by Judith Curry
The original thread for Andy Lacis’ post got derailed by non-technical comments. This thread is STRICTLY for technical comments (heavy moderation will be imposed); make your general comments on the original thread.
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Just because you don’t explicitly assume something doesn’t mean that you haven’t implictly assumed it in the parameterisation of your models. It’s very hard to avoid implict assumptions in any complex model.
But if your chosen parameters trace back to measured data, that trap is sprung. Where GCMs parameterize, the parameterization is based on observation. OTOH, if you think fluid dynamics, radiative transfer, diurnal variation and a non-flat Earth are parameterization, well, you might have a point.
We have a data-set that would allow the sensitivity, in the absence of water vapour, to be calculated.
If CO2 does, of itself, increase the recycling of outgoing long wave radiation than its signature should be obvious.
We have the temperature data-sets from the Antarctic bases from the 60’s until now. If CO2 is a potent GHG than we will see an increase in the RATE at which it warms following the onset of polar summer and a decrease in the RATE at which it cools on the onset of winter.
We could compare the average 1970-1980 rates with the 2000-2010 rates. If CO2 recycling occurs, it would stand out like a sore thumb.
Even a Hare-Brained physicist would have to agree that CO2 cannot change its behavior just because it is sitting above one of the poles.
So, either the hypothesis is testable, based on a clean data-set, or it isn’t.
But do they want the hypothesis tested?
This won’t work because the warming effect of CO2 is greater at night (=winter for Antarctica) than during the day (=summer for Antarctica), which reduces the diurnal (=seasonal) range, and therefore lowers the rate of change. One would probably have to resort to modeling to determine which effect is larger &:>)
That said, I downloaded the monthly data for Vostok – http://south.aari.nw.ru/data/data.asp?lang=0&station=6 – and compared the T difference of Jan – Apr (onset of winter) and Sep – Dec (onset of summer) for 2000-2010 averages and 1958-1967; the cooling was slightly faster, -0.2 degrees Jan-April, in the earlier period 1958-1967. Warming was much faster, 1.11 degrees Sep-Dec, on average, in 2000-2010. Sorta confirms your hypothesis.
Eli,
See my comments below (or not). Fluid dynamics in GCMs is parameterized – yes? – in the sense that the processes that occur, e.g. convective cells, are at sub-model scale. If so, what is an example of how such a parameterization is arrived at, and validated?
Bill
Josh Halpern, the parameters in GCMS are indeed partially based on observation, but many of them are not in any meaningful sense determined by observation. If they were then there would be (near) universal agreement on their values. The enormous variability seen in GCMs (and remember that we only see in public the results from the subset which are not obviously hopelessly wrong) shows how little we really know about how to parameterise them.
At best the current situation can be described as educated guesswork, and poorly educated guesswork at that. Trying to deduce anything important from their output is a mug’s game.
The shallow water simplification of the Navier-Stokes equations is the basis for atmospheric fluid-dynamic models, the dynamic core, in some ( most? ) GCMs. The momentum balance in the vertical, or radial, direction is simplified to state the hydro-static balance condition and thus carries no geometric requirements: flat plate or sphere, it doesn’t care. The momentum-diffusion terms in the remaining equations in these models are grid-scale dependent: a parameterization. Some models even include what have been called momentum-dissipation terms: no such terms are present in the fundamental Navier-Stokes equations. Another parameterization. The detailed topology of the Earth’s surface cannot be resolved at the presently used grid-scale resolution. Significant surface topology must be parameterized. Even today, some GCMs do not yet employ coordinate transformations to account for the varying topology of the Earth’s surface. In a spherical coordinate system, many terms can be shown to be important as the ratio of the radial extent of the representation of the atmosphere to the radius of the Earth. A very small value, and these terms are frequently dropped. I call setting terms to zero as a parameterization for those terms. For applications to rotating systems it is critical to include the important Coriolis terms. The Coriolis terms can be correctly represented in any coordinate system: spherical or not. All radiative energy transport calculations of real-world Earth applications will include parameterizations if there is present in the atmosphere stuff other than homogeneous gaseous mixtures. I think that requirement means that every calculation will involve parameterizations. The diurnal variation is an output that is a function of all these parameterizations, plus many others.
‘The detailed topology of the Earth’s surface cannot be resolved at the presently used grid-scale resolution”
Are you joking?
Surely all the temperature readings are converted to sea level?
If not then the lapse rate make a mockery of the whole thing.
Co2 as a knob on the control board makes prefect sense. The radiative impact of CO2 increases as water vapor decreases and decreases as water vapor increases. The concentrations of each as absorptive gases dampens the impact of the other. They are not perfectly adjusted, as water vapor has a different delay due to transport from the low latitudes to the higher latitudes.
Pretty amazing relationship.
Funny you should say that, because the way I understood it, the main point of Lacis’ article is precisely that water vapour / condensing GHGs are *not* “control knobs”, whereas CO2 / non-condensing GHGs are (in the sense that if you alter the former, you end up with a similar result, whereas if you alter the latter, you really do change long-term status).
In the atmosphere, as in life, no thing is only one thing.
1.) CO2 has a role in setting a baseline GHG effect.
Where humidity drops to zero, CO2 and the other noncondensers are still there, chugging along, absorbing and backradiating, getting all warm and fuzzy, keeping the surface temperature higher than it would have been otherwise, in that steep portion of the logarithmic curve of relationship between concentration and absorbtivity.
Naturally, the noncondenser set do not cover the entire spectrum abandoned by that rascally H2O molecule when it condenses below the absorbtivity threshold of the noncondensers, but the more noncondensers there are, the higher that baseline temperature becomes.
This thickening of the floor ought alter dynamics that had depended on the earlier, thinner floor. Thermomechanical relationships are sensitive to loss of cold range. How the complexities of climate are affected, probably impossible to say in detail. Except we know there must be some effect.
In this way, the fulcrum of atmospheric heating is moved toward the hot side, or the lever is limited in the downwards direction, or if we are keeping to the control knob analogy, someone has drilled a screw into the control panel to prevent the knob from being turned down to its old off position.
2.) CO2 has a control knob effect like a transistor, too. A small, persistent heating increase promotes water vapor levels to rise and preserves water as vapor longer when it might otherwise condense to form clouds or precipitation. Both of those effects in turn lead to higher water vapor greenhouse effect (some 20x CO2’s effect at some concentration ratios).
3.) CO2 makes most planted areas much more efficient at water vapor transport in the long run during a season, due promoting size of plants and vigor of soil microbes. While this has unpredictable effects overall on the botany, on the atmosphere there is an increase both in variability of aerosols due increase variability of plant activity, and higher overall water vapor in the air. There may also be an albedo effect.
4.) CO2 has much more unpredictable and difficult-to-correlate higher-order effects as a control knob via ocean life and ocean stoichiometry. This is likely to mean higher variability, which would likely mean higher net water vapor heating some of the time. Call this effect an out-of-control-knob.
5.) CO2 works differently above and below the tropopause in some ways, not so much due its own action as for example due the dropping out of the action of convection in the high atmosphere, the differences in condensing GHGs, and so forth.. and as CO2 levels change, the height of the tropopause and indeed the height of the solar tide shift, too.
Sure, these are generally small, incremental, or even negligible effects in any day, or decade. Possibly, they don’t matter in a millennium, some of them.
But then, we’re very far from having enough data to disconfirm them, and the best data we do have suggests several or all of these effects are significant, cumulative over time and growing.
There are four major points from the Lacis et al., 2010 paper which stand out.
1) The use of the term ‘equilibrium’ as a description of temperature, and if the uses of a global averaging of max/min temperature is a reasonable index for measuring the heat in the Earth system.
2) The use of the terms ‘feedback’ and ‘forcing’. Neither of these terms is formally defined in Lacis et al., 2010, nor is their strict thermodynamic/kinetic meaning absolutely defined.
3) Lacis et al., clearly state, that noncondensing greenhouse gases, especially CO2, drag the whole climate. Without CO2, there is a negative-feedback at work that plunges the Earth into a minus 22 degree, ice ball Earth state.
4) Thus, Lacis et al., believe that the Earth’s temperature is in a metastable position; this leads to one of two outcome:-
A) should CO2 levels fall, then we have runaway cooling; a sudden fertilization of the oceans with metals and phosphates would do this.
Should an exterior event occur which drops the Earths temperature, like the Earths passage through a stellar gas/dust cloud, then the Earth will cool.
Cool oceans will absorb atmospheric CO2, then the heat trapped by CO2 will decline, causing further cooling. Next, ice will form and change the albedo, bouncing energy off into space and further cooling the Earth. As CO2 is responsible for the amount of water vapour, we will have increased desertification and loss of water into the land ecosystems. Animal life, especially large herbivorous grass and tree cutters, go into terminal decline. Then do the plants, cold and low CO2 do for them. The freezing of the peat bogs and marshes, along with the chilling of the soil surface stops CO2/CH4 recycling.
B) should CO2 levels rise, then we have runaway heating; a sudden Carbon/Sulphur rich meteorite strike of the ocean would do this.
Should an exterior event occur which increases the Earths temperature, like Yellow Stone super-vulcano eruption, then the Earth will warm.
Warming oceans will increase atmospheric CO2, then the heat trapped by CO2 will increase, increasing water vapour and still further heating. Next, ice will melt and change the albedo, bouncing energy downward and further heating the Earth. As CO2/water vapour increases, we will flood the land ecosystems, especially all the rain forests, with 5 mm’s of topsoil. The heating of the peat bogs and marshes, along with the heating of the soil surface causes a massive release of CO2/CH4. Rising sea levels salinate all the large rivers and poison fresh water habitats in land. We generate bogs and marshes from forests and savanna; again increasing CO2 and methane.
The Earth heats up until life collapses and all the organic matter is converted into CO2. Heat death of the planet.
The temperature sensitivety of a CO2 driven Earth is too high to allow life to emerge. It is not possible for the Earth to survive periodic bombardments or massive volcanoes without dying.
In steady state analysis, as opposed to equilibrium analysis, you can as a rule of thumb state: “any steady state system I observe is inherently stable”. Stable systems are notable for the presence of negative feedback’s.
A non-stable system does not survive long enough to be observed.
If the Earth was akin the spinning spinning plate on the circus magicians cane, then the clowns would have knocked it over by now.
Yet the sensitivity to CO2 is logarithmic.
‘Yet the sensitivity to CO2 is logarithmic’
Why?
The absorbance of photons by CO2 will be logarithmic. The amount of water vapour in the air is pretty much exponential. As, we are informed, CO2 drives water vapour and water vapour is the main GHG,
Why should the [CO2]*[H2O] sum be logarithmic?
Fortunately [H2O] hits a ceiling where it condenses into droplets.
In reality or in the models?
“Thus, Lacis et al., believe that the Earth’s temperature is in a metastable position; this leads to one of two outcome….should CO2 levels rise, then we have runaway heating…The Earth heats up until life collapses and all the organic matter is converted into CO2. Heat death of the planet”
I really don’t think Lacis et al. do believe that. The very model they used in their study doesn’t show such an outcome if CO2 levels rise.
Would it be possible for Andy Lacis’ to advise as to his general opinion on the technical merits of current climate models versus the control system analysis approach he appears to be advocating? Stated somewhat differently, does he have some form of tentative assessment as to which may be a more solid approach?
I must confess that after reading the post I was left scratching my head wondering as to what he is ultimately driving at. Are the current models inherently not appropriate or too weak?
On the Control Theory thread I said, w/r/t Lacis, “the degree of confidence seems to be reasonable w/r/t the basic radiative transfer equations and too high with respect to other variables. I think the problems are generally twofold: 1) getting the parameters right for the necessary paramaterizations of physical processes occurring at scales below the model resolution and 2) the inclusion or neglect of important variables such as the biosphere, ocean dynamics etc.”
I think it would be good to have extensive comment on #1 above.
Clarification attempt #1, though what I’m asking may be silly, if so, please point it out:
We have discussed ad nauseam on this blog the radiative transfer functions, and we have had ad nauseam hand waving about the other processes of heat transfer in the atmosphere.
Can we have a technical discussion about how the latter is parameterized in the models?
Non technical, but will Andy Lacis be joining people in the comments..
As only by discussion with the author will points be resolved.
I think the very first question by Professor Jonathan Jones is very apt?
It’s apt but rhetorical in the sense that we blog participants can’t know the answer without taking apart the models.
Almost true, but not quite. We can deduce something about the models from the fact that their outputs are so variable, even after they have been culled to remove the obviously wrong ones. In essence we can deduce that the underlying problem is not well understood.
Good point. Though I don’t know that I agree with the last sentence. “not well understood” is a value judgment related to your purpose for creating/using the models. We have people arguing back and forth here & elsewhere about whether the models are adequately predicting the present. Again, adequately is a value judgment and not only that, it’s a time snapshot of a value judgment. All other things equal (hah!) if we don’t see any more warming through 2020, there will be more people than now arguing for inadequacy.
I agree, if models diverge, the interesting thing is why they diverge because this is, crudely, a parameter sensitivity.
So, what is the consensus conclusion to be now? As CO2 goes up so does the temperature until the point that it doesn’t go up at which point the temperature goes down? In other words, nothing matters except for human CO2 because of its mystical properties ascribed to it that have yet to be observed in nature?
Is CO2 slipped the bonds of science to become Major Tom to Ground Control and, as Willis wryly observes, “everything else just averages out in the long run… GHGs rule, OK?”
As Willis observes, it is a hypothesis that, “is woefully short of either theoretical or observational support. In part, of course, this is because the AGW hypothesis provides almost nothing in the way of a statement or a prediction which can be falsified. This difficulty in falsification of the hypothesis, while perhaps attractive to the proponents of the hypothesis, inevitably implies a corresponding difficulty in verification or support of the hypothesis.
“In addition, a number of arguably cogent and certainly feasible scientific objections have been raised against various parts of the hypothesis, from the nature and sign of the forcings considered and unconsidered, to the existence of natural thermostatic mechanisms.”
Lacis, et al., serves only to correct the IPCC’s preemptive consensus conclusion that, “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level…” As Willis observed in his open letter to Dr. Trenberth, looking now to human CO2 as being a thumb of greatest importance on the global thermostat is nothing more than, “Unequivocal Equivocation.”
Lacis says this:
More specifically: (1) precise measurements show atmospheric CO2 has increased from its 280 ppm pre-industrial value to the current ~390 ppm; (2) there is available an accurate HITRAN tabulation of line absorption coefficients for all of the atmospheric absorbing gases; (3) we have available accurate radiation modeling techniques as well as capable global climate models; and (4) that 9 Gigatons of carbon (coal, gas, oil) are being burned each year (by us humans).
#1, #2, #4 -> stipulate for purposes of this discussion.
#3 – stipulate part a (accurate radiation modeling techniques) and stipulate incorporation of such into GCMs.
which leaves us with:
#3 – part b, capable (balance of) GCMs.
My sense of the control theory approach (per Saumarez) is that the assumptions of adequate linearization etc. would be validated by 1) more data, yes, that would be great and 2) excellence in GCModeling.
It’s one thing to claim that excellence. It’s another thing to show it. I’m not saying it doesn’t exist, I don’t know.
I’d appreciate summaries of where participants stood on the technical issues in the previous post. It seemed that some considered Lacis’s science pretty solid but others took strong exception.
For myself, I consider CO2 as a GHG warming the planet a solid proposition. I question whether it is the “principle control knob” as Lacis puts it and whether climate science can even know that as yet, as well answering the precise questions of how much anthro carbon will warm the planet and how fast. However, I am not a climate scientist and am not as well-versed as many here.
Hux,
I am not a climate scientist. I am a civil engineer. I think that parts of Lacis’ science are pretty solid, and they are some of the same parts as discussed previously herein via reference to Pierrehumbert, etc. Lacis’ posts that were linked to Roger Pielke SR’s blog, which were better on data. I don’t think we know enough yet to fully support the control knob idea in the sense that he puts it forth. I think that the juxtaposition of Lacis and Saumarez here is interesting, in that the whole Spencer/Dessler/fast feedbacks/”what can we do with the data we have?” issue may or may not be a distraction.
See my “stipulations” above and question to Eli Rabett.
Bill
Thanks for this good summary. Will you kindly consider addressing a few additional related issues.
Because all the action occurs on spatial scales that are less than the resolved scales, none of the important physical phenomena and processes related to clouds are treated from first principles. These include the vertical motions of clouds, all the radiative-energy-transport characterizations of the non-vaporous ( gaseous ) phases of water in the clouds, the vertical locations of the cloud tops, the distributions of the non-vaporous phases of water within the clouds, and all aspects of precipitation of liquid- and solid-phase water from the clouds. There are very likely many others. Discussions of the accuracy of radiative-energy transport in the presence of the vaporous phase of water is all well and good, but is that the dominate physical phenomena of interest when clouds are the focus?
How can we be assured that these parameterizations have not introduced phenomena and processes that are not in accord with the real-world systems of interest. For example, have sensitivity investigations of the effects of uncertainties in the parameterizations been conducted so as to show that these are not important to the conclusions of the papers cited in your post.
Almost all models of the important physical phenomena and processes involve, to greater and lesser degrees, parameterizations. Some are based on fitting of empirical data while others are ad hoc ( for this case only ). What are the dominate parameterizations for the control-knob analyses and has the sensitivity of the results to changes in these parameterizations been determined.
Conservation of energy. Some GCM numerical solution methods do not conserve energy ( or mass ) but instead include use of energy ( and mass ) fixers to attempt to conserve energy ( and mass ). Is there information available to show that the magnitude of these ad hoc conservation fixers are sufficiently small so as to not affect the results of the papers cited in your post. What is the magnitude of the corrections compared to that of the signal of interest?
The physical system of interest is not now and has never been in equilibrium. What is the estimated time scale necessary to ensure that the periods when there is an excess of net energy loss from the system is balanced by those for which there is an excess of net energy input into the system. Are the GCM calculations of the radiative-energy budget at the TOA in accord with measured data?
Thanks
Dan – I think you raise important questions that a climate modeler (Lacis, Held, Schmidt, Hansen, etc.) would be qualified to answer but those of us who don’t create GCMs would not. Perhaps Andy can be persuaded to visit and respond. Obviously, the validity of parametrizations is a critical issue that requires constant checking against empirical data to the extent possible,
I found his post yesterday to be intriguing. There was little scientific documentation in the post itself, but the Science and GRL papers are useful for that purpose. Andy is quite correct in the general principles he described regarding greenhouse gas warming and the relative contributions of CO2 and water (approximately), and my own questions related primarily to apportionment between anthropogenic forcing and natural unforced variability,which can be considerable on short timescales but probably less so averaged over the six decades since 1950- a notion I’ve advanced previously.
The meaning of “equilibrium” has been questioned in this thread and elsewhere, but this perhaps involves a misunderstanding of multiple uses of the term. In general, climate equilibrium relates to a radiative balance at the top of the atmosphere between incoming and outgoing radiant energy on a global average, and is not intended to imply balances at all locations. It must have occurred transiently on many past occasions when the climate moved between positive and negative imbalances, but during any given interval, it is considered only approximately the case when imbalances are small, and to be a non-equilibrium circumstance when the imbalances are substantial and associated with significant global temperature trends.
This is Radiative Equilibrium, and is not intended to be the same as thermodynamic equilibrium. The latter is never likely to prevail on any large scale but is a useful concept – “local thermodynamic equilibrium” or LTE – in calculations of atmospheric phenomena within very small distances.
Fred,
I meant to say, The physical system of interest is not now and has never been in radiative-energy transport equilibrium. Internally, of course, it’s all non-equilibrium, all the time: otherwise nothing would be happening. My question at the end was meant to address specifically this issue. And I seldom, if ever, address non-equilibrium thermodynamics, only thermodynamic non-equilibrium within the context of equilibrium thermodynamics.
Let me attempt to put the general issues into the framework of Professor Curry’s recent work. All calculations using GCMs will involve parameterizations. Each focus area ( system response ) will have some of these to be much more important than others. There will be a few, and we hope it is a very small number, that are critically important. And some of these might be more ad hoc-ish than others. It would be important, I think, to investigate the effects of varying the critically important parameterizations over the ranges of uncertainties associated with each. Quantify the effects of the uncertainty.
Dan, your second paragraph triggered a thought. I apologize to all if it’s been answered many times over elsewhere.
To what extent have sensitivity analyses been conducted on the GCMs, meaning, do we know which parameters of the models create the largest swings in the output? And, of those swings, how many of them cooling versus warming?
“It would be important, I think, to investigate the effects of varying the critically important parameterizations over the ranges of uncertainties associated with each.”
This is of course being done. This page of the AR4 and the following ones gives a summary.
That summary is pretty sparse. Testing the bits and pieces is necessary. What isn’t mentioned is how much testing of the interactions among the various paramaterized functions and numerical solutions used to estimate various partial differential equations. This is the kind of verification and validation that should be ongoing by independent organziations.
“In general, climate equilibrium relates to a radiative balance at the top of the atmosphere between incoming and outgoing radiant energy on a global average, and is not intended to imply balances at all locations”
I am sure what you mean by ‘on a global average’.
At steady state efflux = influx. So far so good.
We can sum all annual solar influx and sum all the radiative efflux over the same time and they will be equal, unless work is being done.
We can have a global balance of influx/efflux over a decadal time span and still have a huge difference in the ‘average’ global temperature as measured by Tmax+Tmin/2 gridded across the planet.
My I be God for a moment, or some other supernatural deity with none thermodynamically limitations.
As God I sudden take an interest in cloud sculpting. I want to move them around. When I place clouds above poles I warm the planet, and yet have no impact on the radiative efflux. After a decade of falling global temperatures I get bored and place my clouds over the forests. Placing my clouds here heats the planet, again without changing the radiative efflux.
Clouds with an average albedo of 0.8 cover 50% of the planet. Placing them over snow or areas with a high albedo, cools the planet; as I unmask areas with very low albedo’s.
To do a really good trick I could modulate the ocean currents to have a rhythm that alters the location of clouds on a global scale. An El nina stops clouds poping into Central Texas from the Gulf and raining on the desert/scrub-land. So the albedo changes from 0.3, scrub-land, to 0.45, desert. So I heat Texas. However, my clouds are stuck out in the Gulf, cooling it.
Nothing new here…”yes, we know that CO2 is a greenhouse gas. And we know it will increase the forcing, although the amount is not well established. But we absolutely do not know if that will cause the earth to warm over time.” ~Willis Eschenbach (pointing to the obvious example that solar radiation warms what it hits: “If your house has an air conditioner on a thermostat, despite the sun getting warmer and warmer as the day goes on, the house does not warm up. Again, we have a radiation source which does not cause what it strikes to warm up.”
“we absolutely do not know”
Know as in 100%? no. But we know to a high degree. It’s highly unlikely that a CO2 specific thermostat exists in climate. It’s a real stretch.
The LIA proves that temperature can go down with no change in CO2.
The MWP proves temperature can go up with no change in CO2.
Albedo, bright sunshine and UV changes over the 20th century probably controlled temperature.
Until someone can point to a period where the only climate factor that changed was CO2 and the temperature went up, then CO2’s effect on temperature is a mystery.
“The LIA proves that temperature can go down with no change in CO2.”
It also proves that there’s no generic thermostat in climate preventing that kind of temperature change.
We therefore require a CO2-specific thermostat – something that is far more specific and rather implausible.
“Until someone can point to a period where the only climate factor that changed was CO2 and the temperature went up, then CO2′s effect on temperature is a mystery.”
Not at all. The induced imbalance is 3.7wm-2 when CO2 doubles. You need a very strong thermostat to stop that producing any warming.
So:
A generic thermostat: disproved by LIA and MWP
A CO2-specific thermostat: rather implausible
A very strong CO2-specific thermostat: you have to be kidding me
Until the past behavior of CO2 in the climate as a lagging reaction to temperatures whose increase did not act to increase temperature is explained, claiming that CO2 is a control knob/thermostat is unsupportable.
hypothesis: mutual positive feedbacks with diminishing returns.
increase CO2, get warming, more CO2 comes out, little more warming, little more CO2, tiny bit more warming
warm earth, more CO2 comes out, little more warming, little more CO2, tiny bit more warming
There! Done!
Bill,
Is that what the agreed on record shows?
No.
hunter-
you mean the CO2 in the record continues to increase after temps have begun to cool?
i’d take that as a refutation. hypothesis rejected, on to the next one :)
Bill
Bill C:
Hypothesis: all temperature variability observed since is NOT outside the bounds of historical, natural variation.
WFGW,
Taht would be a null hypothesis of some usefulness, imho.
Although steve mosher does not agree with that opinion.
I agree with Steven Mosher. The historical bounds of natural variation are far too wide for them to be a useful metric for anything, especially as the world was a very different place in the past to how it is now. Secondly, the historical variations in CO2 levels as a response to other forcings are part of historical natural variation so can’t by definition be outside it. Finally, if you are referring to climate change as a response to man made CO2 emissions it doesn’t logically follow that such climate change would have to fall outside historical natural bounds in order for AGW to be a real and potentially serious phenomenon.
Sorry non-technical so delete away, but the “control knob” metaphor strikes me as so profoundly simplistic that I can’t help thinking it was designed as a sales tool to convince the mostly scientifically illiterate public.
Control knobs + hockey sticks = global warming for dummies.
An imaginary control knob is needed if you are to imagine the Earth getting hotter with no change or effect from a change in solar radiation.
On the original thread I posted three things that Andy said which, I believe, are just plain wrong. That is, there is no sound physics to support them. These are
“The greenhouse physics, (and the increase of atmospheric greenhouse gases) as the fundamental basis for global warming, are well founded. (My brackets)
Solar forcing is cyclical and small, while the GHG residence time is very long.
Fortunately, the global warming component, it being tied directly to the growing strength of the terrestrial greenhouse effect, is a uniquely radiative effect that can be addressed independently of the other climate complexities”
The one I object to most strongly is the last. I know of no physics that allows anyone to conclude that one can assess, quantitatively, the effect of adding more CO2 to the atmosphere from current levels, that allows the complete neglect of the other ways is which energy is trensferred through the atmosphere. There is simply no proof that Andy’s statement is correct.
I suspect if people reread Andy’s paper you see that it’s not very controversial.
“t often is stated that water vapor is the chief
greenhouse gas (GHG) in the atmosphere.
For example, it has been asserted that “about
98% of the natural greenhouse effect is due to
water vapour and stratiform clouds with CO2
contributing less than 2%” (1). If true, this would
imply that changes in atmospheric CO2 are not
important influences on the natural greenhouse
capacity of Earth, and that the continuing increase in CO2 due to human activity is therefore
not relevant to climate change. This misunderstanding is resolved through simple examination
of the terrestrial greenhouse”
That tells you the sum total of everything you need to know.
Andy and Gavin use a GCM to examine a very simple question and answer a very common misunderstanding. They use the only tool available to investigate such a question. Here is what they found.
If you drop C02 to zero, you get a frickin cold planet. It may well be that C02 adds only a fraction of the total GHG effect, but without that non condensible gas in the atmosphere, you have a ice planet. Its a forcing.
Conversely, if you drop all the water vapor out of the atmosphere, it replaces itself within a couple weeks. its a feedback.
Brutally simple. Brilliant. But the bottom line is that it merely addresses a mistaken argument made by skeptics. So, personally I would not have given it an award. Further it does not address the most important question.
what is the gain on that control knob?
Facts are facts. If you remove every last bit of CO2 from a greenhouse it will still get hot inside the greenhouse. And, if you pump CO2 into a greenhouse you will not get runaway warming. The whole notion of a ‘greenhouse’ to explain climate is a fiction.
Yes, because a physical greenhouse is typically built out of glass. Radiation comes in and the heat it creates can’t convect out easily.
On the contrary, I think this outlandish result simply shows that the models are no good, probably in the same way that the runaway warming they tend to exhibit shows that they are no good. We know that the models have a net positive feedback to CO2 increases built into them, so it is no wonder that decreasing the CO2 leads to unrealistic cooling. It is the same mistake running backwards.
you call the result outlandish and describe the cooling from removing CO2, methane, etc “unrealistic”, both implying that you expect a completely different result. What result did you expect and what is that expectation based on?
I build a model of a chemical reaction. It is based on a parameterized model of the reaction from basic observations in laboratory glassware. It involves all sorts of partial differential equations.
In the model I increase the temperature of the reactor and my reaction yields a high level of Chemical A. I decrease the temperature and the reaction yields no Chemical A.
When I run the reaction in a reactor, indeed if the temperature is too low, I get no A. But when I turn the temperature up, I also get no A. Instead, I get B. Why? Because something I didn’t know – namely that a secondary reaction would happen that didn’t in the glassware – happens as well. So much for my model’s competency.
This is a true story and frankly not a very complicated situation.
What are the odds there is something that will happen in the climate system that I haven’t accounted for in my GCM?
Wis, I actually had that problem with a Grignard reaction.
I could not scale up, either in volume or X-MgBr concentration. I could get quite good yields at low volumes and low concentrations, but not at 10x of either. Drove me nuts.
wrong. Its the very kind of test you would do to make sure the models give reasonable results.
But the problem is that we don’t know how our present atmosphere would react to the removal of all CO2 in its current form. It might freeze up, or it might not due to the ongoing dynamics all the other greenhouse effects.
So it’s not at all certain if the model’s result is “reasonable”. Certainly the model produces this result in its current form, but this could just reflect the fact that the dependence on CO2 is built into the model’s assumptions while the real earth behaves quite differently.
