Unexpected Sources of Methane: Rethinking Our Role in Greenhouse Gas Emissions

Discover the hidden contributors to methane emissions and explore what they mean for our fight against climate change.

By Medha deb

Created on Sep 27, 2025

Discover the hidden contributors to methane emissions and explore what they mean for our fight against climate change.

Methane is a potent greenhouse gas, second only to carbon dioxide in its overall impact on climate change. But while CO₂ often steals the spotlight, methane’s warming potential is surprisingly high: over a 20-year period, its heat-trapping effect is more than 80 times that of CO₂. Understanding where methane comes from—and what unexpected sources might be contributing to its rise—is critically important if we want to mitigate global warming.

This article examines not only the clear contributors like livestock and fossil fuels, but also the lesser-known emitters that complicate our efforts to cut emissions. Anticipate surprises: from everyday foods to household routines and even the trees we thought only helped the climate.

What Is Methane and Why Is It a Problem?

Methane (CH₄) is a simple hydrocarbon gas. Although it constitutes a much smaller portion of total greenhouse gas emissions than carbon dioxide, it is far more efficient at trapping heat in the atmosphere. It’s estimated that methane is responsible for about 30% of the current warming since pre-industrial times.¹ Importantly, methane has a comparatively short atmospheric lifetime—about a decade—but its intense warming effect during that time means addressing methane leaks and sources could bring rapid climate benefits.

Natural sources: wetlands, termites, oceans, and wildfires
Anthropogenic (human-caused) sources: agriculture (especially livestock), landfills, fossil fuel extraction, rice paddies, waste treatment, and certain household products

The Big Emitters: Wetlands, Agriculture, and Fossil Fuels

While this article focuses on the lesser-known sources, it’s crucial to contextualize methane emission data by recognizing the largest contributors.

Wetlands: By far the largest natural source of methane, wetlands emit methane through the decomposition of organic matter by microorganisms in oxygen-poor conditions.
Fossil fuel industry: Oil, coal, and natural gas operations leak significant methane during extraction, processing, and delivery.
Agriculture: Particularly ruminant livestock (cows, sheep), which produce methane via enteric fermentation; manure management and rice cultivation are also major contributors.
Waste: Landfills generate methane as organic waste decomposes anaerobically (without oxygen).

Surprising Everyday Sources of Methane

Beyond the big emitters, a variety of unexpected sources contribute methane. Discovering these can reveal overlooked opportunities for climate action—and change our perspective on everyday life.

1. Household Food Waste

Throwing away food does more than waste resources—it contributes substantially to methane emissions when food decomposes anaerobically in landfills. When we toss food scraps rather than composting or digesting them, this organic matter generates methane as it decays without air.

EPA estimates suggest 24% of landfill-derived methane in the US comes from food waste alone.
Every banana peel or uneaten meal sent to the trash may play a part in driving up atmospheric methane.

2. Rice Production

While rice is a staple for billions, rice paddies are among the world’s most significant agricultural methane sources. Flooded conditions in paddies create oxygen-poor environments where methane-producing microbes thrive.

Rice cultivation is estimated to account for 10% of global methane emissions from human activities.
New farming methods (e.g., alternate wetting and drying) could help reduce emissions.

3. Cow Burps (Enteric Fermentation)

You may have heard livestock are methane emitters, but the details are surprising. Ruminants like cows and sheep emit methane primarily through burping, not flatulence. Their unique stomachs, which ferment food using bacteria, enable them to digest tough plant matter but produce methane as a byproduct, which is released mostly from their mouths.

Enteric fermentation accounts for about 40% of agricultural methane emissions globally.
Diet changes, such as adding seaweed supplements, show promise in reducing these emissions.

4. Compost and Manure

Composting is widely encouraged for reducing waste, but poorly managed piles—those lacking sufficient aeration—can become anaerobic and produce methane. Similarly, large piles of manure left untreated on farms often generate considerable methane emissions.

Proper aeration and turning of compost piles significantly curtail methane production.
Covering manure lagoons with plastic or employing methane-capture technology (biogas) can also help.

5. Biomass Burning

Unlike CO₂, which is the main byproduct of complete combustion, incomplete burning of wood, grass, crop residue, or yard waste can release methane in addition to particulate matter and other pollutants.

Wildfires, prescribed burns, and backyard burning all contribute to methane emissions.
Encouraging better waste management and reducing unnecessary burning can make a difference.

6. The Curious Case of Trees

It may seem counterintuitive, but some trees can be sources of methane. Recent research has revealed that trees—especially in wetlands but sometimes even in upland environments—can emit methane through various mechanisms.

