Cambodia's Sources of CH4 Emissions
Key Insights
2024 CH4 Emissions Profile
Cambodia's methane emissions totalled around 24.1 megatonnes CO2e in 2024. Crop emissions dominated, at around 15.6 megatonnes CO2e or 64.7% of the national total, rising by about 0.17 megatonnes CO2e per year over the ten years to 2024. Livestock contributed 5.4 megatonnes CO2e (22.3%) and declined slightly. Waste rose to 1.3 megatonnes CO2e (5.5%), while fugitive emissions and fuel combustion were broadly stable at around 1.1 and 0.7 megatonnes CO2e.
Historic Livestock Emissions
Livestock emissions rose gradually from around 1.5 megatonnes CO2e in 1851 to just over 3 megatonnes by the mid-1960s, then climbed sharply before falling to about 2.1 megatonnes in 1977. They recovered over the following decades, peaking at roughly 6.7 megatonnes CO2e in 2009, before easing to around 5.4 megatonnes CO2e in 2024.
Historic Fugitive Emissions
Fugitive emissions were negligible through most of the nineteenth and twentieth centuries, reaching only around 0.1 megatonnes CO2e by 1994. They then jumped sharply to roughly 0.9 megatonnes in 1995. Emissions remained close to 1 megatonne thereafter, peaking at around 1.1 megatonnes CO2e in 2015 and ending at about 1.1 megatonnes CO2e in 2024.
Historic Waste Emissions
Waste emissions began at around 0.3 megatonnes CO2e in 1851 and increased only slowly into the mid-twentieth century. They varied during the following decades, falling to around 0.3 megatonnes in the mid-1970s before recovering. Growth became more sustained from the late 1980s, rising from roughly 0.5 megatonnes to a peak of around 1.3 megatonnes CO2e in 2024.
Historic Crop Emissions
Crop emissions began at roughly 2.6 megatonnes CO2e in 1851 and rose to around 4.6 megatonnes by the mid-1930s. They climbed rapidly thereafter, but fluctuated and then fell to around 4.1 megatonnes in 1975. Emissions subsequently increased strongly, reaching a peak of roughly 16 megatonnes CO2e in 2021 before ending at around 15.6 megatonnes CO2e in 2024.
Historic Fuel Emissions
Fuel combustion emissions rose gradually from around 0.4 megatonnes CO2e in 1851 to roughly 0.7 megatonnes by the early 1920s. They declined through the mid-twentieth century, reaching about 0.4 megatonnes in the mid-1980s, then recovered. Emissions have remained near 0.7 megatonnes since the early 1990s, peaking at around 0.8 megatonnes CO2e in 2019 and ending at about 0.7 megatonnes CO2e in 2024.
Background
The chart shows a national breakdown by source of the yearly methane (CH4) emissions from human activities expressed as weight in megatonnes (Mt). In the scientific literature, these are referred to as anthropogenic emissions. Human-induced methane emissions increase atmospheric methane, which is warming the Earth. The sources of human methane emissions are
- Livestock
- Fugitive emissions from the fossil fuel industry
- Crop production
- Fossil fuel combustion
- Waste management
- Other processes
Methane's Global Warming Potential
Methane has a much higher Global Warming Potential (GWP) than CO2. However, Methane emissions in the atmosphere decay with an average lifetime of about 12 years so its long term warming-effect is much less compared to CO2 which stays on average for hundreds of years in the atmosphere. Meaning: Methane's short term warming effect is much higher, but long term warming effect is much lower. A reduction in emissions can cause a rapid decline in its atmospheric levels.
Livestock
Livestock emits methane that is produced in the animals' digestive system. Most methane is emitted from the mouth during rumination. A much smaller amount of methane is emitted from the manure. Depending on how the manure is managed, i.e., wet or dry, more methane is emitted. Wet management leads to higher methane emissions than dry management. However, dry management also emits nitrous oxide (N2O), which is another potent greenhouse gas.
Fugitive emissions from fossil fuel industry
Fugitive methane emissions are from the intentional and accidental release of methane, which happens during the extraction, storage, and transportation processes in the fossil fuel industry. Examples are methane leaks during oil and gas handling, storage, transport, incomplete combustion, and many more. Also, methane is deliberately ventilated from mines during the extraction of coal.
Methane is a primary part of “gas”, also called “natural gas” or “fossil gas”. Natural gas is used, for example, for heating and electricity generation, whereby it emits CO2 during the combustion process. However, when natural gas leaks (unburned) it contains a lot of fugitive methane emissions.
Waste
Waste from landfills and wastewater produces a lot of methane when biodegradable material breaks down without oxygen.
Crop production
Crop production emissions are largely from rice cultivation, which generates large amounts of methane during plant growth. These emissions are from flooded paddies, which create the swamp-like environment of rice fields. There are agricultural techniques to reduce emissions significantly, like periodic drainage and aeration. Rice is the main staple for about half the world's population, and its emissions are a significant part of total human methane emissions.
Fuel combustion
Fuel combustion emissions are mostly from the incomplete combustion of fossil fuels. As mentioned before, natural gas consists largely of methane, and when the combustion does not happen completely, methane enters the atmosphere.
Other
Other human-induced methane emissions include industrial processes and product uses.
Wikipedia: Anthropogenic Sources of Atmospheric MethaneIPCC: AR6, 5.2.2.2 Anthropogenic CH4 emissions
Units and Measures
CH4 emissions are expressed in the total weight in megatonnes per year. 1 Megatonne is equal to 1 million tonnes.
Wikipedia: MegatonneWikipedia: Global warming potential
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National methane emissions data through 2024 is from the PRIMAP-hist dataset, which combines several published sources into a historical emissions time series.
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 (1750-2024)
Update cycle: Every few monthsDelay: Less than 1 yearCredits: Gütschow, J.; Busch, D.; Pflüger, M. (2025): The PRIMAP-hist national historical emissions time series v2.7 (1750-2024). zenodo. doi:10.5281/zenodo.17090760