China, Hong Kong's Sources of N2O Emissions
Key Insights
Current Source Mix
In China, Hong Kong Special Administrative Region, the largest share of N2O emissions today comes from other sources-about a third of the total. Waste and energy each contribute just under a third, while agriculture is under a tenth and industry is negligible. For the leading sectors, recent annual emissions sit around 0.1-0.2 megatonnes, shaping most of the territory's current warming impact.
Historical Shifts And Peaks
Energy-related emissions rose through the 1970s and surged around the late 1980s, peaking near 0.5 megatonnes in the early 1990s before trending downward to roughly 0.1. "Other" climbed steadily from the 1970s to the late 1990s-peaking around 0.4-then declined to about 0.1. Waste was relatively steady around 0.1 from the 1970s to the late 1990s, then increased since the turn of the century toward 0.2. Agriculture grew through the mid-20th century, eased from the 1980s, and has remained low and steady near 0.02-0.03.
What The Trends Suggest
Among major sources, energy and other are on a downward trajectory, while waste has been rising since around 2000 and now rivals the largest contributors. Agriculture is stable at low levels. Sustaining the declines in energy and other, while reversing the recent rise in waste, would have the greatest effect on bringing total N2O emissions down.
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.