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Climate Change and the Integrity of Science: a letter to Science

Posted on 8 May 2010 by John Cook

A letter Climate Change and the Integrity of Science has been published in the journal Science. It's written by 255 members of the US National Academy of Sciences, including 11 Nobel laureates (here's the complete list plus their university affiliations). I recommend reading the entire letter but here is an excerpt:

There is always some uncertainty associated with scientific conclusions; science never absolutely proves anything. When someone says that society should wait until scientists are absolutely certain before taking any action, it is the same as saying society should never take action. For a problem as potentially catastrophic as climate change, taking no action poses a dangerous risk for our planet...

... The Intergovernmental Panel on Climate Change (IPCC) and other scientific assessments of climate change, which involve thousands of scientists producing massive and comprehensive reports, have, quite expectedly and normally, made some mistakes. When errors are pointed out, they are corrected. But there is nothing remotely identified in the recent events that changes the fundamental conclusions about climate change:
  1. The planet is warming due to increased concentrations of heat-trapping gases in our atmosphere. A snowy winter in Washington does not alter this fact.
  2. Most of the increase in the concentration of these gases over the last century is due to human activities, especially the burning of fossil fuels and deforestation.
  3. Natural causes always play a role in changing Earth's climate, but are now being overwhelmed by human-induced changes.
  4. Warming the planet will cause many other climatic patterns to change at speeds unprecedented in modern times, including increasing rates of sea-level rise and alterations in the hydrologic cycle. Rising concentrations of carbon dioxide are making the oceans more acidic.
  5. The combination of these complex climate changes threatens coastal communities and cities, our food and water supplies, marine and freshwater ecosystems, forests, high mountain environments, and far more.
Much more can be, and has been, said by the world's scientific societies, national academies, and individuals, but these conclusions should be enough to indicate why scientists are concerned about what future generations will face from business-as-usual practices. We urge our policy-makers and the public to move forward immediately to address the causes of climate change, including the un restrained burning of fossil fuels.

The scientists are the members of the NAS most familiar with climate science, as explained by lead signer Peter Gleick:

It is hard to get 255 members of the U.S. National Academy of Sciences to agree on pretty much anything, making the import of this letter even more substantial. Moreover, only a small fraction of National Academy members were asked to sign (the signatories are all members of the U.S. National Academy of Sciences but were not speaking on its behalf). Because of a desire to produce a statement quickly, the coordinators of the letter focused on those sections of the NAS most familiar with climate science and the ongoing debate. But the NAS (and Academies of Sciences and other professional scientific societies from dozens of other nations) has previously published a long set of assessments and reviews of the science of climate change, which support the conclusions laid out in the Science essay.

Lastly, here is a link to the National Academy of Science's Policy advice, based on science, to guide the nation's response to climate change.

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Comments 51 to 100 out of 239:

  1. skepticstudent, for an even more detailed exposition of the fact that global temperatures have not decreased since 2000, see Tamino's "Hottest Year". For more fundamental evidence, see the Skeptical Science post It’s cooling.
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  2. Sooner or later someone is going to point out that the NAS has 2100 members and 350 foreign associates and claim that it's a poor representation of numbers. However the membership is spread over 31 disciplinary Sections and therefore not all members would be able to speak to the subject of climate change. See here. For clarification that would be 6C and not 6F would it Marcus. Regardless of which it is it refers to "global" temperature. 6F humanity might be able to cope, but at 6C -- well -- kiss it goodbye.
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  3. skepticstudent wrote "So could it be that it is not so catastrophic." The term "catastrophic" is a strawman. For concrete, detailed points about the effects of global climate change, see It’s not bad, and also CO2 is not a pollutant, and oh, yeah, Animals and plants can adapt to global warming.
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  4. Yes it was global average temperatures of roughly 6 degrees C above the 1961-1990 mean, not F (I'm an Australian, so Fahrenheit is not a concept I'm familiar with ;)). Also note that these temperatures occurred during a period when the sun was 10% cooler than today, & at a time when the continents were in very different positions to what they are today. That said, there is a *reason* why agriculture first flourished in a relatively narrow climate band of the planet-its because rainfall & temperatures were *just right* for agriculture to exist-South or North of this zone Agriculture largely failed to take hold. Now technology has certainly helped agriculture to survive in slightly more hostile environments, but its nonsense to believe that agriculture could cope with a further 0.6 to 1 degree C increase in average temperatures.
