Global Warming - An introduction to Green House Gases

The earth has naturally occurring greenhouse gases, including water vapour, which have protected the planet throughout its life. And greenhouse gases like carbon dioxide, methane, and nitrous oxide are all naturally occurring in the atmosphere, too. But, human activity has added more of these gases into the environment than it can handle, making the atmosphere too clogged up for some of the radiation to escape back into space. The build-up of gases is what contributes to the greenhouse effect of rising temperatures.

Carbon dioxide:

Carbon dioxide is the biggest pollutant, primarily formed when we burn fossil fuels for energy, such as when we drive fossil fuels propelled cars. Carbon dioxide makes up the largest percentage of greenhouse gases. Some carbon dioxide comes from other natural sources, for example, when animals (and humans) breathe or when living things die and decay. But the majority of carbon dioxide in the atmosphere comes from other human activities.

About one third of the carbon dioxide in the atmosphere comes from our sources of transportation - cars, buses, trucks, airplanes etc. A little less than one fourth of the carbon dioxide comes from lighting and heating our homes. The rest comes from factories and businesses.


Methane is the next most common greenhouse gas. Cattle are a big natural source of methane when they break down their food (and “break wind!”). With about one and a half billion cows in the world, that’s a lot of methane! The biggest source of methane comes from landfills, where waste breaks down and releases the gas. It’s also released during coal mining and the making of petroleum based products.

Nitrous oxide:

Nitrous oxide is another greenhouse gas. It’s produced naturally by bacteria in the soil. The human contribution to nitrous oxide comes from the use of nitrogen-based fertilizers. Although it’s not present in such large quantities as carbon dioxide or methane, the chemical make-up of nitrous oxide makes it actually trap more energy in the atmosphere than carbon dioxide—almost 300 times more—so it’s small, but powerful.