24 August 2010, By JOHN COLLINS RUDOLF

Earth’s Plant Growth Fell Because of Climate Change, Study Finds
Drought linked to climate change has reversed a decades-long trend of increased global plant growth, according to a new analysis of NASA satellite data.

“Earth has done an ecological about-face,” a NASA statement said. “Global plant productivity that once flourished under warming temperatures and a lengthened growing season is now on the decline, struck by the stress of drought.”

Research over the past two decades had shown terrestrial plant growth on the rise, with higher temperatures and longer growing seasons linked to a 6 percent increase in global plant productivity from 1982 to 1999. Between 2000 and 2009, terrestrial plant growth declined by 1 percent.

“This is a pretty serious warning that warmer temperatures are not going to endlessly improve plant growth,” Steven Running, a biologist at the University of Montana in Missoula and co-author of the report, said in the NASA statement.

The researchers found that high latitude ecosystems in the Northern Hemisphere continued to benefit from longer growing seasons and higher temperatures, but that this increased productivity was offset by severe warming-associated drought in the southern hemisphere.

“We see this as a bit of a surprise, and potentially significant on a policy level because previous interpretations suggested global warming might actually help plant growth around the world,” Dr. Running said.

The study was published in the journal Science.