Fire decline in dry tropical ecosystems enhances decadal land carbon sink

The terrestrial carbon sink has significantly increased in the past decades, but the underlying mechanisms are still unclear. The current synthesis of process-based estimates of land and ocean sinks requires an additional sink of 0.6PgC yr(-1) in the last decade to explain the observed airborne fraction. A concurrent global fire decline was observed in association with tropical agriculture expansion and landscape fragmentation. Here we show that a decline of 0.20.1PgC yr(-1) in fire emissions during 2008-2014 relative to 2001-2007 also induced an additional carbon sink enhancement of 0.4 +/- 0.2PgC yr(-1) attributable to carbon cycle feedbacks, amounting to a combined sink increase comparable to the 0.6PgC yr(-1) budget imbalance. Our results suggest that the indirect effects of fire, in addition to the direct emissions, is an overlooked mechanism for explaining decadal-scale changes in the land carbon sink and highlight the importance of fire management in climate mitigation. p id=Par In recent history the amount of carbon captured by terrestrial systems has increased, but the processes driving this process has remained poorly constrained. Here the authors use a global carbon model to show that a decrease in wildfires has caused the land carbon sink to increase in the past few decades.