How dangerous is climate change? A 250 mn-year-old event may hold clues

In some ways, the planet's worst mass extinction - 250 million years ago, at the end of the Permian Period - may parallel climate change today

Some 252 million years ago, Earth almost died.In the oceans, 96 percent of all species became extinct. It’s harder to determine how many terrestrial species vanished, but the loss was comparable.

This mass extinction, at the end of the Permian Period, was the worst in the planet’s history, and it happened over a few thousand years at most — the blink of a geological eye.

On Thursday, a team of scientists offered a detailed accounting of how marine life was wiped out during the Permian-Triassic mass extinction. Global warming robbed the oceans of oxygen, they say, putting many species under so much