How sensitive is global temperature to cumulative CO2 emissions?

by Nic Lewis

The mean carbon cycle behaviour of CMIP5 ESMs and EMICs may be quite unrealistic.

IPCC AR5 states (WG1 SPM E.8) that “Cumulative total emissions of CO2 and global mean surface temperature [GMST] response are approximately linearly related”. The mean increase in GMST with cumulative CO2 emissions simulated by current CMIP5 Earth System Models (ESMs) and EMICs[i] was presented in AR5 (Figure SPM.10; coloured lines) for differing Representative Concentration Pathway scenarios (RCPs).

WGI_AR5_FigSPM-10

Figure SPM.10: Global mean surface temperature increase as a function of cumulative total global CO2 emissions from various lines of evidence. Multi-model results from a hierarchy of climate-carbon cycle models for each RCP until 2100 are shown with coloured lines and decadal means (dots). Some decadal means are indicated for clarity (e.g., 2050 indicating the decade 2041−2050). Model results over the historical period (1860–2010) are indicated in black. The coloured plume illustrates the multi-model spread over the four RCP scenarios and fades with the decreasing number of available models in RCP8.5. The multi-model mean and range simulated by CMIP5 models, forced by a CO2 increase of 1% per year (1% per year CO2 simulations), is given by the thin black line and grey area. For a specific amount of cumulative CO2 emissions, the 1% per year CO2 simulations exhibit lower warming than those driven by RCPs, which include additional non-CO2 drivers. All values are given relative to the 1861−1880 base period. Decadal averages are connected by straight lines

The relationship shown in Figure SPM.10 appears to be accepted at face value by most people involved in considering what emission reductions are required to limit the end-century rise in GMST to 2°C relative to preindustrial. The CMIP5 ESM mean sensitivity of GMST to cumulative CO2 emissions – the transient climate response to cumulative carbon emissions (TCRE) – is 2.4°C/TtC at a 2°C rise from 1870. That is for RCP8.5, but TCRE varies very little between the different RCPs.

But is the mean behaviour of CMIP5 ESMs realistic? AR5 had this to say: “Expert judgement based on the available evidence therefore suggests that the TCRE is likely between 0.8°C to 2.5°C per 1000 PgC,[2] for cumu­lative CO2 emissions less than about 2000 PgC until the time at which temperature peaks.” The 2.4°C/TtC CMIP5 mean is only just below the top of that range.

Observationally-based evidence is thin on the ground, but a recent multimodel attribution study[3] relied upon for the AR5 anthropogenic attribution findings, estimated TCRE by scaling CMIP5 model projections to obtain a best match to observed temperature changes. It estimated a 5–95% range for TCRE of 0.7–2.0°C/TtC, implying that the 2.4°C/TtC CMIP5 mean TCRE is too high, even allowing for its element of warming from non-CO2 forcing. Moreover, that attribution based estimate may be biased upwards, since most CMIP5 models appear to underestimate carbon uptake, particularly for land, and carbon uptake by land and ocean sinks was not constrained to match observations. Estimates of the land carbon sink have been revised up significantly in recent years. Moreover, recent observational estimates[4] of land carbon-climate feedback are lower than in most CMIP5 models.

Unfortunately, the response of biogeochemical systems to projected changes in atmospheric CO2 and climate is currently poorly understood. Inadequate scientific understanding of land and ocean carbon cycles is reflected in CMIP5 ESMs exhibiting great variation in carbon uptake in response to projected changes in atmospheric CO2 concentration and GMST, and hence substantial uncertainty in atmospheric CO2 concentration towards the end of the 21st century. Whilst a few CMIP5 ESMs underestimate the historical increase in atmospheric CO2, most CMIP5 models overestimate it, and their projections of future atmospheric CO2 levels are closely related to their existing bias.[5] The response of the land carbon cycle to anthropogenic CO2 emissions varies enormously between CMIP5 ESMs, with diagnosed carbon-concentration and carbon-climate feedback parameters each varying over the best part of an order of magnitude.[6] CMIP5 ESMs do not even agree on the sign of land carbon uptake over the RCP 2006–2100 projection period.[7] Moreover, it seems that all current models are missing an important process that significantly increases the CO2 fertilisation effect (Sun et al., 2014).[8] The existence of all these problems suggests that the mean carbon cycle behaviour of CMIP5 ESMs and EMICs may be quite unrealistic. Perhaps it would be better at this stage to use much simpler ESMs, with a few key parameters that can be selected so as to match observationally-based estimates of carbon-cycle and climate system behaviour.

With this objective, I have recently developed a simple but physically-consistent ESM, with 2-box climate and ocean carbon sink sub-models. Its ocean carbon-cycle sub-model respects ocean carbonate chemistry and AR5 estimates of surface and deep ocean carbon reservoirs and flows, and its land carbon sink sub-model’s characteristics are consistent with feedback parameter estimates in a recent paper.[9] I select the simple ESM’s key climate, and land and ocean carbon-cycle, sub-model parameters so that its simulated global temperature, heat uptake and carbon-cycle changes since preindustrial best match recent observational estimates, sourced largely from AR5. The CO2 emissions and non-CO2 forcings used to drive the simple ESM are primarily taken from the RCP dataset, but with values modified to conform with the more recent AR5 estimates over 1765-2011.[10] That results in the model having an equilibrium climate sensitivity (ECS) of 1.7°C and a transient climate response (TCR) of a little over 1.35°C.

The below figure – a revised version of one that I prepared for a recent climate science meeting – compares the relation of GMST to cumulative emissions as simulated by the observationally-constrained simple ESM (solid lines) with the mean for CMIP5 models per AR5 (dashed lines). The coloured lines show the relationship for each RCP; the black lines show simulation results up to 2000–09. Decadal mean values are plotted.

Slide1

On all scenarios except RCP8.5, the simple ESM shows a TCRE of ~1.15°C/TtC, just under half that per the CMIP5 multimodel mean. On RCP8.5, the simple model TCRE is slightly higher, approaching 1.4°C/TtC. That TCRE is distorted by the much higher non-CO2 forcing per RCP8.5 compared with all other scenarios (principally due to very pessimistic assumptions in RCP8.5 about methane emissions). When non-CO2 forcings per RCP6.0 are substituted for those per RCP8.5 (resulting in the green line), the TCRE based on RCP8.5 CO2 emissions is the same, 1.15°C/TtC, as for other scenarios. A better estimate of the simple ESM’s pure TCRE, with forcing only from CO2, is ~0.9°C/TtC.

Note:  Units of GtC in the version originally posted have been corrected to TtC [1 TtC= 1000 GtC]

End notes

[1] Earth models of intermediate complexity

[2] 1000 PgC = 1000 GtC

[3] Gillett, NP et al. (2013) Constraining the ratio of global warming to cumulative CO2 emissions using CMIP5 simulations. J. Clim., 26, 6844–6858

[4] e.g., Frank DC, Esper J, Raible CC, Büntgen U, Trouet V, Stocker B, Joos F. 2010 Ensemble reconstruction constraints on the global carbon cycle sensitivity to climate. Nature 463, 527–530.

[5] F M Hoffman et al, 2013. Causes and implications of persistent atmospheric carbon dioxide biases in Earth System Models. J. Geophys. Res. Biogeosci., 119, 141–162

[6] Arora, V K et al., 2013: Carbon–concentration and carbon–climate feedbacks in CMIP5 earth system models. J. Climate, 26, 5289–5314.

[7] Based on RCP data and RCP8.5 scenario projections. P. Friedlingstein et al., 2014. Uncertainties in CMIP5 Climate Projections due to Carbon Cycle Feedbacks. J Climate, 27, 511-526

[8] Sun, Y. et al.,2014. Sun_Impact of mesophyll diffusion on estimated global land CO2 fertilization. PNAS, 111, 15774-15779

[9] Friedlingstein, P (2015) Carbon cycle feedbacks and future climate change. Phil Trans R Soc A.373:20140421

[10] Except for volcanic forcing, where the lower RCP estimates are preferred.

JC note:  As with all guest posts, please keep your comments relevant and civil.

436 responses to “How sensitive is global temperature to cumulative CO2 emissions?

  1. Pingback: How sensitive is global temperature to cumulative CO2 emissions? | Enjeux énergies et environnement

  2. It still looks to me like a pretty healthy rise.

    • But perhaps not an unhealthy rise. But then, these models are incapable of cooling (unlike the earth).

      • As with all guest posts, please keep your comments relevant and civil.

      • Which was mine, uncivil or irrelevant, and how so?

      • The double negative is what got me, ‘not’ and ‘un’.

      • Perhaps I was too brief, Ordvic. Under Nick’s analysis the model still shows some warming, as you noted. But the policy issue is whether there will be dangerous warming, as warming per se may well be beneficial. That was my first point. My second point is that these models are constructed so that they must show some warming if CO2 increases, hence that there is still some warming shown is to be expected. Thus the models ignore the scientific literature suggesting that significant cooling may be coming, especially due to solar effects which the models do not include. So while the earth may cool, the models cannot show that. (Mosher apparently thinks this is either irrelevant or uncivil, but I doubt he understands either concept very well, given his past actions here.)

      • David, yes and the warming or cooling is still not unhealthy or is it?

      • It depends on how big it is, Ordvic. A new ice age would be very unhealthy, but a little cooling might be beneficial, just like a little warming.

    • This analysis, and pretty much all others, first assume that essentially all of the temperature rise in the last 150 years is due to the CO2 rise. Proxy studies (e.g., Moberg 2005, and Loehle 2007) going back even 2000 years show as large or larger variations occur over long time periods (about 1000 years ago for these two sources). Proxy studies (ice cores and ocean bottom cores, etc.) going back over the entire Holocene, show even larger variations over all time scales from years to thousands of years. In fact, it appears the present level is not even average over this time. There were no CO2 drivers for these variations, and the Sun average intensity did not vary much, so why do you have to assume the recent rise is not mainly natural variation from a complex chaotic process? Also how do you account for the flattening over the last 18 years or so?

    • Dr Curry. It may be useful to consider total PAR (400-700nm) radiation over the large forests of the world (C sinks) to enhance sensitivity. Plants will capture CO2 linearly with radiation (limited range) so it is not the same to have a CO2 of 430ppm under 1000um/sqmt/s than at 2000. Most plants would capture twice the amount of CO2 during the brighter conditions.

  3. Nic Lewis,

    You Are a breath of fresh air and your work on climate sensitivity maybe as valuable a contribution as Steve McIntyre’s work in discrediting Michael Mann’s HockeyStick.

    However, all the projections leave me cold because they do not acknowledge, let alone deal with the fact the climate changes abruptly, always has and always will. Given this fact, what I want to know is: on balance, is GHG emissions increasing or reducing the likelihood of catastrophic climate change and recognising that:

    – without out our GHG emissions to date the next abrupt change is much more likely to be a cooling than a warming event
    – Cooling is much more likely to be catastrophic than warming

    I want to see probability distributions of:

    – time to the next abrupt climate change
    – sign of the change (warmer or cooler)
    – rates of change
    – duration of change
    – total amount of the change

    I point to Figure 15: 21 (p391) as examples of abrupt climate changes (in northern latitudes, not global) and particularly the very rapid changed 14,600 years ago and 11.600 years ago:
    http://eprints.maynoothuniversity.ie/1983/1/McCarron.pdf

    Figure 15.21 The stable isotope record (∂18O) from the GRIP ice core (histogram) compared to the record of N.pachyderma a
    planktonic foraminiferan whose presence indicates cold sea temperatures) from ocean sediments (dotted line). High concentrations
    of IRD from the Troll 8903 core are marked with arrows. After Haflidason et al. (1995). The transition times for critical
    lengths of the core were calculated from the sediment accumulation rates by the authors and these gave the following results:
    Transition A: 9 years; Transition B: 25 years; and Transition C: 7 years. Such rapid transitions have been corroborated from the
    recent NGRIP ice core data.

    • The scientific revolution that began with Copernicus’s report of a giant fountain of energy at the center of the solar system in 1543 must continue.

      Four hundred years later the Pope was joined by the winner of WWII in 1945, and modern science was used to hide the Creator & Sustainer of atoms, lives and planets in the solar system.

    • I want to see probability distributions of:

      – time to the next abrupt climate change
      – sign of the change (warmer or cooler)
      – rates of change
      – duration of change
      – total amount of the change

      Plot the data for the Roman and Medieval warm periods along with the data for the cold periods that are always in between. Start the plots with the warming on top of the modern warming and look to our future being the same as before. We have a similar cycle happening again.

    • As with all guest posts, please keep your comments relevant and civil.

  4. THIS is what CAGW is all about.

    • Up market feeding at the trough.

      • I just copped a gander of that spread and I’m putting in for Community Organiser immediately. (The CO in the photo worked tirelessly to make housing affordable, and now you can buy a house in Detroit for the price of that flower arrangement.)

        One should stay on topic, I know, but with COP 21 under way it’s far more important to heap ridicule on the climatariat.

        Heap it, citoyens!

      • Presumably they get it good most days, the topic of conversation is irrelevant.

      • As with all guest posts, please keep your comments relevant and civil.

      • From the “Let them eat windmills” department:

        The next big CAGW push will be to eliminate domesticated ruminants for both meat-eating and other purposes. The ex dung-burning regions will look back on their cow-patty days with fondness when they try to cook on a solar stove at night or during the annual monsoon season.

      • Which one(s) at the table are thinking “Let them eat cake!”

    • Oh, and this is what they are grinning about while they shovel in the foie gras.

      http://www.telegraph.co.uk/finance/economics/12021394/COP-21-climate-deal-in-Paris-spells-end-of-the-fossil-era.html

      “A far-reaching deal on climate change in Paris over coming days promises to unleash a $30 trillion blitz of investment on new technology and renewable energy by 2040, creating vast riches for those in the vanguard and potentially lifting the global economy out of its slow-growth trap.”

      In this context, ‘vanguard’ means crony capitalist “green” energy boondoggles like Solyndra who hire Obama and other progressive potentates after his term ends.

    • As with all guest posts, please keep your comments relevant and civil.

    • Now that we’re into
      the festive season,
      time ter be jolly ‘n
      deck the halls,
      that image, blown up
      ‘d make a cute greeting
      card in the right spirit
      ter send ter yr friends,
      along with the charity lot,
      like Salvo’s Army, proceeds
      ter those in want, that
      we usually send.

      • So, justin, regardin’ those Xmas cards,
        if yer were mischievous, yer could print
        the two images side by side in a greeting
        card, kinda’ like that temperature and CO2
        increase non-correlation graph.

      • Bts, good idea! How about a picture book for busy elites or the suckers that believe what they say? Here’s page 2:

      • Page 4:

        COPD, from Wikipedia:

        “Poorly ventilated cooking fires, often fueled by coal or biomass fuels such as wood and animal dung, lead to indoor air pollution and are one of the most common causes of COPD in developing countries.[29] These fires are a method of cooking and heating for nearly 3 billion people with their health effects being greater among women due to more exposure.[1][29] They are used as the main source of energy in 80% of homes in India, China and sub-Saharan Africa.[30]”

        Why fix real problems when you can funnel public money to your.cronies? That is the real story, not TCR or ECS – interesting problems in climatology but red herrings wrt public policy. They serve as scientific cover for grand theft and the climate scientists are either collateral damage, true believers, dupes, or careerists. The silent careerists are the worst.

      • When in human history has a generation turned its back on the tradition of progress towards prosperity for all and said “Naw, put them on a treadmill with the hamsters.”

        I’m sure the little ones will get great comfort knowing their sacrifice of being cold and hungry is made for the betterment of ephemeral generations too distant to contemplate. Tough it out kid, take one for the cause.

      • justinwonder

        Your images give meaning to numbers, and the numbers of those developing COPD in the developing world tell a story, apparently the wrong sort of story that the CO2 and models numbers tell. The CO2 story as a priority of world leaders, leaves voiceless the 3 billion using biomass/dung as fuel to cook each and every meal.

        Far be it from me to point out that the pundits (I have a recent beef with Andy Revkin) are co-conspiritors in telling this story. These pundits prefer not to see the blinding acrid smoke filled eyes of these casualties of an energy future in developing countries devoid of coal based electric power.

        These women AND children die earlier than even slightly more economically advanced societies. These women, and certainly this is a women’s issue, are less able to perform the household duties as they advance to middle age. If you want to think of your young middle-aged daughters dying, acquiring tuberculosis or succumbing to influenza epidemic, or coughing their brain out still trying to stir the pot, not a lot of room for humanism in the elites view of our world, although of course, these people can dismissed these 3 billion as the casualties of the war on climate change.

        If you were a man from Mars stopping by and looking at the real disparity between the rhetoric of climate change and the injury to people of the developing world, would you frame the issue as…genocide?

      • jiw,

        “Why fix real problems when you can funnel public money to your.cronies? That is the real story, not TCR or ECS – interesting problems in climatology but red herrings wrt public policy. They serve as scientific cover for grand theft and the climate scientists are either collateral damage, true believers, dupes, or careerists. The silent careerists are the worst.”

        You nailed it. +100

      • justinwonder,

        +++.

        It’s even worse when you’re using dung for fuel. Even worse than that is when you run out of dung. That is a serious matter. I jest not!

        I’m sure Warmists will dismiss such real problems as trivial, preferring to sit in their air conditioned offices playing with their computers and each other.

        Cheers.

      • RiH008, it’s most of the main stream media mor-ns that are complicit. The NYT not only has Revkin, they also have Gillis, Egan and some new clown named Coral Davenport.

        I searched (almost back to Genesis) the NYT online site for articles on the subject and found 2 articles discussing providing Low Impact stoves to Africans. In 2010 Hillary Clinton announced a $50 million initiative to provide new environmentally friendly stoves to Africans. All the spin was around CO2 emissions reduction, nothing about COPD.

        The issues associated with providing affordable, plentiful, reliable energy to developing countries are manifold. Ruling out coal, as so many people want to do, is idiotic. Refusing to fund coal power plants in Africa (and India for that matter) is absurd, indefensible and short sighted.

      • Mark Silbert

        The wood burning stove issue is nothing more than an NGO feel-good accommodation to a situation that they have no idea about. Hilary Clinton is part of the NGO type of “solution” and not understanding that the burning of wood/dung/biomass creates a local climate of pollution that people inhale.

        NO type of wood burning stove that have been proposed, money spent developing and trying to get women to use, has ANY benefit:

        Chest. 2015 Nov 1;148(5):1184-92. doi: 10.1378/chest.15-0261.
        Lung Function in Rural Guatemalan Women Before and After a Chimney Stove Intervention to Reduce Wood Smoke Exposure: Results From the Randomized Exposure Study of Pollution Indoors and Respiratory Effects and Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter Study.
        Guarnieri M, Diaz E, Pope D, Eisen EA, Mann J, Smith KR, Smith-Sivertsen T, Bruce NG, Balmes JR.
        Abstract
        BACKGROUND:
        COPD is the third most frequent cause of death globally, with much of this burden attributable to household biomass smoke exposure in developing countries. As biomass smoke exposure is also associated with cardiovascular disease, lower respiratory infection, lung cancer, and cataracts, it presents an important target for public health intervention.

        METHODS:
        Lung function in Guatemalan women exposed to wood smoke from open fires was measured throughout the Randomized Exposure Study of Pollution Indoors and Respiratory Effects (RESPIRE) stove intervention trial and continued during the Chronic Respiratory Effects of Early Childhood Exposure to Respirable Particulate Matter (CRECER) cohort study. In RESPIRE, early stove households received a chimney woodstove at the beginning of the 18-month trial, and delayed stove households received a stove at trial completion. Personal exposure to wood smoke was assessed with exhaled breath carbon monoxide (CO) and personal CO tubes. Change in lung function between intervention groups and as a function of wood smoke exposure was assessed using random effects models.

        RESULTS:
        Of 306 women participating in both studies, acceptable spirometry was collected in 129 early stove and 136 delayed stove households (n = 265), with a mean follow-up of 5.6 years. Despite reduced wood smoke exposures in early stove households, there were no significant differences in any of the measured spirometric variables during the study period (FEV1, FVC, FEV1/FVC ratio, and annual change) after adjustment for confounding.

        CONCLUSIONS:
        In these young Guatemalan women, there was no association between lung function and early randomization to a chimney stove or personal wood smoke exposure. Future stove intervention trials should incorporate cleaner stoves, longer follow-up, or potentially susceptible groups to identify meaningful differences in lung function.

        Biomass burning is dirty. Stop trying to make a silk purse out of a sow’s ear.

        A colossal waste of money and human resources, fraudulent projections by NGO and AID people who would have seen their folly if they had bothered to come to see their creations literally blow up in their faces.

        Electric cooking is THE answer. A simple hot-plate in a bamboo hut with a thatched roof has a substantially reduced fire hazard and women have more options for cooking, clean water, and hand washing.

        Hilary Clinton is part of the problem for the developing world. Developing leaders would do well to ignore her except when she gives them money handouts which allow these leaders to jet to Monte Carlo just to pass the time.

      • Page 6:

        Olympic athlete was infected with MRSA after olympic test in Rio waters.

        Rio, ground zero of the CAWG movement and host of the ’92 “Earth Summit”, hasn’t found the time or money to build sewage treatment plants to rid the coastal waters of MRSA. I guess they have to go after the global warming ghost first, and those ghosts are hard to catch. Btw, I have travelled all over Brazil and I can tell you the network of rivers and creeks function as sewage pipes bringing the raw sewage of approximately 130,000,000 people to the big blue sewage treatment plant called the ocean. I suppose we really must fix CAWG first.

        http://hosted.ap.org/dynamic/stories/O/OLY_RIO_2016_FILTHY_WATER?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT&CTIME=2015-12-02-07-26-27

      • Justinwonder & cerescokid
        “Why fix real problems when you can funnel public money to your.cronies? That is the real story, not TCR or ECS – interesting problems in climatology but red herrings wrt public policy. They serve as scientific cover for grand theft and the climate scientists are either collateral damage, true believers, dupes, or careerists. The silent careerists are the worst.”

        Tell it like it is!

        “I’m sure the little ones will get great comfort knowing their sacrifice of being cold and hungry is made for the betterment of ephemeral generations too distant to contemplate. Tough it out kid, take one for the cause”…and Obama’s glory.

