Arguments
Does CO2 always correlate with temperature (and if not, why not?)
What the science says...
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Surface temperature measurements are affected by short-term climate variability, and recent warming of deep oceans |
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Climate Myth...
There's no correlation between CO2 and temperature
"Twentieth century global warming did not start until 1910. By that time CO2 emissions had already risen from the expanded use of coal that had powered the industrial revolution, and emissions only increased slowly from 3.5gigatonnes in 1910 to under 4gigatonnes by the end of the Second World War.
It was the post war industrialization that caused the rapid rise in global CO2 emissions, but by 1945 when this began, the Earth was already in a cooling phase that started around 1942 and continued until 1975. With 32 years of rapidly increasing global temperatures and only a minor increase in global CO2 emissions, followed by 33 years of slowly cooling global temperatures with rapid increases in global CO2 emissions, it was deceitful for the IPCC to make any claim that CO2 emissions were primarily responsible for observed 20th century global warming." (Norm Kalmanovitch).
At a glance
If you happen to be reading something about climate change in the popular media, be sure to keep an eye out for certain words. The one in this case is 'deceitful'. Why? Because it's an emotive word. It's a good sign that the writer is not a scientist but someone with a political axe to grind.
The heat-trapping properties of carbon dioxide, water vapour and other greenhouse gases were identified over 160 years ago. After that, climate research continued unhindered for many decades. However, by the second half of the 20th century the seriousness of the threat of climate change was well-understood. That led in due course to the involvement of bodies such as the United Nations. Treaties such as the Kyoto Protocol of 1997 followed.
In response, the fossil fuels sector and their political and media associates, perceiving threats to profitability, turned climate science into a political football. With climate science thus politicised, the arena within which research and outreach were conducted had changed. This was no longer a quiet backwater.
That's the historical context. Now we can get to the meat of the myth. The quote above this piece dates from September 2009. Apart from anything else, it's 14 years out of date now. Globally, the ten warmest years since 1880 have all occurred since the statement was made. According to NASA’s Goddard Institute for Space Studies, the average global temperature has increased by 1.4° Celsius (2.5° Fahrenheit) since 1880.
However, global temperature does not correlate exactly with CO2 emissions on a year in, year out basis.There are other well-understood factors that can warm or cool the climate over such short-term periods. You may have heard of El Nino and La Nina. These phenomena involve above- or below-average sea surface temperatures respectively, in the central and eastern Pacific Ocean. Their effects are global.
A strong El Nino can produce a massive global temperature-spike. Such very warm years once led to people making the claim of, "no warming since 1998". Briefly sounding plausible for a few years, it soon became self-evidently incorrect.
Instead, the correct way to look at temperature trends is to examine them over multiple decades - 30 years is standard in climate science. So to answer the question, "where are we now?", one would look at the temperature record from 1992-2022. Doing so takes out the noise, the ups and downs due to El Nino, La Nina and other factors. And the trend is most certainly upwards.
To the newcomer to climate science, it can be difficult to spot misinformation. However, opinion-pieces that accuse bodies such as the Intergovernmental Panel on Climate Change (IPCC) of intentions like deceit should instantly ring alarm-bells.
It is important to point out that the motive for such political misinformation is to spread confusion and doubt. The organisations behind it simply seek delaying any meaningful action. In kicking the can down the road, they try to deflect the pressure to get their own houses in order, and to hell with the consequences.
Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!
Further details
The amount of CO2 in our atmosphere is increasing all the time. On February 26th 2024, according to the monitoring resource Daily CO2, it had exceeded 425 parts per million (ppm). That's up by 3.96 ppm since the same time last year - but more importantly, up from around 280 ppm before the industrial revolution - a 50% plus increase.
Pre-industrial levels of CO2 and other greenhouse gases, like methane and water vapour, were sufficient to keep the Earth’s surface 30°Celsius (54°F) warmer than it would have been without them. Since then, we have added 50% more CO2 - but that doesn't mean the temperature will go up by 50% too.
There are several reasons why. Doubling the amount of CO2 does not double the greenhouse effect. The way the climate reacts is also complex and it can be difficult to separate the effects of natural changes from man-made ones over short periods of time.
As the amount of man-made CO2 goes up, temperatures rise but not at the same rate. Estimates vary - climate sensitivity is a hot topic in climate science, if you’ll forgive the pun. Based on multiple lines of evidence, according to the IPCC Sixth Assessment Report (2021), the "very likely range [for climate sensitivity to doubling of CO2] is 2°C to 5°C".
So far, the average global temperature has gone up by about 1.4 degrees C (2.5 F).
"In 2023, hundreds of millions of people around the world experienced extreme heat, and each month from June through December set a global record for the respective month. July was the hottest month ever recorded. Overall, Earth was about 2.5 degrees Fahrenheit (or about 1.4 degrees Celsius) warmer in 2023 than the late 19th-century average, when modern record-keeping began."
Source: NASA.
The speed of the increase is worth noting too. Unfortunately, as this quote from NASA demonstrates, anthropogenic climate change is happening very quickly compared to changes that occurred in the past (text in bold for emphasis):
"As the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years. In the past century alone, the temperature has climbed 0.7 degrees Celsius, roughly ten times faster than the average rate of ice-age-recovery warming."
Source: NASA Earth Observatory.
