Scepticism is often discussed in connection with climate change, although the concept is often abused. I therefore thought it might be interesting to go back and see what the epitome of 20th Century sceptics, Bertrand Russell, had to say on the subject. This is extracted from the Introduction to his ‘Sceptical Essays’ (1928):
I wish to propose for the reader’s favorable consideration a doctrine which may, I fear, appear wildly paradoxical and subversive. The doctrine is this: that it is undesirable to believe a proposition when there is no ground whatever for supposing it true.
First of all, I wish to guard myself against being thought to take up an extreme position. … [Pyrrho] maintained that we never know enough to be sure that one course of action is wiser than another. In his youth, … he saw his teacher with his head stuck in a ditch, unable to get out. After contemplating him for some time, he walked on, maintaining that there was no sufficient ground for thinking that he would do any good by pulling the old man out. … Now I do not advocate such heroic scepticism as that. I am prepared to admit the ordinary beliefs of common sense, in practice if not in theory. I am prepared to admit any well-established result of science, not as certainly true, but as sufficiently probable to afford a basis for rational action.
….
There are matters about which those who have investigated them are agreed. There are other matters about which experts are not agreed. Even when experts all agree, they may well be mistaken. …. Nevertheless, the opinion of experts, when it is unanimous, must be accepted by non-experts as more likely to be right than the opposite opinion. The scepticism that I advocate amounts only to this: (1) that when the experts are agreed, the opposite opinion cannot be held to be certain; (2) that when they are not agreed, no opinion can be regarded as certain by a non-expert; and (3) that when they all hold that no sufficient grounds for a positive opinion exist, the ordinary man would do well to suspend his judgment.
So does this provide any clarity? Russell clearly doesn’t support an extreme where everything must be continually doubted and nothing can ever be known. As he later suggests, that kind of position would make it philosophically troubling to ever get out of bed in the morning. This extreme attitude does however rear up in climate discussions where an interesting debate on the impacts of human-related increases of greenhouse gases on, say, the atmospheric circulation, often becomes bogged down in how do we know that GHGs are increasing at all, whether they are affected by human activity, and how it’s all down to the sun anyway. Since all of these things have been discussed ad nauseum here, here and elsewhere, that kind of ‘scepticism’ (more accurately described as contrarianism, or ‘la-la-la-I-can’t-hear-you’-ism) serves only to waste time. Since working scientists are all busy people, this is usually why we tend to cease communication with such contrarians very quickly.
If we relax the above-mentioned constraint requiring ‘all experts’ to agree (something never achieved in practice) to ‘the overwhelming majority of experts’, we can substitute in the IPCC for ‘experts’ in the quote. It’s important to note that Russell does not claim that if all experts are agreed, then one must agree with them, but solely that being certain of the opposite opinion in such circumstances is not wise. It is implied by his opening statement then that having ‘all experts’ agree something is reasonable grounds for supposing something to be true. Similarly, if the IPCC concludes that something is highly uncertain (such as the magnitude of changes in aerosol indirect effects), then there are no good grounds for assuming otherwise.
Can someone be productively sceptical? Of course. Firstly, one needs to be aware that scepticism about whether a particular point has been made convincingly is not the same as assuming that the converse must therefore true. Sometimes scientists just don’t use the best arguments they could (particularly if they are a little out of their field of expertise) and these points can, and should, be challenged. One example would be the use of an incorrect ‘correlation implies causation’ argument. For instance, the strong correlation of CO2 and temperature in the Antarctic ice core records does not in and of itself imply that CO2 has a radiative impact on climate. However, additional analyses that look at the factors controlling temperature during the ice ages give strong grounds for believing that CO2 does play an important role. Therefore while the use of the correlation argument alone is wrong, the converse of the conclusion is not necessarily true.
Secondly, it helps to have done the homework. It is highly unlikely (though not impossible) that the sceptical point in question has not already been raised in the literature and at meetings. If a particular point has been argued to death previously and people have moved on (either because it was resolved, moot or simply from boredom), there is little point bringing it up again unless there is something new to talk about. Obviously, a good summary of how the point was dealt with can be educational though. Arguments about whether the current CO2 rise is caused by human activity fall clearly into this category.
Thirdly, scepticism has to be applied uniformly. Absolute credence in one obscure publication while distrusting mountains of ‘mainstream’ papers is a sure sign of cherry picking data to support an agenda, not clear-thinking scepticism. Not all papers get the peer review they deserve (or require) and the literature has many examples of dubious logic and unsupported interpretation. Sometimes this becomes very clear (for instance, the Soon and Baliunas saga at Climate Research), and sometimes it goes uncommented upon. But what about Galileo? Wasn’t he an obscure scientist persecuted by an entrenched mainstream? Yes, but Galileo is celebrated today because he was correct, not because he was persecuted. If an idea is right, it will be supported by additional evidence and will lead to successful predictions – at which point it will likely be accepted. The ‘Galileo’ defence (and its corollary the ‘establishment conspiracy’) are usually a sign that the additional evidence and the successful predictions are lacking.
Finally, it should be understood that constructive scepticism is a mainstay of the scientific method. The goal of science is to come closer to a comprehensive picture of how the real world works, with scepticism essential to toughening up scientific ideas, though alone, it is insufficient to move understanding forward. It isn’t essential that every true sceptic have an alternative theory ready to go, but they should bear in mind that our picture of how the world works, though incomplete, rests on many different foundations. If it sometimes seems that the scientific consensus is resistant to new ideas, it is because that consensus has already been tested in many ways and yet still stands.
Much of what passes for ‘debate’ on climate change in the popular media, is often framed as the ‘scientific consensus’ vs. the ‘sceptics’. A close examination of these arguments (for instance, as outlined in a recent Wall Street Journal editorial) doesn’t reveal much that could be described as true scepticism since they often use the fallacious reasoning that we discuss above. However, since scepticism has a (justifiably) long and noble tradition in science, the framing device is quite powerful (despite the lack of connection with any actual scepticism). As with the intelligent design controversy, agenda-driven opposition has often managed to cloak its contrarianism with the mantle of scepticism. So, while many contrarians pay lip service to the legacy of Russell (or even Pyrrho), forgive me if I remain a little sceptical…
Re #91, “The problem with the Sun being the cause is that we pretty much know all the Sun’s cycles on a human time scale.” How do you know this? This assertion appears to be contradicted in The IPCC report “Climate Change 2001: Working Group I: The Scientific Basis”. Section 6.11.1.2 “Reconstructions of past variations of total solar irradiance” states “As direct measurements of TSI are only available over the past two decades it is necessary to use other proxy measures of solar output to deduce variations at earlier dates…However, direct solar proxies other than the sunspot number cover too short a period to reliably detect such a trend. Thus, it is not clear which proxy, if any, can be satisfactorily used to indicate past values of TSI.” http://www.grida.no/climate/ipcc_tar/wg1/245.htm
Section 12.2.3.1 “Natural Climate Forcing” states: “The estimation of earlier solar irradiance fluctuations, although based on physical mechanisms, is indirect. Hence our confidence in the range of solar radiation on century time-scales is low, and confidence in the details of the time-history is even lower.” http://www.grida.no/climate/ipcc_tar/wg1/448.htm
re 100.
