Global Warming

GLOBAL WARMING IS a term that is used to refer to an increase in Earths average surface temperature. It is due mostly to the release of greenhouse gases (GHGs) into the atmosphere by human-fuelled activities such as increased fossil fuel consumption leading to the release of carbon dioxide (CO2), the increasing use of automobiles, the use of nitrogen base fertilizers, and rearing and breeding large methane-belching cattle. Greenhouse gases such as carbon dioxide, nitrous oxide, water vapor, halocarbons (chlorofluo-rocarbons and hydrofluorocarbons), methane, and ozone have the capability of absorbing infrared radiation from the Earths surface, thereby altering the heat balance of the Earth.

The gases later warm the Earth s surface by emitting trapped energy. When GHGs absorb radiation, the stratosphere becomes warm and then re-emits infrared radiation back to the Earths surface. This warming of the Earth's troposphere is commonly known as the greenhouse effect. Global warming potential (GWP) is usually expressed in relation to carbon dioxide, which is given a relative global warming potential of one. Methane, nitrous oxide, and hydrofluorocarbons are assigned a GWP of 23, 296, and 12,000 respectively. This means that methane is 23 times as potent a GHG as carbon dioxide, and nitrous oxide is 296 times as potent as carbon dioxide.

Many human processes ranging from industry, transportation, power stations, agriculture, fossil fuel development and usage, to residential and commercial activities have variously led to the production of high amounts of greenhouse gases, such as carbon dioxide, methane (CH4), nitrous oxide (N2O), water vapor, and chlorofluorocarbons (CFCs). Of these activities, agriculture contributes the largest amount of methane (40 percent) and nitrous oxide (62 percent), while the combination of industrial processes, power stations, fossil fuel processing and development, with residential and commercial activities contributing over 82 percent of the total carbon dioxide produced by the entire human activities.