United Kingdom's Sources of N2O Emissions
Key Insights
Agriculture Leads The Profile
Agriculture dominates the United Kingdom's nitrous oxide picture, accounting for roughly two‑thirds of emissions. Levels were modest early on, then climbed rapidly during the post‑war era, peaking at around 30 megatonnes by the late 1980s. Since then, agricultural emissions have trended down, easing to roughly 20 megatonnes, yet they remain by far the largest source.
Industry Spiked, Then Fell
Industrial emissions were minimal before mid‑century, rose through the post‑war decades, and briefly surged in the early 1970s before entering a long decline. They now sit at roughly 2 megatonnes, far below their mid‑ to late‑20th‑century highs. "Other" sources held steady for much of the 20th century and have fallen steadily since around 1990, now well under 1 megatonne.
Energy Plateau And Gradual Decline
Energy‑related emissions grew into the mid‑20th century and hovered in the high‑2 megatonne range from the late 1960s to the mid‑1990s. Since then they have edged down to just under 2 megatonnes. Waste remains minor relative to agriculture but has inched upward since the mid‑1990s to around 2 megatonnes.
Current Trajectory And Priorities
Among major sources, the trend is broadly downward: agriculture, energy, industry, and other are all lower than their late‑20th‑century levels. Progress is real but gradual-especially in agriculture-so deeper cuts there will drive the overall trajectory. Continued declines in energy and industry, alongside sustained reductions in other sources, would reinforce the UK's downward momentum.
Background
The chart shows a national breakdown by source of the yearly nitrous oxide (N2O) emissions from human activities and processes, expressed as weight in megatonnes (Mt). Human-induced emissions are the main driver of the increasing atmospheric nitrous oxide that is warming our planet. The sources of human nitrous oxide emissions are
- Agriculture
- Energy
- Industry
- Waste
- Other
Agriculture
Emissions related to agriculture are mainly from the use of synthetic fertilizers and manure management.
Synthetic fertilizer, used for agricultural processes, contains a lot of nitrogen. That nitrogen in the soil reacts and causes considerable N2O emissions. The use of excess fertilizer, meaning more fertilizer than the plants can use to grow, causes even higher relative emissions. Applying the right amount of fertilizer at the right time can reduce N2O emissions. There are many technical solutions to reduce emissions while keeping, or even increasing, agricultural yields.
When manure is left on the field or otherwise managed in dry processes, it emits considerable amounts of nitrous oxide. Manure can be managed by wet processes, which reduces nitrous oxide emissions but increases methane emissions. Some technical solutions focus on modifying the animal feed to reduce the nitrogen in the manure, thereby reducing nitrous oxide emissions.
Energy, Industry, Waste, and Other
All non-agricultural categories together have much lower emissions than agricultural emissions alone.
N2O emissions related to energy are almost all from the combustion of fossil fuels. For example, the combustion of fossil fuels in power plants, cars, and airplanes not only causes CO2 emissions but also emits nitrous oxide (N2O). Any advances to reducing fossil fuel dependency will thus also reduce nitrous oxide emissions.
Most industry-related emissions are from the chemical industry for producing fertilizer, nylon, and similar products. Technologies are available to reduce emissions in these processes.
Nitrous oxide emissions from waste come from, for example, wastewater treatment and landfills.
Wikipedia: Nitrous oxideIPCC: AR6, 5.16 Anthropogenic nitrous oxide (N2O) emissions
Units and Measures
N2O emissions are expressed in the total weight in megatonnes per year. 1 Megatonne is equal to 1 million tonnes.
Wikipedia: MegatonneWikipedia: Global warming potential
About the Data
The last available year in all the emission datasets is 2023. N2O emissions come from the PRIMAP-Hist dataset. It is a rich dataset that combines several published sources to create a historical emissions time series for various greenhouse gases.
The Key Insights paragraph was created using a large language model (LLM) in combination with our data, historic events, and a structured approach for best accuracy by separating the context generation from the interpretation and narrative.
Data Sources
PRIMAP-hist The PRIMAP-hist national historical emissions time series (1750-2023)
Update cycle: Every few monthsDelay: Less than 1 yearCredits: Gütschow, Johannes; Busch, Daniel; Pflüger, Mika (2024): The PRIMAP-hist national historical emissions time series (1750-2023) v2.6. Zenodo.