GLOBAL COOLING:

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.

Let’s hope this doesn’t happen again any time soon.