Spring biomass-burning aerosols intensify extreme climate and socioeconomic risks around the South China Sea

In order to investigate the radiative effects of the notably biomass burning aerosols (BBAs) emitted from Southeast Asia during spring on surrounding areas, we conducted sensitivity experiments using the WRF-Chem model. The results show that BBAs exerted profound radiative impacts on climate extremes and socioeconomic systems in two key regions around the South China Sea: droughts in Thailand and pre-summer extreme rainfall in Guangdong, China. In Thailand, BBAs suppressed precipitation and soil moisture, elevating drought risk and critically constraining the growth of second-crop rice. Historical analyses suggested that rice production were be declined if average daily rainfall less than 2.1 mm and an aerosol-doubling scenario might reduce 0.97 Mt of rice production, roughly equivalent to a loss of 6.4–12.9 billion THB. In Guangdong, BBAs markedly intensified extreme precipitation by regulating boundary-layer jets, substantially increasing the frequency and severity of rainfall extremes. Linking historical extremes with GDP growth revealed that aerosol doubling could have reduced growth by 4.2 (3.7–4.6) percentage points, with total economic losses reaching 339.5 (299.8–374.8) billion RMB. in losses. While mortality risks were projected to decline with socioeconomic development and disaster preparedness, the compounding effects of aerosols and climate variability underscore the urgent need to integrate air pollution control, agricultural adaptation, and flood-risk management into regional resilience strategies.