This estimate is larger than in AR5 (WGI, 6.4.3) due to a larger estimated effect of nitrogen deposition on soil N 2O emissions and the explicit consideration of the role of anthropogenic nitrogen in determining inland water and estuary emissions.Based on bottom-up estimates, anthropogenic emissions from agricultural nitrogen use, industry and other indirect effects have increased by 1.7 (1.0 to 2.7) TgN yr–1 between the decades 1980– 1989 and 2007–2016, and are the primary cause of the increase in the total N 2O source