Greenhouse Gases

The atmosphere is made up of gases. Nitrogen alone makes up about 78% of the gases. Oxygen, which allows humans, plants and animals to respire makes about 21%. The other 1% is made up of Argon and Carbon Dioxide, with lots of other gases in very tiny quantities. Some of these smaller components, such as water vapor, carbon dioxide, methane and nitrous oxide, exhibit some greenhouse properties.

It is staggering to know that increasing amounts of these greenhouse gases, even though they form very small amounts in the atmosphere can be the subject of a huge phenomenon such as global warming. Let’s find out some more about these greenhouse gases and where they come from.

Water vapor

70% of the earth is covered by water. As the sun’s energy reaches the earth, it warms up surface waters and converts surface moisture into vapor. Water vapor is a gas and is the most abundant greenhouse gas. As the amounts of water vapor increase in the atmosphere, it condenses and falls back to the earth’s surface in the form of precipitation.

Carbon dioxide (CO2)

Carbon dioxide, another important greenhouse gas, exists naturally in the atmosphere. Humans and animals exhale carbon dioxide as a by-product of respiration. Green plants also absorb the carbon dioxide and use it to produce energy for themselves, releasing oxygen back into the atmosphere. This natural balance and regulation of carbon dioxide is part of a cycle known as the carbon cycle. But the slight distortion we are experiencing is because human activities such as industrialization, deforestation and the use of fossil fuels result in the expulsion of more CO2 into the atmosphere.


Methane molecules are known to have very powerful greenhouse effects, even though they exist in relatively smaller quantities than other greenhouse gases. Methane also exists naturally in nature, and also produced by human action. The gas is expelled into the atmosphere by decaying organic matter, decomposition of waste matter in landfills, livestock (and ruminant) digestion among others.

Nitrous oxide

This gas is released by the work of fossil fuel combustion, biomass burning and fertilizer action in soils. It is a significant greenhouse gas.

Chlorofluorocarbons (CFCs)

Industries that manufacture things like insulating foams, solvents, soaps, cooling things like Air Conditioners, Refrigerators and ‘Take-Away’ containers use something called chlorofluorocarbons (CFCs). These have greenhouse properties too and are known to have very destructive properties to the ozone layer. In recent time, international regulation has been strict on the use of CFCs.