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  5. #13 ominlogos "Lest we forget: it took 80 years for the evidence of pre-Cambrian fauna to be accepted. [/quote] That's in significant part because the evidence was ambiguous, until definitive detailed fossils in non-sedimentatious rock were identified. You're also talking about a period of 1860s to 1950s and for at least half of that, deep-time paleontology was in a state of infancy. That very solid evidence is required to overturn a well-accepted model, is not something to fault science for. [quote]Ironically, Nature magazine rejected one of the most compelling proofs, as it was presented by a "nobody", only to change their mind when finally a renowned scientist bothered to check things out.[/quote] So, in fact, the paper by the 'nobody' grad student Misra, which challenged the dominant paradigm, *was* indeed published ,in Nature, after extensive peer review. Thanks for reminding us. Now remind us that crap papers sometimes get published after peer review too.
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  6. Skepticstudent, You made a few references to temperatures in 2008, as well as temperatures in Alaska specifically. If you agree that short term regional data is not the same as long term global trends, how are these references relevant? Why is temperature in 2008 relevant to the question of long term global warming? Please explain your reasoning and specifically how this information undermines AGW. Yes you also made the claim that global temperatures have gone down in the past 10-20 years, but you neglected to provide your sources for this information. Please provide relevant data to back your claim.
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  7. #46 johnd, there are indeed paired belts of uplift and subsidence, and the uplift and subsidence are mostly due to recoverable elastic deformation, and are cyclical. To a first approximation, the areas that subside between earthquakes uplift during the earthquake, and vice versa. In general, there is much larger horizontal motions as well. The figures on this page at the Geological Survey of Canada illustrate it pretty well. In Alaska, the area that subsides today is mostly offshore (including in Prince William Sound), and this area uplifted greatly back in the 1964 earthquake (still the 2nd biggest ever recorded). Farther inland, we observe uplift, and an area that subsided significantly. The rapid vertical motions are the main reason that none of the Alaska tide gauges have been used in estimates of sea level change, but that is likely to change within a few years because we can now measure the vertical motions precisely enough calibrate the tide gauges, at least in the places where the tide gauge records are linear with time.
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  8. Marcus at 12:54 PM just to put a different spin on your statement, "I find it ludicrous that you can pump *millions of years* worth of geo-sequestered CO2 into the atmosphere, in the space of less than 200 years". In those millions of years about 10,000 billion tonnes of carbon were locked up as fossil fuels, plus about 40,000 billion tonnes as sediments deep under the ocean (as limestone?) We are releasing about 6.5 billion tonnes of carbon annually through burning fossil fuels. By comparison deforestation releases perhaps 2 billion tonnes of carbon per year. If that deforestation could be halted and reversed, then not only would the release of the carbon be halted but the additional plant growth would go a long way to offsetting that released by the fossil fuels.
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  9. In truth, (since the times of James Watt), thanks to science and engineering the current levels of fossil fuel output and combustion could never have been achieved. Ironically, the public is being asked to place its trust in scientists for a "problem" labeled "anthropogenic", (as if to blame people as opposed to technology).
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  10. John, I recall your earlier post: Thursday, 11 March, 2010 Guest post: scrutinising the 31,000 scientists in the OISM Petition Project in which you very rightly questioned the credentials of the signatories. Of course, the present signatories include scientists of great repute - no doubt, all seriously intelligent, well read, and committed to a better outcome for our planet. The letter is well-written and thoughtful. A significant number of signatories however (based on reported academic affiliations) would lack the expertise to comment as climate scientists. As such, many really ought not to have signed the letter. They are entitled to barrack for their views. However, they should do so as private individuals and not under the umbrella of the National Academy of Sciences. Otherwise, I fear we may be applying a double standard no matter how distinguished the signatories. I don't want to nitpick. However, scientific integrity requires that experts carefully observe the boundaries of their expertise.
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  11. The (non-trivial bits of) the commentary above raise an interesting question. We (anecdotally)appear to be in a period of increased seismic activity. Could that be due, in part to the earth shifting from the loss of ice mass? It seems far-fetched, but I am very far from up to speed about the loss of ice volume.