        When did Presidents consciously start pursuing glory as part of their job description? Repulisive in the extreme…but resonantes with his instincts and sensibiiities a la Paris and Islamic Extremism and National Priorities and lying his you know what off to shove Obamacare through and…with the right decoder ring it all resonates like dancing angels on the head of a pin. Now, how do we shove the whole mess over the edge into the abyss?

  5. Hansen’s seminal 1988 forecasts expected 0.91 deg of warming by now. Observed has been 0.40. Less than half. Forecast minus observed match your findings. See Scafetta for similar results.

    • As with all guest posts, please keep your comments relevant and civil.

      • Will no-one rid us of this troublesome priest.

      • Mosh

        I look forward to your substantive comments which are always worth while especially on a topic as fundamental as this. I hope you can make the time for something rather more reflective than these fly by’s .

        tonyb

      • Steven Mosher

        As with all guest posts, please keep your comments relevant and civil.

      • My topic is relevant, civil and on topic. Yours is just trolling at this point. You don’t run this blog.

        You have plenty of time to repeat the same statement over and over but haven’t taken the time to respond to my request on previous threads….

        Please identify a new version after adjustment of GISS or Hadcrut that shows a lower overall warming trend than the previous version.

        Skeptics have claimed that every new version shows a stronger warming trend. I found this unlikely but so far haven’t been able to prove them wrong. I have asked you repeatedly to help provide a contrary case for me but you never respond to the actual question.

        I’m still waiting in a civil manner.

      • Since Nick was too humble to do so, I’ll post a link to his revisit of Hansen 1988.

        Yep.

        For the MSU era, all observations trend lower than Scenario C:

        And yet some, including the old man himself, scare the public with ‘worse than expected’

        And some of the less discriminating believe.

        Amazing, no?

      • RE: Nick Stokes | December 2, 2015 at 2:43 pm |

        I’ll give Hansen 1988 an A+. Not for accuracy, but for scenario.

        Hansen Scenario A used a 1.5% a year growth in emissions. Actual from 1988-2013 was 1.8%. So I would argue that Scenario A+ emerged.

        Hansen apologists fudge on the Scenario and they fudge on the verification. The combination makes the forecast verification look a whole lot better than it really is, though still way too warm. He said Scenario A was unlikely because he didn’t think we could pump that much CO2. But we did and then some. Claiming than “between B and C” verified is .. to try to be nice… disingenuous.

        Bottom line… emissions have been higher than Hansen’s Scenario A. Global temp assessment is most robust with a consensus both near-sfc and satellite data. Using the appropriate benchmarks…Scenario A and WTI… Hansen over-forecast by more than factor of 2.

        Just to be clear… I’m not discounting computer models or Hansen 1988. Hansen was right. Temps have gone up. And by a significant amount. Skeptics miss that point. If CO2 was not a factor, then there was a 50-50 chance of falling temps. .

    • Neither figure quoted is true. Such statements are worthless without specifics.

      • Forecast: Hansen 1988 scenario A
        Observed: WTI to Oct 2015

        Pretty easy to verify and accurate to a couple of hundredths of a degree. http://postimg.org/image/5fkbyaa8x/

      • Since Nick was too humble to do so, I’ll post a link to his revisit of Hansen 1988.

      • Misplaced, but still,
        all observations trend lower than Scenario C:

      • Now, all trends should trend lower than scenario C, because Hansen had forcing too high.

        Even more reason for him to admit he was wrong and that warming has been less than expected!

      • BTW, Nick, the scenario data is here:
        http://www.realclimate.org/data/scen_ABC_temp.data
        so you can include it in your on line tool.

      • Roscoe Shaw,
        “Forecast: Hansen 1988 scenario A
        Observed: WTI to Oct 2015”

        OK. Without that specification the numbers are worthless. And with it, we can see just how wrong they are. Using the figures linked by TE, diffreence in projection 2015-1988 is
        A: 0.815, B:0.635, C:0.400
        None are at 0.91. But when scenarios are specified, you then have to ask what scenario was closest to the GHG forcings that eventuated. And the answer is, between B and C.

        On the data side, Hansen was not projecting the WTI index, which is half troposphere. He was projecting surface air temperatures. Not even the modern GISS, HADCRUT etc, which are mainly SST. But anyway, the difference between average 2015 so far and 1988 is 0.43 for GISS and 0.51 for HADCRUT. Both between B and C, though within that range a little on the low side. Nothing like half.

      • Scenario A is what happened… “business as usual”. CO2 and other levels verified closer to Scenario B because the earth is better at mitigating than Hansen assumed.

        But lets be clear… Scenario A is what happened. Emission have not been cut or slowed.

      • “the earth is better at mitigating than Hansen assumed”
        Hansen didn’t assume. That’s why he analysed three scenarios, not one. He has a program which calculates the response of the atmosphere to forcing. He doesn’t predict forcing – that depends on what people decide to do, and he doesn’t claim to know that. A specific GHG trajectory was the definition of each scenario (not words like “business as usual”), and what happened was between B and C.

      • If you want to argue about words, here is what he said in his 1988 paper, p 9345:

      • Nick Stokes here does a good job of pointing to another uncertainty in predicting the future climate and that is the scenario uncertainty. I think that uncertainty gets lost in the discussions of other uncertainties like model output that should at some point have some physical basis and predictability within limits. Scenario uncertainty not so much.

  6. Re-post. I don’t know why it wasn’t worthy first time. No swear words.

    “The mean carbon cycle behaviour of CMIP5 ESMs and EMICs may be quite unrealistic.”

    No shit.

    Keep watching the δ14C. It is now returned to pre bomb-spike levels.

    This is the critical part of the ‘atmospheric radio-carbon experiment’. If the continuing anthropogenic contribution to the the atmospheric CO2 content is correct, per the Bern model, then it will show an annual decrease of 14C of about 3% per year.

    As far as I can tell, Levine et al appear to be careful, decent, honest, and excellent, scientists. But I am not sure that I agree with their interpretations of their own data.

    Keep watching for the latest δ14Cdata from Jungfraujoch and Schauinsland.

  7. So, a sluggish upward sea level trend from the 1700s, continuing sluggish; a likely temp boost from the 1800s (hard to say, esp since min/max cannot = temp); that steepish temp rise (maybe) after 1910…

    And CO2 is known to behave a certain way in glass receptacles. Putting all that together, and in view of that pic published above by GaryM, I’d say my idea of completely obliterating the climatariat is still looking good.

    While at it one could also obliterate the EU and sell Belgium to the Chinese Congo.

    • Mosomoso,

      In case you missed it, Daniel E. Hofford is a new recruit for your climatariat destruction force.

      When do we get started?

      • Well, Mark, we’re a bit like the other side, strategy-wise. We turn hard cash into soft outcomes, if you know what I mean.

        You guys send me money till I say you’ve given enough. And Dear Leader here will invest it in qangos with names like “Foundation for as Better Future for Our Asthmatic Polar Bear Folks’ Kids”.

        Don’t sweat the details for now. Just send money. Bitcoin and PayPal accepted, but watch those Western Union charges.

    • The Chinese would never take Belgium. They’re communists, not stupid.

  8. It can be easily shown from the Carbon isotope trend in the atmosphere (often incorrectly cited as evidence that human Carbon is at fault) that a substantial increase in photosynthesis is necessary to keep the atmosphere from declining in 13C at a far faster rate than is observed. The reality is that all of the inputs to the atmosphere save the high 13C residual from photosynthesis (whether on land or from plankton at water interfaces) at about +18 PDB and the small air to ocean residual of +2 are strongly depleted in 13C. But for the photosynthetic sink, the atmosphere would be losing 13C much, much faster than it is.

  9. I can use the historical record over the last 60 years to show 1 C per 100 ppm which works out at 2.4 C / 1000 GtC, so the models track that quite well. This graph is scaled to 1 C per 100 ppm.
    http://www.woodfortrees.org/plot/gistemp/mean:12/from:1950/plot/esrl-co2/scale:0.01/offset:-3.25

    • JimD

      We can use the historical record over 4000 years which might give an even better context

      How do the models track with that? Mind you, according to Mosh there are no other stations showing cooling so CET is obviously an outlier. Is it? I dunno.

      tonyb

      • Whoops! 400 not 4000 years.

        tonyb

      • 400 not 4000 Oops, no matter, it has been about the same for t0,000 years.

        up and down and up and down and …….now up and down and up again now in the same bounds. They do not understand or even suspect what causes this natural cycle.

        Their models produce only hockey sticks, nothing with the up and down cycles.

        How sensitive is global temperature to cumulative CO2 emissions?

        They don’t know how sensitive global temperature is to what causes the natural cycle. it will keep this warm period warm about as long as the Roman and Medieval warm periods where warm and it will snow during this warm period and rebuild the ice that will take us into another cold period like the little ice age. The ten thousand year data does show that this always happens. If cumulative CO2 adds energy, it will melt sea ice more and turn on more snowfall. The end of this normal warm period will be a normal cold period.
        The tilt of the earth made a huge change over the past ten thousand years, moving energy out of the northern hemisphere and into the southern hemisphere and it changed the temperature in both hemispheres by nothing that shows up in the data.
        http://popesclimatetheory.com/page85.html

        Temperature is regulated. The thermostats are set at the temperature that Polar Sea Ice Melts. The cooling is powerful and it is the snowfall that is turned on when the sea ice thaws. Warm times are the times during which ice on land is replenished. These warm times are natural and necessary.

        Consensus theory makes earth cold, freezes the source for snowfall and then adds the ice to earth as a result, as a feedback. How do they get the moisture from frozen oceans?

    • The part I don’t get is that we have had 1 C from about 500 GtC accumulated emissions, so from that observation alone we have near 2 C / TtC, not anything near 1.15 C / TtC. Also in terms of CO2 amount, we have had 1 C from about half a doubling, again near 2 C per doubling, and that is just transient which is below ECS. The stated numbers in the post don’t agree with even the first observations you might try.

      • Jim D: The part I don’t get is that we have had 1 C from about 500 GtC accumulated emissions, so from that observation alone we have near 2 C / TtC, not anything near 1.15 C / TtC.

        Your estimate of sensitivity is calculated differently from Nic’s estimate of sensitivity, and you believe your estimate. Your estimate attributes all of temp increase to the CO2 increase, ignoring any possible confounding. Nic’s estimate assumes some of the temp increase has been due to mechanisms independent of CO2. It is not that hard to reconcile the differences.

      • Nic seems to have 0.9 C for the first half of the doubling and (1.15-0.9=)0.25 C for the second half. There may be some hidden assumptions in having such a drastic change to drop it below a log-rate doubling that requires these two to be equal. If you know what that assumption is, I would like to hear it.

      • I should have said Nic Lewis has 0.9 and 0.45 for the first and second halves of the doubling, since his model has a TCR of 1.35 C per doubling. This is still a large drop-off from the log rate.

    • Jim D
      “I should have said Nic Lewis has 0.9 and 0.45 for the first and second halves of the doubling, since his model has a TCR of 1.35 C per doubling.”

      Taking RCP6.0 as an example, the ratio of the rise in GMST to the rise in forcing in my model is almost the same over 1870 to the 2000s (during which cumulative CO2 emissions were ~450 GtC) as it is from the 2000s to the 2050s (during which cumulative CO2 emissions are ~520) GtC – between 1.35 C and 1.4 C for each, when multiplied by the forcing for a doubling of CO2 concentration so as to get an approximate TCR (which, as I stated, is slightly over 1.35 C). The GMST change is ~0.55 K in the second period compared with ~0.75 K in the first – your figures are not quite right.

      Although there is slightly more CO2 emitted in the second period, the CO2 forcing change is only 80-85% as large, primarily due to the logarithmic relationship between CO2 forcing and concentration. And the increase in non-CO2 forcing, which equates to 35-40% of CO2 forcing in the first period, is only half as much in the second period. Hence the total forcing change in the second period is substantially smaller than in the first period, which accounts for the smaller GMST rise.

      So there is no mystery here, and no involvement of any factors other than forcing and, to a minor extent, changes in heat uptake.

  10. Nic,
    The SPM version seems to show past values close to observed, and continuing to 1000 GtC. Yours shows a sensitivity for the next 500 GtC considerably lower than past observed, in your plot. Do you have modelled values for the past? Do you see a reason for the reduction?

    • Nick,
      Thanks for your comment. The solid black line in my figure shows GMST as simulated by my model, not observed values. The only observed value is shown by the horizontal pink line.
      There is no difference between past and future sensitivity of temperature to forcing in my model. If the airborne fraction of cumulative CO2 emissions stays constant, forcing will increase more slowly with cumulative emissions in the future than in the past, because of the logarithmic relationship between atmospheric CO2 concentration and CO2 forcing. GMST increase in my model is closely related to total forcing, so it GMST also increases more slowly.
      It is the behaviour of CMIP5 models, with almost the same sensitivity of GMST to increases in cumulative emissions in the future as in the past, that needs explaining. I think there are three mains reasons for this counterintuitive behaviour:
      1. Past warming in CMIP5 models has been reduced by unrealistically large negative aerosol forcing – on average even stronger than per RCP estimates, which in turn exceed the AR5 best estimate. Aerosol emissions and hence forcing declines in future under all RCP scenarios, so part of this past excessive aerosol cooling in CMIP5 models turns into excessive future warming (although the effect in future is fairly small relative to CO2 forcing). In my model, RCP aerosol forcing is scaled to match the AR5 best estimate in 2011, increasing total RCP forcing in the past and reducing it slightly in the future.
      2. CMIP5 ESMs have a much greater difference between ECS and TCR (~3.4 – 1.9 = 1.5 C) than does my simple ESM (1.7 – ~1.35 = 0.35 C). That means there is far more “warming in the pipeline” arising in the historical period that emerges over the rest of this century. To an extent, that is reflected in greater warming to date of the subsurface ocean in CMIP5 models than is observed (which my model is constrained to match). See Figure 9.17(b) of AR5 (corrected version). Additionally, in most CMIP5 models effective sensitivity rises with time, so their warming in the pipeline exceeds the level one would expect based on heat uptake.
      3. Both ocean and land carbon sink strength are adversely affected by temperature increases, land carbon uptake being ~7 times more sensitive than ocean uptake in CMIP5 ESMs. Observational evidence, which my simple ESM reflects, points to the actual sensitivity of land carbon uptake to GMST being only about half the mean CMIP5 ESM level. Interestingly, the only CMIP5 ESMs with a land scheme having coupled carbon and nitrogen cycles have an even lower sensitivity of land carbon uptake to GMST (Arora et al 2013) than per the observational estimate that my model uses. The greater future GMST rises with cumulative emissions projected by CMIP5 ESMs, allied to their much greater sensitivity of land carbon uptake to temperature, results in considerably lower carbon sequestration in CMIP5 ESMs than in my model, and hence in a higher airborne CO2 fraction, higher CO2 forcing and greater GMST increase in CMIP5 models.

      • If the airborne fraction of cumulative CO2 emissions stays constant, forcing will increase more slowly with cumulative emissions in the future than in the past, because of the logarithmic relationship between atmospheric CO2 concentration and CO2 forcing. GMST increase in my model is closely related to total forcing, so it GMST also increases more slowly.

        If being the operative word here. Most analyses suggest that the airborn fraction will increase with increasing emissions. Since you now seem to think that you have expertise in the carbon cycle, it would be interesting to know if you still think that only a small fraction of our emissions will remain in the atmosphere for hundreds of years and, if so, what you mean by a small fraction.

        As you probably also realise, your model assumes that feedbacks are precisely linear. There are many reasons to think that this assumption is simplistic and probably wrong. Even if the feedbacks themselves are not strictly non-linear, it seems that the spatial dependence could lead to an effective non-linearity in that different regions warm differently, so that we – in a globally averaged sense – initially warm more slowly than we do later (in a doubling of CO2 analysis).

        I’m also not sure that this is consistent with your large TCR/ECS ratio

        To an extent, that is reflected in greater warming to date of the subsurface ocean in CMIP5 models than is observed (which my model is constrained to match).

        If we have a large TCR/ECS ratio (i.e., the TCR is close to the ECS) then I think that would imply that the subsurface ocean should warm slowly so that we approach equilibrium rapidly, and then very slowly warm the deeper ocean. If the transfer of energy to the deeper ocean is faster, then that suggest that we can sustain a larger planetary energy imbalance – than if it were slower – and, hence, the difference between the TCR and ECS would be larger.

      • Nic,
        Are you suggesting by this that in your model the airborne fraction remains constant?

        If the airborne fraction of cumulative CO2 emissions stays constant

        As I understand it (and Nick Stokes is more expert at this than) me, this is almost not correct. For example, in Chapter 6 of AR5 WGI, it says

        The capacity of the ocean to take up additional CO2 for a given alkalinity
        decreases at higher temperature (4.23% per degree warming;
        Takahashi et al., 1993) and at elevated CO2 concentrations (about 15%
        per 100 ppm, computed from the so called Revelle factor; Revelle and
        Suess, 1957).

      • Most analyses suggest that the airborn fraction will increase with increasing emissions.

        Looks like those analyses may be incorrect:

      • Nice illustration of the pause foolin’ people.

      • ATTP,
        In my model, the airborne fraction – which is a value calculated from model output, not a specified input – remains approximately constant in the future, as it has in the past. But that is not because the model ignores the temperature sensitivity of the ocean carbon system – it has the same sensitivity of the ocean carbon sink to temperature as the average CMIP5 ESM. As temperature rises less in my model, the reduction in ocean carbon uptake is however lower in my model’s projections than those of CMIP5 models. But the big difference of my model’s carbon-cycle behaviour with CMIP5 models is for the land carbon sink.

      • Nic,
        Okay, so your reduced sensitivity (which may be too low) leads to a reduced influence on ocean uptake, and you make assumptions about the land carbon cycle that lead overall to an airborne fraction that remains roughly constant? If wishes were horses…..

      • Nic,
        Okay, so your reduced sensitivity (which may be too low) leads to a reduced influence on ocean uptake, and you make assumptions about the land carbon cycle that lead overall to an airborne fraction that remains roughly constant? If wishes were horses…..

        ATTP, as the chart above indicates, the airborne fraction of CO2 has actually decreased as emissions and temperature have increased.

        Why would you believe something which is so distinctly contradicted by observation? What might that tell you about your beliefs?

        CO2 is taken up by living creatures. The recent work on increased phytoplantkton should be an indicator.

        CO2 is also taken up by cold water, but not by ice. Warming average ocean temperatures don’t mean that cold water formation stops. In fact, were the total ocean 0.x degrees warmer, it would increase sequestration of CO2, because a pool of near freezing water at the surface ( the formation of which continues at the poles ) would descend more readily.

        Predictions that CO2 uptake would slow are not just unfounded, they’re contradicted.

      • TE,
        Not everyone agrees, but you absolute certainty never ceases to amaze.

      • TE,

        You haven’t included land use fluxes so your results are biased towards a negative trend. Published studies have generally found a multi-decadal increasing airborne fraction trend though without passing significance, partly due to large uncertainty in emissions data.

      • TE,
        Not everyone agrees, but you absolute certainty never ceases to amaze.

        Plots of the observed data are produced by Sato and Hansen.

        Airborne fraction of emitted CO2 appears to have decreased from around 60% in 1960 to less than 50%.

        Dismissing this is akin to those who would claim there is no warming.

        Good luck in your struggle against this reality.

      • TE,
        Did you actually look at the paper to which I linked?

      • TE,
        I’ve also just looked at the paper where that figure comes from. Paulskio is quite correct. The airborne fraction in that figure is based on the observed increased in atmospheric CO2 and fossil fuels emissions only. In other words, it doesn’t take into account all anthropogenic emissions.

      • You haven’t included land use fluxes so your results are biased towards a negative trend.

        The data include all fluxes since it represents the annual increase in accumulation as a fraction of emissions.

      • TE,

        Perhaps you’re misunderstanding? Land use change is a source of human co2 emissions which is not included in that emissions data. Estimates are that land use change emissions have been pretty static since 1960 so relative contribution becomes smaller over time. That means airborne fraction is increasingly biased high as you go back in time when using only fossil fuel emissions.

      • Nic Lewis, thank you for the essay.

      • TE,
        As paulskio points out, it doesn’t include all the emissions.

      • and Then There’s Physics: but you absolute certainty never ceases to amaze.

        Where did TE exhibit absolute certainty? He wrote a proposition consistent with the evidence he presented.

      • matthew,

        Good luck in your struggle against this reality.

        A reality that – it turns out – does not include all the relevant information.

      • and Then There’s Physics: Not everyone agrees,

        thank you for the link. Interestingly, the two papers agree on a declining airborn fraction since 2000, and both show a gradual rise since 1960 followed by a decline.
        from the source: For AF, our best trend estimate (Fig. 2 and Table 1) is RGR (AF) = 0.24 ± 0.20 % year −1 (±1σ , P = 0.89) about a mean h AF i of 0.44 over 1959.0–2013.0, where ±1σ denotes a 1-standard-deviation confidence interval, and the significance (P ) is the probability of positive trend.

        Hence, the estimated trend is not different from 0.

        The proposition of constant airborn fraction is reasonable. If not constant, would you recommend a quadratic relationship?

      • and Then There’s Physics: matthew,

        Good luck in your struggle against this reality.

        What’s that about?

      • TE,
        The airborne fraction in that figure is based on the observed increased in atmospheric CO2 and fossil fuels emissions only. In other words, it doesn’t take into account all anthropogenic emissions.

        Such as, what, exactly?

      • Oh, I see, he’s trying to use an estimate for deforestation that has decreased somewhat over the decades ( figure C1 ). I’m guessing there’s a lot of fuzz in that estimate.

        Interesting, though, that Oceanic and Land uptake indicate continued rates of increase.

      • Matthew,
        The “reality” quote was from TE to me, not me to you

        Hence, the estimated trend is not different from 0.

        Yes, I think this is indeed a fair assessment of the current position. Hence TE’s claim that it is decreasing seems incorrect.

        <blockquote
        The proposition of constant airborn fraction is reasonable. If not constant, would you recommend a quadratic relationship?

        I don’t have a specific recommendation. However, our understanding of the ocean uptake (Henry’s law, the Revelle factor) suggests that the ocean uptake should decrease with increasing T and increasing CO2. Land uptake is a bit trickier, but the general view is that it will also weaken. I do not think Nic’s model disagrees with this, but I think he has chosen carbon cycle feedbacks that are on the low side of the range, and hence the airborne fraction does not change much as we warm because the selected TCR is also on the low side of the range.