Steven: you write: “It may well be that C02 adds only a fraction of the total GHG effect, but without that non condensible gas in the atmosphere, you have a ice planet. Its a forcing. Conversely, if you drop all the water vapor out of the atmosphere, it replaces itself within a couple weeks. its a feedback.” I seem to be missing something here. I would have thought that if all the CO2 was removed from the atmosphere it would promptly, just like H2O although more slowly, be replenished to present levels from the reservoir stored in the oceans. Does that make it also a feedback? What have I missed? Is it just the greater time lag with CO2?
@Steve Mosher
What happens if CO2 drops to 100 ppm? Does the model predict the death of all life on the planet and the impact of that on the climate?
Off topic. Go get a GCM, read the code, get back to me. Giss ModelE is only 100K Loc. Didnt take me long, but I’m not doing your homework
Thanks, appreciate your help. Your grace and helpfulness are unbounded.
ps – perhaps the questions might have been rhetorical by the way.
Which is why I found the paper banal. Aren’t they trying to thrash a straw man argument by going after this water vapor forcing thing in the scientific literature? I know Spencer said something strange about clouds being a forcing, but I don’t think he was saying that water vapor itself was a forcing. Who is Lacis arguing with?
Yes, banal. I would have expected people to do this kind of test to test the model in the first place. weird.
Steven, Are you sure that is the issue with the models? I was think most of the difference was the assumption of water vapor in the tropopause lower strat instead of ice crystal which have a little clearer radiation window. It only takes about 20Wm-2, there to explain things. That’s the water vapor control knob as I see it, and Solomon et al.
I think the first paragraph says it all. he is arguing with the silly argument that some skeptics make. The issue is this, people silly enough to make the initial argument WONT GET the paper.
That was what I was thinking. But more to the point, what is the point of this in the scientific literature? I think that a lot of “consensus” types expend a huge amount of energy beating down straw men, because they can’t tell the difference between a serious argument and a naive one. The whole thing is out of control. They probably do believe that serious skeptics don’t understand that water condenses. And that’s their own fault for not engaging the skeptics, but instead trying to fire these kinds of strawballs from their citadel.
so whose fault is it that loads of stupid skeptics still go around claiming water vapor is 95% of the greenhouse effect?
I just realized I said it was both brilliant and banal. somehow I think thats strangely true. I think it would be good in a textbook to get a point across, but it’s not a great scientific paper. Even as a counter to skeptic arguments it relies on something ( models) that they refuse to understand.
@steven mosher
Sceptics don’t ‘refuse to understand’ models.
Au contraire, mon brave, we understand them all too well. And we take away two key points:
1. They have zero demonstrable predictive skill – speaks to technical capability of the modelling
2. The ‘modelling community’ do not view this fundamental failing as anything to be concerned about – speaks to objectives of the modelling process.
So we have a modelling process that does no consider predictive skill to be important – and a technical implementation that reflects that lack of priority.
Either of these alone would casue me to be deeply suspicious of any modelled output. The combination is terminal to its credibility. If a model cannot make accurate predictions then it is of little value at all
Would you follow a racing tipster who never got a winner and also made it abundantly clear that they didn’t view this as a problem?
Your argument ‘models are the best we have’ is frankly pathetic in the light of the above.
If I have missed somethign fundamental about models here, please put me right. Thanks
But the bottom line is that it merely addresses a mistaken argument made by skeptics.
It is only mistaken if the models are correct. I do believe that they are correct enough: probably without CO2 the H2O would mostly precipitate out and the Earth would cool.
Further it does not address the most important question.
which is “What happens next?” You can not even know (though you might assume it) that the gain is constant independent of temperature.
I expect that, by next year at this time, there will be 5 peer-reviewed publications showing that the effect of adding CO2 to the atmosphere as it is today, at the temperatures we have today, will be to reduce the spatio-temporally averaged Earth surface temperature.
“If you drop C02 to zero, you get a frickin cold planet. ”
You can’t drop CO2 to zero. It near zero at the moment though you get it closer to zero, but you nor mother nature can make it zero.
And we have had a frickin cold planet- having a frickin cold planet has been the norm for last 50 million years.
“Conversely, if you drop all the water vapor out of the atmosphere, it replaces itself within a couple weeks. its a feedback.”
Conversely if halved or quartered the amount CO2 in the atmosphere, the ocean would emit it- it’s feedback.
also there isn’t a way to drop all water vapor out of the atmosphere.
If you took the entire atmosphere and liquified- thereby separating out almost all of the water- it still has the impurity of water in the cryogenic form.
On a clear cloudless day, anywhere on earth, there more water vapor in the air than CO2. And you can’t get water down to 400 ppm level- without
doing something like liquidify the air- somehow bringing the air down below -150 C.
precisely, that is WHY they have to use a GCM to do this. there is no way to slam an asteroid into the planet, but we can build physics based simulations to play what if games. these are not experiments, but they are the best estimate we have
I’m a bit confused by your response. gbaikie’s point is that it’s impossible for all the water vapor to drop out of the atmosphere even if it’s quite icy. You’re agreeing with that point.
So if the model is predicting that the water vapor disappears, when in fact we think that is actually impossible, then the model has gotten something fundamentally incorrect about atmospheric chemistry.
This seems contradictory, what am I missing here?
Asteroids hitting the planet have occurred and can occur, CO2 less than 150 ppm can’t occur.
Sounds like it is a bunch of fun too. What does it cost us all to play? A hole bunch we bet.
“So if the model is predicting that the water vapor disappears, when in fact we think that is actually impossible, then the model has gotten something fundamentally incorrect about atmospheric chemistry.
This seems contradictory, what am I missing here?”
The model isn’t predicting that water vapor disappears
Look at the GCM run they did. We are talking about a GCM “experiment”.
And yes, you can drop it to zero. you can double it, you can input whatever the hell you like.
The question is, are the physics and modelling reliable enough to draw a conclusion about the question: How important is C02 ?
If fantasy role playing is also an “experiment”.
Planets with atmospheres in this universe do not have 400 ppm or less of CO in them, unless they have life.
With the exception being if they massive amounts of hydrogen or Helium which diluting any CO2 or the Planet is as cold or colder than Mars making CO2 gas freeze into a solid.
Any planet with less than 150 ppm has plants unlike any on Earth or some mechanism which allows the plants getting a higher concentration.
Or it’s inhabited psychotic intelligent life.
Running a model at the extremes of the input variables (even if we wouldn’t normally see those) is done all the time. If you get ridiculous results, then you have a model problem. A simple check, easy and frequently done in the modeling world.
“what is the gain on that control knob?”
I would change that to what is the range of the gain on that control knob, and what is the nature of its response within that range? A point well made none the less.
I have a technical question. Lacis seems very confident in his estimates of sensitivity to CO2. It does seem to be based on models. Is there any scientific basis for this given the wide differences between the GCM sensitivities? It seems obvious to me that model results must be rather sensitive to the subgrid models of clouds and aerosols. Yet the IPPC says scientific understanding of these is low.
Judy, what am I missing here?
David, you are asking what, to me, is the key question. There is no observed data which measures climate sensitivity. Or rather, such crude estimates that one can make from observed datas indicates that the CO2 “signal” for producing global warming is negligible. All the values for climate sensitivity, quoted by the proponents of CAGW, are based on non-validated models, and as such are not worth the powder to blow them to hell. There is no way, with proper physics, to translate a change in radiative balance of the atmosphere, as one adds CO2, into a change in surface temperature. It is as simple as that.
Yes, my understanding is that they’re trying to imply the value from other factors.
Climate sensitivity too, fwiw, is an arbitrary construct and may not ACTUALLY have a (useable) value.
Personally i think it is a dynamic ‘value’ which wholly depends on the current state of the system- which would make sense in a ‘controlled*’ system.
*by controlled i’m reffering to feedbacks, both +ve and -ve
The only real contribution made by the Thermostat hypothesis — other than to account for the observation that the temperature of the globe has always been relatively stable in that it generally has been in an ice age — is to distinguish the negative feedback of cloud formation (a mechanism that global warming alarmists wanted to ignore) from the role of evaporation as a cooling mechanism.
In addition, I’ll harp on my area, numerical accuracy. The modelers Appear to have neglected to do even the easiest checks, such as do the results stay the same if the grid is refines or the time step decreased. Schmidt admits that they only that very long time simulations look reaspnable. This is “colorful fluid dynamics” leads me to assume that the numerical errors are significant, but unquantified, a very bad situation to be in for people who want to impose some radical solution, like cutting emissions 50%
“In addition, I’ll harp on my area, numerical accuracy. The modelers Appear to have neglected to do even the easiest checks, such as do the results stay the same if the grid is refines or the time step decreased.”
I think it’s wise to assume such trivial tests have been done.
See Paul Williams on this. Numerical issues are sometimes commented on, but rarely followed up. Look him up on Isaac Newton Institute and then get back to me. The problem is that modelers are always under pressure to do more model runs faster.
I agree with what you are proposing I just thought the two specific examples you gave have probably been done.
Surprisingly, these things appear to be sometimes commented on in the literature but not followed up in a systematic way. I’m telling you that I went to Real Climate as Fred Moolton suggested and the result was quite unsatisfactory. There was no response to my questions, just posturing and the assumption that the “modelers were making rational decisions.” By the way dhogaza is a complete idiot and jerk. You will see if you go there that the responses to my detailed posts were of a trivial kind. In short, 2 weeks ago I did not question the competence of the modelers. I’m now not so sure. Anything based on these models seems to me to be highly questionable and not to be believed.
By the way, I just reread the thread here on “hide the decline” and it does indeed dramatically lowers my estimation of Dr. Gavin Schmidt. Maybe he’s too young to have developed the attitude of a mature scientist. But he surely displays a juvenile character in the referenced thread. If he things climategate is not a big problem, he is dishonest. OOps, only the members of the team are fit to judge such things, I forgot that respect for authority is the engine for progress in science (just kidding).
Welcome to the club, David. Over the years, we’ve learned that one does not mention Numerical at RC.
And, welcome to Climate Etc. The climate here at Climate Etc. is much better.
Given the ultimate rationalization of the status of GCMs at RC, that is, We really don’t need them, it’s difficult to understand the response one gets over there whenever Numerical is mentioned.
David Young:
You argued that climate modelers were ignorant of the *possible* problems associated with using explicit methods to compute time step results, and ignorant of the potential benefits of using implicit methods.
If you want, I’ll cut and paste direct quotes from posts of yours from the Real Climate thread.
I pointed out that a reference that you claimed to have read yourself stated that there’s been a trend by some climate model implementation teams to move towards the use of explicit methods after having incorporated implicit methods in previous versions.
I also pointed out that this meant that your claim that climate modelers are ignorant of the potential benefits of the use of implicit methods in modeling is false.
And that it was reasonable to assume that those who move back to the use of explicit methods probably have rational reasons to do so.
You did absolutely nothing to support your claim that climate models do, in actuality, suffer from the potential problems associated with the use of explicit methods in some systems that are modeled. And were absolutely wrong in your claim that climate modelers are universally ignorant of other ways of building models and are at least two decades behind the state of the art in their understanding.
This is flat-out lie.
DY, that’s really mature of you.
Form over substance. The thread speaks for itself. Paul Williams lecture shows that there is a big need for better methods. Implicit vs explicit is just the tip of the iceberg. Do you have anything of actual technical substance to say? I mentioned several references
by the top experts in the field of numerical methods. You can read them if you want to talk about real issues. I can email them to you if you will step out from behind the anonymity that hides the lack of expertise and the posturing.
THE EMPEROR HAS NO CLOTHES!
Let us first agree on the description of the EXISTING global mean temperature (GMT) data!
Shall we?
http://bit.ly/qGcD9M
1) A straight line (not a curve with increasing positive slope with increasing years) passes through ALL the global mean temperature (GMT) peaks in the last 160 years data.
2) Another straight line passes through ALL the global mean temperature valleys in the last 160 years data.
3) These lines are parallel and are separated by 0.5 deg C and have a warming trend of 0.06 deg C per decade
4) These lines are parallel to the GMT trend of 0.06 deg C per decade for the period from the 1880s to 2000s
5) The oscillation between the upper and lower GMT boundary lines is due to thermohaline circulation cycles.
http://bit.ly/nfQr92
CONCLUSIONS
1) No change in the GMT trend of 0.06 deg C per decade since record begun 160 years ago!
2) Human emission of CO2 has no effect on the long-term GMT trend, because this trend has not changed in 160 years.
If we don’t agree on the description of the KNOWN existing data, what chance do we have in agreeing on the description of the UNKNOWN future data?
Zero!
Given that relationship the Earth was 6 degrees C cooler during the MWP than today
lolwot, you missed this: 1) No change in the GMT trend of 0.06 deg C per decade since record begun 160 years ago!
There is no “given” (except your creation) that the line extrapolates backward past the beginning of the temperature record.
there’s no given that it even covers the 160 year record.
Given that relationship the Earth was 6 degrees C cooler during the MWP than today
Have you decided that you don’t even agree with you?
@’-” Let us first agree on the description of the EXISTING global mean temperature (GMT) data!
1) No change in the GMT trend of 0.06 deg C per decade since record begun 160 years ago!”
There many possible descriptions of the existing data of which the one you suggest is not robust to small alterations.
Try changing the ‘from-to’ dates for your GMT timespan and trend to the various century long spans that can be fitted between 1880-1980 and 1910-2010.
The trend over those periods goes from ~0.04degC/decade to over 0.08degC/decade. That indicates that the first 30 years of the time series can radically alter the results.
As can the final 30 years from 1980-2010 which have a trend around double that for the last century.
Izen
If I have to repeat it a million times, I will.
1) A SINGLE LINE passes through all the GMT peaks data of the last 160 years (No need for cherry picking of start and end dates!)
2) This line has a global warming trend of 0.06 deg C per decade
3) The slope of this line is equal to the global mean temperature trend of 0.06 deg C per decade for the period from the 1880s peak to the 2000s peak
4) All the variation in the global warming trends for periods less than 120 years is due to thermohaline circulation cycles as described in the following paper
http://bit.ly/nfQr92
If I have to repeat it a million times, I will.
Girma has just described himself better than any of us could have. He is of the persuasion that the truth is that which is said the most often. This is true in politics because politics is belief-driven. It is false in science because you cannot make water dry by saying “Water is dry” a million times.
There are some who associate wilderness with danger. Girma is one of them, a political voice crying in the wilderness of science.
you still dont get why you cannot draw lines through peaks. Plus your comment is OT. wrong and off topic is no way to go through life.
steven mosher
If I am wrong, are you claiming a curve of increasing positive slope with increasing years passes through all the peaks of the global mean temperature data of the last 160 years?
http://bit.ly/qGcD9M
I believe what I see: It is a straight line that passes through all the peaks of the global mean temperature data of the last 160 years?
Steven, it is you who is off topic by commenting about my life. I have never done that!
you still dont get why you cannot draw lines through peaks. Plus your comment is OT. wrong and off topic is no way to go through life.
It’s “quantile regression”, and you can do it. For approximately equal sample sizes, the maxima estimate the same quantile. Girma’s lines show that the 95% quantile, mean, and 5% quantile all increase linearly across time at nearly the same rate. It could be done more completely, but the graphing is an integral part of the analysis.
a least squares fit does not give you the trend. google unit root and cointegration if you must. fitting a straight line tells you nothing unless you make assumptions about the underlying process
Steven claims a curve (of increasing positive slope with increasing years) passes through all the peaks of the global mean temperature data of the last 160 years?
http://bit.ly/qGcD9M
What an obfusication!
Steven
Why are the lines that pass through the GMT peaks and valley are parallel?
http://bit.ly/qGcD9M
Is it just a coincidence?
steven mosher: fitting a straight line tells you nothing unless you make assumptions about the underlying process
Fitting a straight line tells you something, it does not tell you everything. In an iterative estimation procedure, the ols fit can be used as the starting value for the iterative procedure.
“It’s “quantile regression”, and you can do it.”
Just because it can be done doesn’t mean it makes sense. PCA has already invalidated this approach – the system violates the assumptions you have to make for your technique to be applicable. CO2 has been already been conclusively shown to definitely have a role. The discussion here is how much it effects temperature through feedback..
Girma,
You are clearly incorrect.
Look at the relationship between the trend and observations as given in the Wood For Trees plot (your first link).
You should have noticed the implied behaviour of the residuals: They are the difference between the trend line and observations (subtract trend from observations). The residuals start off all positive, in the middle they’re all negative, by the end they’re all positive again.
Therefore, keeping to as simple a model as possible, the data is more accurately modelled not by a straight line but by an exponential.
The ‘science’ of global warming has become a pedagogical method and strategy and I mean that in the worst way. That is, GCMs are a way to educate children including what is taught and how it is taught—i.e., a method of government-funded brainwashing. Similarly, the Thermostat hypothesis—for example—is of no greater gravity than that.
Dr Lacis,
[“Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect…”]
Can you confirm this means you think that ‘noncondensing greenhouse gasses’ (NCGG), which amount to less than 0.04% of the atmosphere, contribute appx 8.25 deg C of the (appx) 33 C Greenhouse Effect (33/4)?
Can you also confirm that, therefore, back in 1850 when the NCGG amounted to appx 0.028% of the atmosphere, the NCGG would have been responsible for 8.025 C of the GE (32.1C/4)? Where 32.1 represents the current GE less the 0.9 C warming since 1850. If you think the percentage contribution of CO2 was different in 1850,please tell me what it was. I use 1850 as that is the start of the IPCC’s ‘accurate data”.
Furthermore, can you therefore explain why a (roughly) 40% increase in NCGG, mostly made up of “the single most important climate-relevant greenhouse gas in the Earth’s atmosphere…”, has only contributed to an unknown portion of the 0.9 C warming observed in the last 160 years (or, by your own figures, a warming of appx 0.2 C)?
I would appreciate your explanation.
“Can you confirm this means you think that ‘noncondensing greenhouse gasses’ (NCGG), which amount to less than 0.04% of the atmosphere, contribute appx 8.25 deg C of the (appx) 33 C Greenhouse Effect (33/4)?”
No. Removing all CO2 from the system drops the temperature from plus15 to minus 22 degrees = 37 Degrees. Figure 2 of the paper.
DocMartyn,
This is not an answer to my question. What may or may not happen if – hypothetically – CO2 were to disappear from the atmosphere is entirely irrelevant to the statement [“Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect…”]
If NCGG are responsible for 25% of the 33C GE, then NCGG are responsible for 8.25 C. That is what I think Dr Lacis meant. I was simply asking him if that is, indeed, what he meant.
Your reference to Fig 2 of his paper is similarly irrelevant. The figure is based on a model. I would love to see any real-world evidence to support the assumptions made in coming up with that figure or the rest of the paper.
I would really appreciate Dr Lacis’ response to my simple questions.
I suspect that the figure relates to the proportion of LW absorbed by the different gases. The paper says the figure comes from ModelE. Therefore this posting from realclimate may be relevant. It states that if all other greenhouse gases are instantaneously removed, the amount of longwave absorbed by the atmosphere would be reduced to 26% of what it was.
http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/
Equally though, the link says that if CO2 were removed, the reduction would be to 91% (not 74%) because other gases absorb the radiation that CO2 would otherwise have absorbed. So the interdependences mean that picking a figure is not entirely straightforward.
PS. I see Alex quoted the relevant bit from the paper below.
Steve,
Thanks for the input and thanks for the tip about Alex’s conversation below. Here are my thoughts…
I agree with Alex that the way statements are presented is very much part of the problem. Dr Lacis makes the bold statement that NCGG account for 25% of the total GE. Whether this statement is due to the proportion of LW absorbed by these gasses or not is only known by the author. Unfortunately for Dr Lacis – and the authors of the link you provided – both sets of statements are entirely dependant on models, the input of which are, at least in part, dependant on the assumptions of the modellers. I say unfortunately because the assumption that NCGGs are responsible for 25% is unsupported by observed data. Arguments of ‘thermal inertial lag’ are equally unsupported by observed data.
To argue the lack of evidence by postulating what might happen if ‘all of one component disappears from the atmosphere’ is to hide from reality, in my opinion. According to DocMartyn’s point above (referencing Fig 2), total removal of CO2 would result in the global temperature dropping by 37 deg C. This would result in the planet being 4 deg C colder than if it had no atmosphere at all! Such a logical fallacy is what happens if people ignore the real world and set their stall by – in this case – the veracity of the radiative theory underpinning cGAW.
.
My questions stand to Dr Lacis. Did he really mean that NCGGs account for 8.25 C of the GE? In which case, how much of the GE in 1850 was due to CO2? If your point about LW absorption is correct, can you explain why the temperature has only warmed by 0.8 or 0.9 C for a relatively massive increase in CO2 of 40%?
All I am trying to point out is the rather obvious anomaly represented by observed data for the radiative forcing theory. I am sure Dr Lacis could clear this up. Or maybe not…
Regards,
To Arfur Bryant | October 12, 2011 at 1:18 pm:
“Did he really mean that NCGGs account for 8.25 C of the GE?”
No. It’s not a linear thing. I think the point he is making is that even if you remove all the other greenhouse gases there is still a substantial greenhouse effect due to CO2. If the planet were further from the Sun then there would still be a greenhouse effect of a certain amount due to the non-condensing GHG (nGHG) but it may not be sufficient to evaporate water and therefore the nGHG would cause almost *all* the warming. In a billion or so years time, the Sun will be warm enough to evaporate water and cause runaway warming even without no nGHG so maybe you could say then that the nGHGs are irrelevant.
The figures are obtained by applying a radiation model to an average atmosphere. The normal objections about predictability of GCMs don’t apply.
Steve,
You say: [“No. It’s not a linear thing. I think the point he is making is that even if you remove all the other greenhouse gases there is still a substantial greenhouse effect due to CO2.”]
.
Whilst I can accept that the relationship may not be linear, to argue non-linearity without putting forward exactly what type of non-linear relationship exists is essentially just hand-waving.
Once again, anyone using that argument has to explain why the observed data does not support the idea that CO2 accounts for 25% of the GE. Just saying “its not linear…” doesn’t cut it. What type of non-linear relationship would explain the following facts?:
1. Since 1850 the CO2 has increased by appx 40%.
2. Since 1850 the GE has increased by appx 0.85 deg C.
There is no escaping the logic that, if Dr Lacis is correct, the global temperature would have increased by much more than 0.85 C just due to CO2!.. As it stands, all we can say is that CO2 may or may not have contributed to an unknown portion of that 0.85C warming. We can’t even attribute all the warming to CO2 because to do that would ‘deny’ any form of natural variability. Hence the contribution of CO2 is less than 0.85C, and potentially much less since there have been warming periods prior to the late 20th century.
.
So it is beholden on whoever uses the ‘non-linearity’ argument to adequately explain what type or relationship exists. No-one seems to be interested in what contribution CO2 (and other nGHGs) made to the terrestrial GE back in 1850. It appears logical to me that we must be able to answer that question before we can hope to quantify the contribution made by CO2 today.
.
I have to conclude that the observed data does not support the argument put forward by Dr Lacis.
Geomagnetic field as global thermostat (or at least thermometer, either way with a credible correlation too)
http://www.vukcevic.talktalk.net/LL.htm
How does it work?
http://www.vukcevic.talktalk.net/NFC.htm
If operating mechanism isn’t clear, at least graphics are ok.
NAIVE TECHNICAL QUESTION: after extensive searching on the web (ok, only a couple of minutes) I can’t find an answer to this question:
Is CO2 concentration an output from as well as an input to GCMs?
Oh sure… GCMs have a built-in bias whereby human CO2 acts as an inexorable feedback mechanism–much like the fabled perpetual motion machine–that can only lead to catastrophic runaway global warming.
it is most often used as an input, although some of the more recent climate models include an interactive carbon cycle
Dr. Curry,
I have run across some references to limnology – the study of freshwater systems- that had some very interesting implications regarding the freshwater system impact on the carbon cycle.
I am wondering if you are aware of any of this?
I wrote to an author of a paper that was interviewed on a program but did not hear back. My bet is that you would find this very intriguing as well.
I would be pleased to give you the contact information of this author, if you would like it.
Here is an abstract regarding limnology that I believe will explain why I find the topic of interest irt climate:
http://www.aslo.org/lo/toc/vol_54/issue_6_part_2/2298.pdf
thx, this is something i know little about
You are very welcome.
The implications are significant for any discussion of carbon cycle. It would seem that we are not anywhere close to accounting for the carbon cycle.
hunter we don’t agree on much but earlier I proposed that the main issues with GCMs and skirted around by a lot of the explanations of the GHE can be categorized 2 ways 1) issues with parameterizations of physical processes occurring on sub-model grid scale (Dan Hughes provided examples) and 2) completeness of inclusion of all relevant processes, such as the biosphere carbon cycle, ocean mixing etc.
the main difference 1) vs 2) is the question changes from “dealt with adequately?” to “dealt with at all?”
It is interesting to consider how the authors have tried to deal with the issue of clouds. Here is an extract:
“In round numbers, water vapor accounts for about 50% of Earth’s greenhouse effect, with clouds contributing 25%, CO2 20%, and the minor
GHGs and aerosols accounting for the remaining 5%. Because CO2, O3, N2O, CH4, and chlorofluorocarbons (CFCs) do not condense and precipitate, noncondensing GHGs constitute the key 25% of the radiative forcing that supports and sustains the entire terrestrial greenhouse effect, the remaining 75% coming as fast feedback contributions from water vapor and clouds.”
The value of 25% for clouds is derived from the LW TOA change between having and not having any clouds by turning them on and off in the model. A normalised average change of 37.3W/m^2 is derived which equates to 24.4% of the total LW change in radiation. See Table S1.
An issue comes from whether this can be described as a fast feedback effect in response to the adding of the non-condensing GHGs. The issue being that the sign appears to be wrong. Figure 2 shows the increase in cloudiness when the non-condesning GHGs are removed, a change from ~58% to ~75% accompanied by falling temperatures. So lower temperatures are associated with more clouds and more clouds has separately been identified with more warming in the LW (which is where they are looking for the GHE). This is a negative feedback not the positive one that they seem to be indicating in Figure 1 and in the initial quote above. In terms of feedbacks the WV and clouds are operating in opposite senses, when one goes up the other down, it is not their sum but their difference that determines the size of the feedback.
This is problematic. The LW effect of the clouds is clearly large and positive but that alone does not make it a positive feedback. That would require that it varies with the concentrations of non-condensing GHGs in a manner that reinforces their effect which they demonstrate it doesn’t.
What to do? They could reverse the sign to show that it is a negative feedback but that would mislead in another way for the cloudiness varies by only a small proportion between with and without non-condensing GHGs so attributing the full ~25% would be unjustified.
They have correctly identified a source of LW warming due to the clouds but have described it as a positive feedback with no apparent justification and have included a figure which by itself indicates that it is a negative feedback. So which is it? Well obviously negative and obviously that changes the picture as presented qutie considerably.
It has been indicated that there is nothing novel in this paper. Well I think this is pretty novel. It is the first such paper I have read that fails to consider the sign of a response to a forcing before deciding whether it is a positive or negative feedback.
Alex
Alex – Maybe I’m missing something, but I didn’t see a problem with the attributions. Their addition/subtraction tests in which clouds were added or subtracted without other atmospheric changes showed clouds to be an important contributor to the greenhouse effect via their LW absorption properties, but as far as I can tell, it did not purport to show that clouds would disappear in the absence of CO2 and other non-condensable ghgs. To the contrary, Figure 2 shows a rapid increase in cloudiness following removal of non-condensable ghgs, with a consequent cooling effect due to increased albedo. This indicates that removal of clouds would reduce greenhouse effects and that removal of non-condensable ghgs would mediate cooling through the albedo effect of increased cloudiness, which is a positive feedback (less CO2 = cloud-mediated cooling). I don’t find inconsistencies in these estimates,
Fred,
I am concerned about what they actually say not how it really works. You mention SW effects which are definitely part of the feedback mechanism.
In their calculations they only consider the LW effect, (which is a bit bizarre), the LW effect of clouds (more clouds -> more warming) with the effect of temperature (higher temps -> less clouds) is a negetive feedback loop.
The issue arises over the use of the term feedback. In terms of contribution to warming the clouds make a 25% contribution but they describe the feedbaxk component as 25% (WV) + 25% (cloud LW).
To quote:
“… water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect.”
compare this with:
… water vapor and clouds account for the remaining 75% of the greenhouse effect.
They have shown the second statement to be true but they have aslo shown that the 25% due to clouds does not operate “via feedback processes” in the sense that they indicate for this contribution has the wrong sign and is only weakly coupled to the temperature. The clouds would be present if there were no non-condensing GHGs and only a very small proportion of them disappear when they are restored.
To quote more fully:
“Noncondensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapor and clouds via feedback processes that account for the remaining 75% of the greenhouse effect.””
In what way is the 25% due to non-condensing GHGs “sustaining” the current level of clouds? Take away the non-condensing GHGs and you get more clouds as you point out. Is this some wierd semantic logic where sustaining means reducing?
Perhaps the most interesting issue is why they chose not to quantify the SW effects of clouds which is a positive feedback. I really have no idea. Is it legitimate to quantify the GHE including it feedbacks without the SW effect? I think it might just be the biggest effect so I guess I would say no.
Alex
Alex – I revisited the article and supplementary material and found nothing to change my interpretation that their conclusions are consistent with their data and not mutually contradictory. They attribute all greenhouse effects as due to LW absorption, with 50% due to water vapor and 25% to clouds, with those particular percentages being the result of feedbacks. I don’t think they claimed that there would be no cloud greenhouse effects in the absence of non-condensing ghgs, or at least I didn’t interpret their results that way, given the increase in clouds when the non-condensing ghgs are eliminated. That does not conflict with the conclusion that the current levels are the consequence of feedbacks. Similarly, I also think they are justified in concluding from their data that the non-condensing ghgs are sustaining the current level of clouds and water vapor. I interpret “sustaining the current levels” to mean that without the non-condensable ghgs, the levels would differ from the current one. If you had preferred “maintaining” to “sustaining”, that might be less ambiguous, but I think I understood what they meant the way it was stated.
