Robson: 97 percent wrong
March 25, 20193:16 AM John Robson5 Comments
If you dare raise questions about climate change, as we’re doing at the Climate Discussion Nexus, somebody will immediately try to clobber you with the claim that 97% of world scientists agree that it’s an urgent manmade crisis, unlike you idiots. But the thing is, they don’t. It’s a made-up number… and if someone is that smugly and aggressively wrong about something that important you wonder what else they don’t know.
Many people assume the 97% figure is solid enough to be used as a club. After all, Barack Obama tweeted it: “Ninety-seven percent of scientists agree: #climate change is real, manmade and dangerous.” And if you can’t trust politicians, who can you trust? Hey, wait a minute.
It’s especially odd that journalists keep repeating it without ever looking at it sideways. When I joined the profession, way back when newspapers made money, there was a newsroom maxim “If your mother says she loves you, check it out.” So before ringing endless changes on “experts agree” you’d think they’d make a few phone calls, or Google, to figure out where it came from.
Especially because this number doesn’t just look funny, it smells funny. There are millions of scientists in the world, most of whom don’t work on climate change. Who supposedly surveyed them? When? How? And what did they say?
Astoundingly, the 97% number comes from a handful of methodologically feeble studies beginning with historian of science Naomi Oreskes in 2004 claiming she’d looked at 928 articles about climate change in scientific journals and 75 percent of them endorsed the “consensus view” that “Earth’s climate is being affected by human activities” while none directly disputed it. Which you’ll notice says nothing about it being dangerous or manmade. Nor did it claim 97% agreement. (And even her 75% didn’t withstand subsequent scrutiny.)
Five years later, two University of Illinois researchers sent an online survey to over 10,000 Earth scientists asking two simple questions: Did they agreed that global temperatures had risen in the last couple of centuries and did they think human activity was a significant contributing factor. They got 3,146 responses, so at best about 30% even of that sample. Of those 90 percent said yes to the first question and 82 percent yes to the second. Again no manmade, no dangerous, and where’s the 97%?
Well, the researchers discarded all but 77 responses from people who self-described as climate experts, of whom 75 said yes to the second question. And 75 out of 77 is 97%. But there’s still no mention of danger and even this very skewed sample only said our influence was significant. Not overwhelming. Not even dominant.
Another survey by Australian researchers in 2013 claimed to have looked at 12,000 scientific papers on climate change and found 97% agreement… that greenhouse gases had some impact on global warming. Again not dangerous and not manmade. Also, it turned out, not true. Nearly two-thirds of the papers said nothing on the consensus. Of the 34% that did, 33% endorsed it. Which again is 97% but only that we’ve had some impact. Which could mean as little as accepting the “urban heat island” effect. A far better question would be how many of the studies said we caused most of it.
Amazingly, we know. Buried deep in the paper is the figure: 64. Not 64%. 64 papers. Out of nearly 12,000. Half a percent, rather short of 97%. And it gets worse. Climatologist David Legates actually read those 64 papers and found that 23 didn’t say what the Australian team claimed. The only danger here is to scientific integrity.
There’s more where that came from. But not much. Just a handful of papers that show considerable agreement on the uncontroversial claims that the Earth has warmed since Queen Victoria reigned and that humans had some impact. No manmade, and no crisis… except people yelling insults about “settled science” on the basis of frankly rather obvious statistical trickery.
If politicians and journalist are that carelessly and sanctimoniously wrong about a central claim in the dispute, it’s fair to ask what else they’ve got wrong. And that’s exactly what we’re doing at the Climate Discussion Nexus.