Nitrous Oxide: No Laughing Matter for the Climate and Ozone Challenge
By
Climate Interactive
December 11, 2024
While carbon dioxide (CO2) and methane (CH4) dominate climate discussions, nitrous oxide (N2O) received elevated attention at COP29 in Baku, Azerbaijan, with the launch of UNEP’s Global Nitrous Oxide Assessment. Nitrous oxide, also known as laughing gas, is a greenhouse gas often related to industrial fertilizer use. The impact on climate change and ozone depletion from N2O demands urgent action. Here’s what the latest research—and En-ROADS scenarios—reveal about N2O’s role and solutions.
The Importance of N2O
- N2O ranks third, after CO2 and CH4, as a key greenhouse gas driving climate change. It occurs in much smaller quantities than CO2, yet it is 273 times more potent than CO2 and persists in the atmosphere for more than a century.
- N2O is also the largest contributor to ozone depletion, yet it remains unregulated by the Montreal Protocol on ozone-depleting substances.
Key Insights from En-ROADS
Human activities have increased N2O emissions by 40% since 19801, with agriculture contributing 70% of anthropogenic sources in 2023 (see the yellow wedge in the “N2O Emissions by Source” graph). N2O emissions in agriculture are mostly related to fertilizer use and manure.
Using En-ROADS to simulate ambitious mitigation policies shows that we could avoid a cumulative 235 Gt CO2e emissions by 2100, which aligns closely with UNEP’s estimate.
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Emissions avoided were calculated by comparing the difference between the N2O emissions in the
“Greenhouse Gas Net Emissions by Gas” graph in this Reduction
Scenario
versus the
Baseline, using the
“Copy Data to Clipboard” graph feature.
This reduction is equivalent to more than six years of fossil fuel emissions, with 2023 fossil fuel CO2 emissions totaling 35 Gt CO2 (as shown in the “CO2 Emissions from Fossil Fuels” graph). N2O reductions complement broader strategies to cut CO2 and methane, helping to achieve global targets of limiting temperature well below 2°C.
Areas for action
En-ROADS allows you to experiment with ambitious N2O policies alongside other climate actions. Test scenarios, see their impacts in real time, and understand how N2O mitigation fits into a broader climate strategy.
The pathway forward is clear on N2O action:
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Improve agricultural practices: Optimized fertilizer application, enhanced manure management, and dietary shifts can address up to 70% of N2O emissions by 2050, compared to the Baseline (Scenario).
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Scale up industrial abatement: Proven technologies can reduce industrial N2O emissions by 90% by 2040, especially in nylon and other chemical production. Explore the settings in the advanced view of the Waste and Leakage slider (Scenario).
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Tackle waste emissions: Reduce N2O emissions from landfills and wastewater through waste management and decreasing total waste by reducing consumption and recycling (Scenario).
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Cut fossil fuel and wood burning: Add a carbon price, fossil fuel taxes, or increase energy efficiency to address N2O emissions from energy (Scenario).
What’s already being done?
Recent efforts provide a glimpse of progress:
- Facilities in China are expected to reduce emissions by 45 million metric tons CO2e annually, which represents nearly 10% of global N2O emissions from industry.2
- The U.S. and China, which account for nearly 80% of industrial N2O emissions, have committed to collaboration, leveraging technologies capable of reducing emissions by up to 99%.3
By including N2O in climate and ozone policies, we can tackle a hidden but critical challenge, helping both the climate and the ozone layer, as well as improving air and water quality, protecting biodiversity, and enhancing human health.
