June 2, 2009

Warming arctic may spew carbon releases

As frozen arctic soil thaws due to climate change, U.S. scientists say bacteria will break down large amounts of carbon, sending it into the atmosphere.

Although plants will initially proliferate, nurtured by balmier conditions and an increasing abundance of the greenhouse gas they depend on for growth, University of Florida researchers said they don't expect plant growth will be able to blunt the carbon release.

At first, with the plants offsetting the carbon dioxide, it will appear everything is fine, but actually this conceals the initial destabilization of permafrost carbon, said Associate Professor Ted Schuur. But it doesn't last, because there is so much carbon in the permafrost that eventually the plants can't keep up.

Schuur said most of the approximately 5 million square miles of permafrost in Alaska, Canada, Siberia and parts of Europe will eventually produce in the range of 1 billion tons of carbon annually.

It is not an option to be putting insulation on top of the tundra, Schuur said. If we address our own emissions, either by reducing deforestation or controlling emissions from fossil fuels, that's the key to minimizing the changes in the permafrost carbon pool.

The study is reported in the journal Nature.