What we’re doing to the Earth has no parallel in 66 million years, scientists say
If you dig deep enough into the Earth’s climate change archives, you hear about the Palaeocene-Eocene Thermal Maximum, or PETM. And then you get scared. This is a time period, about 56 million years ago, when something mysterious happened — there are many ideas as to what — that suddenly caused concentrations of carbon dioxide in the atmosphere to spike, far higher than they are right now. The planet proceeded to warm rapidly...