This Weather topic submitted by Blake (Blakeshreds@hotmail.com) on 1/14/02.
EarthÕs Glaciers are Disappearing
Glaciers all around the world are melting. Research done on glaciers since the 1800s, shows that glaciers are retreating dramatically. This may have a Profound effect on the environment. I am interested in this topic because I have many questions of how this could affect me, my future, and the world I live in. In this paper, I first provide data showing the overall retreat of glaciers. Second, I will give the possible causes of glacial retreat. Finally, the potential impact of the widespread melting of glaciers is discussed.
All together, the worldÕs glaciers are now shrinking faster than they are growing. There have been many reports, mostly from the past two decades, that clearly support the glacial retreat. It is unknown when the melting began. It may have been since the Industrial Revolution in the 18th century, when factories, farms, automobiles, and power plants first started releasing heat- trapping gasses in to the atmosphere, or even since the Little Ice Age, an unusually cold period during the 1500s and 1600s. The last ice age, when it is believed that much of the EarthÕs surface was been covered by ice, was at its maximum extent 18,000 years ago. (McCarthy, 2000) The meltdown of many glaciers began accelerating in the early 1980s. Records on the glacier mass in western EuropeÕs highest mountain range have been kept since 1850. The records show that the glacier mass on these mountains, including the Caucasus, is over half gone. Other Mountains have similar records, such as Mt. Kilimanjaro. Standing tallest in Africa, it has less than 25 percent the glacial area it had a century ago. Other records have been kept on arctic and Antarctic ice. The oldest ice on Antarctica is said to be at least one half of a million years old. Scientists disagree on how quickly it is melting. On the other hand, observers who journeyed to the North Pole via submarine during the summer of 2000 found no ice. There has been significant thinning of Arctic sea ice since the 1960s. It has reportedly shrunk about 6 percent between 1978 and 1996. (McCarthy, 2000) Also, a consistent data pattern in the North Hemisphere river and lake conditions show that they remain ice free for two weeks longer each year than a century ago.(Lemonick, 20001)
Scientists dispute over the causes of glacial meltdown. Although scientists no longer doubt global warming is happening, some are unsure whether itÕs causing the retreat of glaciers. A common theory of global warming is that it is a result of human activity. Many believe humans influence the EarthÕs Climate. Some scientists say we do so by releasing carbon dioxide and methane from fossil fuel combustion into the atmosphere. The 1990s were the hottest decade recorded. The fact that the world is getting warmer is the only possible cause to glacial meltdown and other changes in the environment, such as changes in migration of plants and animals. There are also disputes over what is causing warmer temperatures. Some say itÕs acid rain caused by emissions of sulfur dioxide, others believe the effects of the El Chichon and Mount Pinatubo volcanic eruptions have caused these warmer temperatures.(Lemonick, 2001) The IPCC says that by the year 2100, average temperatures will increase between 2.5 degrees F and 10.4 degrees F. (Lemonick, 2001) Still, scientists think that El Nino may be linked to the acceleration of glacial meltdown in Ecuador and Peru. (ŌTropical GlaciersĶ, 2000)
There is a drastic impact on the environment that will result from the widespread melting of glaciers. Glaciers are very important to humans as well as plants and animals. For example, In the Indian subcontinent the Indus, Ganges and Brahmaputra rivers provide water for a tenth of all humanity. Up to 70 percent of their dry- season flow is supplied by Himalayan ice fields. Unfortunately these glaciers are receding by approximately 20 meters per year. If these rivers become seasonal, the many people who depend on them will no longer be able to survive. Also, many mountain species of plants and animals have to migrate out of their natural habitat to keep up with their preferred temperature zone. The dilution of the salt content of the sea which is caused by melting ice caps could result in slowing or stopping major ocean currents, and this could prevent the warming effects of these currents on other geographic regions. Seas may rise as much as three feet, causing vast areas of densely populated land to be uninhabitable and crops destroyed, due to melting of Arctic and Antarctic land ice. The loss of the earthÕs ice in general could effect the worldÕs temperature because ice cover also acts as a protective mirror to the sunÕs heat.
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