1) A general process and chronology covers a number of cases (not all), so I'll do that first, and then answer the specific question about consensus in global warming.
- a) First, nobody really knows.
- b) People start doing serious studies, and they don't all agree, but evidence starts to pile up around some hypothesis on its way to being a theory.
- c) As elements of a hypothesis get established, people stop arguing about them, but argue about other elements.
- d) At some point, some things are so well-accepted that almost no one doing serious research and doing peer-reviewed publication argues with it. I say almost no one, because there are always a few dissenters, sometimes even quite distinguished ones.
Well, that applies to most scientific arguments ... EXCEPT:
2) Sometimes people find the resulting consensus undesirable for extra-science reasons:
- a) religious
- b) economic
- c) ideological/political
- or combinations.
- - Evolution vs creationism/intelligent design, going on for a long time. (a)
- - Medical science versus smoking and then second round, secondhand smoke. (b) If you can find Allan M. Brandt's "The Cigarette Century" you can learn all about the tactics used to obfuscate the science, and it's the best case, because unlike almost any other case, there is this huge database of public records of internal documents.
(As an example of a dissenter, the great statistician Sir Ronald Fisher disbelieved the smoking-disease linkage right up to his death in 1962, long after there was very powerful evidence.)
A bunch of thinktanks came into existence, learned the skills with tobacco, and then applied them later to:
- - ozone depletion vs CFCs (b,(c))
- - other environmental regulations vs business interests (b, (c))
- - global warming vs fossil fuel (b, (c)
Some of this dates to Frank Luntz, an influential pollster: see Wikipedia entry and the parts of LuntzSpeak, especially:
Hence there is: George C. Marshall Institute, SEPP, CEI, AEI, Heartland, Frontiers of Freedom, SPPI, Fraser Institute (Canada), (and more) mostly in USA, and concentrated around Washington, DC, and with a lot of overlapping participants, often with funding from tobacco companies, very-conservative foundations, ExxonMobil, and coal companies.
3) In any of these, we get into a state where the scientists think there is a strong consensus about something, and will say so if asked, but are working on areas that are in doubt. Papers do not waste words reaffirming the consensus, i.e., very few biologists waste words confirming evolution.
However, the other side constantly attacks the consensus, trying to sow doubt among the public, "teach the controversy" etc. Fighting with this is generally a thankless task for most scientists, as Michael says.
Note that this very different from a real scientific argument, like the multiple-decades-long fight over continental drift, or the shorter fight over the causes of ulcers.
When somebody says there is a consensus, it's not usually that they're trying to close off scientific debate or win an argument, it's just an observation of fact, as seen in the rear-view mirror! Scientists I've talked with (a lot, over 40 years, on many different topics) usually calibrate what they say with uncertainty levels.
Sometimes, the obfuscation strategy backfires into a court case like "Kitzmiller v Dover Area School District", which is one the Discovery Institute did not want to fight, and in which the dissenter witnesses, under oath, got slaughtered in court in front of a conservative, but honest judge John Jones III.
4) AGW consensus.
Assuming this means: "The recent (say since 1975) rise in temperatures is mostly caused by humans, especially by adding GHGs to the atmosphere." I think that has actually been mostly in place (scientifically) before 1990, although as always, people argue about the details.
REPUBLICAN President George H. W. Bush said, in:
"President Bush announced today that the United States has agreed with other industrialized nations that stabilization of carbon dioxide (CO2) emissions should be achieved as soon as possible." that was 1989.
The more it looked like people might actually do something to conserve fossil-fuels, and the stronger the statements got by the IPCC, the louder the anti-AGW PR got, and for whatever reason, some parts of the Republican party took a distinct anti-science turn (see Chris Mooney's book "The Republican War on Science."
5) At the February 2004 AAAS meeting, the (prestigious) George Sarton Award lecture was "The Scientific Consensus on Climate Change: How Do We Know We're Not Wrong?" of which you can find a slightly-updated version at:
This was given by UCSD Professor Naomi Oreskes, who is a well-published, award-winning geoscientist and science historian, and it is well worth reading.
Naomi's original talk mentioned a quick experiment she had done, which was searching the ISI Web of Science for "global climate change" in papers published 1993-2003 and looking at abstracts and assessing them, expecting to see when and how the consensus got established, and was surprised to find that the consensus was already there.
However, this got a strong audience response, and she ended up doing a 1-page essay for Dec 2004 Science (which does not give out pages casually):
Bennie Peiser (a UK Social anthropologist!) wrote a letter to Science (not accepted) attacking these results, in 2005. It turned out that he simply lacked the expertise, and this was refuted, rather thoroughly.
The other side constantly raises doubts about the consensus, and often attacks Oreskes, sometimes quite personally via threatening letters.
The latest one is a bizarre combination of a Britsh Lord Christopher Monckton, 3rd Viscount of Brenchley, a London endocrinologist, Klaus-Martin Schulte, who wrote an article (not yet published) that tried to refute Oreskes and teh consensus again. Even without being published, it managed to generate:
Google: less than half published scientists endorse global warming
--> 700,000 hits
I.e., regardless of the truth, the desired publicity was accomplished, using a well-tuned PR machine centered in Washington, DC.
There also turned out to be plagiarism, threats of lawsuits, letters sent to Oreskes' Chancellor and then publicized via Business Wire, etc, etc.
So: there is a large machine crying "no consensus, there is doubt" which is perfectly happy to publicize
- an indirect reference to a paper by an endocrinologist
- who turns out to be fairly clueless about climate science,
- and whose paper couldn't even get published in the poorly-regarded journal to which it had been submitted.
This story is spread across various blogs, but some key ones are:
Note that the above, except for the italicized intro, was entirely written by John Mashey and not myself.
Update: It looks like it's time for John Mashey to get his own blog, since he has a lot of interesting things to say but says them on other people's blogs.