2. 1 Impacts of flood Bangladesh is located on a floodplain of three major rivers (Ganges-Brahmaputra-Meghna) and their numerous tributaries. As a result of that flooding in Bangladesh is a regular feature and has numerous adverse effects, including loss of life through drowning, increased prevalence of disease, and destruction of property. One-fifth of the country is flooded every year, and in extreme years, two-thirds of the country can be inundated. In a normal year, 20-25% of the country is inundated by river spills and drainage congestions. Approximately 37%, 43%, 52% and 60% of the country is inundated with floods of return periods of 10, 20, 50 and 100 respectively. From historical point of view, it has been observed that the frequency, intensity and magnitude of flood have increased as well. Since 1954, 48 small, medium and big floods have struck Bangladesh. Among those, 7 events were severe where more than 30% of land area was inundated. When a major disaster has stuck, the whole economy suffered. Agricultural sectors suffered probably more than sectors. Devastating floods of 1987, 1988 and 1998 inundated more than 60% of the country. The 1998 flood alone caused 1,100 deaths, inundated nearly 100,000 km2, rendered 30 million people homeless, damaged 500,000 homes and caused heavy losses to infrastructure. The resulted damages and losses was over $2 billion (4.8 percent of GDP), approximately equally split between infrastructure, agriculture, and industry/commerce. In 2004, floods inundated 38% of the country.
2.2 Impacts of cyclone: The Bay of Bengal is a known breeding ground of tropical cyclone and hit the coastal area of Bangladesh during pre-monsoon (April and May) and post-monsoon (October and November). The reason behind this is its somewhat unique location and topography (that creates an inverted funnel effect), and because of the low (though growing) capacity of its society and institutions to cope with such extreme events. Cyclones originate in the deep Indian Ocean and track through the Bay of Bengal where the shallow waters contribute to huge tidal surges when cyclones make landfall. Over the last 50 years, 15 severe cyclones with wind speed ranging from 140 to 225 km/hr have hit in the coastal area of Bangladesh of which 7 hit in pre-monsoon and rest in the post-monsoon season. Historical record of Cyclone formed in Bay of Bengal revealed that 15 most damaging cyclones have struck Bangladesh vary badly. Among those 4 were catastrophic and killer cyclones which struck in 1919, 1970, 1991 and 2007. A cyclone in 1970 resulted in close to 300,000 deaths, and another, in 1991 led to the loss of 138,000 lives, although in recent years greater success in disaster management has significantly reduced the lives lost. Despite that Bangladesh has been threating by cyclones almost every year which has a negative impact on national development.
2.3 Impacts of drought Bangladesh experiences major droughts once in 5 years. Droughts at local scale are much more frequent and affect part of the crop life cycle. The western part of the country is vulnerable to drought during pre-monsoon period. Severe drought occurred in the country. During the last 50 years, Bangladesh suffered about 20 drought conditions. The drought condition in north-western Bangladesh in recent decades had led to a shortfall of rice production of 3.5 million tons in the 1990s. If other losses, such as, to other crops (all Rabi crops, Sugarcane, Tobacco, Wheat, etc.) as well as to perennial agricultural resources, such as, Bamboo, Betel nut, fruits like Litchi, Mango, Jackfruit, Banana etc. are considered, the loss will be substantially much higher. Current Severe drought can affect yield in 30% of the country, reducing national production by 10%. Temperature increase of 0.5°C and annual rainfall reduction of 5% could reduce runoff into the Ganges, Brahmaputra and Meghna Rivers by 14%, 11% and 8%, respectively. With 12% reduction in runoff, the population living in severe drought-prone areas increases from 4% to 9% under moderate climate change.
3. Future climate change impacts on sustainable development in Bangladesh Bangladesh is already vulnerable to many gradual change phenomena of climate change as well as climate change related extreme events. It is expected that climate change will bring changes in characteristics of gradual change phenomenon and natural hazards which will result changes in physical, social and production system. It is estimated that climate change could affect more than 70 million people of Bangladesh due to its geographic location, low elevation, high population density, poor infrastructure, high levels of poverty and high dependency on natural resources. On the other hand, a 1 m rise in sea level would inundate 18% of Bangladesh’s total land, directly threatening 11% of the country’s population with inundation. Over the course of the 21st century and beyond, sea level rise will threaten hundreds of thousands if not more than a million hectares of agricultural land . About 252,000 tons would be lost by 2075 (WRI, 2001). Threatening the richest and most productive region of the country, sea level rise could have dramatic consequences for the Bangladeshi economy. Above all indicate that climate change will affect all the aspects of sustainable development in Bangladesh.
4. Cost of climate change and sustainable development in Bangladesh Climate-related disasters continue to result in large economic losses, reducing economic growth and slowing progress in reducing poverty. In Bangladesh, the direct annual costs from natural disasters to the national economy—in terms of damages to infrastructure and livelihoods and losses from forgone production—have been estimated at 0.5 percent to 1 percent of GDP. Since the sixties, Bangladesh has invested $10 billion on disaster reduction measures, both structural and non-structural, and enhanced its disaster preparedness system. These measures have significantly reduced damages and losses from extreme events over time, especially in terms of deaths and injuries.