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  12. I see that there are no Canadian researchers on that list. Canadian climate denial is centred in Calgary. The latest tenor is that CO2 has essentially no effect. A CO2 denier talk has made it into next week's GeoCanada 2010: http://www.geocanada2010.ca/program/program-schedule/tuesday/pm-2/climate-change-through-time.html We are running a small but fine blog taking on these deniers with something they do not have: humour. Check it out and pass us on to their friends and colleagues - and join us: http://friendsofginandtonic.org/page1/page1.html
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  13. chriscanaris> I feel that the problems with the OISM petition is different. The present letter explicitely states that is not under the umbrella of the National Academy, but that the 255 signatories are among its (approximately two thousand) members. That's a pretty good turnout. I don't see any problems in the fact that these people are not specializing in climate research, since they are not pretending that they are. On the contrary, I read the letter as support and as a declaration of trust from a large section of the general science community (as represented by the NAS) to climate science.
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  14. @ skepticstudent "Einstein was laughed out of numerous houses of academia because he had not proven his theory of relativity. He went from one to another with the same results." This is untrue. Einstein was unable to secure academic employment following graduation. But his papers of 1905, including 'On the Electrodynamics of Moving Bodies' (where Special Relativity is set out) were taken very seriously by the scientific world, in spite of their radical nature. Seven months after publication Einstein wrote: "My papers are meeting with much acknowledgement and are giving rise to further investigations." The world renowned Max Planck, among others, was an immediate supporter. If you are going to reference great men in your arguments, it might help to get your facts right, instead of relying on myth and hearsay.
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  15. Skepticstudent, RE #1: How do snowy winters indicate declining temperature? Increased precipitation in Greenland (for example) goes hand in hand with greater moisture, which is probably caused by warming further away. If your average temperature is below 0C, then warming may well increase snowfall. After all, Antarctica is the coldest place on the planet and also the world's largest desert. The ACC causes part of this but climate models expect warming to lead to increased snowfall there so there is a link. Your argument also disagrees with measurements of decreasing NH snow cover averaged over the year. And it disagrees with surface thermometers, radiosondes and MSUs that all show warming.
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  16. Marcel Bökstedt @ 63 'The present letter explicitely states that is not under the umbrella of the National Academy' Fair point - I missed the footnote. But then again, it was but a footnote. The Devil is in the detail - the footnote is easily overlooked. Realistically, my trust in Climate Science as presently conducted is of marginal relevance to the issue under discussion. Consequently, I would not have signed the letter even if I moved in equally august circles. Significantly, 90% of the membership of the NAS did not sign. Five hypotheses suggest themselves. a) Nobody approached them, b) They don't believe in AGW, c) They don't trust the climate scientists (not the same as not believing in AGW), d) They don't feel they have the requisite expertise, e) Any combination of the above. As regards trust in scientific integrity, I can only speak of my own field - psychiatry - where I have encountered some seriously shonky practice (and thankfully many fine clinicians and scientists). I suspect most honest scientists would say much the same about their respective fields. I really don't want to sound like curmudgeonly contrarian but doctorates, professorships, and memberships of prestigious bodies are no guarantees of virtue.
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  17. "Marcus you want to recheck your facts. Even the NASA GISS facts don't dispute that the temperatures have been declining on a global basis since the year 2000. Agree with me or not the facts are there. so we'll just let this one go and agree to disagree." I'm going to disagree with you on this one. The least squares linear regression fit to UAH satellite data from Jan '00 to April '10 is +0.013C/yr. In HadCRUT3 it is +0.006C/yr. In RSS satellite it is +0.002C. In GISTemp it is also positive. Thanks to Ian Forrester, you can play around on the site he gave you or just google the data to play for yourself. Ofc, we already know that short term measurements (1-2 decades or less, say) are probably not telling you much about climate, and Tamino has a more rigorous post.
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  18. Here's another Wood For Trees set to play around with (CO2 at top). Wood For Trees ten year temperature trends offset every five years since 1880 And temperature with solar, sea ice and CO2
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  19. Chris Canaris writes: Significantly, 90% of the membership of the NAS did not sign. Five hypotheses suggest themselves. a) Nobody approached them, b) They don't believe in AGW, c) They don't trust the climate scientists (not the same as not believing in AGW), d) They don't feel they have the requisite expertise, e) Any combination of the above. Chris, this is addressed in the original post at the top of this thread. The organizers only circulated the letter within those sections of the NAS most closely related to climate science: "Moreover, only a small fraction of National Academy members were asked to sign (the signatories are all members of the U.S. National Academy of Sciences but were not speaking on its behalf). Because of a desire to produce a statement quickly, the coordinators of the letter focused on those sections of the NAS most familiar with climate science and the ongoing debate."
