The Scientific Debate On Global Warming In One Chart

The next time someone tries to tell you that there's a legitimate scientific debate about man-made global warming, point them to this chart.

It was created by James Powell, an MIT-trained geochemist, longtime Oberlin professor, and former member of the National Science Board (under Presidents Reagan and George H.W. Bush). He searched for all studies published in 2013 that mentioned "global warming," "global climate change," or "climate change," and found 10,885.

Powell combed through the papers and found only two that rejected the idea that humans are responsible for climate change.

"On the one side, we have a mountain of scientific evidence, on the other, ideology and arm-waving," Powell writes.

His analyses of the research in earlier years found similar results. (He describes his methodology here and even invites skeptics to download the data for themselves.)

Some climate change deniers refuse to be moved by the ever-growing "mountain of scientific evidence." But before having a knee-jerk reaction to Powell's findings, consider what they mean, suggests Ashutosh Jogalekar at Scientific American:

I understand as well as anyone else that consensus does not imply truth but I find it odd how there aren't even a handful of scientists who deny global warming presumably because the global warming mafia threatens to throttle them if they do. It's not like we are seeing a 70-30% split, or even a 90-10% split. No, the split is more like 99.99-0.01%.

Isn't it remarkable that among the legions of scientists working around the world, many with tenured positions, secure reputations and largely nothing to lose, not even a hundred out of ten thousand come forward to deny the phenomenon in the scientific literature? Should it be that hard for them to publish papers if the evidence is really good enough? Even detractors of the peer review system would disagree that the system is that broken; after all, studies challenging consensus are quite common in other disciplines. So are contrarian climate scientists around the world so utterly terrified of their colleagues and world opinion that they would not dare to hazard a contrarian explanation at all, especially if it were based on sound science? The belief stretches your imagination to new lengths.

Anyone who points to this cold, long winter as evidence that global warming is a myth may be confusing unpredictable short-term weather patterns with the long-term behavior of the atmosphere. Where you live may have seen a lot of snow this year, but when scientists look at the whole planet, this past decade is still the hottest on record.

And that's exactly why Powell is sounding the alarm, urging people to stop pretending that there's confusion on this issue among serious climate scientists. As the chart above so clearly shows: There's not.

"Very few of the most vocal global warming deniers, those who write op-eds and blogs and testify to congressional committees, have ever written a peer-reviewed article in which they say explicitly that anthropogenic [man-made] global warming is false," Powell writes. "Why? Because then they would have to provide the evidence and, evidently, they don't have it."