I’m not sure what you had in mind regarding the SW effects, which they see as contributing a net cooling positive feedback effect to the cooling from eliminating the non-condensables. Quantifying the GHE as a function of absorbed or reflected SW might be of some interest but I don’t think that was the topic of their paper. I’m not sure the relative contributions of condensable vs non-condensable ghgs would change dramatically, but I don’t know for certain.
Maybe some of this is semantic, but I really had no quibbles with their statements as I interpreted them.
Also, as a small point of semantics regarding the “sustaining” term, they lumped water vapor and clouds together in attributing the levels to feedbacks. I don’t really think they intended to say that the feedbacks made the cloud levels higher than they would have been otherwise, and I wouldn’t have judged that to be their intention given the context showing a difference in the opposite direction. I think what I’m saying is that I interpret them to conclude that the non-condensables contribute 25% to the GHE, water vapor 50%, and clouds 25%, that these particular percentages are the result of feedbacks, and that without the non-condensables, the GHE would be much smaller and the planet colder. I didn’t interpret them to say much beyond that.
Fred,
It is simple. In what way is the cloud part due to a feedback.
yours “… with those particular percentages being the result of feedbacks”,
On what is it a feedback?
As far as I can gather you would find their statements statisfactory if without non-condensing GHGs we had 75% clouds and with we had 74% clouds because the “particular percentage” 74% was due to the GHGs.
They have shown that the clouds coverage is self-sustaining that is neither due to, nor much modified by the levels of non-condensing GHGs. It is neither sustained by them nor does it rely on them for stability. They have shown that it is stable over a wide range of temperatures.
They have shown that the warmiong due to cloud coverage is a significant effect (of the order of the non-condensing GHGs) and that it is a largely independent one.
It is no more a feedback, than CO2 is a feedback It is an independent part of the GHE that much they have shown. For instance how much of the non-condensible part of the effect would have gone away if the surface temperature was lowered by 30C?
What they have shown is the the cloud coverage is surprisingly stable, perhaps the most stable of all the contributing parts of the GHE.
Regarding SW, if clouds are part of the GHE and they wish to maintain that clouds are not a sepearate element but due to feedbacks on the forcings produced by non-condensing GHGs then all of the warming/cooling effects of the clouds come into play. That is the danger of declaring them as a feedback. They inherit the GHE rather than source it and all their effects become relevant because they are under the “control” of the non-condensing GHGs.
Finally English can only stand so much abusage and Sign Matters!
How often are a gambler’s loses considered to sustain or maintain his prosperity?
Alex
Fred,
Here is another quote:
“Because CO2, O3, N2O, CH4, and chlorofluorocarbons (CFCs) do not condense and precipitate, noncondensing GHGs constitute the
key 25% of the radiative forcing that supports and sustains the entire terrestrial greenhouse effect, the remaining 75% coming as fast feedback
contributions from water vapor and clouds.”
Please note the usage of “entire” in: “… sustains the entire terrestrial greenhouse effect”, this we know not to be true. The figures indicate this is a false statement. If you will grant me that we know that the “entire” effect is neither sustained (for it doesn’t go away without the non-condensing GHGs) or supported (it has the wrong sign relationship to the non-condensing GHGs) and that the author’s know this to be the case, that would amount to a deliberate falsehood. I can think of no other meaning of “entire” other than full, complete, total.
The word “entire” is critical, without it one could argue that we understand what is meant, with it the statement is flat out false.
I may stand to be corrected but I do not see anywhere in the text that this misrepresentation is corrected or caveated. It is apparent from the figures. Without the figures I and perhaps others would have taken the quoted sentence as a true and fair representation. I say that it is neither a true nor fair representation.
I think it important that articles such as this one, whose purpose seems to be to put the record straight do so in a way that is fair, open and honest with its audience, using words in a way corresponding to normal usage, getting facts straight and revealing the difficulties and covering the likely ambiquities.
Alex
Fred,
Here is yet another quote:
“This allows an empirical determination of the climate feedback factor as the ratio of the total global flux change to the flux change that is attributable to the radiative forcing due to the noncondensing GHGs. This empirical determination leads then to a climate feedback factor of 4, based on the noncondensing GHG forcing accounting for 25% of the outgoing flux reduction at the TOA for the full-constituent atmosphere.”
If this is not meant to imply that the feedback response due to WV and clouds multiplies the effect by a factor of 4, I do not know what it intends. If it is not meant to imply that the 25% due to non-condensing GHGs is “entirely” responsible for 100% (the entirety) of the GHE, I do not know what it intends. I think they be disseminating a nonsense.
They continue:
“This implies that Earth’s climate system operates with strong positive feedback that arises from the forcing-induced changes in the condensable species.”
It is clear that the 25% due to clouds acts slightly in the wrong sense so it is not part of the “strong positive feedback”, further the effects of WV are not entirely removed so by their logic the “climate feedback factor” is somewhat less than 3. I say their logic as I do not think it is a sensible approach.
Perhaps stating 4 as opposed to less than 3, and entirely as opposed to partially are:
“Close enough for Climate Change”.
Alex
Alex – Although you’ve elaborated on your first comment in a way that makes it clearer to me, I can’t agree with your conclusion that the paper makes serious misstatements. At worst, some of the terminology can be misinterpreted to mean something unintended, but the context of the paper makes the authors’ meaning clear to me, and I have no problems with their argument.
Basically, what I understand them to say is (a) CO2 and other non-condensing ghgs (hereafter just CO2 etc.) mediate cloud and water vapor feedbacks; (b) these lead to a combined GHE contribution from clouds and water vapor of 75% (25/50 respectively); (c) therefore, CO2 etc. are entirely responsible for this apportionment, because; (d) without CO2 etc., clouds and water vapor would be different, the combination of greatly diminished water vapor and slightly increased cloud cover would significantly reduce the GHE, and planetary albedo would increase significantly via both ice and clouds, with a net cooling effect.
Does the paper claim that without the feedbacks that lead to the 75% figure, clouds and water vapor would contribute no GHE, or that the direction of cloud LW changes alone is a cooling one? To me, it is obvious the paper does not make such claims – it never states that CO2 etc is responsible via feedbacks for the entire GHE of the current climate, but only that CO2 etc “supports and sustains” the entire effect. Evidence that they don’t imply an entirely absent GHE in the absence of CO2 etc. lies in Figure 2, which I believe supports the statements made in the paragraph above this one. Even if we ignore cloud cover (which increases) and just consider water vapor, the latter doesn’t disappear completely, and so I don’t see how this could be reconciled with an interpretation of “entire” other than the one I stated.
I guess my main disagreement with you is whether our disagreements are important. I think they involve semantics only, and would be resolved if the authors had described their conclusions in terms more to your liking, including a clear statement that their use of the term feedbacks did not imply an absence of GHE in the absence of feedbacks. I agree that would have been helpful. However, I expect most readers have been willing to interpret the paper as I believe the authors intended, and have found its arguments plausible and consistent with the cited data.
“Basically, what I understand them to say is (a) CO2 and other non-condensing ghgs (hereafter just CO2 etc.) mediate cloud and water vapor feedbacks; (b) these lead to a combined GHE contribution from clouds and water vapor of 75% (25/50 respectively); (c) therefore, CO2 etc. are entirely responsible for this apportionment, because; (d) without CO2 etc., clouds and water vapor would be different, the combination of greatly diminished water vapor and slightly increased cloud cover would significantly reduce the GHE, and planetary albedo would increase significantly via both ice and clouds, with a net cooling effect.”
I think you are saying that you interpret them as saying what is true, the issue is that they are not.
They state:
“This empirical determination leads then to a climate feedback factor of 4”
This states that the 25% is enhanced by a further 75%. This is downright false and we know that. This is a gross misrepresentation.
“Does the paper claim that without the feedbacks that lead to the 75% figure, clouds and water vapor would contribute no GHE, or that the direction of cloud LW changes alone is a cooling one? To me, it is obvious the paper does not make such claims – it never states that CO2 etc is responsible via feedbacks for the entire GHE of the current climate, but only that CO2 etc “supports and sustains” the entire effect. Evidence that they don’t imply an entirely absent GHE in the absence of CO2 etc. lies in Figure 2, which I believe supports the statements made in the paragraph above this one. Even if we ignore cloud cover (which increases) and just consider water vapor, the latter doesn’t disappear completely, and so I don’t see how this could be reconciled with an interpretation of “entire” other than the one I stated.”
See my comment above: Yes they do say that the 25% leads to the 100%.
“I guess my main disagreement with you is whether our disagreements are important. I think they involve semantics only, and would be resolved if the authors had described their conclusions in terms more to your liking, including a clear statement that their use of the term feedbacks did not imply an absence of GHE in the absence of feedbacks. I agree that would have been helpful. However, I expect most readers have been willing to interpret the paper as I believe the authors intended, and have found its arguments plausible and consistent with the cited data.”
It is strange that when certain people engage in falsehoods it is a matter of semantics.
To make things easier I have chosen to concentrate on just one of their statements where it is directly stated that there is a multiplication of 4 from cause to total effect. That is not a semantic point, it is a gross misrepresentation of fact.
Alex
Alex – Because our discussion is becoming repetitive, I’m afraid we will simply have to agree to disagree. I find the arguments in the paper plausible, and supported by the data, based on what I perceive to be a reasonable interpretation of what the authors claim, and how they define the terms they use. I’ll summarize briefly.
They define “fast feedback processes”: This identifies water vapor and clouds as the fast feedback processes in the climate system.” This term is not used to describe the feedback mechanism but rather the climate phenomena involved in the feedback.
They define “feedback factor”: ”The ratio of the total climate response to the no-feedback response is commonly known as the feedback factor”> This is one of several definitions of feedback factor I’ve seen in the literature, but is the one with which their data should be compared. Note that a “no-feedback response” refers to the response to a forcing. In this case, it is the response to CO2 and other non-condensables. Water vapor and clouds are not forcings even though they would exist and exert radiative effects in the absence of the non-condensables.
They discuss how this is analyzed: ”This allows an empirical determination of the climate feedback factor as the ratio of the total global flux change to the flux change that is attributable to the radiative forcing due to the noncondensing GHGs. This empirical determination leads then to a climate feedback factor of 4…. A clear demonstration is needed to show that water vapor and clouds do indeed behave as fast feedback processes and that their atmospheric distributions are regulated by the sustained radiative forcing due to the noncondensing GHGs… The results, summarized in Fig. 2, show unequivocally that the radiative forcing by noncondensing GHGs is essential to sustain the atmospheric temperatures that are needed for significant levels of water vapor and cloud feedback.”
Note that they don’t claim that clouds and water vapor are present only because of the noncondensing GHGs, but that they are “regulated” by the latter, which sustains significant levels. Figure 2 makes clear that intended meaning – I don’t see how that could be interpreted any other way. They combine clouds and water vapor into a single entity whose level reflects the effect of that regulation. There is no claim that the LW effects of clouds in isolation are reduced by the absence of the noncondensables, although it is interesting that if there were no feedback reduction in water vapor from the loss of the noncondensables, cloud cover would be much higher than the quantity in Figure 2.
In Table S1, they document the apportionment of effects. Fractional removal of CO2 imposes a 21% LW flux change out of the total (about 22% with inclusion of the other noncondensables), while water vapor and clouds account for 74%. It therefore appears as though the total climate contribution to LW flux is slightly greater than 4 times the noncondensable (forcing) contribution.
However, this is not the best way to view feedback factors, and it involves LW flux only. Furthermore, residual water vapor and clouds subtract from LW cooling effects, while, while albedo changes add SW cooling. A more common question is the extent to which the temperature response to a forcing is amplified (or diminished) by feedback effects. This can be ascertained from the data in Table S1, Figure 2, and Figure S1. From the next-to-last column in Table S1, we learn that CO2 contributes about 31 W/m^2, which translates into a temperature change of about 9 deg C. From Figure 2, we find the total change that occurs after the feedbacks operate is about 37 deg C, while the use of a different model in Figure S1 gives a figure of about 27 deg C. The Figure 2 comparison puts the feedback factor at slightly over 4, while the Figure S1 comparison makes it about 3. An average value is about 3.6, with the variation dependent on the model, but not radically different from 4. Their main conclusons are supported.
I have now reread the paper and supplements a few times. I can agree that the text contains ambiguities, but I believe they are resolved by the figures and tables. I have not found any misstatements of fact. They paper is not groundbreaking, but it is a solid restatement of principles, with some quantitation attached that appears logically derived from the evidence presented.
The Figure 2 temperature drop of 37 deg C (feedback factor 4.1) may be a better indicator than the Figure S1 drop of 27 deg C (feedback factor 3), because in the latter simulation, the climate is still losing heat at the end of the run.
“Everything has to be taken on trust; truth is only that which is taken to be true. It’s the currency of living. There may be nothing behind it, but it doesn’t make any difference so long as it is honoured.” (Stoppard)
There are many honorable positions. Presenting as true is honorable even when erroneous, if done honestly. Presenting dishonestly is dishonorable even if true.
Many of the statements are misrepresentations.
I can see the issue. If it is accepted that they are false statements, alternatives are that they from ignorance or deceit. Neither would ever do.
So the currency is debauched for their sake and what liitle truth there is in the world is of less value. Eventually lies and truth will obtain partiy. Those that feast in ambiquity and those that watch on silent or present apologia are culpable in a dishonorable trade.
I do not agree to disagree but I will lament the passing of truth.
I quote from below:
A Lacis: “If you take away the non-condensing greenhouse gases, water vapor will condense and precipitate, and you will be left without a greenhouse effect.”
Arthur Bryant: “Are you sure?”
A Lacis: “My statement that “If you take away the non-condensing greenhouse gases, water vapor will condense and precipitate, and you will be left without a greenhouse effect.” is clearly more rhetorical than literal.”
“Everything has to be taken on trust; truth is only that which is taken to be true. It’s the currency of living. There may be nothing behind it, but it doesn’t make any difference so long as it is honoured.” (Stoppard)
Alex
To Arfur Bryant:
Sorry for making you Arthur, I was negligent and disrespectful.
Alex
It’s interesting to me that water vapour and clouds are identified as separate entities contributing to the total GH effect, even though clouds are made up of errr..water vapour. Forgive this engineer if I am incorrectly assuming that the water vapour in clouds emit DLR as well. So the total GH effect due to water vapour is 75%. The fly in the ointment being how cloud formation is affected by temperature or other processes and how much SW radiation is reflected back by said clouds.
Obviously not a Chem E. Clouds are condensed water vapor and have very different absorption and emission characteristics. Apples/Oranges
Elect. Eng. just so ya know.
The atmosphere absorption spectrum that I have been able to find do not differentiate between H2O liquid/ice/vapor absorption bands, especially in the MIR and FIR wavelengths where the “greenhouse effect” is realized. If I could be pointed to such info, I’d appreciate it.
Solid and liquid water absorb/emit as effectively black bodies. Only the vapor has bands…
water spectra:
http://en.wikipedia.org/wiki/File:Water_absorption_spectrum.png
water ice spectra:
http://www.psrd.hawaii.edu/WebImg/europafig1.gif
water vapor spectra:
http://wattsupwiththat.files.wordpress.com/2008/06/atmospheric_spectral_absorption.png
“Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today’s climate models include accepted values for the climate’s sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.
“The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. ‘Some feedback loop or other processes that aren’t accounted for in these models — the same ones used by the IPCC for current best estimates of 21st Century warming — caused a substantial portion of the warming that occurred during the PETM.’”
(From a Rice University 7/14/2009 Press Release concerning a study authored by Gerald Dickens and appearing in Nature Geoscience: Global warming: Our best guess is likely wrong — Unknown processes account for much of warming in ancient hot spell)
“In a nutshell, theoretical models cannot explain what we observe in the geological record. There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.” ~Gerald Dickens
must be that thermostat
I have to empty a lake. The only tool I have is a spoon. Therefore I can l empty the lake with a spoon. Or not.
The fact that GCMs are the only tool the consensus has to do “experiments” on the global climate does not mean their results are accurate. It may mean there is no way to do such “experiments.” But perhaps for those so invested in climate models, that is an alternative that simply does not come to mind.
On another tack, since the GCMs were created and are run by those who are certain that CO2 is the Earth’s climatic thermostat, is it any surprise that their results conform to their beliefs? If the models showed something different along the way, wouldn’t the modeler “correct” the model to better reflect “reality” as he knows it? How would we know either way?
If this were merely an academic exercise, the “best that we have” argument might be persuasive. But the stakes here are rather higher than that.
I am not sure how anyone can argue that CO2 is any sort of major thermostat controlling the Earths temperature.
http://www.biocab.org/Geological_Timescale.jpg
http://www.biocab.org/carbon_dioxide_geological_timescale.html
historically the change in temperature precedes the change in CO2. While CO2 may be a minor player it is pretty obvious that there are other factors that bear far more impact and override any greenhouse influence Co2 may have.
As has been pointed out earlier in this thread, at the moment Earth is in a relatively cool phase with impoverished atmospheric Co2 levels. To find Earths normal one has to go back farther than 150,1500 or even 15,000 years.
That one has been hacked to death, and the answer tells you why things are dangerous these days http://www.skepticalscience.com/co2-lags-temperature.htm
——————————————
This statement does not tell the whole story. The initial changes in temperature during this period are explained by changes in the Earth’s orbit around the sun, which affects the amount of seasonal sunlight reaching the Earth’s surface. In the case of warming, the lag between temperature and CO2 is explained as follows: as ocean temperatures rise, oceans release CO2 into the atmosphere. In turn, this release amplifies the warming trend, leading to yet more CO2 being released. In other words, increasing CO2 levels become both the cause and effect of further warming. This positive feedback is necessary to trigger the shifts between glacials and interglacials as the effect of orbital changes is too weak to cause such variation. Additional positive feedbacks which play an important role in this process include other greenhouse gases, and changes in ice sheet cover and vegetation patterns.
Where is the math?
I see an explanation, but what was the change in the ocean temperature and ocean CO2 levels.
SS kindly provides links to a number of papers on the subject.
Does SS have any links to explain why the current atmospheric Co2 and current temps are both well below what those levels have been for the last 150 million years ?
I have a hard time looking at a mere 150 years and calling that normal for things that have varied for several hundred million years with absolutely no anthropological influence at all and are currently at the lower end of the scale
Jim,
I think the concept of “normal” conditions is pretty meaningless. AFAIK there is nothing particularly special about current conditions, other than they are what we are used to and they have been relatively stable during the last 10k years or so. In that context what conditions were like hundreds of millions of years ago is rather irrelevent, what they may be like in a hundred years is more significant.
Andrew if you want to define “normal” as the last 5K years then I can point out a number of periods where temperature fluctuations of plus or minus 2 degrees C have been documented.
Do a bit of research starting at appx 1450–1300 BC then move forward to around 250–0 BC, we also have the period from 800–1100AD, and of course the LIA of 1300 -1800 AD. I would love to see an article or paper demonstrating how the CO2 “thermostat” hypothesis correlates or fails to correlate with the temperature fluctuations of those periods.
I am not saying Co2 has no effect at all, but in my admittedly layman’s perspective there are many more factors of which we only understand a fraction of which obviously have more influence than Co2.
Jim,
Well 2C is pretty small beer compared to the temperature changes between glacials and interglacials and even smaller compared to temperature changes even further back in time. But I don’t see any record which shows even a 2C variation in the last 5k years – even if one takes the most extreme estimations of the MWP and LIA for example they were not of that magnitude
Andrew, the Medieval is by far the most well known but it is not the most drastic temperature fluctuation of recent (10K years) history. The Holocene climate optimum periods and the Roman Warm periods were warmer than the MWP according to most scholars. Bearing that in mind, just as with today’s warming period you pick your paper, pick your proxy, then pick your region. None will agree with each other anymore as to the magnitude or even the dates of the occurrences any more than GISS, HADCrut3, UAH and RSS temperature databases are in 100% agreement with each other now.
The challenge still remains however. Does the Co2 thermostat hypothesis fit the Holocene optimum, RWP, MWP, and LIA or doesn’t it? I see a lot of discussion here over about he last 150 years but if the Co2 thermostat hypothesis it should be valid for all climate fluctuations over the last 10K years. If it isn’t then then more research is needed to identify the factor(s) involved in historical fluctuations are identified and the hypothesis of Co2 as the main regulator of Earths temperature is invalid until those influences are identified and quantified.
Eli: I’m sure you’re more familiar with the Vostok data and literature than I am, but for me at least the apparent tendency for any given temperature to be associated with higher CO2 levels during cooling periods than during warming periods is difficult to reconcile with more than a trivial feedback effect from CO2. That’s if the tendency is real. However I accept that the matter may need the attention of a competent statistician to clarify. However if the issue is considered important (and I believe that it is) an even more pressing need is for more Vostok type data to be acquired, i.e. more long cores through the Antarctic ice.
Coldish,
What’s the best web link to quickly look at what you’re describing.
It matches what I hypothesized to hunter above, except I was joking.
Bill
Hi BillC: have a look at http://globalwarming.chemcept.co.uk/gwappendix.htm
The author is WR Johns. There are problems, especially the fact that the Vostok CO2 values and proxy temperatures are not simultaneous (not from exact same depths in the core), so interpolation is required. But assuming Johns did his plotting correctly he seems to have a prima facie case. As I indicated above, I think there’s a need for more work on the topic. Coldish
Coldish,
I took a quick look, and I will try to take a longer look later. One question I have is, we see the generally higher CO2 concentrations during cooling periods, but I wonder if it can be determined at the granularity of the ice core data what the dCO2/dt is doing at these times. As I said to hunter, evidence of CO2 continuing to rise after temperatures start to cool (or continuing to fall for a while after temperatures start to warm) would be evidence to me that the forcing->feedback would lie mainly in the direction of T->CO2 rather than CO2->T.
Eli I am not sure how anyone could look at the graph I linked and see any correlation whatsoever in the Co2 and the temperature and even if one massages/tortures the data into a rough fit that even you admit lags it still does not override the fact that both temperature and Co2 levels have been much higher than they are at present.
If you want to concentrate just on recent history see if you can explain the Co2 and temperature trends from the Cretaceous through the Oligocene periods.
“If you want to concentrate just on recent history see if you can explain the Co2 and temperature trends from the Cretaceous through the Oligocene periods.”
Does anyone have data from ice core that shows CO2 levels from say 1860 to 1960.
I don’t mean a splicing of data but just the ice core data.
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/law/law_co2.txt
The Rabbet’s Right on the CO2 point, though higher concentrations have more than just a radiative impact. The issue should be that the Manabe model was more accurate and getting the models more in touch with reality is what’s needed.
Weird, switched my name on me.
OK, this is off topic so should be deleted promptly, but the more I read about the consensus’ growing obsession with CO2, the more I think about General Jack D. Ripper’s obsession with fluoride in Dr. Strangelove.
“It’s incredibly obvious, isn’t it? A foreign substance is introduced into our precious [climate] without the knowledge of the individual. Certainly without any choice. That’s the way your hard-core [oil industry dupe] works.”
Doesnt much of this come back to the Salby observation:
The data shows that there is no significant trend in the d13C isotope data in comparison with the total C flux.
Therefore to use current GCMs to double CO2 as a proxy for anthropogenic activity lacks an empirical basis.
I didn’t know that coupling was supposed to have an empirical basis. I always thought that it was a convenient benchmark, and nothing more.
I’ve also thought it strange that the scenario mongering happens to work out to a doubling by 2100, but I guess coincidences happen.
It’s slated to double well before 2100.
Depends on the scenario analysis. “Business as usual” is not very likely for reasons not having anything to do with climate.
http://www.esrl.noaa.gov/gmd/webdata/ccgg/trends/co2_data_mlo_anngr.png
“September 2011: 389.00 ppm ”
“It’s slated to double well before 2100.”
Double what? 280 ppm- an estimated number.
Or doubling the current 389 ppm?
From 1960 of below 320 ppm to 2010 of 386.80, there was a rise of about 70 ppm over a 50 year period.
If one is doubling 280 and therefore 560 ppm or increase of 171 ppm from current level [45% increase] I suppose that is possible in 90 years.
But since began predicting where CO2 level would in next decade or two, they have predicted wrong. Coupled with fact of unexpected growth of Chinese CO2 emission- China might double US CO2 emission within the next decade. And everyone though the US emission was the problem.
This is one where you can predict accurately. From an accurate accounting of fossil fuel emissions, we know exactly how much atmospheric CO2 it will produce. This is well calibrated.
If we happen to emit a lot less in the near future, we have either hit a severe depression or have found some wondrous form of alternate energy.
And your point is?
“If we happen to emit a lot less in the near future, we have either hit a severe depression or have found some wondrous form of alternate energy.”
What about if we merely continue with the present depression?
Extend the trend for another 4 years?
Will that be this serious depression you seek?
280.
I believe global GDP is currently positive.
This is one where you can predict accurately. From an accurate accounting of fossil fuel emissions, we know exactly how much atmospheric CO2 it will produce. This is well calibrated.
Actually the statement is very incorrect.The uncertainties if fosssil fuel emissions is around +/- 6% eg Marland 2009 Sarmiento 2010
(OECD) countries may have—on average—an uncertainty
of 5% to 10%, whereas the uncertainty may be 10% to 20% for other countries. The International Energy Agency did not report the
uncertainty of its emissions estimates but relied on Intergovernmental Panel on Climate Change (IPCC) methodologies and cited the IPCC estimate that “for countries with good energy collection systems, this [IPCC Tier I method] will result in an uncertainty range of±5%. The uncertainty range in countries with ‘less well-developed energy data systems’ may be on the order of ± 10%.”
IE The information is neither independant or well verified.
You really have absolutely no idea what you are talking about.
In any case, +/- 6% is very good for analysis. Take +/- 6% year over year and it will converge as a CLT.
Actually you do not understand eg a change of sign in the emissions increases/decreases the carbon sink assumptions in the carbon cycle ie it sinks Le queres assumptions.
The small error in the 2 estimates for the US of around 0.9% seems trivial,however the the absolute value of this difference
was greater than total emissions from 147 of the 195 countries analyzed.(Marland 1999) .Try negotiating that assunption.
This is just insane nit-picking that has absolutely no utility for data analysis.
The Salby argument is a red-herring. The important point is that excess CO2 has a long adjustment time within the carbon cycle, but a relatively short residence time in the atmosphere. If there is one area that I think the climate scientists have been sloppy, it is in not driving that point home.
So what happens to global temperature from the models with a stable input of CO2? does it represent the warming since the little ice age or the cooling that many think is happening now or something else?
You need to throw in the pioneer effect, the great land clearances in the Americas and Australia.
Australia has been fire stick farmed for at least 60,000 years. So there are 2 aspects to clearing. Firstly it is about 11% (about 3% urban) of the total land area since European settlement – and this was of open grasslands mostly that were themselves the product of fire stick farming. Rainforest has increased in area as a result of less burning resulting also in most open forest converting to dense stands of what we call woody weeds – with dire biodiverstiy implications. People have talked of claiming carbon credits for it. There are much more worthwhile avenues available.
It was hardly a ‘great land clearing’. And from my meagre reading of American forestry – the ‘great clearing’ there had started to reverse from the 1850’s.
“You need to throw in the pioneer effect, the great land clearances in the Americas and Australia.”
Eli, Do I sense a ray of enlightenment?
In the absence of greenhouse gases, would there still be a troposphere?
Yes, because of the Chapman cycle and the dry adiabatic lapse rate, so there would always be an inversion due to ozone absorption and it is the reversal of the fall of temperature with altitude because of the ozone absorption that defines the stratosphere and troposphere
Without a Doubt!
Thanks for the reply, but with all respect, not responsive. The question is: what is the output of GCMs with flat CO2 input?
Sorry, this is in response to Eli Rabett at 9:17
I think that is called a “weather forecast”.
Seriously, I believe many of these GCMs are used for doing weather forecasting.
Simply put, models are validated by running them with constant levels of greenhouse gases and compared against various aspects of climatology (ie. how well or badly do they represent the real weather and climate). If they showed warming or cooling under these conditions then they would be “wrong”.
An IPCC emissions scenario run is a perturbation experiment. Basically a scientist is saying “Without changes in greenhouse gases my model temperature is stable on long timescales. With prescribed changes in greenhouse gases my temperature rise is X”.
Please forgive me if this has been covered already.
The following is a declarative statement:
CO2 can never reach a saturation concentration in any atmosphere.
If this declarative statement is true, the following must also be true.
CO2 must absorb some amount of radiative energy across the entire spectrum of EMR.
Because if there is part of the spectrum that is 100% transparent to CO2, then that energy will always pass through, hence saturation.
Or am I missing something?
JE
What you’re missing is that in the low concentrations that we’re talking about (even 1000 ppm is only 0.1%), it becomes a game of if you shoot a photon in the air, what are the odds of it hitting a CO2 molecule v.s. sailing out to space. That’s always a chance that it’ll sail out to space. You can’t guarantee that it’ll hit something.
But the spectrum of available photons is much wider than the absorption spectra of CO2.
One could equally make an argument that water vapour is the most important greenhouse gas because it is more prevalent, variable and not well mixed at all. It seems precisely the wrong kind of science – metaphysical and philisophical, providing no answer to new questions at all and not adding anything practical or substantive to the discussion.
