Bangladesh lies north of the Tropic of Cancer, located between 20°34′ N and 26°33′ N and 88°01′ E and 92°41′ E longitudes. Located in the north-eastern part of the Indian subcontinent, it is bordered by India on the west, north and east, except for a small portion in the south–east by Myanmar. The Bay of Bengal occupies the entire south. Bangladesh is a country of about 147,570 sq. km., including inland and estuarine water. Three mighty Himalayan rivers – the Ganges, the Brahmaputra and the Meghna drain into the Bay of Bengal. Bangladesh is deltaic in origin, with a flat terrain of low relief. Bangladesh has three types of landscapes: floodplains spread over 80% of the country’s land area, terraces covering 8% and hills dispersed over 12% of the land area of Bangladesh. The total population of Bangladesh is 140 million with highest density of population in the world (948/sq. kilometre). Bangladesh has made significant achievement in poverty reduction and development. In the 1990s, the country achieved one of the fastest rates of poverty reduction in the world, almost equal to that of Uganda and Vietnam, countries which are often lauded for the poverty reduction achievements (DFID, 2003). Bangladesh is primarily an agro–based economy. However, in recent years, a number of issues are threatening the sustainable development of the country. These issues include climate change, arsenic contamination, shrinking land:man ratio due to urbanization, land quality loss and river bank erosion. This paper will highlight concerns related to these issues.
IPCC impact assessments identify Bangladesh as one of the most susceptible countries of the world. These impacts range from an overall increase in sea level, atmospheric temperature and rainfall to more intense natural disasters in the form of floods, cyclones, storm surges, drought and others consequential impacts. Many projections suggest greater variability in future monsoon patterns which will have severe impacts upon agriculture. This will manifest from either by excess flow or severely low flows and draughts in other years. Coastal areas of Bangladesh will be affected by drainage congestion due to raised riverbeds, higher water levels, salinity intrusion, reduced drainage, higher sea level etc. The coastal areas face the primary risk of inundation. Sea level rise will directly affect vast coastal area and flood plains of Bangladesh. With 10 cm sea level rise which is likely to happen in 2020 will inundate 2% of the country; 25 cm rise in sea level will inundate 4 % of the country by 2050. With a projected 1 m sea level rise, 17% totalling about 30,000 sq. km. area of land will be inundated and around 14.8 million people will become landless, losing their home.
While climate change impacts are slowly become visible, more imminent threat like arsenic poisoning is crippling people in a large part of the country. Arsenic was first detected in groundwater in 1993. Contaminated wells exceeding the Bangladesh standard of 0.05 mg/l have been identified in 41 of the country's 64 districts and in about 30% of the total number of hand pump tube wells. It has been estimated that a population of 25 to 36 million are exposed to arsenic contamination and related health risks. Shallow aquifer containing arsenic is the main source of irrigation water during the dry Boro season. Approximately 95% of all groundwater extracted is used for irrigation, mainly for Boro rice production. Recent research findings indicate that arsenic is entering into food chain through the irrigation water.
Shrinking land:man ratio due to rapid conversion of arable lands to other uses poses greater imminent threat to agricultural sustainability. Rapid urbanization is one of the major causes of land conversion. The urban population is expected to reach 50 million by 2010 and nearly 80 million in 2020. The urban population of capital Dhaka is expected to reach 14-16 million by 2010 and 15-20 million by 2020. Urban growth centres will put enormous pressure on country’s arable land.
Riverbank erosion is a perennial problem in this country. The Bangladesh Water Development Board (BWDB) has estimated about 1200 km of riverbank is actively eroding and more than 500 km face severe problems related to erosion. It is estimated that river erosion annually affects about 100,000 people living on the riverbanks. This particular problem imposes significant social hardship as they loss homestead and agricultural land.
The Government of Bangladesh is addressing these issues with utmost urgency with a view to mitigating the impacts in all possible ways and ensuring sustainable development of Bangladesh.
