Regional fire dynamics and its contributions to carbon flux variability in South Asia

Abstract Fires have a significant impact on the regional carbon budget, the ecosystem, and public health. We analyzed the fire dynamics and its impact on carbon flux across three fire prone regions in South Asia, Region-1 (southwestern Nepal, Uttarakhand), Region-2 (central India), and Region-3 (northeast India) from 2010 to 2021, with a focus on the significant fire season of February, March, and April (FMA) of 2021. We find high burned areas (5000–10 000 km 2 ), and fire carbon emissions (0.3–4 TgC season –1 ) across these regions in FMA, 2021, as compared to a climatological mean from 2010–2020. Each of the three regions shows distinct drivers that preceded the fires. In Region-1, snow-induced soil moisture deficits drive fire activity, leading to a subsequent decline in gross primary production . In Region-2, human activities, likely cropland burning, contributed to the forest fire. In Region-3, the scattered distribution of burned areas hints that human activity is the likely cause of the forest fire. During FMA, 2021, fire carbon emission in Region-1 (∼4 TgC) were almost twice of the fossil fuel emissions (∼2.2 TgC), while in Region-2 (∼3.8 TgC), it remained below fossil fuel emissions (∼16 TgC). In both regions, emissions from forests and croplands contributed equally to the total fire carbon emissions. In Region-3, fire carbon emissions exceeded fossil fuel emissions in 2012 (∼4.7 TgC), 2013 (∼6.18 TgC), and 2014 (∼9.75 TgC) but remained lower in 2021 (∼3.37 TgC), with most emissions originating from forests. This analysis highlights the critical role of forest fires in the carbon budget, the ecosystem and the need for better forest carbon management.