Small increases in temperature can be hard to measure over short periods, because they can be masked by natural variation. For example, cycles of warming and cooling in the oceans such as the El Niño-Southern Oscillation (ENSO) cause temperature changes that can mask small changes in temperature caused by CO2 emissions that occur at the same time. That's why scientists measure changes over long periods so that the effects of short natural variations can be distinguished from the effects of man-made CO2.
The rate of surface warming varies year by year, yet the physical properties of CO2 and other greenhouse gases do not change. Neither has the amount of energy arriving from the sun changed significantly in recent decades. But if that’s true, where is this heat going?
The answer is into the oceans. Fig. 1 is a graphic showing where the heat is currently going:
Figure 1: Global Energy Inventory: observed changes in the global energy inventory for 1971–2018 (shaded time series) with component contributions as indicated in the figure legend. Cross-Chapter Box 9.1 Figure 1 (part a) - From IPCC AR6 WGI Chapter 9.
The way heat moves in the deep oceans was poorly understood up until around the turn of the millennium. Since then, vast improvements in measurement techniques, such as the Argo float system, have allowed scientists to far more accurately gauge the amount of energy the oceans are absorbing. Argo floats, numbering several thousands, weigh 20-30 kilograms and are packed with instruments. They typically travel through the oceans around a kilometre below the surface. But they can rise up to the surface or dive down to 2 km. That makes it possible to collect profiles in terms of temperature, salinity and other parameters. So far, over two million such data-profiles have been collected.
Argo data have shown the upper 2,000 metres of the oceans has captured roughly 90% of the anthropogenic change in ocean heat content since the programme started in 1999. Temperatures in the upper 600 metres have been seen to fluctuate with shorter-term climate events like El Niño-Southern Oscillation. In deeper waters, however, there is a more consistent warming trend. In summary, the 700–2,000 metres ocean layer accounts for approximately one-third of the warming of the whole 0–2000 m layer of the World Ocean being mapped by the Argo floats.
So we know that the energy added to the climate system by man-made CO2 is not only apportioned into surface warming, because a large part of the heat goes into the oceans. The rate at which surface temperatures go up is not proportional to the rate of CO2 emissions but to the cumulative total amount of atmospheric CO2. Only by looking at long-term trends - 30 years is the standard period in climate science - can we measure surface temperature increases accurately, and distinguish them from short-term natural variation.
Last updated on 10 March 2024 by John Mason. View Archives
Victor
Just some things to consider, re the 1910-40 period.
Victor Grauer @75.
You say "I cannot agree that any known forcings, including CO2, are capable of accounting for the dramatic temperature rise we see from 1910 to 1940."
As calculated by IPCC AR5, the "known forcings" of human origin for 1940 total 32% of the "known forcings" of human origin for 2011 (the final data in the IPCC assessment). These forcings rise over the 40 years preceeding 1940 roughly proportionately to the 40 year rise preceeding 2011 suggesting a comparison with the resulting global temperature rise above 'pre-industrial' would not be ill-advised. The result of the "dramatic temperature rise,"the 1938-42 temperature (using HadCRUT4) relative to 1850-1900, is 38% of the 2009-13 temperature relative to 1850-1900.
Why do you consider this less-than-dramatic difference between 32% of forcing and 38% of ΔTemp to be the subject of such controversy? Do you assess "the dramatic temperature rise" in some other way?
#76 Glenn Tamblyn
Since I'm not a climate scientist I can't properly evaluate your analysis, but I see no reason to doubt it. However, an explanaton, based on uncertainties as to what might have produced the early 20th century runup is hardly evidence supporting the notion that a correlation between CO2 emissions and global warming has been identified.
#77 MA Rodger
Again, since I'm not a climate scientist I am not in a position to dispute your numbers. However, from what I read in the literature it seems as though most researchers do not see CO2 emissions as a significant contributor to the warmup during this period. Correct me if I'm wrong.
@Victor,
You said, "correct me if I am wrong". You have been corrected multiple times, and even stated flatly, "since I'm not a climate scientist I am not in a position to dispute your numbers"
If you can't dispute the numbers from the climate scientists trying to correct you from being wrong, then I see no reason for you to keep cluttering this forum with your unsupported denialism.
Maybe come back when you do have some supporting evidence?
Sorry about missing the earlier reference to Cawley et al. I printed it out last night, and read it this morning. Judging from the discussion on p. 5, and the very intesting graphs presented in their Figure 3, it does look like they've carried out more or less the same sort of program I suggested back in post 55. Figure 3b does indeed seem to display a correlation of precisely the type on which I was insisting, in which all forcings other than CO2 have been subtracted, so we could get a clearer look at whether a correlation with temperature actually exists — and it looks very much as though it does. Of course, as I indicated earlier, the residue presented in such a graph doesn't necessary represent CO2, as some other, unknown, forcing could be at work.
Regardless of such considerations, however, their model is hedged with some serious caveats:
One wonders whether this last sentence might have been a requirement stemming from peer review. In any case, the honesty is very much appreciated. And the difficulty in producing the desired result is made clear, since so much depends on the existence of prior assumptions, of which the investigators may or may not be fully aware.
Victor Grauer @78.
You seek correction if you are wrong.
You infer that you would like to 'dispute my numbers' but say you are unable because 'you're not a climate scientist'. You are incorrect. The data I use is readily available for use by any layman armed with a spreadsheet, both HadCRUT4 and IPCC historic ERF. I didn't see the point of providing web links @77 as use of these datasets here @SkS is so run-of-the-mill.
