Spurred by increasing levels of atmospheric carbon dioxide, forests over the last two decades have become dramatically more efficient in how they use water, a Harvard study has found.
Studies have long predicted that plants would begin to use water more efficiently as atmospheric carbon dioxide levels rose. A research team led by Research Associate Trevor Keenan and Assistant Professor of Organismic and Evolutionary Biology Andrew Richardson, however, has found that forests across the globe are becoming more efficient than expected.
Using data collected from forests in the northeastern US and elsewhere around the world, Keenan and Richardson, found increases in efficiency larger than those predicted by even the most state-of-the-art computer models. The research, which was done in collaboration with researchers from the Harvard's Department of Earth and Planetary Sciences, the USDA Forest Service, Ohio State University, Indiana University, and the Karlsruhe Institute of Technology in Germany, is described in a July 10 paper in Nature.
"This could be considered a beneficial effect of increased atmospheric carbon dioxide," said Keenan, the first author of the paper. "What's surprising is we didn't expect the effect to be this big. A large proportion of the ecosystems in the world are limited by water they don't have enough water during the year to reach their maximum potential growth. If they become more efficient at using water, they should be able to take more carbon out of the atmosphere due to higher growth rates."
While increased atmospheric carbon dioxide may benefit forests in the short term, Richardson emphasized that the overall climate picture would remain grim if levels continue to rise.
"We're still very concerned about what rising levels of atmospheric carbon dioxide mean for the planet," Richardson cautioned. "There is little doubt that as carbon dioxide continues to rise and last month we ju
|Contact: Peter Reuell|