Guest post by Chip Knappenberger,
republished with permission from Master Resource (now on WUWT’s blogroll)
“A collection of research results have been published in the peer-reviewed scientific literature in recent months that buoys my hopes for a low-end climate sensitivity.”
One of the key pieces to the anthropogenic climate/environment change puzzle is the magnitude of the earth’s climate sensitivity—generally defined as the global average temperature change resulting from a doubling of the atmospheric concentration of carbon dioxide (CO2).
One of the reasons that the “climate change” issue is so contentious is that our understanding of climate sensitivity is still rather incomplete. But new research efforts are beginning to provide evidence suggesting that the current estimates of the climate sensitivity should be better constrained and adjusted downwards. Such results help bolster the case being made by “lukewarmers”—that climate change from anthropogenic fossil-fuel use will be moderate rather than extreme, and that an adaptive response may be more effective than attempts at mitigation.
In its Fourth Assessment Report (AR4), released in 2007, the Intergovernmental Panel on Climate Change (IPCC) provided this general guidance on the climate sensitivity:
[The equilibrium climate sensitivity] is likely to be in the range 2°C to 4.5°C with a best estimate of about 3°C, and is very unlikely to be less than 1.5°C. Values substantially higher than 4.5°C cannot be excluded, but agreement of models with observations is not as good for those values.
In IPCC parlance, “likely” means an expertly assessed likelihood of an outcome or result with greater than a 66% chance of occurrence. “Very unlikely” means less than a 10% change of occurrence.
Visually, the IPCC’s assessment of the climate sensitivity based on its interpretation of the extant literature at the time of its assessment is shown in Figure 1. The IPCC routinely includes studies which conclude that there is a greater than a 10% possibility that the true climate sensitivity exceeds 6°C and some which find that there is a greater than 5% possibility that it exceeds 10°C.
Fig 1. Climate sensitivity distributions retained (and in some cases recast) by the IPCC from their assessment of the literature. Note that the distributions fall off much more slowly towards the right, which indicates that the IPCC considers the possibilities of the climate sensitivity having a very large positive value (that is, a large degree of global temperature rise for a doubling of the atmospheric carbon dioxide concentration) to be not inconsequential (source: IPCC AR4).
If the true value of the climate sensitivity does turn out to exceed 6°C, then we will be in for what will probably turn out to be fairly disruptive climate change. Heck, even if the climate sensitivity lies much above 4.5°C, coming climate change will be substantial. I for one, would hope that it lies below 3°C, and actually turns out to be closer to 2°C.
A collection of research results have been published in the peer-reviewed scientific literature in recent months that buoys my hopes for a low-end climate sensitivity. Here are some salient quotes.
From “Climate Sensitivity Estimated from Temperature Reconstructions of the Last Glacial Maximum,” by Andreas Schmittner et al, 2011:
Assessing impacts of future anthropogenic carbon emissions is currently impeded by uncertainties in our knowledge of equilibrium climate sensitivity to atmospheric carbon dioxide doubling. Previous studies suggest 3 K as best estimate, 2–4.5 K as the 66% probability range, and non-zero probabilities for much higher values, the latter implying a small but significant chance of high-impact climate changes that would be difficult to avoid. Here, combining extensive sea and land surface temperature reconstructions from the Last Glacial Maximum with climate model simulations, we estimate a lower median (2.3 K) and reduced uncertainty (1.7–2.6 K 66% probability). Assuming paleoclimatic constraints apply to the future as predicted by our model, these results imply lower probability of imminent extreme climatic change than previously thought.
From “Bayesian estimation of climate sensitivity based on a simple climate model fitted to observations of hemispheric temperatures and global ocean heat content,” by Magne Aldrin et al., 2012:
The [climate sensitivity] mean is 2.0°C… which is lower than the IPCC estimate from the IPCC Fourth Assessment Report (IPCC, 2007), but this estimate increases if an extra forcing component is added, see the following text. The 95% credible interval (CI) ranges from 1.1°C to 4.3°C, whereas the 90% CI ranges from 1.2°C to 3.5°C.
From “A climate sensitivity estimate using Bayesian fusion of instrumental observations and an Earth Systems model,” by Roman Olson et al., 2012:
Current climate model projections are uncertain. This uncertainty is partly driven by the uncertainty in key model parameters such as climate sensitivity (CS)…The mode of [our] climate sensitivity estimate is 2.8°C, with the corresponding 95% credible interval ranging from 1.8 to 4.9°C.
The above papers examined the “equilibrium climate sensitivity”—that is the global temperature change that results when all climate systems reach equilibrium with the changes in climate forcing that result from a doubling of the atmospheric carbon dioxide content. The time it take to reach equilibrium depends largely on the response of the oceans (and how quickly heat is distributed with in them) and is not known with much certainty. Estimates of the time to reach equilibrium run from decades to centuries. Thus, the equilibrium climate sensitivity may not be the best measure of how much temperature (and related) change may occur over the nearer term, like say, over the course of the remainder of the 21st century.
A better estimate of that change is the “transient climate response”, or the amount of global temperature change that is manifest at the actual time that the atmospheric carbon dioxide is doubled (rather than waiting for the system to reach complete equilibrium). The transient climate response (TCR) is somewhat less than the equilibrium climate sensitivity.
Two recent papers examined the transient climate sensitivity. Again, here are salient quotes.
From “Improved constraints on 21st-century warming derived using 160 years of temperature observations,” by Nathan Gillett et al., 2012:
Our analysis also leads to a relatively low and tightly-constrained estimate of Transient Climate Response of 1.3–1.8°C, and relatively low projections of 21st-century warming… which is towards the lower end of the observationally constrained range assessed by [the IPCC AR4].
From “Probabilistic estimated of transient climate sensitivity subject to uncertainty in forcing and natural variability,” by Lauren Padilla et al., 2011:
For uncertainty assumptions best supported by global surface temperature data up to the present time, this paper finds a most likely present-day estimate of the transient climate sensitivity to be 1.6 K, with 90% con?dence the response will fall between 1.3 and 2.6K…
Now, by no means am I suggesting either that 1) the quotes above reflect all the intricacies of the respective papers, or 2) that these results are end all and be all on the topic. Neither, in fact, is true.
