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Trees & Drought

August 7, 2015

Droughts are reducing the ability of trees to slow climate change.




Drought-stricken trees in the Southwestern U.S. (William Anderegg)

Droughts may diminish forests’ climate-saving powers. I’m Bob Hirshon and this is Science Update.

Trees help fight climate change by absorbing the greenhouse gas carbon dioxide as they grow. But in the journal Science, University of Utah ecologist William Anderegg writes that droughts are slowing tree growth significantly—and not just for a year or two, as was thought, but for up to four full years per event.

WILLIAM ANDEREGG (University of Utah):

What’s new about our study is that we were able to look at over a thousand forest sites and many different tree species and ecosystems and really see this as a pervasive widespread effect.


Anderegg says global warming will lead to more droughts that slow tree growth even further, reducing their CO2 absorption still more. That means countries must aggressively limit the release of CO2 into the atmosphere, because trees will become less able to remove what’s already there. I’m Bob Hirshon, for AAAS, the science society.