Nitrous Oxide
Nitrous Oxide (N2O) is now the most significant ozone-depleting substance (ODS) and is projected to remain so throughout the 21st century. It is also the third most important greenhouse gas (GHG) and is 273 times more potent than carbon dioxide (CO2) on a tonne for tonne basis over a 100-year period. The vast majority of our N2O emissions come from agriculture, largely through the overuse of fertilisers, with wastewater, biomass burning, transport and industrial emissions also contributing significantly to the total human-caused output. Largely unchecked, N2O emissions simultaneously undermine global efforts to reverse depletion of the ozone layer under the Montreal Protocol, and to limit global surface temperature increases to 1.5°C under the Paris Climate Agreement.