Even without a spreadsheet, a pre-industrial global temperature could be readily estimated from a graph of HadCRUT4 and the IPCC forcings totted up. With a 1940 total anthropogenic ERF of 0.613Wm^-2, a climate sensitivity (TCR) of 2ºC, a warming of something like +0.33ºC could be inferred which is pretty-much what HadCRUT4 shows for 1940.
These numbers may be subject to correction; poor eyesight or fat finger syndrome always makes error possible. But you are incorrect inferring that these numbers can be "disputed".
Of course, this represents a trivially simple assessment but shows quite well that the these ERF (of which CO2 is the largest contributor) indeed "are capable of accounting for the dramatic temperature rise we see from 1910 to 1940" and thus your assertion @75 is incorrect.
You are correct @78 to consider that the task of attributing the warming of the early 20th century does rattle round the literature. Serious climate models do not deliver the levels of anthropogenic warming suggested by the simple calculations above. But while literature may debate the role of internal variability & natural forcings, you assert @78 that "researchers do not see CO2 emissions as a significant contributor to the warmup during this period." Anthropogenic forcings (of which CO2 is the largest contributor) remain "significant contributor" within such studies although they are probably not the overwhelming factor in that period. As the IPCC AR5 (this the "review" DSL @74 was likely alluding to) concludes on the matter:-
Thus your assertion @78 is also incorrect.
#81
From http://www.nature.com/ngeo/journal/v8/n2/full/ngeo2321.html :
From http://onlinelibrary.wiley.com/doi/10.1029/2005GL023540/abstract :
From http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282003%29016%3C0426%3ASAGGFA%3E2.0.CO%3B2
victor, you have made a few comments since I last responded, so I shall split my response between two comments. This first one will discuss general issues, while the second will respond explicitly on questions of science.
@71, "sloganeering" is implicitly defined in the comments policy, which you are presumed to have read (on the basis that you are commenting):
The point of the term "sloganeering" is that "discussion" which consists merely of restatements of your position without in fact advancing cogent arguments and/or observational evidence in favour of the position serve no greater intellectual position than to stake out your position as either a "skeptic" or a "warmist". Intellectually, they are no more substantial than the slogans shouted at political rallies. As such, they do nothing to advance discussion.
@73 while the potential for bias is real, I find it extraordinary that you consider it to be a feature of climate science rather than of the "skeptics". There are several, objective measures showing that claims of a "pause" (literally a brief cessation) or "hiatus" (literally a gap) in global warming after 1998 represent (at best) a massive disconfirmation bias by the "skeptics" (as in, they are biased towards accepting any disconfirmation of global warming, no matter how spurious). Not least of these was the choice of the term "pause" for what was at most a reduction in the still positive trend rates. Further objective criteria include the insistence on the use of periods starting with or very near the near record breaking 1997/1998 ENSO and terminating with or just after the 2008, and later the 2011/2012 La Ninas (both unusually strong); and the treatment of the lack of a statistically significant trend as being the lack of a trend simpliciter.
A consequence of this bias is that "skeptics" argue against and "refute" complete misrepresentations of what is actually predicted by the theory AGW. In some cases I have seen, they have "refuted" mischaracterizations of AGW by arguing for what AGW actually predicts. This is certainly the case with regard to the purported 21st century "pause".
What AGW predicts is that, to a reasonable approximation, Global Mean Surface Temperature (GMST) is a linear function of change in forcing plus the effects of short term natural variability such as ENSO. Climate scientists do not pretend to be solar physicists who can predict solar activity in advance. Nor to they pretend to be geophysicists who can predict the timing and intensity of volcanic erruptions. They do not even predent to be economists who can predict the future evolution of anthropogenic emissions. When "predicting" the future, they use a broad range of plausible scenarios for potential future forcings (ie, projections) so that they can predict the plausible range of outcomes rather than the specific outcome. To determine what AGW actually predicts for a specific forcing history you need to run the models (or a crude 2 box model such as Kevin Cowtan's) with the actual forcing history. Further, as short term fluctuations of GMST are influenced by ENSO, you need to further contrain the model to match the actual ENSO fluctuations (as even those models that produce such fluctuations will not match the specific timing and intensity of ENSO events on any given run). Alternatively you need to predict the influence of the divergence from projected values (of forcings and ENSO) and reverse engineer what the observed values would have been had those predicted values actually occured. The later is effectively what Foster and Rahmstorf do.
The upshot is that the features of Foster and Rahmstorf that you consider to be akin to cherry picking are just the features used to determine the mismatch between projected forcing and ENSO values (that climate scientists do not pretend to be able to predict) and the actual historical values so that a comparison can be made between that which climate scientists do purport to predict and observations can be made. That is, they are doing what should have been done by the "skeptics" in the first place, and which is only necessary because the "skeptics" chose rhetorically advantageous misrepresentation (or at best, gross stupidity) over a proper test of the theory they want to criticize.
The problem with your meta-argument then becomes that in any instant where you have a critic of science unprincipled enough, or uneducated enough to completely misrepresent the predictions of the theory, and thereby assert it refuted - any attempt to correct the record by the scientists will be taken by you as proof of the scientist's bias. You have in fact speciously argued for a massive disconfirmation bias that does not even require you to look at the evidence.
Victor Grauer @82.
