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From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.
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And I'm Melissa Block. Yesterday, President Obama sent out a tweet drawing attention to a study about climate change. The study found that scientists who say climate change is largely caused by human activities vastly outnumber the skeptics. NPR's Richard Harris has more on the study that caught the White House's attention.
RICHARD HARRIS, BYLINE: Academies of science around the world agree that climate change is real and caused largely by burning fossil fuels. So do many professional scientific organizations. Polls of scientists point to the same conclusion and so, now, does a review of the scientific literature. It shows that 97 percent of the time, scientists who express a view say that human activity is warming the planet.
ED MAIBACH: It's not a surprise at all. But it is the best, the most ambitious and biggest study done on this point, to date.
HARRIS: Ed Maibach heads the Center for Climate Change Communication at George Mason University. He wasn't involved in the study, but one of his students was. Volunteers combed through 12,000 studies from around the world. In about a third of the cases, the authors took a position about climate change. In that group, only 2 percent of those papers rejected the idea that human activities cause climate change. This is published in the journal Environmental Research Letters. And although this consensus isn't news to anybody who studies the climate, Maibach's opinion surveys show the public isn't aware of it.
MAIBACH: Less than half of the public understands that there's widespread scientific agreement about climate change. About 40 percent believe that there's a lot of disagreement among the scientists.
HARRIS: And it's easy to see why that might be the case if you looked at the blogosphere, where skeptics abound. But it's not true in scientific publications, which are vetted by peer view. Maibach says part of this is human nature. People naturally tend to give undue weight to minority opinions.
MAIBACH: This is a particular foible of the human mind that makes us so susceptible to outlier opinions and as a counterweight to what otherwise would be overwhelming proof from - you know, based on the scientific consensus.
HARRIS: But even with this degree of doubt, most Americans Maibach surveys agree that climate change is happening. That's a pretty volatile number, though.
MAIBACH: People's assessments of climate change are very susceptible to what they've recently experienced in the weather.
HARRIS: And after this past cold winter, American opinion about the existence of climate change dropped seven percentage points, to 63 percent. Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.