China, Hong Kong's Sources of N2O Emissions
Key Insights
Early Development and Industrialization
Hong Kong's journey of anthropogenic N2O emissions began modestly in the 19th century, with agriculture and waste being the primary contributors. The New Territories Lease in 1898 marked a period of urban development, which likely increased emissions due to construction activities. The post-war industrial boom in 1949 further accelerated emissions as Hong Kong transformed into a manufacturing hub, relying heavily on coal and oil for energy.
Economic Growth and Infrastructure Expansion
The opening of the Mass Transit Railway in 1972 and the Sino-British Joint Declaration in 1984 spurred economic growth and infrastructure development, contributing to rising emissions. The handover to China in 1997 marked a new era of economic integration, leading to increased trade and industrial activities. This period saw significant increases in emissions, particularly from the energy sector, as the region's energy demands grew.
Recent Trends and Temporary Reductions
In recent decades, emissions from energy have dominated, although there have been fluctuations. The global financial crisis in 2008 and the COVID-19 pandemic in 2020 led to temporary reductions in emissions due to economic slowdowns. However, these reductions were short-lived, with emissions rebounding as economic activities resumed. Despite these fluctuations, Hong Kong's emissions remain a critical concern, reflecting the region's ongoing economic activities and energy consumption patterns.
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 generated using a large language model (LLM) using a structured approach to improve the accuracy. This included 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.