The beginning of the end: Part 1

Warming 'Wiped Out' Most Life 250 Million Years Ago

A slow process of climate warming rather than a comet or asteroid impact led to Earth's biggest mass extinction, according to research.

Scientists have found no evidence of a major impact around the time of the event, known as the "Great Dying," 250 million years ago.

They believe the extinction was the result of global warming due to volcanic eruptions and a drop in oxygen levels.

The findings provide an ominous glimpse of what can happen when the climate heats up over a long period.

In the case of the mass extinction at the end of the Permian period, the changes took millions of years.

The Great Dying wiped out 90 percent of marine species and nearly three-quarters of animals and plants on land.

Dr. Peter Ward, a paleontologist at the University of Washington in Seattle, who led the research, said: "Animals and plants both on land and in the sea were dying at the same time, and apparently from the same causes, too much heat and too little oxygen."

The scientists collected fossils in South Africa's Karoo Basin, and found a gradual, then sharp, decline in species population. However, there was no indication that a comet or asteroid struck the Earth at about this time. A later impact off the coast of Mexico is said to have ended the dinosaur reign 65 million years ago.

Dr. Ward's team, whose findings appear in the online edition of the journal Science, believes if an impact by a body from space was involved, it played only a small part.

"I think temperatures rose to a critical point. It got hotter and hotter until it reached a critical point and everything died. It was a double-whammy of warmer temperatures and low oxygen, and most life couldn't deal with it, " said Dr. Ward

• great, more bad news, and we all know the world is getting warmer
• afternoons are terrible these days in malaysia, i cant remember feeling like i was being burnt alive while walking in the sun when i was growing up.
• maybe i've got some memory loss due to walking under the sun too much, which would explain why i dont remember that.