Global Nitrous Oxide Budget
Highlights

N₂O emissions from human activities have increased by 40% (3 million metric tons of N₂O per year) in the past four decades.

Agricultural production (due to the use of nitrogen fertilizers and animal manure) contributed 74% of the total anthropogenic N₂O emissions in the last decade.

N₂O accumulation in the atmosphere has accelerated in the last four decades, with growth rates over the past three years (2020-2022) higher than any previous observed year since 1980 when reliable measurements began, and about 30% higher than in the past decade.

The concentration of atmospheric N₂O reached 336 parts per billion in 2022 (the latest global data available), 25% above pre-industrial levels.

The observed atmospheric N₂O concentrations in the past decade have exceeded the most pessimistic illustrative future GHG trajectories used by the IPCC that lead to global mean temperatures well above 3°C by the end of this century.

For net-zero emission pathways consistent with the Paris Agreement (stabilizing global temperatures below 2°C from pre-industrial levels), anthropogenic N₂O emissions must decline by at least 20% relative to 2019 levels by 2050.

The top five country emitters by volume of anthropogenic N₂O emissions in 2020 were China (16.7%), India (10.9%), USA (5.7%), Brazil (5.3%), and Russia (4.6%).

The global ocean continues to be a source of N₂O and remains stable at about 7.4 million metric tons per year, with a large contribution from the global coastal oceans.

The EU, Japan and Korea have successfully reduced anthropogenic N₂O emissions over the past decades. However, even with measurable increases in nitrogen use efficiency in agriculture in some regions, emissions from direct fertilizer and manure application have slightly increased or remained stable. China's anthropogenic N₂O emissions have been declining for the past five years owing to increased nitrogen use efficiency.

Southern Africa and the Middle East have emissions from non-agricultural sources (industry, fossil fuel combustion and waste, biomass burning), which are comparable to, or higher, than the agricultural emissions, requiring different mitigation strategies.