A carbon tax was passed in the Australian Parliament this morning – albeit with 14% public support. I have little doubt that Lacis supports a carbon tax – and he uses the dispassionate language of science to persue this pernicious, growth limiting ideology. Science as advocacy for a one dimensional solution. So be it but the street cred. of science has and will continue to take a battering.
Meanwhile, the real issues are being resolved far from the madding crowd. Conservation farming is used on 15% of Australian crooping lands and is expanding rapidly. It provides productivity boosts of 70% to 100%, reduces weedicide use by up to a factor of 20, reduces nutrient applications and labour requirements. And has the potential to sequester 150 Pg of carbon in cropping soils in Australia.
There are other systems for land management with fire and for getting deep rooting on pastures that are being researched and implemented widely in Australia. Both sequester carbon and the latter drought proofs properties.
Chief,
You have my deepest sympathies.
I hope your nation is able to arrange for a speedy election and a good boot to kick out these wannabe elites from damaging your country further.
It is notable that the last pseudo-science social mania, eugenics, also hit Australia’s leadership hard and resulted in terrible laws being imposed on Australians as well.
When one makes a policy decision, it is assumed that the system for which the policy is applied can be ‘controlled’; otherwise, the policy is useless. So, here’s the question for any climate policy: Is CO2 the thermostat (control device)? Is the climate controllable? Better yet: Is the system observable? Is the system identifiable? (Insert typical control theory questions here.) Can humans manipulate CO2 concentrations sufficiently to control the climate?
To me, control theory must answer this ultimate question.
To properly answer these questions, the ‘control theorists’ need proper answers to the various questions: Observability, Identifiabilty, etc.
To provide the ‘control theorists’ with the needed answers, you need accurate description of the overall system and an accurate estimate of the feedback parameter(s). You cannot control without feedback-enabling, control parameters.
Now, I am neglecting various concerns associated with accurate data, model identification, model estimation, model testing, model validation, etc.
In my lowly opinion, the current state of climate policy assumes controllability.
As I recall, when I was a kid, there was a ‘Get Smart’ episode on TV where KAOS was trying to ‘control’ the weather. Did KAOS succeed? ;)
“When one makes a policy decision, it is assumed that the system for which the policy is applied can be ‘controlled’; otherwise, the policy is useless.”
What ‘system’ do you mean here? If you mean Australia’s energy production, then yes, this system and can be regulated, just as road traffic can be regulated (but not actually controlled).
If you mean the climate system, then no, it can’t be ‘controlled’ by Australian policy. But neither can Australian military policy and budgeting control what happens in the rest of the world. This kind of policy-making is about risk-management, not control, and, as with the analogised military policy, it is buttressed or challenged by choices other state governments make, either in concert, on their own, or with regard for the military policies of other countries.
Dr Roy Spencer’s analysis about Increasing Atmospheric CO2: Manmade…or Natural?
Some extracts
Eric
That is why there was no change in the GMT trend form 0.06 deg C per decade since record begun 160 years ago.
What a stinking mess good ole Roy-boy made out of that analysis. That is embarrassingly bad.
WHT
Show where Roy is wrong and post it here. I love to see your corrections!
Why the name-calling?
Roy, to his credit, posted Ferdinand Engelbeen’s comprehensive response.
Nick,
There are huge flaws in Engelbeen’s pseudo “rebuttal”:
1) No explanation for T° decrease from 1980 to 1910 then from 1940 to 1970 while [CO2] had steadily increased.
2) No explanation for the absence of warming over the past 14 years whereas [CO2] has steadily increased.
3) No explanation for comparable warming rate (0,15°C per decade)over [1910 and 1940] and [1970 – 2000] periods whereas the rate of [CO2] increase was almost 3 times lower (and the rate of CO2 emissions 5 times lower)
For all these issues the answer is the same : [CO2] is just not the climate driver !
Changes of [CO2] follows changes of PDO and subsequent changes of T°
Too much of a mess to correct. Roy-boy just has to start from scratch and pay attention to the size of the differential [CO2] changes. These are like 1 PPM per degree change in a short interval of time and they track both increases and decreases in temperature so they do not accumulate as much as emissions, which are cumulatively monotonically increasing. For the benefit of the doubt, I placed a long-term positive feedback on the CO2 outgassing and it still has at most 20% of the fossil-fuel amount (and if this is mainly a feedback from AGW it is not necessarily natural either, but a nasty side-effect).
Everything documented here over the past month as I worked out the problem:
http://theoilconundrum.blogspot.com/2011/10/temperature-induced-co2-release-adds-to.html
http://theoilconundrum.blogspot.com/2011/09/sensitivity-of-global-temperature-to.html
http://theoilconundrum.blogspot.com/2011/09/missing-carbon.html
http://theoilconundrum.blogspot.com/2011/09/derivation-of-maxent-diffusion-applied.html
http://theoilconundrum.blogspot.com/2011/09/fat-tail-impulse-response-of-co2.html
WHT,
Your demonstration is just as flawed as Englebeen’s anwer to R. Spencer.
Look at my answer to N. Stokes just above.
You don’t even know what my analysis involves. I am in no way trying to explain the temperature increase. I am mapping the temperature increase to a positive feedback CO2 increase.
But to lay waste to your argument is not too hard either. You basically cherry-pick timeline segments at your convenience. A cherry-picking cherry-picker, definitely not worthy of a statistical scientist.
Yep that is messy. It is partially correct though. Complicated issue, which, honestly, you have a fairly good handle on Webby.
There is a massive hole in Spencer’s formulations, one he establishes himself.
Without even going into the argumentation that follows, this fact with which he begins is missing from his following accounting and fatally flaws the rest.
Thanks for pointing that out. That line of reasoning is emblematic and a hallmark of the climate skeptics’ wild flailings. Some aspect of the data that overall supports the man-made hypothesis, but is not investigated as much according to their liking means that the whole premise is flawed. This particular one is part of the “Missing Carbon” argument that they like to bring up.
In fact the missing carbon is perfectly explained by a diffusional impulse response to CO2 sequestering kinetics. Anybody that has taken a single year of statistical mechanics in school can derive this result. I went the extra mile and fit the carbon-cycle model here:
http://theoilconundrum.blogspot.com/2011/09/derivation-of-maxent-diffusion-applied.html
Judith, Any chance of getting Paul Williams to write a guest post on numerical problems in climate models. I’d do it myself, but I don’t really have the time.
Yes, this would be really interesting. The scaling issues are, I think, important. In my field, very small effects, localised at a certain point, can total influence the model, as happens in real life.
My point is that the effects that give the heart its pathological behaviour are ones that one might dismiss as a “third order effect”, although this happens because the heart’s electrophysiology is spectactularly non-linear.
I have felt for long time that I would like to see a clear list of assumptions in GCMs, rather than trying to unravel them from a mass of rather turgid equations.
Hansen sets it out well.
As regards terminology, equations may suggest a better way to express oneself. Were one French, which I’m not, one would simply say:
“As I speak the most beautiful language in the World, why should I learn English?” (!)
I see you have quoted me! Imitation is the sincerest form of flattery!
Yes, I thought you put it very well.
Yes, it is beautiful description of the model. Have the results been shown to be accurate in the 30 years since it developed?
Hansen’s 1988 model was based on a climate sensitivity of 4K. Adjusting for current understanding of climate sensitivity (~3K) this early model did quite well at projecting temp rise and spatial distribution of temperature changes.
http://www.skepticalscience.com/A-detailed-look-at-Hansens-1988-projections.html
Not definitive, of course, but a pertinent example.
In order to verify Lacis’ claim that CO2 is driving Earth climate, I propose a small exercise regarding variations of CO2 concentration vs. variations of T° and PDO index, just using a convenient tool and data set available on the Net.
Proceeding
Step 1: go to woodfortrees site (http://www.woodfortrees.org)
Step 2: for each of the 3 parameters (HADCRUT3 variance-adjusted global mean / ESRL CO2 / JISAO PDO Index) apply following treatment:
a) From time… to time…. : select a ~ 20 or even 10 years period to get sufficient accuracy
b) Mean(Sample) => 12 (months) : to get rid of seasonal variations, especially for CO2
c) Derivative : provides the variations of the parameter w.r.t time
d) Mean(Sample) => 12 (months) : for “smoothing” the output signal
e) Normalize : to get comparable outputs’ scales.
Step 3: repeat the exercise using a 3 years (36 months) and a 11 or 13 years (132 or 156 months) averaging (here you can use the full [1958 – 2011] available data).
Results
[1970-1980]
[1974-1994]
[1990-2010]
3 years’ averaging
13 years’ averaging
Discussion
Main outcomes are the following:
1) All variations follow a similar pattern showing a roughly 3 years’ quasi-periodic cycle, likely to correspond to El Nino oscillation (ENSO)
2) [CO2] variations are following T° variations with about 6 to 12 months lag…
3) T° variations are generally following PDO index variations with a shorter lag (about 0 to 6 months)
4) By increasing the averaging time scale one remove “high frequency” cycles (i.e. ENSO) but put in evidence some larger scale cycles such as :
a) Solar cycle (11 years) using a 3 to 4 years averaging
b) PDO cycle (60 years) using a 13 years averaging.
5) Indeed, at any time scale you’re looking at this issue, the conclusion remains unchanged :
PDO variations are preceding T° ones, which are themselves preceding variations of [CO2]
Conclusions
1) Earth’ climate is not driven by CO2 concentration but by complex Oceans’ (thermal) Oscillations, Oceans’ being of course main heat reserve & inertia wheel of Earth climate system.
2) Variations of CO2 concentration are actually following these Oceans’ Oscillations and the subsequent ones of global temperature and of Ocean’s degasing rate.
3) IPCC claims that human use of fossil fuels causes global warming are not funded and formally falsified by comparison with observational data. AGW theory is fully based on flawed and formally invalidated models.
4) IPCC has promoted alarmist propaganda and dangerous policies, only based one this junk science.
5) NASA is losing money and credibility by supporting such dubious scientific claims.
So why these particular years?
Why not 1900 -2010?
or 1940 -2000?
Or is it important to choose the right years, otherwise the graph doesn’t support the point you are trying to make?
A long term correlation can be seen in:
http://farm4.static.flickr.com/3178/3079662254_175264ea6f.jpg
And yes, before someone says it, I do know that correlation doesn’t prove causation.
Does your graph have a source? It has no references whatsoever. Eric (above) was explicit about the data he used. Yours appears to have materialised from nowhere.
But I must admit that it is a very nice graphical demonstration that the observed (experimental) climate sensitivity (a al Arrehenius) is about 1.5–>1.6 since 1950. The graph gives you all the numbers you need to do the simple calculation yourself.
Thanks for the link.
Latimer Alder writes “But I must admit that it is a very nice graphical demonstration that the observed (experimental) climate sensitivity (a al Arrehenius) is about 1.5–>1.6 since 1950. The graph gives you all the numbers you need to do the simple calculation yourself.”
Surely this estimate of climate sensitivity assumes that all the observed rise in temperature is due to the increased level of CO2. So far as I am aware, this has not been established, so the value of 1.5 must be a maximum value.
Good point, Jim. And, if the figure is correct, it’s an ‘all forcings and all feedbacks’ maximum, at least for the period concerned.
You are calculating transient climate sensitivity, which is the immediate response of the system to forcing. IPCC gives the median value as 2.1C, with a range from 1.5 – 2.8C, from a doubling of atmospheric CO2.
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch9s9-6-2-3.html
This puts your calculations at the low end of TCR values, assuming you’ve got the numbers right.
Equilibrium climate sensitivity is the value most often referred to (3.2C) – the state the system arrives at once it has reached equilibrium with the forcing. A major process is thermal lag in the oceans – a process that takes about 30 – 40 years to equilibrate with forcing. I guess you could do a back of the envelope calculation taking CO2 data from 1950 to 1980, and temperature data from 1950 to 2010.Then you’re including ‘all feedbacks’ to get a more likely value for equilibrium climate sensitivity. Won’t be perfect by any means, but it will be better.
The temperature data is From Hadcrut 3. The CO2 data is from direct measurement from the 1950’s and from the ice core records prior to that. I probably should update the graph and I can send out this and the data on request.
Can you show your working for your ~1.5 deg C claim?
I hope you are considering all forcing factors and non-equilibrium effects in your calculations.
Tempterrain
Why these years ?
There is no dissimulation or brad trick in the choice.
For CO2 at Mauna Launa there is no record before 1959 that’s why I start in 1960, taking into account averaging constrains (there is a small error in my post : the 1rst curve corresponds to [1960 – 1980] and not to [1970 – 1980]).
Then I have divided the [1960 – 2010] period into 3 overlapping periods of 20 years each, just to provide a sufficient “zoom” and thus have a clear identification of the delays between the peaks or different valleys.
I could have started in 1910 but then without CO2.
Here’s the result
The link you have provided has no reference and the plot actually gives a very poor fit between CO2 and T° :
1) How do you explain that T° has decreased from 1980 to 1910 then from 1940 to 1970 while [CO2] was increasing ?
2) How do you explain that there has been no warming over the past 14 years whereas [CO2] has steadily increased ?
3) How do you explain that warming rate between 1910 and 1940 is exactly the same (0,15°C per decade) as the one observed between 1970 and 2000 whereas the rate of [CO2] increase was almost 3 times lower ?
For all these questions the answer is the same : [CO2] is just not the climate driver !
Eric
1) How do you explain that T° has decreased from 1980 [1880] to 1910 then from 1940 to 1970 while [CO2] was increasing ? [shown below]
http://bit.ly/bUZsBe
2) How do you explain that there has been no warming over the past 14 years whereas [CO2] has steadily increased ? [shown below]
http://bit.ly/ohGke8
3) How do you explain that warming rate between 1910 and 1940 is exactly the same (0,15°C per decade) as the one observed between 1970 and 2000 whereas the rate of [CO2] increase was almost 3 times lower ? [shown below]
http://bit.ly/eUXTX2
For all these questions the answer is the same : [CO2] is just not the climate driver !
Specially have a longer look at the following!
http://bit.ly/ohGke8
Many thanks Girma for illustrating so clearly my points.
Eric.
tt
Your “long term correlation” doesn’t even prove “correlation”.
Go back to Girma’s curves for a better picture, including the observed multi-decadal cycles of warming and slight cooling of roughly 30 years each, which you have totally ignored.
Max
Thanks Eric
PDO (labeled blue) => GMT (labeled red) => CO2 (labeled blue)
http://bit.ly/owlomP
Eric, please have a look at the above graph.
It appears that the increase in CO2 concentration is due to increase in the GMT, not the other way round.
I understand Steven Mosher’s point about models often being the only tool for some kinds of scientific investigations. However that doesn’t mean they’re any good. I keep recollecting that Father Ted episode “Speed 3” where the titular character opted to celebrate Mass as a way of rescuing his friend, stuck driving a booby-trapped milk float.
Of course the Mass wasn’t any good at solving the situation but Father Ted could have argued it was his only available “tool” to do something at the time. Likewise for unpredictive climate models.
Thanks, omnologos. Why is not this obvious to the proponents of CAGW?
Maybe they don’t watch “Father Ted” ?
I watch Father Ted :)
But you’re not exactly a proponent of (C)AGW ;-)
It’s encouraging to see that several denizens of this thread are aware that the distinction between thermodynamic equilibria and steady-states is more than semantic. Fundamental climate questions of interest here involve thermal energy transport and temperature – if that’s not thermodynamics, give me a better word. The defining thermodynamic feature of the steady-state is a linear increase in entropy with time and a linear decrease of free energy with time. The latter is called dissipation, The steady-state requires a constant input of energy or matter to persist – perpetual motion devices excepted.
Thermal transport is a dissipative process. The simplest possible conceptual experiment is what’s the dissipation from a thermal flux of X watts in a cell with a temperature differential of Y degrees? (I didn’t find the answer on Wikipedia.) High-school thermodynamics, aka watts=volts*amps, offers a hint. This is really a most under-appreciated expression. It is an exact solution for dissipation from electric currents in a steady-state no matter the system’s linearity. It is valid whether conduction be due to electrons, holes, cations or anions or some horrendous combination thereof. Let’s consider a hypothetical prototype for the troposphere – we’ll call it an electric convection oven. With slight modification we put it in a vacuum chamber with 4K walls and surround it with a web of radiometers to measure its thermal emissions. Would anyone doubt that, when a steady-state is reached, radiometric integrations would not agree with voltammetric measurements, instead also depending on undefined complexities of the internal fluxes of radiative and convective transport? I’ll assert there exists an equally simple phenomenological relationship relating thermal energy flux and temperature as with electric currents and potential.
Can the troposphere be usefully described by steady-state thermodynamics? A fair question, but the parameters under vociferous discussion, i.e. forcings, feedbacks, etc., are themselves steady-state descriptors. In any case, I believe there’s a lot more to be learned from steady-state thermodynamics than climate science rhetoric.
“Fundamental climate questions of interest here involve thermal energy transport and temperature – if that’s not thermodynamics, give me a better word.”
Phenomenology
“Can the troposphere be usefully described by steady-state thermodynamics? A fair question, but the parameters under vociferous discussion, i.e. forcings, feedbacks, etc., are themselves steady-state descriptors. In any case, I believe there’s a lot more to be learned from steady-state thermodynamics than climate science rhetoric.”
Old school thermo 101! KISS, frame of reference, never ASSUME. Sometimes a cellulose screen with a graphite interface is the best modelling tool
As I understand the concepts, it cannot, because convection and transport of latent energy are essential, but they are not a described by thermodynamics, but rather by fluid dynamics, which is in many ways a different field of physics. The fields are of course related in many ways, but no specific name has been given to science that covers both as evidenced by the fact that we still have, e.g. ICFDT 2012 : International Conference on Fluid Dynamics and Thermodynamics in Zurich.
hip hip
Gases still expand with heat transfer. contact>conduction>expansion>lapse rate. Small but it would exist. If radiant transfer were perfect, no tropopause, no surface temperature. Nothing is perfect.
Pekka,
If Hawking finds thermodynamics useful for understanding black-hole dissipation, I reckon it’s worth a try at understanding the local equivalent. My personal definition: when entropy is created, thermodynamics is in play. It rarely provides complete solutions, but sets conditions to be met by a true solution. Electric analogies are important guidelines wrt dissipation. Given so many volts and so many amperes for a steady-state, I know, with high confidence, a circuit’s dissipation. I haven’t a clue as to the internal distributions of potential and flux. Can’t even tell what the flux is physically – ions, electrons … By definition, climate sensitivity is a change in dissipation wrt temperature (or its reciprocal), and prudence suggests careful consideration of what limits might be imposed by thermodynamics. By my own calculation, a 2% change in dissipation corresponds to a maximum temperature change of 1.6K, assuming that flux is non-divergent and that its temperature coefficient is => 0. I have no clue as to what makes up this flux, although its magnitude is of order 1Kw/m2.
Anyone with a P&P calculator should be able to derive the sensitivity, dW/dE, for a circuit where J is proportional to an arbitrary power of E and see how the game is played.
quondam,
There’s no doubt that thermodynamics is essential for understanding the atmosphere, I didn’t argue about that. What I said, is that thermodynamics alone is not sufficient at all, but we need also fluid dynamics.
The dissipation is totally in the fluid dynamics part of the problem. Thermodynamics alone cannot describe it at all, but it may be possible to pick the rate of dissipation and a few other things from fluid dynamics and use thermodynamics for much of the rest.
The electrical analogy is unlikely to work well, because convection is collective motion, while the analogy with electrical circuits may be easily applied only to heat conduction and part of the radiative heat transfer, but no to the collective conduction and latent heat transport.
It is becoming increasingly clear that historically CO2 has been the “big control knob” as Richard Alley puts it.
What I have difficulty with is the analogy between paleoclimate and the present situation that some climate scientists seem to love making. Forty years ago CO2 was climbing at quarter of a percent per year, currently it’s climbing at half a percent. At that rate it’ll be climbing at one percent a year by 2050.
For comparison CO2 took a huge dive from 3500 ppmv to 650 ppmv 49 million years ago, freezing over the previously open Arctic Ocean. There were no humans back then, and supposedly the CO2 knob was turned by an enterprising seafarer, the Azolla fern, albeit in the opposite direction to ours.
Our jump from 280 to 390 ppmv pales into insignificance by comparison until one takes into account that whereas the Azolla project took 800,000 years, so far we’ve only been working on reversing their effort for a century or so, with most of the work accomplished in the last half century. Moreover estimates of peak oil and coal are naively predicated on 20th-century technologies, which demand will surely ramp up to extract 10-30 times the total combustible carbon we’ve consumed over the past millennium assuming continued dependence on carbon based fuels. Contrary to some optimists the end is nowhere near in sight.
The problem with the paleoclimate analogy is that the CO2 knob was previously always turned very slowly by comparison with modern rates. At today’s rate the heat from the atmosphere is accumulating too fast to drain into the land, and only the oceans are able to convect it away from the surface.
What people seem not to appreciate is that the heat capacity of the oceans is limited to that of 1.3 cubic megameters of water. Averaged over the 510 square megameters of Earth’s surface, that comes to a mere 1.3/510 = .00255 megameters or 2.55 km of depth. From here to the center of the Earth is 2500 times that much! Any difference between the specific heat of water and the Earth’s crust pales into insignificance when comparing their respective heat capacities.
The heat capacity of the ocean is only of interest when CO2 is rising too quickly for the land to absorb it. That’s true today, but it was not true at any previous time in the history of the Earth, when the heat capacity of the land was more than adequate to absorb the heat.
That’s not to say that CO2 didn’t heat the planet. It most certainly did, but not along the curve we’re seeing today. When you add CO2 gradually you keep the planet relatively close to thermal equilibrium at all times, with the gap between absorbed solar radiation ASR and outgoing longwave radiation OLR on the order of milliwatts per square meter. When you increase it at half a percent per year you widen that gap to something like a watt per square meter, with an associated top-of-atmosphere temperature gap of a quarter of a degree, huge compared to anything seen historically, and then the rapid quenching provided by the ocean kicks in to drive surface temperature along a very different curve from those followed millions of years ago at such CO2-changing events.
We are in a unique situation today which makes paleoclimate irrelevant for such purposes as predicting CO2 residence time or inferring modern climate sensitivity. The estimates of those parameters made by the likes of David Archer and Gavin Schmidt on the basis of paleoclimate simply do not hold up under examination.
Dr. Pratt,
I often disagree with you, but I have found that you typically tell it like you see it.
So I have two questions:
In your extensive experience can you pleasestell us when anyone has ever described something that has historically responded after that which it allegedly controls as a ‘control knob’?
Also, there appears to be some confusion over the way ‘logarithmic’ is applied irt CO2.
Can you please, based on your knowledge, please clarify if, as some claim, CO2’s impact increases logarithmically, or if it decreases logarithmically?
For your first question, hunter, I hope you won’t mind if I pass that buck to someone who is the polar opposite of me, namely a church-going registered Republican with more years of experience in paleoclimate than I have weeks. (I’m not even registered.) You can see him answer your question at mind-numbing length in (a link you may well have run across before) the video at http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
If you have questions about any of the many particular instances of evidence he offers in answer to your question above I’d be happy to try and answer them, although I suspect there will be others here better qualified to do so.
I believe I can answer your other question as well as anyone, since the answer is based on the physics I was taught as an undergraduate in the early 1960s, which fortunately I still remember well. The answer can be found in the HITRAN absorption and emission line spectra table for the first species of CO2, namely ¹²C¹⁶O₂.
98% of Earth’s radiation is in a range containing some 32,000 lines of that species. Several hundred of these are currently totally opaque to photons attempting to pass straight from the Earth’s surface to space. A few more hundred are in transition and becoming more opaque with increasing CO2 level. The remaining 31,000 or so are transparent and likely to remain so for the foreseeable future.
Examination of the lines currently in transition shows that they are gradually closing at a combined rate such that the logarithmic law is an excellent approximation. After a couple hundred more have closed, say by the year 3000 assuming business as usual, the law will not be followed quite so accurately, with the error unfortunately being in the direction of increasing surface temperature per doubling of CO2.
More detailed figures on request.
Vaughan – I find your argument about heat capacity interesting, but I’m not sure I completely understand it. If you draw a line, A, from the top of the ocean to the center of the Earth, and another, B, from a land site to the same center, A and B will be approximately equal. The main difference is that the top part of the trajectory in A will be water rather than land in the case of B. It’s certainly my understanding that the heat capacity of water is considerably greater than the heat capacity of dirt (it’s a major factor in wind generation from land/ocean differences). Once we get below the ocean bottom, the heat capacities shouldn’t differ much between A and B, but I’m not sure that’s relevant. I believe rock is such a good insulator that most of the Earth’s crust is essentially shielded from the climate as though the crust below the rock didn’t exist. In other words, when land is heated, the heat accumulates down to a relatively shallow depth and stops there, because a deep layer of rock can maintain a temperature difference almost indefinitely.
If you have contrary evidence, I would be interested in it. It does seem, though, that at timescales of at least many thousands of years, ocean heat capacity dominates land heat capacity, and perhaps for far longer. I don’t know of good data on this, though, so if you have some, I hope you’ll direct us to it.
Fred,
I think this discussion of boreholes may help:
http://www.geo.lsa.umich.edu/climate/approach.html
Bill
Thanks, Bill. The diagram doesn’t specify depths, but it’s my understanding that only half a kilometer may take a thousand years or so to register a temperature effect due to the poor conductivity of the material. Once we get to several kilometers (e.g., below the ocean bottom), the time is likely to be very long while at the same time storing relatively little heat because of low heat capacity vis-a-vis the ocean. The latter also distributes heat via convection, which is more efficient than conduction, and permits heat to be mixed downward to make room for more heat at the surface.
I believe rock is such a good insulator that most of the Earth’s crust is essentially shielded from the climate as though the crust below the rock didn’t exist.
Well, that’s certainly not true. The current upwards heat flux through the crust is 65 mW/m2 on land and 110 mW/m2 through the crust below the ocean (since the geothermal gradient is larger there by virtue of the ocean bottom being colder than at the corresponding depth on land).
That 0.1 W/m2 flux is presently being swamped by the TOA global warming flux of 0.9 mW/m2 caused by the half-percent/year rate of CO2 increase. There is no way that ten times the heat can flow down that is currently flowing up without ten times the temperature gradient, which would require a surface hotter than Venus.
But CO2 need only increase at one-hundredth of that rate in order to have a noticeable impact on the geologic record over a 10 ky period, and the corresponding global warming rate at TOA would then be only 10 mW/m2. (The Azolla event took 800 ky, which viewed from 49 million years later seems a short period.) The upwards 110 mW/m2 through the crust below the ocean only has to drop to 100 mW/m2 upwards in order to soak up 10 mW/m2 of global warming at TOA, which an extra 5 or 10 °C at the ocean bottom would accomplish.
Your image of the crust as an essentially perfect thermal insulator is based on an unwarranted extrapolation of what today is a pretty accurate approximation, but only to within 10%. Two orders of magnitude less global warming and that 10% inaccuracy climbs to a 1000% inaccuracy.
the TOA global warming flux of 0.9 mW/m2
Should have been 0.9 W/m2. (I changed 900 to 0.9 but forgot to change mW to W.)
Vaughan – the article you linked to appears to convey a different impression:
“Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust.[12] This is approximately 1/10 watt/square meter on average, (about 1/10,000 of solar irradiation,) but is much more concentrated in areas where thermal energy is transported toward the crust by convection such as along mid-ocean ridges and mantle plumes.[13] The Earth’s crust effectively acts as a thick insulating blanket which must be pierced by fluid conduits (of magma, water or other) in order to release the heat underneath.”
This seems to confirm my previous understanding that the crustal materials are very good insulators (not “essentially perfect insulators”) and permit modest heat flows only in the face of very strong temperature gradients – much stronger than would occur from the climate system down, I think it therefore supports the notion that heat from the climate system runs into a strong insulating barrier within the crust. Combined with the lower heat capacity of the terrestrial materials compared with the ocean, it is consistent with the observational data that land heats and cools more rapidly than the oceans because the land has less effective storage capacity over timescales of at least many thousands of years. With much longer timescales of continued unidirectional heat gain or loss, the difference might disappear, but the climate record doesn’t suggest that kind of uninterrupted trend during most past intervals as far as I know.
What’s essential is that the heat flow through the crust is affected very little by any conceivable change in surface or ocean temperature. It’s a background process that’s controlled by geology. For all climate related phenomena it’s a weak additional heat flow that may sometimes vary strongly on local level due to volcanic events.
The seasonal variability is observable only in the top few meters, and deeper crust has very little role in climate variation except that some more significant effects may result from changes in ground water level and in the extent of permafrost.
The average heat flow directly yields the average thermal conductivity. Its homogeneity or lack thereof does not bear on the average.
The seasonal variability is observable only in the top few meters, and deeper crust has very little role in climate variation except that some more significant effects may result from changes in ground water level and in the extent of permafrost.
Quite right. So what do you infer from those numbers concerning variability with a period greater than one year? For example at what depth would you conclude that a temperature change that took 10 ky, or 90 ky, would be observable?
May main conclusion is that the average flux calculated over periods of several years or longer depends so little on the surface temperature that it has no significance on the climate. A persistent change in surface temperature will ultimately affect the crust to significant depths, but based on flux variations that are really small in comparison with other flux variations.
Vaughan, Pekka
The flux in and out of the crust is neglibable on a time scale of the surface mixing layer. The 4C maximum desity layer of the ocean is a barrier to thermal flux. the temperature below that 4C at the depths is a separate energy balance between the 4C barrier and the core.