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  20. skepticstudent writes above: As I mentioned yesterday in a post that needs to be re-written [...] 2008 had the 3rd coldest winter since thermometers were created in 1775. Your repeated posting of vague and unsourced claims makes it very hard to have any kind of useful discussion. In that earlier comment, you said "in 2008 the temperatures were the third coldest since thermometers were invented in 1775" -- nothing about "winter". I replied here, pointing out that 2008 was nowhere near "3rd coldest year since 1775" -- in fact, it was the 10th warmest year since 1880. Every year since 2001 has been in the top 10! Now you are saying that "winter 2008" was the third coldest since 1775. That's a little bit less wrong, but not much (actually, it's the 106th coldest winter since 1880). Please try to be very precise in your claims (if you're talking about temperature trends in certain months vs the whole year, or in certain places vs the whole globe, make that clear) and please try to provide a link or a source. Thanks.
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  21. The most prominent developing meme so far in the debates I've been involved with concerning this letter: Only 10.5% (or 12.75% excluding non-US NAS members) signed, so that means almost 90% of NAS members disagree with it. My response: This is explained by the lead signatory. Also, the Oregon Petition and the APS Petition didn't even reach whole number percentages, not even one half of one percent, but this letter got to double digits. This letter's kung fu is stronger than the denialists' kung fu.
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  22. Maybe it's just me, but I for one would be perfectly happy if we left the "kung fu" thing in the other thread. At least I sure hope this isn't some new SkS tradition that we're all going to have to adhere to!
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  23. It seems to me that many who take a "sceptical" view of this letter are missing the point. The letter is concerned with "Climate Change and the Integrity of Science". As has been pointed out to scepticalstudent and others, issues of climate change are well addressed elsewhere on this site. We should address the Integrity of Science here. The key sentences are: Many recent assaults on climate science and, more disturbingly, on climate scientists by climate change deniers are typically driven by special interests or dogma, not by an honest effort to provide an alternative theory that credibly satisfies the evidence. We also call for an end to McCarthy-like threats of criminal prosecution against our colleagues based on innuendo and guilt by association, the harassment of scientists by politicians seeking distractions to avoid taking action, and the outright lies being spread about them. I view this letter as a defence of the way scientists "do" science, rather than solely a defence of climate change. Anyone who takes issue with it should be willing to demonstrate how the integrity of science is upheld by "sceptics"/ deniers, who hold themselves to lower standards.
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  24. @ tobyjoyce. Yes, this letter does highlight a recent, disturbing trend in the so-called "debate" on global warming. Having all but *failed* to prove-even remotely-that either global warming isn't occurring and/or that human beings aren't the cause, they've now turned to digging up dirt against climate scientists & trying to very publicly accuse them of a range of wrong-doings. Given that at least one skeptic organization was caught out privately admitting that they didn't believe their own skepticism, then I think such ad hominem attacks are a case of "those in glass houses...." I mean, if we were to do thorough background checks of even half the so-called skeptics out there, I wonder just how much dirty laundry we'd discover. Just as well that climate scientists choose to fight this issue on SCIENCE rather than PERSONALITIES!
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  25. Marcus: you mentioned a skeptical organisation that didn't believe its own stuff. Where is your evidence for this? (I've always wanted to know whether the skeptics spouting the clear rubbish memes genuinely believed it or not!)
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  26. SkepticStudent:
    I think I have a pretty good grasp on temperatures and snow fall since I've lived in the Pacific Northwest for over 30 years and I have lived in Alaska.
    Sorry, SS, you're doing it wrong. Your personal experience doesn't make you an expert. I'm afraid you've to a long way to go before you'll be taken seriously here. Please read about the Dunning-Kruger effect. Then start educating yourself. Anyone can become an expert, if they're willing to make the effort. First, though, you need to realize that it's not enough just to be smart, you have to actually know something about the subject. If you're going to challenge the AGW consensus, you'll get respect only if you've put the time in, and not skipped any part of the process. That means starting with introductory material and working your way up. That's the only way you'll acquire the theoretical framework needed to interpret the massive amount of empirical data, from multiple independent sources, that the AGW consensus draws on. To even know of the existence of the data requires reading all the historic and current peer-reviewed literature. Interpreting the data requires a thorough knowledge of statistics, and you'll want to conduct your own experiments, and develop and test your own models. Very few people can do all that on their own. For most of us, the only practical route is an extended apprenticeship: obtaining undergraduate and graduate degrees, and doing original research under an established advisor. Throughout, you'll have to interact regularly with the community of professional peers that have been working on this for decades: discussing it informally, in person, by phone and by email (perhaps more cautiously than Phil Jones did); and formally, by presenting your ideas at the same conferences and publishing articles in the same journals they do, which unavoidably entails exposing yourself to their unsparing criticism 8^(! Are you up to it, SS? If not, then don't be surprised if you're met with ridicule and dismissal here.
