Mammoth dung, prehistoric goo may speed warming

By Dmitry Solovyov

DUVANNY YAR, Russia (Reuters) - Sergei Zimov bends down, picks up a handful of treacly mud and holds it up to his nose. It smells like a cow pat, but he knows better.

"It smells like mammoth dung," he says.

This is more than just another symptom of global warming.

For millennia, layers of animal waste and other organic matter left behind by the creatures that used to roam the Arctic tundra have been sealed inside the frozen permafrost. Now climate change is thawing the permafrost and lifting this prehistoric ooze from suspended animation.

But Zimov, a scientist who for almost 30 years has studied climate change in Russia's Arctic, believes that as this organic matter becomes exposed to the air it will accelerate global warming faster than even some of the most pessimistic forecasts.

"This will lead to a type of global warming which will be impossible to stop," he said.

When the organic matter left behind by mammoths and other wildlife is exposed to the air by the thawing permafrost, his theory runs, microbes that have been dormant for thousands of years spring back into action.

As a by-product they emit carbon dioxide and -- even more damaging in terms of its impact on the climate -- methane gas.