[ALOCHONA] Impacts of seal level rise on Bangladesh

Impacts of seal level rise on Bangladesh Rajesh Sarker Climate change is an important issue nowadays. Various human activities are making the world hot to hotter. The ultimate result is global warming, i.e. climate change. Rising temperature in the atmosphere causes sea level rise and affects low lying coastal areas and deltas of the world. In 1990, Intergovernmental Panel on Climate Change estimates that with a business-as-usual scenario of greenhouse gas emission, the world would be 3.3 C warmer by the end of the next century, with a range of uncertainty of 2.2 to 4.9 C (Warrick et al., 1993). With rise in temperature, sea level will rise because of thermal expansion and ice melt. Sea level rise has various impacts on Bangladesh, a coastal country facing 710 km long coast to the Bay of Bengal. It already has affected Bangladesh by land erosion, salinity intrusion and loss in biodiversity. Its potential threats are coming even strongly in the future. Sea level rise will cause river bank erosion, salinity intrusion, flood, damage to infrastructures, crop failure, fisheries destruction, loss of biodiversity, etc. along this coast. Due to various human activities, carbon dioxide (CO2) and other greenhouse gases are accumulated in the earth's atmosphere, resulting in climate change. Rising temperature expand the ocean volume in two ways. Firstly, it melts mass volume of ice of the polar region and secondly, it causes thermal expansion of water of the ocean. Wigley and Raper (1987) comment that the relative contributions of thermal expansion and ice melting to this sea level rise are uncertain and estimates vary widely, from a small expansion effect through roughly equal roles for expansion and ice melting to a dominant expansion effect. These two factors increase volume of ocean water of the earth and rise in the sea level. 1. The main impacts of sea level rise on water resources are fresh water availability reduction by salinity intrusion. Both water and soil salinity along the coast will be increased with the rise in sea level, destroying normal characteristics of coastal soil and water. 2. Sea level rise would change the location of the river estuary, causing a great change in fish habitat and breeding ground. Penaid prawns breed and develop in brackish water, where salt water and fresh water mix. Sea level rise would turn this interface backward, changing habitat of prawn. 3. Salinity intrusion due to sea level rise will decrease agricultural production by unavailability of fresh water and soil degradation. Salinity also decreases the terminative energy and germination rate of some plants (Rashid et a!., 2004; Ashraf et a!., 2002). Ali (2005) investigated the loss of rice production in a village of Satkhira district and found that rice production in 2003 was 1,151 metric tons less than the year 1985, corresponding to a loss of 69 per cent. Out of the total decreased production, 77 per cent was due to conversion of rice field into shrimp pond and 23 per cent was because of yield loss 4. The SLR will inflict its impacts on Bangladesh in the coastal area and through the coastal area, on the whole of Bangladesh. About 2,500,8,000 and 14,000 km of land (with a corresponding percentage of2%, 5% and 10% with respect to the total land area of the country) will be lost due to SLR of O.lm, 0.3m and 10m respectively (Ali, 2000). The potential land loss estimated by IPCC (2001) is even worse. It reports 29,846 sq. km area of land will be lost and 14.8 million people will be landless by I-m SLR. (Figure-II & 12) Land loss leads to loss of agricultural land, loss of homestead, loss of road and other communication infrastructure and above of loss of wide range of biodiversity. One of the major causes of land loss is erosion. 5. Bangladesh is one of the salt producing countries of the world. Cox's Bazar coast of Bangladesh coastline is suitable for salt production. About 19,670 ha area has been used for salt production along the Cox's Bazar coast of the country. There are 216 salt pans, having an area of 8,153 ha only in Chakaria and Cox's Bazar Sadar thana of the district, producing 175,030 metric tons of salt annually (Hossain and Lin, 2001, p.19). This coastal industry is fully influenced by sea water and its level. A one metre sea level rise will inundate all the salt fields and will ruin the sectors. Salt farmers can't move upwards land for the purpose because, physical properties of the soil of the present salt field will not move backwards with sea level rise. About 20 million people are directly or indirectly related in salt production (Hossain and Lin, 2001, p.20) and! or trading in Bangladesh. Sea level rise, by inundating salt fields will force this huge number of people to be unemployed. This large population will try to find alternative profession, which is very hard or even impossible, in the case of present situation of Bangladesh. 