Satellite Deforestation Monitoring

node · earth · Legal Amazon

The instrument that turned Amazon deforestation from an argument into a measurement, and the distinction inside it that most public reporting collapses. PRODES is the annual accounting system: wall-to-wall mapping of clear-cut deforestation across the Legal Amazon using Landsat-class optical imagery, with a minimum mapped patch size of a few hectares, over a reference year running from August to July. It is deliberately conservative - it counts only complete removal of forest cover, it is validated by interpreters, and it is published months after the year it describes. DETER is the enforcement system: much faster, lower resolution, issuing alerts within days so that inspectors can be sent, and explicitly not the official rate. Confusing the two produces most of the spurious controversies about Brazilian deforestation figures, because a DETER alert total and a PRODES annual rate are different quantities. Independent series exist alongside them - NGO-run alert systems and global forest-change products - and they disagree with PRODES and with each other, because each encodes a different definition of what counts as forest and what counts as loss.