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  27. Ned @ 69 'The organizers only circulated the letter within those sections of the NAS most closely related to climate science: ...Because of a desire to produce a statement quickly, the coordinators of the letter focused on those sections of the NAS most familiar with climate science and the ongoing debate.' Fair point - I should read things more carefully. Hypothesis (a) - that no one approached the 90% gets some traction. Many signatories, however, come from settings such as the Harvard Medical School and other medical institutes. Some are chemists and biochemists. Others are biologists and social scientists. Prima facie, their closeness to climate science seems questionable. So why were they asked to sign? This generates hypothesis (f): the organisers quickly worked up a list of people within the NAS they knew would be sympathetic and asked them to sign. Such a group would be very easy to compile - many would know one another through membership of political parties, lobby groups, or even family ties. I have no quarrel with them doing this - it's the way of the world. However, including non-climate scientists in your line up is self-defeating and unfortunately risks parallels with the OISM petition. This is especially so if you specifically claim you only approached a small percentage of the membership ostensibly because of their climate links.
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  28. chriscanaris says: "However, including non-climate scientists in your line up is self-defeating and unfortunately risks parallels with the OISM petition. This is especially so if you specifically claim you only approached a small percentage of the membership ostensibly because of their climate links." That's something of a straw man, don't you think? Even when it's clear that the letter is inclined towards climate science, yet refers to all of science as per the very first sentence of the letter, I think we can conclude that the choice of members to approach was a highly logical one. I'll take a gentleman's bet with you: Two months from now half of the NAS membership will have signed a similar letter.
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  29. Marcus #74, The efforts by the Attorneys-General of Virginia & Texas to pursue scientists like Michael Mann over state grant money they received is especially disturbing. it opens up vistas of scientists being asked to return funds when a promising line of enquiry turns out to be a dead end. Or for following political heretical investigations into stem cells, or even evolution. Steven McIntrye at Climate Audit has come out in opposition to this, and due credit to him for that. But it has been pointed out that he was one of the people who created the poisonous atmosphere which makes ambitious politicians seek to be media stars. Another disturbing trend is to equate media discussion with science. If Climate Audit or WUWT publish (for example) a reasonably good post, it gets all sorts of "yeahs" and "Right Ons" as if it is another convincing refutation. The readers do not seem to realise that such assertions have to be peer-reviewed or presented at conferences or seminars before they can be accepted as "proof" or tested science. Now, there have been really great posts as sites like this one, and Taminos (which I admire because I am a statistician) but I think this is science-popularization or science-for-the-layman, which is a respected part of science. The most successful science book of all time was a work of popularization "The Origin of Species" which was really a general discussion of Evolution that put the idea "out there" for the first time. The hard-core science came afterwards. On the denialists, you get someone like Joe Bastardi appearing on TV repeating stuff he read from WUWT, and treating it as if it was "real science" and not a set of speculations or untested assertions. This kind of stuff gets repeated on TV and print media all the time. "IPCC Wrong Again!", and the corrections somehow never get published. As has been said before, denialism is treated with a lower standard. Guess what I am saying is that there is a dangerous blurring of boundaries in which science may tend to be governed by what is "hot or not" in the media, and cease being an ideal of free inquiry. To an extent, this has always been the case, but with the billions at stake in energy research, climate science seems to be the latest and worst case of media intimidation of scientists. Polticians run scared of media exposure, and are always loath to be identified with media targets.
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  30. @Ned (#72)... Don't underestimate the power of a good humorous metaphor. Science has a way of coming off like dry wheat toast. Anything you can do to sweeten science up goes a long way toward melting the heart of the broader non-scientific audience. Deniers aside, we already know that the vast majority of working scientists believe that AGW is a real concern. The task before scientists today is effectively communicating those concerns, which is what this thread is about. A strong, effective use of language is essential to communicating that message.
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  31. From #59 RSVP 16:28 8th May. "Ironically, the public is being asked to place its trust in scientists for a 'problem' labeled 'anthropogenic', (as if to blame people as opposed to technology)." Technology emerges and develops independent of people?