But, the excerpts above do reflect the general conclusion of each paper, as well as what makes them noteworthy. In fact, the IPCC in its Fifth Assessment Report (which is now under construction) will be terribly remiss (and misleading) if they present a Figure that looks anything like Figure 1 (above) from their Fourth Assessment Report.
In the intervening years, there has been substantial research into the probability distribution which contains the earth’s equilibrium climate sensitivity and the emerging bulk of evidence suggests that the IPCC’s “likely” range for the equilibrium climate sensitivity is much too large and that the possibility that the equilibrium climate sensitivity lies above 6°C is vanishingly small—if not entirely ruled out. Even the chance that it exceeds 4.5°C has been markedly reduced to being no more than about 5% (if not even less).
And when it comes to the “best estimate” of the “most likely” value of both the equilibrium climate sensitivity as well as the transient climate response, it is refreshing and encouraging to see new results from different research groups pointing to a lower number than that forwarded by the IPCC in its AR4.
It seems as we obtain more knowledge and understanding of reality, the specter of alarming climate change is driven further into the world of make believe.
References:
Aldrin, M., et al., 2012. Bayesian estimation of climate sensitivity based on a simple climate model fitted to observations oh hemispheric temperature and global ocean heat content. Environmetrics, doi:10.1002/env.2140.
Gillett, N.P., et al., 2012. Improved constraints on 21st-century warming derived using 160 years of temperature observations. Geophysical Research Letters, 39, L01704, doi:10.1029/2011GL050226.
Olson, R., et al., 2012. A climate sensitivity estimate using Bayesian fusion of instrumental observations and an Earth System model. Journal of Geophysical Research, 117, D04101, doi:10.1029/2011JD016620.
Padilla, L. E., G. K. Vallis, and C. W. Rowley, 2011. Probabilistic estimates of transient climate sensitivity subject to uncertainty in forcing and natural variability. Journal of Climate, 24, 5521-5537, doi:10.1175/2011JCL13989.1.
Schmittner, A., et al., 2011. Climate sensitivity estimated from temperature reconstructions of the Last Glacial Maximum, Science, 344, 1385-1388, DOI: 10.1126/science.1203513.
I still want someone to address the fact that all of the gases in the atmosphere qualify as greenhouse gases, per the definition as being IR active and “heat-trapping” (of course, this is a stupid definition as it defies thermodynamics, but hey that’s what the “climate scientists” make it).
If all of the gases interact with IR, and CO2 has one of the lesser IR spectra, the atmospheric interaction with IR becomes a constant and, thus, it is no surprise that they have trouble measuring sensitivity.
The satellite records of the IR flux show that the IR efflux has not changed in 40 years and may have even increased a little bit, which would make sense as CO2 replaces a bit of water vapor and makes the atmosphere LESS IR interactive.
When there is a small change in a bit player (CO2) and all the other gases are interactive, how can the change be detected? It is not.
Considering ‘adjustments’ to historical data records that exacerbate perceived warming, estimates of ‘forcing’ from the same can only be exaggerated.
The “no feedback” climate sensitivity is estimated as being about 1.2 C for a doubling of CO2, using the assumption that the “structure of the atmosphere does not change”. In other words, the estimate can be based by ONLY looking at radiation effects. This assumption has never been justified, ansd is almost certainly wrong. The lapse rate almost certainly changes as GHGs are added to the atmosphere.
Since this no-feedback climate sensitivity is the cornerstone of all IPCC estimations, it follows that all these estimations has no basis in physics.
Gah. When I hear “66%” described as being “likely” I want to puke. That is so far below any scientific standard that it is indistinguishable from coin-flipping. And the incestuous “expert opinion” process that generated it is EXACTLY the kind of nonsense that high-sigma falsification standards were designed to avoid.
And 90% is no better. Really. Even in the mushy social pseudo-sciences, where I took my degree, that’s looked on as very weak tea. In physics, it’s way down in speculation land.
As “what about Bob” would say – “baby steps”. At least we are moving in the right direction. GK
Good post thanks…
One more nail in the coffin of alarmist thinking.
There are 2 problematic assumptions in this article:
1. CO2 is bad. Tte 9 to 10 billion population in 2100 is going to need much more food grown on much less land and higher CO2 is one of the easier solutions.
2. CO2 rise will continue unabated. Doubled CO2 means 50% more plant growth – if we stop chopping down rainforest (and other land use changes) it will peak in the 400’s (ppm) if not it will peak in the 500’s. It is really difficult to drastically increase the rate of fossil fuel consumption. Over two-thirds of the CO2 rise is due to land-use changes and other non-fossil fuel sources.
We have 40% of “doubling” of CO2 already in the bank. given the logarithmic nature of CO2, that implies that close to 60% of the effect of “doubling” is already in the bank. That being the case:
1. If sensitivity was high, we would have already seen major temperature increases.
2. We have not seen major temperature increases.
Conclusion: Sensitivity is low.
Good things are happening, we need more of such research. Still a bit more than what I’d have hoped for but definitely not scary anymore.
What’s the climate sensitivity to CO2 if there is glaciation down past Wisconsin… again?
If there is about an 800 year lag between changes in temperature and changes in CO2, then CO2 concentration would continue to climb while people in the upper continental US and Canada are hightailing it to Mexico on their snowmobiles, eh?
I blame Soviets for inflating their temperature in wake of Czechoslovakia invasion:
See graphs 2 and 3 here:
http://www.vukcevic.talktalk.net/GT-AMO.htm
Let me add to my previous comment that there is no CO2 “signal” in the global temperature/time graph, which is discernable above the background noise. Which indicates that the climate sensitivity of CO2, when added from current levels, is indistinguishable from zero.
“Sensitivity” may be present in some imaginary equation, but it’s not present in the ACTUAL DATA. Therefore the setting of this parameter is utterly irrelevant. Might as well cheer that the Phlogiston Hamnicity seems to be lower than the Orgone Bassimation.