Trawling the literature to find useful-sounding quotes to add weight to an argument is all very fine but in doing so you do introduce the references you cite into the discussion. And as you fail to indicate why you introduce these four refences @82 I will have to assume that you are defending your bold assertion @78 - "researchers do not see CO2 emissions as a significant contributor to the warmup during this period." I have to say that I see these references actually doing the exact opposite and pulling the rug from under your bold assertion.
Your first reference is to an SkS page but you stick with the 'basic' version when there is also an 'advanced' version that states:-
This seems to be quite definite in saying that AGW (of which CO2 is the largest contributor) is indeed a "significant contributor" but not a dominant one. (Victor - Nil points.)
Your second reference, Thompson et al (2015) 'Early twentieth-century warming linked to tropical Pacific wind strength' says a lot more than 'the early warming was almost 30% of the total when AGW was relatively weak.' (Note this 30% figure chimes well with my rough calculation presented @77 while "relatively weak" is not what you would call an exact evaluation and without context says diddly-squat.) For instance, the paper also says:-
Something strange happened uploading #84. I think it was probably an extranious control character hiding in a cut&paste but will wait and see if it (or our gallant moderators) can sort(s) out the mess before trying a second upload.
[TD] Fixed.
Victor Grauer @82.
Trawling the literature to find useful-sounding quotes to add weight to an argument is all very fine but in doing so you do introduce the references you cite into the discussion. And as you fail to indicate why you introduce these four refences @82 I will have to assume that you are defending your bold assertion @78 - "researchers do not see CO2 emissions as a significant contributor to the warmup during this period."I have to say that I see these references actually doing the exact opposite and pulling the rug from under your bold assertion.
Your first reference is to an SkS page but you stick with the 'basic' version when there is also an 'advanced' version that states:-
This seems to be quite definite in saying that AGW (of which CO2 is the largest contributor) is indeed a "significant contributor" but not a dominant one. (Victor - Nil points.)
Your second reference, Thompson et al (2005) 'Early twentieth-century warming linked to tropical Pacific wind strength' says a lot more than 'the early warming was almost 30% of the total when AGW was relatively weak.' (Note this 30% figure chimes well with my rough calculation presented @77 while "relatively weak" is not what you would call an exact evaluation and without context says diddly-squat.) For instance, the paper also says:-
Fig 1 confirms that AGW was a "significant contributor" to early 20th century warming and it would be a strange reading of the paper that concluded that these "researchers do not see CO2 emissions as a significant contributor to the warmup during this period." (Victor - Nil points.)
Your third reference, Nozawa et al (2005), 'Detecting natural influence on surface air temperature change in the early twentieth century', presents somewhat different findings. It tells us that their initial modelling shows a large impact from GHGs throughout the 20th century, early & late, but when the net contribution of AGW is considered "the warming due to WMGHGs is offset by a cooling due to increases in anthropogenic aerosols, resulting in no significant warming until 1950s."
Yet here the size of the GHG contribution is large enough for them to say "The trend of the global annual mean SAT in GHG is nearly equal to that in NTRL; therefore, without further investigation, we cannot conclude which factors are the main contributors to the observed early warming."
The paper's eventual finding revolves around attribution rather than the power of the various forcings.
This is a better account than your quote @82 from the paper's abstract. It is plain that the message from the paper is that GHG forcing (of which CO2 is the dominant contributor) are a "significant contributor". (Victor - nil points.)
Your final reference is Meehl (2003) 'Solar and Greenhouse Gas Forcing and Climate Response in the Twentieth Century'. This is packed full of interesting stuff but again it would be a very strange reading of it which concluded that these "researchers do not see CO2 emissions as a significant contributor to the warmup during this period." You only have to note Figure 1 which shows the AGW (GHG +sulfate) contribution to the early 20th century warming to be as large as solar's (with volcanic missing). (Victor - Nil points.)
So Victor, that is a pretty impressive score you have achieved @82. Well done you.
#83 Tom Curtis: "while the potential for bias is real, I find it extraordinary that you consider it to be a feature of climate science rather than of the "skeptics"."
OK, before we get any further, I must object to the opposition "climate science" vs. "skeptics." A great many skeptics are in fact climate scientists so that phrase is misleading in this context. As I mentioned earlier, I find it difficult to find a term characterizing those who see CO2 emissions as both a significant cause of global warming, and a clear and present danger to the future of life as we know it. I've used the term "warmist" and I've used "alarmist," but neither seems fair. "Believers" maybe? As oppposed to skeptics? Or "accepters" as opposed to "deniers"? That doesn't sound right either. If anyone has a suggestion I'd love to hear it. Meanwhile, I'll just try to avoid the issue.
Tom: "There are several, objective measures showing that claims of a "pause" (literally a brief cessation) or "hiatus" (literally a gap) in global warming after 1998 represent (at best) a massive disconfirmation bias by the "skeptics" (as in, they are biased towards accepting any disconfirmation of global warming, no matter how spurious)."
There's no question that many climate change skeptics are heavily biased. I cringe when I read some of the nonsense stemming from right-wing ideologues convinced that "climate change" is a communist conspiracy designed to promote world government and the sharing of wealth — or something promoted by greedy climate scientists interested only in government grants. That is bias writ large and there is no place for it in a civil discussion. It's true also that there are more subtle forms of bias that are far more difficult to discern, and I admit that I could be a victim of such bias myself. Why not? And I have no doubt that a great many fellow skeptics, if not all, are biased against the climate change mainstream (is that the phrase I'm looking for?) for one reason or another.
