Methane (CH4) is the simplest saturated hydrocarbon. It is a primary component of natural gas and is found in small amounts in the atmosphere.
Methane is an odorless, colorless, and flammable gas. It is commonly used as fuel.
Coal mining, wastewater, biomass, and landfills are responsible for global anthropogenic methane emissions.
Although Benjamin Franklin supposedly reported methane in 1774, Alessandro Volta (1777) is often credited with the chemical identification of methane after extracting gas by agitating the sediments at Italy’s Lake Maggiore. Methane can be used for making other organic chemicals.
In this article, we will understand the greenhouse effect and study methane as a greenhouse gas.
So, is methane a greenhouse gas? Yes, methane is a greenhouse gas as it can absorb heat and radiate it further. The presence of methane is essential for maintaining the earth’s temperature and climate as it is a chemically stable compound that can persist in the atmosphere for a long time. It slows down the escape of heat into space.
Let us readout the article till last for more information about how methane acts as a greenhouse gas and its impact on the environment.
What is Greenhouse Effect?
All the energy coming from the sun to earth does not go back into space. Only 30% of total energy gets reflected. 70 % reaches the earth’s surface, gets absorbed by land, oceans, and atmosphere, and raises the earth’s temperature.
The heat is radiated back into the space in the form of invisible IR light. 90% of this heat is trapped by atmospheric gases and does not reach space.
These atmospheric gases absorb the heat and release it back onto the earth’s surface. This process increases the temperature of the earth’s surface and is called the greenhouse effect.
The average temperature of the earth can decrease to -18°C.
The greenhouse effect is a natural phenomenon. It is the gradual warming up of the earth’s surface and troposphere.
The gases that trap heat in the atmosphere are called greenhouse gases. These gases act like a blanket around the earth, preventing the escape of all the heat in the form of infrared light.
This is similar to what happens in a greenhouse. A greenhouse is a building made of glass and used to grow some plants.
Sunlight enters the greenhouse through the glass but cannot escape back. Due to this, the temperature is high inside the building, even in winters. We can say that glass traps the sunlight.
Why is Methane (CH4) a Greenhouse Gas?
Methane is a hydrocarbon, and it is chemically stable. The atoms of methane are held loosely together, and they vibrate when the molecule absorbs heat.
The heat is then released by the vibrating molecules and absorbed by another atmospheric gas or goes back to the earth’s surface or goes into space.
Due to this process, the heat does not escape from the atmosphere quickly, and the temperature increases.
Methane stays in the atmosphere for around 12 years. The primary methane sink is its reaction with OH radicals in the troposphere to release water and carbon dioxide.
The global warming potential of methane is 25 times the effect of carbon dioxide. All the greenhouse gases act as insulation for the earth’s surface.
Nitrogen-related gases also cause the greenhouse effect. Read out the article is N2 a greenhouse gas.
What is Methane (CH4) made up of?
Methane is a covalent compound composed of carbon and hydrogen atoms.
The electronegativity of carbon and hydrogen are 2.55 and 2.2, respectively. The difference between electronegativities for a C-H bond is 0.35. Hence the bonds are polar.
The tetrahedral geometry of methane results in the orientation of C-H bonds such that dipole moments of bonds cancel each other. It is a non-polar molecule.
The central atom, C, in methane is sp3 hybridized. The s orbitals of hydrogen overlap with sp3 hybrid orbitals of carbon.
The molar mass of methane is 16 g/mole.
How does Methane affect Global Warming?
The greenhouse effect is an essential process for maintaining the temperature and climate of the earth, but it is often considered to be harmful. This is because greenhouse gases in the atmosphere exceed the optimum amount.
Since the industrial revolution, human activities are continuously contributing to the increase in the concentration of greenhouse gases in the atmosphere.
When more atmospheric gases are present, more heat-trapping will occur. This results in a greater extent of the greenhouse effect, and the temperature of the earth increases.
This gradual increase in temperature and change in the earth’s climate occurs due to greenhouse gases and leads to global warming. Some of the consequences of global warming are-
- Extreme weather conditions.
- It makes wet regions wetter and dry regions drier.