Poriwoggu says:
1. CO2 is bad. Tte 9 to 10 billion population in 2100 is going to need much more food grown on much less land and higher CO2 is one of the easier solutions.
In addition to that, if and when this interglacial ends, we are going to need elevated CO2 even more. During the most recent glaciations, CO2 levels fell to plant-starving levels. Now AGW adherents tell us that there will not be any new glaciation any time soon because of the elevated CO2. To me, that sounds like elevated CO2 levels is the perfect insurance against future food catastrophes: Either elevated CO2 stops the next glaciation, or if it doesn’t, it helps plants through it…
It’s less worse than we thought.
There are 2 problematic assumptions in this article:
1. CO2 is bad. Tte 9 to 10 billion population in 2100 is going to need much more food grown on much less land and higher CO2 is one of the easier solutions.
2. CO2 rise will continue unabated. Doubled CO2 means 50% more plant growth – if we stop chopping down rainforest (and other land use changes) it will peak in the 400′s (ppm) if not it will peak in the 500′s. It is really difficult to drastically increase the rate of fossil fuel consumption. Over two-thirds of the CO2 rise is due to land-use changes and other non-fossil fuel sources.
You know, people on this list say things like this, people on the CAGW say the opposite, nobody ever seems to give references. When I sought out references on higher CO_2 and plant growth, I discovered that (not unreasonably) the effect is rather marginal; plant growth is rate limited by many things, and doubling CO_2 isn’t going to e.g. double agricultural productivity. Furthermore, with modern farming there really isn’t any difficulty growing enough food for 9 to 10 billion people. The problem has always been that we do not use modern farming methods worldwide, and most world farming is constrained by a lack of energy and modern tools. Providing tractors and diesel and electricity and sowers and harvesters will have a far greater impact on productivity than the CO_2.
But I’m really interested in the latter claim. Over 2/3 of the CO_2 rise is due to land use changes and not fossil fuels? And you know this how, or from what study? I’m not asking in a critical way — I’m asking because I genuinely do not know the answer. Some fraction of our CO_2 anomaly comes from the warming of the ocean. Some of it comes from burning fossil fuels, where we can certainly tally up fuel used every year and CO_2 produced from the given consumption of fuel. Land use changes actually seem IMplausible as a significant factor to me offhand — a distant third. Things are complicated by the fact that the ocean is a dynamic source and sink, by the fact that volcanoes release CO_2, by the fact that e.g. unburned methane from e.g. the Gulf Oil Spill oxidizes to CO_2 (and water) and much more.
So please, if anybody has a really plausible, well-documented source for the currently enormously variable claims concerning anthropogenic and other CO_2, I’d love to see them.
rgb
Ever wonder why there are no zero or negative sensitivities shown on the plot? This is an example of confirmation bias…projecting our assumptions into the data. For every year there was a downtick of global temperature when CO2 rose, the plot should show correlation to an inverse relationship. It’s in the data, but it’s not in the plot. Interesting, eh?
The Fictive World of Rajendra Pachauri
Tony Thomas
http://www.quadrant.org.au/magazine/issue/2012/3/the-fictive-world-of-rajendra-pachauri
In 2005 the chair of the Intergovernmental Panel on Climate Change (IPCC), Rajendra Pachauri, flew to a Washington conference. He spent ninety minutes getting through the airport formalities. A chauffeur-driven car had been waiting outside, with the engine and air-conditioner running so that Pachauri would have a cool car to step into. Pachauri was indignant. “My God! Why did you do that?” he rebuked the driver. “You probably had the engine on for two hours. Was that really required?” He told North Carolina legislators three years later: “So that’s the kind of change in lifestyle that I’m talking about … which when put together will really make an enormous difference.”
—————————————–
I began this profile with Pachauri’s address to the North Carolina legislators and will end with it. First, he wrongly thought he was “off the record”. Second, he clearly set out to scare the legislators witless, with such forecasts as a 90 per cent drop in African crop harvests by 2100, along with security and peace issues with Africans heading out of Africa literally for greener pastures. To avert such perils, including “several metres” of sea-level rise, he said that the world need only give up one year’s GDP growth (3 per cent) by 2030, or 5.5 per cent of world GDP if we rashly delayed the emission targets to 2050.
Pachauri climaxed his address with a quote (probably taken from Al Gore’s book Earth in Balance) by native American Chief Seattle in 1854: “Man did not weave the web of life, he is merely a strand in it. Whatever he does to the web, he does to himself.” My b.s. detector beeped and sure enough, Chief Seattle’s eco-poetry is, in polite academic-speak, “inauthentic … an evolving work of fiction”.
I accept unreservedly that an increase in CO2 increases the amount of downward radiation and potentially increases global temperatures. I also accept unreservedly that there is the potential for such changes to induce positive feedback effects that increase temperatures further. However I have seen nothing that proves that these changes do not induce negative effects such as increased radiation into space and increased cloud albedo. Indeed, if I look at the paleo data with my control engineering hat on I would say that the data looks more like negative feedback than positive. So why are all the likely values for the sensitivity positive?
Thanks Chip Knappenberger for a good posting, but IMHO you do not go far enough in reducing the most probable climate sensitivity, which I think is closer to 1⁰C than the IPCC mean of 3⁰C.
You mention the excellent Schmittner [2011] paper, which I discussed in my WUWT posting CO2 Sensitivity is Multi-Modal – All bets are off.
The IPCC graph displayed at the head of your posting extends all the way out to sensitivities of 10⁰C, or higher. Schmittner proves to my satisfaction that any values greater than about 6⁰C would retrodict a “total snowball Earth” at the Last Glacial Maximum which contradicts clear evidence that the ice sheets did not extend equatorward beyond the middle of the USA or corresponding latitudes in Europe, Asia, South America, or Africa. Indeed, the tails of the IPCC graphs that extend beyond 5°C (or perhaps even 4°C) should approach zero probability.
