Zimbabwe's Sources of CH4 Emissions
Key Insights
Colonial Impact on Emissions
The colonization of Zimbabwe by the British South Africa Company in 1890 marked the beginning of significant land-use changes, including deforestation and the introduction of European farming techniques. These activities likely contributed to an increase in methane emissions, particularly from livestock, as European agricultural practices were adopted. The establishment of Southern Rhodesia as a British colony in 1923 further accelerated industrial and agricultural activities, leading to increased emissions from land-use changes and infrastructure development.
Post-Independence Economic Growth
Following Zimbabwe's independence in 1980, the country experienced economic growth and industrialization, which contributed to a rise in greenhouse gas emissions. The expansion of agriculture, particularly tobacco and maize, likely increased emissions due to fertilizer use. The growth in industrial activities and energy production, primarily from coal, also contributed to higher emissions. This period of economic development resulted in a measurable increase in methane emissions, particularly from livestock and waste.
Recent Trends and Challenges
In recent decades, Zimbabwe has faced various challenges that have impacted its emissions profile. The severe drought in 1992 led to a temporary decrease in methane emissions from livestock, while the land reform program in 2000 caused significant changes in land use, affecting emissions from agriculture. More recently, the expansion of the Hwange Power Station in 2015 increased coal-fired electricity generation, contributing to higher emissions. Despite efforts to reduce reliance on fossil fuels, such as the introduction of ethanol production in 2010, emissions from coal and other sources remain significant challenges for Zimbabwe.
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 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.