True, regular weather broadcaster and educators could explain global warming to the public, then pass along the latest official global warming predictions and perhaps what the consequences could be. But, even if their advertisers allowed that to happen, the media has not been given basic information on global warming from official sources, not that I know of.
I’d like to see comments to RC from media, and local and state gov employees and others about any advice in dealing with global warming which they may have received from official contacts in the fed gov agencies. Did they formally or informally ask for fed agency advise in dealing with the public on global warming? Any documentation on what was said?
Continuing one of the parallel discussions that have broken out here, one can only evaluate the postings of Roger Pielke Sr. (and to a large extent Jr.) if you have an appreciation of the scientific “culture” of the State Meteorologists. With their intense local focus, they are often somewhere between uncaring and hostile to global climate effects, but as others have pointed out they are key nexus points for data gathering and dissemination (e.g. precipitation forcasts). Given the public prominence (the INTERNET is public you know) of these two, Michaels, Christy and others, I think this is something that has to be brought out.
On the other hand, the “global climate community” (for example, GISS, Hadley Centre, etc.) has to work harder at showing how its work is relevant to the sub 1000 sq km scale that the State Meteorologist work at and making it clear how the data gathered at those scales are needed for global scale research. If you ask me, a lot of the pushback from Roger Pielke Sr. is a cry for attention to things he thinks important.
I anticipate that all sides will shout at me that they are doing this, but, again obviously, at the sub 1000 sq km scale it ain’t working guys.
Mea culpa, should have been State Climatologists in 103. I know, weather is not climate.
A big job of the “educators” would be to debunk the alarmists for global warming. The pro-global warming people never seem to attempt to debunk the crazies who argue in favor of global warming. Don’t they understand that crackpots are easy to debunk and then the whole idea of global warming looks suspect?
For example, the NY Times ran articles this summer on Alaska melting and all. It was all blamed on global warming driven by CO2. No responsible person in the climatology community came forward to debunk global warming as a cause of this. Why not? Now, when I visit a site such as this:
http://climate.gi.alaska.edu/ClimTrends/Change/4904Change.html
I am quite willing to believe the worst about global warming protagonists. Afterall, if global warming were real, they wouldn’t have the need to exaggerate, would they?
[Response: We didn’t deal with that story specifically, but we have criticised unsupportable over-reactions, for instance, on Global Dimming or the hurricanes issue. We will continue to do so as things come up, however, in the same way that we can’t critique every occurence of a ‘contrarian’ argument, we can’t critique every piece where someone confuses climate change with weather. -gavin]
re 105.
I think the piece by the Alaska Climate Research Center that joel hammer referenced should be critiqued. The article is titled Temperature Change in Alaska: 1949 – 2004. Here is my quicky review (in parenthesis).
The period 1949 to 1975 was substantially colder than the period from 1977 to 2004, (True)
… however since 1977 little additional warming has occurred in Alaska with the exception of Barrow and a few other locations. (False)
In 1976, a stepwise shift appears in the temperature data, which corresponds to a phase shift of the Pacific Decadal Oscillation from a negative phase to a positive phase. (Misleading, A shift to a sharper increase in global temperatures also occurred in mid-late 1970s).
Synoptic conditions with the positive phase tend to consist of increased southerly flow and warm air advection into Alaska during the winter, resulting in positive temperature anomalies. (Misleading, larger increases in winter temperatures are a symptom of greenhouse global warming).
Overall critique (Misleading).
Friday, December 30, 2005 on PBS
(Check local listings at http://www.pbs.org/now/sched.html)
==================================================================
This week on NOW:
* Global meltdown. NOW goes inside the battle over global warming.
What has scientists alarmed and why isn’t Washington listening? Find
out in HOT WORLD, COLD COMFORT.
“Scientists are not disinterested truth seekers,” according to David Goodstein, vice provost of Caltech and an expert on research ethics. “They are more like players in an intense, winner-take-all competition for scientific prestige and the resources that follow from that prestige.”…
I wonder if any of you climate scientists would like to refute Mr. Goodstein’s assertions. In my opinion, as long as people see scientists as less than open-minded then they are less likely to accept scientific assertions about the approach of the end of the world.
Also, the real argument is not so much about the science of AGW. (Although there are plenty of different ideas competing for attention.)
The real argument is, that if GW is really due to fossil fuel burning, what can be done about it short of sending the modern world into a depression with a return to the living standards of the 1930s. That is why I believe the only way this or any other developed country can be convinced to start cutting back on fossil fuel usage is if it becomes clear that it will be to the country’s advantage both fiscally and for national security.
It is all well and good to tell people that in a 100 years things are going to be very bad here. Most people are much more worried about paying the rent/mortgage, the utility bill, fueling up their car, and other such issues than they are about what will happen climatically in 100 years. It’s just human nature.
But if you can convince them that energy conservation and new clean energy technologies will put money in their pockets and make them more secure, most reasonable people will listen.
re 106.
The article by the Alaska Climate Research Center (105.)
says: … however since 1977 little additional warming has occurred in Alaska with the exception of Barrow and a few other locations.
That is false. The difference in annual temperature from 1949, 1950s compared to 2004 was greater than 4.2 Deg. F for 9 of 18 stations, as shown in Table 1.
Table 1. Temperature comparison for stations in Alaska
http://groups.yahoo.com/group/ClimateArchiveDiscussion/message/562
re 108.
