An example of how global warming changes the habitat of plant and animals is exemplified by the precarious situation of polar bears. Due to global warming, the ice covering the Artic Ocean forms later and later in the season, shrinking the ice sheet that polar bears need for hunting. This, in turns, threatens the very survival of polar bears as a species.
Thursday, November 26, 2009
Some of our most dramatic evidence of the melting of ice glaciers from global warming comes from Greenland where the rate of melting of its glacier ice sheet has doubled during the period of 1996 to 2005. The above photograph shows the amount of seasonal ice melting in 1992 (on the left) and 2002 (on the right).
Skeptics of the potential of a rise in sea levels from global warming have pointed out that a melting of sea ice would not cause a rise in sea levels. For there to be a cause for concern about a rise in sea levels, they have argued, one would have to see a melting of the ice covering the land masses of Greenland and Antarctica. And previously, there had not been evidence of the melting ice sheet of Antarctica. In more recent years, however, there has been sudden dramatic evidence of the melting of the ice sheet covering Antarctica. This has included a cracking appearing across the main ice sheet and significant portions of the ice sheet of West Antarctica melting and breaking off.
According to the International Panel On Climate Change (IPCC), the glaciers of the Himalayan Mountains are melting rapidly and could be gone completely by 2035. They have also stated that the rate of melting is increasing. This is significant because, as shown in the second photograph above, it is the snow melting of the Himalayan Mountains that provides the fresh water for much of Asia, including such major rivers as the Ganges in India.
The melting of the glaciers throughout the Andes Mountains of South America presents one of the clearest evidence of global warming. In Bolivia, it is estimated that the glaciers have shrunk by 60 percent since 1978. In Venezuela, the glaciers have all but disappeared. One estimate is that the Andean glaciers overall have shrunk by 30 percent or more in the last 25 years.
Mt. Kilimanjaro in Africa has lost 82 percent of its snow-topped glacier since 1912. Scientist estimate that if current trends continue, this 12,000 year old glacier on top of Kilimanjaro could be completely gone by the year 2020. It is not clear whether this melting of the snows of Kilimanjaro is a direct result of global warming or the indirect result of climate change causing less moisture in the tropics due to global warming. Which ever the cause, the melting of the snows atop Mt. Kilimanjaro indicates a dual trend of temperature rise and less moisture in the tropics. While the result is more noticeable for the glacier atop Mt. Kilimanjaro, what might be more significant on the adverse effects such warming and less moisture in the tropics could have on even larger eco-systems such as the Amazon rain forest. As the larger eco-systems are affected, this could have the feed-back result of triggering even more global warming and climate change.