What are Greenhouse Gases?

What are Greenhouse gases?

Greenhouse gases trap heat in the atmosphere. These are the gases causing greenhouse effect. Carbon dioxide (CO2) is the main greenhouse gas emitted through human activities.

These gases absorb and emit radiant energy in the thermal infrared range thus leading to the greenhouse effect. The main greenhouse gases in the atmosphere of Earth are carbon dioxide, water vapour, methane, nitrous oxide and ozone.

The average temperature of the surface of Earth in the absence of greenhouse gases would be -18°C as opposed to the average temperature of 15 °C we see today. Apart from Earth, other planets such as Mars, and Venus also are said to contain greenhouse gases.

Table of Content:

• Greenhouse Gases
• List of Greenhouse Gases
• Greenhouse Gases Sources
• Global Warming
• Frequently Asked Questions

Greenhouse Gases – Which gases are greenhouse gases?

Greenhouse gases (GHGs) trap the infrared radiation coming from the Sun and prevent it from escaping to outer space. They reradiate it back to Earth’s atmosphere. They are responsible for increasing the temperature of the atmosphere.

Carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), Ozone (O₃), and chlorofluorocarbons (CFCs), along with water vapour are known as greenhouse gases.

Due to human intervention, the amount of greenhouse gases in the atmosphere has increased remarkably causing the greenhouse effect.

List of Greenhouse Gases – Greenhouse gases in atmosphere

The energy coming from the sun is either reflected, transmitted or trapped by Earth’s atmosphere. Greenhouse gases trap energy at longer wavelengths, i.e. infrared regions and increase the temperature.

Greenhouse gases, though present in a trace amount in the atmosphere, cause a considerable greenhouse effect.

What are the main greenhouse gases?

Major greenhouse gases are:

• Carbon dioxide
• Water Vapour
• Methane
• Ozone
• Nitrous oxide
• Chlorofluorocarbons

Greenhouse Gases Sources

As greenhouse gases are essential for the existence of life, they are present in the atmosphere in a trace amount.

• Natural sources of GHGs are volcanos, respiration by living organisms, decay and combustion of organic matter, etc.
• The amounts of GHGs are balanced in the atmosphere naturally by many physical, chemical or biochemical processes such as natural sinks that take-up CO₂, e.g. terrestrial vegetation
• Due to the industrial revolution and human intervention, the amount of greenhouse gases present in the atmosphere has drastically increased
• The main source of increased carbon dioxide in the atmosphere is the burning of fossil fuels, coal, petroleum and natural gas
• Urbanisation, deforestation and soil erosion has also contributed to the increased amount of carbon dioxide
• Various industries, solid and wastewater management are a source of increased methane. Rice cultivation has contributed considerably to increased greenhouse gases

Also see:

Global Warming

The greenhouse effect is essential for the sustainability of life on earth. Had it not been for greenhouse gases, the average temperature of the earth would have been -18℃ in comparison to normal levels, which is 15℃. Although the greenhouse effect is important for the existence of life, it has many repercussions.

A steady increase in the concentration of greenhouse gases has led to global warming. If it is left unchecked, it can increase the average temperature by 5℃ by the end of the century.

Global warming can cause many damaging effects on our environment and ecosystem and can lead to various climatic changes.

• Melting of polar ice caps can lead to a significant rise in the sea level. It can lead to submerging of low lying coastal areas and islands
• Oceanic temperature is rising and there is also a significant change in precipitation
• When the temperature is warmer, there is greater evaporation. It leads to the accumulation of more water vapour in the lower atmosphere, which absorbs infrared radiation and emits it back to the surface
• Global warming may lead to more unpredictable atmospheric changes. Extreme weather, drought, storms, wildfires, El Nino, etc. may become more frequent
• It may lead to loss of biodiversity, extinction of species, expansion of deserts and loss of various ecosystems, e.g. marshes and swamps, etc.
• It can lead to irreversible and irreparable changes leading to the extinction of life

Although we are in a critical situation, we can still reduce global warming and maintain a stable equilibrium by our conscious efforts and save the planet.

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