Global warming is one of the major environmental issues facing the world today. Global warming refers to an average increase in the Earth's temperature, which in turn causes changes in climate. An increase in the temperature of the Earth�s surface may lead to changes in rainfall patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans. One cause for Global Warming is called the Greenhouse Effect. The Greenhouse Effect results from a four step process.
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First, sunlight radiates from the sun, through space, to Earth's atmosphere. Second, the sunlight enters the atmosphere and hits Earth. Some of it turns into heat energy in the form of infrared light. The heat is absorbed by surrounding air and land, which in turn makes it warm. Third, infrared rays, which are remitted into the atmosphere, are trapped by greenhouse gases.
Finally, the gas then absorbs the light and is remitted back to the Earth's surface and warms it even more. Human activities have altered the chemical composition of the atmosphere through the buildup of greenhouse gases � primarily carbon dioxide, methane, and nitrous oxide.
While on average the globe will get warmer and receive more precipitation; individual regions will experience different climatic changes, with different consequences for the local environment. Those changes which are the subject of greatest concern are: a rise in sea level, climatic changes and more extreme weather events, and a greater potential for heat-related illnesses and deaths.
First, an increase in the Earth�s surface temperature is causing mountain glaciers the world over to recede resulting in a rise in sea levels. According to the Union of Concerned Scientist of USA (ucsusa) the Arctic ice pack has lost about 40 percent of its thickness over the past four decades. Global sea level is rising about three times faster over the past 100 years compared with the previous 3,000 years (ucsusa).
Melting of glaciers could raise sea levels and devastate flat and low-lying coastal regions. Fresh water from glaciers could also disrupt the churning flow of sea water that normally blunts extreme temperature changes. �The ocean�s ice cover has thinned by an average of four feet- some 40 percent- since the 1960s, and satellite data show that the ice�s reach has receded 5 percent.