GLOBAL WARMING

Global Warming

Global Warming

Introduction

Global warming can be simply defined as "human-induced climate change" (Lutz, et al., 2001). Global warming takes place because of increase of greenhouse gases in the environment. These gases are abundant due to the contribution of several factors. Global warming is expected to boost the average temperature of the surface of the Earth; change precipitation patterns and raise sea levels (Lutz, et al., 2001). There are many potential impacts of these changes. The Earth could see an increase in extreme weather and will have impacts on humans, animals, and ecosystems (Lutz 2001, Godrej 2001).

There is a lot of uncertainty as to how much and how fast the climate will change (Lutz, 2001). There is also debate about how serious the consequences will be (Lutz, 2001). Since all of the nations in the world contribute equally to the emissions of greenhouse gases (Lutz 2001), the solution will have to come on a global basis (Godrej, 2001).

The Greenhouse Effect

The greenhouse effect is rather simple to understand. Take the name, greenhouse effect. Think of the Earth as one big greenhouse. The glass walls of a greenhouse let light in, but trap heat inside. The atmosphere constitutes the glass walls (Lutz, 2001). This is a natural occurrence. There are gases in the atmosphere that let in light from the sun, but absorb the outgoing heat from the Earth's surface and emit that heat in all directions (Lutz, 2001).

Greenhouse gases make up less than 1% of the Earth's total atmosphere (Lutz, 2001). The most important greenhouse gas is water vapour (Godrej, 2001). Water vapour is not directly affected by human activity, but an increase in the other gases creates more surface heat, resulting in the evaporation of more water into the atmosphere (Lutz, 2001). Research has shown that this has already begun to happen, with a 2% increase in the amount of water vapour in the atmosphere (Godrej, 2001). Other important greenhouse gases are carbon dioxide, methane, nitrous oxide, and halocarbons (Lutz, 2001).

Methane is released into the atmosphere by livestock, leaks in natural gas pipelines and coalmines, and anaerobic respiration in rice paddies (Lutz, 2001). The atmospheric lifetime of methane is about 12 years. Methane is primarily removed form the atmosphere by chemical reactions (Lutz, 2001).

The largest factor in the release of nitrous oxide into the atmosphere is agricultural nitrogen-fertilizer (Lutz, 2001). Other factors include industrial processes and livestock feed lots (Lutz, 2001).

The most important halocarbon to contribute to global warning is chlorofluorocarbons (CFCs) (Lutz, 2001). CFCs are not produced naturally. They are used in aerosol sprays, refrigeration and air conditioning units, and some artificial foam (Lutz 2001, Godrej 2001). Historically, industrial nations have been responsible for releasing the most CFCs into the atmosphere. Currently, the levels have decreased with the amendments made by the Montreal Protocol on Substances that Deplete the Ozone Layer to phase out the production of these chemicals (Lutz, 2001). It is important to note, however, that the chemicals used to replace CFCs are still, to a lesser degree, ...