On Truth, Fact, Values, Climate Change, and Doughnuts — A Guest Commentary
December 29, 2005 – By Peter H. Gleick, the Pacific Institute
Excerpt:
Another fundamental difference between supporters of real science and pseudo-science is that real scientists are willing to change their minds in the face of sufficient and compelling contradictory evidence. Changing their minds is something supporters of creationism and intelligent design, or skeptics of climate change, seem unable, or unwilling, to do.
http://www.enn.com/today.html?id=9556
Actually, I’d like to reinforce it. But remember that “an intense, winner-takes-all competition” means that we are always looking for ways to make our mark by overturning (or at least modifying) the established status quo. When someone gets something wrong, there are usually plenty of others ready to correct them, and even the most sceptical would have to accept that this procedure has been stunningly successful in uncovering the truth across a vast range of fields in recent decades and centuries even though the individuals themselves are merely human with all the flaws that this entails. You are welcome to suggest any further improvements, of course…
Climate research does not consist of men in smoke-filled rooms all conspiring to decide what “the consensus” will be (I don’t know, but strongly suspect, that the IPCC process sees its share of forthright discussion). But one can go too far in the opposite direction – anyone whose sole contribution is to criticise and denigrate, without making any positive contribution at all, is unlikely to be highly regarded and will find few are prepared to collaborate or help them. IMO it’s best treated as a friendly competition – we are all trying to uncover aspects of the truth, and are all trying to get ahead of each other. More like golf than boxing, perhaps.
Re: 106:
I think it is fair to say “… however since 1977 little additional warming has occurred in Alaska with the exception of Barrow and a few other locations.” If you look at the map with the individual values (or at the table) for the full period you see significant warming at every station:
http://climate.gi.alaska.edu/ClimTrends/Change/4904Change.html
If you then look at the later period, you see the significant warming is limited to a few stations:
http://climate.gi.alaska.edu/ClimTrends/Change/7704Change.html
The Pacific Decadal Oscillation did indeed shift phases in the summer of 1976, which can be seen here:
http://jisao.washington.edu/pdo/PDO.latest
Here is a nice graphical display of what the PDO is (believed to be):
http://tao.atmos.washington.edu/pdo/
I should also mention that the suggestion of a PDO signature in the temperature record does not in any way refute the possibility of a simultaneous global warming signature. They are different things.
Since we both (Pat and I) live in Minnesota, let me provide a local example of “synoptic” explanations in non-competition with global warming explanations.
After the winter of 1985-86, our winters in most of MN (and the Upper Midwest) became comparably tame. We began setting more warm-type records (daytime highs, and record warm “lows”). The benign winters continued into the mid 1990s. Then, it seemed the ante was upped; beginning with the winter of 1997-98, we have not merely broken records, we have shattered them. This continues. We have gotten used to bare ground in December. Our potential severe weather season has expanded on both the early and the late ends, our extreme precipitation and flash flooding season has expanded also. In my opinion, this is our very own, personalized global warming signal. No local experts have found a remotely compelling counter-argument. That is the large-scale explanation. On the synoptic scale, the Polar jet has spent more time to our north, we have had more days with warm air advection (i.e., southerly winds), and we have had fewer “strong” mid-latitude cyclones passing to our south…to name just a few “failed” mechanisms. One explanation (e.g., global warming) does not negate the other (e.g., synoptic conditions). And this whole long-winded bit was just to say that the folks at the Alaska Climate Research Center are not saying (or denying) what it appears you think they are.
I am wondering if there has been any response to this piece skepticism by C. R. deFreitas of the Aukland NZ School of Geography and Environmental SCinece.
http://www.friendsofscience.org/documents/deFreitas.pdf
Granted even though it is published by The Bulletin of Canadian Petroleum Geology, I am not qualified to judge it.
Thanks.
[Response: Seems to be pretty poor stuff. From near the start: Contrary to the IPCC predictions, global temperature has not risen appreciably in the last 20 years. Most surface temperature data free from the influence of surrounding buildings and roads show no warming. Data from satellites support this. This is all wrong: T *has* increased (not sure why he says “predictions”); rural trends are similar to urban ones (here); satellites support the sfc record (here) and the models – William]
re 112. Kenneth, you wrote: If you then look at the later period, you see the significant warming is limited to a few stations: http://climate.gi.alaska.edu/ClimTrends/Change/7704Change.html
I disagree with the Alaska Climate Research Center saying that … since 1977 little additional warming has
occurred in Alaska with the exception of Barrow and a few other locations. That is false, according to the data that I found at the Western Regional Climate Center, at http://www.wrcc.dri.edu/
I added a table with annual temperature data at Alaska stations for 1977 and 2004, and differences to my: “A critique: Temperature Change in Alaska: 1949 – 2004 (updated)”, at:
http://groups.yahoo.com/group/ClimateArchiveDiscussion/message/563
Please take a look at my critique which I updated this morning. Any additional comments that you may have would be appreciated.
Re 110 (and P. Gleick’s Dec. 29 article on ENN):
This article repeats the fallacy that one must be an expert with an alternative theory before one points out another’s errors:
The article also laments about those who “are locked into a certain way of seeing things, a world view that clouds their vision when presented with evidence that contradicts their beliefs and leads them to twist their interpretations and manipulate facts”. This sounds like some on either side of the debate to me.
[Response: Not so sure about your point here. It is true that a criticism can be made of a piece of science (as described above), without having a better explanation at hand. However, it is also fair to point out (as Gleick does) that in fact there isn’t a ‘skeptic’ theory that provides a better explanation. -gavin]
Michael Tobis in comment 54 opines that “no one has come up with a reasonable way of testing which of these pressures dominate” — the pressure to overstate risks and the pressure to downplay them.
But in the case of AGW risk, the question, “Who funds the funders” seems illuminating to me because the answer, to a very significant extent, is “fossil fuel consumers”. Because of large special tax revenues these consumers provide, funding agencies and the political sector that supports them have an interest in not hearing bad news about the effects of fossil fuel use.
— Graham Cowan, former hydrogen fan
boron as energy carrier: real-car range, nuclear cachet
Re: Sam (113). I have learned one very interesting thing from your referenced paper. In Chapter 1 of the IPCC TAR, the following statement is made:
“The fact that the global mean temperature has increased since the late 19th Century and that other trends have been observed does not necessarily mean that an anthropogenic effect on the climate system has been identified. Climate has always varied on all time-scales, so the observed change may be natural.”
I have double checked this, and it is correct (Section 1.3.2, p.97). I do not repeat this to say whether I concur with it or not, but rather to highlight that the IPCC – often quoted in these pages as representing THE ‘scientific consensus’ – clearly does not in itself represent a concensus.
