: “If humans are not to blame, what is the “other” source (both oceans and vegetation are increasing net sinks) and where resides all that human CO2?”

The same question has to be asked to explain the high variability of CO2 atmospheric concentration prior to industrialisation. The CO2 had to come from somewhere: during the MWP it was as high as 380-390ppm before dropping to 285ppm. During the Bolling-Allerod CO2 increased to as much as 420ppm while temps were actually cooling, a break in the pattern of Temp leading CO2 which holds over all timescales.

The answer is that the biosphere is massively more complex than you are appreciating. You claim that the biosphere is net sink because our emissions are grater than the amount that atmospheric CO2 is rising, but that thinking is too simplistic. It is likely, almost certain given previous periods of warming, that atmospheric CO2 would have risen anyway, but perhaps by not as much, which is our contribution.

The biosphere is expanding because more CO2 is available and is therefore a source as well as a sink. Were we not contributing our share, it would be a net source.

• Agnostic,

As far as I know, there is no “high variability” before the industrial revolution in the CO2/T ratio: from ~10 ppmv/K between MWP and LIA, as seen in the high resolution (~20 years) Law Dome ice core and 16 ppmv/K in low resolution (560-600 years) ice cores over the past 800,000 years and up to 2 million years in sediments.
Vegetation had some role, but was not the dominant respondent over glacial/interglacial changes, as there is little change (a few tenths of per mil) in the 13C/12C ratio, which is the main difference between the response of seawater and of the biosphere on temperature changes.

If you refer to e.g. stomata data, these are “proxy’s”, not direct measurements, while ice cores are direct measurements of ancient air, be it from a mix of years, depending of the snow accumulation rate.
Stomata data have some problems: they reflect local CO2 in air, not “background”, as they are influenced by local changes like changes in landscape, also in the main wind direction. Even the main wind direction may have changed in the past in certain periods (MWP vs. LIA).

Thus what is your source of these high CO2 levels?

• Agnostic

Ferdinand:

“As far as I know, there is no “high variability” before the industrial revolution in the CO2/T ratio”

And I guess that’s the crux of the problem – you do not know.

Stomata and foraminifera proxies calibrated to air flasks show much much greater variability than ice core data. The problem with ice cores is diffusion, so they do not become fixed until they pass the firn layer which takes decades. As such they are not useful for resolution of <800 years.

Here are some papers showing CO2 levels comparable to today:

"CO2 rises somewhat (230-250 ppm) immediatelyafterthe GI-1/GS-1 (Allerød/Younger Dryas) boundary before decreasingabruptly again to values around 200 ppm"

"ﬁrst to minimum values of 175-190 ppm at theGS-1/Holocene boundary (3.24 depth), before rising sharply to280-300 ppm, and staying at that level through the next 95years….This again indicates a ca 100 ppm rise in CO2 in <100 years"

"which marks a shift from a warmer to a colder climate state, CO2 increases markedly before the boundary and peaks at ca 400-425 ppm before it decreases again and then stabilizes after the boundary into a pattern of lower-amplitude
ﬂuctuations withaverage values of 230-250 ppm during GS-1"

That whole period is absolutely fascinating.

Wagner et al 2004:

"Both records provide independent evidence for rapid CO2 fluctuations on time-scales varying from decades to centuries. While the estimated amplitudes of 20 to 30ppmv in the Q.roburrecordare in good agreement with the fluctuations documented for the Preboreal oscillation and the 8.2kyr event, the maximum change up to 60ppmv estimated in the T. heterophylla record exceeds the other records."

There are dozens like this. Where did all that CO2 come from?

• Agnostic,

Please… Stomata data are LOCAL data from trees that grow on soils which respire hundreds of a ppmv each night and remove the same and more during the day.

Local data in modern stations in a rural (!) surrounding, not even in a forest, may show hundreds of a ppmv difference between day and night under inversion. Here an example of Giessen/Germany, where CO2 samples are taken every half hour, compared to the raw (!) data of Barrow, Mauna Lao and South Pole, including all outliers:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/giessen_background.jpg

So why you believe that stomata data are accurate CO2 proxies for global CO2 levels?
They show the local variability of what happens in the main wind direction. For e.g. St. Odiliënberg, South Netherlands, all the changes since the Middle Ages, like more land taken from the sea, from pasture to forests (and reverse). Up to the industrialization today. Even the main wind direction of today or the MWP may have changed in the LIA from SW to East.

As you can see in the above graph: South pole measurements are far more stable, especially over more years and reflect global CO2 levels, not local.

Stomata date have a better resolution, but don’t reflect global CO2 levels. It is that simple…

• Agnostic

“So why you believe that stomata data are accurate CO2 proxies for global CO2 levels?”

For the same reason that Mauna Loa is regarded as accurate representation of global CO2 levels: it is considered a well mixed gas in the atmosphere.

In actual fact, it is not AS well mixed as it is supposed, with individual readings from polar regions typically less than for regions closer to the equator.

But stomata and foraminifera (which are made up of shellfish and show similar variability when used as proxies for CO2) are far more useful as proxies for CO2 whatever their short comings because ice cores simply cannot capture resolutions that are meaningful in the context of modern warming and human emissions. Their problems are well documented. They are great for getting a picture of CO2 levels over millennia but they are simply unable to capture short term (approx 100 years or so) variability of atmospheric CO2.

This is constantly ignored in discussions about modern CO2 levels and putting our emissions and CO2 increase into context.

• David Appell

Agnostic wrote:
The CO2 had to come from somewhere: during the MWP it was as high as 380-390ppm before dropping to 285ppm. During the Bolling-Allerod CO2 increased to as much as 420ppm while temps were actually cooling, a break in the pattern of Temp leading CO2 which holds over all timescales.

Source?

Really would like to know.

• David Appell

Agnostic wrote:
Here are some papers showing CO2 levels comparable to today:
https://tinyurl.com/4923z3kn

Where in that paper?

Table 3 Aller0d 3.43 sample depth=343 (m I presume)?

For a mere 0.01 m?

Bølling–Allerød warming?

Proves nothing that is natural about the modern CO2 increase. Where do you suppose the 1.5 GtC that humans have emitted has gone?

• Agnostic

Appell: “Where in that paper?”

I quoted directly from the papers so you can do a word search.

“Bølling–Allerød warming?”

The Bolling-Allerod was the period that lead to the Younger Drays when the climate cooled, yet CO2 levels increased. It began with extremely rapid global warming that marked the end of the Older Dryas. It was accompanied by a large spike on CO2, which continued increasing even as the climate cooled, probably a lagged effect of the sudden warmth. According this paper:

…CO2 may have reached as much as 425ppm.

“Proves nothing that is natural about the modern CO2 increase.”

There isn’t good enough data to “prove” anything. What we CAN say, and what the paper that is the topic of this post is showing is that increase in CO2 cannot be driving the warming because the warming started first. It’s not the only paper to have pointed this out.

“Where do you suppose the 1.5 GtC that humans have emitted has gone?”

Into the biosphere. The biosphere expands and contracts depending on temperature and available CO2. That is what it did in the past and there is no evidence supporting that it is no longer happening now.

• David Appell

Agnostic wrote:
What we CAN say, and what the paper that is the topic of this post is showing is that increase in CO2 cannot be driving the warming because the warming started first.

What caused the warming first?

Do you wait for the temperature to increase before you start your car?

• Agnostic

Appell: “What caused the warming first?

Very likely the same factors that caused MWP, the Roman Warm Period and the Minoan Warm Period. If I could tell you exactly what they were I’d be up for a Nobel prize.

LOL. You are using an argument from ignorance to re-write reality. Can’t find your left shoe? Therefore left shoes don’t exist.

• Regarding the William Nordhaus video presentation, some comments by Ross McKitrick:

“And what would be a climate policy that we could confidently say would be consistent with making people better off around the world over the next 80 years, all things considered?

There aren’t many economists that think about it in that framework. One one of them who does is William D. Nordhaus who won a Nobel Prize in 2018 for his work in climate economics. A lot of the activist crowd were jubilant, thinking finally the economists have noticed climate change. And look at William Nordhaus: He’s an advocate for carbon taxes he won the Nobel Prize.

They don’t want to mention the fact that his modeling work showed that: We should do a bit of mitigation to eliminate some of the lowest value activities that generate greenhouse gas emissions, but otherwise the optimal policy is just to live with it and adapt to it.

And that’s the upshot of his modeling work and it’s been a very robust result over the 20 or so years that he’s been doing this modeling work. And it convinced the profession enough that his papers are in the best journals and he won a Nobel Prize for it.

Yet as I say the implications are lost on people including a lot of people in this climate economics field that you refer to. Who somehow think the fact that William Nordhaus got the Nobel prize in economics means we should all rush to net zero, even though his own analysis would say absolutely not. That result is not defensible and would make us incomparably worse off and be worse than doing nothing; be worse than just ignoring the climate issue altogether and pursuing economic growth.”

Really would like to know.”

