The global nitrous oxide budget revisited

We present an update of the global budget of atmospheric nitrous oxide (N2O) that accounts for recent revisions in estimates of global emissions. Most importantly, new estimates of N2O emissions from agriculture and from oceans and a surface sink of N2O have been included. Our estimates confirm that current food production is the largest anthropogenic source of N2O. However, its relative share in total anthropogenic emissions (about 60%) is smaller than in earlier studies (almost 80%). We estimate past trends in global emissions of N2O and use these as input to a simple atmospheric box model to calculate trends in atmospheric N2O concentrations for the period 1500–2006. We show that our revised estimates for global emissions of N2O are consistent with observed trends in atmospheric concentrations.