This study quantifies the increase in nitrous oxide (N₂O) emissions from global lakes and reservoirs since the pre-industrial era. 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, despite covering only 36% of the total surface area, contributed 55% of total N₂O emissions in the 2010s, highlighting their significant role in N₂O emissions. When combined with riverine emissions, global inland water N₂O emissions in the 2010s were 319.6 ± 58.2 Gg N yr⁻¹, indicating a global emission factor of 0.051% for inland water N₂O emissions relative to agricultural nitrogen applications. The study provides country-level emission factors (ranging from 0 to 0.341%) to improve national greenhouse gas emission inventories. N₂O is a potent greenhouse gas with a warming potential 273 times that of CO₂ over a 100-year period and contributes to stratospheric ozone destruction. Nitrogen processes in inland waters are critical components of the global nitrogen cycle and contribute significantly to N₂O emissions through nitrification and denitrification. Previous studies have assessed N₂O emissions from inland waters, but global estimates remain weakly constrained, particularly for lentic systems. Human activities have increased anthropogenic nitrogen loads transported to lentic systems, significantly contributing to N₂O emissions. However, previous estimates vary widely, and the use of constant emission factors in emission inventories fails to capture spatial variability. The study developed a dynamic mechanistic model to simulate N₂O emissions from lentic systems, incorporating terrestrial-aquatic interactions. The model was validated against observations, showing good performance with R² values exceeding 0.6 and Nash-Sutcliffe efficiency coefficients exceeding 0.5. The model revealed that N₂O emissions from lentic systems increased significantly from the pre-industrial period to the 2010s, with small lentic systems showing a greater response to environmental changes. Agricultural nitrogen additions were the dominant driver of N₂O emissions, contributing up to 60% of increased N₂O emissions in certain regions. Elevated atmospheric CO₂ concentrations had a negative effect on N₂O emissions by inhibiting terrestrial N loss to lentic systems. The study also estimated global inland water N₂O emissions, finding them to be 319.6 ± 58.2 Gg N yr⁻¹ in the 2010s, which falls within the range of previous estimates. The study highlights the importance of small lentic systems in the N cycle of inland water systems and theirThis study quantifies the increase in nitrous oxide (N₂O) emissions from global lakes and reservoirs since the pre-industrial era. 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, despite covering only 36% of the total surface area, contributed 55% of total N₂O emissions in the 2010s, highlighting their significant role in N₂O emissions. When combined with riverine emissions, global inland water N₂O emissions in the 2010s were 319.6 ± 58.2 Gg N yr⁻¹, indicating a global emission factor of 0.051% for inland water N₂O emissions relative to agricultural nitrogen applications. The study provides country-level emission factors (ranging from 0 to 0.341%) to improve national greenhouse gas emission inventories. N₂O is a potent greenhouse gas with a warming potential 273 times that of CO₂ over a 100-year period and contributes to stratospheric ozone destruction. Nitrogen processes in inland waters are critical components of the global nitrogen cycle and contribute significantly to N₂O emissions through nitrification and denitrification. Previous studies have assessed N₂O emissions from inland waters, but global estimates remain weakly constrained, particularly for lentic systems. Human activities have increased anthropogenic nitrogen loads transported to lentic systems, significantly contributing to N₂O emissions. However, previous estimates vary widely, and the use of constant emission factors in emission inventories fails to capture spatial variability. The study developed a dynamic mechanistic model to simulate N₂O emissions from lentic systems, incorporating terrestrial-aquatic interactions. The model was validated against observations, showing good performance with R² values exceeding 0.6 and Nash-Sutcliffe efficiency coefficients exceeding 0.5. The model revealed that N₂O emissions from lentic systems increased significantly from the pre-industrial period to the 2010s, with small lentic systems showing a greater response to environmental changes. Agricultural nitrogen additions were the dominant driver of N₂O emissions, contributing up to 60% of increased N₂O emissions in certain regions. Elevated atmospheric CO₂ concentrations had a negative effect on N₂O emissions by inhibiting terrestrial N loss to lentic systems. The study also estimated global inland water N₂O emissions, finding them to be 319.6 ± 58.2 Gg N yr⁻¹ in the 2010s, which falls within the range of previous estimates. The study highlights the importance of small lentic systems in the N cycle of inland water systems and their