Paris, July 25: 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 a kind that last occurred 200 million years ago, German scientists say.
Researchers have known for years that carbon is stored in the Earth's mantle, a layer of plasticky rock that lies beneath the planet's fragile crust. Exactly how much is down there is unknown. Most estimates, drawn from analyses of gases emerging from the mantle, say the store is many times more than all the carbon in the Earth's atmosphere, soil and sea combined.


The worry is that if just a part of this gigantic reservoir is quickly released as carbon dioxide (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," says Hans Keppler, a professor at the Institute of Sciences at Germany's University of Tuebingen.


Reporting in Nature, Keppler and his colleagues conducted an ambitious experiment aimed at finding whether mantle rock is a stable storage for CO2.


Most of the rock in the Earth's upper mantle is a crystalline silicate called olivine. Bureau Report