The main cause of global warming is the increase of greenhouse gases in the earth's atmosphere. This creates what is known as the greenhouse effect which heats the earth by reducing the level of solar rays that are able to escape from our atmosphere.
Although the greenhouse effect is essentially a vital factor in supporting life on earth by keeping our atmosphere warm enough to support life, human activities are contributing to the quantity of greenhouse gases providing an artificial increase in the intensity of the greenhouse effect.
An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitaton, probably including expansion of subtropical deserts. The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.
Although global warming may only increase the globe's average temperature by a few degrees, this could have disastrous effects for sea levels, wildlife and human existence.
Global warming, caused by the burning of fossil fuels, has resulted in substantial melting of the polar ice-caps.
