Current investigations on global N₂O emissions and reductions: Prospect and outlook

Global nitrous oxide (N₂O) emissions merit scrutiny, because N₂O is the third most important greenhouse gas for global warming and the predominant ozone-depleting substance in this century. Here we recapitulate global natural and anthropogenic N₂O sources, comprehensively depict global sectoral human-induced N₂O emissions by country, thoroughly survey all existing approaches for mitigating human-induced N₂O emissions, preview the economic costs and social benefits from abating N₂O emissions, and summarize roadblocks for achieving its emission reductions. From 1970 to 2018, the annual global anthropogenic N₂O emissions increased by 64%-about 3.6 teragrams (Tg); agricultural sources primarily accounted for 78% of this increment. We find the social benefits from reducing N₂O emissions override the economic costs for abatements, only except precision farming for agricultural sources and replacement by Xe for anesthetic, thus justifying the motivation for crafting policies to limit its emissions. Net zero N₂O emissions cannot be achieved via applying current technologies and breeding N₂O-reducing microbes is a potential method to accrue N₂O sinks.