        TE,
        It does not include anthropogenic land use emissions, as paulskio has pointed out a number of times already.

      • Hansen:
        “A decrease in land use emissions during the past decade (Harris et al 2012) could contribute to the decreasing airborne fraction in figure 3, although Malhi (2010) presents evidence that tropical forest deforestation and regrowth are approximately in balance, within uncertainties.”

      • However, our understanding of the ocean uptake (Henry’s law, the Revelle factor) suggests that the ocean uptake should decrease with increasing T and increasing CO2.

        Not nearly so simple as that.

        CO2 seems to be entering and exiting the oceans due to factors other than temperature:

      • Not nearly so simple as that.

        Noone ever said it was simple.

      • and Then There’s Physics: Most analyses suggest that the airborn fraction will increase with increasing emissions.

        That turns out to be unsupported, and you subsequently agreed that the trend is not different from 0.

      • and Then There’s Physics: Noone ever said it was simple.

        You wrote a simple proposition. However, our understanding of the ocean uptake (Henry’s law, the Revelle factor) suggests that the ocean uptake should decrease with increasing T and increasing CO2.

        Are you backing off from what you wrote?

      • TE,

        If you’re focusing just on the most recent decade, as JCH indicated, that pattern looks rather pausey. Will it be surgey? Time will tell.

      • The whole thing with the anomalously strong winds in the equatorial and Northern Pacific after 2005 is a wildcard. In the past here on a CE I nicknamed them the KImikamikaze Winds, for the poetic kooler. Will they come back? If so, when? But as soon as they calm, the warming will fill right back in. They’re not going to change anything other than the potentially completely fooled themselves level, which is pretty high… relevant and at least as civil as Feynman.

      • This thread started with a question about airborne fraction of CO2 and moved into disagreement over land use contributions. I didn’t see a clear resolution on that point but I also did not find TE’s point refuted.

        When I’ve looked for deforestation trends I can’t find much decline in the global trends (since Indonesia’s deforestation has increased markedly in recent years as Brazil’s declined).

        According to WRI:

        More than 62 percent of tropical tree cover loss in 2014 occurred in countries outside of Brazil and Indonesia, compared to 47 percent back in 2001.

        http://www.wri.org/blog/2015/09/satellites-uncover-5-surprising-hotspots-tree-cover-loss

      • Nic,

        1. Past warming in CMIP5 models has been reduced by unrealistically large negative aerosol forcing – on average even stronger than per RCP estimates, which in turn exceed the AR5 best estimate.

        How have you determined this? If it’s based on the subset of CMIP5 models featured in Zelinka et al. 2014 or AR5 Chapter 7 those are biased samples. All models featured by Zelinka et al. include indirect (aerosol-cloud) aerosol effects. Most of the remaining CMIP5 models do not include indirect effects so have substantially less negative total aerosol forcing.

        The overall median and mean is probably very close to the AR5 best estimate, maybe slightly above, maybe slightly below. The strongest mode would be around -0.4W/m2, with a sort of sloped distribution.

        If you’re referring to the subset of CMIP5 models which were used to produce the cumulative emissions sensitivity chart, assuming those are the ones listed in Table 6.11, half of these do not include indirect effects so the average is probably about the same to slightly less negative than the AR5 best estimate.

      • Opulso,

        I’m not clear what you think TE’s point was?

        TE’s graph describing time-evolving airborne fraction (CO2 ppm growth/emissions growth) didn’t include land use change CO2 emissions in the emissions growth term. Lack of long-term trend in land use emissions is precisely why the airborne fraction trend will be biased negative if you don’t include land use emissions.

      • I’m not clear what you think TE’s point was?

        TE’s graph describing time-evolving airborne fraction (CO2 ppm growth/emissions growth) didn’t include land use change CO2 emissions in the emissions growth term. Lack of long-term trend in land use emissions is precisely why the airborne fraction trend will be biased negative if you don’t include land use emissions.

        I am no expert on land use based CO2 budgets.
        Of course, neither are you nor Kenny.

        I did cite the Hansen data which excludes land use because, as Hansen writes, there is some indication that land use is net zero.

        I will say that fuel based CO2 emissions are likely known confidently because the sales of fuel leaves a pretty good record.

        Land use is probably very poorly known because there are few measurements and lots of small scale changes spread over a nation.

        It does point out confirmation bias Kenny likes the end of the world CO2 uptake is slowing down data.

        I focused on the existing Hansen publication and was slow to read his citation.

        Ultimately, examining the decelerating forcing record, which avoids the unknowns of the budget, makes uptake a moot point.

      • Interestingly, matthewmarler’s comments bypassed AT’s main point:

        I think he has chosen carbon cycle feedbacks that are on the low side of the range, and hence the airborne fraction does not change much as we warm because the selected TCR is also on the low side of the range.

        So far, Nic failed to pick on this small detail too.

        After all, a main point becomes a very tiny nit when one only repeats it once every few comments.

        INTEGRITY ™ – Lower Is Better

      • paulskio,
        I’d quite like to understand Nic’s claim about the aerosol assumptions in models better too. I would also be keen to have Nic explain on what he’s basing his claim that the aerosol forcing in the models is too negative (or that the mean is too negative) and – if it is – how big an effect it is.

      • TE,

        I am no expert on land use based CO2 budgets.
        Of course, neither are you nor Kenny.

        We’re not experts on fossil fuel CO2 budgets, airborne fractions or the carbon cycle either. Should we pack up and go home? :)

        as Hansen writes, there is some indication that land use is net zero.

        The paper Hansen references (Malhi 2010) is about changes in sources and sinks of carbon in tropical forest regions from 1990-2005. Note the sources seem to be exclusively anthropogenic – land use CO2 emissions – but the sinks are natural – that is, sinks have been taking in increasing amount of CO2 as emissions have been growing. That the net result is not significantly different from zero does not indicate zero land use anthropogenic CO2 emissions, but rather that the natural sinks in this region have also been increasing their uptake as total anthropogenic emissions and concentrations have increased.

        I will say that fuel based CO2 emissions are likely known confidently because the sales of fuel leaves a pretty good record.

        Land use is probably very poorly known because there are few measurements and lots of small scale changes spread over a nation.

        Sure, but it is known enough for us to recognise that the fraction of total emissions from land use change has decreased considerably, and therefore excluding land use emissions from an airborne fraction calculation will cause a bias.

      • willard: Interestingly, matthewmarler’s comments bypassed AT’s main point:

        One of Nic’s propositions was that the airborn fraction of CO2 was constant. aTTP countered that there was contradictory evidence, and provided a link. At the link, the paper supported Nic’s proposition that the airborn fraction was constant. When I pointed that out, aTTP agreed and countered that he had only meant to counter TE’s proposition, posted after aTTP had countered Nic’s proposition, namely that the airborn fraction was declining.

        In short, Nic’s proposition of a constant airborn fraction is supported by the evidence.

        aTTP’s claim that he was merely countering TE’s claim that the airborn fraction was declining is belied by the actual order of the postings. TE was contradicting aTTP’s claim that “most analyses” showed the airborn fraction rising.

        Amidst the mush, it is useful sometimes to clarify which propositions are and which propositions are not supported by the evidence. Nic Lewis’ assumption of a constant airborn fraction is concordant with the evidence supplied by aTTP and TE.

      • So, this post is now aged, but for those still looking…

        CO2 emissions and CO2 from land use estimates are available from RCP through 2005. Also from CDIAC through 2011.

        a = e – u
        where a = accumulation, e = emissions, u = uptake

        e can assume land use is zero, or includes the land use estimates ( which seem to have precisely constant values for most continents! Accurate? Precise? )

        Most depictions of this are relative to emissions, which doesn’t make sense to me. Aside from some marginal isotope differences, uptake processes don’t ‘know’ or ‘care’ whether the CO2 is from this year or a century past.

        Here is the result. CO2 uptake increases with increasing CO2 concentration:

        http://www.pik-potsdam.de/~mmalte/rcps/index.htm#Download
        http://cdiac.ornl.gov/trends/landuse/houghton/1850-2005.txt
        http://cdiac.ornl.gov/ftp/ndp030/global.1751_2011.ems
        ftp://aftp.cmdl.noaa.gov/products/trends/co2/co2_annmean_mlo.txt

  11. Not even Scientific American can get this right. Why do they imply that doubling of CO2 is 800 ppm from a base of 400 ppm. No wonder there is so much confusion in the minds of the public and policy makers.

    http://www.scientificamerican.com/article/the-most-important-number-in-climate-change/

    “Among all the numbers commonly bandied about global warming, the most important one in climate change is not 400 (parts-per-million CO2 in the atmosphere), two degrees Celsius (average warming of global temperatures), one trillion tons (of carbon budget), or even $100 billion (in climate adaptation funding per year). It’s not even a single number, it’s a range: 1.5 degree C to 4.5 degree C, according to the most recent effort of the United Nations Intergovernmental Panel on Climate Change, the Nobel Peace Prize-winning IPCC.

    That’s the expected global warming over centuries from a doubling of atmospheric CO2 based on the output of around 40 planetary-scale simulations of the ocean and atmosphere known as global climate models.”

    At least climate.gov got the facts right – 275 ppm.
    https://www.climate.gov/news-features/climate-qa/how-much-will-earth-warm-if-carbon-dioxide-doubles-pre-industrial-levels

  12. Pingback: Dos preguntas para @carlos__alsina : 1 ¿Qué hechos en concreto negamos los “negacionistas”? 2 ¿Que tendría que observar para contemplar estar equivocado? | PlazaMoyua.com

  13. The SPM.10 graph 1%/yr thin black line shows a 2 °C temperature rise corresponds to 1200 GtC, which is 1.67 °C/1000 GtC. I believe Nic incorrectly wrote “the transient climate response to cumulative carbon emissions (TCRE) – is 2.4°C/GtC at a 2°C rise from 1870.” That should be 1.67 °C/1000 GtC. Our annual emissions of CO2 are about 10 GtC/year.

    AR5 said “the TCRE is likely between 0.8°C to 2.5°C per 1000 PgC”. Note that 1 PgC = 1 GtC. Nic then in correctly wrote “The 2.4°C/GtC CMIP5 mean is only just below the top of that range.” No, the CMIP5 mean TCRE of 1.67 °C/1000 GtC is in the middle of the range 0.8°C to 2.5°C/1000 GtC.

    NIc wrote, “It estimated a 5–95% range for TCRE of 0.7–2.0°C/GtC, implying that the 2.4°C/GtC CMIP5 mean TCRE is too high”. That should be “It estimated a 5–95% range for TCRE of 0.7–2.0°C/1000 GtC, implying that the 1.67°C/1000 GtC CMIP5 mean TCRE is too high”

    Note that the units given at the top of figure SPM.10 are incorrect. It shows GtCO2. The units are correctly given at the bottom of the figure as GtC.
    [1 tC = 3.664 tCO2]

    • Ken,
      Thanks for your comment. I agree that the “pure” TCRE of CMIP5 ESMs is lower than 2.4°C/GtC, hence my statement about the 2.4°C/GtC being above the top of the attribution study 0.7–2.0°C/GtC range even allowing for the element of warming from non-CO2 forcing. However, most users of Figure SPM.10 focus on the relationship of GMST increase to cumulative emissions on RCP scenarios, not on a TCRE based on 1% per annum increases in CO2 concentrations. AR5 doesn’t specify what basis is to be used for calculating TCRE, but it does say (12.5.4.2): “The ratio of global temperature change to total cumu¬lative anthropogenic CO2 emissions (TCRE) is relatively constant over time and independent of the scenario”.

      If one adjusts the CMIP5 RCP6.0 projection for the decade in which it just passes a 2°C increase in GMST, by removing warming corresponding to the non-CO2 element of RCP6.0 total forcing, the TCRE reduces to just over 2.0°C/GtC. I don’t think that the CMIP5 mean TCRE of 1.67 °C/1000 GtC on 1% per annum increases in CO2 concentration is representative of the behaviour of CMIP5 ESMs in the RCP scenario simulations (which are not an identical set of models).

      It might have been better if I had said that, allowing for the element of warming from non-CO2 forcing, the CMIP5 TCRE was around the top of the 0.7–2.0°C/GtC range. However, the comparison of the RCP6.0 TCRE of 2.4°C/GtC for CMIP5 ESMs with a TCRE of 1.15°C/GtC for my model, both at the point where GMST has risen 2°C, is fair – both are almost equally impure measures.

      The units given at the top of Figure SPM.10 are in fact correct. The values are the equivalent, in units of GtCO2, of the values in GtC given at the bottom of that figure.

  14. The peak for 2.6 occurs (using the RCP3.0 data which I have) in 2044 with 4.0 GT/Y of emissions.

    Currently about 6.0 GT of emissions are being absorbed and the number is rising, fast. Just assuming that 6.1 GT/Y is absorbed in the future the “peak” year is 2034 – a decade earlier.

    The 2034 value is 450. Since the RCP predicts a linear drop (2.3 PPM/Y + 0 PPM/Y)*19 = 43.7 or a level of 443.7.

    But realistically the absorption at 443.7 is about 7.7 GT/Y or the value for 2027.

    Bottom line – CO2 atmospheric level is going to top out on 2030 at around 430 PPM. and decline thereafter.

    The 2100 CO2 level won’t be 426 but something below 400. And we know 400 is safe – we have tested it.

    We can accomplish the worst case of the low emissions scenarios by having an emissions hiatus. All we have to do is not make things a lot “worse”.

    I still don’t understand what people have against making plants grow.

    I would prefer we let emissions go their merry way and every 10 years assess if things are better or worse.

    When global warmers can prove net harm, beyond hurt feelings that we didn’t listen to them we can reassess and change course.

    We need the CO2 to grow more food. The benefit of more CO2 has a proven track record and is easy to demonstrate, greenhouses do it all the time. To this point the CO2 harm is a fairy tale and we shouldn’t be making public policy based on fairy tales.

    Global warmers should have to demonstrate harm before we listen to them.

  15. As I am out for the day carrying out research I will leave everyone with Callendar’s co2/temperature rise graphic on page 231

    http://www.rmets.org/sites/default/files/qjcallender38.pdf

    Like Arrenhuis, Callendar was very positive about the effects of co2.

    Incidentally, it is a shame we use that start dates we do, as we miss out on the notable warm hump that immediately precedes the Giss temperature calculations, or the much cooler period from 1810 or so illustrated in CET and BEST to 1750. What would sensitivity calculations look like if graphed against other warmer and cooler start scenarios?

    tonyb

  16. As far as I know, no attempt to verify the warming effects of CO2 by experiment has ever succeeded. Therefore the proposition that global temperature (whatever that may be), are caused by CO2 emissions, is doubtful in the extreme.

    It is trivially obvious that oxidising carbon to create CO2 creates heat. An increase in heat is often noted by an increase in temperature. There are other reasons for local or widespread increases which also involve a concomitant rise in CO2. There are many other reasons for apparent warming which are related merely to the removal of a temporary cooling influence, such as a decrease in cloud cover, a reduction in other albedo, and so on.

    As the Earth has progressively cooled since its creation, regardless of atmospheric composition, any assertion that increased CO2 levels result in increased temperatures, particularly in the absence of experimental confirmation, is just complete nonsense.

    Correlation does not necessarily imply causation. The models are failing – poorly designed, and based on voodoo Warmist physics. Total rubbish.

    Cheers.

    • Mike you keep saying this but is it fair?
      By experiment do you mean in a lab or in a planet, The latter would be a bit too hard to do. Surely the former has been done?
      If such experiments have been done showing absolutely no warming from CO2 [which in itself would still be a success for the experiment], then your assertion would be correct. But these experiments would also have convinced all scientists of this fact. Since they are obviously not convinced either the experiments have not been done or have shown some evidence of warming, surely?

      The fact that different substances have different absorption and emission frequencies is not disputed even if the consequences are.
      While the earth has generally progressively cooled since it’s creation that has little to do with the concept that different atmospheric compositions can exert some effect on surface temperatures.
      This would be intellectually true even in the absence of experimental confirmation.
      Correlation does not imply causation but it is still nice to have correlation when attempting to determine causation.

    • angech2014,

      You wrote –

      “Mike you keep saying this but is it fair?
      By experiment do you mean in a lab or in a planet, The latter would be a bit too hard to do. Surely the former has been done?”

      Whether fair or not, it’s true, which is enough for me.

      No, the former has most definitely not been done. It’s models and strident hand waving all the way. There are precisely no experiments showing an increase in warming by interposing CO2 between a radiative source and target. Tyndall, his contemporaries, and everyone after, showed that all gases absorb some radiation, and warm up as a result. Even Tyndall calibrated his equipment to a nominal absorption of 1 for air from which he had removed both CO2 and H2O.

      As Tyndall and others pointed out, gases absorb infrared, for example, preventing this energy from reaching its intended target. When the gas susequently cools, it radiates in all directions, so the target still remains cooler compared with no gas in the way of the radiation.

      And this is what we see on the Moon, and in laboratory experiments.

      Real scientists are aware of this, pseudo scientific Warmists, by and large, are not. Some are, but it is too embarrassing to admit a certain amount of gullibility, I guess.

      The misdirection in regard to emission and absorption spectra is another example of “sciencey” ignorance. You can look up the conditions for establishing these spectra, in depth, if you wish. An empty CO2 cylinder and a CO2 cylinder charged to 57 bar, at 20 C, radiate precisely the same wavelengths. The gas within can be heated by anything above 20 C – friction, induction within the steel cylinder – the wavelength of the photons matters not.

      Your last point about the influence of atmosphere on temperature is correct. The Moon, with essentially no atmosphere, shows how much higher the surface temperature becomes. On the other hand, atmosphere, like any insulator, reduces the rate at which the Earth loses its internal heat.

      So no, no experimental support for any “warming” effects of CO2. No chance of buying a vacuum flask made better by replacing the vacuum with CO2. It doesn’t work that way.

      You can make up your own mind, obviously.

      Cheers.

  17. So, just to be clear, we’ve emitted – to date – around 550GtC. This analysis is suggesting that we could emit another 450GtC and warm by only another 0.1 to 0.2C? Is that a fair summary?

    • No, it is not a fair summary! For the 2010-19 decade, cumulative post 1870 CO2 emissions are about 550 GtC, and the projected GMST rise per my model is 0.9C. When cumulative emissions reach 1000 GtC (ruling out RCP2.6), it is 1.4C (slightly more with RCP8.5 CO2 emissions, if non-CO2 forcing is also as per RCP8.5). That is a further rise of 0.5C, not 0.1 to 0.2C..

      • Nic,
        Okay (and you still wonder why I regard you as a pedantic nitpicker ). The point, though, is that we could almost our double our emissions, and your model suggests that we will only warm by around half of what we have so far; that is essentially what you’re suggesting, right? We could avoid arguing over reasonably small fractions, like 10% or so.

      • To take this a bit further. At current emission rates, we could emit a further 450GtC in about 45 years. If so, your model suggests that decadal warming (on average) can’t really exceed about 0.1C/decade, assuming we follow that type of pathway. The 50 year trends in all the current datasets (1965-2015) are all above 0.15C/decade, so you’re essentially arguing for a decelaration, except for maybe your RCP8.5, which might just about match this – I think?

      • Well, since other commenters are being “pedantic nitpickers” I’d like you to substitute K for C degrees since another C (carbon) is used elsewhere in the formula.

      • Ken,

        Further down the thread Nic has thanked you for spotting the error he made with units, and admitted he made a silly mistake. Meanwhile here you are calling him a “pedantic nitpicker” for pointing out that you understated his case by more than a factor of 2 (0.5C compared to 0.1 – 0.2C).

        That anger’s really starting to get to you, isn’t it?

        Stay classy.

      • stevefitzpatrick

        Ken Rice,
        “(and you still wonder why I regard you as a pedantic nitpicker )”

        Civil and on topic, right?

        If there is a significant (eg 0.2C) pseudo-cyclical component of the temperature rise over the 1965 to present period, then that will lead to a substantial overestimate of future warming. It’s more informative to look at the entire historical instrument record.

      • Steven Mosher

        Attp
        As with all guest posts, please keep your comments relevant and civil.

      • ATTP,
        “At current emission rates, we could emit a further 450GtC in about 45 years. If so, your model suggests that decadal warming (on average) can’t really exceed about 0.1C/decade, assuming we follow that type of pathway. The 50 year trends in all the current datasets (1965-2015) are all above 0.15C/decade”

        Your analysis ignores the facts that:
        a) the increase in CO2 forcing was a lower proportion of total anthropogenic forcing in the past 50 years than it is expected to be in the next 40-50 years, at least for RCP4.5 and RCP6.0;

        b) the GMST trend over the last 50 years was affected both by internal multidecadal variability – the NOAA AMO index had a strongly positive trend over 1965-2014 – and by volcanic forcing being much more negative (6x stronger per AR5 estimates) in the first 30 years of the period than in the last 20 years, when there were no major volcanos; and

        c) CO2 forcing is logarithmically related to CO2 concentration, so if the airborne fraction of CO2 stays constant the second 500 GtC will cause a significantly lower increase in forcing, and hence in warming, than the first 500 GtC.

      • Nic,

        Your analysis ignores the facts that:
        a) the increase in CO2 forcing was a lower proportion of total anthropogenic forcing in the past 50 years than it is expected to be in the next 40-50 years, at least for RCP4.5 and RCP6.0;

        No it doesn’t really, and it wasn’t really an analysis as such. I was simply pointing out that your result suggests that warming will have to be slower , in future, than the current long-term trend? Right?

        the GMST trend over the last 50 years was affected both by internal multidecadal variability – the NOAA AMO index had a strongly positive trend over 1965-2014 – and by volcanic forcing being much more negative (6x stronger per AR5 estimates) in the first 30 years of the period than in the last 20 years, when there were no major volcanos; and

        I love how certain you seem to be about things. However, what you say does not change that your analysis is suggesting that warming in the coming decades will be slower than it’s been – on average – over the last 50 years. You also appear to be ignoring that the best estimate for the anthropogenic contribution since 1950 is “slightly more than all of it”.

