The neglected disproportionate contributions of active fires in greenhouse gas emissions globally

The steeply rising greenhouse gas (GHG) emissions poses significant safety hazards to human society and global change, which was generally sourced from fires as well as fossil and bio fuels combustion. Since 2000, global carbon dioxide (CO₂) emissions from active fires have been approximately 25% of those from fossil fuels and land use change. Due to the complicated mechanisms of interactions between active fires and GHG emissions, the size, distribution, and changes of GHG emissions from active fires contributions exist wide differences. The contributions of active fires to GHG emissions and their discrepancies as well as driving mechanisms at the global scale remain poorly understood systematically. Here, we combine GHG emission, active fires, land cover, temperature, and population products (2003–2021) to quantificat the spatio-temporal features of fires-induced GHG emissions and possible drivers. Although the proportions of GHG emissions from active fires showed a descending tendency with fluctuation, the annually totality almost kept increasing since 2003. Among total 9.71 × 10⁵ million tons GHG emissions, active fires released approximately 20% (1.85 × 10⁵ million tons), and shows significant regional variability. Land cover, temperature, and population jointly regulated global disproportionate contributions of active fires in GHG emissions. Most areas, where GHG emissions from active fires obviously exceeded that from fossil and bio fuels combustion, were sparsely populated. Over 43% of GHG emission contributions from active fires were counted in Brazil, the Democratic Republic of Congo, Kazakhstan, Mainland of Southeast Asia, and Australia. Our findings emphasize the crucial contribution of active fires to global carbon emissions, particularly CO₂ emissions. Future efforts on global warming alleviation, carbon neutrality, GHG budgets, and sustainable development should take the impact of fire emissions into account.