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  32. Mal Adapted at 23:29 PM, how many contributors here actually meet your criteria of being an expert or having undergone an extended apprenticeship. Any? My impression is that most have merely hitched their horse to one cart or the other and have placed their faith, perhaps blindly at times, in those on board the cart who have or claim to have relevant expertise. As you also mention, a thorough knowledge of statistics is necessary making it seem that understanding climate change is more about number crunching than understanding the basic principles involved something which I think is also reflected here. That is the impression I get from the scientific debate itself. Many scientists, (how many are merely statisticians?) presenting and supporting the AGW hypothesis seem to have expertise on interpreting data and statistics, whilst those sceptical of it question and examine, not necessarily the data and statistics, but some of the basic principles that remain unresolved and not adequately understood or quantified as yet. It also may be a folly to assume the Dunning-Kruger effect only exists at one end of the spectrum, (or on one side of the debate) and not throughout, even at times amongst those who consider themselves the elite of their profession.
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  33. 81 shdwsnlite "Technology emerges and develops independent of people?" Anthropogenic means "caused" by humans. Technically, this is a misnomer, in that it implies that if you are a human, you are causing this problem. In reality, it is use of machinery that is supposedly causing global warming. Machines and fuels that are the result of applied science.
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  34. johnd @ 82, The point is skepticstudent claimed his personal experience granted him some sort of special knowledge on the topic. Yes, the majority of posters here do not have relevant expertise, that is why the site puts a lot of emphasis on references to peer-reviewed research performed by experts in the field. If skeptics on this site are arguing in good faith, they should be able to provide the same. Skepticstudent has so far offered nothing but bald assertions. The majority of scientists researching AGW relevant topics are climate scientists, not statisticians. Statistics is key to any scientific discipline that evaluates data. Understanding what the data tells us is key to understanding the basic principles of how the world works. Empirical data trumps purely logical arguments every time, this is central to the scientific method. Famous example: Einstein never really embraced quantum mechanics. He even came up with some compelling thought experiments that seemed to undermine the basic principles of quantum theory. In the end, the empirical data (which was statistical in nature) proved Einstein wrong, and the basic conclusions of quantum mechanics are now considered scientific fact.
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  35. #66 chriscanaris "I really don't want to sound like curmudgeonly contrarian but doctorates, professorships, and memberships of prestigious bodies are no guarantees of virtue." Of course this is true, but it's also true that we normally accept the consensus view of experts on any number of questions, from medicine to astrophysics, without worrying ourselves about their "virtue." What's interesting is not that one can cast casual aspersions on any group of experts, but that some people seem to have a psychological or political need to do so in regards to AGW, even though they'd accept the experts' view on other issues about which they know just as little. It seems to me that one should either doubt all consensus, across the board, or give climatologists the same presumption of honesty and competence that one normally extends to other scientists.
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  36. Johnd,
    how many contributors here actually meet your criteria of being an expert or having undergone an extended apprenticeship.
    The scientific consensus on AGW has been reached by the professionals who do meet the criteria. Before I found an easier way to make a living, I followed the process far enough to see for myself how scientific consensus is established. The other contributors here can speak for themselves. As for whether D-K only exists "at one end of the spectrum", the salient feature of the D-K effect is that it's asymmetrical. Darwin formulated it long before it was named: "ignorance more frequently begets confidence than does knowledge."
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  37. RSVP:
    In reality, it is use of machinery that is supposedly causing global warming. Machines and fuels that are the result of applied science.
    Bill Ruddiman thinks humans began affecting climate when they started using fire to modify landscapes, and accelerated the process by converting large areas of primary vegetation for farming. Of course, the combustion of vast amounts of fossil reduced carbon in the last couple of centuries has produced a hockey stick effect.
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  38. Monckhausen @ 62 Funny site that. But Dave Schindler is on the list and he is definitely Canadian -- proudly so. He is also in Calgary, so you need to be careful on two points. I wouldn't get the guy angry! ChrisCanaris @77. The evidence for climate change is derived from both climate science and the responses of biological/ecological/hydrological systems to that change. Social Scientists and some economists are involved in models of land-use, energy use projections and archeological evidence for climate change. One of the most convincing aspects of AGW has been the consistency of results across many distinct fields of inquiry. Indeed understanding prospects for future climate change (and causes of past change) is impossible without interdisciplinary interaction as humans, the hydrological sphere, the climate and ecological systems interact through the climate. The key difference between this letter and the OISM petition is that these 255 people are at the very top of the academic ladder. They may not represent the NAS directly, but they definitely represent the best science has to offer and they are in tune with the consensus. You simply can't say those about the OISM signatories.