        CO2 forcing is logarithmically related to CO2 concentration, so if the airborne fraction of CO2 stays constant the second 500 GtC will cause a significantly lower increase in forcing, and hence in warming, than the first 500 GtC.

        Yes, this is obvious. However, what seems to be the case is that your result will be reasonable if climate sensitivity is on the low side of the range and if carbon cycle feedbacks are also on the low side of the range. If this does turn out to be the case, that would be great, but – once again – you seem to willfully ignore that there is a great deal of information suggestion that it may not be the case. If wishes were horses ……

      • ATTP, so you don’t do analyses, you shoot from the hip and depend on “what ifs”.

        You’re wasting everyone’s time, and Nic is going above and beyond to deal with your sniping.

      • so you don’t do analyses, you shoot from the hip and depend on “what ifs”.

        I think you’re confusing me with Nic.

      • ATTP,
        ‘You also appear to be ignoring that the best estimate for the anthropogenic contribution since 1950 is “slightly more than all of it”.

        Not at all.The AR5 best estimate was for the anthropogenic contribution over 1951-2010. Over that period, per AR5 the trend in volcanic forcing was zero.
        You referred to the period from 1965 on. Over 1965-2014, per AR5 (extending estimated forcing from 2011 to 2014) the linear trend in volcanic forcing was strongly positive – it was about 30% of the trend in anthropogenic forcing.

      • I think it’s time for the mods to step in to put a muzzle on Ken for the good of his own health. Hubris is taking over, yet again.

      • Nic,
        Okay fine, I’ve already been told off once for calling you a pedantic nitpicker, so I won’t do it again. The point, though, which you have yet to actually really respond to is that you are suggesting that the long-term warming trend over the next 40-50 years is likely to be smaller than the long-term trend over then past 40-50 years.

        There are two ways that I guess our discussions could go better. I could try to stop calling you a pedantic nitpicker and you could try to stop being one (I may have just called you one again, but, hey, it’s actually a serious suggestion – your response genuinely make me think that you don’t really want to discuss this, you just want to promote your low climate sensitivity and, now, your low carbon cycle feedbacks.)

      • I was simply pointing out that your result suggests that warming will have to be slower , in future, than the current long-term trend? Right?

        I am beginning to wonder whether he is ever going to answer that question, ATTP.

      • ATTP,

        ” The point, though, which you have yet to actually really respond to is that you are suggesting that the long-term warming trend over the next 40-50 years is likely to be smaller than the long-term trend over then past 40-50 years.”

        What is there to respond to about that? It is obvious from my graph. On RCP6.0, the simulation drend trops by 20% from 0.15 K/decade over 1965-2015 to 0.12 K/decade over 2015-2065. That is what one would expect, given that the forcing trend drops by a bit over 20%.

      • Nic,
        Yes, it is obvious from the graph, but it is at odds with what many expect to happen in the coming decades, hence why I’m asking the question.

        I think I now understand what you’re presenting, so I’ll make a point which you can respond to, or not. You’re selecting a TCR from your own analysis that is at the lower end of the range that many others regard as likely (and that isn’t intended as some kind of IPCC definition of likely). You also appear to be assuming that carbon cycle feedbacks are also on the low end of the range. Consequently, what your analysis suggests is that not only will we warm less than others suggest is likely because the TCR is on the low end of the range, but that the lower carbon cycle feedback means that the forcing will also rise more slowly for the same emission pathway. Given that all these assumption lie within the ranges that are regarded as reasonable, presumably this is all possible. However, that it is possible does not mean that it is likely. Showing that we may warm less than is expected is that not the same as showing that we will warm less than is expected.

        I think there is also another issue. As I understand it RCPs are concentration pathways from which emission pathways are then determined. Presumably here you’re using the emission pathways, not the concentration pathways.

        Something that would be interesting to see is what you would get from your model if you assumed the TCR were higher (say 2C). The reason I ask is that it would be interesting to see the impact of your carbon cycle assumptions.

      • I was simply pointing out that your result suggests that warming will have to be slower , in future, than the current long-term trend? Right?

        Looks to be the case. The average annual rate of increase in RF in the past fifty years is higher than it has been for the last decade, and slight slowdown in rate from the largest contributor, CO2:

      • > What is there to respond to about that?

        That the analysis isn’t so incredible as to look specious. To see how plausible it looks, try to come with an analysis with even lower CS and carbon sinks. If you can’t, this would show something about the lowest bounds lukewarm ingenuousness on the market.

        More generally, how an analysis that selects the lukewarmest bounds can become an argument regarding the claim about “better” estimates.

      • and Then There’s Physics: Okay (and you still wonder why I regard you as a pedantic nitpicker ).

        Aiming for accuracy is always welcome.

      • ATTP,
        “You’re selecting a TCR from your own analysis that is at the lower end of the range that many others regard as likely (and that isn’t intended as some kind of IPCC definition of likely). You also appear to be assuming that carbon cycle feedbacks are also on the low end of the range. ”

        I make no such assumptions. The TCR, ECS and carbon-cycle parameters are simply what are required so that the model’s simulated global temperature, heat uptake and carbon-cycle changes since preindustrial match the observational estimates given in AR5 (HadCRUT4v4 in the case of GMST). The parameters were determined by an optimization routine.

        ” As I understand it RCPs are concentration pathways from which emission pathways are then determined. Presumably here you’re using the emission pathways, not the concentration pathways.”

        No, you’ve got it the wrong way round. The RCP concentration pathways are determined from the RCP emission pathways, using a single EMIC. See Meinshausen et al 2011. My model uses the RCP emission pathways, but the CMIP5 ESM results in my figure and Figure SPM.10 use RCP concentration pathways and diagnose, in each CMIP5 model, what emission pathways would produce those concentration pathways.

      • Nic,
        You really are very keen to not get the point, aren’t you? Is that intentional, or do you not realise that you’re doing it?

        I make no such assumptions. The TCR, ECS and carbon-cycle parameters are simply what are required so that the model’s simulated global temperature, heat uptake and carbon-cycle changes since preindustrial match the observational estimates given in AR5 (HadCRUT4v4 in the case of GMST). The parameters were determined by an optimization routine.

        Okay, fine, change it to you have developed a model that produces a low TCR. This doesn’t change the basic point that this result is a consequence of a model with a low TCR. You really are making it very difficult for me to stick to my pledge.

        No, you’ve got it the wrong way round. The RCP concentration pathways are determined from the RCP emission pathways, using a single EMIC. See Meinshausen et al 2011. My model uses the RCP emission pathways, but the CMIP5 ESM results in my figure and Figure SPM.10 use RCP concentration pathways and diagnose, in each CMIP5 model, what emission pathways would produce those concentration pathways.

        Well, I don’t want to argue about whether or not they are concentration pathways, or emission pathways (my understanding is that GCMs use concentration pathways), but again you seem to have chosen to entirely miss the point (this can’t be coincidence). You are using emission pathways, not concentration pathways. The reason the concentration rises more slowly than in other models is partly because of the TCR being on the low end of the range, and partly because of your assumption about carbon cycle feedbacks being on the low end of the range. Agreed?

        So, I’ll repeat again. That you can show that this is plausible/possible, does not mean that it is likely and certainly does not rule out that we could warm much more than you seem to be suggesting. Of course, I fully expect this result to make an appearance in one of Matt Ridley’s forthcoming articles.

        Also, I would still be interested to know what happens in your model if you were to try and set the TCR to be something like 2C. I’m interested to see how your assumptions about the carbon cycle feedbacks influence the results.

      • Turbulent Eddie: The average annual rate of increase in RF in the past fifty years is higher than it has been for the last decade,

        How is the rate of change of radiative forcing known back to 1900? Also, is the vertical axis mislabeled? Oughtn’t it be W/m^2/year?

      • stevefitzpatrick

        Nic Lewis,
        “the CMIP5 ESM results in my figure and Figure SPM.10 use RCP concentration pathways and diagnose, in each CMIP5 model, what emission pathways would produce those concentration pathways.”

        If that is true, then it is about the nuttiest thing I have heard in a while. The emissions pathways ought to be driving the concentration pathways in the GCM’s, not the other way around. The emissions pathways are based on specified policy and economic choices which have nothing to do with the GCM’s. I don’t see how it makes any sense at all for the concentration pathways, generated from a single model and the specified emissions pathways, to be turned around and used to generate a completely different and unique emissions pathways using the individual GCMs. The circularity here is exceeded only by the irrationality; the emissions pathways are fixed.

      • stevefitzpatrick

        Ken Rice,
        “again you seem to have chosen to entirely miss the point (this can’t be coincidence)”

        Civil and on topic? Two snide comments in a single short line.

        “That you can show that this is plausible/possible, does not mean that it is likely and certainly does not rule out that we could warm much more than you seem to be suggesting.”

        I think you have this a bit backwards. Nic finds a model which best fits the historical data (using some AR5 best estimates) and then makes projections of warming for each emissions pathway. These turn out slower than the warming projected by CGM’s. It would be more accurate to just say Nic’s model suggests slower warming is more likely than faster warming.

        Is faster warming possible? Sure, Nic could be wrong. It is fair to ask how the optimization of fit to the data in Nic’s model was done so that you can judge how tightly constrained the climate sensitivity is by the optimization process (and any assumptions which go into it), and so better judge the uncertainty in his projections. I don’t think it is fair to say his result is ‘not likely’ just because it disagrees with GCM estimates. Nic’s estimate for ECS lies within the AR5 “likely range” of 1.5C to 4.5C; it seems to me that actually showing his result is ‘not likely’ requires a lot more than pointing at other estimates which are higher.

        The probability of much faster warming (eg. the GCM pooled estimate) is a different question, and one that requires critical evaluation of the assumptions (parameterizations) and uncertainties in each model. Of course, I expect the trajectory of warming over the next three decades will sort this all out, because there is a big difference between the GCM average warming (about 0.24C per decade IIRC) and Nic’s estimates (about 0.12C per decade), and because the emissions pathways have no significant impact on projected warming for the next few decades for either GCM’s or Nic’s model, so today’s “policy choices” will make little difference over that period. If warming follows a path of ~0.12C per decade, as Nic’s model projects, then I think relatively low climate sensitivity will be difficult to refute. If warming follows a path of ~0.24C (or more) per decade, then relatively high climate sensitivity will be difficult to refute.

      • Steve,

        Civil and on topic? Two snide comments in a single short line.

        I only said I would try to not call Nic a pedantic nitpicker if he actually tried to not be one. He doesn’t appear to be trying very hard.

        It would be more accurate to just say Nic’s model suggests slower warming is more likely than faster warming.

        The problem is that there are other models that also fit the historical data and that show faster warming in future. If we’re interested in understanding what is likely to happen then we should consider everything, not just chose what seems most appropriate. This isn’t really about finding some model that gives us a result that we happen to like, it’s about actually understanding how our climate is likely to respond to increasing anthropogenic forcings.

        Of course, I expect the trajectory of warming over the next three decades will sort this all out

        I expect so too. However, if the faster warming does materialise, and if 2C is some kind of reasonable target, then we could use up most of our carbon budget in the next 3 decades. Therefore, I actually hope that Nic’s results are closer to reality than the other results.

      • Also, is the vertical axis mislabeled? Oughtn’t it be W/m^2/year?

        Yes, it should.
        Update.

      • Typical Kenny.

        He says one thing and then changes his argument after being shown to be wrong.

        Professor, don’t you have something productive to do, like grading end of term papers?

      • @ ATTP
        “and you still wonder why I regard you as a pedantic nitpicker”

        You say that as if it is a bad thing. Pedantic nitpicking is at the foundation of science.

      • Right – so after a huge amount of to and fro, in which Nic has answered every one of Ken’s substantive questions (despite Ken’s continued contempt), Ken’s position has boiled down to some hard-core pearl-clutching because the model Nic has presented doesn’t agree with some other models Ken has previously seen.

        Yet still Ken wonders why he gets such a hostile reception around here, even if we are a pack of deniers. He really should take a leaf out of Nick Stokes’ book.

      • JA,

        so after a huge amount of to and fro, in which Nic has answered every one of Ken’s substantive questions

        I don’t think he has, but that’s not really all that important, as I think I now understand what his analysis is doing. If everything happens to be low, we’ll warm less. As far as I can tell, it’s still within the range presented by the IPCC, and – as I’ve already – clearly a plausible result. However, that doesn’t make it somehow likely.

        (despite Ken’s continued contempt), Ken’s position has boiled down to some hard-core pearl-clutching because the model Nic has presented doesn’t agree with some other models Ken has previously seen.

        I think you may be confused as to who’s doing the pearl-clutching “oooh, he said ‘pedantic nitpicker’, what a meany!”. As I’ve said already, this result appears plausible, given that we can’t rule out low climate sensitivity and can’t rule out lower carbon cycle feedbacks. If Nic is simply pointing out that this is possible, then sure, that’s pretty obvious. If he’s suggesting that it’s somehow likely, then I do not think he’s done any such thing.

        He really should take a leaf out of Nick Stokes’ book.

        Indeed I should, and I do strive to. I just fail more often than I should. I’m not alone in that regard (pot, kettle, and all that). In fact, I apologise to Nic for calling him a pedantic nitpicker.

      • > Pedantic nitpicking is at the foundation of science.

        Not really. First, because it may not correlate to historical facts. Second, because there may not be no such thing as a “foundation.”

        How is “foundation” still a thing in contrarian networks only illustrates the kind of unloseable skepticism they usually display.

    • ATTP writes

      “The problem is that there are other models that also fit the historical data and that show faster warming in future. If we’re interested in understanding what is likely to happen then we should consider everything, not just chose what seems most appropriate.”

      Specifically which model do you believe has reasonably accurately matched observed conditions for warming? How has that same model done if matching observed changes on annual rainfall at different places around the planet. What level of warming does that model forecast over the next 20 years?

  18. Also, isn’t this wrong

    TCRE of ~1.15°C/GtC,

    I presume you mean 1.15oC/1000GtC?

  19. JCH ?
    where are you, with your warming oh so true?
    No comment on November’s record heat wave.
    Was it an Al Gore moment due to the climate conference?
    Or did it just forget to go up in November despite your El Nino?

    • What are you on about? Moyhu has NCEP at 1.028 as of November 28. Do you think that’s unusually cold?

      • Did it break a record?

      • Oh, I guess it’s slightly possible it could.

      • Given low climate sensitivity and the predicted deceleration in warming, I think it’ a miracle this November didn’t bring the freakin’ glaciers sliding down from Canada.

      • November produced a report that the Antarctic is actually gaining ice but those glaciers are a long way from Canada fortunately.
        I guess you win on the warmest GISS year on record and adjusted UAH.
        Care to predict a warmest December?
        “Oh, I guess it’s slightly possible it could.”
        If it was not an El Nino Year would you still have been able to comment?
        I would like it better if you also admitted the cold facts and records when they occur.

      • Earth adds ice to Antarctic as needed for temperature regulation in the southern hemisphere. Earth adds ice to Greenland and mountain glaciers as needed for temperature regulation in the northern hemisphere. Both use the temperature that Polar oceans freeze and thaw for a thermostat and both have the same set point.

      • Lol.

        ENSO is part of the climate system. 2014 was a warmest year when there was no El Nino. Can there be a warmest month when there is no El Nino? Yes, there can be. May, August, Sept, Oct, and Dec 2014 were all record warmest months in the GISS record. Just as examples.

        Your problem is there is no cold in your cold cycle. This cycle only pedals uphill; it never pedals downhill in any old-fashioned sense. The strangest darn set of cycles ever seen. The last genuine cold snaps in the GMST were 1900 to 1910, and 1942 to 1952. That how few bullets you clowns have in your magazine. The powder is so old it might not even work.

        October was the warmest month in the entire GISS record. Sorry, I’m not really feeling very uncomfortable about this is November fails to break that record. November 2015 could be the warmest November in the GISS record. Looks like it has a good shot at it. That would be pretty high cotton for the month of November.

        Antarctica gaining/losing ice is not a big deal. The seawater is there. How it got there is all that nonsense comes down to. It came from somewhere. The Zwally study does not erase it. The seawater is still there.

        December 1 is hot. What did you expect? That it would be cold? Good grief.

      • UAH 0.33 in November [from Jim2] down thread.
        No comment JCH on this record warming?

        “December is going to be very warm. It does not have to set a record to cook your goose”.
        So if it is less than 0.33 you will be wrong?

        “Zwally is not a big deal. First, you do not know if the other studies are wrong, or if Zwally is right. If Zwally is right, them he’s also probably right that that the situation is likely to go the other way in the coming years.”

        Meaning no amount of facts will convince you?
        What if Zwally is right, what if TCR is low, what if the temps drop after El Nino, what if the buoys were adjusted on order, still not prepared to try thinking?
        I’m prepared to admit AGW when the temps align with CO2 rise. What would be your breaking point?

      • UAH does an inaccurate job of estimating the surface temperature, as the chief scientist at RSS has honestly admitted of their product, which UAH was recently “adjusted” to be more like. They went from more accurate than RSS to as inaccurate as RSS. They used to call that “smooth move exlax.”

        Maybe a congressional committee will investigate.

        So I do not take UAH seriously? Why would anybody take centigrade fiction seriously?

        If the surface anomaly does not go down after the current El Nino, I would say it’s time to blow this popsicle stand because the oceans could eventually boil.

        The current pause-killer heatwave began 2012. The GISS trend is .07C per year, Your inaccurate friend, RSS, is cooking at .05C per year. They are both big numbers ’cause it really is a heatwave.

      • Satellite temps have diverged from near-sfc increasingly since 2000. Many arguments as to who is more correct. Both have weaknesses. Both have adjustments. This is why I prefer to use WTI. You can’t just chuck out the one you don’t like.

        NCAP CFS/ver2 model initializations since 2000 track closer to satellites. Doesn’t mean they are right… but CFS is initialized every hour with best available data of all types.

      • “UAH does an inaccurate job of estimating the surface temperature”

        No it doesn’t.
        UAH doesn’t estimate surface temperature at all.
        UAH estimates the temperature anomalies of the lower troposphere.

        Ground based thermometers do an inaccurate job of estimating surface temperature.

      • Yes, GISS and HadCRUT4 are most likely too low, and, hopefully, will soon be corrected upwards.

      • They always are. I am still looking for a new version of GISS or Hadcrut that had a lower overall warming trend than the previous version. Any help? I’ve been told such a thing does not exist.

    • “Antarctica gaining/losing ice is not a big deal. The seawater is there.”
      ????
      To clarify.
      The continent of Antarctica in November was the subject of a study by Zwally that net ice, the stuff on land that makes glaciers, was increasing rather than decreasing as previously reported by Grace studies using wrong algorithms [they had it right that ice was increasing but then changed the algorithms a bit like the recent sea surface temp fiasco].
      Hence it is a very big deal.

      using your logic on the sea ice, different subject one could say ” The Arctic gaining/losing ice is not a big deal. The seawater is there.”
      Could I quote you on that?

      “December 1 is hot. What did you expect? That it would be cold? Good grief.”
      I did ask
      “Care to predict a warmest December?”
      not a very considered answer. or do you want to wait until the end of December to make a prediction?

      • Zwally is not a big deal. First, you do not know if the other studies are wrong, or if Zwally is right. If Zwally is right, them he’s also probably right that that the situation is likely to go the other way in the coming years.

        He also agreed with the amount of ice melt other studies found.

        The only real ramification of the Zwally study is it puts the balanced sea level budget back out of balance..

        Which means my pet, that steric sea level rise has been underestimated, into contention to be correct.

      • December is going to be very warm. It does not have to set a record to cook your goose.

      • December is going to be very warm.

        In the NH temperate and polar regions, December is going to be cold.
        In some areas, December will not be as cold as normal.
        In the SW US, December will likely be colder than normal due to El Nino.

      • n the NH temperate and polar regions, December is going to be cold.
        In some areas, December will not be as cold as normal.
        In the SW US, December will likely be colder than normal due to El Nino.

        Lol. So what? Meaningless.

      • Well if the El Nino is like ’97-’98 then 2016 should be hotter than 98.

      • The 2015-16 EL Nino is going to be like itself. It cannot be like 1997-98. For one thing, 97-98 came at the end of a long downturn in the PDO trend. 2015-16 has happened after a steep ramp up of the PDO. The dynamics are very different. There is way more ACO2 in the atmosphere. The upper ocean is much hotter.

        I don’t think it is a given that 2016 will be hotter than 2015.

        But the predicted disaster for warmunistas… that a La Nina could restore the pause… haha. La Nina heats the oceans. Oh my, that will hurt me a lot. I’ll cry through the whole thing.

        This is my coin: head you lose; tails you lose. Sorry.

      • Lol. So what? Meaningless.

        Just correcting your error.

        December will not be warm.
        December will be cold.

  20. Cumulative anthropogenic (i.e., human-emitted) emissions of CO2 from fossil fuel use are said to be a major cause of global warming, yet human emissions per year are a slight fraction of the total carbon production [? <2%].
    Hence it would seem the major cause of global warming is the natural production of CO2 from burning of forests and natural vegetation decomposition, 98%. Given that the warming effect of this CO2 in the atmosphere is said to be for up to 500 years** it would seem the main cause of future global warming is 98% due to natural CO2 production.
    The "…and Then There's Physics
    we’ve emitted – to date – around 550GtC."
    comment ignores the obvious how many GtC to date has the earth produced?
    roughly 11000 Gtc.
    I fail to see how a mere 2% extra addition of CO2 load over this time period with numerous sinks of "infinite" capacity can be said to have any meaningful correlation to temperature estimates

    **As University of Washington scientist David Archer explains, this “long tail” of absorption means that the mean lifetime of the pulse attributable to anthropogenic emissions is around 30,000 to 35,000 years.
    Zeke Hausfather article , Mosh
    Can you tell Zeke it means mean lifetime of 98% of the pulse attributable to natural emissions is also around 30,000 to 35,000 years.
    Just to keep it polite and all.

    • See, now it’s perfectly clear why you’re a scientist. You don’t miss anything. Nothing. We were hoping nobody would notice the obvious problem there. I’m so impressed with Australians. I figure now that just 2 contrary Australians could replace the entirety of NASA.

      • See, with just a little time and effort you math has improved some wot.

      • Yes, I looked up and counted 11,000 GTC floating up there and gradually declining over 35,000 years to zero as it turned into rock. Just a few months ago, I could not count to 11,000. It’s a miracle.

