It turns out the climate change deniers were right: There isn’t 97% agreement among climate scientists. The real figure? It's not lower, but actually higher.
The scientific “consensus” on climate change has gotten stronger, surging past the famous — and controversial — figure of 97% to more than 99.9%, according to a new study reviewed by msnbc.
James L. Powell, director of the National Physical Sciences Consortium, reviewed more than 24,000 peer-reviewed papers on global warming published in 2013 and 2014. Only five reject the reality of rising temperatures or the fact that human emissions are the cause, he found.
“It’s now a ruling paradigm, as much an accepted fact in climate science as plate tectonics is in geology and evolution is in biology,” he told msnbc. “It’s 99.9% plus.”
Powell, a member of the National Science Board under Presidents Ronald Reagan and George H.W. Bush, decided to share an exclusive draft of his research on Tuesday — just days before Pope Francis is set to deliver a major address on climate change — because he doesn’t want his holiness to reference outdated numbers.
“I don’t want the Pope to say 97%,” Powell said by phone, arguing that accuracy now is more important than ever. “It’s wrong, and it’s not trivial.”
Pope Francis is preparing to charge into the political debate over climate change, citing “a very consistent scientific consensus” and the risk of “unprecedented destruction,” according to a leaked draft of Thursday’s papal encyclical.
The notion of 97% agreement among climate scientists started with studies in 2009 and 2010. It wasn’t until a 2013 study, however, that the figure went viral. President Barack Obama tweeted it. The comedian John Oliver set up a slapstick debate between a climate change denier and 97 of his peers.
But Powell argues that acceptance of man-made global warming has grown. The author of a new Columbia University Press book on scientific revolutions used an online database to compile a mountain of global warming papers published in the last two years.
He also tried a different approach than the earlier studies. Rather than search for explicit acceptance of anthropomorphic global warming, Powell searched for explicit rejection. All the papers in the middle, he figured, weren’t neutral on the subject — they were settled on it.
The results include work from nearly the entire population of working climate scientists — close to 70,000 scientists, often sharing their byline with three or four other authors. They also include a dwindling opposition: Powell could find only four solitary authors who challenged the evidence for human-caused global warming.
That’s a rate of one dissenting voice for every 17,000 agreeing scientists, and it’s not a strong voice. Powell called the four dissents “known deniers and crackpots,” and noted that their work had been cited only once by the wider academic community.
Naomi Oreskes, a professor of the history of science at Harvard, hasn’t read the Powell paper but she doesn’t doubt the general direction of the findings.
Back in 2004, she became the first researcher to claim a “consensus” on climate change, finding a roughly 75% agreement within the literature.
“Scientists have done so much more work since then,” she said. For me, as a historian of science, it really feels like overkill. One starts to think, how many more times do we need to say this before we really get it and start to act on it?”
One reason for inaction of course is politics. Many of the world’s leaders still doubt the science of climate change, assuming incorrectly that it’s unsettled or exploratory. The view is especially prevalent among the current crop of Republican presidential candidates.
Earlier this month, for example, former Pennsylvania Sen. Rick Santorum told Fox News that the pope would be “better off leaving science to the scientists.” Jeb Bush, Marco Rubio and Ted Cruz, meanwhile, claim that the science remains vague or is made up entirely.
That raises a second reason for inaction, according to Oreskes: intentional deception. Oreskes is the co-author of the “Merchants of Doubt,” a book that demonstrated how interest groups had undermined the science on tobacco, ozone depletion, acid rain and now climate change.
Many self-proclaimed “climate skeptics” no longer deny that the globe is warming, and some even acknowledge a human role in the new heat wave. Instead, they now say, warming is real — it just isn’t dangerous. They also attack the idea of a consensus, whatever the percentage.
“Nothing has really changed there,” said Oreskes. “The details shift but the overall picture remains the same. It’s a bit like Monet’s water lilies; it can look different at different at different times of day but it’s the same picture.”
Powell, however, hopes his work can finally close the debate, end the notion of doubt, move the frame ahead.
“There isn’t any evidence against global warming and there isn’t any alternative theory,” he said. “We’ve been looking for negative feedbacks and we’ve never found one that amounts to anything. It’s not impossible that we will, but I wouldn’t bet my grandchildren’s future on it.”