Increased nitrous oxide emissions from global lakes and reservoirs since the pre-industrial era

Abstract

Lentic systems (lakes and reservoirs) are emission hotpots of nitrous oxide (N ₂O), a potent greenhouse gas; however, this has not been well quantified yet. Here we examine how multiple environmental forcings have affected N ₂O emissions from global lentic systems since the pre-industrial period. Our results show that global lentic systems emitted 64.6 ± 12.1 Gg N ₂O-N yr ⁻¹ in the 2010s, increased by 126% since the 1850s. The significance of small lentic systems on mitigating N ₂O emissions is highlighted due to their substantial emission rates and response to terrestrial environmental changes. Incorporated with riverine emissions, this study indicates that N ₂O emissions from global inland waters in the 2010s was 319.6 ± 58.2 Gg N yr ⁻¹. This suggests a global emission factor of 0.051% for inland water N ₂O emissions relative to agricultural nitrogen applications and provides the country-level emission factors (ranging from 0 to 0.341%) for improving the methodology for national greenhouse gas emission inventories.

Abstract

Modeling shows that N ₂O emissions from global lakes and reservoirs have doubled since the pre-industrial era, this was mainly caused by widespread agricultural nitrogen application.