      • The Climate research part of NASA could go away and no one would notice.

      • I think understanding why NASA researches climate would helpful. Maybe it was so they could go to the moon, or so our military could hit the broad side of a barn.

      • If NASA really studied climate, that would be good. Since they mostly study CO2 sensitivity and not natural variability, that part of NASA should be abolished and replaced with real skeptic scientists. Keep the people who gather data. Get rid of the ones who “adjusted” the data.

        I worked for NASA from 1963 to 2007. I am sick about some of the garbage they call science. We did contact Bolden, the head of NASA, with some of our outrage.

      • I think understanding why NASA researches climate would helpful.

        NASA stands for Aeronautics and Space. That should include Climate, if properly conducted.

      • “I think understanding why NASA researches climate would helpful.”

        That is a good point. It is not NASA’s core compentancy.

      • Flying through the atmosphere is core.

    • angech,
      Hmmm. You do realise that prior to us starting to emit CO2 through the burning of fossil fuels, the natural sinks were essentially in balance. In case you don’t understand what this means, it means that as much CO2 ws coming out of the oceans as going in. As much was coming out of atmosphere as going in. And as much was coming out of the biosphere as going in. The reason it has been rising is that we dug up and started burning fossil fuels, a consequence of which is that CO2 gets emitted into the atmosphere. Since fossils are not being created at nearly the rate at which we’re burning them, this means that there is a net flux into the system, causing CO2 levels to increase in the atmosphere, biosphere and oceans.

      • If that is true ATTP, why has there been such big swings in atmospheric levels in co2 concentrations in the geologic history? Seems that if everything in nature was always in perfect balance as you suggest, climate should have been quite stable throughout, correct?

      • Firstly, I was referring to the period during the Holocene prior to the start of our emissions, rather than all of geological history. However, the Milankovitch cycles (which see a change in CO2 from about 180ppm to about 280ppm) are thought to be triggered by orbital variations, that then lead to warming that is a combination of albedo changes and changes in atmospheric CO2 that is released (or reabsorbed) as we warm (cool). There is a relationship between temperature and atmospheric CO2, but it is around 20ppm per degree and is far too small to explain the rise that we’ve seen since the mid-1800s.

      • The latest instance: a report published in the February issue of the journal Geosphere, offering a plausible explanation for swings between long stretches of greenhouse warming and dramatic cooling over millions of years.

        The culprit, said lead author Cin-Ty Lee of Rice University in an interview, appears to be the ebb and flow of eruptions from volcanic mountain chains around the globe, which alternately pump heat-trapping carbon dioxide into the atmosphere and allow it to be re-absorbed by rocks and living things.

        While these changes happen far too slowly to have any bearing on the current, human-caused episode of global warming, they do help scientists to understand the relationship between carbon-dioxide concentrations in the atmosphere and global temperature changes.

        Caveat, I did not confirm the author is a contrary Australian. If not, you’ll have to discount the science.

      • there is a net flux into the system, causing CO2 levels to increase in the atmosphere, biosphere and oceans.

        Yes, carbon based life forms ( you, me, and pretty much all life except methane eating ocean bed ooze ) which exist only by the grace of CO2 in the atmosphere and oceans seem to do better with more CO2 available. Fancy that.

      • Cli-sci, such a new sci, so much we don’t know, so many
        failed presumptions …
        / model temperature projections,
        / feedback problems,
        / temps failing to correlate with CO2 increase,
        / hot-spot fingerprint …

        Hot spots – volcanoes… CO2 has been seeping into the
        planet’s atmosphere for as long as there has been one.
        Recent estimates of how much degassing are surprising
        and there’s still more to learn in the ocean deep …
        http://www.livescience.com/40451-volcanic-co2-levels-are-staggering.html

      • Wow, TE, you really do seem to be ascending the denialist ladder. You’ll be a grand master soon enough.

      • Steven Mosher

        As with all guest posts, please keep your comments relevant and civil.

      • As with all guest posts, please keep your comments relevant and civil.

        Mosher’s automatic comment-bot is doing a better job with his comments than the real thing. Isn’t technology amazing?

      • There is a relationship between temperature and atmospheric CO2,

        Duh! The oceans are a huge carbonated drink and higher temperature does support higher vapor pressure of all gases that dissolve in water.

        open a cold and a warm carbonated drink and spew the difference.

      • The CO2 does not warm the canned drink.

      • ATTP,

        You are missing the point: independent of the source, the atmospheric residence time is the same. So a residence time of 30000 years is absurd based on the fact that the gigantic natural production does not reside in the atmosphere any more. Residence time is about 30 years as can be assessed from the C14 nuclear testing spike.

        Your concept of a pulse of CO2 that cannot be geologically stored is not based on residence time, but on the assumption that geological carbon storage is constant and equal to current natural production. That is an interesting proposition. Nic Lewis’ model is a first attempt to model the uptake side as well as the production side. Contrary to your implicit assumption, the biological and geological mechanisms that sequester CO2 are probably proportional to atmospheric CO2. We have not seen that to date because there are confounding factors. For example, the recent CO2 measurements from satelites indicate larger than expected CO2 sources from the tropics. These unexpected sources may hide the already increasing sinks.

        It will be interesting to learn the actual uptake response to ppm CO2.

      • and Then There’s Physics: Wow, TE, you really do seem to be ascending the denialist ladder. You’ll be a grand master soon enough.

        Could you supply a quote in which TE denies some science?

      • Matthew,
        Oh please. Anyone who plays the “we need CO2” card deserves that. TE might just be trying to sound stupid, but he still deserves it.

        wkernkamp,

        Residence time is about 30 years as can be assessed from the C14 nuclear testing spike.

        Not for an ehanced pulse of CO2, it can’t.

      • and Then There’s Physics: Anyone who plays the “we need CO2” card deserves that. TE might just be trying to sound stupid, but he still deserves it.

        What he actually wrote was that we do better with more CO2, which is certainly defensible on the evidence. No one “deserves” to be labeled “denialist” (and related terms) while hewing close to the scientific evidence.

      • Matthew,
        If TE is unhappy with my comment, then he’s welcome to complain to me.

      • Oh please. Anyone who plays the “we need CO2” card deserves that. TE might just be trying to sound stupid, but he still deserves it.

        Hi ATTP.

        1. You are a carbon based life form that would not be alive were it not for carbon dioxide in the atmosphere.

        2. Plant life on land and in the oceans store chemical energy through a process scientists call ‘photosynthesis’.

        3. Higher amounts of available carbon dioxide result in greater plant growth, apparently both on land and in the oceans.

        4. Higher amounts of available carbon dioxide result in greater crop yield.

        5. Higher amounts of available carbon dioxide result in reduced land based plant water loss because of more effective respiration.

        6. Phytoplankton are the base of most ocean food chains.

        7. Phytoplankton are apparently growing in abundance with increased CO2.

        Ignoring or denying these facts and factors as benefits to both humans and the biosphere is not part of an inclusive objective assessment of risk/benefit.

      • Ignoring or denying these facts and factors as benefits to both humans and the biosphere is not part of an inclusive objective assessment of risk/benefit.

        Hmmm, but highlighting simplistic truisms without any context isn’t either.

      • and Then There’s Physics: Matthew,
        If TE is unhappy with my comment, then he’s welcome to complain to me.

        So he is. And so are we all. You ought to apologize for the gratuitous insult. It pollutes the forum.

      • You ought to apologize for the gratuitous insult. It pollutes the forum.

        How long have you interacted on forums that discuss this topic? I didn’t think you were that new? An alternative might be to discourage people from posting denialist talking points. My current working hypothesis is that those who most object to them being pointed out, are simply trying to get away with talking nonsense without being criticised.

      • Hmmm, but highlighting simplistic truisms without any context isn’t either.

        Sure it is.

        You noted that CO2 is going into the biosphere.

        I noted that CO2 going into the biosphere is a pretty good objective indicator of benefit to life on the planet.

      • An alternative might be to discourage people from posting denialist talking points.

        Are you a photosynthesis denier?

      • I noted that CO2 going into the biosphere is a pretty good objective indicator of benefit to life on the planet.

        Apart from that probably being nonsense, a good point.

      • Are you a photosynthesis denier?

        I guess we’re even now? :-)

      • ==> “So he is. And so are we all. You ought to apologize for the gratuitous insult. It pollutes the forum.

        The selectivity as to when people comment on gratuitous insults, is really quite amusing.

      • …and Then There’s Physics | December 1, 2015 at 7:14 am | Reply
        “prior to us starting to emit CO2 through the burning of fossil fuels, the natural sinks were essentially in balance.”

        Can I use wkernkamp”s excellent, on the money response?
        “Your concept of a pulse of CO2 that cannot be geologically stored is not based on residence time, but on the assumption that geological carbon storage is constant and equal to current natural production. However the biological and geological mechanisms that sequester CO2 are probably proportional to atmospheric CO2. ”

        further he said
        “ATTP, You are missing the point: independent of the source, the atmospheric residence time is the same. So a residence time of 30000 years is absurd based on the fact that the gigantic natural production does not reside in the atmosphere any more. Residence time is about 30 years as can be assessed from the C14 nuclear testing spike.”

        Your reply
        …and Then There’s Physics | December 1, 2015 at 1:43 pm |
        “Not for an enhanced pulse of CO2, it can’t.”

        is unworthy of you, a dogmatic statement that ignores all the scientific facts. To recap CO2 production naturally from fires, decaying vegetation, respiring non plant life forms and volcanoes varies immensely from year to year far more than the “enhanced pulse” of human activity.
        The sinks vary and cope with it .
        Otherwise,
        Taking the volcanoes alone, over the last 30,000 years, at a rate of 8 pulses per century and 1 megapulse [Krakatoa] every thousand years either the only reason we have any CO2 is due to pulses or else why is our CO2 level so low with all the contributions from so many none human pulses for so many millenia?.

      • and Then There’s Physics: An alternative might be to discourage people from posting denialist talking points.

        Even when the “denialist talking point” is a true statement, as it was in this case? It might be “simple” and it might be a “truism”, but his statement that more CO2 is better is supported by evidence. When a “denialist talking point” is based on evidence, reminding people of it is a good idea, so it does not get forgotten. Are you trying in some indirect way to tell us that his claim is false? Is it irrefutable? Have you a refutation? Did GWPF err when compiling the evidence that CO2 increase since 1880 is beneficial on the whole?

      • and Then There’s Physics: How long have you interacted on forums that discuss this topic?

        A common enough tactic is to switch from debating (or at least addressing) propositions and evidence to insulting writers (“denialist”, etc) and insulting propositions (“talking point”, etc.) Usually it happens, as here, when someone encounters an irrefutable proposition inimical to the case he or she is trying to support. There are other evasions, such as “shifting ground” (revising what was being supported), and changing the subject altogether. People all over the spectrum engage in these evasions and camouflage. I raised the issue here because TE is consistently one of the more informative writers.

      • I raised the issue here because TE is consistently one of the more informative writers.

        Indeed he is. That’s why it is sometimes a little frustrating when he chooses to promote some kind of trivial truism that is typically regarded as simply a denialist talking point. Appearing to address apparent alarmism, by promoting Panglossian optimism, isn’t particularly productive.

      • > Usually it happens, as here, when someone encounters an irrefutable proposition inimical to the case he or she is trying to support.

        On the other hand, an irrefutable proposition fails to qualify as a scientific one. Not that it matters much, Nic’s proposition is for lukewarm consumption anyway. We can almost predict Matt King Coal will pick it up in a small unit of time.

        As long as it’s the lowest ball freedom fighters can point and shoot in the trickle-down information economics of their networks, anything goes.

      • You have an elegant way of saying nothing, willy.

      • aTTP: That’s why it is sometimes a little frustrating when he chooses to promote some kind of trivial truism that is typically regarded as simply a denialist talking point. Appearing to address apparent alarmism, by promoting Panglossian optimism, isn’t particularly productive.

        If the evidence supports the proposition that increased CO2 (over the ranges discussed here) is beneficial to life (evidence summarized recently by GWPF, and not well refuted so far as I am aware), then the proposition is not “simply a denialist talking point”, even if it is “typically regarded” as such. Who cares about typically, anyway? certainly not you. And when the proposition is supported by the evidence, it is not “Panglossian” optimism.

        It is not a “trivial truism” that increased CO2 is likely beneficial to life on Earth, the proposition that TE started with and that you called a denialist talking point without agreeing with it or disagreeing with it. Do you agree that the balance of the evidence supports the proposition that increased CO2 is likely beneficial to life on Earth? Calling it a “talking point” evades the issue.

      • willard: On the other hand, an irrefutable proposition fails to qualify as a scientific one.

        This one is potentially refutable, if the evidence should turn out that way. It’s irrefutable now because the evidence is that more CO2 has been beneficial. And, fwiw, aTTP has mocked the proposition without attempting any refutation.

      • > It’s irrefutable now because the evidence is that more CO2 has been beneficial.

        You must be joking: not being able to refute any proposition Nic made in that piece has nothing to do with CO2 being beneficial, and everything to do with the fact that they only help him build a model about something that can’t be verified yet, if ever.

        Talk about precision!

  21. COP21 is the setting the stage for the world leaders to make the grand switch from what we knew as the “Industrial Revolution”, which is now on the downside of the development curve, to a new world financial order of “Renewable Energy”. The demand is limitless, the supply just starting. Bill Gates recognizes the opportunity….

    All that is needed is a commercial, viable energy storage device. Plow the development m oney into that and we might be getting somewhere. Wake me up when you get there.

    In the meantime, we will continue to fight over scraps from the dinner table. I would rather understand the entire earth weather system – let’s study the entire system, rather than a small portion of it. Put atmospheric CO2 concentration in perspective.

    But, I’m just a retired practicle Engineer from the US…what do I know about world politics?

  22. Can’t you do this in a simple thought experiment?

    The climate has gone through enormous perterbations in the past and today’s climate isn’t pegged at one extreme or another.

    So obviously the system is stable, which means, here’s the point, that it resists perturbation.

    One perturbation is CO2. It will resist that too, so the sensitivity has to be small.

    This actual simulation includes all the physics correctly, which is not nothing. In fact it’s what the models have to figure in somehow, or discover that they’re no good at the outset.

    • The climate has gone through enormous perterbations in the past and today’s climate isn’t pegged at one extreme or another.

      Some of those perturbations were CO2 related. These past perturbations are consistent with an equilibrium sensitivity of 3C per doubling.

      One perturbation is CO2. It will resist that too, so the sensitivity has to be small.

      Doesn’t follow, and I have no idea what you mean by resist. The only resistence is the Planck response which works through increased, or decreased, temperatures.

      • Doesn’t follow, and I have no idea what you mean by resist. The only resistence is the Planck response which works through increased, or decreased, temperatures.

        The entire system resists, as in Le Chatlier’s principle. The evidence for it is that the climate hasn’t run off to one extreme or the other.

        Otherwise you’d get exponential growth, which turns up as pegging.

        Remember, that this crisis is supposed to happen because of the system reponse reenforcing it. Evidence is, from history, that it resists.

      • rhhardin,
        Again, that does not follow. The climate is in pseudo-equilibrium because the outgoing energy flux matches the incoming energy flux. The outgoing flux depends on the surface temperature and also on the composition of the atmosphere (i.e., the Greenhouse effect). If we change the incoming flux, or change the outgoing flux, then the response is either for the system to warm, or to cool. In doing so, the surface temperature changes and the system will return to a state of pseudo-equilibrium (I say “pseudo” because it’s never in strict equilibrium). The reason it doesn’t lead to exponential growth is because the Planck response is larger (and negative) than the other feedback response (which are typically overall positive), hence a change in temperature can return us to a state of pseudo-equilibrium if other factors change. This does not, however, mean that it will somehow return us to the same state as before.

      • Again, that does not follow. The climate is in pseudo-equilibrium because the outgoing energy flux matches the incoming energy flux.

        The climate system does all kinds of things in response. Clouds occur to me right away, because I know more about air, which I can see. Then there’s god knows what from oceans and ice and plant growth.

        And here we are, at a nice temperate climate after historical perturbations.

      • This does not, however, mean that it will somehow return us to the same state as before.

        The temperature that Polar Oceans freeze and thaw is fixed.

        If Polar Ocean temperatures get above that value, snowfall is turned on, big time and ice on land is replenished until it is sufficient to cool the earth.
        If Polar Ocean temperatures get below that value, snowfall is turned off, big time and ice on land is depleted until it is sufficient to warm the earth.

        Earth temperature is regulated, look at the ice core data. Even the major ice age and warm periods were regulated, just in larger cycles.

        There was always more ice on earth during the cold times and there was always less ice on earth during the warm times. This was not a result of warm and cold, this was a necessary part of the cause. Snowfall is always more during warm times and less in cold times.

        Earth did cool more as ocean circulation changes put more warm tropical water in Polar Regions, supporting more and more cooling ice on land.

    • ATTP,

      The Earth’s surface was once molten. It has cooled. No radiative balance at all, no more than any other body, cooling, has a radiative balance.

      The average surface temperature is apparently around of 288 K, at present. With a white hot core, non Warmist physics shows the Earth will continue to cool.

      You may continue to believe the Earth will stop losing heat, and somehow warm up, but you would be bucking four and a half billion years of Nature’s operation. I don’t like your chances.

      Cheers.

      • Mike,
        I think we’ve discussed this before. It was rather silly last time. I don’t expect it to be different this time.

      • Steven Mosher

        As with all guest posts, please keep your comments relevant and civil.

      • ATTP,

        You wrote –

        “Mike,
        I think we’ve discussed this before. It was rather silly last time. I don’t expect it to be different this time.”

        As usual, you have not produced any facts which disagree with my comment. Do you really believe the surface temperature rises in line with cumulative CO2 emissions? Have you any experimental support for your denialist assertions?

        Here’s a quote from a physicist named Richard Feynman – ““The principle of science, the definition, almost, is the following: The test of all knowledge is experiment. Experiment is the sole judge of scientific “truth.”

        Now you may choose to believe a denier like the Distinguished Professor, Michael Mann, pretend Nobel Prize Winner, or you may choose to believe a real scientist like Richard Feynman.

        I prefer Feynman to Mann. The world has cooled. I know you don’t like it, but you might as well get used to it!

        Cheers.

      • Mike Flynn:

        Your observation about the Earth cooling since the proto-solar system bombardment ended is trivially true — but only if you use a straight-line curve with approximately two data points: 4.3 billion years ago and today.

        You might want to refine your argument a bit before redeploying it.

      • opluso,

        If you agree that the earth has cooled for four billion years, I don’t mind if it’s trivially true, monstrously true, or just true.

        Unlike most others, I don’t believe in cherry picking. Two data points over the longest period gives truth, as far as truth goes. If you believe the Earth will stop cooling, in denial of physics as it currently exists, that would seem more a matter of faith than anything else.

        Large blobs of molten rock having cooled on the surface to below their melting point will not warm up again, no longer how long you leave them in the Sun. If their interior is over 100 C, they will continue to cool. The Earth is one such blob.

        Cheers.

      • I am going to try to help you, Mike. I like Australians. Opluso is correct. Harping on the cooling of the earth over 4 billion years is harping on a triviality. The argument here is over the prospect that increasing ACO2 will cause the current temperature to increase and whether that increase will be of a magnitude that will cause us problems.

      • Don Montfort,

        You wrote –

        “Harping on the cooling of the earth over 4 billion years is harping on a triviality. The argument here is over the prospect that increasing ACO2 will cause the current temperature to increase and whether that increase will be of a magnitude that will cause us problems”

        I’m not sure why pointing out the fact that four billion years of cooling, involving a fall of some thousands of degrees, in spite of high historical levels of CO2, is harping. To a Warmist, facts are trivial, particularly if they involve demonstrable cooling.

        You might notice that Warmists keep predicting warming based on a selective reading of the past. I’m just pointing out that the longest trend is demonstrable cooling, trivial or not. Fact.

        Warmists don’t like facts, apparently, and spend inordinate amounts of resources trying to adjust the past to prove temperatures have risen, A little selective, don’t you think?

        So what have Warmists got? No physics to demonstrate their laughable assertions that CO2 can provide heat where none previously existed. Plenty of real physics to show just the contrary – backed up by experimental results. One might think that the combined brain power of the climatological consensus, backed up by seemingly limitless resources, could devise and carry out experiments to justify their strange beliefs.

        Real physicists have been measuring things such as the charge, magnetic moment, and other properties of a single electron. As an example of reasonable precision, an experimental value of 2.00231930419922 ± (1.5 × 10^-12), differs from the theoretical value by not a lot. It’s still not exact, so experiments go on.

        Warmists work on wild speculation, and cannot seem to agree on anything much, except to keep bleating that it’s worse than they thought. I am not surprised.

        If CO2 creates no increase in temperature on a body heated by the Sun, the amount is irrelevant. The big hot rock on which we live continues to cool. If you want personal warming, reduce internal heat loss by any means you can. Not too much or you’ll die quite quickly.

        CO2 must be good. When we stop producing it personally, we are most likely deceased. I intend to keep producing CO2 as long as I can!

        Cheers.

      • “No physics to demonstrate their laughable assertions that CO2 can provide heat where none previously existed.”

        I am pretty sure that’s not their assertion, Mike. You are forgetting the surface 288K. You just mentioned it above. I am guessing almost all of the surface heat comes from that big ball of gas in the sky, we like to call the sun. If you think it comes from the white hot core, that’s fine too.

        Wouldn’t the CO2 in the atmosphere still have a theoretical effect on the surface temperature? It’s got something to do with radiative physics, Mike. That’s all I know, so I can’t help you any more. Keep at it. You are annoying the crap out of the warmistas.

      • Don Monfortt,

        Thanks for the kind words.

        You wrote –

        “No physics to demonstrate their laughable assertions that CO2 can provide heat where none previously existed.”

        I am pretty sure that’s not their assertion, Mike. You are forgetting the surface 288K. You just mentioned it above. I am guessing almost all of the surface heat comes from that big ball of gas in the sky, we like to call the sun. If you think it comes from the white hot core, that’s fine too.

        Wouldn’t the CO2 in the atmosphere still have a theoretical effect on the surface temperature? It’s got something to do with radiative physics, Mike. That’s all I know, so I can’t help you any more. Keep at it. You are annoying the crap out of the warmistas.”

