Dino-dooming asteroid impact created a chilling sulfur cloud

The asteroid collision that may have doomed the dinosaurs 66 million years ago really stank. A new analysis of gases released from vaporized rocks at the impact site in modern-day Mexico suggests that the smashup released up to three times more smelly, climate-cooling sulfur than previously believed.

The Chicxulub impact spewed about 325 billion tons of sulfur and 425 billion tons of carbon dioxide into the air, researchers report October 31 in Geophysical Research Letters.

This relatively modest release of CO₂ might have contributed to long-term planetary warming. But the massive cloud of sulfurous gas would have more immediately blocked out the sun, the researchers suggest, plunging the planet into a dark Narnia-style winter that was colder and longer than previously thought. That could help explain why so many of Earth’s plants and animals went extinct around this time, even those living nowhere near the impact crater (SN: 2/4/17, p. 16).

The new study suggests that the impact may have released around three times as much sulfur and much less carbon dioxide compared with previous estimates from 20 years ago. The new calculations incorporate a better understanding of the meteor’s angle of impact, the composition of the rocks and how much gas would make it high enough into the atmosphere to influence climate.