However, we must recognize that, as far as science is concerned, there is an asymmetric relation between someone who offers an hypothesis and someone who critiques it. The burden of proof is on the person offering the theory, not the critic. And since there is always a strong likelihood of any scientist being biased in favor of either his own theory or a theory promoted by the group with which he's associated, special precautions should be be taken to counteract that tendency. Which is why the controlled double-blind experiment is recommended wherever possible.
While a critic may also be biased, there is no burden of proof associated with evaluating someone else's work, nor any need to establish one's lack of bias. The person reviewing someone else's paper, for example, is not normally required to do his own research, conduct his own experiments, double-blind or not, etc. Nor is a critic required to offer an alternative theory. This might seem unfair, but this is the long established convention when a theory is considered in the scientific (or scholarly) world.
To be perfectly clear: the theory in question is the theory that CO2 emissions due to the burning of fossil fuels have been warming the earth steadily over a long time period and as a result placing the world in grave danger. The so-called "hiatus" is an attempt to refute this theory by calling attention to a certain body of data that seems inconsistent with it. Promoters of the hiatus need not offer a counter-theory. All they need to do is demonstrate a serious inconsistency in the "climate change" theory.
With respect to this "hiatus", there's a long long list of studies designed with the intention of disproving it, and I see no reason to uncritically accept any of them — especially when they seem designed specifically to produce a foregone conclusion. The most recent "pause buster," by Karl et al., adjusted the data in such a way as to render literally all these studies superfluous, which should have been a huge embarrassment to the mainstream climate science world, but has on the contraty been accepted with enthusiasm simply because it appears to do the job more convincingly.
The real problem has been swept under the rug. For example, in the light of the data adjustments reported by Karl et al, it would seem that many of the numbers contributing to the results reported in the Foster/Rahmstorf paper are no longer valid, thus the formula leading to the hiatus-breaking result would have to be recalculated and would most likely come out wrong.
The latest turn of the screw is the paper by Fyfe et al., which I'm sure you're aware of, which is critical of all such attempts, insisting that the so-called "pause" is real and needs to be taken seriously. Bias is very likely absent here, especially when we note that Michael Mann himself contributed to this research.
[JH] You have made several points in this post. Please note that excessive repetition is prohibited by the SkS Comments Policy, i.e,
victorag claimed "there is no burden of proof associated with evaluating someone else's work, nor any need to establish one's lack of bias." The falsehood of that claim goes beyond even the other grade school caricatures of science that victor has put forward.
Victor,
Please link your references so they can be checked. Tom Curtis and MA Rodger have shown that your previous papers do not support your claims.
You are getting very repetitive. Consider following the moderators suggestion and stop repeating the same failed assertions. Simply repeating an assertion that has been previously shown to be incorrect will not convince anyone at this site that your arguments have merit. Most of the regular readers have seen your posts at RealClimate and do not need to see them again, especially three or four times.
Your characterization of Karl's paper is false, the paper adjusted the sea surface temperatures as required by science to remove measured biases. The old ship data is obviously biased compared to the new bouy data. You often make false assertions about scientists motives and data. Once several of your assertions are shown to be false, your arguments become not very convincing.
First, in response to the accusation that I'm repeating myself: whatever I said that might be construed as repetition was presented in a different context (a discussion of bias, in response to Tom's assertions that the notion of a hiatus is due to bias — not sure how I could respond to that without repeating some things I'd said earlier.)
Tom Dayton: "victorag claimed "there is no burden of proof associated with evaluating someone else's work, nor any need to establish one's lack of bias." The falsehood of that claim goes beyond even the other grade school caricatures of science that victor has put forward."
An excellent discussion of this issue appears here: http://homepages.ihug.co.nz/~edmin/Pamphlets/Pamphlet%2003%20-%20Scientific%20Method%20and%20the%20Burden%20of%20Proof.pdf
Some excerpts:
With respect to bias: if I can demonstrate that a claim is unsubstantiated, then it doesn't matter whether I'm biased or not. On the other hand, if I'm attempting to establish the truth or relevance of a theory, a hidden bias might be at work in my methodology or my selection of data that makes my theory seem more convincing than it actually is.
[JH] My cautionary note about escessive repetition was prospective.
I also activated the link you provided. Please learn how to use the editing function to activate links.
#89 Michael Sweet:
"Your characterization of Karl's paper is false, the paper adjusted the sea surface temperatures as required by science to remove measured biases. The old ship data is obviously biased compared to the new bouy data. You often make false assertions about scientists motives and data. Once several of your assertions are shown to be false, your arguments become not very convincing."
My characterization of Karl's paper had nothing to do with his claims regarding the validity of his adjustments. So you are the one making the false assertion. What I claimed is that his adjustments made the earlier studies irrelevant, another thing entirely.
Congratulations, Victor. Your understanding of science has advanced from grade school to high school. Look up "naive falsificationism."
It's getting very tiresome to present perfectly logical objections to climate change dogma, only to be greeted by ad hominems, nit picks (thank you, Mr. Rodger), intimidation, misreadings and condescension. Admittedly, this site is run in a far more even handed and decent manner than RealClimate, which is, for the most part, populated by rude imbeciles, encouraged to rave on with little to no supervision.
For the information of all concerned, I am not easily intimidated and I do not suffer fools (you know who you are) gladly. But I am also happy to engage in even handed dialogue with anyone challenging my views, provided they do so with intelligence and respect. And if my attitude is a problem for the moderators then my advice to you is very simple: ban me from the site.
