Global warming effects of cropland expansion by reduction of biogenic secondary organic aerosols

Cropland expansion has been the most significant global land use change since industrialization. However, assessments of radiative forcing from land use change have overlooked the secondary organic aerosol (SOA) radiative effects of cropland expansion. Sensitivity experiments using an Earth system model with cutting-edge SOA processes reveal a ~10% decrease in biogenic SOA burden due to cropland expansion since industrialization, weakening SOA's scattering effect on radiation and cloud formation, resulting in a 146 mW m-2 decline in its cooling effect, equivalent to 8% of CO2-induced warming since industrialization. This effect is projected to increase by approximately half under future climate warming and reduced emissions. Policies addressing food security and climate change should account for the radiative impact of biogenic SOA from cropland expansion.