The FAO's Global Nitrous Oxide Assessment presents a comprehensive evaluation of Nitrous oxide (Nâ‚‚O) emissions, their drivers, and mitigation strategies within agri-food systems. Nâ‚‚O, a potent greenhouse gas (GHG) and super pollutant, drives 10% of global warming (~0.1°C) and is the leading ozone-layer-depleting emission. Predominantly from agriculture (synthetic fertilizers and manure), its emissions have risen 40% since the Green Revolution in the 1980s and could increase 30% by 2050 without intervention. Agriculture contributes 75% of emissions, with industrial and other sources like fossil fuel combustion and wastewater treatment accounting for the remainder.
Reducing Nâ‚‚O emissions by over 40% by 2050 through sustainable nitrogen management offers benefits for climate goals, ozone protection, air and water quality, food security, and ecosystem resilience. Effective measures include controlled-release fertilizers, soil-nitrogen testing, improved manure practices, and dietary shifts. Addressing regulatory, economic, and cultural barriers is crucial, with regions of excessive fertilizer use offering the greatest abatement potential while others require increased nitrogen-fixing inputs for food security. Additional reductions are achievable by improving wastewater treatment and limiting biomass burning and fossil fuel use.
Decarbonization measures, such as ammonia-based marine fuels and fertilized-crop biofuels, risk raising Nâ‚‚O emissions. Understanding trade-offs among GHGs is essential for improving technologies and crafting mitigation policies. Sustainable nitrogen management, aligned with agreements like the Paris Agreement and Global Biodiversity Frameworks, supports emissions reductions while advancing food security, clean water and air, as well as sustainable agriculture under the SDGs.
