This study examines the impact of environmental changes on nitrous oxide (N₂O) emissions from global lentic systems (lakes and reservoirs) since the pre-industrial era. The results show that global lentic systems emitted 64.6 ±12.1 Gg N₂O-N yr⁻¹ in the 2010s, a 126% increase since the 1850s. Small lentic systems, which contribute 55% of total N₂O emissions despite comprising only 36% of the total surface area, showed a 133% increase in N₂O emissions from 1850 to 2010. The study also highlights the significant role of agricultural activities in increasing N₂O emissions, with a global mean emission factor (EFₐg) of 0.051% for agricultural N₂O emissions from inland waters. The research emphasizes the importance of small lentic systems in mitigating N₂O emissions and provides country-level EFₐg values to improve national greenhouse gas emission inventories. The study uses a dynamic land ecosystem model (DLEM-TAC) to simulate N₂O emissions, incorporating terrestrial-aquatic processes and validating the model with observed data.This study examines the impact of environmental changes on nitrous oxide (N₂O) emissions from global lentic systems (lakes and reservoirs) since the pre-industrial era. The results show that global lentic systems emitted 64.6 ±12.1 Gg N₂O-N yr⁻¹ in the 2010s, a 126% increase since the 1850s. Small lentic systems, which contribute 55% of total N₂O emissions despite comprising only 36% of the total surface area, showed a 133% increase in N₂O emissions from 1850 to 2010. The study also highlights the significant role of agricultural activities in increasing N₂O emissions, with a global mean emission factor (EFₐg) of 0.051% for agricultural N₂O emissions from inland waters. The research emphasizes the importance of small lentic systems in mitigating N₂O emissions and provides country-level EFₐg values to improve national greenhouse gas emission inventories. The study uses a dynamic land ecosystem model (DLEM-TAC) to simulate N₂O emissions, incorporating terrestrial-aquatic processes and validating the model with observed data.