Frédéric Achard · Science 2002 · Observational remote-sensing monitoring study · n=?

Determination of Deforestation Rates of the World's Humid Tropical Forests

Cited 2011 times in the scientific literature.

Level 3 - non-randomized controlled study

Level 3 by design analogy (longitudinal observational remote sensing survey, non-clinical).

OpenAlex W2114892242 · doi:10.1126/science.1070656 · record verified 2026-08-30

What was done

Earth-observing satellite imaging from the Tropical Ecosystem Environment Observations by Satellite (TREES) research program was analyzed to assess changes in the world's humid tropical forest cover between 1990 and 1997.

What was found

Between 1990 and 1997, an estimated 5.8 ± 1.4 million hectares of humid tropical forest were lost per year, and an additional 2.3 ± 0.7 million hectares were visibly degraded annually. These measurements showed that the net rate of humid tropical forest cover change was 23% lower than the generally accepted baseline rate at the time.

Why it matters

Lower tropical deforestation estimates directly alter global carbon flux models, indicating that the missing terrestrial carbon sink was smaller than previously inferred.

Limits

The abstract does not disclose the specific satellite sensors used, image resolution, sampling grid, or regional breakdown of deforestation rates. Findings are limited strictly to humid tropical forests between 1990 and 1997 and do not cover dry tropical or temperate biomes.

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