The papers cited above average out somewhere between 1.5°C to 2°C, which is closer to the truth than the IPCC 3°C. I predict that further study will show the actual truth is 1°C or less, possibly as low as 0.5°C or even 0.25°C, which would be good news indeed.
Ira
good one, Polistra:
” Phlogiston Hamnicity seems to be lower than the Orgone Bassimation.”
that is a perspicacious summation.
Brian H says (March 19, 2012 at 7:42 am)
“Gah. When I hear “66%” described as being “likely” I want to puke. That is so far below any scientific standard that it is indistinguishable from coin-flipping.”
Quite right! In particle physics, 5-sigmas (repeatable) is required before you can say you have a valid signal in the noise. That’s 20 coin tosses in a row.
To make things worse, it’s GISS-adjusted noise. Puke away!
The current lack of warming indicates low sensitivity,
but even more so does the lack of cooling in the main CO2 band at 15 microns.
These are actual data, not theory.
Also, the theory should be 1 deg or below anyway,
when you look at the theoretical warming for 300-600 ppm rise
it’s only 0.66 K, about 1.2 F, not enough to be able to measure.
Truly, the catastrophe is entirely imaginary.
“One of the reasons that the “climate change” issue is so contentious is that our understanding of climate sensitivity is still rather incomplete.” To this layman, this looks like a satirical understatement out of a Monty Python skit. Also, thanks to others above for identifying problematic assumptions.
I’ll go with the author trying not to be unnecessarily contentious. Should science be trying to tweak the IPCC narrative when that narrative is so limited to the last 30 years of 2 billion and is proven to do a rather poor job of predicting the past and the present with its “rather incomplete” “understanding?” All I can see in the AGW case is retrofitting data to justify concentrating on only one variable. That’s not just rather incomplete, it’s structurally flawed at formation of the problem.
Meak, but serving to underline AGW weakness by trying to be meak and still finding low sensitivity.
“Jim Cripwell says:
March 19, 2012 at 7:35 am (Edit)
The “no feedback” climate sensitivity is estimated as being about 1.2 C for a doub Againling of CO2, using the assumption that the “structure of the atmosphere does not change”. In other words, the estimate can be based by ONLY looking at radiation effects. This assumption has never been justified, ansd is almost certainly wrong. The lapse rate almost certainly changes as GHGs are added to the atmosphere.
Since this no-feedback climate sensitivity is the cornerstone of all IPCC estimations, it follows that all these estimations has no basis in physics.
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you dont know what you are talking about
If you noticed nearly 1,000,000PPM of N2, O2 and Argon molecules had a temperature and did not radiate much in IR wavelengths, would you think an added CO2 molecule would heat or cool (or do nothing) to the Earth’s surface temperature?
Whatever is said or printed purporting to show the IPCC AR4 assessments are too high, you can be sure that step by step HadCru wil come to the rescue with new computations adding small amounts of recent warming here and there, such as the new HadCrut 4 ably assisted by Louise Gray of the Telegraph here in UK
http://www.telegraph.co.uk/earth/earthnews/9153473/Met-Office-World-warmed-even-more-in-last-ten-years-than-previously-thought-when-Arctic-data-added.html
and ably backed up by the usual suspects such as Dr Jones and Dr Stott.
“Between 1998 and 2010, temperatures rose by 0.11C, 0.04C more than previously estimated.
The new data set also shifts around the hottest years on record, so that the new temperature series, known as HadCRUT4, is more in line with other global records held by NASA and NOAA in the US. The American series had already added Arctic temperatures from extrapolated information.
Before it was thought the hottest years were 1998 followed by 2010, 2005, 2003 and 2002. The updated series puts 2010 as the hottest year on record followed by 2005, 1998, 2003 and 2006.”
So finally they managed to make 2010 warmer than 1998. I like the bit about “Arctic temperatures from extrapolated information”. Sounds like Dr Hansen is winning the argument within the “Team”.
Robert Brown,
Look at the levels of CO2 used in tomato greenhouses in The Netherlands, typically 1200 to 1500 ppm, and look at the yields.
Sorry I don’t have links.
Be careful here. Remember: the IPCC isn’t now, nor has it ever been, about “Global Warming”.
No matter what climate sensitivity is ultimately accepted as the most likely figure, the alarmists have already moved on from that as a talking point. They’ll still use it, but the mantra now is “extreme weather”, and every natural disaster and odd stretch of weather is being used as an example of how we’ve upset the delicate balance that used to protect us from harm.
Look at 2011. Global temperatures were down, but snowstorms, tornadoes, droughts and Hurricane Irene were all blamed on “climate change”. The actual mechanism isn’t described, since no one could point to additional heat in the atmosphere, but that hasn’t stopped scientists from providing quotes to the media saying that it’s all consistent with warnings.
They’re still hard at work, adjusting the past and fudging the present so that something shows up in the temperature record as different from earlier decades. Even while climate scientists privately acknowledge a plateau, there are alarmist blogs who are still saying that warming has continued and even accelerated, utilizing all of that uncertainty and the error bars that they would never discuss before.
So many peas under so many thimbles, and they’re desperately moving all of them. Climate sensitivity is a battle they’ll fight during El Nino years, but right now they’re perfectly content using weather.
Put the models into the regions where CO2 were high and rising and they fail miserably as the temperatures actually fell after these periods as one would expect. There is not just a low positive forcing there has to be a negative one or the relative stability we can be certain existed pre the human era could never have been possible.
When will any of the climate science fraternity be able to say this without being excluded and being forced to choose poverty or an adequate severance package with silence as the price?
Well, they are getting closer but as the earth has an inherently rather stable climate, the real feed-backs are probably negative thus the sensitivity is almost assuredly less than 1.2. Give em another ten years and those not corrupted by ideology will finally get the answer right. In the meantime… let’s get back to using coal (without CC&S), nuclear and natural gas for electricity, Roll back all of the inane EPA regulations (mercury and new particulates and sulfur that are forcing the shut down of our power plants and bankrupting the middle and lower class) while continue research on fusion energy for the future.
