Vegetation greening enhances global fire activity

Global terrestrial ecosystems have witnessed increased vegetation greenness ^1–3 and intensified fire regimes ^4–7 in many ecosystems worldwide, but the potential connections between them remain elusive. We quantify the impact of vegetation greening on global fire activity by examining changes in live and dead fine fuels based on multiple long-term satellite-based datasets. We show that, despite the recently observed human-driven decline in global burned area ⁸ , vegetation greening has led to an increase in global burned fraction at a rate of 0.014 ± 0.004% per year over 2001–2020. This amplifying effect is primarily driven by the increase in dead fine fuel (0.047 ± 0.009% per year), partially offset by the dampening effect of increased canopy live foliage (-0.018 ± 0.007% per year). Notably, current fire-vegetation models inaccurately represent the interactions between fire and greening, resulting in underestimations of fire responses to vegetation greening, particularly in arid and cold regions. Our findings highlight the widespread amplification of global fire activity caused by the ongoing trend of vegetation greening. They underscore the importance of considering this biogeochemical positive feedback in the land-climate system and support the efforts to mitigate its impact on ecosystems and societies.