97% Climbs to 99.5%: Obama Increases Percentage of Scientists Who Agree on Climate Change

By Barbara Hollingsworth | December 2, 2015 | 2:10 PM EST

President Obama gestures to reporters at a press conference at the Organization for Economic Cooperation and Development in Paris on Dec. 1, 2015. (AP photo)

(CNSNews.com) – President Obama said Tuesday that he's confident his successor will honor any climate change agreement negotiated in Paris becasue "99.5 percent of scientists and 99 percent of world leaders" think that climate change "is really important." 

Obama’s claim that there is a 99.5 percent consensus among scientists on climate change represents a 2.5 percent increase since May 16, 2013, when the president tweeted: “Ninety-seven percent of scientists agree: #climate change is real, man-made and dangerous.”

“Everybody else is taking climate change really seriously. They think it's a really big problem. It spans political parties,” Obama said during his press conference in Paris, where the United Nations’ COP 21 climate change summit is being held.

Responding to a question about whether foreign leaders can believe the U.S. will keep any commitments it makes in Paris if a Republican succeeds him in the White House, Obama said:

“Whoever is the next president of the United States, if they come in and they suggest somehow that that global consensus — not just 99.5% of scientists and experts, but 99% of world leaders — think this is really important, I think the president of the United States is going to need to think this is really important.”

The origin of the “97 percent” statistic has been traced back to a 2009 study by University of Illinois/Chicago graduate student Kendall Zimmerman, who sent a survey to 10,257 earth scientists asking them two questions:

 “When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?” and

 “Do you think human activity is a significant contributing factor in changing mean global temperatures?”

Eighty-two percent of the 3,146 scientists who completed the survey (a 30.7% response rate) answered “yes” to question 2. That figure included 75 of the 79 individuals (97.4%) who self-identified themselves as climate scientists.

In a 2013 paper published by the Institute of Physic’s IOPScience and cited by NASA, University of Queensland climate communication fellow John Cook also stated that 97 percent of scientists who took a position on global warming agreed that humans were the primary cause.

“Among abstracts expressing a position on AGW [anthropogenic global warming], 97.1% endorsed the consensus that humans are causing global warming,” Cook and his co-authors stated.

However, a peer review of Cook’s paper by David Legates, a former state climatologist and professor at the University of Delaware, that was published in the April 2015 issue of Science and Education debunked the 97 percent consensus figure.

Legates pointed out that only 41 of the 11,944 academic papers Cook examined in his meta-analysis (0.3%) explicitly stated that most of the global warming since 1950 was caused by human activity.

 “It is astonishing that any journal could have published a paper claiming a 97% climate consensus when in the authors’ own analysis the true consensus was well below 1%,” Legates wrote.

Cook’s paper was also criticized by other scientists for what they said was a number of methodological errors.

“Probably the most widely repeated claim in the debate over global warming is that ‘97% of scientists agree’ that climate change is man-made and dangerous,” the three authors of Why Scientists Disagree About Global Warming wrote in a just-released book published by the Heartland Institute.

“This claim is not only false, but its presence in the debate is an insult to science.”