"One of the most powerful ways to figure out how the Earth will respond to all the carbon dioxide we're putting into the atmosphere is to look back into the planet's history."

"Paleontologists have spent a lot of time trying to understand a time, more than 50 million years ago, when the planet was much hotter than it is today. They're finding that the news isn't all bad when you take the long view."

"About 10 million years after the dinosaurs died out, the Earth suffered another huge ecological shock: Carbon dioxide levels in the air soared and the oceans turned more acidic as carbon dioxide dissolved in the water and turned into carbonic acid. And that's happening again, thanks to our use of fossil fuels."