The elephant in the room with an eerily wiggling trunk is the carbon sequestered in the Tundra. It is a large reservoir of carbon that no one seems to want to acknowledge.

• David Appell

Agnostic wrote:
The CO2 had to come from somewhere: during the MWP it was as high as 380-390ppm before dropping to 285ppm.

Where are these data?????

64. Peter Andersen

All of the critiques of Demetis relie on the fract that the NET netural feedback to increasing atmospheric CO2 is negative. The argument being that the human CO2 sources are conter-acted by the the negative feedback resulting in a atomospheric CO2 concentration less than half the extected.
But this argument ignores the influence of temperature on the individual natural sources and sinks. An increase in temperature might very well tent to increase the net natural source of CO2 and
even be more important than the human CO2 source.

• Peter,

The temperature influence on CO2 levels is known:
between 3 ppmv/K and 16 ppmv/K, from months to multi-millennia.
Only in the past 170 years, CO2 increased with 110-120 ppmv/K. That is not caused by any known physical process.
Over the same time span humans released some 200 ppmv. If that didn’t cause the bulk of the increase. what then else and where has that gone?

65. What an interesting article and what a pleasure to read expert people responding to a subject they know well. Good debate and thanks to one of the authors participating and defending their position.

We shouldn’t forget that warm and cold periods have waxed and waned throughout the Holocene without much change in C02 concentrations. That has brought with it periods of substantial greening, as occurred with such peoples as the Romans, whereby Carthage and North Africa was their breadbasket, in contrast to today.

66. And what is it that’s causing the warming?

It is the natural cycles described by Millutin Milankovitch.

Only their graphs should be read reversed.

https://www.cristos-vournas.com

• The Original Milankovitch Cycle states:

“You get an interglacial when the Summer is warm enough to melt the snow that fell during the Winter.

You get a glacial period when there is not enough summer heat to melt the snow. Then each year the thickness of the snow increases until you have new ice sheets.”

The Reversed Milankovitch Cycle states:

You get an interglacial when Winter on North Hemisphere occurs close to Earth’s Perihelion. The Southern Hemisphers’s vast oceanic waters are tilted towards the sun, when Earth is at its closest to the sun.

Thus, as it occurs in our era, during the North Hemisphere’s warmer Winter, the very much hotter Southern Hemispher’s SUMMER oceanic waters are heavily accumulating, and that is why we observe the current Global Warming.

https://www.cristos-vournas.com

• Christos, I appreciated your earlier point about all CO2 sources required to support the level of atmospheric concentration at any point in time. Ed Berry made this point in an Epoch Times article in this way.

He explained that when you look at the flow of carbon dioxide—”flow” meaning the carbon moving from one carbon reservoir to another, i.e., through photosynthesis, the eating of plants, and back out through respiration—a 140 ppm constant level requires a continual inflow of 40 ppm per year of carbon dioxide, because, according to the IPCC, carbon dioxide has a turnover time of 3.5 years (meaning carbon dioxide molecules stay in the atmosphere for about 3 1/2 years).

“A level of 280 ppm is twice that—80 ppm of inflow. Now, we’re saying that the inflow of human carbon dioxide is one-third of the total. Even IPCC data says, ‘No, human carbon dioxide inflow is about 5 percent to 7 percent of the total carbon dioxide inflow into the atmosphere,'” he said.

[Today’s level of nearly 420 ppm means that 120 ppm of inflow is required. So that would be 6 ppm of FF (5%) and 114 of natural emissions.

So, to make up for the lack of necessary human-caused carbon dioxide flowing into the atmosphere, the IPCC claims that instead of having a turnover time of 3.5 years, human CO2 stays in the atmosphere for hundreds or even thousands of years.

“[The IPCC is] saying that something is different about human carbon dioxide and that it can’t flow as fast out of the atmosphere as natural carbon dioxide,” Mr. Berry said. “Well, IPCC scientists—when they’ve gone through, what, billions of dollars?—should have asked a simple question: ‘Is a human carbon dioxide molecule exactly identical to a natural carbon dioxide molecule?’ And the answer is yes. Of course!

“Well, if human and natural CO2 molecules are identical, their outflow times must be identical. So, the whole idea where they say it’s in there for hundreds, or thousands, of years, is wrong.”

• David Andrews

Ron,

Of course CO2 molecules from human sources and from natural sources behave the same. This is one of Berry’s standard straw men. Nothing in the simple analysis showing definitively that the combined land/sea carbon reservoir has been a net sink for the last 60 years and longer (but not always in the geological past) assumes “human” and “natural” carbon behave differently.

Atmospheric carbon from whatever source mixes with land/sea carbon on a time scale of about a decade, and that is where Berry, like Harde and Salby and Skrable go wrong. They all focus on the “human carbon” vs “natural carbon” composition of the present atmosphere, and find the “human” part small. That is no surprise, because it has mixed with the much larger land/sea inventories. Mixing prevents the source of atmospheric CO2 growth from being inferred from the present atmosphere’s composition.

But there is indeed a difference between a flux of carbon into the atmosphere from, say, outgassing oceans and a flux of carbon from a coal fire. In the former case, that carbon had only recently been absorbed from the atmosphere. It is part of the fast carbon cycle. It was just passing through and did not add to the inventory of the fast cycle. (If oceans were outgassing ancient carbon, the carbon’s radiocarbon signature would show it.) In the coal burning case, carbon that had been sequstered for millenia is being added to the fast carbon cycle, first to the atmosphere and then distributed to land/sea. It is devoid of radiocarbon. It is the TOTAL carbon in the fast cycle that may take a long time to subside if and when fossil fuel contributions are zeroed out, though exacly how long is disputed. Fossil fuel burning adds to the fast cycle; ocean outgassing does not.

If you want to challenge the consensus, please understand it first, and be cautious about using Ed Berry and the Epoch Times as your authority.

• IPCC disagrees with you, why don’t you straighten them out and stop stalking me?

The removal of human-emitted CO2 from the atmosphere by natural processes will take a few hundred thousand years (high confidence). Depending on the RCP scenario considered, about 15 to 40% of emitted CO2 will remain in the atmosphere longer than 1,000 years. This very long time required by sinks to remove anthropogenic CO2 makes climate change caused by elevated CO2 irreversible on human time scale. {Box 6.1} Source: om Chapter 6 Working Group 1 AR5

• I’m not surprised by Epoch Times interest in this. So many people are tired of the relentless greenhouse gaslighting, they will look far and wide for some straight talk.

• David Andrrws

Ron,
OK, you got me.  Replace “human-emitted carbon “ with “carbon inventories raised by human emissions “ and everyone is happy.

Yes, I am picking on you to see if I can find one contrarian capable of understanding, or willing to admit understanding, that simple elephant in the room argument which I won’t repeat.  Guess I will have to look elsewhere.

• Ron,

“Ed Berry made this point in an Epoch Times article in this way.

He explained that when you look at the flow of carbon dioxide—”flow” meaning the carbon moving from one carbon reservoir to another, i.e., through photosynthesis, the eating of plants, and back out through respiration—a 140 ppm constant level requires a continual inflow of 40 ppm per year of carbon dioxide, because, according to the IPCC, carbon dioxide has a turnover time of 3.5 years (meaning carbon dioxide molecules stay in the atmosphere for about 3 1/2 years).”

Ron, here it is what I think about it:

The GLOBAL equilibrium level in the atmosphere is 400 ppmv.
On the other hand, Henry’s law has to do with the gases/liquid equilibrium in a closed volume.

Atmospheric CO2 equilibrium with oceanic waters has similar dependencies as Henry’s law, dependencies on CO2 partial pressure in the atmosphere, and on the temperature of the water and the temperature of the atmosphere – to mention few of the major factors.
Henry’s law cannot be applied as it is in the case of GLOBAL atmospheric CO2 equilibrium with oceanic waters.

In Henry’s law estimation of “the equilibrium CO2 level in the atmosphere would be 295 ppmv per Henry’s law.” there is only one temperature plays role.

In the case of atmospheric CO2 equilibrium with oceanic waters we do not have a fixed average temperature, what actually we are dealing with is a much more complex phenomenon there.

That is why I insist “The GLOBAL equilibrium level in the atmosphere is ~400 ppmv. ”

https://www.cristos-vournas.com

• David Appell

Ron Clutz wrote:
I’m not surprised by Epoch Times interest in this. So many people are tired of the relentless greenhouse gaslighting, they will look far and wide for some straight talk.

The Epoch Times is a worthless rag:

“The Epoch Times is a far-right[1] international multi-language newspaper and media company affiliated with the Falun Gong new religious movement.”
https://en.wikipedia.org/wiki/The_Epoch_Times

Not surprised Ed Berry wrote for them. He is a sad & deluded man who has turned against all his scientific training in order to serve his personal anger and disillusionment.

67. Reply to Robert Cutler, https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993975

“The results […] confirm that temperature and co2 are coherent to some degree, and also confirm Demetris’ result that temperature leads co2 by 6 months — at least over the time scales for which we have measured co2 data. […] I ran the experiment again for NH and SH data with the same delay result as for global temperature.”

