Proc. Natl Acad. Sci. USA 105, 9439—9444 (2008)

Despite growing international concern about the future of the world's rainforests, the rate of tropical forest clearance has not slowed.

A team used a combination of low- and high-resolution satellite data sets to quantify forest clearing in the humid tropics. Using a probability-based approach blending satellite data retrieved from NASA's Terra and Landsat missions, Ruth DeFries of the University of Maryland in College Park and her colleagues estimate that more than 27 million hectares of rainforest area — roughly 2.4% of the global rainforest cover — were cleared from 2000 to 2005.

The results suggest that tropical forest loss continues at rates roughly similar with those observed in the 1990s.