Robert Brown says:
March 19, 2012 at 8:40 am
Some fraction of our CO_2 anomaly comes from the warming of the ocean.
I do not agree with this. Over the last 15 years for example, the surface temperature of the ocean has not changed, but CO2 has gone up steadily. Furthermore, over the last 10 years, surface temperatures of the oceans have even gone down. See:
http://www.woodfortrees.org/plot/hadsst2gl/from:1997/plot/hadsst2gl/from:1997.08/trend/plot/hadsst2gl/from:2002.08/trend/plot/esrl-co2/from:1997/normalise
As well, see:
http://www.telegraph.co.uk/earth/earthnews/6538300/Climate-change-study-shows-Earth-is-still-absorbing-carbon-dioxide.html
One sentence in this site says: “According to the study, the Earth has continued to absorb more than half of the carbon dioxide pumped out by humans over the last 160 years.”
Since this post and comments have the attention of some of my most respected WUWT commenters and touches on the subject of feedbacks, please point me in an informative direction regarding two questions I have had for some time:
1. If warming from increased CO2 causes water vapor uptake which causes more warming etc. (a positive feedback loop), what natural process damps or limits the feedback so it doesn’t run away beyond the CAGWers generally accepted 3’K or so per doubling? Is it identified in their original hypothesis? Is it an arbitrary oops-induced tweak to the models to stabilize them? Is it an unanticipated but plausible prediction of the models that emerges from the interaction of model givens and variables?
2. I’ve seen this asked here many times but have not seen it answered: By what unique process do CAGWers believe is it only CO2-forced (or anthropogenic) warming that creates water vapor feedback? Would not natural warming from ANY source create water vapor positive feedback (thus making it a frequent and detectable/measurable phenomenon)? Is there plausibly a “tipping point” that is uniquely CO2-sensitive?
It seems to me that the plausibility of positive feedback and thus the C of CAGW hinges on (at least) these questions. Should not our war room have signs everywhere reading, “It’s the feedback, stupid!”?
I don’t want to hijack this post, so please just point me to the appropriate place to look to gain an understanding of both sides of the feedback issue. Thanks!
@Robert Brown says:
March 19, 2012 at 8:40 am
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Robert
Whilst I do not know the accuracy of the figures cited by Poriwoggu (says:March 19, 2012 at 7:59 am ), I did not consider the thrust of the points that he raised to be controversial, and I thought that they were in general well accepted.
According to WRI (World Resouces Institute) for the year 2000, CO2 emissions in 1,000mt units including change in land use were:
World: 31, 639,647.9. Of this, the emissions of the following countries are of note:
Dem Rep. of Congo (a non industrialised country) emitted some 318,942.1 which is broadly similar to France (an industrialised country) whose emissions were 358,734.5. France has low emissions (by Western Standards) because of its substantial use of nuclear.
The industrial power house of Europe, namely Germany, emitted some 857,954.3. This is broadly similar to Malaysia which emitted some 819,443.3. I consider that well illustrates how land use can have a similar impact to heavy industry.
Even Myanamar (not well known for its industrial might) emitted some 434,592. If one wanted to look at a non industrial farming country which is not undergoing significant land use change, New Zealand emitted some 36,226.3. I accept that that is not a fair comparison but it does highlight the adverse effect of land use change.
Indonesia emitted some 2,857,352.0 which is broadly the same as the whole of Europe combined (the UK is the 2nd largest European emitter with 549,930.1). Land use change is rife in Indonesia and its emissions far exceed that of Brazil (1,708,850.4) where they are trying to cut back on deforestation.
Of course, it is not simply deforestation that causes a substantial rise in emissions, it is slash and burn. Slash and burn accounts for a very significant part of human emitted CO2. Of course, there are natural forest fires which also add to the emissions.
As regards CO2 and plant growth, I have read a number of papers on this. Some suggest an increase of about 13% whilst others suggest more than 40%. Of course, other factors are at play such as temperature and sufficiency of water and other nutrients. I thought that it was well accepted that the planet is presently greening and this is due to the increased level of CO2. I therefore consider that the general thrust of point 1 to be correct.
Polistra has made an excellent point above, and I’d like to reiterate and expand upon it.
Climate Sensitivity (CS) is an inferred value, it’s not a fundamental physical law. Instead, it is our best estimate of the sum total effect of ALL the forcing and feedback mechanisms currently acting on the planet, stated as the combined effect they will have on temparture for a given increase in radiative forcing (i.e. 2xCO2) over a given time (long enough to allow the relevant feedback mechanisms to have an effect). But no matter how well we estimate the value of CS, it is only a valid estimate for the particular set of conditions that existed in the period being measured.
This study by Schmittner et al. attempts to quantify CS during the Last Glacial Maximum, and finds a low value. Other studies relying on data from other periods find higher values. These are not mutually exclusive findings because the climactic conditions were different for each study.
At the Last Glacial Maximum, a sizeable area of the northern hemisphere was covered by ice, which would certainly had an impact on many of the biological and physical processes that result in feedbacks. (e.g. fewer plants abosrbing less CO2, colder oceans abosrbing more CO2, less water vapour in the atmosphere, greater ice albedo effect, etc.)
It stands to reason that CS should be different at the depths of an ice age than during an interglacial, and also different at various points in between.
For the sake of argument, lets assume that we’re at or near the warm end of the planet’s range (average around 15C), and that the cold extreme, during an ice age is around 6 degrees cooler (on average around 9C).
My hypothesis would be that CS is low (1-2C / 2xCO2) at the extreme ranges of the earth’s temperature (cold ice ages and warm interglacials), but higher (as high as 4-5C/2xCO2) in the middle of the range (when the planet’s average temeparture is around 12C).
The result would be that if temperatures began to fall from present warm conditions, we’d move to a zone with higher CS, which would accelerating cooling and eventually lead to a tipping. Then as temperatures continued to fall, we’d move into a lower CS zone, until the net feedback was again negative.
However, if temperatures were to rise from here (say to around 17C), we’d move to a zone of even lower CS, resulting in even greater negative feedback, acting as a constraint to prevent further temperature increase.
