An article of faith in the climate warming community is that a “scientific consensus” exists on humanity’s role in raising the planet’s temperature. An equal and opposite article of faith among global warming skeptics (to check their temperature scroll down the comments section on any mainstream media article about climate change), or at least skeptics of anthropogenic climate change, is that this consensus is at best less than sweeping and at worst illusory.
A new study published online today in the journal Environmental Research Letters puts a figure on how real this (genuine) scientific consensus is. The takeaway figure? Ninety-seven percent of scientific papers that take a position on anthropogenic climate change say it exists, and of authors of those papers, 97 percent endorse the idea of human-caused warming. That suggests both a consensus, and an overwhelming one. (Yes, that's right in line with smaller past surveys, but no, still not universal.)
I see value in continuing to hammer home that the scientific establishment has reached a consensus that people are warming the planet (and perhaps that people can cool it down).
As the paper’s nine authors, headed by University of Queensland physicist John Cook, conclude: “A systematic, comprehensive review of the literature provides quantitative evidence countering this assertion [that a consensus is collapsing]. The number of papers rejecting [anthropogenic global warming] is a miniscule proportion of the published research, with the percentage slightly decreasing over time.”
While the researchers used crowd-sourcing to help analyze the nearly 12,000 papers reviewed, the crowd itself is in no way so unified. As the paper notes, there is a “consensus gap” between science and the man on the street; a Pew poll from March reported that while 69 percent of Americans believe there is “solid evidence” the Earth is warming, only 42 percent accept this is mostly due to human activity. (Those are actually the highest figures in five years; as recently as 2006 the relevant numbers were 77 and 47 percent respectively.)
As Cook was quoted in a press release accompanying the paper: “There is a gaping chasm between the actual scientific consensus and the public perception. Making the results of our paper more widely-known is an important step toward closing the consensus gap and increasing public support for meaningful climate action.” The business world at any rate, from insurers to oil executives, is starting to cotton to the reality.
While the solid numbers observed in the Cook paper should erase any lingering argument that the consensus is either bogus or fragile, there are enough caveats that this is unlikely to be the last word.
The biggest in my mind is that Cook is the founder of SkepticalScience.com (“Getting skeptical about global warming skepticism”), and the 24 volunteers who rated the scientific papers were recruited from that website. I happen to like SkepticalScience, and think it does valuable work in counteracting the charlatans and doubt makers out there. Still, it’s obvious that its advocacy will color perception of the results. There are caveats to my caveats; the Cook paper was peer reviewed and the scientists whose stances were rated were contacted and the responses of those who replied agreed with the evaluators’ assessments.
But not everyone contacted agreed with the researchers’ categories for rating attitudes. Before he shuttered his website on climate science, meteorologist Roger Pielke Sr. wrote about being contacted by the Cook team, and he suggested some refinements that might better catalog his own nuanced views. (I want to be careful in categorizing Pielke père. He’s not a denier but he is skeptical about the consensus view, especially about the role of carbon, even as he acknowledges that human activity does affect the climate.) Finding the survey “much too limited,” he argued, “It appears they are writing their questions to reinforce a preconceived perspective, rather than complete an actual survey of the diversity of viewpoints in climate system science and the role of humans in its alteration.” Since charting diversity wasn’t the authors’ goal, I doubt they lost much sleep over that shortcoming, but it does seem they were focused on a rather narrow outcome—and achieved it.
Nonetheless, I see value in continuing to hammer home that the scientific establishment has reached a consensus that people are warming the planet (and perhaps that people can cool it down).
INTO THE WEEDS ON THE PAPER'S METHODOLOGY
Cook and Co. looked at 11,944 abstracts—the little summaries at the front of scientific papers—from peer-reviewed articles published in the two decades from 1991 to 2011 that included the words “global climate change” or “global warming.” These papers represented the work of 29,083 authors and 1,980 journals, but were still only about a quarter of the papers mentioning “climate change” in the same period that a search on the Web of Science database turned up. Of those almost 12,000 papers examined, a third stated a position on human-caused climate change—and that’s where the 97 percent figure comes from. The study’s authors note that many of the remaining papers, while they didn’t give an opinion on the role of human activity, took anthropogenic climate change as a given (i.e. those that discussed mitigation strategies).
It’s worth noting that 97 percent of scientists contacted did not feel they had taken a position endorsing the primacy of anthropogenic climate change in their respective papers. That figure is drawn from those who stated a position in their journal paper and then responded to the Cook questionnaire. About 63 percent of respondents felt their paper or papers explicitly endorsed anthropogenic climate change, but only two percent felt their work explicitly rejected it. Still smells like consensus to me.