Thanks so much, Robert. I am happy and grateful for your independent confirmation of our results by a different method. This is something substantial, in line with our view that science should rely on facts manifested in data, rather than imaginative speculations. And you strengthen our conclusions by showing that all data series, whether global or hemispheric, exhibit the same behaviour. This agrees with the result we report for the South Pole.

Furthermore, your remark “at least over the time scales for which we have measured co2 data” agrees with ours (p. 8 of our paper): “Overall, our results in this paper are those allowed by the available data at the time periods and timescales resolved by those data—more than 6 decades at the monthly scale. What would happen at other times—or if the data sets were longer and would resolve intermediate or even longer timescales—we cannot tell. The climate system is too complex to allow for hasty generalizations.”

But those claiming that, for timescales (a) longer than those allowed by the >60 years long instrumental data sets and (b) shorter than those allowed by paleoclimatic proxies, there is a reversal of causality, have to prove that this reversal exists. And to prove it, they not only need to invoke correlation or, even worse, invoke popular narratives. They need to deal with the necessary condition of time precedence of cause from effect.

• Thank you for your kind response, Demetris.

For those that might not understand why the phase response is a sloped line, the answer is very simple. A fixed delay represents a different amount of phase shift at different frequencies. For a one-year cycle, six months is a 180 degree phase shift. For a two-year cycle, the same delay is only 90 degrees. For a four-year cycle, the delay is only 45 degrees. The negative slope is because I’ve treated the temperature as the driving function, so the output, co2, is behind by, i.e. negative phase. If the slope had been positive, the temperature would have been driven by co2.

• Robert,

I didn’t use any frequency analyses in the past 60 years, as my job had quite different (pure technical/chemical) problems…

But I always wondered what the result would be of a frequency analyses if you have two independent variables, one with a huge slope and zero variability and another with a lot of variability and zero slope, resulting in a dependent variable with a lot of slope and much variability…

In this case:
How can you separate the increase in CO2 between temperature with a very small slope and a lot of variability and human emissions with about twice the slope and hardly any variability?

68. Thank you Agnostic! I couldn’t say it better than you did in https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993988

69. Ireneusz Palmowski

The Paper and your Comment Judith, shows a fundamental misunderstanding of systems analysis and resulting modelling.

A system analysis distinguishes between:

Forcing: The Sun, Burning of fossile fuels
State variables: CO2 in atmosphere, temperature, Cloud cover
Processes: Photosynthesis and respiration, exchange with the ocean.
Some processes are coupled, which e.g. means that CO2 is affecting temperature, and temperature affects CO2 concentrations

• Agnostic

“The Paper and your Comment Judith, shows a fundamental misunderstanding of systems analysis and resulting modelling.”

No it doesn’t. It is establishing a causal relationship based on available data. There is no dispute (or discussion) about the radiative effect of CO2, merely that CO2 lags temperature on all timescales so treating it as a forcing for that temperature change is wrong because it causally the wrong way around. TBH, that ought not be controversial but here we are.

• Agnostic,

The fundamental error is that the findings are only true for the lead/lag of the variability around the trend, but completely wrong for the trend itself:
All the variability is in the net sink (not source!) rate of CO2 into nature, while sinks are increasingly negative and temperature is slightly increasing over the same time 60+ years time span…
Thus temperature is NOT the cause of the increase.

• Agnostic

“All the variability is in the net sink (not source!) rate of CO2 into nature, while sinks are increasingly negative and temperature is slightly increasing over the same time 60+ years time span…
Thus temperature is NOT the cause of the increase.”

No – this is where you are completely wrong.

The source is ALSO variable. Highly variable. The sinks which you describe as “variable” are ALSO sources, they are interdependent and non-linear in their relationship.

During the growing season, some of the growth fixed via photosynthesis is trapped and some decays during the winter. How much decays is predominantly temperature dependent. The is why you see CO2 follow temperature on ALL timescales that we reliably measure.

• Agnostic,

I did write NET sink rate, it doesn’t matter that the variability is caused by the sinks or the sources or as is mostly the case, by both.

All what matters is that the +/- 1.5 ppmv/year variability indeed is caused by the +/- 0.5°C/year temperature variability, positive with temperature, while the trend in uptake is negative with temperature:
from -0.5 ppmv/year to -2.2 ppmv/year over the past 60+ years while there is a slight positive trend in temperature.
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8.jpg

Thus temperature is NOT the cause of the increasing trend in CO2 sinks and by extension, not the cause of the bulk of the increase in the atmosphere, as that is not more than 13 ppmv since the Little Ice Age.

My point is that the authors expand the short-term variability (“noise”) analyses, which are completely right, to the trends, which one may not do, as variability and trends have different causes…

• Agnostic

“as that is not more than 13 ppmv since the Little Ice Age.”

That again is where you are wrong. The high resolution records show much greater variability than that – up to 100ppm in some cases, in less than 100 years. If it is possible then it why would that not be possible now?

71. Agnostic

Thank you for an excellent paper and discussion on something that as been bugging me for years.

People are asking “if not from humans where is the extra CO2 coming from?”

Apart from the argument from ignorance, there is the causality argument which simply cannot be ignored:

– CO2 lags temperature on all timescales we can measure.

Unless you are disputing that, then it has to be understood that CO2 is a feedback not a forcing of the temperature. If previous warm periods showed a corresponding increases in CO2, then the same question has to be asked “where did the CO2 come from and go to?”

https://www.sciencedirect.com/science/article/pii/S016819232300254X

“Soil respiration in terrestrial ecosystems is critical for assessing the net ecosystem carbon (C) balance, because it represents the second largest global C flux (100 Pg C yr−1) between ecosystems and the atmosphere (Bond-Lamberty et al., 2018). This amount is more than 10 times what is currently produced by fossil fuel combustion. Thus, even a small change in soil respiration could substantially affect current changes in atmospheric CO2. Rising atmospheric CO2 levels can enhance the greenhouse effect, likely resulting in global warming. Global warming can substantially stimulate soil respiration, leading to a greater release of CO2 into the atmosphere.”

Additionally, the Carbon cycle is vastly – vastly – more complex than this discussion has touched on or seems to be generally appreciated. It subsumes our contribution.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213238/

Processes that release C into the atmosphere (biodegradation) are far more temperature dependent than processes that fix it (photosynthesis). So there is already a systematic imbalance regardless of anything we do. It is not just a linear “budget”.

During cooler periods, the rate at which CO2 is removed is greater than the rate at which it is released, leading to lowering of CO2 in atmosphere such as LIA. During periods of warmth, especially winter, more CO2 is released than is fixed leading to an increase. But the relationship is not linear.

As more CO2 is available, the transient biosphere expands and grows more vigorously. Some is trapped and some is released at the end of the season. How much is released is dependent on warmth (and to a lesser extent moisture in soils).

We hear the biosphere being described as a “net sink” which is growing because humans emit more C than is remaining in the atmosphere. But it is faulty thinking.

If we did not contribute, then atmosCO2 would still go up, making the biosphere a “net source”. That’s because the biosphere expands and contracts depending on how much CO2 is available and how warm it is. The CO2 comes from trapped sources particularly in the soils, released by increased temperatures which is a much larger overall source than human emissions.

IMO, it is better to think of carbon sources and sinks as dynamic reservoirs that are never perfectly in balance and which have a non-linear relationship with each other. We contribute to the source side, but the biosphere can tell the difference between man’s CO2 and naturally emitted, so characterising it as “budget” is where the confusion arises. The “budget” is always changing in non-linear interdependent way. It is not fixed.

• Agnostic:

CP2 lags T over all time scales, except for the past 170 years, where CO2 leads T.

The authors only proved that T variability around the trend leads CO2 variability around the trend and then applied that to the trends itself, which you may never do that, as the cause of the trend is completely different from the cause of the variability…

The short term CO2/T ratio is:
-5 ppmv/K for seasonal variability
3-4 ppmv/K for 2-3 years variability
5-16 ppmv/K for centuries to multi-millennia

110-120 ppmv/K for the past 60-170 years.
The latter is physically impossible and the authors have not supplied a satisfactory answer where that extra CO2 comes from, neither where the 200 ppmv human emissions did go over the same time span.

Then:
“If we did not contribute, then atmosCO2 would still go up, making the biosphere a “net source”.”

Which is impossible: nature is a net sink in ratio to the extra CO2 in the atmosphere. Currently about 120 ppmv above equilibrium, leading to about 2.4 ppmv/year net uptake in oceans and vegetation.

If humans stop any emissions today, the first year, the net sink would remain the same at 2.4 ppmv/year, as the atmospheric level still is 120 ppmv above equilibrium.
The second year, that is 117.6 ppmv and a net sink of 2.35 ppmv/year, etc… until the equilibrium of 295 ppmv gets reached +/- the natural variability around that equilibrium.
The e-fold decay rate is for a linear process and in this case is about 50 years (2%/year of the disturbance) or a half life time around 35 years.

