Around the world, glaciers are also rapidly diminishing. According to Al Gore�s An Inconvenient Truth, �almost all of the mountain glaciers in the world are now melting.� Glacier National Park, for instance, has hardly any remaining glacier. Mt. Kilimanjaro is another prime example; the snows atop this African mountain have been receding since the turn of the century, and are predicted to one day be completely gone. The glaciers of most concern, however, are the glaciers on the Himalayas. The natural �melt of these glaciers is a large and reliable source of water for China, India, and much of Asia, and these waters form a principal dry-season water source.� (Wikipedia.) However, scientists fear that with increased global temperatures, these glaciers would melt faster, resulting in greater water flow for a few decades, and then consequentially run out all together. The ice on the Himalayas provides approximately 50% of drinking water to approximately 40% of the world�s population. (An Inconvenient Truth by Al Gore.) Therefore, if these glaciers completely disappear, an enormous amount of people would face a severe water shortage.
In addition to melting glaciers, various ecosystems are being dramatically altered. Organisms in any given ecosystem have adapted to their regional climate. Global warming has already begun to affect these organisms by changing the climate they live in. Most noticeable changes have occurred in high-altitude and high-latitude ecosystems, (such as the Arctic.) One study of a range of 59 plants, 47 invertebrates, 29 amphibians/reptiles, 388 birds, and 10 mammal species, showed that approximately 80% had some sort of change in their natural patterns that were consistent with global warming predictions. These changes include variations in migration patterns, breeding seasons, spreading to higher elevations and latitudes, as well as changes in their physical size and population. The other 20% however, displayed opposite changes. This is a prime example of how global warming can be very predictable, but at the same time extremely surprising. For some of these species, climate alterations could actually be beneficial; some will flourish with warmer temperatures and changes in the weather. However, other species may be forced to extinction because they cannot survive in the new climate. Already endangered species have an especially high risk of extinction.
Rainforests in particular are affected by global warming � mainly by droughts brought on by increasingly stronger and more frequent El Ni�o conditions. These droughts leave the usually moist forests dry and prone to fire. Normally, one hectare (about 2.5 acres) of rainforest can absorb about 31kg of carbon dioxide in one day. (Data taken from an Australian tropical rainforest.) However, when these rainforests become dry from drought, they begin to emit carbon dioxide. Some rainforests burn in massive forest fires, releasing carbon dioxide as a product, while the others that do not burn begin to give off about 12kg carbon dioxide a day per hectare. Not only will climate changes alter the health and productivity of these rainforests, but they could also alter the �geographic range of certain tree species.� (epa.gov)