End result… a system that flip-flops between two equilibrium states, one warm and one cold, but never moving beyond the upper and lower boundaries of that range. Kind of like what we’ve observed our planet doing with amazing regularity for the last few million years.
Due to the mentioned scientists in the sensitivity graph, e g Richard Lindzen’s and Roy Spencer’s prediction of about +0.5 C is almost impossible…
Climate sensitivity is a key component of the debate and one on which the warmists are particularly weak. This is why the warmists did not like the recent Spencer paper which suggested that net feedback could well be negative.
It is an inescapable fact that given the margin of error and the variability of noise (whatever the source of that variability be), one cannot discern a CO2 signal in the instrument temperature anomaly time series. The fact that such signal cannot be discerned strongly suggests that the sensitivity to CO2 cannot be particularly high.
It is important to emphasise that the claims for high sensitivity are not backed by any hard observational data and such observationaal data that exists points to a low sensitivity.
Have a look at the two plots on page 20 of the attached summary showing CO2 verses Hadcrut3 and CO2 verses GISS which demonstrate the point made above.
http://www.climate4you.com/Text/Climate4you_February_2012.pdf
“And 90% is no better. Really. Even in the mushy social pseudo-sciences, where I took my degree, that’s looked on as very weak tea. In physics, it’s way down in speculation land.”
As I said somewhere else, what’s the likelihood that people would have taken NASA seriously if they said they could predict the correct position of the moon for the Apollo moon landings with at least 90% confidence.
Jim Cripwell says:
March 19, 2012 at 7:35 am
The “no feedback” climate sensitivity is estimated as being about 1.2 C for a doubling of CO2, using the assumption that the “structure of the atmosphere does not change”.
==============================================
The whole thing about climate sensitivity of CO2 or the “greenhouse gasses” is based on the claim, that our planet is so pleasantly warm because the “greenhouse gasses” trap infra-red radiation and otherwise our planet would be 33 degrees Celsius colder.
If you take a closer look at the calculations, you might notice a primitive manipulation: in the process of the calculation and explanation the word “atmosphere” get simply replaced by the words “greenhouse gasses” and the conclusion is made about “greenhouse gasses” instead of atmosphere.
But regardless of this trick, the idea about “greenhouse gasses” warming our planet by trapping radiation was debunked long ago, back in 1909 by professor R.W.Wood, after the “father” of the “greenhouse” hypothesis Arrhenius published his book in 1908.
http://www.wmconnolley.org.uk/sci/wood_rw.1909.html
After that the “greenhouse” hypothesis died successfully and remained dead for about 70 years, until certain groups dug that corps out and created a “catastrophic CO2 warming” concept.
About Professor Wood: http://en.wikipedia.org/wiki/Robert_W._Wood
Chip says:
But new research efforts are beginning to provide evidence suggesting that the current estimates of the climate sensitivity should be better constrained and adjusted downwards. Such results help bolster the case being made by “lukewarmers”—that climate change from anthropogenic fossil-fuel use will be moderate rather than extreme, and that an adaptive response may be more effective than attempts at mitigation.
Henry says
Sorry man. There is no warming as a result of an increase in GHG’s
nor from more volcanic activity on earth
nor from man driving, flying, heating , cooling, boiling and burning stuff
because if there were, then the pattern of the observed warming should be exactly the opposite as what we are finding it.
http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming
vukcevic says:
March 19, 2012 at 8:20 am
I blame Soviets for inflating their temperature in wake of Czechoslovakia invasion:
See graphs 2 and 3 here:http://www.vukcevic.talktalk.net/GT-AMO.htm
Ok, vukcevic, this got my attention. Partially my fault. I was a kid in Prague in ’68. We played at being in the Czech Resistance and used to buy little lighter fuel gasoline capsules, pop them, spill them on the ground and light them. Once we sparked a small grass fire on a roadway median strip near a Soviet Tank…to smoke out the invader. The troops didn’t even notice, but we thought that was it for us and peeled off, spending then the next month or so hanging around at home, driving the folks nuts without them knowing that we were “hiding from the NKVD.” It was a warm spring and a hot summer, too.
But really,any reasons for the temp record jump just then?
Robert Brown [@3/19 – 8:28 a.m.
I have nothing to add regarding your general question about the carbon cycle including e.g., sources and sinks of CO2, excess CO2 and the half life for such excess. I looked at this for months a few years back and it made my head ache really bad. As for the effects of CO2 on plant growth generally and crops in particular, there is a fair amount of information on these topics at the Idso website, CO2science.org.
Ken Coffman
>>>If you noticed nearly 1,000,000PPM of N2, O2 and Argon molecules had a temperature and did not radiate much in IR wavelengths, would you think an added CO2 molecule would heat or cool (or do nothing) to the Earth’s surface temperature?<<<<
Symmetric molecules (esp. ones that can NOT become asymmetric because they are monatomic or diatomic homonuclear molecules) do not absorb in the IR. They can however show Raman absorbance. Not sure if this is as strong an effect as IR or not.
However, it is not surprising at all that they don't absorb in the IR. They physically are unable to do so. Water and CO2 on the other hand, can and do.
Espen says: @ March 19, 2012 at 8:28 am
…. if and when this interglacial ends, we are going to need elevated CO2 even more. During the most recent glaciations, CO2 levels fell to plant-starving levels. Now AGW adherents tell us that there will not be any new glaciation any time soon because of the elevated CO2. To me, that sounds like elevated CO2 levels is the perfect insurance against future food catastrophes: Either elevated CO2 stops the next glaciation, or if it doesn’t, it helps plants through it…
_______________________________________
EXACTLY!
We are darn close the the starvation level of CO2 for plants and we are near/at the end of the Holecene. So this whole CAGW hysteria is completely idiotic.
Robert Brown says: @ March 19, 2012 at 8:40 am
…You know, people on this list say things like this, people on the CAGW say the opposite, nobody ever seems to give references. When I sought out references on higher CO_2 and plant growth, I discovered that (not unreasonably) the effect is rather marginal; plant growth is rate limited by many things, and doubling CO_2 isn’t going to e.g. double agricultural productivity….