A little more detail
http://ourhydrogeneconomy.blogspot.com/2011/10/what-is-4c-thermal-boundary.html
Dallas, your 4C barrier can only accommodate a 4C variation in ocean temperature before the barrier evaporates. During each 100,000 year cycle over the past million years the surface temperature variation has been 10C. This completely blows away your barrier and any argument based on it.
Dr. Pratt: Fascinating post. The azolla event is well worth reading about.
I take your point that we are in uncharted waters as far as the rate at which CO2 levels are rising, though I don’t blame climate scientists for looking to paleo times as guides to our times.
What are the repercussions of your “rapid quenching” scenario?
What are the repercussions of your “rapid quenching” scenario?
That the temperature will only rise 2-4 °C over the next century instead of 10 °C or more. The rapid rise in CO2 needs the rapid quenching from the ocean to avoid a truly drastic outcome. Normally I’m Alfred E. Neuman when it comes to worrying about the impacts, which I’m happy to leave to others, but if there were no ocean to quickly soak up that heat, even I could learn to worry.
If however methane release from the melting tundra gets out of hand, it might not be that different from having no ocean to keep things cool. No one has a good idea of how that scenario is going to play out over the next couple of decades, but in principle it could turn real nasty. It’s like driving around a bend in a seemingly empty country road at 90 mph on the assumption that there isn’t a semitrailer overtaking a little car coming the other way. That assumption almost always worked out for me when driving in the Australian outback in the sixties, only ever encountered that situation once. It was very interesting.
“If however methane release from the melting tundra gets out of hand, it might not be that different from having no ocean to keep things cool. ”
As we seen with arctic sea ice, it might reduce to lowest ice coverage in 2007 but instead runaway it doesn’t. We have climatic cycles which are more significant than yearly increases in global warming. The last 160 years of warming have not had any dire consequences, there is little reason to assume dire consequences in next 100 years:
Global methane:
April 23, 2008
“Last year alone global levels of atmospheric carbon dioxide, the primary driver of global climate change, increased by 0.6 percent, or 19 billion tons. Additionally methane rose by 27 million tons after nearly a decade with little or no increase. ”
http://www.noaanews.noaa.gov/stories2008/20080423_methane.html
~160 years of warming.
I am not sure how accurate JCH graph is but it indicates about 100 years of warming prior to 1950. One see the cyclic variation and peaking temperature around 1940, the cooling trend which follows this
[related to New Ice Age scare which followed this], then temperature recover by early 1980’s giving warming trend almost as significant as the period from 1900 to 1950.
JCH, your graph shows only a .5 to 1 degree increase Celsius by 2100.
That the temperature will only rise 2-4 °C over the next century instead of 10 °C or more.
Is this what got you busted on that orthodox blog?
If however methane release from the melting tundra gets out of hand…
Stewart Brand describes this possibility in rather horrific detail in “Whole Earth Discipline: An Ecopragmatist Manifesto.”
James Lovelock believes we will return to an equilibrium point similar to the Paleocene–Eocene Thermal Maximum in which the poles were ice-free. Most of the human race will die in the process, he claims and he doesn’t believe much can be done about it at this point.
huxley,
Brand and Lovelock are writing science myth, not even science fiction.
hunter: How do you know? If one is persuaded that CO2 is the “principle control knob governing earth’s temperature,” then doubling CO2 in a couple of centuries — an eye blink of geological time — must have noticeable, perhaps even disastrous, effects.
Brand outlines this is as a possibility, unlikely but still worth study and factoring into policy decisions. Brand takes climate change seriously enough that he reversed his long-held opposition to nuclear power. Brand has been publicly encouraging environmentalists to examine their biases against nukes, overpopulation, cities and genetic engineering.
Lovelock is known for his Gaia Hypothesis that life on earth essentially regulates planetary conditions through deeply interconnected feedback loops so that planet remains hospitable to life. If CO2 is so important, then it’s not hard to see how Lovelock would conclude that increasing CO2 rapidly would tip the planet into a hotter equilibrium. Of course, that doesn’t make it true and his last book was more of a polemic than a closely reasoned exposition.
My concern with Brand and Lovelock is that they are predisposed to see the planet as more fragile than it is — judging by the eco-apocalypticism they embraced decades ago which failed to emerge. However, in the longer run I can’t say I know they are wrong.
huxley,
Gaia has survived the proto-lunar collision, apparently large numbers of other, smaller, impacts, super volcanos, probably a “complete” ice over, plate tectonics, a transformation from a CO2 atmosphere to a high O2 atmosphere, disease, mega droughts, ice ages, etc. etc. etc.
You are absolutely correct: Earth and life on Earth are both tough.
As for the runaway tipping points, if it was going to happen it would have.
According to the accepted record, there are multiple instances of much more dramatic temperature changes than we are seeing, or are likely to see.
We muddled through OK.
Frankly the idea that we are to implement policies today that are known to be objective failures- which each and every AGW CO2 policy demand is when viewed objectively- to stave off a predicted crisis in >50 years that is based on what is clearly unclear and incomplete knoweldge and analysis is really a waste of time treasure and talent.
hunter: I’m not arguing for Brand’s and Lovelock’s cases. I’m saying that they are not writing “science myth” as you claimed.
They are making honest, scientific arguments that the current climate could change drastically — as it has in the past — and such a change wouldn’t kill off humans or the earth, but would seriously disrupt civilization. I see nothing “mythical” about that.
huxley,
Thanks for the clraification.
When I read Lovelock’s conjecture about moving to Antarctic, it reminded me of a cheesy SF novel I read many years ago where the remnants of humanity were holed up in Antarctica and found out that their technological approach to survival was inimical to the psch powers most inhabitants of the galaxy relied on.
hunter: “The Three Stigmata of Palmer Eldritch” by Philip K. Dick has the rich people living in Antarctica because of global warming. But it turned into a “What is a reality?” exploration after a powerful psychedelic drug from aliens is delivered to earth. One of Dick’s best and most bizarre, which is saying something.
huxley,
Somehow I missed that one from the late great Philip A Dick.
I will make certain to get it and read it sooner than later.
SF can be such a great genre for exploring human interactions with technology, the unknown and ourselves.
Dick, even in his most parnoid, was able to tell great stories that consistently challenge your preconeptions and assumptions and leave you looking at things differently.
hunter: If you like PKD that much, you won’t be disappointed in Stigmata. I went on a jag and read just about all of his work in the Eighties and he just about ruined SF for me. Next to PKD most SF is cheesy franchise stuff.
To connect back to climate, PKD did read science and he knew that global warming was a future possibility, so he put it into that book.
I go on a PKD excursion every decade or so, but I obviously miss some scenic spots, so to speak.
As to the AGW scenarios, I just see them as standard plot tools, like the over use of retired nazi bad guys living in or sneaking out of SouthAmerica in the 1980’s.
Benford has written some serious scenarios on cryo-arks to preserve genotype information for a future day when humanity is up to the task of major remediation and restoration, and in his great Galactic Center series, he uses an Earth suffering from eco and climate issues, but story tellers use apocalypse- especially apocalypse caused by human wickedness- throughtout histroy going back to at least the flood stories of the Bible and other traditional narratives.
I am more of the ‘we will muddle through’ and like to point out that in any objective measure, human’s condition and the environment are actually improving in many ways. Longevity, health care, food security, education, wealth (even in today’s sad economy) are improving .
In the environment, more of the Earth is being placed into protection than ever, and an ethic towards protecting wild spaces and restoring them is growing.
I jsut happen to think that CO2 obsession is actually slowing down the good and increasing the bad by its focus on one aspect of climate at the expense of many other very important factors, and obsessing on this one factor by means of policies and technologies that literally do not accomplish what they are claimed to be for.
Also, teh CO2 obsession is attracting some very misanthropic people who seek to literally destroy civnilation in the name of some sort of authentic environmental ethic that is in reality a whole lot like xenocidal madness.
me: That the temperature will only rise 2-4 °C over the next century instead of 10 °C or more.
huxley: Is this what got you busted on that orthodox blog?
Busted by Foster. ;) No, that was for pointing out that 98% of the long-term variance in the global temperature since 1850 consisted of the global warming signal together with two strong low frequency (50-60-year and 70-80-year period) components correlated with ocean oscillations. (I’ve since been able to attribute most of the remaining 2% unexplained variance to leakage of irrelevant high-frequency components due to a bad filter.)
Ironically I was shot down by Tamino a month before I’d ever even heard of him or his (ironically named) blog Open Mind. Someone had drawn his attention to my demonstration of the correlation on a different site. He dismissed it on his blog with the statement, “You can’t just take the deviations from a 65-year smooth and call them the ‘effect of the AMO.’ First, such fluctuations in AMO are the result of the global warming forcing, not the cause of it. Second, to believe that deviations in global temperature on 65-year time scales are somehow the ‘effect of AMO,’ you have to suppose that they are *not* due to an early-20th-century lull in volcanism, early-20th-century increase in solar activity, and huge mid-century increases in anthropogenic sulfate aerosols. But in fact they *are*.”
When my attention was drawn to Tamino’s comment a month later, I signed up for the blog and posted this disclaimer to the effect that nowhere had I claimed that the deviations were the effect of the AMO but merely that they were correlated with it.
In his younger days Tamino worked on statistics of variable stars, but his transition to the blogosphere would appear to have erased whatever he once knew about the difference between correlation and causation. Ignoring my disclaimer, he insisted I had “fallen into a trap,” concluding with “I think your theories have no merit. I respect your civility. But no, I don’t wish to argue with you about it.”
So I pointed out that “I came to this website when it was drawn to my attention that people were criticizing me behind my back for reasons I could not discern.” To which Tamino replied “You start by accusing me of criticizing you ‘behind your back’ as though I were whispering in the hallway to some school chum, trying to conceal what I was saying. This is wrong, offensive, and frankly, rather childish. Then you play the part of the wou nded, when I only criticized your ideas (and with very good reason) but you are the one who’s decided to make it personal. Your silly remark about ‘uncivil welcome’ and ‘not how science is normally conducted’ completes your delusion of martyrdom.”
Apparently there were not just one but two words I didn’t say that he thought he heard, “cause” and “jerk.” The two words that came to my own mind were “deaf” and “angry,” which seem apt for a great many participants on both sides of the climate debate.
He concluded with “If you think your model is so good, publish it in the peer-reviewed literature.” So I submitted it to the annual American Geophysical Union meeting under the title “A three-component analytic model of long-term climate change” and it was accepted for presentation. I’m guessing he was not one of the referees.
Dr. Pratt: Thanks for the response! Congrats on getting a presentation.
Smaler scale of course, but many, many situations. Consider the control knob of detergent phosphates entering the environment in the last century. The accelerated eutrophication of thousands of lakes were essentially halted once everyone stopped dumping the detergent directly into the water (via processing ponds) or by reducing the levels of phosphate in detergents. Success.
Web,
So eutrification normalized before the phosphates were halted?
Amazing.
I don’t know what you are talking about. I did say that wastewater treatment was involved, which is a control knob of avoiding having the phosphates go directly in the water.
How about the control knob of CFCs against ozone?
Lots more examples in store. You just don’t like to hear about them.
WHT,
I appreciate that if you clean stuff up, and reduce the phosphates it damages the water less.
Your examples are not equivalent or relevant to the CO2 being a control knob, however.
They would only work if the water got polluted prior to the phosphates and cleaned up before they were removed.
WHT – huh? and huh?
While I don’t quite get the wording of hunter’s 3:53, there’s no paleoclimate record showing past eutrophication produced phosphates, or that naturally depleting ozone generated CFCs. So I think your analogies are not analogies.
If in the past CO2 lagged temperature, it wasn’t acting as a control knob at least in the initial temperature rise.
Bill C-
Lacis claims CO2 is a thermostat to drive temperature up.
I point out that in every situation I am aware of, you first increase the thermostat and then the temperature goes up.
The historical record, based on widely accepted ice cores, suggests strongly that temperatures increase for hundreds of years prior to CO2 increases.
If CO2 is a thermostat, then the record should show evidence that goes 1- CO2 increase; 2-Temperature increase.
Instead, it is the opposite:
1- temps increase; 2- CO2 increases.
If anyone has a thermostat that goes up after the temps go up, please do share.
Then I am lost as to what hunter is railing about. Doesn’t matter and the vast majority on this blog doesn’t care about this stuff anyways.
WebHubTelescope
To hunter’s statement:
you responded:
It appears to me that hunter was simply drawing attention to the 450,000 year ice core data, which shows that CO2 changes lagged temperature changes by several hundred years (effectively refuting Al Gore’s AIT cause/effect rationalization).
Although Dr. Richard Alley likes to skirt around this dilemma by diverting to his credit card debt and interest, it remains an “unsolved mystery” for those who “believe” that “CO2 is the control knob”.
Max
Sorry, I see it was the statement of BillC, not hunter…
manacker,
I watched Dr. Alley last night on this topic, and will watch him again today. Dr. Pratt says Alley is a Republican and Christian. As a fellow Republican and Christian, I think I recognize arm waving when I see it.
My first impression is that Alley is arm waving.
Anyone who jumps straight into the strawman of using a grand conspiracy on either side of this loses my credulity.
No need for me to watch Alley.
The “consensus” theory (as per RC, if there is such a thing) is that something else (orbital/solar forcing) caused temp to start rising, which caused CO2 to start rising, with massive temp feedback effects. The claim is that now it goes the other way due to the rapidity of the CO2 rise and the fact that if the current CO2 rise is anthropogenic, then it wasn’t temperature precipitated.
I agree with Hunter that the control knob analogy fails here, but even if you could get Alley to agree with this after a few beers, it wouldn’t change the argument, just the semantics of it.
BillC,
that is the problem with Alley’s very nice presentation:
It boils down to “and something wonderful happened” to explain the lag.
And that does not fix the problem, in reality, because it is clear that the reality is that nothing dangerous or unusual happened in response to the CO2 increase, and that temps actually go down AFTER the CO2 went up, over time.
This is like the stage of evolutionary science when teh eugenics folks knew that ‘breeding’ was the control knob for good evolutionary management and the social results they were after:
Yes, they were on to something (look at dogs, look at plant hybridization, etc.) but the application they were after, a glorious society of healthy wonderful caucasians, was bogus.
Climate science / AGW social movement takes the physics of CO2 and demands we build a society in the world that just happens to look like the society most of the AGW believers happen to want, using technologies they happen to like.
Look at Australia’s carbon tax: it will literally do nothing at all to lower the Earth’s CO2. It will hurt Australians. It will not stop one cyclone, it will not end one drought. It will not change the rainfall.
But it will cost.
I just did this Vostok cross-correlation myself, and it’s kind of tricky with the data available, but yes, the lag between CO2 and Temperature is there:
http://theoilconundrum.blogspot.com/2011/10/vostok-ice-cores.html
http://1.bp.blogspot.com/-OKesbsAmk28/TphIFVVfhbI/AAAAAAAAAkI/yHIzAXQBvzo/s1600/vostok_crosscorr.gif
This is a positive feedback situation, increased temperature leads to increased atmospheric CO2 concentration due to ocean outgassing, which leads to further GHG effect and further warming. Once it gets going its a reinforcing behavior and so there you go.
The historical record, based on widely accepted ice cores, suggests strongly that temperatures increase for hundreds of years prior to CO2 increases.
To raise temperature is divine, to raise CO2 human.
Yet nature seems to be divine, albeit in a different order.
“Mother Nature” is a “mutha”
Indeed. At a certain age however the roles reverse and one must look after one’s mother.
lol- very insightful.
Yes, if people live long enough we get to do for our parents as they did for us as children.
As for the larger mutha, we have muddled through pretty well and are getting better at it.
As for the larger mutha, we have muddled through pretty well and are getting better at it.
This disagreement is common in families. As the rationale for not having to care for an ailing mother one offspring will declare her hale and hearty, leaving the other offspring to look after her in her old age.
Momma’s doin’ jes’ fine, Vaughan.
Max
We already knew you were that offspring, Max, no need to remind us.
Let me go back some way in discussing cliamte sensitivity. The problem arises almost directly from Andy Lacis’ contention that
“Fortunately, the global warming component, it being tied directly to the growing strength of the terrestrial greenhouse effect, is a uniquely radiative effect that can be addressed independently of the other climate complexities”
So far as I am aware, this is merely an assumption which has never been established by fundamental physics. I have seen this sort of thing many times in my career, where someone makes a guess, This is then referenced several times, by which time the guess has become gospel truth. Only by going back to where the guess started can one see that it was merely a guess.
The reason the warmists need to make this assumption, is that if they dont, then climate sensitivity is a function of conduction, convection and the latent heat of water. And in which case it is impossible with current knowledge to put any quantitative value on how much adding more CO2 to the atmosphere increases surface temperatures.
The Lacis assumption leads to the abomination of no-feed back climate sensitivity, which, so far as I can see, is a purely hypothetical number which has no place in real physics. However, it is now so firmly embedded in the literature that it is almost impossible to eradicate. Once you have no-feedback climate sensitivity, one can add the feedbacks, and arrive at CAGW.
Now others, like Roy Spencer, are looking at the actual data, to see how it compares with the warmists ideas. In Roy’s case he is lookig at the ERBE anbd CERES satellite date, and concludes that CAGW is wrong. What we are doing here is looking at the temperature data , and seeing whether we can detect a CO2 signal. Now there are clearly natural variations, and what the warmists assume is that their contributiion is negliglble because they are the equiavalent of random noise. This is only true is the integration time is long compared with the time constant of the natural variations. Now we have no idea what all the natural variations are, nor do we know their amplitudes or time constants
However, what we are saying is that even if you make the most generous assumptions from the warmist point of view, then the actual temperature data does not show any appreciable CO2 signal. One cannot support a number as large as 1C for a doubling of CO2 for total climate sensitivity Anyone can obfuscate about what specific climate sensitivity we are estimating, but it does not make any difference. There is no CO2 signal that is discernable in the temperaturee data.
In the complete absence of all other damping or amplifying mechanisms, it seems that a tiny increase in T would lead to a T->CO2->T->CO2…. feedback loop that would cause runaway GW, whereas a tiny increase in CO2 would lead to a CO2->T->CO2->T….feedback loop that would cause runaway GW. Until the T and CO2 feedbacks got “saturated” by whatever mechanism. No one is claiming this, but some of you are claiming that the CO2->T link does not exists, whereas it seems most warmists downplay the T->CO2 link. Having both (if true) makes this a sort of logic puzzle not a scientifically deterministic cause->effect relation of the kind we are used to seeing in physical science. Which came first, chicken or egg? Show me a scientific answer that doesn’t invoke much more complicated processes to explain it, like the existence of a Creator or evolution. I agree with Dallas that WHT seems to have a pretty good handle on aspects of it, though I prefer WHT to Webby. Regarding the original WHT:
http://www.myspace.com/blogurt/music/songs/wht-live-on-the-force-15374169
Yes. I see no reason that CO2 can’t function as a lagging indicator of temperature change as well as a causal agent of temperature change.
huxley,
If it is also a leading forcing, then please explain why when CO2 goes up in the historical record temps do not go up a lot more.
The positive feedback of outgassing is strong until it hits the diminishing return of CO2 as a GHG. That’s why I think it always clamps at 290 to 300 PPM coming out of previous ice ages. One of the interesting features of positive feedback is the “rail-to-rail” phenomena, with the signal having an inertial propensity to go toward the rail in which it has been nudged.
Hunter, which historical record are you referring to? Less than a million years ago, more than 500 million, somewhere in between?
It’s not like the historical record has been boringly repetitive.
Jim –
The greenhouse effect is real physics. Having an atmosphere containing an LW absorbing gas like CO2 will keep the surface temperature of the planet warmer than it would be if the surface temperature is heating only by the solar radiation that it absorbs.
For Mars and Venus the LW absorbing gas is primarily CO2. On Earth there is also water vapor available that can amplify the greenhouse heating by CO2.
We derived (fitted) an algebraic formula in 1988 that gives the CO2 (no-feedback) greenhouse heating.
ΔTo(x – xo) = f(x) – f(xo)
where
f(x) = log [ 1 + 1.2 x + 0.005 x^2 + 0.0000014 x^3 ]
This formula is basically similar to the standard log (x/xo) that you see frequently used, except that the formula we derived works for CO2 amounts starting with zero.
For example, plugging in x = 600 ppm, and xo = 300 ppm, yields ΔTo(x – xo) = 1.21 K for the no-feedback doubled CO2 equilibrium temperature change, or the CO2 greenhouse temperature response. Multiplying 1.21 K by the conversion factor 3.3 yields 3.99 W/m2 for the doubled CO2 radiative forcing sensitivity.
There are no ‘assumptions’ here. This is all very basic fundamental classical physics that has been understood for more than a century. It is a straight radiative transfer physics result calculated for the temperature (and solar absorption) structure of the Earth. Similar formulas could be derived for Mars and Venus. Since those atmospheres are primarily CO2, such formulas would give the equilibrium surface temperature for different CO2 amounts on those planets.
For the Earth, there is water vapor available. The amount of water vapor that the atmosphere can hold is temperature dependent (the Clausius-Clapeyron relation). The CO2 greenhouse effect provides the sustaining temperature for the atmospheric water vapor. The water vapor will raise the surface/atmospheric temperature, and additional water vapor will be supported in the atmosphere. But only up to a limit, any water vapor exceeding that limit will condense and precipitate. (There is no run-away water vapor feedback.)
That is the nature of the terrestrial greenhouse effect. You have CO2 (and the other non-condensing greenhouse gases) provide the sustaining temperature structure. Water vapor (and clouds) provide amplification of the non-condensing gas greenhouse effect. If you take away the non-condensing greenhouse gases, water vapor will condense and precipitate, and you will be left without a greenhouse effect.
Andy, given that water vapor is itself a GHG, why cannot it sustain itself up to some limit?
Andy, given that water vapor is itself a GHG, why cannot it sustain itself up to some limit?
David, are you joking or what? After all this discussion about water vapor being the only condensing GHG, how can you ask a question like that?
Dr Lacis,
Please see my post below.
http://judithcurry.com/2011/10/11/co2-control-knob-discussion-thread/#comment-121957
Dr.Lacis,
I would submit that if you had posted justwhat ou have posted here at the start, a lot more light and a lot less heat would have been resulted on this thread.
Thank you for your reply.
Andy – In Figure 2 of your paper, zeroing out the noncondensing GHGs results in water vapor asymptoting toward about 10% of existing levels, with cloud cover increasing slightly. Unless this changes at much longer intervals, I assume there is a small residual LW absorption. Planetary albedo increases, and these two effects would tend to cancel out, but whether there is no net effect is unclear. Is it fair to say that removal of the non-condensing gases would change the climate in a manner equivalent to a climate without a greenhouse effect, but that the actual greenhouse mechanism would still be operating at a low level?
Thank you for your reply, Andy, but I am still not convinced. The formula you quote, namely
“f(x) = log [ 1 + 1.2 x + 0.005 x^2 + 0.0000014 x^3 ]
This formula is basically similar to the standard log (x/xo) that you see frequently used, except that the formula we derived works for CO2 amounts starting with zero”
must come from somewhere. Where do the numbers come from? I cannot believe that they are based on observed data; I assume they have been estimated somehow. I also assume that this estimation uses the assumption I have referred to several times, and which you have not addressed, namely
“Fortunately, the global warming component, it being tied directly to the growing strength of the terrestrial greenhouse effect, is a uniquely radiative effect that can be addressed independently of the other climate complexities”
Is this assumption merely just an assumption, or is it based on sound physics, and in which case what is this physics?
I notice this formula was developed in 1988. Since then we have obtained a lot of observed data. As Girma, and others, keep pointing out, the observed data simply does not agree with your figures. Even making the most advantageous assumptions so far as CAGW is concerned, one cannot arrive at a total climate sensitivity that is anywhere near 1 C for a doubling of CO2; the number seems to be significantly less than even 0.8 C. What attempts have you made to reconcile the actual data from the last 23 years , with your estimated numbers?
My impression is that people like yourself believe that these numbers that claim a large amount of climate sensitivity, are written on tablets of stone; they are absolutely correct, and must not be challenged. If the observed data disagrees with the numbers, then the observed data must be wrong. viz Kevin Trenbeeth claiming that the missing heat (joules) is hiding in the deep oceans.
So what I would really like to know is about the assunption of only considering radiation in estimating cimate sensitivity, and I hope we can continue this discussion, so the other issues I have raised can also be discussed.
That is the logarithmic sensitivity of temperature due to atmospheric CO2 concentration. If this did not exist, then positive feedback effects would even be stronger. The logic is that this behavior has clamped the rise in temperatures during previous interglacial periods:
http://theoilconundrum.blogspot.com/2011/10/vostok-ice-cores.html
In the formula there are three numbers which modify x. These are
1.2 modifying x
0.005 modifying x squared
0.0000014 modifying x cubed
My question is, where do these numbers come from?
Andrew
Yes. But the magnitude of its CO2 sensitivity has not been corroborated by empirical data.
That is the key argument here.
A 2xCO2 “no-feedback” sensitivity of 1.0 or 1.2C is a nice hypothetical number.
Your formula for calculating this hypothetical number is nice. So is Myhre’s.
What is more important to a rational skeptic in the scientific sense is the actual climate response to increased CO2 concentrations in the real world.
This has not shown the sort of climate sensitivity (including feedbacks) as estimated by the models cited by IPCC.
In fact, the observed data would point to a climate sensitivity of around one-half to one-fourth of the mean value estimated by the IPCC models.
That is the dilemma, Andrew.
Max
The absorption spectrum of CO2 at ground level is subject to line broadening, a function of temperature and pressure.
The higher the altitude, the narrower the absorbance bands and bigger the extinction coefficient at the peak.
In the Earths atmosphere one has an onion, layers of less dense, colder, CO2 all the way up.
The peak extinction coefficient changes all the way up, but the spectrum narrows.
As you would expect, this makes a simplistic absorbance model impossible.
hunter: CO2 may or may not be the principle control knob, but it is certainly not the only control knob. For instance currently the sun is in a deep solar minimum.
Are you arguing that there is no greenhouse effect?
huxley,
Of course there is a greenhouse effect (or better named, Tyndall gas effect).
I complpetely agree that CO2 is not the only ‘control knob’ for climate.
That is one of the central failures of the climatocracy and their CO2 obsession.
Dr Lacis,
[“If you take away the non-condensing greenhouse gases, water vapor will condense and precipitate, and you will be left without a greenhouse effect.”]
Are you sure? All water vapour in the entire atmosphere will condense and precipitate? Do you have any evidence to support such a statement? No more water anywhere in the world will evaporate to become water vapour ever again? Fascinating.
.
Purely hypothetical, of course. Has there ever been a time when all the CO2 has been removed from the atmosphere?
.
I have asked you a few simple and polite questions on this thread (see link below) and I would really appreciate your answers to those questions.
http://judithcurry.com/2011/10/11/co2-control-knob-discussion-thread/#comment-121065
.
Kind regards,
Arfur, also Fred and David,
My statement that “If you take away the non-condensing greenhouse gases, water vapor will condense and precipitate, and you will be left without a greenhouse effect.” is clearly more rhetorical than literal.
As Fred is pointing out, atmospheric water vapor in Fig. 2 of our Science paper had dropped down to 10% of its normal value (before the model ran into a divide check when the sea ice hit ocean bottom) in response to zeroing out all of the non-condensing greenhouse gases. There is still the heating by solar radiation that is capable of maintaining atmospheric temperatures that are high enough to sustain atmospheric water vapor at the 10% level of current amount.
If the model had progressed further with total ocean freeze-over, and if the global surface albedo approached its Antarctica maximum value of 0.95, this would then greatly reduce the solar heating and drop the atmospheric water vapor to much less than the 10% value.
I don’t think that the atmospheric water would ever go to zero, since there is always some equilibrium vapor pressure, even for cold ice.
Also, I don’t think that atmospheric CO2 can ever be zero, even for snowball Earth conditions, given that there has been a biosphere of some sort for billions of years. On geological (million year) time scales, volcanoes are the principal source of atmospheric CO2, and the weathering of silicate rocks is the principal sink. The biosphere can act both to sequester CO2 and also to release it to the atmosphere. Since there is no direct interaction linking the CO2 sources and sinks, atmospheric CO2 can build up or diminish, as it seems to have done in the geological past. The ice core data show the level of atmospheric CO2 dropping to as low as 150 – 180 ppm during peak glacial periods. I imagine that it could go a lot lower than that, but I am not aware that the geological record would be able to show that.
Water vapor in the atmosphere seeks to be at its highest level possible. If the atmosphere were quiescent, the relative humidity would eventually reach 100%. But the atmosphere is anything but quiescent. Atmospheric motions move air parcels to significantly colder temperatures where the (excess) water vapor condenses and precipitates. Since the condensation and precipitation process are so much faster than evaporation, this has the effect of knocking the water vapor down from its maximum allowed 100% relative humidity value. The global average tropospheric relative humidity is thus only about 70%, instead of 100%.
That is the process that cycles water vapor though the atmosphere. To first order, the amount of water substance that the atmosphere can maintain in vapor form is going to depend on the atmospheric temperature structure (via the Clausius-Clapeyron relation). Just how the atmosphere sustains that temperature structure should not matter. Clearly, the non-condensing greenhouse gases provide that sustaining temperature structure through their greenhouse effect, which then enables more water vapor to be held in the atmosphere.
Solar radiation also provides atmospheric heating, but as we saw from Fig. 2 of the Science paper, this is only enough atmospheric heating to sustain water vapor at the 10% level of current climate.