        I am pretty sure that it is, so that’s one all. A draw, if you like.

        I am not forgetting the surface 288 K, any more than I am forgetting the surface 1000 K, or the surface 300 K. You get my drift, I’m sure. Now the Sun was unable to stop that surface cooling to 1000 K, 300 K, or 288 K. As a rough calculation, the Sun can maintain a surface temperature of around 255 K. It’s still above that.

        Another quick calculation based on measured heat flux (rough, I know), shows a surface temperature of around 40 K without insolation. It seems that the Earth is losing heat, overall, at a rate equivalent to cooling of a few millionths of a K per year. Currently immeasurable, I believe, but calculated by geophysicists based on sound experimental science. The exact amount is subject to debate between real scientists.

        The atmosphere has a smallish insulating effect – in both directions of course. Its effect is amply demonstrated by a comparison of surface temperatures (after equal exposure times) on the Moon and the Earth.

        Unfortunately, Warmists bandy the term “radiative physics ” around in an effort to sound “sciencey”. They have no more clue than when they talk about “forcings”, or “radiative equilibrium”, or “back radiation”.

        All speculation, based on the bizarre notion that the future is an extension of the past. All you have to is adjust the past, and, eh! voilà!, the future emerges. Complete rubbish, of course. No science in evidence.

        Thanks for the support.

        Cheers.

      • That is exactly what I am talking about, Mike. You are driving the warmistas crazy with your discombobulations of their theory. And pointing out the trivial fact that the earth was really hot 4 billion years ago is a stunner. They will never be able to figure out why that is supposed to be relevant. You are undefeatable, Mike. Keep up the good work. That’s one of the reasons I like Aussies; hard workers.

      • Don Monfort,

        You wrote –

        “That is exactly what I am talking about, Mike. You are driving the warmistas crazy with your discombobulations of their theory.”

        I haven’t got the faintest idea what you are talking about. They don’t seem to have a clearly expressed theory that can be tested by experiment. No science at all. Just some strident nonsense about CO2, or emissions, or pollution, or how to stop the climate changing, or maybe we’ll all drown due to not grovelling enough . . .

        Maybe you know what it’s all about. Seems like some sort of bizarre delusional cult belief, to me.

        As to discombobulations, I presume you mean that I am upsetting their non existent theory. I am the discombobulated one, as there doesn’t seem to be a consistency amongst the various hypotheses put forward by different individual Warmists

        From the UK Met Office, in a paper titled “The recent pause in global warming (2): What are the potential causes?” –

        “The Earth’s temperature is controlled, fundamentally, by the balance between the solar energy absorbed by the planet and the thermal energy that it loses, which in itself depends on the temperature of the planet. The case for global warming rests on the greater trapping of thermal energy by increasing greenhouse gas concentrations within the Earth system . . . ”

        Trapping energy? Doesn’t the darned stuff cool down at night? Or do greenhouse gases just keep getting hotter and hotter?

        At least they acknowledge that something appears a little odd!

        Or you could try Dr Roy Spencer – Global warming 101 –

        “Every scientific theory involves assumptions. Global warming theory starts with the assumption that the Earth naturally maintains a constant average temperature, which is the result of a balance between (1) the amount of sunlight the Earth absorbs, and (2) the amount of emitted infrared (“IR”) radiation that the Earth continuously emits to outer space. In other words, energy in equals energy out. Averaged over the whole planet for 1 year, those energy flows in and out of the climate system are estimated to be around 235 or 240 watts per square meter.”

        The assumption is flawed, of course. The Earth has demonstrably not maintained a constant average temperature, no matter how much the Warmist cultists try to deny four and a half billion years of trivial fact.

        So what is this wonderful Global Warming or Climate Change nonsense? Is it an hypothesis or a theory? Who first put it forward, and where is it expressed in a testable scientific fashion? Nowhere, of course! Of course, I could be wrong – maybe a committee has come up with a theory, such that the members can deny ever having supported, if it makes individuals appear somewhat retarded.

        A wonderful hypothesis! Additional CO2 in the atmosphere might have undesirable effects, except when it doesn’t! The U.K. Met office can then write a paper trying to find reasons why something that doesn’t exist doesn’t seem to be happening!

        Oh, frabjous joy!

        Cheers.

      • Stop clowning, Mike. This is a guest post.

      • You wrote –

        “Stop clowning, Mike. This is a guest post.”

        I trust you won’t take offence if I take no notice of your first sentence. In regard to the second, the guest poster asked a question. I believe I provided an answer, and threw in a few facts in support when others took issue with my response.

        If someone asks a question, it is possible they may get an answer they don’t agree particularly like. Neither the guest poster nor Professor Curry have expressed any particular indignation, so I guess I haven’t overstepped the bounds.

        Climatology still seems about as scientific as phrenology.

        Cheers.

    • stevenreincarnated

      “A coupled atmosphere-ocean-sea ice general circulation model (GCM) has four stable equilibria ranging from 0% to 100% ice cover, including a “Waterbelt” state with tropical sea ice. All four states are found at present-day insolation and greenhouse gas levels and with two idealized ocean basin configurations. ”

      http://onlinelibrary.wiley.com/doi/10.1002/2014JD022659/abstract

      According to this model you will have to understand ocean heat transport in order to determine how stable we are.

      • Multiple solutions doesn’t address stability. Each has its own perturbation system.

        You tend to wind up, of course, in a stable solution.

      • stevenreincarnated

        Multiple solutions based upon changing the same variable does speak to what makes a climate stable. You’d have to have an understanding of that variable to speak to the ability to perturb it.

      • stevenreincarnated: According to this model you will have to understand ocean heat transport in order to determine how stable we are.

        thank you for that link.

      • Multiple solutions based upon changing the same variable does speak to what makes a climate stable. You’d have to have an understanding of that variable to speak to the ability to perturb it.

        No, stability is just a linearization of the system around whatever solution point you need the stability of. You look at the eigenvalues.

        If course, you have to know enough about the system to do this, which we don’t. I use the converse in the thought experiment. Whatever the system is, it’s stable at the point we’re at. Adjust your modelling to reflect that, rather than trying to say it’s unstable because of the model.

    • Trouble is, in a chaotic system, you can have large changes which appear not to change anything; and also immeasurably small changes which give abrupt shifts.

      Unless you understand the system, …..

  23. Negative feedbacks.
    “We don’t know what we don’t know”, I like that quote.

  24. Climate sensitivity, according to the IPPC was in the range 1.5 to 4.5C/doubling of Atmospheric CO2 – and that was their first prediction, 20 years ago…..today, they have studied it much more and have come to the conclusion they were right all along!

    I’ll “take” the 1.5 figure. Makes me feel right. besides, as Dr Feynmann stated: it doen’t matter who stated the theory, if the empirical evidence is different, the theory must change. Empirical evidence is less than 1.5C, so I’ll take it as the high end of the actual range for CO2 forcing. Nothing to worry about.

    So, all this banter at the COP21 will not affect me, except if they screw up the world financial system — and they said they are making it better….so, I guess we are better off, no matter what they agree to.

  25. stevefitzpatrick

    Nic,
    It looks like the solid black line in the second graph is the historical temperature record versus historical cumulative emissions. Could you not feed the model you are using the historical emissions data and compare the resulting temperature hind cast to the historical temperature record on the same graph? Seems to me that how well the model hind casts temperatures is important, since that gives some indication of expected (future) variation from the projection, or if you prefer, some idea of the uncertainty of the projection.

    • stevefitzpatrick

      Nic,
      Sorry, I had not read your earlier explanation to Ken Rice (ATTP)…. the solid black line is your model output. But would it not still be informative to plot the historical temperatures against cumulative emissions?

      • stevefitzpatrick,
        Thanks. I’m not sure that showing the historical record would add much. It is so close to the temperature simulated by my model that they would be difficult to distinguish. Only in the 1880s is the decadal mean GMST simulated by it more than 0.1 K different from that per HadCRUT4. The very strong volcanism in the 1880s caused a smaller drop in GMST than simulated, there was a very strong El Nino and the AMO was near its peak, hence the larger difference with observed GMST in that decade.

        The graph does show the HadCRUT4 value for the 2000s, which is dead in line with my model’s simulation.

        BTW, I do actually say in the article “the black lines show simulation results up to 2000–09”, which ATTP also missed.

  26. The curve of CO2 based Radiative Forcing ( from RCP historical and NOAA GHG index ) does appear convex down, with a peak in 2007:

    Quite consistent with slowing and aging global population.

    • Over the past then thousand years, the orbit cycle has taken 40 W/m^2 from the north and added it to the south and that made no difference to temperature. Now GHG is going to make a big difference with .045 W/m^2.
      Orders of magnitude increase in CO2 will not produce a tiny fraction of the energy changes that already occurred and did nothing to the temperature bounds.

      • . Now GHG is going to make a big difference with .045 W/m^2.

        I should label better.

        The peak was: 0.045 W/m^2 per year, or 4.5W/m^2 per century.

        The incoming TOA insolation change of the glacials was in fact around 40 W/m^2, but not the net, and that was local, not global.

        The incoming solar during the ice ages was about constant, but the polar changes allowed for ice accumulation.

        The global change of ~ 4W/m^2 would seem to warm the earth.
        That warming does not mean great changes in circulation or ‘climate’.
        Earth’s annual orbit, spheroidal shape, orientation of land/ocean are largely what determine ‘climate’ and those things aren’t going to change.

      • Earth temperature is regulated by the water, in all of its states. Look at the data. it looks like the temperature inside a house with a thermostat. it warms until the thermostat turns on the cooling and then it cools until the thermostat turns off the cooling.
        http://popesclimatetheory.com/page83.html

        The Earth’s two thermostats are set at the temperature that polar oceans in their hemispherse freeze and thaw. The cooling results from the snowfall that is turned on and off. The ice is stored on land in Antarctic and Greenland and Mountain Glaciers and released into the oceans and on land. The ice release and ice extent are regulated. When there is enough ice, the oceans freeze and turn off the snowfall. When there is not enough ice, the oceans thaw and turn on the snowfall. The result is just like in a house. Cooling is turned on every time it is needed and it stays on as long as necessary to freeze the polar oceans.
        http://popesclimatetheory.com/page38.html
        increasing or decreasing the energy input to a hemisphere does nothing to change the temperature bounds. The upper bound is a little above where the oceans thaw and the lower bound is a little below where the oceans freeze.
        http://popesclimatetheory.com/page85.html

    • The methane curve on the RCP/NOAA graph does not agree with EPA’s graph, which shows a continual increase in atmospheric concentrations (and therefore cannot contribute to the RCP/NOAA decline in Total GHG forcing). Which is correct?

      • TE:

        If NOAA and EPA actually agree on methane, where did you get the sharply declining Total GHG curve attributed to RCP/NOAA?

      • They are consistent.

        The chart I posted above is of the annualized ten year trend in Radiative Forcing due to each constituent, not the concentration or trend in concentration.

        RF is given by:

        CO2 ΔF = αln(C/Co) α = 5.35
        CH4 ΔF = β(M½ – Mo½) – [f(M,No) – f(Mo,No)] β = 0.036
        N2O ΔF = ε(N½ – No½) – [f(Mo,N) – f(Mo,No)] ε = 0.12
        CFC-11 ΔF = λ(X – Xo) λ = 0.25
        CFC-12 ΔF = ω(X – Xo) ω = 0.32

        Emisisons – uptake -> accumulations -> annual radiative forcing change

        Since RF is close to the speed of light, and the major feedbacks are ‘fast’,
        RF change is a representation of AGW change ( excluding that which may be going into the oceans, but lost there for a long time, only to emerge more slowly when needed ).

        AGW is not going away anytime soon, but the rate of AGW certainly has slowed since its overall peak in 1979, and the rate of CO2 AGW indicates deceleration and appears to have peaked in 2007.

      • If NOAA and EPA actually agree on methane, where did you get the sharply declining Total GHG curve attributed to RCP/NOAA?

        There is a follow up that is in moderation which details the answer.

        But the plot I have is of RF ( which is what causes AGW ), not concentration.

        Also, the CFC is just for CFC-12, not all the trace gasses (because the RCP and NOAA don’t have a common trace gas column).

        So the peak total RF around 1979 occurred because RF from CO2, CFCs, and CH4 all peaked then. RF from CO2 resumed growth, at least until 2007, and RF from N2O appears to continue, but total increases in RF would appear to be slowing.

      • TE:

        But the plot I have is of RF ( which is what causes AGW ), not concentration.

        Since RF is dependent upon absolute concentrations (not trends or rate of increase) you must actually be plotting something other than absolute forcing.

        Above, you mention W/m2/year peaking before 2000 but since the forcing effect is additive I still don’t grasp why your curve declines sharply in the absence of a reduction in absolute concentrations.

      • I still don’t grasp why your curve declines sharply in the absence of a reduction in absolute concentrations.
        ???

        If absolute concentrations were constant, what would the rate of change be?

      • TE:

        Thanks for the responses.

    • Also, wrt to the RF chart, China was awarded MFN ( Most Favored Nation trading status ) in December of 2001. But now, China’s economy is more efficient (robots) but also slowing.

      How many more China’s can there be? Given the population and switch from excluded to included in the global economy, I believe the increase from 2001 to present will not be repeated.

    • Turbulent Eddie: The curve of CO2 based Radiative Forcing ( from RCP historical and NOAA GHG index ) does appear convex down, with a peak in 2007:

      How is that known, back to 1900?

  27. Pingback: These items caught my eye – 1 December 2015 | grumpydenier

  28. Again is the GHG effect a result of the climate or the cause? I say the result. This is why the climate sensitivity to CO2 is not very relevant it should be asked the other way around which is how sensitive is CO2 to the climate.

  29. THE SCAM OF AGW WILL MEET IT’S DESTINY WITHIN THE NEXT FEW YEARS AND THIS SHOULD PUT AN END TO THIS ONCE AND FOR ALL.

    This is why I am not commenting to much because everything has been discussed over and over and over again. No one is going to change their mind for now. Now is the time to wait and see the test will be coming, talk now is just talk let us see what this test says. I expect to be proven correct.

    The test time is now and if prolonged minimum solar conditions become established (which I think is happening now) the climate test will be in play, and the fools at the climate summit knowing a prolonged minimum solar condition was likely should have taken the wait and see approach instead.

    Then again it is agenda driven not science driven.

    Below are the thoughts I conveyed to Joe Bastardi about how I view the situation.

    The climate summit is stupidity to it’s highest degree the blind leading the blind. I wish I could address the fools and show them why they are out if it and are clueless when it comes to the climate.

    WHAT A WASTE OF TIME !!

    Some points I would bring out and hammer if I were there.

    The way I see it the Test is on and those who think AGW IS real are going to be very disappointed and this disappointment will be realized before this decade is out IF my low average value solar parameters are achieved and have some staying power. I think they will be achieved and then we will see which side is correct once and for all.

    In the end it will depend on the degree of magnitude change of solar parameters and the duration of that change.

    I think if certain low average value solar parameters are met they will bring a cooling to climate due to weakening solar conditions but more importantly the associated secondary effects associated with a prolonged minimum condition.

    If for example intense volcanic eruptions occur in response to prolonged solar minimum conditions which they have in the past according to the data global temperatures will decline, despite the ocean heat content which will by the way eventually decline.

    We may have more EL Nino’s when the sun is quiet? That is only when the sun is in a steady rhythmic cycle and does not apply to prolonged minimum solar conditions. Even so if El Nino’s are to occur they will be superimposed upon sea surface temperatures in general which will be on the decline.

    Another factor which I think has to be watched is what is happening with Antarctica. The S. Ocean is way below normal in temperature and that could be one of those factors which is dismissed to create a climate impact. It is always the factors that are dismissed that I focus on.

    Then the atmospheric circulation pattern as we know can change the distribution of global temperatures in way that does not necessarily bring the global world wide temperatures down as a whole but effects the distribution of where the cold global temperatures are, which could create global cooling where it counts, the mid to high latitudes while leaving lower latitudes not much changed which would result in your point of view about the oceans holding up temperatures and the global cooling point of view that prolonged minimum solar conditions create a trend toward Ice Age conditions if not by cooling the globe all that much as a whole but rather on a regional basis for phase 1. This later progresses if prolonged minimum solar conditions persist.

    I think these are some of the things that have to be watched.

    In addition the globe has been in a cooling trend since the Holocene Optimum some 8000 years ago punctuated by spikes of warmth and I think Milankovitch Cycles , the Geo Magnetic Field with solar activity superimposed upon those two factors explain it quite well. This current warm spell is just one of those spikes in temperature in an overall cooling trend in my opinion post the Holocene Optimum.

    I want to see how high the temperatures spikes are with this El Nino and as you said how low it gets post this El Nino. My feeling is the spike will not be as high and the cooling post this El Nino will be greater. I think the cooling trend will be established before this decade ends and the unknown is climatic thresholds which are and must be out there because if one looks at the historical climatic record often times the climate goes along changing gradually then all of a sudden it changes in a step like fashion into another climate regime. That aspect seems to be being overlooked everyone seems to keep assuming the climate changes in a gradual fashion when past history shows us this is not the case and I think if the proper phasing of items that control the climate are achieved and the duration of time is long enough along with the degree of magnitude change that thresholds could be reached once again. I am not saying that will happen but if prolonged minimum solar conditions are achieve and are severe enough in magnitude and duration of time that possibility has to be considered.

  30. I am surprised, every day, at how many people waste time over man-made CO2 sensitivity and do not study anything else.

    Man-made CO2 did not cause the other warm periods during the last ten thousand years and there is no data that indicates this warm period is progressing any different. It is a natural cycle and we did not cause it. Whatever caused the previous warm cycles has not stopped. Temperature during the past ten thousand years was not a hockey stick. Only climate model output can create hockey sticks. The hockey stick was proven to be wrong. That does prove the models are wrong.

    • I believe you are correct that CO2 has become a distraction.

      But the calculable effect of CO2 on emission to space is global for just about every profile of atmosphere we observe. It does beg the question of if there is to be no effect from CO2, just how, exactly, the influence of CO2 would be reversed?

      There are possible reactions ( changes in lapse rates, changes in clouds ), but I don’t find any of them likely to be the result instead of warming.

      Now, temperature is just one aspect of climate, and global temperature rise also doesn’t seem to be that important a factor to climate as a whole ( seasons, precipitation, et. al. ).

      But I can’t see a compelling reason that the warming effect of CO2 should be reversed.

    • As with all guest posts, please keep your comments relevant and civil.

  31. Mosher is as funny as a dead baby’s doll.

  32. I’m on her blog mailing list. Thanks.

    Ian

  33. As an ignorant layman, am I to understand that the proof of a correlation of temp to CO2 is a period from the mid 1970’s onward? That the rise in temp for the first half of the 20th century was not due to CO2, but the rise of temp in the second half of the century was due to CO2?

    Is there a special “signature” in the data of the latter part of the century that distinguishes it from other temp rises in Earth’s climate history? Is it in dispute that in the past temps have risen and fallen with no apparent connection to CO2 levels?

    This is like someone asking me to believe that certain tree rings are a good proxy for temp some of the time and not others and I should just take their word for it.

    I have been dragged into this debate because it is now political and I vote. As I interpret the Earth’s climate record, the only conclusion I can reach for now is that sensitivity of temp to CO2 is zero.

    The sensitivity issue only seems to exist in theory and computer models and not reality. Is saying that the sensitivity is lower than we thought just a way to save face without admitting it is zero?

  34. So, global warming into the future is predicted to be practically negligible. Got it.

  35. Empirically, global warming alarmism is irrational but nevertheless real although grounded only in theory.

  36. I understand that Mosh has had an epiphany. He now talks in tongues, but they can be decoded. I will make four statements.

    *I understand that he now believes that CO2 has no impact on temperatures

    *That he believes the observational historic record is very valuable

    *That CET is a very useful indicator of not just England, but for much of the NH and possibly has some merit as a global proxy.

    *He is really looking forward to reading my article about 13th Century English climate, which appears to manage to be cold and very stormy and very very wet .

    If he answers with the following phrase , or those words in any order, it means he agrees with the statements.

    ‘As with all guest posts, please keep your comments relevant and civil.’

    tonyb

  37. Speaking of the relationship of CO2 to global temperature, the latest CFSR anomaly trend for this century so far, through November, still shows a significant downward trend despite a recent sharp spike in the monthly estimates for October and November. This 15-year downward global temperature trend is in sharp contrast to the continuing upward trend in CO2 levels.

    More details here:
    https://oz4caster.wordpress.com/

    • MSU trends for the same period are similar, which may be why CFS converges so.

      But 15 years may still be too brief a period.
      Wake me if the 20 year trends are similar.

  38. Wagathon said ” Empirically, global warming alarmism is irrational but nevertheless real although grounded only in theory”.

    It wouldn’t be irrational if there was some experimental or observational evidence to support the theory.

    The creation of the alarm however was not irrational if done for a political or social objective.

  39. Dont forget the RCP8.5 methane wasn’t really estimated, it was forced in to try to increase the forcing to 8.5 watts per m2.

    • I am hoping it is David springer pretending to be mosh, and not mosh doing a pale imitation of the person he used to be

      Tonyb

      • Mosher is being very well behaved today, Tony. He likes and respects Nic. As do all of us, except for kenny and his crew.

      • Steven Mosher

        Don gets it.

      • If it is you why not actually contribute?

        tonyb

      • Don Don,
        I don’t dislike or not respect Nic Lewis. I just expect better. Promoting your own work, while ignoring – or dismissing – that of others, is not the sign of an objective, unbiased researcher.

      • ATTP

        In what way is NIc ignoring or dismissing the work of others?

        If he was doing so, that would surely be another good reason for Mosh to participate properly because, presumably, as a result of his knowledge, he can add some useful additional perspectives to Nic’s paper?

        Tonyb

      • You are harder to read than the average bear, Steven. But I have been watching you for years. My training and experience in hunting bears and catching some alive to persuade them to point out where their friends live, gives me an insight into the thinking of bears that most denizens lack. If you want the untrained and inexperienced denizens to get it, you could be less cryptic. But you know that.

      • I call BS on kenny. You hate skeptics. Get yourself checked out. Where is your little sidekick, willy? We hope he’s OK and his spotty haunting of this blog of late is not due to poor health.