• Agnostic

“CP2 lags T over all time scales, except for the past 170 years, where CO2 leads T.”

No it doesn’t:

CO2 lags Temperature an ALL timescales, including modern timescales, hence the questioning of causality of modern CO2 increase and temperature.

The relationship is not perfect though. There are cases where temp has increased and CO2 has not, or even where CO2 has increased and temperatures have fallen. To an undefined amount, it is nearly ALWAYS the case that temp leads CO2, and that includes the last 170 years. I have not seen reliable data that supports that conclusion.

• Agnostic

“The latter is physically impossible and the authors have not supplied a satisfactory answer where that extra CO2 comes from, neither where the 200 ppmv human emissions did go over the same time span.”

They do not have to.

They are showing that the causality implies it is temperature that causes CO2 to change.

Ferdinand you have to grapple with this, you can’t just ignore it. Statisticians will tell you in detrended data, you can’t claim something is causing something else if the changes occur after it. These guys are not the only ones to say this.

https://tinyurl.com/993xu7jf

“The maximum positive correlation between CO2 and temperature is found for CO2 lagging 11–12 months in relation to global sea surface temperature, 9.5–10 months to global surface air temperature, and about 9 months to global lower troposphere temperature”

On top of that, there are plenty of stomata and foraminifera proxy’s showing high atmospheric CO2 variability in warm periods during the holocene, with CO2 levels comparable to today. Where did the CO2 during THOSE periods come from?

• Agnostic,
You appear to have removed the trend, so your plot does not somehow refute the point that Ferdinand was making:

The authors only proved that T variability around the trend leads CO2 variability around the trend and then applied that to the trends itself, which you may never do that, as the cause of the trend is completely different from the cause of the variability…

• Agnostic

ATTP: “You appear to have removed the trend, so your plot does not somehow refute the point that Ferdinand was making:”

Yes it does. That’s because you detrend in order to compare other important information, in this case causality. In the detrended data set you can see clearly that changes in temperature are FOLLOWED by changes in CO2.

This occurs over ALL time scales. Yearly, decadal, centennial etc. You can see this in high and low resolution proxy data. Ferdinand is trying to make a distinction between short term fluctuations and long term trends of CO2 and temp. But clearly similar processes involved in the short term processes are involved in longer term ones as well.

We add to the reservoir of carbon sources, which fluctuate in size from year to year, decade to decade, century to century. The sinks ALSO fluctuate at different rates, that’s because they are governed by different processes.

Sources are governed more by temperature than are sinks. It is not a fixed budget.

• In the detrended data set you can see clearly that changes in temperature are FOLLOWED by changes in CO2.

Yes, this is not a surprise. It is well understood that the variability around the trend is driven by temperature variations (the physical processes are changes to the solubility of CO2 in the oceans and changes to vegetation in the terrestrial biosphere). However, this does not mean that the long-term trend (i.e., the one since about the mid-1800s) is a response to changes in temperature. It is very clear that this long-term trend is a consequence of anthropogenic emissions of CO2.

• Agnostic,

Yes it does:

In your graph, as ATTP said, you simply removed the trend, so your graph only shows that temperature variability causes the variability in CO2 rate of change (factor 3.5 for ppmv/K), but T is certainly NOT the cause of the CO2 trend since 1958! Neither in the variables, nor in the derivatives.

That is the crux of the matter in this discussion: the whole calculation shows that the variability in CO2 rate of change is caused by temperature rate of change, which nobody disputes, but then applies that to the trend, while there is hardly a trend in temperature (and none in the derivatives) and there is one in CO2 and its derivatives and twice as much in human emissions.

• Agnostic,

All what the authors and other statisticians like Humlum have proven is that T variability causes CO2 variability around the CO2 trend, with a maximum of +/- 1.5 ppmv around a 100 ppmv trend.

Nobody did prove that the 100 ppmv trend in the past 60+ years is caused by temperature, as that is physically impossible: there is no known natural source than even can provide such an amount of CO2 in such a short time period (except for a meteor impact).

Natural variability in net sink rate over the past 60+ years was not more than +/- 1% of the natural in/out cycle, which for a bunch of natural processes is a very small variability, but that is what the data show.

Then, you may be convinced that in the past some proxies show the real CO2 variability, while ice cores are “unreliable”.

In reality, ice cores with extreme differences in temperature and accumulation rate (thus resolution), all show the same CO2 levels within +/- 5 ppmv for the same time period. Including an overlap of ~20 years (1958-1978) between the Law Dome ice core and direct measurements at the South Pole:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_sp_co2.jpg
Within one ice core the repeatability of CO2 is +/- 1.2 ppmv at the same depth.

Antarctic CO2 measurements show near global CO2 levels and so do ice cores, be it mixed over several (8 to 600) years.
For the MWP, the resolution is about 20 years.

Other “high” measurements are from proxies which show local CO2 levels and have far more problems than ice cores…
Stomata data e.g. are calibrated over the past century against… ice cores, firn and atmospheric data…

If the stomata data show a different average over the time span of the ice core resolution, then the stomata data are wrong and need recalibrated to the ice core data, not the other way out…

BTW, do you have a reference to the high MWP CO2 levels?

• If the global temperature increases, the equilibrium point of CO2 exchange between ocean and atmosphere will shift towards CO2 moving from the ocean to atmosphere. This isn’t a binary relation. Most of the CO2 increase may well be from man-generated CO2, but not all of it. Some will come from the ocean.

• Jim2,

Indeed the temperature increase of 0.8 K since the depth of the Little Ice Age (depending of which reconstruction you like…) is good for about 13 ppmv increase in the atmosphere. The rest of the 135 ppmv increase comes from human emissions.
Or about 10% natural (temperature), 90% human…

• Agnostic

Ferdinand:

“Nobody did prove that the 100 ppmv trend in the past 60+ years is caused by temperature, as that is physically impossible: there is no known natural source than even can provide such an amount of CO2 in such a short time period (except for a meteor impact).”

No that simply isn’t true. There IS a known source, the same source that caused CO2 variability in other epochs. It’s called the biosphere.

The crux of the matter is the notion that there is carbon “budget” which is fixed. It is NOT fixed.

In past epochs CO2 has varied by as much as 100ppm in as little as 100 years. There is plenty of high resolution proxy data to support that.

CO2 lags temperature over ALL time scales INCLUDING centennial scales which is what you are suggesting is different this time around because of emissions. But it is not. Temperatures began to increase BEFORE atmospheric CO2 increased significantly and BEFORE mans contribution could have caused it. Causality is the wrong way around. I’ve long noticed this and it has always bothered me.

Concentrating on soils for the moment, CO2 and methane is produced during degradation of biological matter. There are numerous papers showing different bacterial processes, mesophilic and thermophilic processes.

“Temperature is one of the most important factors affecting microbial growth and biological reactions.”

https://pubmed.ncbi.nlm.nih.gov/15142802/

You will recall that tree rings indicate periods of warmth and are used as a proxy for temperature, but the main reason for that during warm periods there is more CO2 about. Enzymes involved in photosynthesis are also thermophilic but to the extent microbes that break down organic matter are.

There is therefore an imbalance. During COOLER periods, degradation slows MORE than photosynthesis. This traps CO2 and atmos CO2 decreases. This is both a transient effect (seasonal) and long term. The residence time for trapped carbon varies hugely between various environments, from a few years to 250 years.

During warm periods, carbon trapped in soils is released faster than photosynthesis can fix it, and atmospheric CO2 increases. There is dynamic interplay since as the biosphere expands and contracts with viable CO2.

We know for SURE that this happens because those processes has been the source of energy for 200 years of modern civilisation. And you can see it happening on all timescales we can reliably measure.

All that happens with our contribution, is that it causes the (especially transient) biosphere to expand by a little bit more, but were we not emitting CO2, CO2 would still be increasing in line with CO2 increases during warm periods in other periods of the holocene.

To reiterate, the SOURCE for increased carbon is the huge carbon reservoir primarily in soils. It is not a fixed budget – it expands and contracts depending on temperature.

• Agnostic,

“No that simply isn’t true. There IS a known source, the same source that caused CO2 variability in other epochs. It’s called the biosphere.

The crux of the matter is the notion that there is carbon “budget” which is fixed. It is NOT fixed.”

I never said that there is a fixed natural carbon “budget”.
All I said is that the whole biosphere is a net increasing sink for CO2. Proven by the oxygen balance:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
See Fig. 7, last page.

Thus whatever bacteria, insects, trees, cows or whatever natural sink or source did do over the past 60 years, the biosphere did absorb more CO2 than it released. Thus NEVER can be the cause of the CO2 increase in the atmosphere, at least not in the past 60 years.
Or by extension the past 170 years, as increasing temperatures over periods more than 3 years mean more plant growth than decay…

The natural CO2 level in the atmosphere for the current average ocean surface temperature would be 295 ppmv with a maximum change of 16 ppmv/K over the past 800,000 years, per Henry’s law. The 415 ppmv as seen in today’s atmosphere is not natural and caused by our ~200 ppmv emissions since 1850.

