Increased global nitrous oxide emissions from streams and rivers in the Anthropocene

Emissions of nitrous oxide (N 2 O) from the world’s river networks constitute a poorly constrained term in the global N 2 O budget 1, 2. This N 2 O component was previously estimated as indirect emissions from agricultural soils 3 with large uncertainties 4, 5, 6, 7, 8, 9, 10. Here, we present an improved model representation of nitrogen and N 2 O processes of the land–ocean aquatic continuum 11 constrained with an ensemble of 11 data products. The model–data framework provides a quantification for how changes in nitrogen inputs (fertilizer, deposition and manure), climate and atmospheric CO 2 concentration, and terrestrial processes have affected the N 2 O emissions from the world’s streams and rivers during 1900–2016. The results show a fourfold increase of global riverine N 2 O emissions from 70.4±15.4 Gg N 2 ON yr− 1 in 1900 to 291.3±58.6 Gg N 2 ON yr− 1 in 2016, although the N 2 O emissions started …