Carbon emissions from the Brazilian Amazon are increasingly dominated by forest fires during extreme droughts rather than by emissions from fires directly associated with the deforestation process, according to a study in Nature Communications. The authors suggest that recurrent 21st century droughts may undermine achievements in reducing emissions from deforestation in this region.

Luiz Aragao and colleagues use satellite data and greenhouse gas inventories to assess drought impacts on fire incidence and associated carbon emissions between 2003 and 2015 in the Brazilian Amazon. The authors find that despite a 76% decline in deforestation rates over the past 13 years, fire incidence increased by 36% during the 2015 drought compared to the preceding 12 years. They estimate that emissions from forest fires alone are more than half those from old-growth forest deforestation during drought years.

The authors argue that carbon emission inventories used for developing policies need to take into account drought-related forest fire emissions separately to those associated with the deforestation process.