• Agnostic

” never said that there is a fixed natural carbon “budget”.
All I said is that the whole biosphere is a net increasing sink for CO2. Proven by the oxygen balance:”

Biosphere is only a “net sink” because we consider emissions to push that balance “over-budget”. But it is faulty way to think of it. If there were no emissions the biosphere would be a net source.

Ferdinand, the biosphere does not care whether a CO2 is emitted naturally or from human emissions. It expands when it is warm and it contracts when it is cool. Think of the biosphere is an interdependent non-linear system emitting and capturing CO2. We are small player in that. If there is more CO2 about then the biosphere can expand. That is why CO2 is pumped into commercial greenhouses.

The oxygen balance does not prove that emissions caused the CO2 to rise in the atmosphere. All it proves is that the overall carbon cycle is larger – but you would expect that if the system is dynamic, which it is.

I think we need to get away from the idea of a “budget” and using “net” source and sink. It’s the wrong conceptual model. Think of it as a reservoir with in-flows and out-flows moderated by temperature.

• Ferdinand, you said: “… there is no known natural source than even can provide such an amount of CO2 in such a short time period …”

Do you have reliable numbers for the emission of CO2 and CH4 from the Tundra?

• David Appell

Ferdinand Engelbeen wrote:
CP2 lags T over all time scales, except for the past 170 years, where CO2 leads T.

CO2 also leads T when it’s independently ejected into the air, like in the PETM via volcanic eruptions.

And like today.

• David Appell

clydehspencer wrote:
Do you have reliable numbers for the emission of CO2 and CH4 from the Tundra?

Do you?

Even a Fermi calculation?

Are you aware of how the atmospheric increase in ratios of C12, c13 and C14 show the added atmospheric CO2 is due to long-buried carbon?

If not, get up to speed. 30 years too late. Learn the science before questioning science determined long ago.

• It has been a big pleasure to “meet” you here, Agnostic! I appreciate your deep knowledge on the carbon cycle. Even though I am not an expert on that issue, which you are, I believe I can tell the difference between scientific and childish arguments. Also, I can easily discern those who (while accusing Judith for Appeal to Authority) feel to be authorities themselves, so as we have to accept their judgement and statements about “fundamental errors”, “absolutely not caused”, “paper makes no sense”, “pretty obvious … simply wrong” , “be retracted”, “tarnishes the reputation of Ms. Curry”… Without feeling obliged to specify which error they find in the paper and where exactly…

I am particularly glad that you identified the robustness of our method for detecting causality. This was the focus of our method and our papers—not to analyse the carbon cycle. And this is reflected in the structure of the body paper. But in order to address the review comments, we had to add the Appendices and their discussion in the body of the paper (we clearly state that in its Acknowledgements), including that on the carbon cycle. We understood the reviewers’ concerns: The result we found seems weird to most people, as not complying with the official narrative. For this reason, we had to delve into issues which were not included in our initial plan, and try to justify our finding. A finding that, while opposing the popular beliefs, it does not oppose logic. Well, this eventually added value to the paper. And I am so glad that you, a knowledgeable person on carbon cycle, confirms that we did not err in our considerations, analyses and conclusions on that issue.

I learned a lot from your insights, thank you!

PS. Of course, given the lack of arguments against our analyses, I fully understand the clearly stated aims to enforce retraction of our paper(s), as well as the accusations to Judith for triggering the discussion–instead of following the politically correct tactic of silencing or eliminating “nonconforming” scientific views and analyses. This is a sign of intellectual decadence. As we have written in our paper http://dx.doi.org/10.5194/hess-25-2419-2021 (not retracted–yet :-), “Signs of similar decadence are also present in our era, particularly in the Western World, where ideas are being replaced by ideologies and reason by stereotypes of “correctness”.

• Agnostic

I have read other similar papers that came to the same conclusion, one in particular by statistician. They were adamant that from a statistical POV you cannot claim causality the way round it is traditionally viewed.

I am NO expert on the carbon cycle, by any means. But it has been bone stuck in my head for a long time because I AM interested in paleoclimatological record. Ice core data is what is generally used to show that CO2 levels are at “unprecedented levels”, yet we know that ice core data is unreliable and too low resolution to speak about short intervals of warming of 300 to 400 years which we appear to be in.

High resolution proxies clearly show similar concentrations of CO2 in the atmosphere to today, yet that is not put into context. Where did THAT CO2 come from?

The other thing that bothers me is the “budget” approach to CO2 as if there was a fixed amount of C that can be released or absorbed yearly. Yet just the tiniest forays into biodegradation and soil hydrology shows how an incredibly complex and interdependent picture it is, and that’s to say nothing of the oceans.

As usual with climate science, conclusions are made to support a narrative or a pre-existing conviction and the complexity be damned.

• Then, you are a humble expert (meant one with humility, if my English betrays me), Agnostic! (And, by the way, I appreciate your Greek nickname…).

I second what you said about temporal resolution. I find it interesting that people (including in this thread, if I remember well) compare instrumental data at annual or monthly time scale with paleoclimatic data at a timescale of hundreds or thousands of years as if they were indeed comparable. I have tried to illustrate how misleading this is using data of one of the longest available instrumental time series, that of rainfall in Bologna, using annual and 30-year time scales. If interested, you may see my Figure 4 in the replies to reviewers of Round 1 (Author Response — not included in the paper per se) of my paper “Rethinking climate, climate change, and their relationship with water”, http://dx.doi.org/10.3390/w13060849 (the review archive is available online). After seeing this figure, imagine that the 30-years scale becomes a 1000-year one …

• Agnostic,

Even the worst resolution ice cores (Vostok with 600 years resolution) would show an CO2 increase of 135 ppmv in 170 years as a “peak” of near 40 ppmv in the ice core, which would certainly be noticed as abnormal in the 100 ppmv increase over 5.000 years from some 6 K in temperature increase.

There is no such peak in any ice core, while the high resolution Law Dome sees a dip of about 10 ppmv/K at the depth of the LIA around 1600:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg

If your stance against ice cores is based on what the late Dr. Jaworoski said, here my experience with his remarks:
http://www.ferdinand-engelbeen.be/klimaat/jaworowski.html

• Demetris and Agnostic,

Even if there are large differences in resolution between different ice cores and proxies, one item is conserved: the average over any time frame.

If there is a discrepancy in average CO2 level between a 20 year resolution ice core in the MWP and some (near) yearly resolution proxy which shows a much higher or lower CO2 level over any 20 years period, then one of them must be wrong.

Highly probable the proxy, as the ice cores do reflect the real atmospheric average CO2 level over any time frame within +/- 5 ppmv. Here the differences between ice cores with temperature differences between -20°C (Law Dome) and -40°C (South Pole core) and accumulation differences between a few mm per year (South Pole) and 1.2 meter ice equivalent (Law Dome) for the same average gas age over the past 1,000 years, with resolutions between 8 years Law Dome (DE08-1/2) and app. 400 years (South Pole):
http://www.ferdinand-engelbeen.be/klimaat/klim_img/antarctic_cores_001kyr_large.jpg

• Agnostic

Ferdinand:

There is plenty of evidence showing much higher variability of CO2 levels on the scale of what we are seeing today relative to ice cores. They are useful for timescales of millennia but not so great time scales of centuries. The problems are well documented.

“If there is a discrepancy in average CO2 level between a 20 year resolution ice core in the MWP and some (near) yearly resolution proxy which shows a much higher or lower CO2 level over any 20 years period, then one of them must be wrong.”

Not exactly. 20 year period is much too short. Even Law Dome, which is the highest resolution ice core, the firn layer is not reached until 90 years. Then there is the problem of diffusion, essentially acting as a low pass filter for any fluctuations of a scale of centuries.

The reason they are favoured is that they are contiguous, and stomatal proxies are not. But there is good agreement between the various stomatal and foraminifera CO2 proxies and they show very high variance, over short timescales of 100 years or so. The stomatal evidence for MWP show that CO2 reached a peak of up to 390ppm (some show over 400ppm) just as the LIA was getting under way and it fell from around 1500 to early 20th C. This again is temp leading CO2 not the other way around.

NB…all this is not to suggest that man has not had some influence on CO2 levels since industrialisation. It’s just my speculation but I think we might have been responsible for the difference between the peak following the MWP and current levels, so perhaps 20-30ppm. All I am saying is:

– high resolution proxies show atmospheric CO2 variance similar to current in previous ages
– there is no reason to suppose those processes are not at work today
– causality is almost ALWAYS temp leading CO2 on ALL time scales including since industrialisation. Warming began long before CO2 really increased.
– the carbon cycle is interdependent non-linear system that can be characterised as a reservoir rather than a limited budget. Carbon is trapped during cool periods and released in warm periods as per the proxy record.
– the paper under discussion is ONLY showing that causality is the wrong way around for emissions to be driving warming.