Correction to link in #107
http://www.pbs.org/now/science/climatedebate.html
Will be showing periodically over the next days
http://www.pbs.org/now/sched.html
re 117:
The statement you quote from the IPCC is hardly controversial, rather it seems quite obvious. It does not therefore follow that the report “clearly does not in itself represent a concensus”. grida.no seems down at the moment so I can’t check the context of this remark, nevertheless, acknowledging that an observed change may be natural does not preclude assessing more evidence and concluding that it isn’t.
Re: PHEaston (117)
The quoted sentences can be found under the title “Detection and Attribution” here. The quote is indeed correct as far as it goes. However, the next sentence says:
before a discussion of how a human influence can be detected. A little later it concludes:
So the quoted passage is simply saying that, just because the climate is changing doesn’t necessarily mean that it is due to human activities, which is trivially correct. It isn’t saying that climate change isn’t due to human activities, and so isn’t in disagreement with the IPCC consensus.
Re: 120. I agree with your clarification. I bet that had one or two people sweating!
It is interesting to see that, just like the global warming skeptics, no data will convince the true believers (eg. The Alaska Climate center data). Every piece of data that contradicts global warming must be shown to be false or irrelevent or misconstrued by the people who understand the data best. For example, in a stunning display of political correctness, the cooling of Antarctica was declared irrelevent to global warming by the author of the study which documented this cooling. Unboubtedly he had expected to find Antartica cooling. I suppose this observation will be ignored or explained away as having nothing to do with global climate change.
The fact that Alaska is not heating up and that Antarctica is cooling does not of course disprove global warming, but to ignore these findings is just bad science. A true scientist would recognize that anomalies (ie. Deviations from the expected) are NOT the enemy. They are opportunities to extend your understanding. Who knows. Maybe there are really important things we don’t understand about climate.
Verily, there is little to choose between the antagonists in this debate.
[Response:http://www.nerc-bas.ac.uk/public/icd/gjma/trends2004.col.pdf – William]
re 122
joel,
The article (2005) by the Alaska Climate Research Center (ACRC) states:
… since 1977 little additional warming has occurred in Alaska with the exception of Barrow and a few other locations. …
http://climate.gi.alaska.edu/ClimTrends/Change/4904Change.html
The ACRC statement above is false.
I proved that the ACRC statement above is false in Table 1a. of my 30 Dec 30 2005 post to ClimateArchiveDiscussion, Subject: ‘A critique: Temperature Change in Alaska: 1949 – 2004 (updated)’, at:
http://groups.yahoo.com/group/ClimateArchiveDiscussion/message/563
Table 1a was based on data from the Western Regional Climate Center (WRCC), which is located in Reno, NV. The WRCC supports a three-partner National Climate Services Program – the partners include: National Climatic Data Center (NCDC), Regional Climate Centers (RCC’s), and State Climate Offices. see: http://www.wrcc.dri.edu/
Re: 107
Pat, I watched the NOW program on PBS. The message that I got from that program was that all people who do not agree with the premise that AGW is responsible for climate change are funded by the oil industry. The reporter made this point over and over throughout the show even though only he and one of the people interviewed made this case.
I was very interested to see Richard Alley showing off his ice cores in his freezer lab.
Reading through this thread, I was struck by the absence of discussion about the recent Hwang controversy (debacle?) Here is clearly a situation where a good dose of skepticism would have served the interest of science and Science.
Re 124
Brooks,
I haven’t seen the PBS NOW program, but I plan to watch it soon. I read a transcript of it yesterday. One can view some ice cores in a freezer lab at the linked to article, below.
http://www.rockymountainnews.com/drmn/local/article/0,1299,DRMN_15_4310949,00.html
Might need to put the link together to get there?
Earth’s uneasy breathing measured on Niwot Ridge
Gases collected at 11,500 feet reveal nature’s responses to warming world By Jim Erickson, Rocky Mountain News
December 13, 2005
NIWOT RIDGE
#117, 120 and 121. In 117 PHEaston artfully snips out a fragment from the IPCC TAR, creating an impression that is not supported (indeed essentially contradicted) by the complete piece from which it is taken. When Brent Jackson calls him on this in 120, Easton artfully tells us in 121 that he was just funnin’.
Pat Neuman said in 51, “My wish is for writers here to be specific, not imply things or make insinuations which may cause others to make false assumptions about what they meant in their writings.” PH just told him not to bother.
So the issue becomes should anyone offer any respect or credibility to Easton and his crew. I think not.
Re: 126
Thanks Pat. The RMN article showed storage of ice cares, but not handling of the cores. The video of Alley in his lab showed Alley handling his ice cores.
From http://www.amasci.com/feynexpt.txt
Richard Feynman told a national science teachers convention in 1966:
“We have many studies in teaching, for example, in which people make observations, make lists, do statistics, and so on, but these do not thereby become established science, established knowledge. They are merely an imitative form of science … The results of this pseudoscientific imitation is to produce experts …. Learn from science that you must doubt the experts. As a matter of fact, I can also define science another way: Science is the belief in the ignorance of experts.”
(The Physics Teacher, 7 September, 1969, 313-320)
Re #129
This is a nice quote and good advice, but it is for scientists in the expert’s field or others seriously studying a topic. If you are a climate scientist then absolutely you should not just believe everything you read in the journals of climate research, but if you are not knowledgable in the field and can not understand all the technical details that support an expert’s conclusion then you need to have a little trust, especially when all the experts agree. Absent some trust somewhere you will spend your life reinventing wheels.
This gets to the central point of this RC article and what it means to be an intelligent skeptic. A true skeptic in the sense that Richard Feynman is advocating above will doubt the experts and search out the areas of ignorance BUT they will come up with the answers and corrections (or confirmations!) themselves and that is the spirit of science. The “septic” on the other hand uses sentiments like Richard Feynman’s above only as something to hide behind while offering no clarity, no conflicting evidence, no logic: just FUD.
Unfortunately it is trivial to learn just enough to raise plausible sounding objections thus forcing uninformed onlookers to feel it is too complicated for them to decide for themselves. Once this is acheived the onlooker you are trying to manipulate is much more vulnerable to emotional or other irrational influences and a once severly one-sided scientific debate is now an even playing field.
