The methane is like a hangover that you can get over if you stop drinking,” said Raymond T. Pierrehumbert, a climate scientist at the University of Chicago and the author of a textbook on planetary atmospheres. “CO2 is more like lead poisoning — it sticks around, you don’t get rid of it, and it causes irreversible harm.”
Climate scientists long ago settled among themselves the question of whether human emissions of greenhouse gases are a problem, concluding that we are running some grave risks. But the field still features vigorous debate about how bad global warming will get, how quickly, and how to combat it.