As if the backing of NASA, 18 independent American scientific societies, and an intergovernmental panel established under the United Nations weren't enough to quell the protests popping up in comment sections across the Internet, a new study published in the journal Environmental Research Letters confirms — once again — that climatologists almost unanimously believe that climate change is directly related to human-made carbon emissions.

Researchers pored over nearly 12,000 peer-reviewed scientific papers from 1991 to 2011. These papers, according to Michael Todd at Pacific Standard, represented the work of 29,083 authors and 1,980 journals. The conclusion could hardly be stronger: 97 percent of scientists agree that anthropogenic, or human-caused, global warming exists.

"That suggests both a consensus, and an overwhelming one," adds Todd.

"The public perception of a scientific consensus on [anthropogenic global warming] is a necessary element in public support for climate policy," conclude the study's authors. And yet, according to Pew Internet Research (PDF), 57 percent of Americans are unaware that there is an overwhelming scientific consensus.

Why the discrepancy? Big Oil is at least partly to blame. Following the negotiation of the Kyoto Protocol in 1998, Popular Science reports that the American Petroleum Institute organized a task force to spend $5.9 million to "discredit climate scientists and quash growing public support of curbing emissions." The strategy, according to a leaked memo titled the "Global Climate Science Communications Plan," included efforts to "recruit, train, and pay willing scientists to sow doubt about climate science among the media and the public."

Blame politicians, too. When the president of the United States casts doubt on the link between human-made emissions and climate change, people are sure to follow.

Times may be changing, though. Although "conservative white males" are more likely to be skeptics, as Scientific American noted in a controversial study published in 2011, the issue is beginning to divide conservatives, with more Republicans coming out in support of climate science. (When asked if he believed in man-made global warming in April, Mayor Rex Parris of Lancaster, California, responded: "I may be a Republican. I'm not an idiot.")

"There is a divide within the party," Samuel Thernstrom, an environmental policy scholar who served on President George W. Bush's Council on Environmental Quality, told National Journal earlier this month. "The position that climate change is a hoax is untenable."

(Via Pacific Standard)