the indian ocean has seen some dramatic changes owing to the effects of global warming and climate change. The major effects of global warming have been the rise of waters temperature, and also the rise in the water level. Researchers have shown not only a general warming of the surface of the Indian Ocean, but also warming of about 3.6 degrees F (2 degrees C) over the last 40 years, in the region of 40 degrees S and 50 degrees S, down to a depth of 262 ft. (800 m.). A study by the National Aeronautics and Space Administration (NASA) showed that tradewinds that cover the southern part of the Indian Ocean have also weakened 1992-2000 so much that there has been up to a 70 percent reduction in up-welling and cool currents. Scientists are also worried about the survival of many of the marine turtles in the Indian Ocean, for which global warming and climate change represent yet another threat.
Most of the focus of world attention on global warming in the Indian Ocean remains focused on the potential loss of land through rising sea levels. This is because there is much low-lying land around the Indian Ocean. The Republic of the Maldives, an archipelago of 1,190 islands (202 of which are inhabited), is at risk of submersion if there is a significant rise in the level of the Indian Ocean. With the Maldives having an elevation of less than 8 ft. (2.5 m.), the government of the Maldives has been actively campaigning for countries around the world to reduce greenhouse gas emissions.
Although the Maldives is at greatest risk of being entirely submerged, many other islands in the Indian Ocean are also under threat. These include the Lac-cadive Islands, and some of the islands in the Andaman and the Nicobar groups (all parts of India), as well as islands of the British Indian Ocean Territory, especially in the Chagos Archipelago. Some of these islands, too, have the very real risk of total submersion with rising water levels. There is also a concern about islands in the Seychelles, Mauritius, and the French island of Réunion. Parts of mainland Asia are also at risk, especially Bangladesh, which is suffering increasingly from floods, and the land around the mouth of the Irrawaddy in Myanmar (Burma).
The problems in Bangladesh, one of the most densely-populated countries in the world, have been serious for many decades, and further floods threaten to cause even longer-term economic problems. Many geographers believe that global warming has led to more frequent floods and cyclones, regularly displacing many farmers who lived on the Ganges-Brahmaputra Delta. The Sunda Islands, off the west coast of Sumatra, have also seen a rise in flooding that has led to increased breeding of mosquitoes and the rise in the prevalence of insect-borne diseases such as malaria and dengue fever, problems also exacerbated by more flooding in Myanmar, which has become more regular since the 1980s. Prolonged flooding would seriously undermine the agricultural base of both Bangladesh and
Myanmar, resulting in worsening coastal problems. As the coastline is battered by the Indian Ocean, it is expected that some of the farmers will move inland, threatening, in the case of Bangladesh, the Sundar-bans, which is currently the largest mangrove forest in the world, home of the Royal Bengal tiger, and other fauna and flora.
The most dramatic instance of flooding in the Indian Ocean was caused by a tsunami that caused devastation to parts of northern Sumatra and also along the coasts of Sri Lanka and Thailand on December 26, 2004. It resulted in the deaths of some 230,000 people, of whom the majority (168,000 by some estimates) were from Indonesia. The worst affected areas were the Indonesian province of Aceh, and the town of Galle in Sri Lanka, with deaths in many other countries, including an estimated 289 people in Somalia. There was devastation to the coastline, and loss of marine life, including shrimp off the west coast of Sumatra and Thailand. Although trade had long linked the countries of the Indian Ocean, the 2004 tsunami emphasized to the people in the region, the environmental problems in the area, and the links between global warming and a greater prevalence of flooding. The tsunami caused casualties in 15 countries.
Researchers have turned to studying the ocean currents. Although the water of the Indian Ocean has received warm saline water from the Red Sea past the Gulf of Aden, the rising water temperature has caused a decline in the diversity of fish in that part of the Indian Ocean. Global warming has also been suggested as a possible cause of changes in the temperature of the Agulhas Current, affecting the population of sardine and tuna off the coasts of southern Africa.
sEE ALso: Agulhas Current; Hurricanes and Typhoons; Indonesia; Oceanic Changes; Sea Level, Rising.
BIBLIoGRAPHY. S.S. Ali and R.R. Ramchandani, eds., India and the Western Indian Ocean States: Towards Regional Cooperation in Development (Allied Publishers Private Limited, for the International Seminar Publication Committee of Bombay University, 1981); Stefan Hastenrath, Climatic Atlas of the Indian Ocean (Madison University Press, 1979); Ann Morris and Heidi Larson, Tsunami: Helping Each Other (Millbrook Press, 2005); Meera Path-marajah and Nikki Meth, "A Regional Approach to Marine
Environmental Problems in East Africa and the Indian Ocean," Ocean Yearbook (v.5, 1985); N. Patrick Peritore, Third World Environmentalism: Case Studies from the Global South (University of Florida Press, 1999); G.S. Roonwal, The Indian Ocean: Exploitable Mineral and Petroleum Resources (Springer Verlag, 1986); D.R. Sikka, Indian Ocean and Climate (Society for Indian Ocean Studies, 2000); Aihong Zhong, et al., On Aspects of the Mean Climatology and Tropical Interannual Variability in the BMRC Atmospheric Model (BAM 3.0) (Bureau of Meteorology Research Centre, 2006).
JUSTIN CORFIELD Geelong Grammar School, Australia
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