Quantifying greenhouse gas emissions from landscape fires due to the Russo–Ukrainian War and the impact on the carbon sequestration capacity of forests

Vegetation acts as an essential land-based carbon sink, which can be affected by military conflicts and wars through landscape fires that can cover large territories and will lead to additional greenhouse gas (GHG) emissions into the atmosphere. To investigate this impact, we spatially analyzed the effect of the ongoing Russo–Ukrainian War on the GHG emissions from landscape fires and determined the change to the carbon sequestration capacity of the forests. Using remotely sensed data from 2022–2023, we first identified the fire perimeters in the territory of Ukraine. We then classified the burned areas into coniferous and deciduous forests, croplands, and other landscapes, and evaluated the distribution of the fires according to their intensity based on the differenced normalized burn ratio. We used several fire weather condition indices and calculated the attribution factor to identify the share of fires that were war related and were thus not caused by natural factors or human activity that would be typical in times of peace. We estimated the war-related biomass losses during the first two years of the war, considering the landcover type, the species and the age structure of the forest stands, the fire intensity, and the biomass content. The corresponding GHG emissions in the immediate term were estimated to be 9.08 Mt carbon dioxide equivalent (CO₂e), with a relative uncertainty of ±46% (95% confidence interval). The estimated future (long-term) biomass losses due to current forest fires and their corresponding GHG emissions were calculated to be 16.86 Mt CO₂e (±21%). Finally, losses in the carbon sequestration capacity of the burned forests during the first five years following the landscape fires were estimated to be 2.9 Mt CO₂e.