The evacuation of all 2,000 inhabitants of Cataret Island marked the beginning of the end for many low-lying atolls in the Indian and Pacific Oceans. Rising sea levels have flooded the food and fresh water sources on this small island off Papua, New Guinea, and made it necessary to relocate the inhabitants to nearby Bougainville.
According to IPCC, the Intergovernmental Panel on Climate Change, sea levels worldwide will rise up to 88 cm (34.6 in.) by the end of this century. Other studies indicate the rise could be lower or much higher than that, depending on the pace of global warming.
A 3 ft (1 m) sea level rise threatens the existence of many island nations in the Pacific and Indian Oceans. Many of these coral atolls are only 6 or 7 ft (2m) above sea level. While a 3 ft (1m) rise in the sea would not totally submerge every one of these islands, many of them would become uninhabitable due to sea water intrusion into the fresh water aquifer, salt water swamping of coconut and taro fields, washing out of roads, hospitals, and public utilities. Many of these islands are already trying to cope with these destructive changes. In addition to Cataret, several other low islands are making plans to relocate their populations. New Zealand has agreed to accept refugees from a small island in the Vanuatu group that is currently undergoing flooding from storms and a rising sea level, and may soon have to be evacuated.
Among the islands under threat of submersion by the end of this century are the Maldives in the Indian Ocean, hundreds of atolls in the Pacific around New Guinea, the Cook Islands, Fiji Islands, Solomon Islands, and Marshal Islands. Kiribati, Tuvalu, and Vanuatu all have surrounding atolls that have been partially or completely submerged by rising seas. Low-lying cities such as Shanghai, only 6 ft (2m) above sea level, and the heavily populated coast of Bangladesh that lies only a few feet above sea level, will also be adversely affected by the steady encroachment of the sea. Sea water intrusion into Asian rice paddies in fresh water wetlands will threaten the food supply in that part of the world.
World sea level has risen 8 inches (20cm) in the past century, but global warming has greatly accelerated the process in the past 20 years. Projected air temperature increases for the 21st century range from 2.0 to 11.5 degrees F (1.1 to 6.4 degrees C). NASA satellite imaging shows that the polar ice cap is melting at the rate of 9% per decade. The Greenland Ice Sheet is disappearing equally fast, and almost all the glaciers of the world are in retreat.
Rising sea levels are caused by two main factors: (1) melt water from ice caps, ice sheets, and glaciers, and (2) thermal expansion of the sea water (as water gets warmer, it expands and takes up more space). Both ice melt and thermal expansion are products of global warming. Scientists estimate that melt water from ice caps, ice sheets, and glaciers contribute approximately 25% to the current increase in ocean volume, while thermal expansion is responsible for 50%. Exactly what makes up the remaining 25% contribution is not clearly understood. But to sum up, as air temperature rises due to global warming, ocean temperatures go up, ocean volume increases, and the sea level continues to rise.
Most of the world’s seacoast cities, ports, and recreation areas will eventually be overtaken by rising sea levels. New York, New Orleans, Miami, London, Amsterdam, and Venice are among world cities that may be working hard to “hold back the sea” in the not too far distant future.
About Gordon
While the Earth has always endured natural climate change variability, we are now facing the possibility of irreversible climate change in the near future. The increase of greenhouse gases in the Earth?s atmosphere from industrial processes has enhanced the natural greenhouse effect. This in turn has accentuated the greenhouse ?trap? effect, causing greenhouse gases to form a blanket around the Earth, inhibiting the sun?s heat from leaving the outer atmosphere. This increase of greenhouse gases is causing an additional warming of the Earth?s surface and atmosphere. A direct consequence of this is sea-level rise expansion, which is primarily due to the thermal expansion of oceans (water expands when heated), inducing the melting of ice sheets as global surface temperature increases.
Forecasts for climate change by the 2,000 scientists on the United Nations Intergovernmental Panel on Climate Change (IPCC) project a rise in the global average surface temperature by 1.4 to 5.8°C from 1990 to 2100. This will result in a global mean sea level rise by an average of 5 mm per year over the next 100 years. Consequently, human-induced climate change will have ?deleterious effects? on ecosystems, socio-economic systems and human welfare.At the moment, especially high risks associated with the rise of the oceans are having a particular impact on the two archipelagic states of Western Polynesia: Tuvalu and Kiribati. According to UN forecasts, they may be completely inundated by the rising waters of the Pacific by 2050.According to the vast majority of scientific investigations, warming waters and the melting of polar and high-elevation ice worldwide will steadily raise sea levels. This will likely drive people off islands first by spoiling the fresh groundwater, which will kill most land plants and leave no potable water for humans and their livestock. Low-lying island states like Kiribati, Tuvalu, the Marshall Islands and the Maldives are the most prominent nations threatened in this way.“The biggest challenge is to preserve their nationality without a territory,” said Bogumil Terminski from Geneva. The best solution is continue to recognize deterritorialized states as a normal states in public international law. The case of Kiribati and other small island states is a particularly clear call to action for more secure countries to respond to the situations facing these ‘most vulnerable nations’, as climate change increasingly impacts upon their lives.