_______________________________
In the Seeing is believing catagory ~ CO2 and plant response: http://i32.tinypic.com/nwix4x.png
The problem with plants is they do not have feet. Yeah FEET, that means they will use up all the CO2 in the micro-environment and then must wait for the wind to bring them more.
CO2 depletion
WHEAT:
From the people who know and depend on the truth – FARMERS
Hydroponic Shop
…In one peer reviewed article from 2005 it was found that in durum wheat the nitrogen level in the leaves decreased with higher CO2 but at the same time the nitrogen level in the stems and seeds increased. Both biomass and grain yields increased under all nutrient and water regimes where CO2 was higher….
For many many more studies see: http://www.co2science.org/education/reports/epa/CO2ScienceEPACommentsCH6.pdf
In 2 years will will reach the psychological threshold of 400 ppm CO2…..
…… simultaneously we will have stagnant temps for multiple decades, which
will stay on PLATEAU level …..
.Where then remains the amazing “radiative forcing of CO2?”….Lets, see:.
Down to the numbers: Starting point was 280 ppmv, now, according to Adam
Riese, the calculation genius, we will add 43% of this dangerous compound,
thus reaching 400 ppmv…. and considering that a value of 560 ppmv is the
end of an liveable planet according to all IPCC Warmist projections…..the end
will be near folks, doom and gloom all about……you will be radiatively
forced…… better sell your property cheap, the Chinese/Russians/Canadians/Indians
speeden up doomsday now by emitting each year excessive forcing…..
Whether sensitivity is low or high, does not matter….because.doom is around the
corner at 560 ppm CO2 level….
get yourselves ready folks…..
only a few hardy survivalists will remain in caves of the Rocky Mountains….
better buy yourself there a plot, be ahead of your time, prices are already on
the increase.- let me recommend a climate scientist as seller to you……..
JS
Hey, Josh
How about a cartoon of a plant (with feet) chasing a CO2 molecule? (Butterfly net maybe) Might make a great Tee-shirt.
Peter Kovachev says:
March 19, 2012 at 12:31 pm
……….
Hi Peter
On one hand could be a perfectly normal event.
On the other hand, it could be that the Brezhnev propaganda (fearing the US & Canada grain imports embargo) in reporting higher temperatures would be indirectly announcing to the West ‘we are doing fine’. How else to explain that temperature anomaly only within USSR borders was up to +4C (?!), while for the rest of the globe (except for few very minor exceptions) the anomaly was zero or negative. Temperatures do not respect borders, unless decreed to so by the Politburo.
Speculative may be, but a highly unusual event.
http://www.vukcevic.talktalk.net/69-71.htm
Indur Goklani’s work shows that human life benefits more from higher temperatures. Warming would be a good thing. Any survey of biodiversity by latitude will show few species in arctic/antarctic regions, and tremendous biodiversity in the tropics. So warmer temperatures are good for life.
If this article is good news, it is only because of the intense harm done by the environazis believing the opposite. That harm is considerable, both in economic measures, and in human life measures even if we only include the deaths of Arab Spring rioters caused by rising food prices caused by using farmland to grow ethanol for fuel.
The only people hoping global warming will come roaring back are the “team” – the ones that have staked all their credibility on it being reality.
They might be right although I remain unconvinced – BUT – if they’re wrong and it all is due to the Sun then they’re an historical laughing stock.
Strange that the very ones who have been shouting about doom and never ending drought, fire and brimstone are the ONLY ones who actually HOPE they are right !
Can someone answer Don’s question? The models must make some dampening assumptions or the temperature would continue to rise out of control. Can someone describe the dampening mathmatically and describe what, if any, physical justification by the modellers to justify the dampening?
Jim Cripwell says:
March 19, 2012 at 7:35 am
The “no feedback” climate sensitivity is estimated as being about 1.2 C for a doubling of CO2, using the assumption that the “structure of the atmosphere does not change”. In other words, the estimate can be based by ONLY looking at radiation effects. This assumption has never been justified, ansd is almost certainly wrong. The lapse rate almost certainly changes as GHGs are added to the atmosphere.
Since this no-feedback climate sensitivity is the cornerstone of all IPCC estimations, it follows that all these estimations has no basis in physics.
Unfortunately, by weasel wording that the models use a ‘slab’ atmosphere with everything held in stasis – that is NO convection NO water cycle with latent heat etc.. people do not realize that they are being fed a fairy story.
It is also incorrect to talk of a single value for climate sensitivity. The world systems tend to homeostasis so they will assist warming to a point then slowly reverse until they are providing negative feedback – this is just what thunderstorms do. In the tropics you can watch this and set your clock by the storms coming up and cooling the atmosphere.
Robert Brown says:
March 19, 2012 at 8:40 am
++++SNIP++++
You know, people on this list say things like this, people on the CAGW say the opposite, nobody ever seems to give references. When I sought out references on higher CO_2 and plant growth, I discovered that (not unreasonably) the effect is rather marginal; plant growth is rate limited by many things, and doubling CO_2 isn’t going to e.g. double agricultural productivity. Furthermore, with modern farming there really isn’t any difficulty growing enough food for 9 to 10 billion people. The problem has always been that we do not use modern farming methods worldwide, and most world farming is constrained by a lack of energy and modern tools. Providing tractors and diesel and electricity and sowers and harvesters will have a far greater impact on productivity than the CO_2.
But I’m really interested in the latter claim. Over 2/3 of the CO_2 rise is due to land use changes and not fossil fuels? And you know this how, or from what study? I’m not asking in a critical way — I’m asking because I genuinely do not know the answer. Some fraction of our CO_2 anomaly comes from the warming of the ocean. Some of it comes from burning fossil fuels, where we can certainly tally up fuel used every year and CO_2 produced from the given consumption of fuel. Land use changes actually seem IMplausible as a significant factor to me offhand — a distant third. Things are complicated by the fact that the ocean is a dynamic source and sink, by the fact that volcanoes release CO_2, by the fact that e.g. unburned methane from e.g. the Gulf Oil Spill oxidizes to CO_2 (and water) and much more.