Unfortunately it is trivial to learn just enough to raise plausible sounding objections thus forcing uninformed onlookers to feel it is too complicated for them to decide for themselves. Once this is acheived the onlooker you are trying to manipulate is much more vulnerable to emotional or other irrational influences and a once severly one-sided scientific debate is now an even playing field. [link added]
Well said sir. I hope you don’t mind me using it, Coby, unless you have an intellectual property copyright, or have inserted spyware into it :o) . If I could add just one thing: a phrase seen often used by contra/denialists, rather than ‘plausible-sounding objections’, is ‘serious questions’.
Kenneth Blumenfeld’s students would do well to mark your phrase when scanning or Googling. In addition, the appeals to emotion is another clue.
Best,
D
Thanks, Dano :) Feel free to use it, I believe I gave up any copyright claims by tacitly accepting (11) of RC’s Comment Policy anyway, though I make no guarantees about embedded spyware!
Of course this tactic is greatly facilitated by the “sound bite” nature of news reporting in general and the media’s infatuation with the false objectivity of balance. That link is to an RC post, of course concerned with GW issues, but it is an affliction that crosses many journalistic domains.
I do have a sense that the septics have lost a lot of ground this last year, having fewer and fewer plausible objections as the research seems to pour in. The issue has been cleverly hijacked though and it will be some time before the claims that the news is getting more dire because the “GW advocates” are getting more desperate will lose all credibility in a society so nicely conditioned to distrust all those “UN funded liberal scientists”
Coby,
Two points:
1. Saying that all experts agree is hyperbole. I know of no subject upon which all the experts are in agreement.
2. Saying that something is true because experts agree is a logical fallacy. Whether it is an appeal to authority or an appeal to popularity, it is a nevertheless a logical fallacy.
Believing something because the vast majority of data supports that belief is rational behavoir.
Re #133:
I think this is itself a bit of a hyberbole. Depending on how specific or general the question is there are surely many things where all the experts are in agreement. Astronomers and the distance to the sun. Geologists and the approxiamate age of the earth. Cardiologists and the function of the heart…You get my meaning.
For climate science and global warming, I grant you it is a hyberbole to say “all experts agree” absent a specific general topic. I would not hesitate to say that all experts agree the temperature is rising and has risen over the last century. After that we are talking about degrees of majority I suppose, each issue with its own consensus or controversy. My personal impression is that it is a fair statement that the large majority of climate experts agree that anthropogenic GHG forcing is the primary driver of the 20th century warming trend and this trend will very likely continue through the 21st century.
I agree. But I did not say that. I said that faced with a consensus of scientific opinion and absent personal expertise one should have a little trust. I also said that absent some trust somewhere you will spend your life reinventing wheels but I should have said you will more likely spend your life walking.
Yes, any group of experts could be wrong. But to people who are so quick and persistent to point that out only because they do not like the implications I say “put up or shut up”. It is not enough to say “we used to believe in ether” or “we don’t know everything” or “the models have flaws”, if there is a serious doubt investigate it, if there is an alternate theory present it, if there is a better model run it.
I have looked at as much of the science as I have time and stomach for and I continue to follow it. It looks solid to me. I have also entertained quite a few contrarian arguments and 99% of them are obviously, seriously flawed. The 1% I keep in mind, but a one in a hundred chance that we are not in grave danger is no justification for “staying the course”
Agreed. Start here: http://www.grida.no/climate/ipcc_tar/wg1/
I’d like to come back to the core issue. I find your interpretation of Bertrand Russell utterly dishonest. When you say “If we relax the above-mentioned constraint requiring ‘all experts’ to agree (something never achieved in practice) to ‘the overwhelming majority of experts’ “, you distort what he said. Russell did not say anything about “relaxing” his statement, otherwise he would have said so. I understand that it is convenient for your own point of view, but you shouldn’t use a Bertrand Russell quote to support it if it doesn’t. The rest of your argument goes along similar lines.
About Galileo: he was not an “an obscure scientist persecuted by an entrenched mainstream”. If you’re going to use him as an example, you should read a bit more about him. Galileo was NOT persecuted by the mainstream scientific establishment of his time. Galileo was a star all over Europe, exactly because he dared challenge the “consensus” about Aristotle, and by doing so opening the eyes of everyone.
Galileo could have accepted what “an overwhelming majority” of experts were saying about falling bodies. If he had, we would have had to wait for another “sceptic” to learn that “the overwhelming majority” were wrong.
Galileo was persecuted by the CHURCH, for very political reasons, because his thinking was seen as DANGEROUS, not scientifically, but socially. Also, he did not DEFY the establishment. He published what he thought was right, and when he did publish his “Dialogue on two world systems”, he thought he had the church approval. The Pope actually betrayed him, and let the extremists around him condemn Galileo.
My own version of scepticism is that it is the best way to make good science. I am myself a scientist with 25 years of practice. Whenever I read a paper, I read it with a highly skeptical eye. Whenever I make an experiment, and the results almost agree with the theory, I use the “almost” to dig further. Sometimes there is a lot in the “almost”. Sometimes the entire theory falls apart, or you find some unexpected effect that has important implications. So when I see results on climate that “mostly” agree that GHG cause GW, I say we have to look at why they only “mostly” agree, and not “totally”. Are we missing something important (to quote Rumsfeld, things that “we don’t know that we don’t know”), are we being misled by appearances, were we biased in the first place? The same with consensus. If an “overwhelming majority” agree, but there is a single voice out there saying something different, I will listen closely to THAT voice (listen, not necessarily believe). It seems to me that the “consensus” argument is very dangerous in that regard.
And yes, I agree with Feynman. Remember he led the enquiry on the first space shuttle disaster. What he found was that it’s the refusal to listen at contrarian points of view within NASA that was the main cause of the accident. There is a good lesson there.
Skepticism has nothing to do with what the experts, lots of them, or few of them, or all of them, agree or disagree about in a particular field.
Otherwise we fall back in arguing on the basis of authority, and if that were true, we would still be quoting Aristoteles like at the times of Galileo. Does anybody remember the troubles Nobel-prize-winnder Chandrasekhar had to go through before denting the “consensus” represented by Eddington (no less) at the beginning of the XX century?
Skepticism is about asking for evidence. And as wisely suggested by Carl Sagan, extraordinary claims (like, “Humans are changing the planet’s climate”) do need extraordinary evidence
Well, no. Feynmann showed that NASA managers had ignored actual failures happening repeatedly, and that they were ignoring the straightforward risk calculations done by the engineers.
Would a one percent risk of abrupt climate change be too much? I think any scientist will say it’s too much. Any politician or public relations mouth will say it’s insignificant risk.
