Arid areas absorb unexpected amounts of carbon

Eric Sorensen in the WSU News: Researchers led by a Washington State University biologist have found that arid areas, among the biggest ecosystems on the planet, take up an unexpectedly large amount of carbon as levels of carbon dioxide increase in the atmosphere. The findings give scientists a better handle on the earth’s carbon budget – how much carbon remains in the atmosphere as CO2, contributing to global warming, and how much gets stored in the land or ocean in other carbon-containing forms.

“It has pointed out the importance of these arid ecosystems,” said R. Dave Evans, a WSU professor of biological sciences specializing in ecology and global change. “They are a major sink for atmospheric carbon dioxide, so as CO2 levels go up, they’ll increase their uptake of CO2 from the atmosphere. They’ll help take up some of that excess CO2 going into the atmosphere. They can’t take it all up, but they’ll help.”

The findings, published in the journal Nature Climate Change, come after a novel 10-year experiment in which researchers exposed plots in the Mojave Desert to elevated carbon-dioxide levels similar to those expected in 2050. The researchers then removed soil and plants down to a meter deep and measured how much carbon was absorbed. “We just dug up the whole site and measured everything,” said Evans.

...The work addresses one of the big unknowns of global warming: the degree to which land-based ecosystems absorb or release carbon dioxide as it increases in the atmosphere. ...Overall, said Evans, rising CO2 levels may increase the uptake by arid lands enough to account for 4 to 8 percent of current emissions....

The Cima Dome landscape in the Mojave National Preserve in California, shot by Stan Shebs, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license