Seth Borenstein at the AP has written a perfectly good story on a study in Science that says that "aggressive acts like committing violent crimes and waging war become more likely with each added degree." And here's the money quote, further down in the story:
"The world will be a very violent place by mid-century if climate change continues as projected," said Thomas Homer-Dixon, a professor of diplomacy at the Balsillie School of International Affairs in Ontario.
"In war-torn parts of equatorial Africa, [the study] says, every added degree Fahrenheit or so increases the chance of conflict between groups— rebellion, war, civil unrest—by 11 percent to 14 percent," Borenstein writes. And the researchers parse their predictions even finer: In the U.S., "the formula says that for every increase of 5.4 degrees Fahrenheit, the likelihood of violent crime goes up 2 percent to 4 percent."
Borenstein mentions two other researchers who say these are important results, and he goes on to say that "experts who research war and peace were split in their reaction to the work."
Here's where it gets interesting. One of those experts is responsible for the "violent place" quote above. The other says that temperature "is only one factor in conflict." He goes on to say that factors that would lower conflict in the future include "positive changes in technology, economics, politics and health."
That addressed the question I had as soon as I read the predictions: Do the researchers really have this figured out so precisely that they can predict an increase of 2-4 percent with changes in temperature? With a different election outcome in the U.S. in 2000, we might not have gone to war with Iraq. Isn't it possible that a single election outcome can affect the likelihood of conflict far more than a change in temperature? I don't know; I'm asking.
Don't get me wrong; Borenstein's story was thorough and well reported. He included the skepticism that I'm relying on, in part, to raise this question. Others wrote the same story. I'm just wondering whether the stories were skeptical enough.
"Extraordinary claims require extraordinary evidence," the scientist and writer Carl Sagan once said. Claiming that a one-degree rise in Africa can boost conflict by 11 percent to 14 percent while a 5-degree rise in the U.S. boosts conflict by only 2-4 percent is an extraordinary claim. Claiming that temperature can predict changes in conflict despite other social changes is also an extraordinary claim.
Do these researchers have extraordinary evidence? From the copy I've read, I can't tell.