NASA was lucky until they had to launch a schoolteacher — for a political window of opportunity — the first ever launch below freezing temperatures.
They went one step further outside the design envelope, into unknown risk levels.
Boom.
Feynman’s personal appendix, here, is very brief and very clear:
http://www.ralentz.com/old/space/feynman-report.html
Take a spacecraft — this planet — far outside its past performance envelope. Climate scientists are trying to understand the risks. The politicians and business PR people are obfuscating and denying any possible risk could exist so they can go on pushing outside the envelope.
Feynman said the engineering showed Shuttle risk was perhaps one percent — one failure in 100 flights, but
“Official management … claims to believe the probability of failure is a thousand times less…. demonstrating an almost incredible lack of communication between themselves and their working engineers.
…
“Let us make recommendations to ensure that NASA officials deal in a world of reality in understanding technological weaknesses and imperfections …. They must live in reality ….
“For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”
This is why the denial is so strong — because a one percent risk of losing the climate that made humans civilized is too much, and we’ve already taken the risk and are waiting on the outcome.
Since Feynman has lurked into this thread, here is a link to his commments on the space shuttle disaster : http://www.fotuva.org/feynman/challenger-appendix.html
And here is another quote from the same speech as above on “What is science”:
“When someone says, “Science teaches such and such,” he is using the word incorrectly. Science doesn’t teach anything; experience teaches it. If they say to you, “Science has shown such and such,” you might ask, “How does science show it? How did the scientists find out? How? What? Where?” It should not be “science has shown” but “this experiment, this effect, has shown.” And you have as much right as anyone else, upon hearing about the experiments–but be patient and listen to all the evidence–to judge whether a sensible conclusion has been arrived at. (…) I think we live in an unscientific age in which almost all the buffeting of communications and television–words, books, and so on–are unscientific. As a result, there is a considerable amount of intellectual tyranny in the name of science.”
My Summary below is posted here to encourage additional people to post their comments to my questions at RC’s subject: Naturally trendy.
Summary:
Comment 84. response in RC Naturally trendy reads: But statistics is only so much, and there is, as you say, inappropriate ways and appropriate ways to apply statistics. … rasmus]
Comment 91. in Naturally trendy reads: Do you think the procedure explained in 86. is an appropriate way to apply statistics … ?
Comment 93. in Naturally trendy reads: I do, because it integrates historical data with current conditions. I believe large short-term hydrologic events do make it into the probabilistic outlooks also. It’s not perfect, but I do think it is a reasonable product.
Comment in 94. in Naturally trendy reads: Although I understand that things can’t be perfect, I believe that professional hydrologists should try to adjust for inadequacies in modeling procedures and forecasts, which currently do not take account of the large amount of evidence showing that hydrologic climate warming has been happening in the Upper Midwest. …
Please go to RC’s Naturally trendy to post your comments. Naturally trendy is at: https://www.realclimate.org/index.php?p=228
Re #136
I think this is a very reasonable sentiment. Do you not find this extrordinary?:
http://en.wikipedia.org/wiki/Image:Carbon_Dioxide_400kyr.png
And this:
http://en.wikipedia.org/wiki/Image:2000_Year_Temperature_Comparison.png
Taken together with this:
http://en.wikipedia.org/wiki/Image:Global_Carbon_Emission_by_Type.png
Makes an extraordinary case. Not the whole story by far, but it is the extraordinary evidence demanded and leads to all the rest of the data and research that confirms many times over that something extraordinary is happening.
Now lets turn this same standard on those who remain unconvinced. Given the uncontroversial and well established physical principles of Greenhouse Theory, I believe it becomes an extraordinary claim to say that a 30% increase in CO2, the major persistent GHG, (please recall that H2O acts as a feedback and not as a primary forcing of temperatures), that an unprecedented in 650Kyr plus level of this important gas will not alter the climate. Where is the extraordinary evidence for this claim?
I think it is also an extraordinary claim to say that every major scientific institution dealing with climate, ocean or atmosphere is wrong, not impossible, but extraordinary. Michelson and Morley were certainly making a similar claim that all of their colleagues were wrong and there is no ether but they had extraordinary evidence! Where is the sceptic’s extraordinary evidence?
By all means, be sceptical, don’t take a stranger’s word for anything. But apply the same standard to all sides. Don’t give a free pass to authority figures, but don’t give one to that lone voice of doubt either, no matter how much romantic-underdog appeal that has.
RE #137
Feynman’s findings can be interpreted in a number of ways! My point is that management did not see the evidence for a large risk of failure because it went against their belief. They collectively convinced themselves that the shuttle was safe, so no evidence would have convinced them otherwise because they did not look at it. I see much of that attitude in the climate debate, on both sides of the issue.
My point is: it’s good to be a sceptic. Being a sceptic is the essence of being a scientist. Sceptic means: you don’t believe. Personnally, I have decided not to accept the argument that because there is a “consensus”, I should believe. This blog and others are useful to indicate which issues are contentious, but from there I usually try to go to the source and make up my own mind. I cannot even tell you at this point what my opinion is! It IS a very complex issue. There are a lot of data, and no, they don’t all point in the same direction. Just looking at a couple of graphs on Wikipedia is not enough! I’d say reading the whole of the IPCC TAR (not the summary) is a good start. There’s a lot of interesting stuff in there.
As for the contrarians, I don’t necessarily BELIEVE them, but at least I LISTEN to them. They also have a lot of interesting things to say.
> much of that attitude in the climate debate, on both sides
When people see “both sides” and “debate” I think they’re not watching the science — they’re watching the audience. It’s misdirected attention. Capturing that attention is politics and public relations work.
We’ve already given the climate a big input burning fossil fuels, among other natural inputs that we don’t know well — now, we’re like a bowler who’s already let go of the ball — leaning and twisting, in unconscious contortions that can’t influence the score that’ll come up when the rolling ball finally hits the pins.
The audience has “sides” — nature doesn’t. Nor do the scientists who’re trying to pull out an understanding of what nature’s been doing and what people are contributing to what nature will be doing next.
Maybe somewhere there is a fraud who’s faking scientific results — we saw the recent stem cell debacle. The real journals have to manage peer review, for the endeavor of science to work.
There are plenty of pretend “science” sources out there — not reviewed, full of cherry picked “facts” used for public relations, picking anything to push their agenda. There, you’ll find “sides” clearly enough.
