Australia's Sources of CH4 Emissions
Key Insights
Methane’s Role In Australia
Methane contributes roughly 30% of Australia's total warming impact. Livestock has consistently been the dominant source, accounting for around 60% of methane emissions, followed by fugitive emissions at about 20%, crop production near 15%, and waste just under 10%. Fuel combustion and other sources are minor in comparison.
Livestock Dominance And Long Decline
Livestock emissions rose steadily through the post‑war era, peaking at around 90-100 megatonnes in the early 1970s. Since then they have eased gradually, settling around 60 today. Despite this long, slow decline, livestock remains the largest contributor and sets the overall level of methane emissions.
Fugitive And Crop Shifts
Fugitive emissions increased through the late 20th century and surged from the mid‑1990s to the late 2010s, peaking near 60 before falling back to around 40 since the late 2010s. Crop production tells the opposite story: after a long build‑up that reached roughly 60 around the early 2000s, emissions have declined sharply to about 15. Waste grew to around 20 by the late 1980s and has trended down to roughly 10. Fuel combustion has been low and gradually falling for decades.
Where To Focus Next
Today, the major sources are shifting downward: livestock is declining slowly, fugitive emissions are falling more recently, and crop production and waste are both trending lower. Sustaining the recent drop in fugitive emissions and accelerating the gradual decline in livestock are pivotal, while maintaining progress in crop production and waste can deliver further, near‑term climate benefits.
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, the effect lasts only for a relatively brief period (9 years on average), compared to hundreds of years for CO2. A reduction in emissions can cause a rapid decline in its atmospheric levels and climate impact.
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
About the Data
The last available year in all the emission datasets is 2023. Methane 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.