Fire Moderation in Southeast Asia Mitigates the Adverse Effects of Aerosols on Spring Green‐Up

Transboundary fire‐derived aerosols in Southeast Asia pose a persistent regional environmental challenge, with impacts extending beyond air quality to ecosystem function and carbon dynamics, yet their effects on seasonal phenology remain poorly understood. Here we use a coupled atmosphere‐air quality model, ridge regression, structural equation models and a scenario‐based random forest model to quantify the impacts of fire aerosol on spring green‐up date (GUD). Results show that during the period 2010 to 2022, fire emissions dominated regional aerosol optical depth (AOD), explaining 91.18% of its interannual variability. The region exhibited a warming and wetting trend advancing GUD, with pre‐GUD temperature controlling GUD in 57.82% of the area. Fire‐derived AOD delayed GUD through both direct and indirect meteorological effects, partially offsetting climate‐driven GUD advancement. Scenario simulations indicate that without the observed decline in fire‐derived AOD, the current GUD advance (−0.68 days/yr) would reverse to a slight delay (0.01 days/yr). These findings demonstrate that fire aerosols can counteract climate‐induced earlier GUD, underscoring the need to incorporate cross‐border aerosol forcing into ecosystem resilience and fire management assessments.