If there’s been any miracle involved in civilization, I’d say the development of science has been that miracle. It didn’t happen over and over — for what, close to a hundred thousand years, through many different cultures from many different precursors, most cultures never got to the level of doing science. They’re forgotten. Ours did, somehow, and those who do science are the culture we all belong to, if only as audience members.
Keeping science working is not (except for a few USA school boards) a debatable question on which people take sides, in the civilized world, I think. I think there’s the culture that values science _whatever_the_results_ and we’re it.
We learn, or we don’t, to learn how nature works. Hard argument works in science — challenge, test, retest.
In this climate area there’s also a lot of money at risk, and a consequent huge fog of audience contention, sides, debates, flat out blatant lying (google “always been an ozone hole” for examples, or any other claim you care to test for repetition without research basis).
It’s not the scientists you’re watching when you see sides and debate outside the journals happening, it’s the audience you’re watching, and the public relations mouths yapping you’re hearing.
What worries me most is that there are still a lot of people who’d just as soon do away with science to avoid the awkward and inconvenient facts it keeps turning up.
Re #140
Coby
First of all thanks for recognizing that the whole “Follow what the scientists say” is a misleading route as far as reasoned skepticism is involved.
Let’s concentrate on the evidence then. And there comes another logical fallacy.
I cannot demonstrate, nor anybody can, what something does NOT do.
There are no known, and no unknown ways to show that “a 30% increase in CO2, […] that an unprecedented in 650Kyr plus level of this important gas will not alter the climate”
The ball remains strictly on the side of people interpreting the current data as evidence of a climate extraordinarily warming and because of human activity.
And all the more so as climate scientists were busy predicting a coming Ice Age just 30 years ago or so.
[Response: This is wrong, as we’ve pointed out before: see #144 below – William]
———-
With respect to the “extraordinary” warming of the planet, it’d be nice to be presented with incontrovertible effects: for example, a change in the monsoon patterns, a remarkable contraction of the dry areas in the Sahara, sustained hurricane seasons in the South Atlantic, etc. AFAIK so it’s always been a case instead of shrinking glaciers and potentially changing oceanic currents.
There may soon be no snowcap on top of Mount Kilimanjaro. But then, there was none 12,000 years ago either.
[Response: Source?]
Another example: is the Northwest Passage definitely usable by non-ice-breaking ships during the Northern Winter? And what is there to tell us when was the last time it had been so?
———-
Regarding the effect of human activity, given the fact that we cannot control at the moment the energies required for Planetary Engineering, the claim that we are changing the climate do remain extraordinary indeed.
[Response: No, not really. Just about everyone – even skeptics like Pat Michaels – accept that we are changing (warming) the climate. Michaels disputes the likely future warming; not that there is current warming. You are way out on a limb. – William]
What kind of “extraordinary evidence” would be required for that?
Surely not just computational models or simple long-term statistical correlations.
Both techniques deal with way too much uncertainties to be meaningful as “extraordinary evidence”. As reported on The Economist (recently converted to the Human-Made-Global-Warming cause):
“the most important uncertainty, though, is that caused by a lack of enough good-quality, long-term, internally consistent data. Even the industrialised parts of the world, Europe and North America and their adjacent seas, have been studied properly for only a century and a half. Too much climate science relies on drawing conclusions from patchy information”
[Response: The Economist isn’t a good source for climate science. See here for my take on that particular article – William]
—–
What kind of “extraordinary evidence” would be required then for a reasonably skeptical person to be convinced that humans are significantly changing the planet’s climate with carbon dioxide emissions?
I simply do not have an answer for that at the moment. Suggestions welcome, of course.
[Response: Errrm, well at least thats honest I suppose: you’re basically saying that nothing will convince you. The fact that the temperature is going up, as agreed by sfc, upper air and oceans; that models can reproduce the trend; and that this is unsual in the record we have is obviously not enough for you – William]
And so IMNSHO the “science of climate change” remains an interesting, debatable hypothesis, more akin in Physics to superstring theory (a long way from being demonstrated) than to Einstein’s relativity (overwhelmingly shown a robust theory)
Main consequence is of course that it all becomes a matter of debate, of policy, of politics. People (and scientists) must choose to believe (or not) in human-made-global-warming.
I am all for free speech and free thinking, so go ahead, and campaign to sequestrate CO2 and reduce the use of coal as fuel
But please don’t dress it up (yet) as “hard science”
> predicting an ice age
Bzzzt! Bogus. Bo-o-o-gus. Google is your friend here.
Google for that claim. First three hits: two PR-politics sites and, ta-da, RealClimate.
Look carefully for the difference between PR-politics and science, read footnotes:
Science Has Spoken: Global Warming Is a Myth
http://www.junkscience.com/news/robinson.htm
“… gradual planetary cooling, not warming, is next in the natural cycles driven by the sun. And records reveal cooling to be a far greater threat.” [yes, TODAY they say an ice age is coming]
http://www.friendsofscience.org/index.php?ide=4
RealClimate » The global cooling myth …
Every now and again, the myth that “we shouldn’t believe global warming predictions
now, because in the 1970’s they were predicting an ice age and/or …
https://www.realclimate.org/index.php?p=94
#143:
This argument, IMO, isn’t quite right.
It is quite testable (sciency stuff) to expect that increasing CO2 in the atmosphere should warm the planet (sure, there will be cooling in places).
Why? Physical principles realized over a century ago by some Swedish chemist guy allow us to make this hypothesis. The evidence backs the hypothesis. In fact, there is sufficient evidence to call it a theory, which arguably makes it a hard science (physics – a hard science (it was really hard for me) – is the basic underpinning of meteorology, e.g.).
Additionally, physical principles do not state that increasing CO2 will, say, cool the planet. This would violate physics. So, in this context, it would still be easily testable to expect that increasing CO2 in the atmosphere should decrease the planet’s temperature [please, no replies about meaninglessness of avg T]. Simple enough: where is the skeptic model that displays results confirming this hypothesis? Nowhere. Not one.
There is no debate about competing scientific theories. There is no debate about differing results of modeling runs. There is no debate about evidence stating the planet is cooling in the elevated CO2 regime [higher than at any time in the past ~650K yr]. There is no debate about differing atmospheric CO2 measurements.