If, on the other hand, you are interested in meaningful, no-holds-barred dialogue on one of the most important topics of the day, then freely open the gate to those like me who have ideas of their own and are not afraid to express them.
[JH] Your comment is a blend of agumentative and off-topic statements, moderation complaint, and sloganeering — all of which are prohibited by the SkS Comments Policy.
If you cannot abide by the SkS Comments Policy, you will relinquish your privilege of posting on this site.
Victor @ 93 and prior :
The argumentation you present, is becoming increasingly silly. Your mentioning of the disproving of the existence of leprechauns - is ridiculous.
Your search for recent "Pause" in global surface temperature rise, has (so far) been unsuccessful. If you have evidence of a claimed Pause, then it seems you have not yet presented it. Please do not withhold such evidence - if it exists, then please present it now.
Earlier, the analogy was made that global surface temperature was the tail on the dog body [ body = ocean ]. Victor, you have made a major Logical Fail, by ignoring the dog and instead concentrating on whether the dog has a tail [ a tail, a cropped tail, or never any tail in the first place ! ].
Your "criticism" needs to: not only point to the absence of a tail - but also point to the absence of a dog.
Since, for well-known physical reasons, the ocean has been warming without Pause - then it becomes not only plausible but highly probable that the "tail" would have no Pause. And the evidence indeed shows no Pause - yes, it shows minor fluctuations as the tail wags a little : but no real Pause.
Your desired "Pause" has become the leprechaun that you must demonstrate.
victorag @87:
Passing over the assumption that "skeptics" are in fact skeptical, rather dogmatically oppositional, surely you have mistated your position. First, and this should be very clear from any excursion to WUWT, the vast majority of "skeptics" have neither qualifications in, nor understanding of climate science. Saying that a "great many skeptics are in fact climate scientists", ie, that a large proportion of the class "AGW skeptic" are also members of the class "climate scientist" is absurd.
I assume you merely mispoke, and intended to say that "a great many climate scientists are 'skeptics'". Even there you are on very shaky ground. Based on surveys of climate scientists, at most 15% and more likely << 10% of climate scientists hold a "skeptical" position on AGW. Among publishing climate scientists, by self assessment only 2.4% of climate scientists thought there published work rejected AGW (see Table 4). So, at best, a very small minority of climates scientists are "skeptics" - sufficiently small that their views cannot be taken as representative of climate science.
And even among the small number of climate scientists who are "skeptics", in most cases there exist clear evidence that suggests they are biased, ie, that they hold their "scientific" opinions for reasons that are primarilly political or religious. A significant proportion of them, for instance, are employed by right wing political think tanks, or have published for or spoken at conferences for such think tanks. Indeed, one of the most noteworthy "skeptical" climate scientists has declared that, "I view my job a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government", a declaration tantamount to saying that as a matter of principle he will distort the science for political ends.
My criticism of the "skeptic's" discussion of the "pause" was that they incorrectly stated the predictions of AGW, and that the responses that you considered to be akin to cherry picking merely established what AGW actually predicted over the relevant interval, and thereby showed that the actual temperature records followed what was expected from the theory. Given that I am flabberghasted by your response. Do you really intend to assert that critics of a theory may assert any phenomenon to be contrary to the predictions of the theory they criticize with no burden of intellectual rigour placed on them to establish that fact? Seriously? If so, your use of a "burden of proof" argument amounts to intellectual legerdemain - a piece of rhetorical prestidigitation that allows you to declare circles are squares and darkness to be light. Even if the " ...burden of proof is on the person offering the theory", that would be completely irrelevant to the case under discussion.
As it happens, even in more general contexts, your principle is useless. That is because, logically, the claim that "GMST did not follow the predicted path given AGW" is also a theory. If a burden of proof applies to those proposing theories, than a proponent of this view has a burden of proof to demonstrate to things, ie, the predicted GMST temperature trend given AGW; and that GMST did not follow that path.
You attempt to support your dictum with a quote @90 from comuter scientist, Stephen Minhinnick. Event there, however, you go awry. Stephin Minhinnick's argume (which I do not accept in any event) specifically relates to the proposition of entities, and the ontologies of climate scientists and (at least well informed) "skeptics" is the same, at least as regards the climate. Neither proposes a distinct set of entities, be it form of radiation, or unusual subatomic particles, or whatever. The only way that you can take Minhinnick's argument to be relevant is if we count abstractions such as trends as being entities. But if we do that, it is the AGW "skeptics" who are proposing an additional entitity. Specifically, AGW proponents propose an underlying linear trend over the period 1975-1997 which continues thereafter, while the "skeptics" propose the existence of a new trend from 1998 onwards. And on that basis, they have singularly failed the burden of proof of showing a new underlyng trend.
And now, apparently, we are in aggreement, except you exempt the "skeptics" from actually having to make the demonstration of inconsistency, which requires not only demonstrating the post 1998 temperature record, but also demonstrating the actual prediction of AGW (not just the projections). And once again, demonstrating that the "skeptics" have not undertaken their task with any intellectual rigour is not akin to cherry picking.
