Sources of Methane Emissions

Methane emissions, a potent greenhouse gas, stem from a variety of natural and anthropogenic sources, contributing significantly to global warming. Natural sources include wetlands, oceans, and geological seepage, while human activities such as agriculture, fossil fuel extraction, waste management, and biomass burning also release substantial amounts of methane into the atmosphere. Understanding the diverse origins of methane emissions is crucial for developing effective strategies to mitigate its impact on climate change and safeguarding the health of our planet.

Tags: GS Paper – 3, Important International Institutions– Conservation— Environmental Pollution & Degradation

For Prelims: Food and Agriculture Organization (FAO), Methane Emissions, Related Initiatives

For Mains: Initiatives in the world and India to tackle methane emissions, Significance of methane as a greenhouse gas and its impact on climate change.

Table of Contents

Context:

Recently Studies conducted at the Institute for Global Change in Japan have unveiled multiple facets of methane emissions and their consequential impact on global warming.
Methane (CH4) contributes to 15–35% of the overall increase in human-induced greenhouse gas emissions.
Between 2020 and 2024, methane emissions saw an increase from 15 parts per billion (ppb) to approximately 21 ppb.

Details findings in the research:

Between 2019 and 2020, researchers at the Institute for Global Change in Japan meticulously analysed the atmospheric methane levels and their temporal variations.
They observed a consistent rise in methane concentration until the 1990s, followed by a period of stabilisation, and subsequently, a renewed upward trend starting around 2007.
Recent estimations indicate that today’s atmospheric methane concentration is threefold higher than it was 300 years ago.
Their models suggested a decline in methane emissions from fossil fuels from the 1990s to the early 2000s, with subsequent stability.
Moreover, their findings challenged the prevalent notion by highlighting that microbial activities are the predominant contributors to atmospheric methane, rather than fossil fuel combustion.
Increase in cattle-rearing in Latin America and more emissions from waste in South and Southeast Asia, Latin America, and Africa.

The sources of methane:

Scientists are increasingly recognising various sources of methane, most of which fit in two categories: biogenic and thermogenic.

Biogenic Sources:

Biogenic Methane originates from microbial activities, primarily driven by archaea called methanogens.These microorganisms thrive in oxygen-deprived environments,contributing to methane production through anaerobic decomposition processes. Here are some sources:
Animal Digestive Tracts: Livestock, such as cattle, produce methane during enteric fermentation in their digestive systems. According to studies, enteric fermentation in livestock accounts for approximately 14.5% of global anthropogenic methane emissions.
Wetlands: Wetlands are natural sources of methane due to the anaerobic decomposition of organic matter in waterlogged conditions. Wetlands cover about 6% of the Earth’s surface but contribute to around 20-25% of global methane emissions.
Rice Paddies: Methane emissions from flooded rice paddies result from anaerobic soil conditions, where methanogens thrive. Rice cultivation contributes to approximately 10% of anthropogenic methane emissions globally.
Landfills: Organic waste decomposition in landfills under anaerobic conditions generates significant methane emissions. Landfills contribute to about 11% of anthropogenic methane emissions.
Bodies of Water: Methane production 9% occurs in sediments of lakes, rivers, and oceans, primarily driven by microbial processes. Freshwater bodies and coastal ecosystems collectively contribute to methane emissions, although estimates vary.

Thermogenic Sources:

Thermogenic methane is formed through geological processes involving high temperatures and pressures deep within the earth’s crust. It is released during the extraction and processing of fossil fuels. These are include:
Natural Gas Extraction: According to the International Energy Agency (IEA), the oil and gas sector is responsible for approximately 30% of total anthropogenic methane emissions globally. This includes both intentional venting and unintentional leaks during extraction, processing, and transportation of natural gas.
Oil Production: The EPA estimates that methane emissions from oil production contribute to approximately 9% of total methane emissions. These emissions occur during various stages of oil production, including drilling, Leakage from equipment and infrastructure well completion, and storage.
Coal Mining: The Intergovernmental Panel on Climate Change (IPCC) estimates that coal mining activities account for approximately 8% of global anthropogenic methane emissions. These emissions result from both active mining operations and post-mining activities such as coal seam degasification.

How to track:

Both biogenic and thermogenic activities produce different isotopes of methane. Tracking the isotopes is a way to track which sources are the most active.
If there are fewer carbon-13 atoms than a certain level in a group of 1,000 methane molecules, the methane is from a biological source. If the methane is from thermogenic sources, such as trapped fossil fuels or geological activities, there will be more carbon 13 atoms in 1,000 molecules.

