President Obama recently tweeted, “@BarackObama: Ninety-seven percent of scientists agree: #climatechange is real, man-made and dangerous.” Environmental groups and their hallelujah choir in the mainstream media repeat the claim endlessly. Even NASA says on its Web site, somewhat more cautiously, “Ninety-seven percent of climate scientists agree that climate-warming trends over the past century are very likely due to human activities.”
So the debate is over, right? No, not hardly.
The fiction that most scientists believe climate change is “man-made and dangerous” can be traced to a handful of surveys and abstract-counting exercises that have been repeatedly debunked and contradicted by more reliable research. Yet the myth lives on in the minds of liberal activists. So let’s settle this once and for all.
The United Nations Says So
The United Nations’ Intergovernmental Panel on Climate Change (IPCC) claims to speak on behalf of more than 2,500 scientists when it says man-made global warming is a serious problem. But few of those scientists wrote about or reviewed research having to do with the key question of attribution: How much of the temperature increase and other climate changes observed in the twentieth century was caused by man-made greenhouse gas emissions?
For the Fourth Assessment Report, only 62 researchers were responsible for reviewing the chapter that attributed climate change to man-made greenhouse emissions. Fifty-five of those had associations with environmental advocacy groups. Of the seven impartial reviewers, two disagreed with IPCC’s conclusion. That leaves only five credible scientific reviewers who unequivocally endorsed IPCC’s conclusion.
Five is a far cry from 2,500 and is not evidence of consensus.
Naomi Oreskes Says So
In 2004, Science magazine published an opinion essay by a little-known science historian named Naomi Oreskes. Oreskes claimed to have examined abstracts from 928 articles published in scientific journals from 1993 and 2003, abstracts she found by searching an online database. She concluded 75 percent of the abstracts either implicitly or explicitly supported the alarmist view while none directly dissented.
Problem number one: Oreskes lacked the scientific training to accurately categorize the abstracts she read, so scores of scientists quickly reported their own papers opposing the “consensus” were left out or misinterpreted. More than 1,300 such articles now appear in an online bibliography at populartechnology.net.
Problem number two: The abstracts of academic papers often contain claims that aren’t substantiated in the papers. (This is according to research by Park et al. reported in the February 6, 2014 issue of Nature, the world’s most prestigious science journal.) So Oreskes’ methodology is flawed.
Problem number three: In 2008, medical researcher Klaus-Martin Schulte used the same database and search terms as Oreskes to examine papers published from 2004 to February 2007 and found fewer than half endorsed the “consensus” and only 7 percent did so explicitly. Schulte found 31 papers (6 percent of the sample) that explicitly or implicitly rejected the “consensus.” Schulte’s findings were published in a peer-reviewed journal.
So no, Oreskes didn’t find a “scientific consensus.” Not even close.
Doran and Zimmerman Say It’s So
In 2008, a University of Illinois college student, Maggie Kendall Zimmerman, conducted a two-question online survey for her master’s degree thesis. A year later, in an article in EOS coauthored with her thesis advisor, Peter Doran, she claimed “97 percent of climate scientists agree” that global temperatures have risen since before the 1800s and that humans are a significant contributing factor.
This study, too, has been debunked. First, the survey asked the wrong questions. Most scientists who are skeptical of catastrophic global warming would answer “yes” to both questions. The survey was silent on whether the human impact is large enough to constitute a problem.
Second, the college student did not survey solar scientists, space scientists, cosmologists, physicists, meteorologists, and astronomers, all scientists most likely to be aware of natural causes of climate change.
Third, the “97 percent” figure represents the views of only 79 of the 3,146 respondents who listed climate science as an area of expertise and said they published more than 50 percent of their recent peer-reviewed papers on climate change. Seventy-nine scientists do not constitute a consensus.
William Love Anderegg Says It’s So
In 2010, another college student, William R. Love Anderegg, claimed to find “97–98 percent of climate researchers most actively publishing in the field support the tenets of ACC [anthropogenic climate change] outlined by the Intergovernmental Panel on Climate Change.” His findings were published in Proceedings of the National Academies of Sciences.
What Love Anderegg actually found was 97 to 98 percent of the 200 most prolific writers on climate change believe “anthropogenic greenhouse gases have been responsible for ‘most’ of the ‘unequivocal’ warming of the Earth’s average global temperature over the second half of the 20th century.” The views of 200 researchers out of the hundreds of thousands of earth scientists who have contributed to the climate science debate is not evidence of consensus. More likely, it is evidence of editorial bias, documented by Park et al. in the Nature article cited earlier.
Once again, the author did not ask if the writers believe global warming is a serious problem or if science is sufficiently established to be the basis for public policy.
John Cook Says It’s So
In 2013, a strident global warming alarmist and blogger named John Cook claimed a review he performed, with help from some of his friends, of the abstracts of peer-reviewed papers published from 1991 to 2011 revealed 97 percent of those that stated a position on man-made global warming supported his own alarmist view. His findings were published in Environmental Research Letters.
Do I need to point out again that counting abstracts is not a valid methodology? Or report again that many of the scientists whose work questions the consensus have protested that Cook et al. ignored or misrepresented their work?
No surprise, this study was quickly debunked by a paper by Legates et al. published in Science & Education. Legates et al. reviewed the same papers and found “only 41 papers – 0.3 percent of all 11,944 abstracts or 1.0 percent of the 4,014 expressing an opinion, and not 97.1 percent – had been found to endorse the standard or quantitative hypothesis.”
Rigorous international surveys of climate scientists conducted by German scientists Dennis Bray and Hans von Storch have found most scientists disagree with the consensus on key issues such as the reliability of climate data and computer models. Most say they do not believe key climate processes such as cloud formation and precipitation are sufficiently understood to predict future climate changes.
Surveys of meteorologists repeatedly find a majority oppose the alleged consensus. A survey conducted by the American Meteorological Society of its members in 2012, for example, found only 39.5 percent of those responding said they believe man-made global warming is dangerous.
Of the various petitions circulated for signatures by scientists on the global warming issue, the one that has garnered by far the most signatures – more than 31,000 names – says “there is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate.”
Who Do You Believe?
So who should you believe? President Obama and NASA apparently believe a couple of college students and an alarmist blogger. If you’ve made it this far into this essay, I hope you have some doubts about their “research.”
The real moral of the story is this: Don’t trust anyone who says there’s a scientific consensus on global warming. Don’t “believe” in global warming because that’s what you think others believe. Look under the hood and figure it out yourself.
That’s what 97 percent of climate scientists do.