So please, if anybody has a really plausible, well-documented source for the currently enormously variable claims concerning anthropogenic and other CO_2, I’d love to see them.
rgb
Robert, if you are really interested there are many many papers that show plant growth improving in CO2. Market gardeners flood their glasshouses with CO2 to improve yields – they don’t do that just to make a point its a hard nosed business decision.
If you want to see References on CO2 and plant growth then you should go to http://www.co2science.org where they keep a database of papers on plant growth and CO2 amongst many other areas of CO2 science. You will have to go there and look though. But just as a start you could look at http://www.co2science.org/subject/n/nutrientnitrogen.php just one area of the site.
Oldseadog says:
March 19, 2012 at 9:47 am
Robert Brown,
Look at the levels of CO2 used in tomato greenhouses in The Netherlands, typically 1200 to 1500 ppm, and look at the yields.
Sorry I don’t have links.
—————————
How can you say that if you haven’t looked. Why should I look if you won’t.
Chuck Nolan,
CO2 enhances plant growth. More is better. There is no downside to current and projected CO2 levels.
Sometimes we need to take off our scientists hat and don on the laymans hat. Wood for trees and all that.
CO2 IS plant food. Plants may not have mouths and teeth to chew with, but CO2 they do consume.
Can anyone name any living entity that does not flourish in the presence of ample food?
Chuck,
I don’t have links because I am a technodinosaur and don’t know how to “do” links.
But I read some farming publications and have friends in The Netherlands.
So it isn’t that I haven’t “looked”.
And see Ian above.
Chip,
Both of the transient studies use models and estimates of past forcings. Routinely, such studies assume use estimates of past solar radiative forcing, and assume that all the climate response to solar variation is due to variation in its radiative forcing, then the studies come up with transient climate responses in those ranges or slightly higher. But we strongly suspect that the coupling of solar variation to the climate involves more than simple radiative forcing. If the greater variation in UV generating the greenhouse gas ozone is important, and/or the magnetic field-cosmic ray coupling is important, then some of the transient response is not due to the radiative component then attributing the sensitivity to radiative forcing results in an estimate that is too high. The assumption that the transient response to CO2 radiative forcing would be the same as that to solar radiative forcing which is coupled to the climate system quite differently was questionable to begin with. Solar couples to the stratosphere, land surface and to the mixing layer of the ocean much more strongly than CO2, while CO2 couples more strongly to the atmosphere and to snow cover surface (which has a lower albedo in the infrared range). To the extent than any solar coupling to the climate turns out to be non-radiative, the assumption of equivalent response is even more questionable.
Bill says:
Symmetric molecules (esp. ones that can NOT become asymmetric because they are monatomic or diatomic homonuclear molecules) do not absorb in the IR. They can however show Raman absorbance. Not sure if this is as strong an effect as IR or not.
However, it is not surprising at all that they don’t absorb in the IR. They physically are unable to do so. Water and CO2 on the other hand, can and do.
Bill,
Could you direct me to some further reading on this? I’m interested in learning a bit more about the mechanism involved.
Rosco says
They might be right although I remain unconvinced – BUT – if they’re wrong and it all is due to the Sun then they’re an historical laughing stock.
Henry says
Why rely on other people if you can determine what happens in YOBY
http://wattsupwiththat.com/2012/03/19/lower-climate-sensitivity-estimates-new-good-news/#comment-928635
Martin Lewit says:
If the greater variation in UV generating the greenhouse gas ozone is important,
Henry says
I am pretty sure it is an important factor,
http://www.letterdash.com/HenryP/henrys-pool-table-on-global-warming
I have not heard from Chip on this blog.
I don’t think he cares too much about us or what we think.
Robert Brown says:
March 19, 2012 at 8:40 am
So please, if anybody has a really plausible, well-documented source for the currently enormously variable claims concerning anthropogenic and other CO_2, I’d love to see them.
The ratio of human CO2 emissions between fossil fuel use and land use changes is quite difficult to obtain: fossil fuel use is rather well known, as result of sales (taxes!), but land use changes is a matter of area and what kind of change. Clearcutting forests gives a net emission of CO2, but planting crops at the same spot or even grassland gives a net sink. Thus these figures are very uncertain. What is known is that even only the fuel use emissions are already near double what is measured as increase in the atmosphere. Any additional emissions from land use change only add to the ratio. Thus anyway, nature as a whole is a net sink for CO2: as well as the oceans as vegetation. See e.g.:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
See further:
http://www.ferdinand-engelbeen.be/klimaat/co2_measurements.html#The_mass_balance
It should be on the record that a report like “Dem Rep. of Congo (a non industrialised country) emitted some 318,942.1” (in 1,000mt units) was made by the World Resources Institute. This is a precision of 1 part in 3 million. Under what circumstances could such a statement be anything other than egregious nonsense?
“Under what circumstances could such a statement be anything other than egregious nonsense?”
Sounds like post-normal science.☺
Before quoting that item about 318.942.1, I need to have a source. I’ve looked in the relevant publications of the World Resources Institute, and can’t find it. Could Richard Verney supply the reference? Many thanks.
Got it! See: http://earthtrends.wri.org/text/climate-atmosphere/variable-935.html. Lots of other nonsense-numbers there too. If anyone is interested in discussing the prevalence and importance of nonsense-numbers, do contact me at jerome.ravetz@gmail.com.
Martin L.;
I think you might enjoy reading http://wattsupwiththat.com/2012/02/22/omitted-variable-fraud-vast-evidence-for-solar-climate-driver-rates-one-oblique-sentence-in-ar5/
Omitted Variable Fraud is rife in climatology; without it, GHG theory fails.
Here’s a perspective on the atmosphere that I think needs to be sustained:
Life made it. The nitrogen, oxygen, and CO2 were all contributed by life processes. The balance is maintained by life processes.
It consists of a huge feedback system — controlled by life.