More meteoric extinctions?

At least once in Earth's history, global warming ended quickly, and scientists have long wondered why.

Now researchers are reporting that the abrupt cooling -- which took place about 12,900 years ago, just as the planet was emerging from an ice age -- may have been caused by one or more meteors that slammed into North America.

That could explain the extinction of mammoths, saber-tooth tigers and maybe even the first human inhabitants of the Americas, the scientists report in Friday's issue of the journal Science.

Posted by David on January 11, 2009 9:07 PM