The WWF reports another impact from melting ice in the form of contaminants. Before organic pollutants such as PCBs and DDT were banned, they were widely used during the mid-1900s. PCBs are poly-chlorinated biphenyls, a chemical mixture used in the past as coolant and as insulating fluid for transformers and capacitors. They are no longer used in the United States, but they still can be found in the environment. DDT stands for dichlorodiphenyltrichloroethane, which was a chemical pesticide used in the past but was also banned in the United

States. A significant amount of the long-lasting pollutants were transported by air and deposited on the glacial ice, where they have been stored all this time, locked in the ice. As the ice melts, these pollutants are being let loose into the atmosphere.


Another impact of melting glaciers is flooding. When melting occurs too rapidly, river banks can reach full capacity and overflow their banks. They can also form glacial meltwater lakes. If these lakes become too full, they can burst and cause a catastrophic flood in villages downstream. In fact, according to the United Nations Environment Programme (UNEP), there are currently 44 glacial lakes in Nepal and Bhutan alone that are in immediate danger of overflowing as a result of global warming. Specialists at the WWF report that in Peru, a huge chunk of glacier ice is ready to fall into a lake. If this should happen, it could cause a flood that could hurt or kill 100,000 people.

sea-Level Rise

If glaciers continue to melt at their current rate, they will add 0.008 to 0.02 inch (0.2-0.4 mm) to sea levels. It is possible, however, that this amount may be greatly underestimated. It has been recently discovered that the melting rates of Alaska's glaciers and the Northern and Southern Patagonian Ice Fields have greatly increased and are now adding an additional 0.01 inch (0.03 cm) each year. If glacial melt causes sea levels to rise, it will hurt coastal regions worldwide by increasing flooding and erosion, allowing salt water to enter aquifers and contaminate them. It will and also enter freshwater habitats, negatively impacting the life that is supported in these biomes. According to the WWF, the small sea-level rise experienced during the 1900s led to erosion and the loss of 39 square miles (100 km2) of wetlands per year in the Mississippi Delta.

0 0

Post a comment