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Global warming

Global warming means the gradual increase of the temperature of the earth's lower atmosphere. It is now know to be caused by an increase of greenhouse gases since the middle of the 19th century onwards.

More specifically, the temperature of the atmosphere near the earth's surface is warmed through a natural process called the greenhouse effect. Visible and shortwave light reaches the earth (from the sun) and pass naturally through the various layers of warm gases composed largely of water vapor, carbon dioxide, methane, nitrous oxide, and ozone. The greenhouse effect is where infrared light waves (a phenomenon of the visible and shortwave light) reflect off the earth's surface toward space but cannot easily pass through the layers of lower atmosphere. These layers are filled with greenhouse gases. This is ideal, as some of it becomes trapped and reflected downward, keeping the planet at an average stable temperature, about 16°C. This is a key element in making life possible on earth.

However, due to the continual growth in industry and transport based on the use of fossil fuels, and their expulsion into the atmosphere, there has been also a steady rise in the amount of suspended material in the natural greenhouse gases, increasing the amount of infrared rays that become trapped in the lower atmosphere. Since 1900 the average atmospheric temperature has risen 0.6°C, with the corresponding sea level has risen several centimeters. This is average temperature is continuing to rise.

The obvious impending consequences of global warming include the melting of polar ice, and resulting rise in sea level. This will mean (and can already be seen) coastal flooding; water shortages from places that depend on melted snow; serious disruption for agriculture; the extinction of animal and plant species as ecological niches disappear; and a chance for the a new Ice Age due to the possible switching off of the Gulf stream currents in the North Atlantic Sea.