      • Don Don,
        Willard’s around and I think he has even commented on this post. I’m pretty sure he thinks I’m his sidekick, though :-)

      • I haven’t seen a willy comment, kenny. I could have missed a couple, but typically when willy is haunting you will see several of his gaudy gems in the recent comments. Now I am really getting worried about the little fella. If he is here, his haunting is very weak and a sign he is fading out. Una phantasma desaparecido. Pobrecito willy.

      • Don

        If willard’s presence is only very faint could he be the guest ghost that mosh has been going on about all thread?

        Tonyb

      • attp, “Promoting your own work, while ignoring – or dismissing – that of others, is not the sign of an objective, unbiased researcher.”

        It does create a bit of a competitive atmosphere which some find stimulating. Kinda leaps past that academic inertia situation.

      • “If it is you why not actually contribute?”

        I am.

      • Tonyb,

        You diminish yourself. Mosher is a non-entity, other than providing Judith with some useful graphics. On the other hand you do some really interesting and maybe useful stuff.

      • I think Mosh’s account has been hacked.

    • Stevie, why isn’t the rate of Globul Warmings accelerating like the models forecast ?

  40. Nic Lewis, thank you for the essay.

  41. In response to Nic Lewis’ comment to me of December 1, 2015 at 5:39 am:
    Thank you for changing GtC to TtC in several places in your lead post.

    You wrote “the transient climate response to cumulative carbon emissions (TCRE) – is 2.4°C/TtC at a 2°C rise from 1870. That is for RCP8.5, …”

    You apparently go that by taking the slope of a 2°C rise from 1879 divided by the RCP8.5 cumulative CO2 emissions of 830 GtC. But that is not a TCRE because the numerator, 2°C rise, is from cumulative CO2 + other GHE, while the denominator is only of cumulative CO2 emissions. You need to compare the 2°C rise to the cumulative CO2 + other GHE expressed in GtC, which is not the horiz axis.

    You wrote, “If one adjusts the CMIP5 RCP6.0 projection for the decade in which it just passes a 2°C increase in GMST, by removing warming corresponding to the non-CO2 element of RCP6.0 total forcing, the TCRE reduces to just over 2.0°C/GtC.” where you meant 2.0°C/TtC.

    The TCR is defined by a 1%/yr increase in only CO2, keeping other GHG constant. But the TCRE is defined by increasing CO2 AND other GHG. The temperature increase due to a TtC of methane is different from a TtC of CO2.

    Late last night the top scale of SPM.10 looked the same as the bottom scale, but now after a good night sleep, the scales are different, so you are correct that the units of the top scale are correct.

    • Ken,
      You say “But the TCRE is defined by increasing CO2 AND other GHG.”

      That’s not correct. IPCC AR5 defines TCRE, admittedly not very precisely, as: “The transient global average surface temperature change per unit cumulated CO2 emissions, usually 1000 PgC.”
      Other GHG gases do not come into TCRE. So removing the effect of all non-CO2 forcings on the GMST change, which my adjustment is intended to achieve, seems correct to me.

  42. Thanks for the essay Nic.
    ‘Past warming in CMIP5 models has been reduced by unrealistically large negative aerosol forcing – on average even stronger than per RCP estimates, which in turn exceed the AR5 best estimate’

    Have you considered running a simulation of a model with the ‘generally accepted’ water vapor and cloud feedbacks (ECS >3) but with the new aerosol forcing estimates? I understand it’s impossible to actually run the 90 or so models (or even one) on your home computer, but perhaps you can make some simplified ‘CMIP5-like’ model and see what comes out.

    This would show that the ‘match’ between models and temps is largely spurious. It wouldn’t invalidate them altogether, but it would show how unrealistic their feedbacks are. (Though my guess is that when the modelers finally adopt a lower aerosol forcing, rather than reducing feedbacks to match temps they’ll find something else to ’cause’ this negative forcing).

  43. albertozaragozacomendadorgmailcom,
    Your suggestion would show that, when using reduced aerosol forcing, the majority of CMIP5 models over-predicted past GMST rise. One could approximate the results by taking some mixture of the historical simulations, which have all forcings, the historicalGHG simulations and the historicalNat forcings, which only have the GHG or natural forcings respectively.

    However, some CMIP models do have low aerosol forcing. Several have lower than per AR5, as they deliberately do not include any indirect aerosol forcing, the largest and most questionable component of aerosol forcing in the majority of CMIP5 models. Some of the low aerosol forcing CMIP5 models overpredict past warming. However, others do not. That is mainly because they have low TCRs, either due to high ocean heat uptake, or to strongly time dependent effective climate sensitivity, or some combination of (possibly unknown) reasons.

  44. Thanks. By indirect do you mean effects of aerosols on clouds?

  45. Sorry Nic, I should have double checked the definition of TCRE.

  46. Since this question came up, just pointing to Nick’s post Why is cumulative CO2 Airborne Fraction nearly constant?”

    • stevefitzpatrick

      Hi Carrick,

      If you apply a 4 year boxcar filter to the Mauna Loa CO2 rate of increase, the influence of ENSO on atmospheric CO2, which is significant, is nearly eliminated (because ENSO is usually near 4 years for a ‘cycle’). This makes the underlying trend much more clear; the year-on-year increase grows, except for the 3 years following Pinatubo, but at a rate that is a little less than the year-on-year increase in emissions. My guess is that the airborne fraction is actually decreasing. That may not continue indefinitely, but it sure seems to be decreasing a bit right now.

      • Steve—I think you are right that the airborne fraction is currently decreasing. I think Nick agrees that there isn’t any evidence for an increase in airborne fraction either.

  47. Berényi Péter

    The multi-model mean and range simulated by CMIP5 models, forced by a CO2 increase of 1% per year (1% per year CO2 simulations), is given by the thin black line and grey area.

    OMG. This 1% per year meme is pervasive.

    In fact during the last 56 years, between 1959 and 2014 average annual increase of atmospheric CO2 concentration was 0.429% per annum, as measured at Mauna Loa.

    The difference is not negligible. At a nominal rate of 1% it takes 70 years to double the concentration, while at the actual rate it takes 162 years.

    70 years from now is 2085, while 162 years from now is 2177. Even the 0.43% per year rate of increase can’t be sustained for that long, because there is simply not enough cheap carbon based chemical fuel available.

    Therefore we shall be forced to switch to nuclear power, which is abundant indeed. One ton of ordinary granite, the default stuff continents are made of contains as much retrievable energy, as 50 tons of coal (+ 166 tons of atmospheric oxygen). The sun is going to turn into a red giant sooner than we’ll run out of this resource, because mass of continents is just huge.

    The technology is not new, it was available 50 years ago. With modern stuff we can certainly do even better than that.

    • stevefitzpatrick

      Yes, 1% per year is way higher than reality, which is currently about 0.6% per year. This means that all GHG driven warming to date has to be at a rate somewhat greater than the TCR, since the system has had extra time to respond. Warming to date represents a value somewhere between TCR and ECS.

    • Berenyi,

      Interesting post. Much can happen in 125 years. Burning whale light was replaced by Kerosine. Who’d a thunk? Anyway, I suppose the whales we’re happy. Who knows what will come along in 125 years? I don’t think anyone predicted the iPhone in the 1890s

      • Not tall tales, but time tells.

      • Fossil fuel did save the whales and it has saved countless humans.
        Think about New York City trying to use horses for horsepower rather that fossil fuel. Coal generates the most energy we use, coal is still king, coal can be used in power plants that remove the bad stuff. CO2 is good stuff and more is better. Antarctic is gaining ice and not adding to sea level. Temperature is not rising out of bounds. Life is good.

  48. How sensitive is global temperature to cumulative CO2 emissions?

    That is actually the wrong question in regards to government policy. China is right.

    The more correct question, is where will the climate change more (negatively and positively) as a result of increasing CO2 emissions and what is the expected net result.

    Warming does not necessarily mean a negative change in the climate. How is the relative climate in a specific area being measured as getting better or worse? Some areas benefit as the climate changes and some areas suffer harm. What are the metrics?

    Please, someone, anyone; show the data to justify that the world should believe the claims that there will be a net negative change in the climate. Let’s pick say 50 random locations and see how their data justifies their beliefs.

    • Either incredibly naive or incredibly deep, I need to think about this.

      What do you mean by China is right?

      • Deep is relative, but I think you will find that what I have written makes sense.

        China is advocating an approach that individual countries need to be able tailor their CO2 emissions based upon their individual situations. What if they think hey will have a better climate as a result of higher CO2 emissions? What if they think their citizens can benefit more if their limited resources are spent differently?

    • I like the idea of playing the “More CO2 is always better” Card. It won’t change temperature or sea level, but it will help every living thing that has green things that grow better, somewhere in their food chain. China does know that. India does know that. Russia does know that. Texas does know that.

    • Try to pick any location that is not better off when green things grow better while using less water. Pick it and prove it.

    • http://www.ipcc.ch/report/ar5/wg2/

      Example:
      http://www.ipcc.ch/pdf/assessment-report/ar5/wg2/WGIIAR5-Chap26_FINAL.pdf

      see figure 26-1

      of 14 different climate extremes

      4: no trend detected
      8: a trend detected, but NOT attributed to AGW
      2: trends detected and attributed to AGW

      A) predictions at not made at the “location” level
      B) at best it would appear that you can talk about regions.
      C) at the regional level, for the americas, roughly 15% of the
      selected extremes can be tied to AGW.

  49. Mark

    To avoid being “Mosherlike”or overly obtuse.

    Think about any individual location.

    What determines the conclusion that the climate there has been better or worse than what was expected based on the historical trend? Is it a single storm? Is it the annual average temperature?

    Answer- it depends upon the specific location and what changes there vs. the expected norms.

  50. Is this model actually posted anywhere for people to check. I didn’t see any code, formulas or parameter specifications anywhere, but maybe I’m just being blind?

  51. David Springer

    As of this writing 14% of the comments in this thread (39/279) belong to Ken Rice A.K.A. “and Then There’s Physics”.

    Over-posting troll lives up to its reputation.

    http://www.populartechnology.net/2015/01/who-is-and-then-theres-physics.html

    • Thanks. Funny and interesting. Why do some academics end up become trolls?

      • They stoop to trolling for various reasons, Peter. Prof. Eli Rabbetticus Halpernicus has a lot of time on his hands as his students go to sleep about 40 seconds after class starts so he’s got a lot of time to kill. And he’s nasty.

        Somebody else we know went into astrophysics because he thought that when he learned about how stars and planets are formed, he could actually create stars and planets. And get rich selling them. Disillusioned and bitter, he settled for teaching. Nobody takes astrophysics. What is the use of knowing how stars and planets are formed. So he had a lot of time on his hands. And he’s nasty.

    • David Springer: Over-posting troll lives up to its reputation.

      Funny cartoon.

      Since I have been disagreeing with aTTP, I think I ought to say that I do not regard him as a troll.

      • I agree. Like Jim D he stimulates very interesting and informative answers. It irritates me that some commentators respond to pettiness with more acrimony and derogatory remarks of their own.

        Personally I value people who can be skeptical can critical, because it sharpens the argument if it is sound, or exposes weaknesses if it isn’t.

        Nic seems to have a fairly solid argument, but I value others attempts at evaluating it.

  52. And then there’s data …

  53. Nic – will you be providing code and data, or did I miss it?

  54. The last lines of the lead post read:
    “When non-CO2 forcings per RCP6.0 are substituted for those per RCP8.5 (resulting in the green line), the TCRE based on RCP8.5 CO2 emissions is the same, 1.15°C/TtC, as for other scenarios. A better estimate of the simple ESM’s pure TCRE, with forcing only from CO2, is ~0.9°C/TtC.”

    By definition of TCRE, the “pure TCRE, with forcing only from CO2” is the TCRE. The 1.15 °C/TtC for the “scenarios” is not “pure” so it is not a TCRE as the temperature was forced by non-CO2 GHG.

    The TCRE of 0.9 °C/TtC includes two effects; the fraction of emissions that remains in the atmosphere, and the Transient Climate Response (TCR) to the CO2 that does remain in the atmosphere.

    Nic, please indicate the two components of the TCRE that corresponds to your calculated 0.9 °C per TtC of CO2 emissions.
    Does the corresponding TCR from your ESM agree with your calculated TCR from your Climate Audit post http://climateaudit.org/2015/03/19/the-implications-for-climate-sensitivity-of-bjorn-stevens-new-aerosol-forcing-paper/ where you determined the ECS and TCR best estimates are 1.45 °C and 1.21 °C, respectively?

    • Ken, in the absence of non-CO2 forcing the airborne fraction projected by my model in the second half of this century varies from about 40%-44% for RCP6.0 and RCP8.5 CO2 emission scenarios (the two with continuing growth in emissions), depending on scenario and date. The “pure” TCRE likewise varies; 0.9 K/TtC is an approximate value. Note that the airborne fraction is lower than with non-CO2 forcings included, as GMST change is smaller and hence carbon-climate feedbacks have less effect.

      As stated in my article, the TCR that my model is slightly over 1.35 K, and the ECS is ~1.70 K, being the values required to match observed historical GMST change and heat uptake (per HadCRUT4v4 and AR5 Box 3.1, Fig. 1). In the Climate Audit post you refer to I adjusted the 1750-2011 AR5 aerosol forcing best estimate to match the less negative estimate per Stevens 2015. Here, as stated in my article, I use non-CO2 forcings from the RCP dataset but modify their values to conform with AR5 estimates over 1765-2011. (The RCP dataset starts in 1765, but there was almost zero anthropogenic forcing change over 1750-65.) As I accordingly use the AR5 aerosol forcing estimate without adjustment to match Stevens 2015, the TCR and ECS required to match observed GMST and heat uptake changes are higher than those in my Climate Audit article.

  55. “How sensitive is global temperature to cumulative CO2 emissions”

    As I have repeatedly pointed out, the answer is that CO2 has NO climatic effect on global temperatures.

    All of the warming that has (and is) occurring is due to the removal of dimming anthropogenic SO2 aerosols from the atmosphere due to Clean Air efforts.

    From 1972 (when net global SO2 emissions clearly began to fall) to the present, projections of the expected anomalous average global warming, based
    solely upon the amount of reduction in SO2 emissions, are accurate to a tenth of a degree C. or (usually) less for any year for which net global SO2 emissions are known–when compared to NASA’s reported temperatures.

    With this nearly perfect agreement, there is simply no room for any additional warming due to CO2 to have occurred.

    Because SO2 removal is continuing, temperatures will continue to rise. There will be no cooling trend apart from La Ninas and volcanic eruptions, or possible changes in solar output.

    The only way to halt global warming is to halt further reductions in SO2 removal, or to devise mitigation strategies. Green energy projects, for example, that replace SO2 polluting sources will act to increase temps.

  56. Pingback: The Lukewarmer's Way

  57. richardswarthout

    Haven’t been driving much lately and put gasoline in my car today; first time in the last few weeks. I paid $1.76/gal. It was a pleasant shock, but as Rud warns in Blowing Smoke – the low prices aren’t here to stay. Fracking wells dry up very very fast, so expect $200/bbl oil by about 2022 and and a sharp increase in natural gas prices shortly thereafter. I’m building a new home within the next two years and it will probably have a geothermal system installed: don’t want to be the recipient of astronomical.heating and cooling bills when the fossil fuel price bubble blows.

    Richard

    • If you can forecast gas or oil prices with even modest success, than you can make a quick fortune. Nobody can forecast this, especially long term. Did anybody see the drop from $150 oil to $30 in a few month in 2008? Or The rise from $9 to 150 from 1998-2008? What about the collapse last year from $110 to $40 ?

      In 2005, with oil surging to $80, did anyone think a decade later it would be $40?

  58. Some thoughts on the airborne fraction, using these two graphs as reference:

    -It’s true that if one assumes stable or declining emissions, one can show a stable or increasing ‘real’ AF. For example, assuming 2GtC in 1960 (on top of the 2.5GtC from fossil fuels) drives down AF from 60% to 33%, i.e. lower than today.
    -But! Any land use emissions we add to today’s fossil fuels also lower AF. For example, if we assume just 1 additional GtC (half of the 1960 assumption) would reduce current AF from 43% to 39%.
    -Land use emissions are basically a guess, so any researcher can plug in his favorite estimate. I just wouldn’t put much weight on tthem.
    -Even so, the decline since 2000 (or since the 1990s, as the chart shows a 7-year mean) is pretty striking. This cannot be explained by land use emissions unless one makes ridiculous assumptions to square the numbers.

    So in this context Nic’s AF:
    ‘Ken, in the absence of non-CO2 forcing the airborne fraction projected by my model in the second half of this century varies from about 40%-44% for RCP6.0 and RCP8.5 CO2 emission scenarios (the two with continuing growth in emissions), depending on scenario and date’

    may actually be pessimistic, i.e. too high. (Not saying wrong! just saying there’s no reason to criticize it as too low)

    • ‘If one assumes stable or declining LAND USE emissions’

    • Alberto,
      As has already been pointed out, that figure for airborn fraction does not include anthropogenic land use emissions. These are thought have decreased since the 1960s, and hence the apparent decrease in airborne fraction is more likely to be a consequence of ignoring these emissions, than indicative of an actual decrease. This paper shows a small – but not statistically significant – increase over the same time period.

      • I’m assuming you’re writing from your phone or otherwise in a rush, as that’s what I discuss in the post above! ;)

      • That seems a pretty generous interpretation of what you said, but okay.

      • (previous attempt to post this comment apparently failed — WordPress seems particularly wonky these days)

        The paper cited by aTTP admits to large uncertainties in land use sources. (citations removed):

        …it is well known that uncertainty in fLUC is significant and propagates into the largest uncertainty in AF trend estimates. … The error on all fLUC estimates is large, typically ± 50 %.

        (fLUC = CO2 emissions from net land use change)

        In addition, the World Resources Institute does not agree that there has been a decline in deforestation’s contribution in recent years:

      • Ahh, I wasn’t clear in my first comment. It’s not the absolute magnitude of the land use emissions that have thought to have decreased since the 1960s, it’s the relative magnitude of the land use emissions (i.e., it is now thought to be a smaller fraction of the anthropogenic emissions today, than it was 60 years ago).

      • …now thought to be a smaller fraction of the anthropogenic emissions today, than it was 60 years ago).

        That certainly could be true, although the historical data can be sketchy. And WRI estimates that global annual tree cover losses (in millions of hectares per year) increased approximately 33% in the ten years before 2014.

        Coupled with huge error bars, it is hard to prove/disprove any specific claim for land use contributions.

      • Coupled with huge error bars, it is hard to prove/disprove any specific claim for land use contributions.

        Except that isn’t really the issue. The point is that arguing that the airborne fraction has decreased since the 1960s, using a graph that does not incude anthropogenic land-use emissions, is clearly wrong.

      • aTTP:

        The point is that arguing that the airborne fraction has decreased since the 1960s, using a graph that does not incude anthropogenic land-use emissions, is clearly wrong.

        If the graph you are referring to is the one shown earlier by TE as found in Figure 3 of Hansen, et al., (2013) it seems that Hansen did consider land use contribution explanations for the decline.
        http://iopscience.iop.org/article/10.1088/1748-9326/8/1/011006/pdf

        However, it is the dependence of the airborne fraction on fossil fuel emission rate that makes the post-2000 downturn of the airborne fraction particularly striking. The change of emission rate in 2000 from 1.5% yr-1 to 3.1% yr-1 (figure 1), other things being equal, would have caused a sharp increase of the airborne fraction (the simple reason being that a rapid source increase provides less time for carbon to be moved downward out of the ocean’s upper layers).

        A decrease in land use emissions during the past decade (Harris et al 2012) could contribute to the decreasing airborne fraction in figure 3, although Malhi (2010) presents evidence that tropical forest deforestation and regrowth are approximately in balance, within uncertainties. Land use change can be only a partial explanation for the decrease of the airborne fraction; something more than land use change seems to be occurring.

        We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks.

      • That still doesn’t change that trying to suggest that the airborne fraction has decreased, when the figure does not include all anthropogenic emissions, is not particularly strong, especially as there are other analyses that suggest the airborne fraction might have increased slightly.

      • And kenny murmurs:”there are other analyses that suggest the airborne fraction might have increased slightly.”

        Not particularly strong, kenny.

      • What you are saying Ken Rice would be considered by ATTP to be legalistic nitpicking.

      • @ attp –
        Yet you keep claiming “It seems that the airborne fraction is expected to increase so as to compensate for the logarithmic dependence on atmospheric CO2 concentration.” despite all evidence to the contrary.

        The further we displace the ratio of atmospheric CO2 to oceanic CO2 from equilibrium, the greater ocean uptake will be (and is arguably roughly proportional to displacement). It isn’t that hard of a concept.

        Maybe you should ask yourself why you are so insistent on having a belief contrary to evidence.

      • -1,
        Maybe I keep saying it because it is what most regard as what is likely to happen if we continue to increase our emissions. Consequently, the condescension in your response is rather surprising.

        This seems rather surprising, given what the IPCC says.

        The further we displace the ratio of atmospheric CO2 to oceanic CO2 from equilibrium, the greater ocean uptake will be (and is arguably roughly proportional to displacement). It isn’t that hard of a concept.

        Maybe you should ask yourself why you are so insistent on having a belief contrary to evidence.

        Maybe you should consider that it isn’t a belief and it isn’t contrary to the evidence.

      • “Consequently, the condescension in your response is rather surprising.”

        This is the comment section of an internet blog. You keep trying to read tone where there is none.

        “Maybe you should consider that it isn’t a belief and it isn’t contrary to the evidence.”

        Evidence generally suggests that the airborne fraction is constant or declining, as others have pointed out in these comments. In order to have an increasing airborne fraction, you would generally need emissions to increase at a higher than exponential rate (if uptake is roughly proportional to displacement from equilibrium). Emissions were increasing roughly exponentially during the 2nd half of the 20th century, but now emission growth is less than exponential (due to slowing population growth and increases in CO2 intensity) so if anything one should expect the airborne fraction to decline over the next half century.

      • -1,

        This is the comment section of an internet blog. You keep trying to read tone where there is none.

        Doesn’t mean it wasn’t condescending. Not that I’m complaining, mind you, my expectations are pretty low. I was more pointing out that condescendingly suggesting that someone is probably wrong when what you’re suggesting flies in the face of what most experts think, is more an indication of your hubris than anything else.