• Agnostic …

> IMO, it is better to think of carbon sources and sinks as dynamic reservoirs that are never perfectly in balance and which have a non-linear relationship with each other.

Good point. Thanks.

• I agree that this has been an interesting discussion that has expanded my viewpoints of the climate system, regardless of who is correct on each specific point.

What’s a forcing? IMO it’s a variable external to the system that can impact the system’s equilibrium, for example Milankovitch cycles. But even here the orbital influence can vary depending upon the system’s state, like whether the perihelion is in the southern or northern hemisphere winter, or how much ice albedo exists at that particular moment, or how thick the glacier is, or the altitude the glacier reaches to, or global conveyor, and other variables. We think of fossil fuel as a forcing because the source of the carbon was outside the system until humans dug it up. But even if we grant CO2’s radiative effects CO2 does not account for temperature swings in the Holocene, and not even of the warming of the last 150 years without assuming inherent positive feedbacks of 1.5X to 3X within the system.

The AGW concerned scientists argue that higher unexplained variability indicates evidence of higher feedbacks and thus higher sensitivity to forcing (like extracting fossil carbon). That could be the case but it also might be that there is simply poorly understood variability. If the establishment truly believed that unexplained variability, like the MWP and LIA, were evidence of higher feedbacks they would be promoting them rather than preferring to erase them.

It’s not accepted that CO2 drove global temperature in the Pleistocene or Holocene before fossil fuels. It is accepted that CO2 lags global temperature, both on the millennial scale, and now we see, on the annual scale. This certainly puts some burden on the AGW consensus to have independent proofs of causation.

• David Appell

Ron Graf commented:
It’s not accepted that CO2 drove global temperature in the Pleistocene or Holocene before fossil fuels. It is accepted that CO2 lags global temperature, both on the millennial scale, and now we see, on the annual scale.

OMG.

CO2 certainly had an effect during the Pleistocene, as a feedback to warming and cooling.

BUT TODAY: we’re pumping CO2 straight into the atmosphere.

We don’t wait for the temperature to increase before we do this.

So in this case, CO2 leads temperature.

It’s so completely obvious and simple, it’s amazing so many people can’t understand it.

• David Appel wrote: “CO2 certainly had an effect during the Pleistocene, as a feedback to warming and cooling.”

I am assuming you remember An Inconvenient Truth (2006). That Nobel Prize winning piece of science which claimed that CO2 concentrations could be superimposed onto the ice core chart of the Pleistocene, proving CO2’s control of temperature. Now you are admitting that Sir Al Gore was mistaken and all of the school children worldwide who have been shown the film were misinformed. Is that right? CO2 was just a feedback? Okay, how powerful of a feedback could it be if the surface temperatures had to warm for hundreds of years before CO2 got released from the oceans entering interglacials and conversely glaciation occurred suddenly while CO2 levels remained high for hundreds of years while Henry’s Law slowly went to work to uptake the CO2 in the slowly cooling oceans?

Remember, the more power you assign CO2 to explain the paleo temp chart the less you can assign to ice albedo and water vapor concentration change and other positive feedbacks.

Also, how does CO2 explain the wavy waterslide of the thermometer record compared to the atmospheric CO2 record?

Also, the global temperature and CO2 took a dive ~500 years ago and began to rebound ~330 years ago. Why?

Government funded climate scientists would these questions be erased from discussion. Why?

72. Below, I am making public my replies to another personal exchange with Ferdinand:

As per your scientific remarks, to avoid repetition I will focus on one I haven’t already discussed. Specifically, you say:

> …variability and trend have different causes…

1. Nature exhibits variability. The trend is a human invention. Not a scientific one — and not anything objective: if you change the beginning and ending points, or the mathematical expression, you get another trend. I have not seen a decent definition of a trend which could classify as scientific. The best I have seen is poetic: “A trend is a trend is a trend / But the question is, will it bend? / Will it alter its course / Through some unforeseen force / And come to a premature end?” (Sir Alec Cairncross, 1969, signing as “Stein Age Forecaster”). My coauthor and I have used this “definition” as a motto of our paper: “Projecting the future of rainfall extremes: better classic than trendy”, http://dx.doi.org/10.1016/j.jhydrol.2020.125005

2. In stochastics we may easily get rid of the nonscientific notion of a trend by using varying timescales. And then it enters the scene the Hurst-Kolmogorov stochastic dynamics. I am listing a few papers as an introduction to this behaviour:

— Fig. 1 in my paper “Nonstationarity versus scaling in hydrology”, http://dx.doi.org/10.1016/j.jhydrol.2005.09.022 , explains why we need long data series to make inference and how misleading our models can be, in absence of adequate data.

— My paper Hydrology and Change, http://dx.doi.org/10.1080/02626667.2013.804626 , explains the dominance of change in all natural processes, its different aspects with respect to timescale, and the Hurst-Kolmogorov dynamics–I hope in the simplest possible manner.

— The paper “Nature’s style: Naturally trendy” by the late Tim Cohn and by Harry Lins explains the dramatic impact on statistical inference of the neglect of this stochastic dynamics.

3. Why you claim that variability and trend (whatever the latter is–in my view is also variability at another scale) have different causes? They can well have the same cause. Our paper discussed here, and in particular its Figure 15, proves that they can have the same cause, with the longer term variability described by a function applying to a larger timescale. Notice that this function is also characterized by time precedence of temperature. Also notice that we do not propose this model as a decent one. We clearly say that it is a toy model. It serves our purpose to show that (a) our method can be further advanced in building a model, in addition to identifying causality and (b) the time precedence of temperature can also explain what you call “trend”.

4. We do not present our above toy model as a conclusive one. There is room to explore the data and mechanisms further, and make a better model. But a better model does not mean that we could arbitrarily replace what is seen in the data with arbitrary assumptions. In particular, we should respect the causality direction as given by the data. If you reverse the causality direction at longer time scales, you should first prove, based on data, that such reversal can be justified by the data.

• Dear Demetris,

I am not a Greek philosopher, just an engineer who in his (working) life had to do with brilliant people who from time to time needed to put again with their two feet back on the ground.

That being said, here the reactions in four parts…
————————————————————
Item 1. About to trend or not to trend…

You always said “let the data speak”.

Well the (trend (*) through the) data say that in 1960:
Human emissions: 1.2 GtC/year
Increase in the atmosphere: 0.8 GtC/year
Increase in temperature: 0.013°C/year

The data for 2020, 60 years later:
Human emissions: 4.8 GtC/year
Increase in the atmosphere: 2.4 GtC/year
increase in temperature: 0.013°C/year.

In 60 years time a fourfold increase in emissions, a threefold increase in residuals in the atmosphere for exactly the same temperature increase.
How then can the yearly increase in the atmosphere be caused by temperature?

(*) It hardly makes a difference if one uses the exact data from 1960 to 2020 and not the trended data, only there is more temperature induced “noise”:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em8.jpg

———————–

You have a point that a trend changes with the choice of a begin- and endpoint.
On the other side: trends can be statistically calculated, including error margins and statistic relevance including how much years is needed to emerge a relevant trend out of the noise.
In this case, the 60 years from 1960 to 2020 are more than enough to show that the trends are relevant…

• David Appell

Ferdinand Engelbeen wrote:
The data for 2020, 60 years later:
Human emissions: 4.8 GtC/year

No, human emissions for 2020 are about 10 GtC.

Getting the data right is a necessary first step in any analysis.

• David, indeed, units on the graph were ppmv/year not GtC/year of about half the GtC/year…

• Item 2. Trend vs. stochastic.

I fully agree that natural changes are stochastic in the case of short term temperature changes and short, up to very long term for precipitation.

Even for temperature, the (very) long term changes are in large part non-stochastic, but directly influenced by the Milanchovitch cycles. And many other “stochastic” events in temperature as introduced by (deep) ocean oscillations may be caused by calculable events (solar, lunar), only we don’t now the real causes up to know (and there is little research money for that).

And we have human emissions which are quite steadily increasing each year. That is a straight forward trend since 1750, without much variability (even hardly any from Covid). Hardly anything “stochastic” in the trend…

• Item 3. Different causes.

In the answer to Aubrin ( https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994056 ) I did show that the short term variability in CO2 response to T variability is caused by vegetation. That can be seen in the opposite CO2/d13C changes: vegetation CO2 changes and 13C/12C ratio changes do change in opposite direction when CO2 is taken away or released by vegetation. Here the graph:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_dco2_d13C_mlo.jpg

When temperature changes due to e.g. an El Niño, the Amazon dries out, releasing a lot of CO2. During the Pinatubo eruption, the temperature dropped, but more leaves could take up CO2 due to the scattered sunlight by the aerosols in the stratosphere.

Over longer time frames than a few years, increasing temperatures (and more CO2) increase plant growth, thus plants are not the cause of the CO2 increase over time frames of more than 3 years.

Over very long time frames, hundreds to hundred thousands of years, the 13C/12C ratio of the atmosphere hardly changes, as that is mainly caused by (deep) ocean temperature changes.

