That 97.1 Percent

In March, I wrote about Alabama’s Pulitzer Prize-winning columnist John Archibald’s criticism of Dr. John Christy on his appointment to the Environmental Protection Agency’s Science Advisory Board.

Mr. Archibald among other things wrote Dr. Christy’s appointment was “… a smashing success for those who believe our best hope comes with our heads in the sands, listening to the 3 percent of climate scientists who say man is not to blame, instead of the 97 percent, as NASA points out, that agree that climate-warming trends of the past century are extremely likely due to human activities.”

Pulitzer Prize winners are assumed to do thorough research, but how much research is behind NASA’s conclusion? The NASA website states, “Multiple studies published in peer-reviewed scientific journals show that 97 percent or more of actively publishing climate scientists agree: Climate-warming trends over the past century are extremely likely due to human activities.” However, that statement is not based on a NASA study. According to footnote #1 in the NASA statement, the conclusion is based upon a 2013 study by John Cook and three other studies performed between 2004 and 2010.

Mr. Cook’s study, published in Environmental Research Letters, is most often cited to support the 97 percent climate scientist consensus claim and the need for immediate action to mitigate climate change. Mr. Cook, unlike Dr. Christy, is not a climate scientist. He is a Research Assistant Professor at the Center for Climate Change at George Mason University, researching cognitive science. He holds a Ph.D in Cognitive Psychology from the University of Western Australia. However, his primary job is a website blogger on his site, Skeptical Science, that actively promotes action to mitigate climate change.

In 2013, Mr. Cook and eleven Skeptical Science volunteers performed an analysis of 11,944 peer-reviewed papers on climate change and found that 97.1 percent of those papers state a position that explicitly or implicitly suggested that human activity is responsible for some warming.

What NASA doesn’t tell you is that of the 11,844 papers reviewed, only 4,014 took any position on human contribution to climate change. It also doesn’t tell you that Mr. Cook’s team reviewed and coded abstracts five at a time in a video game setting. Volunteers admit to evaluating as many as 50 papers a night.

Many climate scientists, including Craig Idso, Nicola Scafetta, Nir J. Shaviv, Nils-Axel Morner and Richard Tol, complained that Dr. Cook’s study ignored or totally misrepresented their work. That is not the scientific precision expected from NASA.

A team led by David Legates, Professor of Geography at the University of Delaware and former Director of the University of Delaware Center for Climate Research, reviewed Mr. Cook’s findings and the 11,944 underlying papers. That review, published in Science and Education in August 2013 found only 41 papers Mr. Cook’s team reviewed actually endorsed the claim that human activity is causing at least half of the current warming. That is 0.3 percent of the total 11,944 papers and 1.0 percent of the 4,014 papers, not the 97.1 percent consensus claimed by Mr. Cook.

Another study performed in 2009 and published in Eos, Transactions American Geophysical Union by Maggie Kendall Zimmerman, a student at the University of Illinois, as her master’s thesis with her thesis adviser, Peter Doran, is also cited as an authority on NASA’s website. The study asked two questions of 10,257 earth scientists: (1) Do you think mean global temperatures have generally risen, fallen or remained the same since the pre-1800s? (2) Do you think human activity is a significant contributing factor in changing global temperatures?

Only about one-third of the scientists responded and of those responses, the authors only used 79, 75 of which thought humans contributed to global warming. Thus the 97 percent consensus, although it only represents the views of 75 of 10,000 earth scientists surveyed.

Two other studies cited on the NASA website targeted a much more narrow and targeted range of scientific papers. Studies by Naomi Oreskes, a Harvard science historian, and William Anderegg, then a Stanford student, found support for the view that human activities are responsible for most of the observed warming. However, the studies are limited to evaluation of 928 and 200 papers, respectively, and both specifically omit papers by prominent climate scientists that question the scientific consensus.

Of course, Mr. Archibald is not the only one who quotes the 97 percent consensus with certainty. President Obama tweeted, “97 percent of climate scientists agree: #climate change is real, man-made and dangerous.” Then-Secretary of State, John Kerry, said, “Ninety-seven percent of the world’s scientists tell us climate change is urgent.” Others, like Thomas Friedman, routinely use the 97 percent of climate scientists’ argument to intimidate any resistance to climate change arguments.

These studies hardly provide robust evidence and logic to terminate the debate on any issue. You would think a true investigative reporter would be interested in what is behind the movement and urgency to shut down the climate change debate. Otherwise, it is just an opinion column.

I hope you have a good month.