Of course, the devil is in the details and the debate is about how much of the current warming is caused by man, and how much is part of a natural cycle. Period. The problem is that little bit about CO2 in the atmosphere, and that negates the tout that it’s all natural cycle. Why? Well, where is the skeptic model/result/evidence/film/.ppt/rune cast result/astrological chart that shows the elevated CO2 has played no part in the rise? Nowhere. Not one. So, we’re back to the details and amount of attribution [the skeptics/denialists/contrascientists want zero attribution], and the debate is about teasing out all the confusing signals from the biosphere, and the universal issue about having enough data.
The biosphere will react when the planet warms. And the increased plant growth in temperate latitudes may serve to sequester CO2. The ocean may absorb some heat (evidence shows it has). Tundra will melt, releasing CH4 (evidence shows it has). Etc.
There is plenty of stuff for quibblers to use to proudly state it all becomes a matter of debate, but to my mind this is a consequence of Google returning information, not wisdom.
Best,
D
No worries. Now at the risk of turning agreement back into disagreement, I really want to emphasis that I think that the kind of scepticism that you and I do agree is a good thing is not appropriate for anyone who does not study the issue. People who do not know the basics of climate theory and where the state of current research is and what has already been thought of and why it has been ruled out, and yet still insist that the case as a whole is unconvincing are not being sceptical, they are being denialists.
[about sceptics showing CO2 does not raise temps.]
I understand where this comes from, but you have taken it out of its strict logical context and slightly twisted it as well. You can’t prove a NOT(X) etc. But clearly I can demonstrate that action X does not have effect Y. I can drop a rubber ball on a piece of cement repeatedly and thereby demonstrate that this action does NOT shatter the concrete. You should be able to show through laws of physics and also via lab experiments that increasing CO2 in an atmospheric mix of gasses does not cause greater absorbtion of infrared radiation. It has certainly been demonstrated that it does.
Of course the geophysical reality is much more complicated. That’s why we must look at history through the grubby lenses of proxy data and run models and observe everything we can think of.
[Now before you list a “third” logical fallacy of mine, I would like to say for the record that you have not got me one one yet]
I don’t have much to add to the rest of your comments that I haven’t already said or others have already pointed out except that you are quite simply setting a standard that can in fact never be met. What else is there besides models, radiative physics, statistical correlations and observations of strange changes? (I am kind of intrigued that you are not impressed by melting ice, rising sea levels, rising temperatures, slowing ocean currents, warming ocean waters, all kinds of changes in flora and fauna but you mention “a change in the monsoon patterns” and “a remarkable contraction of the dry areas in the Sahara” as something “incontravertible”!)
Ignoring that inconsistency, I think the kind of proof you are otherwise demanding requires multiple copies of our planet and some rather large timemachines – it ain’t ever gonna happen.
So your answer is damn the torpedos, full speed ahead? That’s one hell of a gamble with something unique, priceless and not yours.
Here are a couple of examples, I think, of people being good skeptics.
Many will recall last year the sudden spread of the assertion that 90 percent of the world’s glaciers are actually growing.
One person checked, it’s bogus (although “90%” is still being repeated as a fact).
Skepticism at work, good examples:
George Monbiot » Junk Science
By George Monbiot. Published in the Guardian 10th May 2005 …
[Claim of growth of] 555 of all the 625 glaciers under observation by the World Glacier Monitoring Service … So last week I telephoned the World Glacier Monitoring Service and read out Bellamyâ��s letter.
……
http://www.monbiot.com/archives/2005/05/10/junk-science/
Effect Measure: Bad typing and bad science
Bellamy’s cited source for the glacier “facts” was the World Glacier Monitoring
Service. Monbiot phoned the Service …
http://effectmeasure.blogspot.com/2005/05/bad-typing-and-bad-science.html
As a skeptic, I would like to know:
1. What is the lag time between an increase in CO2 in the atmopshere and a rise in global temperature?
2. If “we” (You better count the several billion people in Asia here, not just a few hundred million people in North America) stabilized the amount of CO2 in the atmosphere today, how much more warming would the Earth experience?
3. Since the North Pole and Greenland are melting right now, according to the meanstream opinion, how will limiting future increases in CO2 emissions prevent climate catastrophe? We already have severe climate change (drought, flood, hurricane, unnaturally warm weather, permafrost melting, etc.), according to mainstream opinion.
4. Is there any scenario wherein atmospheric CO2 will be reduced in the next 50 years? If we accept the fact that our current warming trend, with melting of the arctic and Greenland leading to massive floods, is due to the current level of CO2, why bother with modest attempts at CO2 emission reduction?
It is obvious that the Kyoto proponents don’t believe that we are experiencing severe climate change due to the current level of CO2. If they did, their support of such modest reductions embodied in the Kyoto treaty just wouldn’t make any sense. So, if they are skeptics, can you blame me?
Hopefully you will get a more qualified respondent, but my understanding is that there are in fact still several decades of warming “in the pipeline” so to speak. This is due mostly to the time it takes the ocean temperature to rise and a new equilibrium to establish after the imposition of an energy imbalance.
I think I have read that another 1oC or so is pretty inevitable.
Uh..by stopping the melting..? Why is that hard to understand?
Obviously we want to slow and eventually stop the changes that cause these negative consequences. All these rhetorical questions seem to suggest there is only “good” and “bad” and no degrees in between. The point of action now is to stop a bad situation from getting worse. What is the point of this “my hand already hurts why should I remove it from the stove” reasoning?
Your question about scenarios seems to indicate you don’t understand what a scenario is. It is simply an imagined future trend of GHG emissions, so yes of course there is such a scenario where CO2 is reduced in the coming decades: the world stops all fossil fuel burning emissions within one or two decades. Such a scenario was not presented in the IPCC report because it clearly is extremely unlikely.
Kyoto is a political issue. The discussion of scepticism on this blog is about the science.
It is absolutely pointless to discuss Kyoto or any mitigation action proposals with someone who has not yet acknowledged that climate change is real and human caused and action of some kind is necessary. When someone raises the spectre of Kyoto’s shortcomings in a discussion of climate science it can only serve to obfuscate any serious discussion.
re 148, 149
I recommend:
Hansen, J. 2005. Is There Still Time to Avoid “Dangerous Anthropogenic Interference” with Global Climate? A Tribute to Charles David Keeling (5.5 MB PDF). Presentation given Dec. 6, 2005, at the American Geophysical Union, San Francisco. 50 p
http://www.giss.nasa.gov/~jhansen/keeling/keeling_talk_and_slides.pdf
Also see:
http://groups.yahoo.com/group/ClimateArchiveDiscussion/message/592