Skywatch Special EditionPhoto: These two fossilized leaf bits come from a type of bean plant that migrated from the latitude of Louisiana to Wyoming 55 million years ago to escape a monster heat wave that dwarfs today's global warming.
Aug, 2006
WASHINGTON - It was one of the greatest calamities of all time: Something turned up the Earth's thermostat, touching off a monstrous heat wave that killed many animals and drove others far from their homes to seek cooler climes.
This catastrophe occurred 55 million years ago, after the age of the dinosaurs and long before humans appeared. But scientists warn that today's global warming means that it could be happening again.
The ancient hot spell, which lasted 50,000 to 100,000 years, goes by the unwieldy name of Paleocene-Eocene Thermal Maximum. It was caused by a sudden - in geological terms - doubling or tripling of carbon dioxide and other greenhouse gases in the atmosphere. Climate scientists say the result was a massive increase of 10 to 12 degrees Fahrenheit - even higher near the poles - above the prevailing temperature.
