Rate of atmospheric carbon dioxide rise unprecedented

Human activity dwarfs fastest increase since time of dinosaurs, study finds

ocean sediment cores

CLIMBING CARBON  The rate of extra carbon currently entering the atmosphere is unmatched in at least 66 million years. Not even a massive outpouring of carbon 56 million years ago (recorded in this ocean sediment core as the 25-centimeter-long red band) comes close, a new study suggests. 

James Zachos

MONTREAL — Humans are dumping extra carbon into the atmosphere at a rate unprecedented since at least the time the dinosaurs went extinct about 66 million years ago, new research suggests.