Methane (CH4), a naturally occurring gas, is the main component of natural gas and a potent greenhouse gas (GHG). As a greenhouse gas, the question now is: how does methane affect Global Warming?
Upon escaping into the atmosphere, greenhouse gases act as a blanket insulating the Earth, absorbing energy and slowing the rate at which heat leaves the planet. In the case of methane, this energy is absorbed remarkably well.
This process, referred to as the greenhouse effect, occurs naturally, and without it, our planet’s average temperature would fall below freezing.
However, with the increase in greenhouse gas emissions over the last few centuries, the greenhouse effect has grown consistently stronger, contributing to the warming of our planet at a rate many consider alarming.
Table of Contents
What Is Methane?
Methane (CH4) is a hydrocarbon that is a primary component of natural gas. It is an odorless gas that lacks color and is highly flammable. Methane is found both in nature and as a byproduct of excessive human activity and serves as the most basic member of a series of hydrocarbons part of the paraffin series, better known as alkanes.
Methane is the second most abundant anthropogenic GHG after carbon dioxide (CO2), accounting for about 16 percent of global emissions. Methane is even lighter than air and can burn easily when dispersed into the atmosphere, as it is not heavily soluble in water.
While methane can be considered a stable alkane, it can be dangerously explosive considering the current properties of the surrounding air, which means methane can and has already accounted for several explosions in areas such as coal mines and collieries.
Methane, as a greenhouse gas (GHG), generates a presence in the atmosphere that affects the earth’s temperature and climate system. Methane is emitted from a variety of anthropogenic (human-influenced) and natural sources.
Over the last two centuries, methane concentrations in the atmosphere have doubled, largely due to human-related activities. Because methane is both a powerful greenhouse gas and short-lived compared to carbon dioxide, achieving significant reductions would have a rapid and significant effect on atmospheric warming potential.
Methane is generally a secondary byproduct of the industrial processes from which it is emitted. Coal mines, for example, seek to vent methane from the mine workings because it can cause explosions. Historically, mining companies have not viewed the associated methane as an energy resource in its own right.
How does Methane affect Global Warming?
Methane, while a natural gas found in the atmosphere, when mixed in conjunction with industrial activity, can become hazardous and detrimental to living organisms, especially humans.
Methane is a major contributor of greenhouse gas emitted into the atmosphere. Greenhouse gases, also known as GHGs, are the substances that provoke heat to be trapped in the Earth’s atmosphere and ultimately raise global surface temperatures.
It’s easiest to think of greenhouse gasses like blankets that are being used to warm the Earth. Sure, one blanket won’t cause too much harm – but imagine being swaddled in twenty blankets – you would start to feel a little too warm. That’s precisely how the Earth feels right now due to excessive greenhouse gas emissions, which provoke global warming.
As stated earlier methane is one of several gases which act as a sort of blanket between the Earth and the stratosphere. By trapping the energy from the sun’s rays, they retain heat and warm the atmosphere around them.
This not only elevates global temperatures but also contributes to climate change events such as the melting of the polar ice caps and the rising of sea levels, as well as more immediately noticeable symptoms such as more frequent and more intense extreme weather events.
Hence, methane is considered a greenhouse gas as it also contributes to the greenhouse effect and warming of the planet.
In addition, methane also reacts with various hydroxyl radicals, which serve as a form of “laundry detergent,” to clean out the rest of the pollutants present in the atmosphere. Methane ultimately destroys these hydroxyl radicals, leaving the atmosphere prone to even more ozone-depleting substances.
In this way, it is best to think of methane as a pesticide, as methane prevents cleaner air in a similar way to how these insects can prevent an otherwise fruitful harvest.
Methane is also a part of the creation of ground-level ozone, which is another gas that can harm human life even though these substances are never directly emitted into the atmosphere.
Ground-level ozone is produced when various chemicals and compounds are mixed, often as a direct result of the pollution caused by gasoline-powered vehicles or the activity from nuclear plants.
In combination with the sun, methane can provoke further ground-level ozone: which is detrimental to fragile ecosystems, forests, and crops given their nature to remain low in the air.
Many may view methane as trite, seeing as it is found in nature but natural gas has never been more of a threat.
In fact, according to a global methane assessment conducted by the United Nations Environment Program, there is now more than twice the amount of methane in the atmosphere than there was before the era of excessive industrial production, with a sharp spike in the amount of methane in the air following the 1980s.
What are the Top Three Sources of Methane Emissions?
Methane has a variety of different sources and uses in our world. However, a sharp increase in anthropogenic activity over the last two centuries has seen methane concentrations in our atmosphere surge at an alarming rate.
Modern methane monitoring methods have revealed that there are roughly two-and-a-half times the amount of methane in our environment today than there was before the Industrial Revolution.
This is especially concerning given methane’s status as a highly potent greenhouse gas. While carbon dioxide may hog the headlines when it comes to environmental issues, methane’s role in contributing to global warming and climate change should not be underestimated.
Methane levels have more than doubled over the last 150 years. This is because of human activities like fossil fuel use and intensive farming. Before the Industrial Revolution, natural sinks kept methane levels in a safe range.
A recent UN report suggested that the world is on track to warm more than 2°C, well above what countries had agreed on with the Paris Agreement. Extreme weather events like heatwaves and rainstorms are on the rise, bringing destruction across the world, with no country spared.
There are both natural and human sources of methane emissions. The main natural sources include wetlands, termites, and the oceans. Natural sources create 36% of methane emissions. Human sources include landfills and agriculture.
