Amazon's 2005 drought created huge CO2 emissions

By Alister Doyle, Environment Correspondent

OSLO (Reuters) - A 2005 drought in the Amazon rainforest killed trees and released more greenhouse gas than the annual emissions of Europe and Japan, an international study showed on Thursday.

The report said rainforests from Africa to Latin America may speed up global warming if the climate becomes drier this century. Plants soak up heat-trapping carbon dioxide as they grow and release it when they die and rot.

"The Amazon forest was surprisingly sensitive to drought," said Oliver Phillips, a professor of tropical ecology at Leeds University in England who led the study by 68 scientists.

The experts estimated that the forest had been absorbing 2 billion tons of carbon dioxide a year on average since the 1980s but lost 3 billion in the 2005 drought, which killed trees and slowed growth.

"The total impact was an extra 5 billion tons of carbon dioxide in the atmosphere. That is more than the annual emissions of Europe and Japan combined," Phillips said of the study published in the journal Science.

SAVANNAH

Paradoxically, the forest's accumulation of carbon before 2005 may have been aided by global warming, which improved plant growth.

But the U.N. Climate Panel projected in a 2007 report that rising temperatures may cause more drought and "lead to gradual replacement of tropical forest by savannah" in the eastern Amazon by mid-century.