Initiatives to Tackle Methane Emissions:

A: By India:

‘Harit Dhara’ (HD): The Indian Council of Agricultural Research (ICAR) has developed an anti-methanogenic feed supplement called ‘Harit Dhara’ (HD). This supplement can reduce cattle methane emissions by 17-20% while potentially increasing milk production.
India Greenhouse Gas Program: Led by WRI India, the Confederation of Indian Industry (CII), and The Energy and Resources Institute (TERI), the India GHG Program is an industry-led voluntary framework aimed at measuring and managing greenhouse gas emissions.
National Action Plan on Climate Change (NAPCC): Launched in 2008, NAPCC aims to raise awareness among various stakeholders about the threat of climate change and steps to mitigate it. It engages representatives from the public, government agencies, scientists, industries, and communities.
Bharat Stage-VI Norms: India transitioned from Bharat Stage-IV (BS-IV) to Bharat Stage-VI (BS-VI) emission norms, reflecting a commitment to reducing vehicular emissions.

B. Global:

Methane Alert and Response System (MARS): MARS integrates data from a multitude of current and future satellites capable of detecting methane emission events globally. It notifies relevant stakeholders promptly, enabling swift action.
Global Methane Pledge: At the Glasgow climate conference (UNFCCC COP 26) in 2021, nearly 100 countries voluntarily pledged to reduce methane emissions by at least 30% by 2030 compared to 2020 levels, known as the Global Methane Pledge.
Global Methane Initiative (GMI): The GMI is an international public-private partnership focused on overcoming obstacles to the recovery and utilisation of methane as a clean energy source.

UPSC Civil Services Examination, Previous Year Questions (PYQs)

Prelims

Q1. Which of the following statements is/are correct about the deposits of ‘methane hydrate’? (2019)

Global warming might trigger the release of methane gas from these deposits.
Large deposits of ‘methane hydrate’ are found in Arctic Tundra and under the sea floor.
Methane in the atmosphere oxidised to carbon dioxide after a decade or two.

Select the correct answer using the code given below.

(a) 1 and 2 only
(b) 2 and 3 only
(c) 1 and 3 only
(d) 1, 2 and 3

Ans: (d)

Q2. Consider the following: (2019)

Carbon monoxide
Methane
Ozone
Sulphur dioxide

Which of the above are released into the atmosphere due to the burning of crop/biomass residue?

(a) 1 and 2 only
(b) 2, 3 and 4 only
(c) 1 and 4 only
(d) 1, 2, 3 and 4

Ans: (d)

Source:https://epaper.thehindu.com/ccidist-ws/th/th_international/issues/81450/OPS/GF9CO8MKP.1.png?cropFromPage=true

FAQs

Q: What are the primary sources of methane emissions?

The primary sources of methane emissions include natural sources like wetlands and geological seepage, as well as human activities such as agriculture (especially livestock digestion and manure management), fossil fuel production and use, landfills, and wastewater treatment.

Q: How does agriculture contribute to methane emissions?

Agriculture contributes to methane emissions mainly through enteric fermentation in ruminant animals like cows, sheep, and goats. Microbes in their digestive systems produce methane as a byproduct of breaking down food. Additionally, methane emissions can arise from manure management practices such as storage and spreading.

Q: Why is the fossil fuel industry a significant source of methane emissions?

The fossil fuel industry, including extraction, processing, and distribution of oil, natural gas, and coal, is a significant source of methane emissions. Methane leaks occur throughout the production and distribution process, from wellheads and pipelines to storage facilities and processing plants. Additionally, methane can be released during the extraction of coal through processes like coal mining.

Q: How do landfills contribute to methane emissions?

Landfills are a significant source of methane emissions due to the decomposition of organic waste in anaerobic (low oxygen) conditions. As organic matter breaks down, methane is produced as a byproduct. If not captured and controlled, methane can escape into the atmosphere. However, some landfills have implemented methane capture systems to mitigate emissions.

Q: What role does wastewater treatment play in methane emissions?

Wastewater treatment plants can be sources of methane emissions due to the anaerobic decomposition of organic matter in sewage sludge. When sewage is treated in anaerobic digesters, methane is produced as a byproduct. While some treatment plants capture and use this methane for energy, others release it into the atmosphere. Upgrading treatment facilities and implementing methane capture technologies can help reduce these emissions.

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Sources of Methane Emissions – UPSC