6. All the tourist facilities in the coastal zone will be affected by sea level rise directly or indirectly. Tourism sector of Kuaka will suffer the most because all the facilities are very close to the coastline and the area is more vulnerable Comparative to Cox's Bazar and Chittagong. However, all the mentioned areas are highly vulnerable in terms of sea level rise related natural disaster, e.g. flood, storm surge, etc. 7. Sea level rise may increase the risk of health hazards like diarrhoea, cholera, etc. Cholera is an infectious disease of the small intestine of human beings and is common in the coastal area of Bangladesh. Water salinity of the coastal area of Bangladesh varies from 0 ppt to 20 ppt .Water salinity and its distribution in the coastal area are increasing with the increase of sea level rise (Faisal & Parveen, 2004; Alam, 2003; IPCC, 2001a; World Bank, 2000). With the increased density and distribution of salinity, cholera germs are getting favourable habitat and spreading in the coastal area. 8. The Sundarbans will be completely lost with 1 metre sea level rise (World Bank, 2000, p.63). Loss of the Sundarbans means great loss of heritage, loss of biodiversity, loss of fisheries resources, loss of life and livelihood and after all loss of very high productive ecosystem. Area of the Sundarbans, inundated by different scale of sea level rise. 9. Sea level rise, by reducing fresh water availability, reducing fisheries and agricultural production, eroding coastal land, losing biodiversity and by causing health hazards ,creates a danger situation for the people of Bangladesh. Again, 'most important to survival and well-being' is the basic needs of human being. Table: Impacts of sea level rise on the basic needs of the people of Bangladesh Basic needs. How sea level rise affects it Food. Rise in sea level would flood agricultural lowlands and deltas in parts of Bangladesh (Miller, 2004; Bennett et al, 1991) that will decrease food production, causing shortage of food. Only salinity intrusion due to sea level rise will reduce 0.2 million metric ton of rice production (WB, 2000). Cloths: Sea level rise will increase poverty. Increased poverty will decrease cloths buying capacity of the people of Bangladesh. Housing: In Bangladesh, 29,846 sq. km. area of land, will be lost and 14.8 million people will be landless by sea level rise (IPCC, 2001a), losing their house. Health: Sea level rise by extending coastal area and by increasing salinity in the area will increase the risk of cholera. It will accelerate flood intensity facilitating transmission of diarrheal disease (World Bank, 2000). Education: Sea level rise will cause destruction of infrastructure including educational institutes. Besides, students of flood, or other sea level rise affected family will leave School College, in search of work to support their family. Food, clothing, housing, health and education are the basic needs of the people of Bangladesh. Table-8 explains how sea level rise affects the basic needs of large number of people of the country. Affecting basic needs, sea level rise becomes a threat to food security and other well-being securities . Many of these people have been displaced from their homes in recent decades becoming 'ecological refugees'. Sea level rise will create such ecological or environmental refugees in the country, forming 'ecological marginalisation' (Homer-Dixon, 1998). Barnett (2003) states, 5.5 million people living on the Ganges delta in Bangladesh who will be forced to relocate with a 45 cm rise in sea level may seek to move inland within Bangladesh, but a significant number may seek to move to India and Pakistan-and previous migration of this kind has been a factor in violence in the region. Sea level rise induced environmental refugees may trigger the conflict. Nowadays 'Push back' is common news in Bangladeshi newspapers that means pushing Bengali speaking people from 'India to Bangladesh by Indian Border Security Force (BSF). Environmental refugees created by sea level rise will cause even worse situation that may trigger conflict between the two countries. Thus, sea level rise might be a threat to national security of Bangladesh.   http://nation.ittefaq.com/issues/2008/06/05/news0515.htm

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