There is probably no better explanation of why this stat was cooked up than the op-ed by Lawrence Solomon in the Financial Post of Jan 3, 2011.
To their embarrassment, most of the pundits and press discovered they were mistaken — those 2,500 scientists hadn’t endorsed the IPCC’s conclusions, they had merely reviewed some part or other of the IPCC’s mammoth studies. To add to their embarrassment, many of those reviewers from within the IPCC establishment actually disagreed with the IPCC’s conclusions, sometimes vehemently."
In other words, those in charge of the IPCC who would like to claim the authors of their report ran into a snag - the scientists who contributed data to this thought in some cases the conclusions were nuts. How then to portray confidence in the IPCC results?
Enter Maggie Kendall Zimmerman, writing her masters thesis in 2008 and her advisor, associate professor Peter Doran. Sadly what their report showed that of all the scientists polled, 75 out of 77 people getting climate grants think warming is man made and a problem. You can't even show all people getting climate grants believe the AGW hypothesis. And 99.9% reject it.
Maggie and her thesis advisor decided on online poll of scientists but the they started out ignoring any scientists unlikely to yield the "proper conclusion". Anybody having anything to do with space was ruled out and never mind this means all the climate researchers at NASA and CERN who have hard evidence the sun has more to do with warming than anything else.
Of these remaining scientists only about 30% bothered to answer the throwaway questions posed in a tiny online email survey - many scientists apparently reported it seemed trite and ignored it. These are the questions:
1 When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant? 2 Do you think human activity is a significant contributing factor in changing mean global temperatures?
Only 90% answered the first question in the affirmative.
Only 82% answered the second question in the affirmative and that's with only 90% of the respondents (recall the other 10% presumably know it was warmer than now in: 1936, 1300 and 0AD) So roughly one in five people did not support the idea warming actually existed at all. Not entirely unreasonable when you realize the summer of 1936 was hotter then any summer since and it was evern more hotter in 1300 and even hotter yet in 0BCE.
82% doesn't sound that airtight so they excluded people that hadn't published a climate paper in a year. This took the number of respondents down from 3000 to 300 but the confidence percentage was still not newsworthy.
So, next round of cuts: limit responses to those who self identify as "climate scientists". Quoting the thesis itself:
The thesis is availeble here: http://probeinternational.org/library/wp-content/uploads/2010/12/012009_Doran_final1.pdf
It's a two page quickie, the first page has the 97% explanation.
Statistics can be useful when the questions asked are intelligent, the sample size large and random. This is a clear case of cherry picking to zero on on the desired answer. So, 97% (of 77 people on climate grants) think AGW is real and harmful.
99.97% of the rest of scientists (~10K) don't agree.
The latter is actually more meaningful than the former.
Cook et. al. (2013) have a more accurate breakdown of her "work":
...and trash it more formal sense and in greater depth; the statistical methods in Doran are now taught in university statistics classes at, at least my Alma Mater as how not to use statistics.
So in conclusion when you assert "97% of the worlds scientists support the AGW hpothesis" you're really saying "75 people out of over 10,000 agree" and you might as well say "99% of all scientists think AGW is batshit insane".
But what you're really saying is:
1) That is, the logical fallacy of the argument from ignorance.
2) That is, the logical fallacy of proof by authority.
In essense when somebody says "97%" they're admitting they know noting of climate and nothing of the mathematics the field of climate science is based on. Recall the warming hypotheis was from a model and the measure of a good model is how well it tracks reality. It neevr has of ocurse, the models blew up years ago and it's not warmer each year than the previous year like the models predicted, not have the ice caps or snow packs on mountains metled. In fact you will not be able to find a single prediction made by climate alarmists that ever came true.
Not a single one, ever.
Even if the statistic were true, so what? It's still the fallacy of the argument from ignorance and argument from authority. This is not a replacement for truth, it's an opinion. To restate in more compare terms: never confuse consensus for truth
Not much it turns out. Note also this quote from Legates Et Al (2013)
Learning and Teaching Climate Science: The Perils of Consensus Knowledge Using Agnotology
We hear about "climate denier" a lot.
1) Science advanced from skepticism. Either a flaw is found or the hypothesis is made stronger.
2) To use rhetoric instead of truth in an argument it means there wa no truth. It's always easier to explain why rather to to point out why you think the other guy is wrong.
I Don't need to say "he's a liar who can't add" if somebody asserts 2+2=7. I'd just say 2+4=4. Mmmkay?
3) Now, where is this proof carbon dioxide causes an increased yearly average temperature? Is "yearly average temperature" a meaningful idea and number?
Do you now the answers to these questions?
Why do we see more articles on climate than pollution when pollution kills millions a year while climate change - which was all based on some models that y 2012 had failed - has never killed anyone? Plus, also falsified by the end result of the ozone hole thing. Seen that?
Are yu aware this is a partisan political issue and not a scientific one? This all comes from the Clinton Foundation which recycles pollut dollars into fake climate news and memes.