- Rise in sea level due to melting of the glacier.
- Change in the ecosystem, habitat, migration pattern, etc., for various land and marine animals.
The effect of a particular greenhouse on global warming depends on
- The abundance of gas in the atmosphere
- Duration for which the gas stays in the atmosphere
- GWP (global warming potential) indicates the duration for which the gas remains in the atmosphere and the gas’s strength to absorb energy.
A gas with a higher GWP absorbs more heat and increases the temperature to a greater extent.
Global warming potential is measured by averaging over 100 years. The value of GWP for methane lies between 28 and 36, while for carbon dioxide GWP is 1.
Water vapor is the most abundant greenhouse gas, but the duration for which it stays in the atmosphere is low, due to which it does not have a significant effect.
Since 1880, the combined land and ocean temperature increase is 0.13° F per decade on average.
The rate of increase has changed to 0.32° F per decade from 1981.
Sources of Methane (CH4) Emission
There has been an increase in the global temperature due to an increase in the concentration of greenhouse gases.
To solve this problem, we need to be aware of various sources of methane. The majority of methane is released in the environment due to human activities.
The major sources are-
• Cattle, sheep, goats, etc., produce methane due to their digestion process. Cow dung is also used as a fuel as it contains methane. Therefore, methane is an important constituent of biofuel.
• Storage of animal manure results in methane production.
Energy and Industry
• Methane is produced and released in the atmosphere during the production, processing, transmission, and storage of natural gas. Methane is an important constituent of natural gas.
• Coal mining and burning of fossil fuel
• During the production, processing, storage, and transmission of crude oil, methane gas might leak.
• In landfills, the waste decomposes, and wastewater is treated, resulting in the release of methane.
• Methane content is less from drier landfills.
• Natural wetlands have bacteria that decompose organic matter in the absence of oxygen and release methane gas.
• Microbes produce methane in the gut of termites,
• In the ocean, anaerobic digestion by zooplankton and fish releases methane gas.
• It is produced in sediments and drainage areas of coastal regions.
• When methane molecules are frozen into ice crystals, methane can escape from these crystals into the atmosphere.
According to United Nations, maximum anthropogenic emission of methane is due to fossil fuel, waste, and agriculture
How to Reduce Methane Emissions?
Methane is significant for our survival, but excess methane emission is a global problem. To control this, action needs to be taken at the local and international levels.
We cannot control methane emissions from natural sources. To begin with, we can understand the anthropogenic sources of emission and reduce the emission due to human activities.
• Technology should be upgraded regularly in industries to minimize methane leaks into the atmosphere.
• Management practices should be enhanced following modern technologies.
• In coal mines, the methane released can be used to produce heat and electricity there and then only.
• We should use clean and renewable sources of energy instead of fossil fuel as pollution due to fossil fuel releases methane gas.
• In the agriculture sector, the burning of fields should be avoided after harvest. The livestock food must be modified such that less methane is released on the digestion of food.
• Composting organic waste instead of sending it to landfills reduces methane emission and provides many environmental and economic benefits.
Comparison of Carbon Dioxide and Methane as Greenhouse Gas
Carbon dioxide forms the major part of greenhouse gas emissions, while methane emissions are relatively less.
Carbon dioxide can persist in the atmosphere for centuries.
Carbon dioxide is more abundant and stays for a more extended period of time; still, methane is considered a much more potent greenhouse gas.
Methane emissions are much easier to tackle than carbon dioxide emissions and can be controlled.
Apart from CO2, CFC gas is also one of the hazardous gas causing the greenhouse effect.
I have written a specific article on the is a CFC greenhouse gas.
Methane is the simplest saturated hydrocarbon.
It is a greenhouse gas.
It can trap heat and increase the temperature of the earth’s surface.
Greenhouse gases act as an insulating blanket around the earth.
The greenhouse effect is vital for our survival but becomes harmful when greenhouse gas concentration increases in the atmosphere.
This excess concentration of greenhouse gases results in global warming.
The greenhouse gas concentration has reached new heights and needs to be controlled.
We must act together to reduce methane emissions into the atmosphere.
Related Topic: Why is the Ozone layer important