Global warming threat seen in fertile soil of northeastern U.S. forests

Vast stores of carbon in U.S. forest soils could be released by rising global temperatures, according to a study by UC Irvine and other researchers in a recent online edition of Proceedings of the National Academy of Sciences.

The scientists found that heating soil in Wisconsin and North Carolina woodlands by 10 and 20 degrees increased the release of carbon dioxide by up to eight times. They showed for the first time that most carbon in topsoil is vulnerable to this warming effect.

"We found that decades-old carbon in surface soils is released to the atmosphere faster when temperatures become warmer," said lead author Francesca Hopkins, a doctoral researcher in UCI's Earth system science department. "This suggests that soils could accelerate global warming through a vicious cycle in which human-made warming releases carbon from soils to the atmosphere, which, in turn, would warm the planet more."