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  39. In the previous post I meant humans etc interact through the carbon cycle. About this letter. I know a number of the signatories, I'm proud to say. One has his office next to mine; one was my thesis advisor, probably the scientist with the most integrity that I ever have known. The letter makes a strong point by ranking climate science with evolution and the big bang - believe me, that means something coming from the evolutionary biologists on this list. It's a call to arms really. This letter is definitely motivated by the sense that the way the climate debate is playing out in the media, the internet and now in the political/legal spheres was becoming a threat to the very way science is conducted. Science needs to have free and open (and that means often messy) debate. However, there is a clear sense that a chill is descending because anything you say could be misinterpreted, taken out of context, twisted in the blogosphere -- or it may be subject to political or legal action for simply not adhering to a position. I feel it even in the classroom. What I wonder is how we as scientists can communicate better when it seems the mechanisms we have typically used to popularize real science have been coopted by a much more efficient denial campaign, or crippled by the breakdown of traditional media with trained science journalists. Do we need a new sort of structure for communicating science? What would that look like? BTW This site is absolutely fantastic, John. Very level headed and clear. I point students to it all the time. You're a source of hope to me and others! Maybe it makes my worries moot.
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  40. Mal Adapted at 03:03 AM, Darwin was wise enough to qualify his observation with "more frequently" than "always" which is how it is sometimes perceived.
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  41. Mal Adapted at 03:11 AM, WHRC calculated that between 1850 and 2000, 155 billion tonnes of carbon was released to the atmosphere from changes to land use. Given there is presently about 750 billion tonnes of carbon in the atmosphere, irrespective of what view anyone might take on the residency time, 155 billion tonnes is a significant amount, and I'm not sure that it is being given the necessary attention with all the focus there is on the combustion of fossil fuels.
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  42. Johnd,
    Darwin was wise enough to qualify his observation with "more frequently" than "always" which is how it is sometimes perceived.
    Fair enough. People who can acknowledge their ignorance can easily become less ignorant. It's those who think they're experts because they read something on WUWT, that are dragging the rest of us down.
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  43. johnd @ 82 I think you will find that quite a lot of posters here have put quite a lot of effort into understanding the science on both sides of the argument, and have not just "hitched their horses", but have formed a rational opinion for themselves. Your comment on "mere statisticians" is off-the mark (although it may be that being a "mere statistician" myself I am perhaps biased [sic]). A good statistician gets to grips with the data generating process (in this case the basics of climate physics); for a good statistician it is not about the number crunching. If you think "skeptics" are more concerned with basic physics than number crunching, try Craig Loehle's recent paper in Atmospheric Environment, where he asserts an exponential model for the growth of CO2 is no better than a saturating or polynomial model, purely on the basis that they give similarly good fits to the calibration data (the Keeling curve). Sadly this neglects the fact that there are data that exist pre-dating the Keeling curve and only the exponential model of the three gives a satisfactory fit there. Also there are good physical reasons to expect an exponential rise (for instance the fact that the airborne fraction is constant is what you would expect for a dynamical system with exponentially increasing emissions). Lastly, the IPCC projections of the rise in CO2 are based on physical models, not statistical models, so it is arguably the mainstream that is concentrating on the basics there. It is always rather easier to see the flaws in the "opposing side" of the argument, and very few of us are not susceptible to that. So I would suggest that your impression of the posters here is not necessarily a very clear one. I wouldn't claim mine is 20-20 either, which is why it is best not to try and second-guess the motivations or backgrounds of others. Much better to stick to the scientific arguments instead.
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  44. johnd @ 91 Much of that 155Gt will have been taken up by the environment, not all of it will stay in the atmosphere (only about 45%). Land use changes *were* the dominant form of until about 1960, when cumulative fossil fuel emissions overtook cumulative land use emissions. To put the land use emissions into context, so far fossil fuel emissions amount to some 320 GtC, judging from the plot on my desk, about 220 GtC of which was emitted since 1960. None of that is controversial, and the IPCC are perfectly aware of it, so I am not sure where your evidence is that it has not been getting the appropriate attention. If you look at a plot of cumulative fossil fuel emissions and cumulative land use emissions, fossil fuel emissions are increasing exponentially, while by comparison land use change emissions are rising almost linearly by comparison. That is more than enough reason to focus on fossil fuel emissions, as it means that in the future fossil fuel emissions will outstrip land use related emissions at an ever increasing rate (unless we do something about it) The data you need to investigate this for yourself (you only need a basic plotting tool, such as excel) are freely available from the carbon dioxide information analysis center As I said, some of us "mere statisticians" do have our uses ;o)
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  45. # RSVP - "Anthropogenic means "caused" by humans. Technically, this is a misnomer, in that it implies that if you are a human, you are causing this problem. In reality, it is use of machinery that is supposedly causing global warming. Machines and fuels that are the result of applied science." So humans are not the cause but the machines they created are. I wonder if I could use that line of reasoning elsewhere? "But officer, you can't arrest me. Yes I was holding the gun that killed him. The gun though is the result of applied science so that is the cause of his death not me."