We are in the process of running a climate model experiment where the radiative forcing due to the zeroed out non-condensing greenhouse gases is replaced by increasing the solar insolation by about 15%. This is of course not a perfect balance since the greenhouse forcing is latitudinally more or less uniform, while the solar radiative heating is concentrated in the tropics, being totally absent in the winter polar regions. But, this model run should demonstrate that, at least to zero order, sustained solar heating should work just like greenhouse heating to maintain the Clausius-Clapeyron allowable amount of water in the atmosphere.
Dr. Lacis,
Did you listen to Murry Salby’s podcast on Carbon cycle? What is your view on it?
http://judithcurry.com/2011/08/04/carbon-cycle-questions/
My take is that CO2 can be considered as quasi-condensing and therefore dependent mostly on temperature (or climatic factors in general).
No, but a little checking on Google tells me that poor Prof Salby is totally confused as to what is going on in the carbon cycle. There are large carbon fluxes cycling between the ocean, atmosphere, and biosphere. But what counts for the radiative forcing of global warming is the stuff that stays in the atmosphere, and atmospheric CO2 is being precisely monitored, having increased from pre-industrial levels of 280 ppm to near 390 ppm at present.
Coal, oil, and gas transaction records show that humans extract 9 gigatons of carbon each year. (Assuming similar density to water, 9 GT of carbon amounts 9 cubic kilometers of carbon that gets burned each year.) This produces 9 x 44 / 12 = 33 GT of CO2. The atmosphere is about 5 million GT of air. So this burned carbon adds about 6.6 ppm of CO2 to the atmosphere. Since only about 40% stays in the atmosphere, this will increase the atmospheric CO2 level by about 2.5 ppm. This is what keeps raising the atmospheric CO2 level, and this is all attributable to humans burning fossil fuel.
Prof Salby should check his facts more carefully before he speaks. The people who actually do the carbon cycle research understand what they are doing, and are not as easily confused as Prof Salby.
The people who actually do the carbon cycle research understand what they are doing, and are not as easily confused
Actually that is incorrect eg Marland 2008.
Ralph Rotty and I reported in 1984 that our estimate of global fossilfuel emissions had an uncertainty of ± 6% to 10% (90% confidence interval, which amounts to 0.6 to 1.0 Pg C uncertainty at the 95% confidence level), a range that seems appropriate still. The uncertainty in the emissions term is thus 1.5 to 3.3 times larger than the uncertainty in the atmospheric accumulation term.
The bottom line is that the details of the global carbon cycle and the details of compliance with emissions commitments are limited by the uncertainty of the emissions estimates. And the uncertainty
in the global total of emissions is increasing as the contribution increases of emissions from countries with higher uncertainty.
That these are fundemental problems in assumptions in carbon sinks is repeatedly emphasised in a number of papers eg Gloor 2009 Sarmiento 2010,2011.
On the other hand we could say that the carbon models capture the shape reasonably well ie an increase in efficiency by a factor of 4 say in NH land sinks Sarmiento 2010.
Maksimovich – As someone not engaged in this particular exchange of comments but familiar with your manner of commenting, I would like to ask you, as a courtesy, to do what most of the rest of us do when we wish to document our claims with references. Please link to the references! If that is impossible, please cite the complete reference (authors, journal, volume, pages, year). If there is some reason you can’t do that, I hope you’ll explain, but I don’t think it’s considerate of you simply to state a name and a year, requiring others to search around in hopes of finding what you’re referring to.
Regarding this particular subject, I think we have a reasonably accurate record of emissions, sufficient to draw the types of conclusions described above, but I would be glad to go to links you provide if they offer an additional perspective.
This is the reference he links to:
http://www.environmentportal.in/files/Uncertainties.pdf
I notice that the author is from Oak Ridge National Lab, which is the site that puts together some excellent CO2 statistics from fossil fuel usage.
http://cdiac.ornl.gov/trends/emis/meth_reg.html
This is the data that I have been using in my publicly available analysis.
So Marland is actually implicating himself and all his Oak Ridge colleagues?
Dr. Lacis,
Thanks. Regarding, the pre-industrial level of 280 ppm, I am not convinced. It was variable and temperature dependent in my opinion. Ice core records are highly questionable regarding gas concentrations.
http://robertkernodle.hubpages.com/hub/ICE-Core-CO2-Records-Ancient-Atmospheres-Or-Geophysical-Artifacts
The proportion of the human CO2 staying in the atmosphere is highly variable and depends on global temperature.
http://farm7.static.flickr.com/6088/6125488794_8ef0233067_b.jpg
http://farm7.static.flickr.com/6080/6125478512_1eb60e073e_b.jpg
This is also a good presententation and a different take on what causes atmospheric CO2:
http://www.kidswincom.net/climate.pdf
“No, but a little checking on Google tells me that poor Prof Salby is totally confused as to what is going on in the carbon cycle. There are large carbon fluxes cycling between the ocean, atmosphere, and biosphere. But what counts for the radiative forcing of global warming is the stuff that stays in the atmosphere, and atmospheric CO2 is being precisely monitored, having increased from pre-industrial levels of 280 ppm to near 390 ppm at present.”
It appear you didn’t understand what poor Prof Salby said.
Poor Salby is what some may consider a useful idiot. This is not meant to be disparaging because you need idiots (and skeptics) to make something idiot proof.
Salby is raising the point that the residence time of CO2 in the environment is not that long. This is true and his isotope analysis likely backs this up, but the adjustment time is the actual factor that needs consideration and he has nothing to say about that. It is therefore useful of him to bring up the need for a good definition of adjustment time, which will serve to make the carbon cycle arguments stronger and idiot proof.
Dr. Lacis,
First, thank you for returning and engaging with posters here.
Recent studies in limnology show that freshwater systems are responsible for as much carbon sequestration as the earth’s oceans.
I do not beleive that carbon cycle estimates have taken that into account.
Your case for CO2 playing a major role is very strong. Yet consistently predictions made about the impact of this role seem to be wrong.
The missing ocean heat content, the missing troposphere hot spot, the lack of excursionss from the historical record of weather events all comes to mind.
Do you see the possiblity that skeptics of the idea that Earth is facing a “major climate crisis”, to parpaphrase many of your colleagues are coming to that conclusion based on a reasonable look at the situation?
I agree very much hunter! I disagree with Dr. Lacis completely, but I respect his engagement.
I am not discounting the human contribution to atmospheric CO2, but for you to write criticism of others knowledge of the carbon cycle, and then see you write about the increase in atmospheric CO2-
“this is ALL attributable to humans burning fossil fuel.”
This demonstrates you have eliminated any natural variability in the emission or absorption rates of non human emitted CO2. Perhaps you need to look in the mirror regarding the lack of carbon cycle knowledge.
That is actually one of the strongest and most robust assertions in climate science. It is actually removed from climate science and is more a result of earth science (ocean, land, and atmosphere) chemistry and physics. If global warming never occurred, this rate of increase would remain, and the human origin would stand firm.
You can’t provide one shred of evidence of a natural origin for this abnormal monotonic increase in CO2, and AFAICT no one ever has.
Web
If you are writing that there is no evidence that natural emissions rates change due to changes in environmental conditions you are wrong. There is quite a bit out there on the topic. Here is one I had handy, but I have read many others.
http://www.scientificamerican.com/article.cfm?id=soils-emit-carbon-dioxide
In regards to changes in absorbtion rates there is also evidence that plants absorb different amounts of CO2 over time as conditions vary-such as more CO2 is in the atmosphere. If I am understanding your position, you are writing that YOU KNOW that the 95% of total emissions and 100% of absorbtion remains completely stable, and only the human factor changes. That is incorrect
That’s why it is called a cycle. There is no net flow either in or out because land and sea area for biota is conserved. Burn down a forest and it will grow back, and the net impact is zero.
However, when we peel the layer of the earth open and expose all that organic matter from millions of years ago, that becomes excess that won’t fit into the natural carbon cycle. In other words, that excess won’t find its way back thousands of feet into the ground, and it has to compete with the rest of the CO2 for temporary residence..
It is a very simple concept that has many analogies in science and technology, but people for some reason can’t intuit how we have perturbed the closed loop.
Dr Lacis,
I thank you for engaging on this thread.
You say:[“Clearly, the non-condensing greenhouse gases provide that sustaining temperature structure through their greenhouse effect, which then enables more water vapor to be held in the atmosphere.”]
.
I’m not sure you can say ‘clearly’ on any specifics in the climate debate, especially on the subject of attempting to quantify the effect the radiative processes have in the atmosphere. In particular, the problem with your statements on this thread is that your assertions lack any serious corroboration with real-world, observed data. If you think CO2 contributes 25% of the GE, that equals 8.25 deg C of the 33 C GE. In 1850, that would have equated to appx 8.02 C. Unless you then assert that the CO2 contribution was less in 1850 (do you?), the minor (negligible?) increase in the contribution of CO2 to warming is an anomaly far removed from the increase in CO2 itself.
.
To me, it is equally ‘clear’ that the contribution of CO2 to the GE is more likely to be in the region of 5%, not 25%. The problem is that observed data simply does not support the theory that CO2 can have a significant effect. Water vapour will absorb LW radiation from the Earth without the benefit of CO2 but I would never try to argue that the removal of CO2 is even likely, let alone use that as a supporting argument to make my case. There comes a time when hypothetical arguments run their course and flounder on the rocks of evidential fact (or as near to fact as anything is in the climate debate). The problem with referencing your Fig 2 is that it is based on a model, the input of which is based on the assumptions made by the modeller and his ability to formulate an algorithm which accurately depicts the Earth’s atmosphere. If the observed data does not support the model, then the model needs to be reviewed. It is more likely, in my opinion, that the basic radiative theory will need reviewing, particularly in any quantitative sense.
.
Thanks again for your engagement here.
Apologies for the permanent use of italics…
Arfur, you have to ask yourself these questions. If you take all the CO2 out of the atmosphere, you agree the temperature will drop about 8 degrees C, so
1. What happens to the water vapor when the temperature drops by that amount?
2. Could it not reduce leading to an even lower GHE and a further temperature drop?
3. Would the colder temperatures lead to more snow and ice albedo leading to an even further temperature drop?
This is the basis of the paper. It quantifies these feedbacks that end up with a very cold temperature.
Jim D,
What questions are you talking about? Of course I don’t have to the questions you pose. Not only are they purely hypothetical, they don’t make any sense. You say that I agree the temperature will drop by about 8 deg C or so. I most certainly do NOT agree with that!
The point is that CO2 cannot be responsible for that contribution (25%) of the GE, according to observed data and logic. The GE of around 33 C has existed for some time – a lot longer than the IPCC’s quoted start of AGW. The relatively huge increase in CO2 has not brought about any significant warming, even if you could state with any certainty how much has been due to CO2, so the ‘8 deg C or so…’ is quite simply and quite observably incorrect.
Your questions are therefore irrelevant and I don’t have to ask them.
Arfur, even a one-dimensional radiative transfer model can show that 10-25% is about the extent of the CO2 contribution to the downward clear-sky longwave flux in different areas of the world. What happens if you permanently remove that part of the flux? Maybe you just disagree with the science of radiative transfer or physics in general?
Jim D,
You kindly prove my point, you argue from a model, whereas I am arguing from observed fact (or as close at it gets to ‘fact’ in this debate). I don’t accept the model veracity. Dr Lacis issued his “CO2 accounts for 25% of the GE…” based on a model. I have pointed out that observed data does NOT support this statement – by a large margin! Now you are trying to argue in support of his point – using models! I can’t emphasise enough that there is a logical and evidential anomaly in the observed data and Dr Lacis’ assertion. If you look back through this thread, I have asked him this question on numerous occasions and he has refused to answer. If he was confident in his paper, he would answer and prove me wrong. He doesn’t. Your use of model reasoning does not answer the question. Purely hypothetical arguments are unnecessary when there is sufficient data to provide real-world answers. It is really simple… If nGHGs contribute 25% to the terrestrial Greenhouse Effect, why has a 40% increase in the main nGHG (and similar increase in the others) not led to a significantly greater warming than has been observed, when we can’t even say with confidence exactly how much of the 0.85 C warming is actually caused by these nGHGs?
.
I answer to your final question, I do not disagree with the theory of radiative transfer, but I do agree with the assumed quantification of that theory based on modelling. Once again, the data does not support the theory. If ‘physics in general’ wants to be treated with respect, it should start looking at changing the theory not finding excuses why the data does not support that theory.
Sorry JimD,
my last paragraph should read so:
In answer to your final question, I do not disagree with the theory of radiative transfer, but I do disagree with the assumed quantification of that theory based on modelling. Once again, the data does not support the theory. If ‘physics in general’ wants to be treated with respect, it should start looking at changing the theory not finding excuses why the data does not support that theory.
Sorry for the typo!
Arfur, I agree regarding your point of arguing from a model. The consensus’ motto is “claims against models require extraordinary evidence”. Observed facts are not enough!
Edim,
Thanks for that. It is disappointing to see Dr Lacis once again avoid the question regarding his claim of 25%. The trouble with ‘blog debates’ is that they are such a transient activity. One can ignore or disengage from a blog debate and it will soon be history and hence forgotten in a short time. His paper will last far longer and maintain the appearance of veracity in the eyes of many who refuse to question ‘model’ science.
You are right – observed data does not seem to be enough…
Arfur, I specifically mentioned radiative transfer models (MODTRAN is an example). If you give a radiative transfer model the properties of an atmospheric profile (gases, water vapor, temperature, as a function of height), it can give you the downward radiative flux at the surface. Yes, the state of physics is such that this is highly predictable and there is no mystery here.
We are in the process of running a climate model experiment where the radiative forcing due to the zeroed out non-condensing greenhouse gases is replaced by increasing the solar insolation by about 15%
Very neat. What’s the trick? Obviously not moving Earth 7% closer to the Sun.
the greenhouse forcing is latitudinally more or less uniform
The CO2 level is latitudinally more or less uniform. By what reasoning does this make the greenhouse forcing so?
Vaughan,
Actually, the Sun-Earth distance changes with season within the GISS ModelE GCM according to fairly precise Sun-Earth ephemeris that is being used to calculate the incident solar radiation at each model gridbox as the Earth rotates through each 30-minute time step. The model’s solar energy specification also includes the small 11-year solar sunspot cycle variability. The 15% increase in solar radiation is a very large solar radiative forcing, but quite easy to implement since the solar constant is one of the input variables of the soalr radiation model.
The CO2 forcing is latitudinally uniform because CO2 is fairly uniformly mixed in the atmosphere because of its long residence time. If expressed as a radiative flux change, there is a significant latitudinal dependence as a result of the latitudinal temperature dependence of the Planck function. But when expressed as the equivalent no-feedback ΔTo temperature change (about 1.2 for doubled CO2), this temperature change is latitudinally fairly uniform. See Figure 2.8 of Lacis and Mishchenko (1995), which is actually available on my Roger Pielke Sr. blog posting – the commentary on the Atmospheric CO2 Thermostat
Dr Lacis,
Would providing the Moon with an atmosphere of CO2 raise the maximum surface temperature above present levels when the surface is facing the Sun?
What depth of 100% CO2 would be required to double existing maximum temperatures on the Moon?
The calculation would obviously be trivial for you, which is why I ask.
Thanks.
Well, there is a clear precedent. The temperatures on Venus are about double the Moon’s max. And the Moon actually absorbs quite a lot more solar energy than Venus, because of its much lower albedo. So 90 MPa should do it easily.
the Moon actually absorbs quite a lot more solar energy than Venus, because of its much lower albedo.
Picky point: Venus absorbs
(149.6/108.21)^2*(6051.8/1737.1)^2*(.1/.88) = 2.64
times the solar energy absorbed by the Moon. But you obviously had in mind solar irradiance, i.e. radiant flux density per sq. m, for which the arithmetic bears you out:
(149.6/108.21)^2*(.1/.88) = 0.22.
Dr. Lacis,
” (about 1.2 for doubled CO2), this temperature change is latitudinally fairly uniform. ”
I agree, but I get 1.2 at the tropopause, approximate 0.85 at the surface. What is the frame of reference of the models relative to CO2 impact?
Actually, the Sun-Earth distance changes with season within the GISS ModelE GCM according to fairly precise Sun-Earth ephemeris that is being used to calculate the incident solar radiation at each model gridbox as the Earth rotates through each 30-minute time step.
Sorry, I’m not following. Are you saying that over the period covered by your ephemeris the solar insolation actually does increase by 15%, or are you merely asking your model what would happen were the insolation ever to increase by that much?
If the former, when did or will this 15% increase happen?
I was under the impression that insolation varied by at most 7% over a period of millions of years. I’d be more than happy to be set straight about that.
But when expressed as the equivalent no-feedback ΔTo temperature change (about 1.2 for doubled CO2), this temperature change is latitudinally fairly uniform. See Figure 2.8 of Lacis and Mishchenko (1995), which is actually available on my Roger Pielke Sr. blog posting
Presumably this is the second figure in the blog posting. (I couldn’t locate a copy of the 1995 paper online.) I have no intuition at all for why the dotted curve should be so flat, so I’m going to have to think about it for a while. It’s very interesting.
Vaughn,
The solar “constant” varies annually from ~1320 to 1415 W/m2 or so (just back of envelope, there might be more precise literature) because of Earth’s eccentricity ( the difference between aphelion and perihelion). Keep in mind though that for planets whose thermal response time is long, the temperature manifestation will be smoothed out, although it is quite possible to have planets with very large “distance seasons.” Also, the temperature only varies as the square root of the distance from the sun (since radiation drops off as an inverse square, but temperature is related to the 1/4th power of the flux). For Earth, this is all of decidedly secondary importance when compared to its tilt in creating a seasonal signal.
You are right though that the sun’s direct output does vary (by ~7% per billion years) as a result of nuclear fusion changing the Helium to Hydrogen ratio in the core. This changes the central pressure, and a temperature increase/increased luminosity is a consequence of the need to maintain hydrostatic equilibrium.
Even though CO2 is well-mixed, there are latitudinal variations in radiative forcing that arise from changes in the vertical temperature structure and tropopause height, and also differential overlap with water vapor bands. It’s not obvious to me that the no-feedback dT should be horizontally uniform but I suspect it would be to zeroeth order at least. I’m also not convinced the reason for polar amplification signals are well understood even in a feedback world (certainly ice-albedo changes are a small part of the answer, but the phenomenon is much more robust in models to different climate states or theoretical planet configurations, so I am not convinced that is of first order importance)
Oh duh, I am so stupid sometimes. I was thinking globally but Andy is talking latitudinally about a 15% seasonal variation. He was presumably thinking I had some other more subtle problem in mind since how could I possibly not understand the latitudinal dependence on season. Otherwise he’d have said something like “you do realize we’re talking about seasonal/latitudinal variation and not decadal/global variation, don’t you?”
It’s not obvious to me that the no-feedback dT should be horizontally uniform but I suspect it would be to zeroeth order at least.
For your zeroth order approximation, one natural way flatness could result would be if two terms cancelled. Is that the case in your approximation, and if so what are they?
“Would providing the Moon with an atmosphere of CO2 raise the maximum surface temperature above present levels when the surface is facing the Sun?”
Co2 would freeze on the unlit side- and stack up in lunar polar region.
How about a large greenhouse on the Moon- say 10 km in diameter and 5 km high. Put 1 psi of CO2 in dome [a around 1000 times more CO2 on Earth and about 20 times more than on Mars].
Would the lunar surface inside the dome increase in temperature.
Assume dome is made of only very transparent glass and say 4″ thick
[Which might actually be possible to do, btw].
Thank you. Why doesn’t the atmosphere freeze on Mars? Why not on Earth (same distance from the Sun)?
What physical principle would cause frozen CO2 to stack up in the polar regions? Why wouldn’t it stay where it froze, or move to the equator due to centrifugal force?
Wouldn’t the frozen CO2 become gaseous when the Sun hit it?
I assume you cannot provide the answer to my questions, but thank you for your interest.
Maybe Dr Lacis can assist me.
first thing to you might want to ask Dr Lacis would be how much sunlight the dark side of the moon gets
Unlike many climate science deniers the Moon, like the Earth, doesn’t actually have a “dark side”. Do you mean far side? The Moon always faces the Earth with the same face so the far side is hidden from Earth view.
It still gets just as much sun. There is a lunar day which is about 28 days long , depending on precise definition.
ignorance – which is probably the same reason the alarmists here seem to deny the Earths history is less than 10,000 years long and think that Co2 regulates the Earths temperature when historically it has always been the otehr way around.
edit – “more than 10,000” instead of “less than”
“Why doesn’t the atmosphere freeze on Mars? Why not on Earth (same distance from the Sun)?”
The atmosphere on Mars does freeze:
“The planet Mars also has polar ice caps, but they consist of frozen carbon dioxide as well as water. The ice caps change with the Martian seasons-the carbon dioxide ice sublimes in summer, uncovering a surface of layered rocks, and then reforms in winter.”
http://en.wikipedia.org/wiki/Polar_ice_cap#Mars
“What physical principle would cause frozen CO2 to stack up in the polar regions?”
Dark craters on the Moon are cold, as cold 30 K- far colder than anywhere on Mars. In cold area the CO2 or almost any gas freezes- so it would create a vacuum and draw any atmosphere gas to these dark craters. Though it would built up after some point and no longer be a “dark crater”.
In addition if one wanted more atmospheric pressure than on Mars, which around 1/100th of earth pressure, if it has higher pressure it lowers the freezing point of C02. Coldest on Mars is -140 C [110 K]. Coldest nite side on Moon is -153°C.
So put CO2 on the Moon the gas will race to polar regions and nite side and freeze, but every lunar day [28 days] the CO2 will melt, and race to the now nite side and polar regions. Evenually it will end up stacked up on poles so high the sunlight will warm it- and rest of it will “daily” race across the moon and re-freezing as the Moon slowly rotates.
So unless the CO2 results in warmer nite side- it doesn’t matter how CO2 you put on the Moon- it will freeze out on the nite side.
I would guess it would cool the Moon.
And make it pretty windy:)
But anyhow it makes it complicated- and a dome wouldn’t have these kind of complications.
“lowers the freezing point of C02”
I mean raises.
With earth pressure [1 atm] CO2 freezes at -78.5°C
and with Mars pressure it’s -140 C
In addition the triple point of CO2 is at -57 °C and 517 kPa (about 5 atm). Liquid CO2 occurs only, when both the temperature and the pressure are above the triple point values. At lower pressure only solid and gas phases are possible.
These values and the freezing point values given by gbaikie explain well, why CO2 doesn’t freeze or condense on Mars.
In addition the triple point of CO2 is at -57 °C and 517 kPa (about 5 atm).
And of course the mean surface pressure on Mars is nowhere near 5 atm, being more like .006 atm.
On Venus however it is 92 atm, and the temperature is around 740 K. The critical point of CO2 is at 304.19 K and 72.8 atm, making Venus’s atmosphere a supercritical fluid, a substance having characteristics of both a gas and a liquid, an interesting difference from both Earth and Mars.
This thread, and the previous one on the topic, have become much more interesting now that Andy Lacis has returned to respond to comments and answer questions – not only about the Lacis et al paper but also in regard to other matters including GCM construction. This has led not only to informative answers by Andy but also to more penetrating questions than often characterize these threads. I hope it might serve as a model for future guest posts by expert contributors who are not denizens of this blog but come by to offer their perspectives. I’m not sure how Judith Curry came to arrange Andy’s participation, but it seems to have worked well, and the conversations may not even be finished yet. Also, once the dialog has been engaged at a high level of scientific sophistication, it’s gratifying that the focus has been on the science itself. That may serve as a model encouraging other climate experts to participate as guests in the future.
Agree 100% Fred.
I thoroughly agree, Fred, just as long as Andy stays around and discusses issues until we arrive at some form of resolution. This remains to be seen..
just as long as Andy stays around and discusses issues until we arrive at some form of resolution.
Wish the 112th Congress would do that.
Fred,
Mark the calendar, but I do agree with you completely on this as well.
I will even commit to not permit myself a heated response to a guest post again.
Dr. Curry has indeed built something very close to a virtual salon, and that implies a need for better manners on the part of at least myself.
Dr. Lacis’ decision to return here and engage with those who disagree with him as well as those who agree has been a very positive development. I find myself re-reading his posts to deepen my understanding of his position.
I would be quite interested to see any opinions regarding this.
http://www.pnas.org/content/99/19/12011.full.pdf
and any comments on historical atmospheric CO2 data that is derived from methods other than ice core analysis
I think leaf stomata reconsctuction is closer to reality than ice records.
Jim in SC
There is the stuff gathered by Ernst Beck.
http://www.biomind.de/nogreenhouse/daten/EE%2018-2_Beck.pdf
It has been discarded as irrelevant (first by Keeling, then by IPCC).
Max
manacker
thanks for the link. It’s pretty obvious why the IPCC dislikes any Co2 data other than Antarctic Ice core stuff
I’m glad to see a solid technical discussion here too. This seems an appropriate time and place to ask a question I’ve wondered about.
Last June on Chris Mooney’s Discovery blog he had a self-congratulatory topic on how Democrats are more scientific than Republicans … yada yada … then quoted Prof. Kerry Emanuel:
A regular commenter who goes under the nom de web, Nullius in Verba, asked Mooney politely, “Can you show us this “back of an envelope” calculation, please?” Whereupon Mooney scolded back, “Nullius, this is a warning. Your comments are verging on hectoring at this point,” then closed comments a few hours later.
I really don’t understand why — especially in a post celebrating the glories of the “Enlightenment Ethic” which, Mooney tells us, Republicans sadly do not share — a straightforward request to support a scientific claim should not only go unanswered, but be met with a complaint and shutdown of the discussion.
Mooney and Emanuel say that this back-of-the-envelope calculation is well-known even to college students of atmospheric science. What might it have been? Why couldn’t Mooney, a science writer of some repute, locate it and present it?
@- huxley | October 14, 2011 at 3:17 pm
“As Emanuel explained in his written testimony, today’s MIT atmospheric-sciences students can do “hand calculations or use simple models” to show why global warming is a serious concern. Such calculations show that the planet will warm somewhere between 2.7 and 8.1 degrees Fahrenheit if we allow carbon-dioxide concentrations in the atmosphere to double.
….Mooney and Emanuel say that this back-of-the-envelope calculation is well-known even to college students of atmospheric science. What might it have been? Why couldn’t Mooney, a science writer of some repute, locate it and present it?”
No idea why Mooney did not reply, but the ‘back of an envelope’ description of such an equation is a little disingenuous. Any such claimant to such an equation requires rather more knowledge and data than can be fitted onto the back of an envelope…
But the most likely candidate for the key equation in question would be the one for energy flux –
Iλ(0) = Iλ(τm)e-τm + ∫ Bλ(T)e-τ dτ
which states –
“The intensity at the top of atmosphere equals..
The surface radiation attenuated by the transmittance of the atmosphere, plus..
The sum of all the contributions of atmospheric radiation – each contribution attenuated by the transmittance from that location to the top of atmosphere.”
I am unsure if this post will duplicate the correct super/subscripts and calculus signs of the original which can be found here –
http://scienceofdoom.com/2011/02/07/understanding-atmospheric-radiation-and-the-%E2%80%9Cgreenhouse%E2%80%9D-effect-%E2%80%93-part-six-the-equations/
and explained in detail including its derivation and the succeeding steps to relate energy flux to surface temperature.
izen, if we could only harness that energy.
izen: Looks pretty good to me notation-wise, but you’re right that it would take some explaining. Thanks!
My fears seem to have come to pass. Andy Lacis seems to have disappeared, and I have not has an answer to my question as to where one of his claims comes from, namely
“Fortunately, the global warming component, it being tied directly to the growing strength of the terrestrial greenhouse effect, is a uniquely radiative effect that can be addressed independently of the other climate complexities.”
Anyone able to help?
That may be why he is missing. Finding the right answer.
Hypotheses abound.
CO2 “control knob” postulations such as that proposed by Andrew Lacis seem to be based largely on model simulations based on these hypothetical deliberations.
The greenhouse theory itself seems to be solid.
Based on this theory, the impact of all natural GHGs on our climate appears to have been reliably estimated at around 33C.
H2O is the principal GHG in our atmosphere and CO2 is second.
Just how much of the estimated natural GHE is caused by water (vapor, liquid droplets and ice crystals) and how much by CO2 is unknown.
Based on hypothetical considerations, various estimates of the CO2 impact have been made. These range from 9% to 26% of the total (Gavin Schmidt), but it is generally considered that the range is between 5.2°C = 16% (Lindzen) and 7.1°C = 21% (Kondratjew).
Various theoretical formulas have been suggested for the CO2/temperature correlation. Most are based on a logarithmic relation at the sort of levels that have been or will be experienced, with some formulas (Lacis) using a modified logarithmic version, which would theoretically apply at 0 ppmv CO2 as well. This equation would show a clear sky 2xCO2 temperature impact of 1.2°C
IPCC uses the relation of Myhre et al. This shows a 2xCO2 impact of around 1.0°C.
These are both hypothetical values, of course, but they have been used in climate models.
If this is the impact of CO2 on our climate, then we have nothing to fear from human CO2 emissions.
We know from WEC estimates that there are only enough “inferred possible total fossil fuel resources in place” on our planet to reach around 1065 ppmv atmospheric CO2 concentration when they have all been used up, and at 1°C warming for each doubling the absolute maximum ever GH warming from CO2 can be calculated:
dT (390-1065 ppmv) = 1°C * ln (1065 / 390) / ln2 = 1.4°C
This is not alarming, as it is only around twice the slight warming we have already seen since 1850.
But now come the “feedbacks”.
There is no agreement on the net overall magnitude or even the sign of all feedbacks.