First, and most obviously, Karl et al discusses just one temperature data set, and therefore cannot render analyses of other datasets superfluos. Second, you are not entitled to assume that a reworking of (for example), Foster and Rahmstorf using the latest temperature products would not show an accelerating temperature trend. All you can say from the update of the temperature series is that the former studies are not dated, not that they are superfluos (ie, that repeating the studies would not impact our understanding, or demonstrate any underlying trend greater than the revised temperature trends from Karl et al). Again your argument suggest to me rhetorical legerdemain. You appear to imply that because the "skeptic" rhetoric regarding the purported "pause" has been refuted multiple times, and in several different ways, that of itself refutes the multiple refutations. It is only conspiracy theorests and pseudoscientists who think there theory is confirmed by the mounting of evidence against it.
With reference to my #93 post:
I won't mind if you remove #93 completely, as it was intended primarily for the moderator(s) — as is this post. What it amounts to essentially is a plea for more agressive moderation, not less. In other words: please do your job accross the board and weed out personal attacks, condescending remarks and ad hominem arguments from whatever source. I have the impression that you are doing a far better job in this regard than the moderators at RealClimate — but you could do better. Thank you.
#94 Eclectic: "The argumentation you present, is becoming increasingly silly. Your mentioning of the disproving of the existence of leprechauns - is ridiculous."
Obviously, the "leprechauns" argument was an exreme example. However, as the article makes clear, in principle there is no difference between a claim for the existence of such beings and a claim that CO2 emissions are heating the atmosphere to an intolerable degree that endangers the future of humankind. (In fact, the second assertions looks, on its face, far more ridiculous than the former.) In both cases, the burden of proof is the same — and the challenge for the skeptic is the same. One cannot definitively prove the nonexistence of something, whether it's a leprechaun or an impending disaster. Consequently there is no burden of proof on the skeptic, only the requirement that his argument be sound.
"Your search for recent "Pause" in global surface temperature rise, has (so far) been unsuccessful. If you have evidence of a claimed Pause, then it seems you have not yet presented it. Please do not withhold such evidence - if it exists, then please present it now."
The evidence I presented concerned the lack of a long-term correlation between global warming and CO2 emissions. Since I've been told not to repeat myself, I won't get into that again. However, I can't help but repeat one essential reference, the paper by Fyfe et al, titled Making sense of the early-2000s warming slowdown. Here's what it says in the abstract: "It has been claimed that the early-2000s global warming slowdown or hiatus, characterized by a reduced rate of global surface warming, has been overstated, lacks sound scientific basis, or is unsupported by observations. The evidence presented here contradicts these claims."
If you are unwilling to accept the evidence I've already offered, then at least take seriously the evidence offered in this paper, by a consortium of widely recognized climate scientists.
Before dealing with #95 I'd like to say that Tom Curtis's response is a good example of the sort of thing I am always hoping to find when discussing this issue, yet so rarely do. Tom sticks to his argument and his evidence with no need for sarcasm, condescension or ad hominems. That's much appreciated, so thank you.
"Saying that a "great many skeptics are in fact climate scientists", ie, that a large proportion of the class "AGW skeptic" are also members of the class "climate scientist" is absurd."
Sorry but that looks like a strawman. I never said anything about a "large proportion" — I said "a great many." Which is true. I'm sure you've seen this list before, but just in case. . .
"And even among the small number of climate scientists who are "skeptics", in most cases there exist clear evidence that suggests they are biased, ie, that they hold their "scientific" opinions for reasons that are primarilly political or religious."
My point regarding bias was that we are all biased to some extent. But as far as science is concerned, there is a powerful bias that must be acknowledged which can easily cause a researcher to overlook serious weaknesses in his own methods or arguments. While many skeptics have very obvious biases, if their arguments are sound, their bias can safely be ignored. So it's really better to focus on the arguments and go easy on the accusations of bias, as this really amounts to an ad hominem.
No, not at all. Again you are setting up a straw man. Of course there is a burden of intellectual rigor. But that's not the same as burden of proof. In other words intellectual rigor is required, but it is not necessary for the skeptic to establish any fact. All that's needed is to demonstrate that there is a serious problem (a hidden assumption, an inconsistency, a misreading of data, etc.) with the theory being offered.
". . . logically, the claim that "GMST did not follow the predicted path given AGW" is also a theory." Again: no, not at all. A critique is not a theory. The critic may have a theory of his own, but that's beside the point. Peer review would be impossible if the reviewer needed to establish his own theory before critiqueing someone's paper.
The passages I quoted are statements regarding basic principles of science that are universally applicable. The examples provided pertain to entities, but can obviously be extended to theories of any sort. In any case, the usual AGW argument can be understood as existential and I've read many times assertions that it "really exists," that "climate change is real" and so on. How is that different, in principle, from the assertion that leprechauns are real?
Skeptics need not show a new underlying trend. All that's required is to demonstrate the lack of continuity between the strong upward trend so evident from the late seventies to ca. 1998 and what followed during the following 15 years or so. If the first period appeared to demonstrate a correlation between CO2 and warming, the second period demonstrated the falsity of that assumption. CO2 levels continued to soar while the increase in temperatures slowed considerably. If the relationship is exponential, as has been asserted, then why wouldn't that relationship continue even more convincingly into the 21st century? There is a difference between questioning an assertion and developing a whole new theory that contradicts it. A new theory isn't necessary. The burden of proof is on the person insisting that the correlation is real in the face of what looks like contradictory evidence.
