Greenhouse Effect

Greenhouse effect

It is a phenomenon discovered by Joseph Fourier in 1824 in which Earth retains part of solar energy that passes through the atmosphere. This phenomenon allows the existence of life on the planet's surface. The average temperature of Earth with the greenhouse effect is of 14CÐ'o. Without the greenhouse effect it would be вЂ" 19CÐ'o.

The greenhouse effect is being accentuated on Earth by increasing evaporation of water and emission of certain gases, such as carbon dioxide, methane, nitrogen oxides, ozone and chlorofluorocarbons, generated principally by human economic activity.

How the Greenhouse effect works?

- The solar radiation passes through the planetÐ'Ò's atmosphere that contains the greenhouse gases.

- The solar radiation warms the surface of the earth and heat rises from the atmosphere.

- Some heat Is able to pass through the gases but some heat just canÐ'Ò't pass through and remains atmosphere, adding to the overall temperature.

Greenhouse gases

Greenhouse gases are the gases present in the atmosphere which reduce the loss of heat into space and therefore contribute to global temperatures through the greenhouse effect:

Carbon Dioxide (C02)

It makes the biggest contribution to global warming (about 64%). The C02 concentration in the atmosphere is now about 30% higher than 200 years ago. If it continues to increase at the same rate it could nearly double by the year 2035. Burning of oil, coal and natural gas and the clearing and burning of vegetation are the main causes of the increased levels of this gas.

Methane (CH4)

Methane makes the next biggest contribution to global warming - some 20% of the total. In New Zealand, however, it is our major greenhouse gas. The concentration of CH4 in the atmosphere has risen by about 145% in the last 200 years. The digestive processes of ruminant animals (e.g. cattle, sheep, goats, deer), rice cultivation, venting of natural gas and waste decomposition in landfills are some of the major sources of CH4 emissions

Nitrous Oxide (N20)

Burning vegetation, industrial emissions and the effects of agriculture on soil are the major sources of nitrous oxide. Nitrous oxide levels in the atmosphere are estimated to have increased by 15% in the last two hundred years mainly due to more intensive agricultural practices.

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