Regional Fire Dynamics and Its Contributions to Carbon Flux Variability in South Asia

Forest fire has a significant impact on the regional carbon budget, the ecosystem and public health. We analyzed 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 event that unfolded in February, March, and April (FMA) of 2021. We find high burned areas (5,000–10,000 km2), and fire carbon emissions (0.3–4 TgC/season) across these regions in FMA, 2021 as compared to a climatological mean from 2010–2020. Each of the three regions show 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 (GPP). In Region–2, human activities, likely cropland burning, contributed to forest fire. In Region–3, the scattered distribution of burned areas suggests human activity is the likely cause of forest fire. During FMA, 2021, fire emission in Region–1 (~4 TgC) were almost twice the fossil fuel emissions (~2.2 TgC), while in Region–2 (~3.8 TgC), it remained below fossil emissions (~16 TgC). In both regions, forests and croplands contributed equally to fire emissions. In Region–3, fire emissions exceeded fossil 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 critical role of forest fires in the carbon budget, ecosystem and the need for better forest carbon management.