Two degrees Celsius.
That, according to broad scientific consensus, is how much global temperatures need to rise in order to trigger a severe international crisis. According to the climatologists behind the blog RealClimate, crossing the two-degree threshold “stands a strong chance of provoking drought and storm responses that could challenge civilized society, leading potentially to the conflict and suffering that go with failed states and mass migrations.”
The question is how long we have before such an outcome becomes inevitable. Climatologist Michael E. Mann, a professor at Pennsylvania State University, has come up with one possible answer: If his calculations are accurate, we have less time than you might think.
“If the world keeps burning fossil fuels at the current rate, it will cross a threshold into environmental ruin by 2036,” Mann wrote in Scientific American earlier this week.