Wetland trees act as ‘chimneys,’ transporting methane from waterlogged soils up their trunks and into the atmosphere.¹
Some trees produce methane internally, possibly through microbial action or photochemical reactions in their foliage or bark.¹
Estimates suggest tropical wetland trees may emit up to 65 million metric tons of methane annually—about a third of all wetland contributions.¹

Importantly, other research now indicates non-wetland trees may also act as methane sinks, especially in temperate and upland forests. The trunks and woody tissues sometimes absorb atmospheric methane, turning some trees into net methane removers.³ The overall balance is a subject of ongoing investigation and highlights the surprisingly dynamic role trees play in the global methane budget.¹

7. Household Gas Appliances

Even when off, kitchen stoves and other gas appliances can leak small but measurable amounts of methane over time. These seemingly ‘minor’ leaks add up due to the millions of gas stoves and heaters worldwide.

Leaks are often undetectable by smell but can be significant at the scale of urban infrastructure.
Regular maintenance and new sealing technology may help cut household methane leaks.

8. Rubbish Bins and Plastics

While plastics do not decompose rapidly, recent research shows that some plastics (notably low-density polyethylene) emit methane and ethylene when exposed to sunlight and environmental conditions.

These emissions stay extremely small per piece but add up globally due to the sheer mass of plastic in the environment.
Proper waste management and minimizing plastic pollution remain crucial.

9. Cultivated Peatlands and Bog Restoration

Drained peatlands, often turned into farmland, are sources of CO₂ due to organic matter oxidation. But wet restored peatlands typically re-generate methane; the challenge is to balance land restoration with greenhouse gas emissions, a nuanced calculus for climate policy.

Balancing Methane Sinks and Sources: The Complexity of Trees

Traditionally, forests have been considered climate ‘good guys’ because they absorb carbon dioxide as they grow. However, new research shows that their role with regard to methane is much more complex.

Trees can emit methane (especially in wetlands, or due to microbial activity in wood).
Trees can also absorb methane, particularly at higher trunk levels, due to methanotrophic microbes in bark and woody tissues.^3,4
Whether a particular forest acts as a net methane source or sink depends on species, local conditions, climate, and whether the soil is waterlogged or not.^1,3,4

Trees as Methane Sources and Sinks
Type	Source	Sink
Wetland Trees	Very high (proxy for wet soils)	Low
Upland/Temperate Trees	Low-medium (microbial/photochemical)	High (methane absorption by bark & wood microbes)
Dead Wood	Variable (mostly source due to decay)	Low/none

These discoveries are reshaping how scientists account for forests in global greenhouse gas inventories. Protecting forests for carbon storage may be even more valuable than previously thought, especially if tree-methane uptake proves widespread.³

Emerging Solutions and What Individuals Can Do

Compost food scraps, or participate in municipal digestion programs, to avoid landfill methane.
Reduce red meat and dairy consumption to limit enteric fermentation emissions from livestock.
Advocate for methane-capture at landfills and manure lagoons; support local strategies that encourage methane mitigation in agriculture.
Support research and restoration that maximize forests’ net sink behavior for methane.
Dispose of plastics responsibly and participate in recycling to help limit related emissions.
Maintain home gas appliances to avoid leaks—or consider electrifying as infrastructure allows.

Frequently Asked Questions (FAQs)

Q: Why is methane more potent than carbon dioxide?

A: Methane’s molecular structure enables it to absorb heat very efficiently, making it over 25 times more potent than CO₂ at trapping heat over 100 years—and over 80 times more potent over 20 years.

Q: Can forests absorb as much methane as they emit?

A: Some forest ecosystems, particularly upland and temperate ones, have been shown to absorb more methane than they emit due to the activity of methane-eating microbes in tree bark and wood. Wetland forests, however, are usually net emitters.^1,3,4

Q: Is composting always better for methane reduction?

A: Composting is usually better if done properly (with enough oxygen present). Poorly managed piles can become anaerobic and produce methane, but well-aerated composting mostly generates carbon dioxide and far less methane.

Q: How can I reduce methane emissions in everyday life?

A: Steps include composting organics, choosing renewable energy, supporting methane-reducing agricultural innovations, reducing meat consumption, and maintaining or replacing aging gas appliances.

Q: What is the role of plastic in methane emissions?

A: Sunlight-exposed plastic waste, particularly in landfills or the environment, can emit small amounts of methane and other hydrocarbons—a new and growing concern alongside other plastic pollution effects.

Key Takeaways

Methane is a powerful greenhouse gas with diverse, sometimes surprising, sources.
Understanding methane sinks and sources—especially the new science suggesting trees can absorb as well as emit methane—will refine policy and solutions.
Small, habitual changes in food, waste, and household energy use, when multiplied across billions, can make a meaningful difference.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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