Water vapor is expected to increase causing a positive feedback: IPCC assumes essentially constant RH with warming, citing the Clausius-Clapeyron equation, Minschwaner + Dessler show increased water vapor content with warming but significantly less than would be required to maintain constant RH, long-term radiosonde and satellite data even show a net reduction of water vapor content with warming.
Clouds are the biggest unknown. IPCC models all estimate a strongly positive net cloud feedback, conceding, however, that “cloud feedbacks remain the largest source of uncertainty”, but these estimates are coming under attack based on more recent physical observations (Spencer, Lindzen), which show a net overall negative cloud feedback.
So why not simply look at empirical data, rather than relying on complicated model simulations based largely on hypothetical deliberations on feedbacks?
We have the observed temperature trend from 1850 to 2011, based on the HadCRUT3 global surface temperature record.
This indicates a warming of 0.7°C over the entire time period.
We have a measured atmospheric CO2 concentration today (Mauna Loa) of 390 ppmv.
There is no direct measure for 1850, but IPCC cites Vostok ice core data that would suggest a concentration in 1850 of around 290 ppmv.
But now we come to a dilemma. How much of the past warming was caused by natural factors and how much by anthropogenic forcing from CO2?
IPCC AR4 WG1 has made some estimates:
– 93% of the total forcing over the period 1750-2005 was due to anthropogenic forcing (only 7% due to natural = solar). (Here we must add that IPCC concedes that its “level of scientific understanding of solar forcing is low”)
– all other anthropogenic forcing factors beside CO2 cancelled one another out, so CO2 forcing = total anthropogenic forcing
If we accept these IPCC estimates, we can now make an estimate of the future temperature response to increased CO2, based on actual past observations:
dT (390-1065 ppmv) = 0.93 * 0.7C * ln (1065 / 390) / ln (390 / 290) = 2.2°C
Again, this is not very alarming. The “maximum ever possible” GH warming from human CO2 based on actual physical observations to date is just around three times the amount we have seen since 1850.
And if we question the IPCC estimate of “93% anthropogenic forcing” (several solar studies suggest it was only ~50%), the estimate becomes even lower.
IOW, the physically observed data do not support alarming predictions of future human-induced GH warming.
The only way to get there is either to “cherry-pick” shorter warming cycles in the past record or to program hypothetical positive feedbacks into the models, which double or triple the physically observed temperature /CO2 correlation.
It is pretty hard to refute the observed facts, but let’s see if anyone bites.
Max
Max. I agree with you completely. One thing I have noticed after reading this particular thread, is that the proponents of CAGW are very good at arriving at figures with respect to what happens after adding CO2 to the atmosphere; e.g estimates of climate sensitivity. However, so far as I am aware, none of these warmists has ever bothered to check any of these numbers against the observed data the way you have Max. Surely, if the warmists were proper scientists, they would go out of their way to check their estimates against observed data; the way Roy Spencer is trying to do.
This, to me, is just another example of why the proponents of CAGW are not doing physics the way I was taught in Physics 101 at Cavendish Labs. Cambridge..
Max – There are quite a few serious errors in your comment – either false statements or statements that give a false impression. Since most of these points have been well discussed previously, I expect you know what I’m referring to, but I’ll only mention one for illustration. You cite the Minschwaner and Dessler paper on relative humidity while knowing that there is other evidence for a different conclusion, with neither paper being decisive. The proper thing would have been to mention both, and failure to do that is the mark of someone with an agenda other than to promote accurate understanding. If I thought that your errors were all inadvertent, I would try to address each of them, but my sense is that you don’t wish to correct them but rather to use them as ammunition in a political conflict. For that reason, I’ll simply mention that this is my perception, and that other readers can judge what you claim as they see fit.
OK, I would like to see your explanation of the Vostok Ice Core data which shows a 12K temperature swing with less than a doubling of CO2. I suppose you have a theory for this? Either CO2 is acting like mercury in a thermometer as a passive observer, or it is actually influencing the result.
The point is that, regardless of any issues of AGW, earth scientists will still have an innate curiosity to figure out why that is so. You can’t wish that away, you can’t use heuristics to explain it, and your presentation of “facts” will have zero impact on scientific progress. The way I think about this is pretty simple, in that we need a reasonable model to either (1) understand what is going or (2) be able to do anything about it. Let me retrieve a quote from my book that sums it up:
I was reminded by this yesterday when I spotted the reference to Ashby on the MetaSD blog titled “Modeling is not optional”. BTW, watch this MetaSD video takedown of Salby if you want to see how a real systems guy tackles the problem
WHT
You refer to the Vostok record.
I have only taken the IPCC AR4 historic CO2 curve (insert in the CO2 chart in Figure SPM.1.), which is based on Vostok.
This shows that the CO2 level was around 290 ppmv in 1850.
I have no explanation for the older Vostok data of several hundred thousand years ago, which (as I recall) showed CO2 lagging temperature by several hundred years, and is not pertinent to the 1850-2011 calculation in any case.
I would suggest to you that “earth scientists” should “have an innate curiosity to figure out” why temperature only increased by 0.7°C while CO2 rose from around 290 to 390 ppmv, and what this tells us about CO2/temperature response.
The rest of your post is interesting, but also not directly pertinent to the observed CO2/temperature response since 1850, and what it tells us about future GH warming from CO2.
But if you have any specific comments relating to that, I would be interested in seeing them.
Max
From the older Vostok data, a 10 PPM trend change of CO2 corresponded to almost a 1K change in temperature. So today, either some latent behavior is building up, or CO2 was only acting like a thermometer and now we have decalibrated the thermometer with excess CO2..
Max, you have ignored the offsetting effect of aerosols by assuming 0.7 degrees is the full effect of CO2. It is easy to argue that aerosols and global dimming have reduced the effect by 0.4 degrees which doesn’t sound much, but affects your figures a lot. If the CO2 effect is then 1.1 degrees (0.7=1.1-0.4), and the aerosol effect has stopped growing since the 70’s as it appears to have, the remaining effect is your 2.2 degrees multiplied by 1.1/0.7 which is over 3 degrees. So you rely on aerosol effects growing at a rate that offsets much of the warming when the evidence of recent decades shows that growth is not happening. Do you really expect aerosol effects to grow in proportion to CO2 or did you forget to account for them?
Jim D
You write:
I suggest you check out IPCC AR4 WG1 Figure SPM.2.
You will see that from1750 to 2005 all anthropogenic forcing factors contributed 1.6 W/m^2, while CO2 alone contributed 1.66 W/m^2. This is because all other anthropognic forcing components (aerosols, other GHGs, etc.) essentially cancelled one another out.
The “full effect of CO2” is 93% of 0.7C (the other 7% is from natural forcing, according to IPCC).
To answer your question: No,. I “did not forget to account for” aerosol effects; II have simply used the IPCC estimate of past impact of aerosols, etc (namely, that this effect was cancelled out by other GHGs, etc.).
Check it out.
Max
You still assume that the aerosol effect will grow in proportion. The CO2 forcing difference between 1065 ppm and 390 ppm is 5.3 W/m2, which is easily capable of producing eventual warming of more than 3 degrees, especially when you consider that we had a 0.5 C warming from a forcing increase of 0.7 W/m2 over the last 30 years.
JimD
I do not “assume” anything.
I simply used the IPCC assumption on aerosols for the past to determine the observed CO2/temperature response of the past, using the physically observed temperature and CO2 data of the past..
As to CO2 forcing from 390 ppmv to 1065 ppmv, I have just shown you that the empirical data would support a temperature response of 2.2 degrees (not “more than 3 degrees”).
Forget “the last 30 years”, Jim D. Look at the entire 150 years. You know that over “the last 30 years” there was a warming cycle that is statistically indistinguishable from another 30-year warming cycle from 1910 to 1940 (when there was very little added CO2), and that between the two there was a 30-year cycle of slight cooling, despite accelerated CO2 emissions in the post-war boom years.
You should not “cherry-pick” out one of these repetitive 30-year upward/downward “blips” but concentrate on the big picture instead, i.e.the entire observed record since 1850.
That is what I have done.
Max
manacker, the reason to take the last 30 years is that in that period the aerosol effect did not grow much (unlike prior to 1980), and the sun stayed fairly constant (unlike prior to 1950), so this leaves us with a clean CO2 signal to compare with global warming.
Jim D
You have given me a rationale for “cherry-picking” the past 30 years out of the observed 160+ year temperature/CO2 record.
I have given you another rationale for NOT doing so.
Max
There is no direct measure for 1850, but IPCC cites Vostok ice core data that would suggest a concentration in 1850 of around 290 ppmv
I’ll take a small nibble on this one, I spent most of last evening looking at the ice core Co2 data and doing a casual comparison of the data to GEOCARB and stomata based records that I could find on the net. It is obvious even with a casual observation that the Ice core data does not match either the CO2 thermostat theory nor does it fit the temperature controls the CO2 theory.
No big original discovery there but It may be something some of the professionals here might want to examine in detail.
Jim in SC
I would agree with you that the jury may still be out on the validity of the Vostok record regarding 19th century atmospheric CO2 levels, especially in light of some of the later papers you cite, but I used this data (as accepted by IPCC) to show that , even using these figures, the empirical data do not support an alarming greenhouse warming resulting from human CO2 emissions.
None of the posters here has been able to refute this so far, and I am still waiting.
Max
Fred Moolten – Thanks for your response.
I am a bit confused as to why you would take the time to compose a response to a post that was not even directed specifically at you and then not come with any specific rebuttals in your response.
You state, “there are quite a few serious errors in your comment – either false statements or statements that give a false impression”, but you fail to specifically list or rebut such “serious errors, false statements or statements that give a false impression”, so I can only assume that your statement was simply bluster with no substance.
“Have been discussed previously” is a simple cop-out, Fred. (It appears to be one of your standard waffles, when you run out of sound arguments.)
You remark that I only mentioned M+D as far as water vapor feedback is concerned. This is incorrect. I also mentioned the IPCC estimates as well as the NOAA radiosonde/satellite record. I did not mention all the many model studies backing up the IPCC estimates. I simply mentioned enough specific examples to show that the magnitude of the water vapor feedback is still very much unknown (which you have not been able to refute and have even conceded in an earlier post).
You speculate about my “agenda”.
This appears to me to be a side-track to avoid the main topic.
I think we should leave “agenda” speculations out of the equation here, Fred, and stick to the science. This is a “technical discussion” thread.
I have shown that empirical data (observed historical CO2 and temperature records) plus IPCC assumptions on past natural versus anthropogenic forcing suggest that an increase of atmospheric CO2 from today’s 390 to a possible future upper limit of 1,065 ppmv would result in greenhouse warming of 2.2°C.
If the IPCC estimates on past natural forcing are substantially understated, then the impact will be even less.
Come with some specific arguments against this conclusion, which are based on empirical data (rather than simply model simulations), if you can.
Otherwise I will have to conclude (as may many others here) that you have no specific arguments and it’s all just bluster.
Max
I
If you think you’re fooling anyone, Max, it’s probably yourself. The Minschwaner/Dessler relative humidity case is only one example of misrepresentation of evidence, it being the only citation you provided for evidence, while referring to IPCC “assumptions”, and then pretending in your subsequent comment that you had offered an objective overview. I don’t think knowledgeable readers will be deceived. Your other mistakes will also be apparent to knowledgeable readers. Having discussed them previously, as have others, I won’t waste time with repetition. If you want to consider my unwillingness to waste time as “bluster”, be my guest, but again, don’t think you’re fooling anyone.
In any case, Max, I believe the regular participants here already have perceptions about each other, and this little exchange of ours isn’t going to influence that. My comment was designed for any casual reader who happened to stop by and might consider taking you seriously. Some still might, but I would advise them to be careful. That’s all I need to say, because readers will make up their own minds.
I did neglect to mention re water vapor that you also cherry-picked radiosonde data as additional evidence, failing to mention that is single example is contradicted by multiple others and is explainable by technological errors. However, I don’t want to fall into the trap of arguing about all of your errors, because that leads to interminable exchanges if past experience is a guide.
Fred,
Come with specifics, Fred, not silly accusations.
If you cannot refute what I have written, why did you even bother to respond to it?
Instead you come with the cop-out phrase:
“All of my errors?”
Sorry, Fred – let’s get specific.
Is the HadCRUT3 temperature record, which shows a 0.7°C warming from 1850 to today in “error”? If so, what should this warming be in your opinion?
Is the Mauna Loa CO2 measurement showing 390 ppmv today in “error”? If so, what should it be in your opinion?
Is the IPCC estimate (based on Vostok) of ~280 ppm in 1750 and ~290 ppmv in 1850 in “error”? If so, what should the correct value be in your opinion?
Is the IPCC estimate that 93% of post-industrial warming was caused by anthropogenic forcing, with only 7% attributable to the sun in “error”? If so, what is a better estimate in your opinion?
Is the IPCC estimate in ”error” that past forcing from all other anthropogenic factors cancel one another out so that forcing from CO2 = total anthropogenic forcing? If so, what specific mistake do you believe IPCC made here?
Is the IPCC estimate that the CO2/temperature relation is logarithmic at the ranges we are discussing here in “error”? If so, what should the relation be?
These are the questions you must answer if you wish to challenge my post – not silly sidelines or speculations about my “agenda”.
If you find that none of the above are in “error”, then I can well understand that you prefer not to get into a specific discussion of the “science”.
Max
I notice Andy Lacis is posting on the latest Climate Etc. thread. Let me accuse him of being a coward in simply running away from the discussion on this thread, which he started. He simply refuses to addrsss my question of the basis in physics for his claim that “Fortunately, the global warming component, it being tied directly to the growing strength of the terrestrial greenhouse effect, is a uniquely radiative effect that can be addressed independently of the other climate complexities.”
Well, Jim, how would approach the problem.
And what in your mind would constitute ‘the basis in physics’ for being able to separate global climate change into two components: component (1) being the steady increase in global warming as the greenhouse effect intensifies in response to increasing greenhouse gases, and component (2) being the natural variability of the climate system that is there even in the absence of changes in the radiative forcing.
What we have available is a climate model with all kinds of physics formulations and parameterizations that appears capable to reproducing the seasonal and geographic variability of the terrestrial climate system – not perfectly, but with a great deal of similarity. If we run the model without any external forcing (other than the normal diurnal and seasonal changes in solar radiation), the model generated climate does not remain constant (again, aside from the normal diurnal and seasonal changes), but it exhibits random looking interannual variability that is similar to what the real climate system does. We can’t make it go away or control it in any significant way. It seems to be the ‘natural (unforced) variability’ of the climate model.
If we now start changing the amount of greenhouse gases in the model, the model’s response is an increase in global temperature. The model’s response is slow, and not instantaneous, because of the large heat capacity of the ocean. That is the global warming component of the climate system response, which is superimposed on top of the natural variability component.
An important question might be to wonder if the nature of the ‘natural variability’ component is in anyway altered by the fact that the global warming component is changing the global temperature. We don’t see much a change in the behavior of the natural variability component as global temperature changes, suggesting that the two effects, to first order, appear to be linearly addable.
That is my perspective and the basis for suggesting that we can separate global climate change into the two components. The global warming component, the physics of which we understand quite well, and the natural (unforced) variability component that accounts for most all of the climate uncertainty that we see in the climate system.
Andrew Lacis
The earth has considerable natural variability. Would you say the effect of more Co2 has introduced an increase in temperature that now puts us above the limits of this natural variability?
tonyb
That is usually the case, as whenever a max increases, the variance increases along with it. In other words, an amplifier will increase the signal along with any noise fluctuation.The magnitude of this fluctuation is a different issue.
Dr. Lacis,
Without trying to disrupt the current discussion, linear enough to be addable is a little questionable. The small change in total forcing by CO2 is roughly a second order effect. That could easily cause uncertainty. What other second order effects may need to be considered? Perviously, you stated the models show a 1.2 degree warming, I assume at the tropopause. Co2 and CH4 have small impacts on the conductivity of mixed gases as does water vapor. Is change in conductivity really negliable? Or how is it considered in the models?
I know this is in ice, not air, but there is a change.
http://www.chem.hope.edu/~polik/warming/IceCore/IceCore2.html
Dr. Lacis
You ask Jim how one should approach the problem of how “to separate global climate change into two components: component (1) being the steady increase in global warming as the greenhouse effect intensifies in response to increasing greenhouse gases, and component (2) being the natural variability of the climate system”
One could start with the physically observed data from 1850 to date on global temperature (HadCRUT3) and atmospheric CO2 (IPCC and Mauna Loa), as I have suggested in an earlier post.
Then one can take the IPCC estimates of the relative importance of past natural forcing to anthropogenic forcing, specifically from CO2, or the estimates of several independent solar studies.
Based on the actual physical data plus the assumptions on natural versus anthropogenic forcing, one can arrive at the climate impact of increased CO2 levels.
One can then attempt to find data on the magnitude of the entire fossil fuel resource of our planet (fortunately the WEC has published a 2010 report, which gives data on the “proven fossil fuel reserves” as well as the “inferred possible total fossil fuel resources in place”.
Taking these estimates and the observation that around 50% of the emitted CO2 “stays” in the atmosphere, we can roughly estimate the highest possible atmospheric CO2 concentration resulting from human fossil fuel emissions – this turns out to be around 1,065 ppmv.
With this rough estimate and the observed CO2/temperature response, we can estimate the possible future GH warming caused by human CO2. This comes out around 2.2 degreesC.
The big unknown here IMO is NOT what long-term warming we could expect from CO2 (as this seems to be constrained, as indicated), but rather what changes can we expect from changes in natural forcing (or natural variability).
(As we have seen over the past decade, these can overshadow the GH warming effect from CO2.)
If you have time, I would appreciate your comment on all this.
Max
Andy Lacis writes “Well, Jim, how would approach the problem.”
Again thank you for your reply, which I am not sure I understand It seems you are talking about two components; the greenhouse gas component, and a natural variability component. That is not somethiong that I had considered. I was looking at the problem from a completely different point of view. There are four ways in which energy is transmitted through the atmosphere, namely conduction, convection, radiation, and the latent heat of water. I took your claim that we only need to look at the radiative component as a claim that we do not need to consider the other three ways that energy is transmitted. If all you are claiming is that natural variability and greenhouse gas effects can be seperated, I suspect you are correct.
But as I read the ways in which climate sensitivity is estimated, these only include radiative effects; they ignore conduction, convection and the latent heat of water. I see absolutley no reason to believe that such estimations have any basis in the physics of the way the atmosphere works. And this was the way in which I misinterpreted what you were claiming.
Jim,
One other thing to keep in mind (I am sure I have mentioned it here somewhere before) in separating the global warming component from the natural variability component is that the global warming component is a globally averaged annual mean radiative flux quantity. This point is important because the (horizontally) advected latent heat, sensible heat, and geopotential energy fluxes (each of which is geographically variable and can be an order of magnitude lager than the local radiation energy) must by definition add to zero in a global average. This greatly simplifies the thinking about the global energy balance since radiation is the only remaining energy transport that needs to be explicitly considered. (There is no latent, sensible, or geopotential energy being emitted to space.) Radiation is something that can be calculated very accurately, given the atmospheric temperature and absorber distributions. And that is what defines the global energy balance and also the strength of the greenhouse effect. This energy balance simplicity that works for the global energy balance, is not applicable at local geographic points where the advected energy fluxes are large and variable.
Energy transport by conduction is very inefficient in the atmosphere and can be safely neglected. Convection is a fast local energy transport process that in climate modeling is typically accounted for by simply readjusting the atmospheric temperature profile (allowing the convection to take place and registering its immediate effect on the atmospheric temperature profile). The atmospheric radiation calculation incorporate the effect of convection, being as the radiative fluxes are determined as the combined result of the atmospheric temperature profile and the vertical distribution of the radiatively active constituents.
Again, Andy, thank you for the reply. By this time, I am well out of my depth, but my instinct tells me that I am not wrong. What I think is happening is that you are describing what is going on the the models, and I am trying to understand what is happening in the real atmosphere. For example, you say “Convection is a fast local energy transport process that in climate modeling is typically accounted for by simply readjusting the atmospheric temperature profile (allowing the convection to take place and registering its immediate effect on the atmospheric temperature profile).” Fair enough, but does this, in fact, account for the way convection works in the real world?
Again, you state ” This greatly simplifies the thinking about the global energy balance since radiation is the only remaining energy transport that needs to be explicitly considered. (There is no latent, sensible, or geopotential energy being emitted to space.)” My impression is that while all the energy that is lost by the earth occurs from radiation, the way this energy is transported by the atmosphere to the places where it is radiated into space, is by the processes other than radiation.
I do wish there was a reference where I could read up, at leisure, the background reasoning as to why it is completely logical to neglect conduction, convection and the latent heat of water, in predicting what will happen when more CO2 is added to the atmosphere. For me to try and understand what you are saying, even on a technical blog, is very difficult indeed.
Actually Dr. Lacis’ great explanation undersells the error in Jim’s post.
Estimations of the global climate response to CO2 perturbations (with a correct conceptual framework) in a radiative-convective model were first done over 40 years ago by Manabe and others, and the impacts of latent heating, etc are now all well understood to be important. In equilibrium, both the top and bottom of atmosphere energy budgets must be satisfied, and changes in evaporation/sensible heating are all associated with a changing climate and included in the final result of what we call a “climate sensitivity estimate.” In fact, it is the non-linearity in the latent heat release associated with water vapor that ultimately gives rise to an important negative feedback (called the lapse rate feedback, which offsets some of the water vapor feedback).
However, in the global mean, the top of atmosphere energy budget exerts a stronger role on the surface temperature than the surface forcing, and the TOA energy budget can be treated as being purely radiative for Earth-like planets. In GCM’s, this is treated at each grid point on Earth with the appropriate absorber and temperature structure, and with dynamical processes included, but even in a simple back of envelope model the tropospheric temperature structure is well constrained by convection to stay rather close to a family of curves called the moist or dry adiabat. Thus temperature anomalies are well-mixed throughout the convecting atmosphere, and the problem of adding CO2 can be treated in terms of reducing the outgoing radiation (at fixed T) and requiring the whole troposphere to warm. The principle effect of the surface energy budget terms (much of which is non-radiative) is to control the temperature difference between the surface and overlying air column.
Chris you write “Actually Dr. Lacis’ great explanation undersells the error in Jim’s post.”
I am lost. What was the error in my post? I am nogt aware that I have made ANY error.
Jim Cripwell
I don’t know if Andrew Lacis is escaping a continued discussion on this thread because he fears he would not do too well in such a discussion or if he is simply too busy with other things.
I have just observed that a couple of posters here have taken issue with my post, which suggested, based on actual observed CO2/temperature data from 1850 to today plus IPCC estimates of natural versus CO2 forcing, that there is not much to worry about regarding future AGW.
Yet there were no rebuttals to specific points: neither the bases nor the calculation itself were challenged.
Possibly this is the same escape reaction you are getting from Dr. Lacis.
It appears that catastrophic AGW proponents are a bit allergic to empirical data based on actual physical observations, preferring the virtual world of model simulations, instead.
I wonder why?
Max.
“Yet there were no rebuttals to specific points: neither the bases nor the calculation itself were challenged.”
But what’s the point with you? Even when its shown your figures are clearly wrong you wait a month or so then regurgitate them all again somewhere else.
Those who dismiss AGW as a hoax aren’t generally taken that seriously.
tempterrain
Sorry, tt.
No one has as yet “shown the figures are clearly wrong”.
And these figures do not purport to show that“AGW :is a hoax”, tt; simply that it is nothing to get alarmed by.
Please show me where “the figures are clearly wrong”, if you can.
Max
The paper discussed in this thread is not about climate sensitivity on the increase of CO2 over the last 100 years or in the future. It presents a model experiment on, what happens, when noncondensing GHG’s (NCGHG’s) are removed in total. It’s pointless to argue on that based on any observations concerning any historical period, because nothing like the total removal has ever happened or will ever happen. That means also that the paper provides no new insight on the future.
The paper is trying to explain the full significance of the NCGHG’s for the Earth climate hoping presumably that such an explanation would be helpful for those, who haven’t understood the basic physics, but are still willing to learn more. It’s a little less extreme counterfactual exercise than the case discussed in a couple of threads here, where it was asked, what happens, when no GHG’s exist at all, not even H2O making the atmosphere fully transparent to IR.
The basic result that removing NCGHG’s will lead to such a reduction in H2O in the atmosphere that the remaining GHE is very weak, is easy to anticipate. Thus it was possible to guess much of the results, but certainly not all. Another question is, haw far those results are model dependent and unreliable that could not be anticipated. Should we believe that the annual mean surface temperature at equator stays above 0C, or should we expect that it falls below that value? Neither it’s obvious that the total water vapor stays close to 10% or the cloud cover near 75%. These specific numbers may be model dependent for a model that has never been developed to work under the resulting conditions.
All-in-all the calculation is an intellectually interesting exercise that may help some people in gaining further understanding on the basics, but it is not a contribution towards more accurate or reliable knowledge on the future climate.
As a side comment I must say that I’m uncomfortable with statements on the percentage shares of various GHG’s in GHE. The numbers can be defined in several different ways, none of which is intuitively clear. I’m fully confident that removing all NCGHG’s would make to total GHE very weak. In that sense they are almost 100% of the whole. Some other justifiable definition could give a value of significantly less than 10%. Neither of these makes sense, and nothing in between has an unique value as a right choice either. None of these values has scientific significance or is of help in decision making. They are just numbers thrown to the public debate in belief that they may influence the outcome of the debate.
From the point of view of science the paper falls to the category “nice to know”. As far as I can judge it was written and published by Science having the public debate in mind rather than as a scientifically new and important contribution. That may be appropriate for a publication of AAAS, while it might not fit as well the profile of some other scientific journals.
Pekka Pirilä
You wrote:
adding
Yes, Pekka. I would agree. The paper itself is purely hypothetical. Using model simulations and theoretical deliberations to hypothesize on what might happen to global temperature if CO2 were removed from our atmosphere, concluding:
But the title of the paper gives us a hint where the author is taking us, as Dr. Curry points out in her lead-in to the earlier CO2 “control knob” thread:
The purely theoretical “with/without CO2” deliberation is interesting but, in the practical sense, it has been shown to be small in the range that is physically possible to attain, based on fossil fuel carbon availability.
I simply showed that the premise of a “CO2 climate control knob”, which will play a principal role for the climate of the next 150 years or sois not borne out by actually observed climate record of the past 160+ years (since the modern record started).
In other words, the physical data show that CO2 is a “mini-control knob” in the practical sense, even though it could arguably have been a more important factor in our past climate, if the conclusions Dr. Lacis draws from his model simulations are correct.
That was my point.
Do you understand it now, Pekka?
Max
Max,
I find it unfortunate that no thread can concentrate on the original topic, not because each topic needs it’s own space, but because the logic gets difficult to follow.
My view is than concerning the Science paper, it’s important to understand, how limited it is, and that it in particular is not about climate sensitivity. When that’s understood, discussion of climate sensitivity should not be brought to this thread.
What has happened is, however, that a connection between the correctness of the paper and estimates on climate sensitivity is assumed. The paper is attacked based on such a assumed connection and the paper may be somehow imagined to give support for the mainstream estimates of climate sensitivity. Such assumed connections are not true and comments based on them are only adding to confusion.
I have discussed issues related to climate sensitivity elsewhere and continue that elsewhere.
When the exercise is understood correctly and when it’s understood that its qualitative results could be anticipated without the model calculations, the exercise could serve as a tool in trying to get people to understand how the extreme dragon slayers are wrong, but not as an argument against those more sophisticated skeptical views that maintain that the feedbacks may be weak for the present and foreseeable future climate. I consider it always good, when even a few more people can accept and understand the nature of the basic mechanisms, whatever they think about the less obvious quantitative results of the climate science. The potential role of this paper is in explaining the present level of the GHE and the importance of CO2 for that, rather than in supporting estimates on, how the GHE will change with more CO2.
Are temperature trends of the past century consistent with the expected effects of CO2? An interesting discussion upthread between Max Manacker and Jim D entailed the estimated consequences of CO2-mediated forcing and temperature trends over the twentieth century. I inferred from the discussion that Max was looking at the temperature response in terms of equilibrium climate sensitivity (ECS) estimates, but the problem with this is that temperature responses to forcings take time to develop and so their magnitude at early time intervals will be less than later and still less than at equilibrium many centuries hence. Max used IPCC forcing estimates to state that total net anthropogenic forcing is more or less equivalent to CO2-mediated forcing at about 1.6 W/m^2 since 1750 because other positive and negative forcings cancelled out. Could this account for much of the temperature trend of the past century (about 0.8 deg C since 1910 in the GISS record)?
Well, the answer seems to be that it could not if those 1.6 W/m^2 had been the forcing magnitude ever since 1750. However, it turns out that most of the 1.6 W/m^2 did not develop until fairly recent decades, and when the time element is factored in, the temperature response is more or less what would be predicted from climate sensitivity estimates.
In this regard, studies on Transient Climate Sensitivity (TCS) and the very similar concept of Transient Climate Response (TCR) are informative, as discussed in the thread on Probabilistic Estimates of Transient Climate Sensitivity. These studies used simple energy balance models involving the radiative response to surface temperature combined with ocean heat uptake to estimate a parameter from twentieth century forcing data relating forcing to temperature response. Using the TCR terminology, the parameter is ρ, where ΔT = F/ρ, and with ρ having typical values of about 2 to 2.6 W/m^2/K. From these estimates, the 2xCO2 TCS was estimated to range between 1.3 and 2.6 deg C, while the 2xCO2 TCR ranged from 1.3 to 2.3 deg C, and is consistent with much of the observed 0.8 C rise having been the result of the gradual rise in forcing magnitude to the late century value of 1.6 W/m^2. These can’t be directly translated into ECS estimates, but given the temperature trajectories in many GCM models, the results fit well with the standard ECS estimates of 2 to 4.5 C for doubled CO2. The concordance is reassuring for confidence in this general range of sensitivity values derived from very different approaches.
