The Southeastern Amazon as a Carbon Source

node · earth · Eastern and southeastern Amazon Basin

The finding that part of the Amazon has stopped being a net absorber of carbon dioxide and become a net emitter, independent of any single drought year. Gatti and colleagues reported in 2021 on a programme of repeated vertical aircraft profiles flown over four sites across the basin through the 2010s - a method that samples the whole column of air over a large footprint rather than a plot or a tower, and therefore measures a region rather than a stand. The eastern basin, and the southeast in particular, emitted more carbon than it absorbed. The mechanism they describe is cumulative rather than sudden: that part of the basin has seen the largest clearance, the strongest dry-season warming and a lengthening dry season, and fire converts the loss into emissions directly. The northwest, wetter and largely intact, still absorbed. The importance of the result is that it separates two things usually run together - a drought year in which the forest temporarily releases carbon, and a region that has changed state.