Larry Bell writes in his weekly Forbes column about that oft repeated but less than truthy “98% of all scientists” statistic. Supposedly, this was such an easy and quick to do survey, it was a no-brainer according to the two University of Illinois researchers who conducted it:
To maximize the response rate, the survey was designed to take less than 2 minutes to complete, and it was administered by a professional online survey site ( www.questionpro.com ) that allowed one-time participation by those who received the invitation.
I think it is hilarious that so few people who cite this survey as “proof” of consensus actually look into the survey and the puny response numbers involved. So, I decided to graph the data to give some much needed perspective. Apparently, the majority of AGU members polled didn’t think this poll on climate change consensus was worth returning. – Anthony
That Scientific Global Warming Consensus…Not! – Forbes
By Larry Bell
So where did that famous “consensus” claim that “98% of all scientists believe in global warming” come from? It originated from an endlessly reported 2009 American Geophysical Union (AGU) survey consisting of an intentionally brief two-minute, two question online survey sent to 10,257 earth scientists by two researchers at the University of Illinois. Of the about 3.000 who responded, 82% answered “yes” to the second question, which like the first, most people I know would also have agreed with.
Then of those, only a small subset, just 77 who had been successful in getting more than half of their papers recently accepted by peer-reviewed climate science journals, were considered in their survey statistic. That “98% all scientists” referred to a laughably puny number of 75 of those 77 who answered “yes”.
That anything-but-scientific survey asked two questions. The first: “When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?” Few would be expected to dispute this…the planet began thawing out of the “Little Ice Age” in the middle 19th century, predating the Industrial Revolution. (That was the coldest period since the last real Ice Age ended roughly 10,000 years ago.)
The second question asked: “Do you think human activity is a significant contributing factor in changing mean global temperatures?” So what constitutes “significant”? Does “changing” include both cooling and warming… and for both “better” and “worse”? And which contributions…does this include land use changes, such as agriculture and deforestation?
Read the whole article: That Scientific Global Warming Consensus…Not! – Forbes
Here’s the survey as it appeared in EOS:
EOS, TRANSACTIONS AMERICAN GEOPHYSICAL UNION, VOL. 90, NO. 3, PAGE 22, 2009 doi:10.1029/2009EO030002
Examining the Scientific Consensus on Climate Change
Peter T. Doran, Earth and Environmental Sciences, University of Illinois, Chicago
Maggie Kendall Zimmerman, Earth and Environmental Sciences, University of Illinois, Chicago
Fifty-two percent of Americans think most climate scientists agree that the Earth has been warming in recent years, and 47% think climate scientists agree (i.e., that there is a scientific consensus) that human activities are a major cause of that warming, according to recent polling (see http://www.pollingreport.com/enviro.htm). However, attempts to quantify the scientific consensus on anthropogenic warming have met with criticism. For instance, Oreskes  reviewed 928 abstracts from peer-reviewed research papers and found that more than 75% either explicitly or implicitly accepted the consensus view that Earth’s climate is being affected by human activities. Yet Oreskes’s approach has been criticized for overstating the level of consensus acceptance within the examined abstracts [Peiser, 2005] and for not capturing the full diversity of scientific opinion [Pielke, 2005]. A review of previous attempts at quantifying the consensus and criticisms is provided by Kendall Zimmerman . The objective of our study presented here is to assess the scientific consensus on climate change through an unbiased survey of a large and broad group of Earth scientists.
…and the paper with the data: http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf
UPDATE: The original Larry Bell article referenced 98%, but the actual calculated number is 97.4%. On the web, 97 and 98% values are both referred to individually in articles, as well as a range of 97-98% I’ve amended the title to use the range – Anthony