Long Term Effects of Global Warming

1. Long Term Effects of Global Warming Jack Langhenry

2. Extreme Weather Increasing temperatures could cause the weather to become less predictable. Increased temperature will likely result in greater amounts of precipitation, but other effects are difficult to predict. However, many scientists predict that global warming will result in an increase of hurricanes.

3. Extreme Weather The proportion of hurricanes reaching categories 4 or 5 (wind speeds above 56 meters per second) has risen from 20% in the 1970s to 35% in the 1990s. Hurricanes modeled under warmer conditions with higher CO2 levels will result in more intense hurricanes. Warmer temperature will also cause increased evaporation of the oceans. Increased evaporation could lead to heavier rainfall and more erosion. This could cause desertification in tropical areas that have been deforested.

4. Retreat of the Glaciers Since 1980, glacier retreat has increased greatly. Excluding ice sheets in the Arctic and Antarctic, the area of glaciers has decreased by 50% worldwide since the end of the 19th century. The loss of glaciers causes landslides, flashfloods and glacial lake overflow. Many glaciers are being lost to melting due to global warming. Glacier retreat has also been observed in Greenland and the Antarctic.

5. Oceans and Sea Level Rise Increasing global temperatures causes the water of the oceans to expand in volume. Sea levels are also rising due to the melting of Arctic and Antarctic glaciers. From 3000 years ago to the start of the 19th century, the sea level was almost constant, rising at 0.1 to 0.2 mm/yr. Since 1900, the level has risen at an average of 1.7 mm/yr. Two theories exist as to how rise in sea level will occur: Some predict that sea levels will rise gradually by 59 cm this century. Others believe that historical evidence suggests that a 2-3 degree increase in temperature could lead to a much more dramatic rise in sea level.

6. Shutdown of Thermohaline Circulation The Thermohaline Circulation is the global density driven circulation of the oceans. This circulation is caused by water with high saline concentration. Melting of the polar ice caps could increase the freshwater content of the oceans which will decrease the salinity of the oceans. This could cause cooler climates in Ireland, Britain, Iceland and Scandinavia.

7. Abrupt and Irreversible Effects of Global Warming Loss of polar ice caps could lead to a rise in sea level which could cause major changes in coastlines and the flooding of low lying islands and river deltas. A rise in the average global temperature of 3.5�C is predicted to result in the extinction of 40-70% of species on earth.

8. Future of Polar Animals Studies suggest that global warming is causing a decrease in the population of polar bears. Polar bears populations have been reduced by about 25% over the last 20 years. Scientists say that the polar bears are also becoming increasingly thinner due to an increased struggle for survival. Female polar bears are now less likely to give birth to more than one cub at a time and the species may become extinct soon. The average temperature of the Canadian Arctic has risen about 4�C over the last 50 years. This environment is becoming increasingly less inhabitable for polar bears who are designed for life in extremely cold climates. Some scientists believe that polar bears could be extinct in the wild within the next century.

9. Future of Polar Animals Walrus calves are being stranded by melting sea ice in the Arctic Ocean. Increasing polar warming may be forcing walrus mothers to abandon their pups due to retreating sea ice. If walruses and other marine mammals are unable to raise their young in shallow waters as opposed to resting on platforms of sea ice, their populations will decrease rapidly and may disappear.