Limits of climate change

Earth’s climate has undergone some big changes, from global volcanism to planet-­cooling ice ages. And yet life, for the last 3.7 billion years, has kept on beating.

Now a study by MIT researchers confirms something long suspected: that a “stabilizing feedback” mechanism keeps global temperatures within a habitable range. The likely key is the slow and steady weathering of silicate rocks, which involves chemical reactions that draw carbon dioxide out of the atmosphere and into ocean sediments. 

The researchers applied a mathematical analysis to data that record changes in average global temperatures over the last 66 million years. They found that there appears to be a consistent pattern in which temperature swings are dampened over hundreds of thousands of years, similar to the time scales over which silicate weathering is predicted to act.

“On the one hand, it’s good because we know that today’s global warming will eventually be canceled out through this stabilizing feedback,” says graduate student Constantin Arnscheidt, a coauthor of the study. “But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.”