And over the past centuries, the human influence is quite visible in the 13C/12C ratio, both in the atmosphere (ice cores, firn, direct) and in ocean surface waters (coralline sponges):
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.jpg

Figure 15 is just curve fitting, which in this case is quite simple as the result is a simple slightly quadratic curve. Only there is an enormous difference in factor: factor 3.5 for short term variability, factor 110 for the 60-year trend. Not really believable

One can fit the increase in the atmosphere as good as a % of human emissions: a factor 0.53 since 1900 fits as nice. And much more plausible…

• Item 3.0 Different causes.

In the answer to Aubrin ( https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994056 ) I did show that the short term variability in CO2 response to T variability is caused by vegetation. That can be seen in the opposite CO2/d13C changes: vegetation CO2 changes and 13C/12C ratio changes do change in opposite direction when CO2 is taken away or released by vegetation. Here the graph:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_dco2_d13C_mlo.jpg

When temperature changes due to e.g. an El Niño, the Amazon dries out, releasing a lot of CO2. During the Pinatubo eruption, the temperature dropped, but more leaves could take up CO2 due to the scattered sunlight by the aerosols in the stratosphere.

Over longer time frames than a few years, increasing temperatures (and more CO2) increase plant growth, thus plants are not the cause of the CO2 increase over time frames of more than 3 years.

• Item 4.

In a question asked to Robert Cutler, he answers ( https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994045 ) that the signal of human emissions is suppressed by the signals from the temperature variability, because the variability of human emissions is too low.
The method used doesn’t allow for any attribution of the trends…

Thus as I repeatedly said, all what you have proven is that the +/- 3.5 ppmv/K variability around the trend is caused by temperature variability, but that doesn’t imply that the 90 ppmv increase 1960-2020 is caused by temperature.

That is the crux of the matter…

• Ferdinand,

You wrote: “In a question asked to Robert Cutler, he answers ( https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994045 ) that the signal of human emissions is suppressed by the signals from the temperature variability, because the variability of human emissions is too low.”

This is factually incorrect. I never attributed the trend to anything. Please correct your statement.

• Robert,

I did understand that the “signal” in this case is the variability of both variables, where the strong variability of the temperature suppresses the variability of the near zero variability in human emissions.
Which of course attributes all variability to temperature with a lag.
And that one can’t attribute the trends to one or the other in these circumstances…

Or my question remains the same:
Make a simple mix of two variables yourself: one variable with only a strong trend and no variability, just a straight line.
The other variable with no trend at all and the result of two repeating sinusoids of different length.
Add both variables together with some lag for the sinusoids and then give them the full frequency analysis treatment.

I wonder if the method will recognize that the full trend is from the first variable…

• David Appell

demetriskoutsoyiannis wrote:
The trend is a human invention. Not a scientific one — and not anything objective: if you change the beginning and ending points, or the mathematical expression, you get another trend.

Obviously.

That doesn’t make trends useless. There’s been a strong warming trend since 1975 — almost 50 years. Its uncertainty is reasonably small. It needs to be explained. Manmade GHGs are the only known reason for the warming. Importantly, that’s also the prediction.

• David, there was fast warming 1910-1945 hardly any CO2 increase and a slight cooling thereafter 1946-1975 with slightly increasing CO2.

As long as there is no explanation for the first warming and subsequent cooling (and no, aerosols are only a scapegoat), you can’t attribute all warming to CO2 alone…

• David Appell

Ferdinand Engelbeen wrote:
David, there was fast warming 1910-1945 hardly any CO2 increase and a slight cooling thereafter 1946-1975 with slightly increasing CO2.

There is an explanation:

2) clearing out of volcanic dust from 1250-1900
3) increase in CO2: for the early changes in CO2, the radiative forcing is linear, not logarithmic.

ln(C/C0) = ln[(C0+dC)/C0] = ln(1+dC/C0) =appx dC/C0

• David Appell

Ferdinand Engelbeen wrote:
….and a slight cooling thereafter 1946-1975 with slightly increasing CO2.

Come on, this has been discussed into exhaustion — it’s due to the rise in aerosols from vehicle emissions after WW2 and before the adoption of pollution controls on vehicles.

73. Joshua

Demetris –

> The trend is a human invention.

Indeed. So is the characterization of what “the data say” when they “speak.”

74. stevenreincarnated

It would take hundreds of years for the oceans to equilibrate with the added CO2 from burning fossil fuels and this would only remove about 80% of the anthropogenic CO2. The sinks just aren’t there for the increase to be natural even if mathematically possible. There is also an incredible lack of evidence that CO2 is the primary climate driver. So yes, that man is adding CO2 to the atmosphere is pretty solid. That CO2 is driving temperatures isn’t solid at all and that is the real problem since it is that premise that makes our would-be masters want to direct everything in our lives.

• Steven,

The 80% removal in equilibrium is what the IPCC’s Bern (and similar) model(s) say.

Fortunately for us, the deep oceans (and vegetation) keep on going to absorb our CO2, practically unrestricted until complete redistribution between all reservoirs at a half life speed of about 35 years.
If all human emissions are distributed in the deep oceans, that would increase the C content there with 1%. In equilibrium with the atmosphere that gets +3 ppmv above the current equilibrium of 295 ppmv, that is all…

The influence of CO2 on temperature indeed is much smaller than the IPCC’s models show…

75. If light water evaporates faster than heavy water, then heavy water will turn to ice or snow before light water. Does anyone know if that’s accounted for in the ice core records used for temperature?

• Agnostic

That’s how they determine temp from ice cores. O18 isotope is higher in layers that correspond to higher temps.

• Exactly the point.

• Carbon isotope ratios are used as an argument that the atmosphere is changing because of the burning of fossil fuels. However, I haven’t seen any research specifically about isotopic fractionation of out-gassing of CO2 from upwelling seawater, isotopic fractionation of respired CO2 from tree leaves/needles and roots, or selective use of calcium carbonate (calcite/aragonite) by calcifiers. There is a lot we still don’t have numbers for.

• Clyde, these are known for the seawater-air and reverse transitions: -10 per mil sea-air and -2 per mil air-sea, resulting in -8 per mil for a CO2 cycle that is in equilibrium.
As the ocean surface is between +1 and +5 per mil (due to organic life), the average in the atmosphere over the whole Holocene is -6.4 +/- 0.2 per mil.

Currently at -10 per mil thanks to human emissions. For vegetation, that is in average -24 per mil, near the same as for the current mix of fossil fuels at -26 per mil and the difference between these two can be seen in the oxygen balance… Then we have carbonates: one type was used as “standard” thus zero per mil: Pee Dee Belemnite (PDB) but nowadays there is fixed standard. Carbonates have about the same isotopic ratio as the surrounding waters, thus around 1-5 per mil.

• David Appell

clydehspencer wrote:
However, I haven’t seen any research specifically about isotopic fractionation of out-gassing of CO2 from upwelling seawater, isotopic fractionation of respired CO2 from tree leaves/needles and roots, or selective use of calcium carbonate (calcite/aragonite) by calcifiers.

That’s a statement about you, not science.

76. Richard Courtney

Dr Curry,

The above article addresses the question, “given two processes, how can we determine if one is a potential cause of the other? ”

I respectfully point out that it is coherence (n.b. not corelation) which provides the required determination because an effect cannot occur before its cause. And their coherence indicates that changes to atmospheric CO2 concentration (measured at Mauna Loa since 1958 )follow changes to global temperature. This was first determined by Kuo et al and published in Nature in early 1990.
(ref ‘Coherence established between atmospheric carbon dioxide and global temperature’; Kuo C. Lindberg C & Thomson D; Nature; February 1990
The abstract of their paper says,
“The hypothesis that the increase in atmospheric carbon dioxide is related to observable changes in the climate is tested using modern methods of time-series analysis. The results confirm that average global temperature is increasing, and that temperature and atmospheric carbon dioxide are significantly correlated over the past thirty years. Changes in carbon dioxide content lag those in temperature by five months.”

The finding of Kuo et al. that “Changes in carbon dioxide content lag those in temperature by five months ” is clear, and it induced two groups of follow-up studies by other workers. i.e.
(a) One group confirmed that the CO2 changes lag behind temperature changes but the length of the lag varies with distance from the equator.
(b) The other group also confirmed the coherence but argued that feedbacks in the climate system create the apparent lag of CO2 changes after temperature changes. (I regret that I doubt these arguments because understanding of such feedback mechanisms would enable construction of a time machine similar to that imagined by HG Wells, and there are no reports that members of the group have constructed such machines.)
Richard

• Yet this point is already well understood, and doesn’t refute the point that longterm rise in CO2 results in higher surface temperatures. By looking at the shorter timescale (which associates with bigger short term changes in CO2 and temperature, in which temperature causes locally big fluctuations) you miss that those signals aren’t generally cumulative, but the smaller year to year rises due to our emissions build up over time and lead to a positive correlation between CO2 and temperature on the longer timescale.

• Agnostic

No, that does not follow.