        Evidence generally suggests that the airborne fraction is constant or declining, as others have pointed out in these comments.

        The only evidence to a decreasing airborne fraction ignored an anthropogenic emission.

        Again, those who work on this think it will increase if we continue to increase our emissions, partly due to the reducing ability of the oceans to uptake CO2 as the temperature and concentrations go up, and partly due to a reduction in the ability of the biosphere to continue taking up the same fraction of our emissions. That’s why I happen to think that it might increase. It might not, but someone on a blog condescendingly suggesting that it probably won’t because it seems obvious to them, does little to convince me that it won’t.

      • “that someone is probably wrong when what you’re suggesting flies in the face of what most experts think”

        1. Who are all these self-declared experts you keep referring to?
        2. What matters is what the data and models suggest. Appeal to authority is not science.
        3. I think you suffer from a bad case of confirmation bias. Maybe people used to think that the airborne fraction will increase over time, but if the evidence suggests to the contrary, then why not change your position? This is similar to the question of ECS. Maybe a decade ago there was a ‘consensus’ that the best estimate of ECS was 3C, but since then more evidence has appeared. Some people take the new evidence into account and simply adjust their position. Others can’t get over their confirmation bias and refuse to change their minds.

        “Again, those who work on this think it will increase if we continue to increase our emissions”

        Maybe some people think that it will increase if emissions are increasing more than exponentially, but I doubt you will find any reasonable scientific model that suggests that increasing emissions implies increasing airborne fraction.

        “partly due to the reducing ability of the oceans to uptake CO2 as the temperature and concentrations go up, and partly due to a reduction in the ability of the biosphere to continue taking up the same fraction of our emissions.”

        Really? These are your major reasons? If you want a decent reason why airborne fraction might increase, you could go with the fact that different ocean layers have different response times, so the rate at which the Earth moves towards equilibrium divided by the displacement from equilibrium might be a decreasing function of time rather than roughly constant.

        With respect to the first ‘reason’, the oceans will tend towards equilibrium between atmospheric CO2 partial pressure and oceanic CO2 partial pressure (Henry’s law). By adding CO2 to the atmosphere, you are displacing the environment from equilibrium, so the system will move towards equilibrium by having the oceans uptake CO2. Yes, the warming due to increased CO2 will cause oceans to warm, which will make them less able uptake CO2. However, this will just affect the final equilibrium, which may cause reduced uptake, but won’t cause the airborne fraction to be increasing over time

        With respect to the second, why would the biosphere have decreasing ability to take up the same fraction of emissions? By a first order approximation, the rate at which the biosphere uptakes excess CO2 should be roughly proportional to displacement from equilibrium. Thus, the only way you could have increasing airborne fraction is by having CO2 emissions increase at a more than exponential rate.

        “because it seems obvious to them”

        I’ve also done some time series to demonstrate the effect. I think I posted some of the time series methodology and results on your blog once, but maybe your happiness engineer friend deleted them (I don’t remember).

      • @ attp –

        Okay, I’ll try to make it easier for you to understand what I mean by if emissions aren’t increasing more than exponentially then airborne fraction is unlikely to increase overtime.

        You can think of the earth as a system that tries to decay towards equilibrium between atmospheric CO2 and oceanic CO2, where the equilibrium atmospheric CO2 concentration may be affected by changes in global temperature and total anthropogenic emissions (both of which increase the equilibrium upwards).

        I need 2 main assumptions:
        1. The rate of CO2 uptake is roughly proportional to displacement from equilibrium. Many systems in physics respond linearly to displacement from equilibrium and you can think of this as a first order approximation. Increased atmospheric CO2 may cause more primary production and a greater difference between atmospheric and oceanic CO2 partial pressure, which should increase uptake.
        2. The oceanic CO2 partial pressure changes slowly over time relative to changes in atmospheric CO2 partial pressure. This is because the decay time towards equilibrium is relatively long (about 100 years).

        So lets say we start at equilibrium (pre-industrial times) and have emissions increase exponentially overtime. Say emissions are proportional to exp(tau*t), where tau is a constant and t is time.

        Total anthropogenic emissions are the integral of emissions. So are proportional to exp(tau*t)/tau, which is proportional to exp(tau*t).

        As oceanic CO2 partial pressure changes slowly over time, displacement from equilibrium will be roughly proportional to total anthropogenic emissions. Thus displacement from equilibrium is proportional to exp(tau*t).

        Finally, as the rate of CO2 uptake is roughly proportional to displacement, this means that the rate of CO2 uptake is roughly proportional to exp(tau*t).

        Thus the rate of CO2 uptake is proportional to anthropogenic emissions, which means that the airborne fraction is constant.

        So, in order to get an increasing fraction over time you need more than exponential growth rate in emissions. Emissions are growing less than exponentially, so if anything a falling airborne fraction should be expected.

      • -1,

        I’ll try to make it easier for you to understand what I mean by if emissions aren’t increasing more than exponentially then airborne fraction is unlikely to increase overtime.

        Oooh, thank you so much, my hero. Yes, I do understand what you’re saying. I’m pointing out something different, though. I’m not going to do your homework for you, but the general view is that if we continue to increase our emissions, the airborne fraction will go up. If you can access it, you could look at this paper, for example. You could read the IPCC reports, Chapter 6, for example

        Models show high agreement that 21st century cumulative airborne fraction will increase under rapidly increasing CO2 in RCP8.5 and decreases under the peak-and-decline RCP2.6 scenarios. The airborne fraction declines slightly under RCP4.5 and remains of similar magnitude in the RCP6.0 scenario.

        So, of course, it depends on our future emissions. So, yes, if we reduce our emissions, or follow a pathway where the increase is slow enough and peaks, then it won’t necessarily increase, but then I have been saying “if we continue to increase our emissions”. Nic’s model, for example, appears to suggest that it won’t increase even under an RCP8.5 pathway, which appears to be at odds with most other work.

      • “the general view is that if we continue to increase our emissions…

        So, of course, it depends on our future emissions. So, yes, if we reduce our emissions, or follow a pathway where the increase is slow enough and peaks, then it won’t necessarily increase, but then I have been saying “if we continue to increase our emissions”.”

        You just contradicted yourself.

        Increasing emissions slowly is still increasing emissions.
        Increasing emissions by 0.000000001% per year is still increasing emissions.
        Under those scenarios you are not going to get increasing airborne fraction.
        Therefore, increasing emissions does not imply increasing airborne fraction.

        So your claim ‘if we continue to increase our emissions then the airborne fraction will increase’ is false.

        “will increase under rapidly increasing CO2 in RCP8.5”

        RCP 8.5 has roughly exponential increases in emissions. Not to mention that there are all sorts of questionable assumptions that went into obtaining such a result (high ECS, unrealistic GHG emissions, etc.).

        “Nic’s model, for example, appears to suggest that it won’t increase even under an RCP8.5 pathway, which appears to be at odds with most other work.”

        Nic fits his model to empirical observations. The other results are based on models that don’t match empirical observations. I think it makes sense to put more weight on Nic’s result than those earlier results because of this.

      • You just contradicted yourself.

        Increasing emissions slowly is still increasing emissions.
        Increasing emissions by 0.000000001% per year is still increasing emissions.
        Under those scenarios you are not going to get increasing airborne fraction.
        Therefore, increasing emissions does not imply increasing airborne fraction.

        So your claim ‘if we continue to increase our emissions then the airborne fraction will increase’ is false.

        My goodness, what a wonderfully clever and insightful chap you are. On the other hand I did say “continue to increase”, not “increase and then peak”. I made the mistake of assuming that people might at least recognise that I was referring the kind of pathways we may follow in the future. I reaise that maybe I should be extremely careful what I say, but I do keep forgetting that I’m dealing with pedants who have no great interest in discssing this honestly, but simply want to beat their “it will all be fine, nothing bad can possibly happen” drums. Also, if you look at the RCP datasets here you might notice that even under RCP6 the airborne fraction increases. So, I will repeat (and slightly modify), my understanding is that under most of the higher emission pathways, the airborne fraction is expected to increase. I wait with baited breath to discover what bit of what I’ve said you can pedantically criticise.

      • He’s making a monkey of himself, in italics. Nice touch.

      • “On the other hand I did say “continue to increase””

        ‘continue to increase’ means that the derivative of emissions with respect to time remains positive. You get that with emissions increasing at 0.0000000000000000001 GtC per year, yet I highly doubt you would get increasing airborne fraction with that.

        “I made the mistake of assuming that people might at least recognise that I was referring the kind of pathways we may follow in the future.”

        If emissions increased by only 0.0000000000000000000001 GtC per year starting today, airborne fraction would decrease over time over the next several decades.

        “I reaise that maybe I should be extremely careful what I say”

        Please do so.

        “Also, if you look at the RCP datasets here you might notice that even under RCP6 the airborne fraction increases.”

        Airborne fraction increases from 2030 to 2080. During this time, the ratio of emissions to total emissions is roughly flat (and arguably increases from 2030-2070). So you have roughly exponential growth in emissions. This is what I mean by if you have less than exponential growth in emissions then you aren’t likely to get increasing airborne fraction. I will also point out that the ratio of emissions to total emissions declines at roughly the same rate from 1970 to 2030 and then suddenly breaks the trend around 2030 significantly. Why emissions would grow less than exponentially from 1970 to 2030 and then suddenly start growing exponentially from 2030-2080 even though population growth has slowed down significantly during this period and is arguably even in decline doesn’t make much sense to me.

        So this increasing airborne fraction is probably an artifact for whatever flawed economic model was used. Also you have things like using the high CMIP5 ECS.

        “under most of the higher emission pathways, the airborne fraction is expected to increase.”

        And I’ll point out that based on observations of emission trends and expectations about future population growth and economic development, CO2 emissions are likely to grow less than exponentially over the next century even under business as usual, which means that airborne fraction is unlikely going to be increasing over time.

        Pointing out that one can obtain an increasing airborne fraction using unrealistically high emission scenarios where emissions grow exponentially or more and using climate models with high climate sensitivity that don’t agree with empirical observations does not change this.

      • So, let’s get this right. You agree that the models that are used suggest that the airborne fraction increases along most of the higher emission pathways? This is really all I’ve been saying. You could always just think a little bit before doing the standard “aha, here’s something I can criticise”. Maybe the models are wrong, but that doesn’t change that those who work in this field suggest that the airborne fraction will probably increase along these pathways. So this entire discussion was simply a pedantic nitpick based on an increase of “0.0000001% per year” still becing an increase? Well done. Good job. You must be very proud.

      • Oh, and the reason we were discussing this is because Nic was using the same emission pathways.

      • “You agree that the models that are used suggest that the airborne fraction increases along most of the higher emission pathways?”

        I agree that if CO2 emissions increase more than exponentially then the airborne fraction will likely increase. However, I don’t think that such an emission scenario is likely.

        “that doesn’t change that those who work in this field suggest that the airborne fraction will probably increase along these pathways.”

        Key word is probably. How can they suggest that the airborne fraction will probably increase along these pathways if they are using models with improbably high climate sensitivity?

        “still becing an increase?”

        An increase is an increase. Your claim was false. Perhaps you should try to avoid false claims in the future.

      • Paleological evidense suggest that the airborn fraction trends isn’t likely to change any time soon. The large bio mass exposed by melting glacier (e.g. forests less than 1000yrs old in Alaska) and locked away in frozen tundra suggest that our ability to emit GHGs is unlikely to outpace sinks for very long.

        The very existence of fossil fuels suggest very large potential sinks.

      • …the models that are used suggest that the airborne fraction increases along most of the higher emission pathways? This is really all I’ve been saying.

        It just took aTTP 5000 words to say it…

    • “Hello, Times? COP 21 is faltering. Get us a sinking atoll or a bleached reef or some such thing. No forlorn polar bears, unless you’ve got nothing better. We can’t flog the Maldives any more, what with all those new airstrips and super-lux resorts. They’re such a bunch of sell-outs.”

    • ordvic and beth

      Sea levels in the Pacific Islands are fascinating in that there appears to be no correlation between island groups and there is such great variability by year and decade. Some rates have dropped dramatically in the last several years while others are quite high. Most stations across the globe have rates that can be explained by subsidence or glacial isostactic rebound etc, but these locations seem to have their own unique dynamics affecting their particular levels.

    • Another Darwin denialist amongst us.

      • No I was aware of this. Just because I post an article doesn’t mean I agree with it. I’m sure it is another complicated subject. I haven’t heard of any great sea rises so I wouldn’t know what was going on there. If the atoll formation works as described where does building on it fit in?

  59. Coral atolls essentially rise with sea level. Other factors
    are at play if an island is subsiding,
    http://wattsupwiththat.com/2010/01/27/floating-islands/

  60. stevenreincarnated

    Stop worrying about a few ppm of CO2 and sharpen your global warming causes cooling arguments.

    “The heat transport has decreased in recent years compared to values observed prior to 2009; the 5-year mean for the pentad 2009-2013 was 1.14 PW compared to 1.34 PW for the pentad 2004-2008.”

    https://www.rsmas.miami.edu/users/mocha/mocha_results.htm

    “We investigated the effect of increased ocean heat transports on climate in the Goddard Institute for Space Studies (GISS) general circulation model (GCM). The increases used were sufficient to melt all sea ice at high latitudes, and amounted to 15% on the global average. The resulting global climate is 2°C warmer, with temperature increases of some 20°C at high latitudes, and 1°C near the equator.”

    http://onlinelibrary.wiley.com/doi/10.1029/91JD00009/abstract

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  62. Nic Lewis, I like what you have been doing with regards to constraining climate model results with observed data. I judge our degree of confidence in climate model results and the uncertainty we might place on those results will be the major factor in any non-political approach to a reasonable policy on AGW and the only science related approach we have in determining the limits of future climate. I have not studied your post here sufficiently to comment at this point. Obviously the major points of contention and discussion with your approach would be the uncertainty of the observed data used.

    We should not sit back and look at the array of climate models and the outputs and be satisfied that somewhere in that range is a correct answer. The only method of validating models is with observed data. I have been analyzing the CMIP5 historical mean global climate model temperature series (1880-2005) in comparison with observed series using 5 categories which are: (1) temperature trend , (2) variance of the trend residuals (white and red noise), (3) variance of ARMA model (of the trend residuals) residuals or white noise, (4) ar1 coefficients of the ARMA models and (5) the ratio of S and N hemisphere temperature trends. What I have found is that attempts at putting statistical tests and significance on these comparisons of models versus observed is that none of the models is that no single model passed all the 5 category tests. Obvious also in such an analysis is the differences between models.

    Lots of good information in these exchanges that far outweighs the flotsam and jettisons that might sometimes appear to get in the way.

  63. Berényi Péter

    That picture (Figure SPM.10)

    First of all, a picture is not a proposition, it just is, no truth-value can be assigned to it. Therefore it does not belong to science. It can serve to illustrate a point by making it easier to comprehend some propositions, but it is an abysmal practice to replace propositions by images.

    That said, one can derive several propositions from an image.

    The black line is said to be “Historical”. Good.

    It shows 1063 Gt CO2 were emitted in 50 years between 1960 and 2010. That makes 290 GtC.

    In the same 50 years atmospheric CO2 concentration went up from 316.91 ppmv in 1960 to 389.85 ppmv in 2010 according to Mauna Loa Observatory, Hawaii. That means a 72.94 ppmv increase in 50 years.

    We can calculate the mass of this excess airborne fraction easily and it comes out as 56 Gt CO2. That is, 5.3% of CO2 emissions stayed in the atmosphere, while 94.7% went elsewhere. Now, that’s a curious proposition, I have never heard about it from authoritative sources.

    However, if true, it means residence time of excess CO2 in the atmosphere is short, which directly contradicts to claims, according to which it is extremely long. Sorry, in logic one can’t have it both ways.

    The other proposition I want to elaborate on is that temperature anomaly went up by 0.32 K in ten years between 2000 and 2010. If the picture is correct, this proposition has to be true.

    Unfortunately according to NOAA NCDC rate of warming between 2000 and 2010 was 0.13 K/decade, which is inconsistent with it being 0.32 K. Therefore the proposition derived from the picture is false, which means the image is incorrect.

    I am sure there are many more propositions hidden in Figure SPM.10, but it is quite enough to find a single false one to invalidate the entire thing. So at this point I lost interest.

    • 1063GtCO2 = 137ppm (assuming 7.75GtCO2 / ppm)

      So the airborne fraction is 53%

      • Berényi Péter

        You are right. I was off by an an order of magnitude.

      • Berényi Péter

        Well, we have better data than Figure SPM.10.

        see Fossil fuel and cement production emissions by fuel type
        Boden, TA, Marland, G and Andres, RJ 2013. Global, Regional, and National Fossil-Fuel CO2 Emissions, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., USA doi 10.3334/CDIAC/00001_V2013

        Airborne fraction is around 50% indeed, highly variable (between 26% in 1992 and 81% in 1972), but the general trend is decreasing, at a rate of 1.6% per decade.

        There must be a fast reservoir, with storage capacity roughly equal to that of the atmosphere and a much larger slow reservoir behind it.

        The general downward trend in airborne fraction gives information on coupling between these two reservoirs, which lets one calculate atmospheric lifetime of excess CO2.

      • Berenyi, I suspect a few major players are thawing of bio-mass and increased exposure to circulating air (increased thawing of tundra in NH), increased efficiency of the water cycle, increased transport of water from ocean to land and increased plant water efficiency making more water availible for biomass, and increasing biomass at the surface increasing uptake potential.

        Basically, some of the carbon from increased biological activity increases its resiliance and ability to take up carbon in future years. Kind of like a profitable company investing some of its profits in productive capital investments.

  64. That Hansen article has some terrifying quotes:
    http://iopscience.iop.org/article/10.1088/1748-9326/8/1/011006/pdf
    ‘We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks. One mechanism by which fossil fuel emissions increase carbon uptake is by fertilizing the biosphere via provision of nutrients essential for tissue building, especially nitrogen, which plays a critical role in controlling net primary productivity and is limited in many ecosystems (Gruber and Galloway 2008). Modeling (e.g., Thornton et al 2009) and field studies (Magnani et al 2007). confirm a major role of nitrogen deposition, working in concert with CO2 fertilization, in causing a large increase in net primary productivity of temperate and boreal forests’

    So more CO2 –> more plants –> more CO2 uptake. Pretty much the same story seen recently with the phytoplankton.

    • Alberto,

      Looks as though the Warmists have rediscovered Nature! I wonder if they’ll claim it as their intellectual property?

      Who know what else they may find, if they look around?

      Cheers.

  65. @ Nic Lewis-

    “Perhaps it would be better at this stage to use much simpler ESMs, with a few key parameters that can be selected so as to match observationally-based estimates of carbon-cycle and climate system behaviour.”

    I like this approach. Models should have free parameters that allow them to match empirical observations. And if the uncertainty of the empirical data is relatively high then it makes sense to use simpler models.

  66. There is absolutely no physics which can be used to deduce that water vapor and carbon dioxide cause the Earth’s surface to be warmer. Empirical evidence proves water vapor cools, and so too does all the carbon dioxide, but by less than 0.1 degree. Correct physics explains why. Surface temperatures are not determined by radiation, so radiation from carbon dioxide is irrelevant.

    This is continued in this comment.

    • If you had a model that is capable of projecting the average global temperature for any year 1975 – present with an accuracy of 0.1 deg. C. or less, would you agree that it correctly describes the cause of climate change?

      Such a model exists.

      • I would like to see what goes into such a model.
        If it is just a curve fit, that is not the same as a model.
        The actual data is not accurate to 0.1 C And after the model matched the data, then they do adjustments. Which version of the adjusted many times data did the model match?

      • Popesclimatetheory:

        No, it is not a curve fit. Actually, even simpler than that.

        In an attempt to understand why the rate of global warming slowed down around 2000, even though CO2 levels continued to rise, I wondered whether the warming was caused by something other than the accumulation of greenhouse gasses.

        The temperature recovery after the cooling caused by the SO2 injections into the atmosphere by the 1991 volcanic eruptions suggested that all of the anomalolus warming might also be due to the removal of anthropogenic SO2 aerosols.

        A “climate sensitivity” factor for the removal of SO2 aerosols was derived from the 1991 eruptions: 0.55 deg.C of temp. recovery divided by the 23 Megatonnes of SO2 injected gave approx. .02 deg. C. of temp. rise for each Megatonne of SO2 aerosols removed.

        To test my hypothesis, global tropospheric SO2 levels for the period 1975-2011 were obtained from published data, and, at various intervals, multiplied by .02 to determine whether the calculated amount of expected warming would match NASA’s avg. global Jan-Dec temp. for that year.

        For every year for which SO2 data was available, the match was within a tenth of a deg. C., or less (when occassional temporary natural variations due to El Nino’s, La Nina’s, and volcanic eruptions were accounted for).

        Now, all of the data that I have used has some uncertanity in it, and I must admit that I am somewhat amazed that it gives such accurate projections.

        As an example, global levels of SO2 emissions in 1975 were approx. 131.4 Megatonnes. By 2011, due to Clean Air efforts, they had dropped to 101 Megatonnes, a decrease of 30.4 Megatonnes. 30.4 x .02 = 0.608 deg. C. of expected anomalous warming.
        NASA’s recently revised value is 0.60 deg. C. (it was 0.61 deg. C.)

        Because there will be approx. 02 deg. C of temp. rise for each net Megatonne of reduction in global SO2 emissions, going forward, we can expect ever-increasing temperatures unless SO2 cleansing is halted.

        Unless you can find a fatal flaw in my model.

  67. For what it’s worth… independently these are my results:

    Take the 1958 atmospheric anomaly + 1959-2013 fossil fuel emissions and fit against 1959-2013 atmospheric anomaly (all in in GtC). Using an exponential decay model I found a very good fit, with tau ~ 58yrs ~ 40yr half life. Note that the land use emissions and land sinks were ignored.

    Observe that there is a deceleration in the acceleration of co2 emissions. For years 2014-2035, use a linear increase in emissions for 20 years based on the trend of the last 10 years and then assume constant rate 2036-2100. Use previously calculated fit to determine atmospheric anomaly. Results are cumulative emissions ~ 1500 GtC, atmospheric anomaly ~ 500 GtC. Very close to Nic’s results.

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