Drought is killing off trees in Brazil's fragile Amazon rain forest and depleting the region's carbon reservoirs -- an ecological double-whammy with devastating implications, according to a study published Thursday.

Researchers said the total impact of the drought was an additional five billion tonnes of carbon dioxide in the atmosphere -- more than the combined annual emissions of Europe and Japan.

The research from more than 40 institutions around the world was gathered during the particularly harsh 2005 drought, which had a severe impact on the flora of the Amazon.

The drought that year dramatically reversed decades of carbon absorption, the researchers said.

Labels: carbon, climate