Longterm rise in CO2 should result in higher surface temperatures as you say, but this “should” be treated as a positive feedback, not a forcing.

Temperatures began to rise from around 1850 and more significantly from early 20th long before human emissions were significant, or CO2 increase in the atmosphere. Causality is the wrong way of you are claiming CO2 is the driver of the increase in temperature.

It’s not true that natural process increasing CO2 in the atmosphere are not cumulative, because the carbon cycle has long term processes and short term transient processes. Residence time for carbon varies hugely from different types of environments, from just a few years to 250 years. Processes that release CO2 from organic matter are more temperature dependent than processes that fix it. During cooler years CO2 is trapped, and warmer years it is released.

As a simple model, imagine a deciduous tree in a field. During the growing season it draws CO2 out of the air and water from the soil and produces foliage and grows slightly. The foliage drops to the ground during autumn and then decays, most of which will return to the atmosphere as CO2 and CH4. But some is fixed in the tree itself.

There is a big storm in winter, and the tree loses a branch. The branch represents years/decades of fixing carbon from the atmosphere, but now it begins the process of decay. It continues to release CO2 for a decade or more, but the rate at which it does this much more dependent on temperature than the processes that trapped it. It’s for this reason that we refrigerate food.

The foliage represent transient short term processes capturing and releasing CO2 into the atmosphere, the branch represents long term processes that release CO2 continuously over decades.

Fixing and releasing of CO2 are two processes that are not in balance, and this occurs over short time periods and long. And we see this in the stomatal record against long term temperature proxy record.

• Agnostic

And our burning of gas, oil and coal is just another one of those natural longer term carbon cycles.

• Thanks for this important information, Richard!
Demetris

• The rise in temperature to 1940 wasn’t monotonic, and it was mostly driven by a big El Niño surface T spike in the early 1940s.

• richardscourtney

Paul Roundy,
And the relevance of your comment about changes “in the 1940s” is what? As I said, Kuo et al. analysed the measurements at Mauna Loa analysed which did not start until 1958.

• Richard Courtney

Thank you for providing the reference to Kua et al. I don’t have access to Nature, but the abstract sounds very much like the approach I used here to validate the results described in this article. The only difference is that I found the delay to be six months, but then I have 30 years of additional data to work with. Perhaps I should stop complaining about the limited length of the datasets!

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-993850

https://judithcurry.com/2023/09/26/causality-and-climate/#comment-994045

• The only work that cites the work of Kua ea. is from Kaufmann and Stern (1997) and is titled:
“Evidence for human influence on climate from hemispheric temperature relations”
https://www.nature.com/articles/40332
with full access…

While it is mainly about the precedence of temperature changes between NH and SH, it uses CO2 emissions and sulfate emissions (which are antagonists for any temperature effects).

That ends with:

“This is consistent with the hypothesis that the south-to-north causal order is generated by the historical combination of greenhouse gases and tropospheric sulphates.”

While I doubt the result of any model based on sulfate aerosols, which is largely (ab)used as adjustment control to explain the 1946-1975 dip, the fact that they assume that CO2 influences T, despite the work of KUA e.a. is interesting to investigate further…

• richardscourtney

Ferdinand Engelbeen,
You assert, “The only work that cites the work of Kua ea. is from Kaufmann and Stern (1997) ”
If that wre true then so what? Kaufmann and Stern (1997) assessed coherence of CO2 changes between NH and SH hemispheres which is not relevant to coherence between CO2 at Mauna Loa and global temperature.
And the references provided in this thread demonstrate your assertion is not true.

• David Appell

Richard Courtney wrote:
Kuo et al and published in Nature in early 1990.
(ref ‘Coherence established between atmospheric carbon dioxide and global temperature’;

“On the causal structure between CO2 and global temperature
Adolf Stips, Diego Macias, Clare Coughlan, Elisa Garcia-Gorriz & X. San Liang , Scientific Reports volume 6, Article number: 21691 (2016).

“Abstract”
“We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. A significant but smaller information flow comes from aerosol direct and indirect forcing and on short time periods, volcanic forcings. In contrast the causality contribution from natural forcings (solar irradiance and volcanic forcing) to the long term trend is not significant. The spatial explicit analysis reveals that the anthropogenic forcing fingerprint is significantly regionally varying in both hemispheres. On paleoclimate time scales, however, the cause-effect direction is reversed: temperature changes cause subsequent CO2/CH4 changes.”

(emphasis mine)

• richardscourtney

David Appell.
Yoiu quote Stips et al. (2016) as saying,
“We use a newly developed technique that is based on the information flow concept to investigate the causal structure between the global radiative forcing and the annual global mean surface temperature anomalies (GMTA) since 1850. Our study unambiguously shows one-way causality between the total Greenhouse Gases and GMTA. Specifically, it is confirmed that the former, especially CO2, are the main causal drivers of the recent warming. ”
Firstly, I am interested to know how Stips et al. determined the annual greenhouse gas emissions “since 1850”; did they use a ‘crystal ball’?
Secondly, how did Stips et al. assess the reliability of their “newly developed technique” when there is no independent data set for it to assess or to use for calibration?
Importantly, I want a time machine, and time series analyses – such as that of Kuo et al. – demonstrate CO2 changes follow temperature changes: therefore, I ask why Stips et al. have not used their “unambiguous” understanding to construct a time machine?

• Note that we cited Stips et al. (2016) in both our first Royal Society paper (Revisiting causality using stochastics: 1.Theory, Proceedings of The Royal Society A, 478 (2261), 20210835) and our first Sci paper (Atmospheric temperature and CO₂: Hen-or-egg causality?, Sci, 2020). We showed that in Gaussian processes the method simply finds correlation, not genuine causality, of course. But most importantly, it does not mention at all the problem that high autocorrelations (as documented in both our papers) make the results spurious.

An independent critique of the method was provided by Goulet Coulombe P, Göbel M. On Spurious Causality, CO2, and Global Temperature. Econometrics. 2021; 9(3):33.

• Richard,

I don’t think this is one of the the follow-up papers you’re referring to, but there’s a 2009 paper by Jeffery Park: “A re-evaluation of the coherence between global-average atmospheric CO2and temperatures at interannual time scales”

A pdf of the paper is available here:
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2009GL040975

The core frequency-domain methodologies and results are similar to what I’ve shown here, namely six-months delay and sensitivity of ~3ppm/K. I’m not seeing their 90deg phase lag in the data I’ve used. Their exploration of temperature is much more extensive.

Thanks again for the reference to Kuo. et al.

• richardscourtney

Robert Cutler, Thanks for the link to Park’s 2009 paper.
I notice that park says, ” Coherent
annual-cycle fluctuations in CO2 and temperature are
evident in the 1958– 1988 time series, but not since 1979.”
Oh my! The coincidences!
I refer you to my submission to the ‘Climategate’ Inquiry (i.e. whitewash) by the UK Select Committee which was also in 2009. It is recorded in Hansard (i.e. the official record of the UK Parliament’s business) here https://publications.parliament.uk/pa/cm200910/cmselect/cmsctech/387b/387we02.htm
The submission concerns one of the emails from me which were among those leaked from the Climate Research Unit (CRU) of East Anglia University (UEA): that email was from 2003 and is part of my complaints at the nefarious method being used to block publication of my paper which explained need to revise methods for determination of mean global temperature (MGT).
My submission to the Inquiry explained the nefarious method used to block the and provided a draft (as Appendix B) of the blocked paper.
As Appendix B of the Submission shows, the blocked paper also mentions 1979 when it says,
“The data sets keep changing for unknown (and unpublished) reasons although there is no obvious reason to change a datum for MGT that is for decades in the past. It seems that—in the absence of any possibility of calibration—the compilers of the data sets adjust their data in attempts to agree with each other. Furthermore, they seem to adjust their recent data (ie since 1979) to agree with the truly global measurements of MGT obtained using measurements obtained using microwave sounding units (MSU) mounted on orbital satelites since 1979. This adjustment to agree with the MSU data may contribute to the fact that the Jones et al., GISS and GHCN data sets each show no statistically significant rise in MGT since 1995 (ie for the last 15 years). However, the Jones et al., GISS and GHCN data sets keep lowering their MGT values for temperatures decades ago.”
Richard

77. Until a few years ago, the kilogram was defined as the mass of a platinum-iridium object stored in the International Bureau of Weights and Measures in Paris. It has been found that its mass changes over time by something like 0.000005% per century

nope. its Mass is the same.
its the standard it cant change, or rather you cant find an independent way to measure it.

78. However, we have to look at the bare facts, regardless how impossible they seem.

bare facts? THERE ARE NO BARE FACTS.

FACTS ONLY APPEAR IN A THEORETICAL SETTING.

Here is what we know.

we know CO2 cause a rise in temperature.

• Agnostic

Yes, but the causality is the wrong way if CO2 was a forcing. CO2 and its radiative effects should be treated as a positive feedback.

Warming causes processes that breakdown organic matter to speed up which releases more CO2 than normal from a vast and virtually endless reservoir, which causes more warming etc etc.