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  46. "It also may be a folly to assume the Dunning-Kruger effect only exists at one end of the spectrum, (or on one side of the debate) and not throughout, even at times amongst those who consider themselves the elite of their profession." From my own perspective as a layman I would make the assertion that it's not a case of "may be folly" but a case of "is folly". As far as the integrity of scientists is concerned, well there are scientists and then there are scientists. I mean James Hansen is a reputable scientist in his own right. So is Dick Lindzen. Both are quite accomplished but I view the integrity of both in a different light. I have no quarrels over the peer reviewed literature of either, but I question the ulterior motives of Mr. Lindzen based upon his professional associations. I apply the same scrutiny to all professionals. For me it's a "blind faith" issue. The persecution of Michael Mann and others is both absurd and dangerous. It simply reminds me of McCarthy style witch hunts or even the persecution of Leonardo. Dangerous because if allowed to continue it opens the door for the extreme right to openly attack any piece of science that is not conducive with their philosophy. I've heard the hockey stick thing bashed many times in the past, but I must come to it's defence. I'm sure many have made this observation in the past, but I'll make it again. It seems rather odd that the temperature record from 1880 till present matches fairly well the population growth pattern since 1800 (which to me is a reasonable time frame for discussing climate trends, the past decade or two is insufficient for drawing conclusions due to the inherent variability of the various Earth systems). I'm not trained in the sciences, but logic on it's own dictates that there is a strong correlation between rising temperatures and the growth of population since the Agriculural and Industrial Revolutions. Before this time frame it is unlikely that world population levels had that much of an effect on the environment.
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  47. johnd @82, Let me quote the great British statistician D.R.Cox, who is still writing and teaching in his 90s: The first question a statistician asks is "How was these data gathered?". Indeed, the Royal Statistical Society made a submission to the House of Commons enquiry on "Climategate" with some criticisms of the CRU methodology. It was all very fine, but did not make much difference - the correct methodologies gave the same results. Of course, the Daily Mail, a notorious denialist publication, trumpeted "Report criticises faulty methods of climate scientists!", leaving the key facts to the lower paragraphs. That is a good example of what the letter is warning about. From my own observation (as another statistician), the physicists have been teh key players in working out the physical models of how CO2 affects climate. The statisticians are useful adjuncts in getting the data analyses correct.
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  48. #55 Stephen Sullivan Please google "Reg Sprigg" and "Martin Glaessner" to understand how did the scientific community (and Nature magazine) finally came out of the consensus that animals had appeared before the Cambrian. It was because of "extensive peer review", rather because of Glaessner's fame and reputation and his chance interest in some fossils in the Charnwood Forest. The work of Elkanah Billings and Georg Gürich was evidently not enough, however self-evident it appears to us: the whole story of the Ediacaran fossils remind us that scientific consensus is at times overturned not by evidence, but by authority.
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  49. oops...please read "It was NOT because of 'extensive peer review'"
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  50. Dikran Marsupial at 04:52 AM, there are several aspects to land use change. Plants and soil account for about 100Gt of carbon in and out each year, the oceans about the same, therefore given there is about twice as much area covered by oceans than land, one acre of land is worth twice as much as one acre of ocean in terms of it's ability to sequester carbon. When land use changes are made, there may be a one off release of carbon, but over and above that a certain percentage of land will be permanently withdrawn from the carbon exchange cycle, so the one off loss continues to multiply forever. At least fossil fuels can only be burnt once and will eventually be exhausted. With regards to the amounts of carbon released, 155Gt through land use, 320Gt through burning fossil fuels, 220Gt since 1960, even though some has been sequestered, it can be said that there is either 155Gt or 320Gt or even 475Gt more carbon in the atmosphere today than if either or both practices had not occurred. Obviously if all burning of fossil fuels completely ceased today, 6.5Gt of carbon will stop being put into the atmosphere annually, but that won't count for anything if the 100Gt exchange in and out between the plants, soil and atmosphere continues to decline, especially if more land is permanently removed as a carbon sink.
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