The many papers attempting to explain away the pause were prompted largely by questions raised in the field of climate science itself, not as a response to skeptics. If the later papers managed to replicate the findings of the earlier ones then that would have constituted significant evidence that the mainstream view is sound. But that's not what happened. The later papers either discovered weaknesses in the earlier ones that they attempted to correct, or else simply ignored the earlier attempts in favor of some new wrinkle. Finally, after the adjustments made by Karl et al., many of the numbers used by the earlier researchers were no longer valid, apparently, thus undermining the earlier research. Now if that research were sound it could not have so easily been undermined, no?
[JH] Please take the discussion of the "Pause" to a more appropriate comment thread, i.e., Aerosol emissions key to the surface warming ‘slowdown’, study says by Robert Sweeney of Carbon Brief. Sweeney's article is the most recent on this topic to be posted on SkS.
I will let Tom Curtis continue to dismantle Victor's Gish Gallops of unsupported assertions, but I will comment on one of his links:
The Wikipedia link provided by Victor to support his claim that a "great many skeptics are in fact climate scientists" has a total of 61 living and 7 dead "climate scientists" on it. Of that 68, there is a mixture of botanists, meteorologists, geologists, ecologists, businessmen, chemists, astrophysicists, physicists, etc. Very few are really "climate scientists", except by virtue of their dissemination of tired, denier memes such as those debunked here at SkS. You can look for their names either using the SkS "Cimate MIsinformers" button (in the group below the "Most Used Climate Myths" section along the top left side of each SkS web page), or over at DesmogBlog's Denier Database.
So, really Victor has pointed us to a page of names of fake "skeptics", of which only a very few deserve to be called "climate scientists". To call this "a great many" is indeed strectching things. It reminds me of Project Steve. Tom CUrtis is correct in claiming that the set of "skeptical climate scientists" represents a very small proportion of the set of "climate scientists".
...but Victor seems to have suggested that he also posts at RealClimate. If he is indeed the same Victor, then over at RealClimate he has a long history of adding links to his posts that do not support what he says. From his short appearance here, I would say that the behaviour here matches. Whether his Morton's Demon prevents him from realizing they do not support his case, or he doesn't care and hopes that nobody will follow the links and therefore providing links will bamboozle people, I can't tell. Either way, if Victor claims that a reference says one thing, it wil almost certainly say something else.
Before dealing with #95 I'd like to say that Tom Curtis's response is a good example of the sort of thing I am always hoping to find when discussing this issue, yet so rarely do. Tom sticks to his argument and his evidence with no need for sarcasm, condescension or ad hominems. That's much appreciated, so thank you.
"Saying that a "great many skeptics are in fact climate scientists", ie, that a large proportion of the class "AGW skeptic" are also members of the class "climate scientist" is absurd."
Sorry but that looks like a strawman. I never said anything about a "large proportion" — I said "a great many." Which is true. I'm sure you've seen this list before, but just in case. . .
"And even among the small number of climate scientists who are "skeptics", in most cases there exist clear evidence that suggests they are biased, ie, that they hold their "scientific" opinions for reasons that are primarilly political or religious."
My point regarding bias was that we are all biased to some extent. But as far as science is concerned, there is a powerful bias that must be acknowledged which can easily cause a researcher to overlook serious weaknesses in his own methods or arguments. While many skeptics have very obvious biases, if their arguments are sound, their bias can safely be ignored. So it's really better to focus on the arguments and go easy on the accusations of bias, as this really amounts to an ad hominem.
No, not at all. Again you are setting up a straw man. Of course there is a burden of intellectual rigor. But that's not the same as burden of proof. In other words intellectual rigor is required, but it is not necessary for the skeptic to establish any fact. All that's needed is to demonstrate that there is a serious problem (a hidden assumption, an inconsistency, a misreading of data, etc.) with the theory being offered.
". . . logically, the claim that "GMST did not follow the predicted path given AGW" is also a theory." Again: no, not at all. A critique is not a theory. The critic may have a theory of his own, but that's beside the point. Peer review would be impossible if the reviewer needed to establish his own theory before critiqueing someone's paper.
The passages I quoted are statements regarding basic principles of science that are universally applicable. The examples provided pertain to entities, but can obviously be extended to theories of any sort. In any case, the usual AGW argument can be understood as existential and I've read many times assertions that it "really exists," that "climate change is real" and so on. How is that different, in principle, from the assertion that leprechauns are real?
Skeptics need not show a new underlying trend. All that's required is to demonstrate the lack of continuity between the strong upward trend so evident from the late seventies to ca. 1998 and what followed during the following 15 years or so. If the first period appeared to demonstrate a correlation between CO2 and warming, the second period demonstrated the falsity of that assumption. CO2 levels continued to soar while the increase in temperatures slowed considerably. If the relationship is exponential, as has been asserted, then why wouldn't that relationship continue even more convincingly into the 21st century? There is a difference between questioning an assertion and developing a whole new theory that contradicts it. A new theory isn't necessary. The burden of proof is on the person insisting that the correlation is real in the face of what looks like contradictory evidence.
The many papers attempting to explain away the pause were prompted largely by questions raised in the field of climate science itself, not as a response to skeptics. If the later papers managed to replicate the findings of the earlier ones then that would have constituted significant evidence that the mainstream view is sound. But that's not what happened. The later papers either discovered weaknesses in the earlier ones that they attempted to correct, or else simply ignored the earlier attempts in favor of some new wrinkle. Finally, after the adjustments made by Karl et al., many of the numbers used by the earlier researchers were no longer valid, apparently, thus undermining the earlier research. Now if that research were sound it could not have so easily been undermined, no?