If you follow the news on climate change, you hear it over and over again: 97 percent of climate scientists agree that global warming is real and caused by human activity.
On Tuesday, geochemist James Lawrence Powell took that rhetoric even further, releasing a study finding that out of all 10,855 climate studies published in peer-review journals during 2013, only two of them explicitly rejected anthropogenic global warming. Put another way, that’s roughly .02 percent of published research that denies outright the existence of man-made climate change.
If those numbers sound staggering, it’s probably because of how little they affect the intense, non-scientific debate that often surrounds climate change in the political realm. Politicians tasked with making crucial decisions on national energy policy and air pollution have a propensity for ignoring the science. Approximately 56 percent, or at least 130 members, of the current Republican caucus in the House of Representatives deny the basic tenets of climate science. Sixty-six percent, or at least 30 members, of the Senate Republican caucus also deny the reality of climate change.
Compare that with how actual scientists view the subject, and you get this:
Though it may be tempting to look at Powell’s study and conclude that there is a 99.98 percent scientific consensus on the existence of climate change, that is not what the results state. Powell’s methodology looked only for explicit rejection of man-made climate change, and not for endorsement of the idea. Therefore, Powell cannot scientifically conclude that the rest of the papers accepted the idea just because they didn’t reject it.
This differs from the methodology used by Dana Nuccitelli and John Cook, who surveyed more than 12,000 peer-reviewed climate science papers to find a 97 percent consensus in the peer-reviewed literature that humans are causing global warming. The methodology used by Cook and Nuccitelli was more inclusive, looking for both explicit and implicit rejection of the idea, and also looking at whether the other papers implicitly or explicitly endorsed man-made climate change. Because Cook and Nuccitelli’s paper sorted out endorsements, it is scientifically able to cite a 97 percent scientific consensus. More information on the extent of Congressional climate denial — and the money that funds it — can be found here.
Andrew Breiner contributed graphics for this post.