8.4 Nitrous Oxide (Ch. 35)

Nitrous oxide emissions are the third largest driver of climate change and the single greatest threat to the stratospheric ozone layer. They accounted for approximately 5% of total U.S. GHG emissions in 2015 (measured in CO2eq). Key sources of nitrous oxide include agricultural soil and manure management, stationary and mobile combustion, and industrial processes such as adipic and nitric acid production. These sources account for 95% of U.S. nitrous oxide emissions. EPA estimates that U.S. nitrous oxide emissions will increase approximately 18.5% over 2015 levels by 2030, and these increases will come primarily from the agricultural sector. The DDPP reports conclude that nitrous oxide emissions should be reduced by at least 70 million tons CO2eq in 2050 relative to a business-as-usual baseline to achieve an overall net GHG emission reduction of 80% below 1990 levels by 2050. The chapter explains how existing legal pathways or new legal mechanisms could be used to attain and even exceed this reduction target.