But the most important source is the production, transportation, and use of fossil fuels. Human-related sources create the majority of methane emissions, accounting for 64% of the total.
The Global Methane Assessment (GMA) conducted by the joint effort of the United Nations Environment Programme and Climate and Clean Air Coalition revealed that anthropogenic methane accounts for 64% of the total methane emission, with 90% coming from three main sources: agriculture (40%), fossil fuel (35%), and landfill, solid waste, and Wastewater(20%).
- Agriculture
- Fossil Fuel Industry
- Landfill, Solid Waste and Wastewater
1. Agriculture
Agriculture is by far the biggest source of anthropogenic methane, with about 32% of total emissions originating from enteric fermentation and manure management, while the remaining 8% is attributed to rice cultivation.
Animal husbandry is a source of methane emissions from feed production and manure deposition, which is known as enteric fermentation in farm animals. This creates 27% of human methane emissions.
Animals like cows, sheep, and goats are examples of ruminant animals. During their normal digestion process, they create large amounts of methane. Enteric fermentation occurs because of the microorganisms in the stomachs of these animals.
Animal husbandry farming creates 90 million metric tons of methane per year. Rice farming is another large agricultural source of methane emissions. Paddy fields for rice production are man-made wetlands. They have a high moisture content, are oxygen-depleting, and have ample organic material.
This makes an excellent environment for the microbes that break down the organic matter to produce methane. Methane-consuming microorganisms absorb part of the methane produced.
However, the great majority is discharged into the atmosphere. An annual 31 million tonnes of methane are produced by rice agriculture. An annual 31 million tonnes of methane are produced by rice agriculture.
2. Fossil Fuel Industry
The largest human source is the production, distribution, and combustion of fossil fuels. This creates 33% of human methane emissions. Methane emissions are produced wherever there are fossil fuels. It gets released whenever fossil fuels are extracted from the earth.
Coal mining which includes active and abandoned mines, releases another 12% as part of the total fossil fuel-derived emissions. Within oil and gas extraction, gas venting and fugitive emissions are the main causes of methane emissions
Furthermore, a large portion of methane emissions are caused by natural gas. Methane is the main component of natural gas. So leakage throughout this industry releases methane straight into the atmosphere. This includes the extraction, processing, and transportation of natural gas.
Oil wells can also have methane deposits that get released during drilling and extraction. The refinement, transportation, and storage of oil are also sources of methane emissions.
By using fossil fuels, you contribute to the most important source of methane emissions. Fossil fuel production, distribution, and use create 110 million metric tons of methane per year.
3. Landfill, Solid Waste and Wastewater
As the third-largest methane emitter, the waste sector generally releases methane from landfills and waste. This accounts for 16% of human methane emissions.
Landfilling organic waste is known to generate landfill gas, which mainly contains methane gas from anaerobic bacteria. Methane is generated by the decomposition of solid waste in landfills. This also happens with animal and human waste streams.
Landfills and open garbage dumps are full of organic matter. The garbage contains things like food scraps, newspapers, cut grass, and leaves. Every time new garbage comes in it gets pilled over the old garbage that was already there.
The organic matter in our garbage gets trapped in conditions where there is no oxygen. This provides excellent conditions for methane-producing microbes. Therefore, creating an anoxic environment allows methane-generating bacteria to thrive.
These bacteria will break down the waste by consuming the organic matter in the waste, which produces large amounts of methane emissions. Even after a landfill is closed, bacteria will continue to decompose the buried waste. Which will emit methane for years.
Also, wastewater from domestic, municipal, and industrial sources can also produce methane emissions. Wastewater can be either released, stored, or sent for treatment to remove contaminants.
As with landfills, if the decay of organic material in wastewater happens without oxygen, then this will create methane. Landfills, solid waste, and wastewater produce 55 million tonnes of methane per year.
Why is Methane (CH4 ) worse than Carbon (iv) Oxide CO2
Methane is the second-most abundant greenhouse gas after carbon dioxide (CO2). However, methane plays a much greater role in warming the planet. Over a 100-year period, methane is 28 times more powerful than carbon dioxide at warming the earth.
Over 20 years, that comparison jumps to approximately 80 times. On the one hand, methane persists in our atmosphere for a far shorter time period than CO2 (an estimated 12 years compared to carbon’s centuries-long lifespan)
Additionally, as methane is emitted into the air, it reacts in several hazardous ways, primarily leaving the atmosphere through oxidation, thereby forming water vapor and carbon dioxide. So, not only does methane contribute to global warming directly but also indirectly through the release of carbon dioxide.
Furthermore, during the oxidization process, methane reacts with hydroxyl radicals (OH). These naturally occurring molecules act as a “detergent,” cleaning methane and many other pollutants from the air. Thus, methane reduces the number of hydroxyl radicals available to remove other types of air pollutants.
Methane also contributes to the formation of ozone, decreasing air quality and leading to various health issues in animals, premature human deaths, and reduced crop yields.
Conclusion
Limiting methane emissions is no magic bullet to halt global warming. Nonetheless, it would definitely buy us some time to decarbonize every other sector before the climate crisis becomes irreversible.
As has been identified over time, anthropogenic activities are major contributors to the emission of this greenhouse gas. Hence, there is a need for humans to address this environmental issue by resorting to more environmentally friendly production activities.
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Ahamefula Ascension is a Real Estate Consultant, Data Analyst, and Content writer. He is the founder of Hope Ablaze Foundation and a Graduate of Environmental Management in one of the prestigious colleges in the country. He is obsessed with Reading, Research and Writing.