Figure 5 in the TCR paper demonstrates how recently forcing grew to current estimates, and why it is not surprising that the temperature response is still in its earlier stages. Much of the early twentieth century forcing represented a combination of anthropogenic greenhouse gases, solar forcing, and a reduction in volcanic aerosols from early in the century toward mid-century. The late century forcing was primarily anthropogenic, as has been discussed elsewhere as well.
Fred Moolten
No, Fred.
I have not tried to differentiate between “transient” and “equilibrium” climate sensitivity. These are interesting theoretical concepts, which have, as yet, not.been corroborated or quantified by any empirical data.
I have simply taken the physically observed data from the past 160+ years and projected it to the next 150 years or so, using IPCC assumptions on past forcing from natural components, aerosols, other GHGs and CO2 and published values from WEC on the amount of fossil fuel resources that might possibly be available on our planet.
These data have suggested that the temperature response to the CO2 resulting from combustion of all the optimistically estimated fossil fuels on our planet is around 2 degrees C.
IOW, CO2 is not the “primary climate control knob” in a practical sense today (even though it may have played a major theoretical role, as Dr. Lacis’ model simulations appear to suggest).
I hope you can see the difference here, Fred. It is the dichotomy between empirical observations and hypothetical deliberations as bases for future projections.
Max
Manacker is a mere trendologist who also happens to publish obviously bad data in the name of his research. See this unfortunate incident that caused me some grief for an important analysis I was working on:
http://judithcurry.com/2011/09/06/detection-of-global-economic-fluctuations-in-the-atmospheric-co2-record/#comment-112224
I have yet to see a retraction from Manacker for that carelessness.
My opinion is to watch out for these people that deal only with data.
Manacker’s musings on fossil fuel resources are a good example of this trendology. Simply using trends fails badly for estimating ultimate resources, as an underlying model is required to get away from the naive dead-reckoning predictions. The fact remains that to get at these more abundant lower-grades of fossil fuels, any trending approaches will vastly undershoot how much extra energy we will need to expend to achieve future positive returns.
There has been much talk here recently on positive feedbacks, and so I will give an example of a real positive feedback. Consider the huge positive feedback energy cycle that goes into using significant amounts of natural gas to separate the oil from the tar sands. You put in energy to get back energy but the energy returned is so meager because you have to use much of that energy to create the energy
dNetEnergy = dE – dEnergyUsed
dEnergyUsed = k*dE
dNetEnergy = (1-k)*dE
or
E = NetEnergy/(1-k)
as k gets closer and closer to unity we have the situation where we are multiplying our usage of energy by a 1/(1-k) factor, which is essentially a positive feedback. During the early 1900’s in oil-boom America, the value of k was essentially close to zero, but ever since then the value of k has declined, and now many of the contingency sources are closer to 1, with some of these, perhaps including biofuels actually breaking through that value and providing NO net energy gain. This is basically using energy (natural gas to create the fertilizer and oil to drive the tractors) to release CO2 in the air for no net benefit apart from shifting money around.
This kind of positive feedback is the same thing that the climate skeptics like to be skeptical about when it comes to atmospheric feedbacks. And so what do you know, they will likely ignore it when it comes to estimating fossil fuel usage as well.
The odds are that civilization will rather cook in its own juices to extract fossil fuel energy from whatever sources we have, simply because we don’t have a lot of other choices. Not surprising that the majority of those same skeptics are against green energy solutions. Of course renewable energy solutions also don’t have a great energy return but the thinking is that less carbon-based energy is used during the feedback cycle.
Geez, I am thinking I can publish this comment over and over and over again, just like Manacker and Girma and all these other commenteers like to do with their accompanying model-free trendology.
I’ve recently tended to be harsh on Max Manacker for conclusions that are clearly in error. However, many participants make inaccurate claims. My concern about Max is that his claims are associated with a great deal of arithmetic, which gives them a spurious air of authenticity. That is why I earlier warned casual readers that taking his comments seriously was a hazardous choice.
In the particular case above, I explained why “trends” in temperature since 1850 can’t be extrapolated to future consequences of anthropogenic forcing, because a large part of the latter did not develop until the last several decades, and so the climate response is just starting. In light of this information, there is no physical meaning to be derived from the arithmetic he cites. I indicated that the TCS and TCR estimates, based on simple energy balance models in combination with observed data, indicate that a CO2 doubling would raise temperatures over this century by somewhere between 1.3 and 2.6 C, with further rises after that. This is consistent with equilibrium sensitivity ranges of 2 to 4.5 C from studies that include the more complex GCMs. However, these figures by themselves may not completely define the issue for several reasons..
In estimates of the consequences of continued anthropogenic GHG emissions, some adverse consequences have been predicted for a CO2 doubling from the baseline preindustrial concentrations of about 280 ppm, and for a temperature rise exceedimg 2C above the temperatures at the beginning of the twentieth century. The extent of those dangers is a topic for discussion elsewhere, but the point is that CO2 doubling and temperature rise must be related to a particular baseline, and a current baseline of about 390 ppm following a temperature rise of about 0.8 C arbitrarily subtracts from some of the effects already underway.
Regardless of baseline, a rise of CO2 to about 1065 ppm would exceed a doubling and constitute something closer to a tripling or exceeding it depending on where one starts. Any TCS/TCR estimates would have to be adjusted upward to account for this.
However, those estimate assume a starting point with the climate in radiative balance. With a current radiative imbalance, the forcing will be greater because the existing imbalance must be added in.
Finally, it is expected that the cooling effect of industrial aerosols will not keep pace with rising CO2 emissions, and may even decline. This is uncertain, but could add another 1 W/m^2 to the net forcing over the remainder of the century. Obviously, there are uncertainties associated with all these estimates, but they operate in both directions. The actual warming might turn out be well tolerable, but it could also exceed 4C from the higher end of all the estimates. A figure beyond that is conceivable from the triggering of “tipping points” such as massive methane releases, but a magnitude and probability for that event is too conjectural to warrant a definitive set of values.
Fred Moolten
I must admit that you have a real talent. You have just posted 500 eloquent words (2500 characters) without saying much of anything.
The CO2 increase we have seen from 1850 to today has been from 290 to 390 ppmv. If we accept the IPCC assumptions on past natural versus anthropogenic forcing, approx 93% of the 0.7°C observed warming over this period can be attributed to CO2 = 0.65°C. There have been no demonstrated adverse effects up to now from this minimal amount of warming (and, quite possibly, some beneficial effects).
Using the logarithmic relation, this gives us a calculated 2xCO2 impact (780 ppmv) of around 1.5°C and a maximum possible warming when all fossil fuels are used up (1,065 ppmv) of 2.2°C above today.
You write:
That is precisely what I just did, Fred.
Max
Fred Moolten
To the four points you made to refute my observation that actual CO2/temperature data do no support the notion of ararming GH warming from human-induced CO2:
1.Starting with today as a baseline is wrong. We must start with year 1750.
Wrong. There is no evidence that the “ideal” global climate was in 1750 (rather than today). In fact, there are many indications that just the opposite is true. So “today” is a good “baseline” point.
2. The observed data do not take into account energy “hidden in the pipeline”.
This postulation by Hansen et al. is based on circular logic, as you even point out above:
http://pubs.giss.nasa.gov/docs/2005/2005_Hansen_etal_1.pdf
Translation: “Our models tell us we should have seen twice the warming that we have actually observed, and since our models cannot possibly be wrong, there must be an equivalent amount of warming still hidden ‘in the pipeline’”.
Sorry: no sale.
3. Industrial aerosols may be less important than in the past, and this could make things even worse.
Duh!
4. How about methane clathrates, just lurking up there to pop out and fry us all (when the globe is 2°C warmer than today)?
Ouch!
Max
Max, The problem is really quite simple, as I am sure you are aware. Many years ago, the proponents of CAGW estimated some numbers which, they claim, show that disasterous CAGW will occur. Now we have many years of actual, hard, measured data, which simply show that the estimated numbers are wrong. So, in order to still maintain that CAGW is happening, the warmists need to try and maintain that their original numbers are still correct. They do this by claiming that the way the hard data is being interpreted is wrong. However, what thay cannot do is to show what is the “right” way of interpreting the hard data. They dare not compare their estimated numbers with what is actually happening. Fred Moolton tries to show you where your numbers are wrong, but he deliberately avoids showing the “right” way of interpreting the numbers. Because there is no way of showing that the actual data agrees with the original estimates.
Max – Few may be reading these exchanges at this point, so I don’t want to prolong them unduly. I believe readers who visit the recent exchanges will understand my points, and can compare them with your statements to make their own judgments. In my view, your latest comments only repeat what you said before, including the errors, with the only difference being that you have included an additional mistake – your misunderstanding of the concept of the “piipeline”, which does not refer to differences between modeled and observed results. Regardless of whether a particular model reproduced observations exactly or was off by some factor, the “pipeline” warming would exist in either case, because the heat within it is currently encompassed within the structure of the sun and is not “hidden” in the climate system. It hasn’t reached Earth yet.
The Crip is so fascinated by his data even though any control engineer worth his weight knows that the model is extremely important. Great if the measurement and the data has so little inertia that a control algorithm can immediately adapt to a change in the data stream and thus avoid disaster. Yet we know in climate science that the CO2 has a huge amount of inertia in the atmosphere, and any control we exert has to take this model into account.
It is very similar to the big tankers in the ocean which have to start decelerating far from port because they can’t stop on a dime. That’s OK if the Crip and the Max want to go on with their head in the sands and blithely ignore the implications of modeling that inertia and what’s in the pipeline.
Fred
Let’s cap this off. You state
Exactly my sentiments, Fred.
See you later,
Max
Webhubtelescope writes “My opinion is to watch out for these people that deal only with data.”
I plead guilty as charged. I am only interested in hard, observed, measured data. I would put it the other way reound. Watch out for those people who seem to think that hypothetical numbers are more representative of the real world that actual measured data.
Jim Cripwell
You refer to the comment by WebHubTelescope:
And then add your response:
I’d have to agree with you .
This is the problem we are witnessing here with many of those who (want to) fear alarming GH warming from human CO2 emissions, when the “data” tell them this fear is unfounded.
Max
WHT
You write erroneously:
This is not my curve, WHT, as I pointed out already once.
I simply compared the HadCRUT3 data (change from previous year) with the % of the CO2 emitted to that “remaining in the atmosphere”.
Somebody else made an incorrect curve – dunno who (could it have been YOU?)
Max
You know what you did, weasel. You put in a bad data point for the fossil fuel emissions data for the year 1988.
http://farm7.static.flickr.com/6088/6125488794_8ef0233067_b.jpg
I had to transcribe the data and plot it to see the bad data point.
Take responsibility for your actions Max. In your original post comment you didn’t attribute it to anyone, so you own it:
http://judithcurry.com/2011/09/06/detection-of-global-economic-fluctuations-in-the-atmospheric-co2-record/#comment-110093
Unless you want to be known as a plagiarist as well.
Bad data from Manacker highlighted here:
http://img171.imageshack.us/img171/5334/manackersdata.gif
He took data from the ORNL Carbon Dioxide Information Aanalysis Center and stuck in a bad number for CO2 emissions in 1988.
The original data is here:
http://cdiac.ornl.gov/ftp/ndp030/global.1751_2008.ems
Painfully obvious
WHT
No need to get your knickers all twisted out of shape.
I went back to look at the data sources to my calculation and curve comparing atmospheric CO2 increase as a % of human CO2 emissions plotted against change in global temperature over previous year to see if I could find the data point error you spotted for the year 1988.
I found the error.
I had entered 5.060 GtC to the spreadsheet where the actual number was 5.960 GtC.
This has been corrected on the attached table and graph.
http://farm7.static.flickr.com/6168/6254754231_a4b6bfeeb1_b.jpg
http://farm7.static.flickr.com/6053/6254767203_b86c543a31_b.jpg
It does not change much overall, but thanks for finding the error.
Max
Good that you finally admitted it, but you should realize that a single data point can really screw up cross-correlations when the size of the data set is that limited.
Now go back and realize how much you are inferring from the limited data we have from recent history. Statistical uncertainty arising from limited sets of data does not benefit either camp, it exists and we have to deal with it in other ways — modeling of the physics from first principles is one such approach.
WHT
The one data point has been corrected. Thanks again for your input.
The apparent correlation between the %-age of the emitted CO2 “remaining” in the atmosphere on one hand and the change in global temperature from the previous year appears not to have changed because of the correction of this single data point.
Years with a warming trend showed higher % than those with a cooling trend.
This was just a very simple analysis, WHT.
I’ll leave it to someone else to see whether or not this all means anything and why.
Max
Andy Lacis writes “Energy transport by conduction is very inefficient in the atmosphere and can be safely neglected.”
I find this hard to believe. Over land, on a warm summer day, there are often lots of fair weather cumulus clouds. These form when the land heats the air, BY CONDUCTION, and thermals are formed.
In any event, this is the sort of sloppy way of writing that seems to be typical of warmists. I am not an expert in climate science. When I worked, I was an expert on some subjects, and for those subjects, I kept a detailed record of the numbers which were important. So if I needed to make the sort of claim that you have made, Andy, I would NEVER have couched it in those terms. My response would have been something more like “Data shows that the proportion of the energy that leaves the earth an enters the atmosphere by conduction, convection, radiation and the latent heat of water is
Conduction a%
Convection b%
radiation c%
Latent heat of water d&
Reference Joe blow, 1988, some paper or other, pp xx to yy.
When one gets that sort of response, then one can be reasonably sure that the author knows what he/she is talking about. Vague words like “efficient” do not inspire confidence.
What are you some sort of moron? Do you understand why we use double-paned windows? Air does not conduct heat well. Sure it convects heat but that is not conduction.
I have had it with all the idiots on this site.
WebHubTelescope wrfites “What are you some sort of moron? ”
You have gone out of your way to deliberately insult me. That I do not appreciate, and if you were a gentleman, you would apologise. No, I am not some sort of a moron. The earth transfers a significant amount of heat to the atmosphere by conduction. see
http://www.atmos.illinois.edu/earths_atmosphere/heat_transfer.html
“It turns out that air is an extremely poor conductor of heat. Therefore, conduction is only important in the atmosphere within the first several millimeters closest to the surface.”
Crip, you lack any kind of intuition or grasp of physics, without any reading comprehension to boot. You link to a site that states precisely what I said, in particular that air is an extremely poor conductor of heat, and use that as a defense to how I insulted you.
We have a few guys like Fred, Pikka, Vaughan who provide some juice and after that, nada/zilch when it comes to saying anything useful or edifying.
What about convection? IMO you folks are talking past each other.
WHT
“moron”?
“idiots”?
You definitely need to polish up your act, WHT, you are beginning to sound like an insolent adolescent to me
Max
You can use the Kiehl-Trenberth energy diagram to do this budget at the surface.
Incoming solar energy is 161 W/m2 balanced by
Thermals (conduction): 17
Latent heat flux (evaporation): 80
Net longwave radiation (upwards minus downwards): 63
Convection is a process that takes place above the ground, so it is not included in the ground budget above.
WHT, conduction occurs in the lowest millimeter of the atmosphere, but is unimportant away from the land interface. I would give Jim Cripwell some slack on this point.
The minute the air moves it is considered convection, so rising thermals are considered a convective motion.
No slack for the slacker I am afraid.
Jim D,
Themals is convection.
Thermals, sorry.
Yes, the convection starts from above the ground, but first the heat has to be conducted to the air from the ground, which is why I don’t distinguish them.
Andy Lacis writes “Energy transport by conduction is very inefficient in the atmosphere and can be safely neglected.”
Without conduction in the atmosphere the claimed greenhouse effect is not even possible.
When a CO2 molecule absorbs a 15um photon it is most likely to lose this energy by collision with N2 and O2.
This causes a local temperature rise.
Only conductive transfer covers this process.
If as Andy says we can ignore this then we can ignore the greenhouse effect.
Suits me !!!!
Good point. Thermalization at normal atmospheric densities is such a fast and short-range process that it is taken to be instantaneous, which is why it is often forgotten.
Drawing lines on, what’s conduction and what’s not is not well defined on microscopic level. If all energy transfer that involves only molecular kinetic energy and collisions is included, conduction is essential in maintaining the local thermal equilibrium, but equally well may one count as conduction only processes that operate over distances that are significantly larger than the mean free path of molecules. With this other way of defining conduction, it’s of little significance in the atmosphere off from the surface.
Absorption of a 15 um photon adds as much energy as one or two molecules have on the average as kinetic and rotational energy. Thus only a few collisions are needed to get back to local thermal equilibrium without significant increase in local temperature.
At the surface conduction has somewhat more significance, but my intuition tells me that the radiative energy transfer is often more important in transferring energy from a hot surface to the lowest atmosphere, but relative importance of conduction and radiative energy transfer varies depending on the particular conditions like windiness. A large temperature difference may make the conduction more important as it will bring the onset of convection closer to the surface. Evaporation and related transfer of latent energy is also certainly very important under most conditions.
Pekka, clear-sky radiative warming from surface radiation is very weak because the atmosphere absorbs only inefficiently. One way to see this is to take the global average 390 W/m2 from the surface and 240 W/m2 out from the top of atmosphere (I know this includes clouds, but these numbers are an upper limit in that sense for clear sky). This means 150 W/m2 is absorbed by the atmospheric column. This is 150/1e4 W/kg (1e4 kg air in a column). Dividing by the heat capacity (1004 J/kg/K) you get a warming rate of not much more than 1 degree per day.
Jim,
A significant amount of the emission from the surface is absorbed within the lowest 10 meters by CO2 alone. That happens only over a very limited range of wavelengths near 15 um but even so that is a rather efficient form of energy transfer. The net energy transfer due to that mechanism is proportional to to the temperature difference between the surface and the lowest tens of meters of atmosphere.
Pekka, yes, the 15 micron band is absorbed in a short distance, but that only accounts for a small percentage of the total, leading to not much actual heating even including the water vapor bands. You can do these calculations with MODTRAN. Looking down from 1 km, there is about 10 W/m2 less than looking down at the surface. Absorbing this in 1 km is still only 1 degree per day.
Jim,
That’s not the right way of estimating the strength of this mechanism. What should be done is to compare energy transfer near surface for some specific temperature profiles of the near surface layers.
The actual question is, what’s the share of each mechanism with a realistic lowest atmosphere. The share of conduction depends on the temperature gradient of a very thin layer of the order of millimeters, or somewhat more, if it takes more to get convection going, while the radiative transfer that I mentioned depends on the profile over several meters or tens of meters. This difference makes guesswork difficult, but some information on the relevant profiles should be available.
Pekka, I would argue that conduction and convection transfer heat by one route and radiation by an independent one that runs in parallel. It doesn’t happen that radiation transfers heat to low levels with enough preference to produce convective instability. It distributes the heat too uniformly in the column.
Jim,
With radiative heat transfer alone the GHE would be about twice as strong, which means that your statement is simply wrong. Here we reach a point that you must know already, although didn’t realize it.
On stoichiometry.
Some argue the rise of CO2 corellated earlier rise in temperature as seen in the ice core record or other paleo measures weakens the proof of AGW by lessening the evidence of the GHG effect, or lessens evidence of anthropogenic influence, or makes more uncertain the relationships of land use vs. CO2 emission.
Stoichiometry tells us this is nonsensical reasoning, though we are not looking at stoichiometry in the case of the control knob of CO2 on temperature, but rather Henry’s Law (and fugacity) balanced against the Tyndall effect for IR in CO2, and not chemical equilibrium but solubility connected to the GHG mechanism.
In stoichiometry, exothermic reactions do lead to heat rising; however those reactions have pressure exerted on their direction depending on heat; in other words, the control knob itself is reactive to what it controls, teeter-totter like.
The same applies to solubility. Just as heat drives CO2 out of solution in water (or ice or soil),
People of a certain age may remember when keyboards were reactive, the rise and fall of each key balancing the fall and rise of each striker.
Steam engines with regulators drive the regulators to spin more and more rapidly; the rapidly spinning regulators limit the power of the steam engines.
Were an outside hand to spin the regulator, the engine would be as overcontrolled as if it had achieved that higher power level.
So the evidence for temperature led CO2 changes is evidence for CO2 led temperature change.
Which provides pretty good foundation for anthropogenic climate change without any modern day data.
The land-use/emission ratio question remains intricate and challenging, however.. but by the same token, it means or strongly implies that higher emissions curtail land use options and makes all land use more costly.
“So the evidence for temperature led CO2 changes is evidence for CO2 led temperature change.”
Strongly disagree.
Edim
I wasn’t presenting opinion, but logic based in fact from evidence.
You’re welcome to have whatever opinion you wish; facts and logic however are not your personal property nor mine; neither you nor I can overthrown them on whim.
Counter fact and logic with logic and fact.
If you can’t, you’re merely wrong.
Bart
The evidence for temperature caused CO2 variation makes significant CO2 caused temperature changes very unlikely, because any small disturbances in both CO2 or temperature would be amplified making the climate system unstable. We know from observations that the system shifts from warming to cooling at the highest CO2 forcing. It never fails and it seems to be happening at the moment.
Edim
I would be very excited to be provided with more details of these statements.
If you mean that over the past 800k years, every time the global CO2 level exceeded 280 ppmv it was followed within a few thousand or tens of thousands of years by a fall in CO2 level to about 180 ppmv.. that would be difficult for us to confirm in less than a few thousand years of observation.. especially as we’re currently above 390 ppmv globally and still heading upwards, an unprecedented circumstance.
Edim and Bart R
In addition to showing a CO2 lag of several centuries behind temperature, the 450,000 year Vostok record shows several instances when CO2 levels were higher than average and temperature began to decline as well as instances when CO2 levels were lower than average and temperature began to rise.
These data do not point to a “CO2 control knob”.
Max
manacker
That the control knobs on CO2 level itself get dialed down after tens of thousands of years is evidence CO2 level is not a control knob of temperature?
Sorry, sport.
You’ve lost me there.
Bart
Sorry you’re “lost”.
Let me help you.
I did not say that the observed “multi-century lag” or “reverse CO2/temperature response” were “evidence CO2 level is not a control knob of temperature”.
But they surely are not “evidence that CO2 IS THE control knob of temperature”.
They show that there is obviously something else at play, which is stronger than the CO2 control knob, that’s all.
Max
manacker
“Something stronger at play?”
There are a great many strong things at play.
The condensing things may be very strong, but like a candle burning brighter, burn out all the sooner.
The Sun will in the far future have the final say, but we have no evidence to support claims the Sun is flexing its muscles in any way related to the control knobs at the current moment.
Ocean currents might move the temperature net up or net down on 2-15 year spans in cycles up to 60ish years, but are too weak to reach beyond the influence of that range.
Once much more than 20 years have passed, the ocean currents are largely irrelevant. CO2 with its 44-year halflife in the carbon cycle, is cumulative effect in the atmosphere, its positive feedbacks is the strong effect overall on timespans of interest to us for policy decisions.
Dr. Lacis: To speed up calculations, GCM’s do not perform radiative transfer calculations using line-by-line methods. Was the ability of GISS ModelE to perform accurate calculations in the absence of CO2 and presence of dramatically less water vapor VALIDATED using LBL methods before the calculations described in this paper were performed? Approximations useful for today’s atmosphere seem unlikely to remain valid for the atmosphere you project, especially those dealing with overlapping absorptions. The apparent inconsistencies estimated below suggest that the dramatic changes you projected for absence of CO2 may not be properly calculated by your GCM.
Several decades after removing all CO2 from the atmosphere, your paper projects that temperature will have declined to -20 degC and water vapor to 10% of current levels. You also project that the albedo will rise to 0.42, giving a Te of -30 degC, leaving a greenhouse effect of only 10 degC. This is about 1/3 of the current greenhouse effect.
Unfortunately, these results aren’t consistent with other values reported in your paper. First, you project that 10% of current water vapor (400 ppm) would be present, an amount comparable to current CO2. The bent structure of water produces many more absorption lines that linear CO2. The dramatically stronger greenhouse effect of water can be illustrated by comparing the radiative forcing for CO2 (3.7 W/m2/doublingCO2) with the feedback for water vapor (2 W/m2/degK). Assuming constant relative humidity, water vapor is expected to increase 7%/degK or roughly double (1.07^10) for +10 degK. 2 W/m2/degK * 10 degK/doublingH2O gives a ballpark estimate of 20 W/m2/doublingH2O. If roughly 20% of the current greenhouse effect is due to carbon dioxide, 400 ppm of water vapor must provide more, perhaps 30% (or even 40%) of the current greenhouse effect. Second, cloudiness (25% of the current greenhouse effect) is predicted to increase from 57% to 75%. Putting all of these numbers together, one might expect the following changes: CO2, 20% to 0%; water vapor, 50% to 30%; clouds 25% to 32%. Using these estimates, the earth would retain about 2/3’s or 22 degC of its current greenhouse effect – twice as much as you projected.
Frank,
Actually the GCM radiation model will reproduce accurately the radiative effects even for extreme distributions of the absorbing gases or clouds. This has been tested off-line against line-by-line calculations for a wide range of extreme atmospheric conditions. Obviously, the model accuracy has been optimized to be most accurate for current atmospheric conditions. The radiation calculations are not a problem.
The same however, cannot be said about model generated cloud properties. There have been far less opportunities to verify what the clouds should be under extreme conditions.
Dr. Lacis: Thanks for your reply, though I do wish you had been more specific than “a wide variety of extreme atmospheric conditions”. For example, calculation of OLR by LBL and GCM methods agreed within X% at several locations at the end of the run.
Did you see any major errors in the “back of the envelop” calculations that suggest that about 2/3 of the current greenhouse effect should have been retained? If the altitude of cloud tops dropped substantially, their greenhouse effect would be much weaker.
I am not sure whether it is much use trying to discuss science on this thread any more. Dr. Curry has done a wonderful job of providing a forum where the two sides of the debate can talk science. But this only works if both sides obey the normal rules of scientific debate. WebHubTelescope hides behind a cowardly nom de plume, while he accuse me, who uses his real name, of being a moron, when all I did was state a scientific truth. He has not responded to my request for an apology. Chris Colose accused me of making an error, but he wont tell me what the error is. Andy Lacis just seems to have just disappeared again. It is all rather disappointing.
Poor Jim.
No one who is qualified is staying around here to do your science homework for you.
So sad.
And surprising too – After all, once you’ve called fellow posters cowards, it behooves them to treat you with utmost respect in supplying you all the answers you require in your quest to achieve personal inner peace.
”
Let me accuse him of being a coward in simply running away from the discussion on this thread, which he started.
”
”
WebHubTelescope hides behind a cowardly nom de plume…
“
For anyonwe interested, Major Tom and I have traded barbs on the CBC blogs in Canada. He does not like me.
I have nothing at all against you personally, Jim. In fact, I used to find your questioning posts on CBC to be well-considered, and often worth responding to.
What I find interesting here is your constant presumption that it is up someone else to cull your personal ‘uncertainty monsters’.
It’s clearly a futile cause. As this thread indicates, even when Dr. Lacis, a real “warmaholic” in your vernacular, with many better things to do, drops by to chat, you cannot resist the tribal urge to say things like “…this is the sort of sloppy way of writing that seems to be typical of warmists.” Followed by, with no hint of irony, “I am not an expert in climate science.”
Dr. Lacis doesn’t owe you the time of day – let alone the sort of “resolution” you seem to think you deserve. Consider yourself lucky to have the occasional hand up from a better qualified climber.
Jim
It is all very well people saying that you and Max have made errors, but it is then incumbent on them to actually illustrate them by providing the ‘correct’ information.
I look frward to seeing if that is forthcoming, otherwise we shall have to draw our own conclusions
tonyb
Precisely.
The problem is going to be keeping the CO2 knob at 500-600 ppm once fossil fuels run out so we can keep a more habitable planet. It’s 390 ppm now which allows us to support 7 billion people.
Kermit
You make an interesting observation. Has anyone postulated an optimum CO2/population relationship? And what role would global temperature play (if any)?
Let’s see:
Major crop yields increased by around 2.4 times from 1970 to 2010.
World population in 1970 was 3.7 billion; in 2010 it was 6.9 billion, so this is an increase of roughly 1.9 times.
Over the same period, atmospheric CO2 rose from 324 ppmv to 390 ppmv or by around 20%.
And the “globally and annually averaged land and sea surface temperature anomaly” rose by 0.46°K, or (taken as a % of absolute temperature) from 288.10°K to 288.56°K or 0.16%.
So the “CO2 control knob” appears to have worked better at improving crop yields than it did at increasing temperature.
Wiki tells us that 6 million died from starvation in 2009 and:
6 million deaths per year out of 6.9 billion = 0.087% today. Although specific numbers are not cited this percentage was estimated to have been more than twice as high in 1970. If it was 0.18%, this would represent 6.7 million deaths out of a much smaller total population.
There were undoubtedly many other factors, beside the higher CO2 levels (and the minimally higher temperatures) that helped increase crop yield and reduce starvation (improved crop seeds, better fertilizers, enhanced irrigation, etc.).
UN projects that world population growth will slow down dramatically, with population leveling off at around 10.5 billion by the end of this century.
What will be the optimum CO2 level (and global temperature) to support this higher population?
It would be interesting to see some real projections on how this will develop in the future (preferably not from a Malthusian “doomsayer” – we’ve seen enough of these predictions, which never come about).
Max
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