Global NO emissions from our planet: Which fluxes are affected by man, and can we reduce these?

In some places, NO emissions have doubled during the last 2-3 decades. Therefore, it is crucial to identify NO emission hotspots from terrestrial and aquatic systems. Large variation in NO emissions occur in managed as well as in natural areas. Natural unmanaged tropical and subtropical wet forests are important NO sources globally. Emission hotspots, often coupled to human activities, vary across climate zones, whereas NO emissions are most often a few kg N ha year from arable soils, drained organic soils in the boreal and temperate zones often release 20-30 kg N ha year. Similar high NO emissions occur from some tropical crops like tea, palm oil and bamboo. This strong link between increased NO emissions and human activities highlight the potential to mitigate large emissions. In contrast, water where oxic and anoxic conditions meet are NO emission hotspots as well, but not possible to reduce.