Mass extinction by giant CO2 geysers

A vast reservoir of carbon is stashed beneath the Earth's crust and could be released by a major volcanic eruption, unleashing a mass extinction of the kind that last occurred 200 million years ago, German geologists report.

Researchers know that carbon is stored in the mantle, a layer of plastic-like rock beneath Earth's fragile crust, said Hans Keppler of the Institute of Sciences at Germany's University of Tuebingen, whose report appears in today's issue of Nature.

Exactly how much is down there is unknown. Most estimates, drawn from analyses of gases emerging from the mantle, suggest the store is many times more than all the carbon in the Earth's atmosphere, soil and sea combined.

The concern is that if just a part of this gigantic reservoir is quickly released as carbon dioxide, or CO2, that could create a runaway greenhouse effect. The CO2-soaked atmosphere would store up heat from the sun, shrivelling plant life and destroying species along the food chain.

"The [mantle] reservoir is just gigantic compared with anything that we have on the Earth's surface," said Keppler.

Posted by David on July 25, 2003 1:20 PM