Bangladesh is a low-lying, riverine country located in South Asia with a largely marshy jungle coastline of 710 km on the northern littoral of the Bay of Bengal. Formed by a delta plain at the confluence of the Padma, Jamuna, and Meghna Rivers and their tributaries, Bangladesh's alluvial soil is highly fertile, but vulnerable to flood and drought. Hills rise above the plain only in the Chittagong Hill Tracts in the far southeast and the Sylhet division in the northeast. Straddling the Tropic of Cancer, Bangladesh has a tropical monsoon climate characterized by heavy seasonal rainfall, high temperatures, and high humidity. Natural disasters, such as floods, tornadoes, and tidal bores affect the country yearly. Bangladesh also is affected by major cyclones, on average 16 times a decade.
Climate of Bangladesh:
Straddling the Tropic of Cancer, Bangladeshi climate is tropical with a mild winter from October to March, and a hot, humid summer from March to June. The country has never frozen at any point on the ground. A warm and humid monsoon season lasts from June to October and supplies most of the country's rainfall. Natural calamities, such as floods, tropical cyclones, tornadoes, and tidal bores occur almost every year, combined with the effects of deforestation, soil degradation and erosion.
In September 1998, Bangladesh saw the most severe flooding in modern world history. Two-thirds of the country was underwater. There were several reasons for the severity of the flooding. Firstly, there were unusually high monsoon rains. Secondly, the Himalayas shed off an equally unusually high amount of melt water that year. Thirdly, trees that usually would have intercepted rain water had been cut down for firewood or to make space for animals.
Bangladesh is now widely recognized to be one of the countries, most vulnerable to climate change. Natural hazards that come from increased rainfall, rising sea levels, and tropical cyclones are expected to increase as climate changes, each seriously affecting agriculture, water and food security, human health and shelter. It is believed that in the coming decades the rising sea level alone will create more than 20 million climate refugees. Bangladeshi water is contaminated with arsenic frequently because of the high arsenic contents in the soil. Up to 77 million people are exposed to toxic arsenic from drinking water. Bangladesh is among the countries most prone to natural floods, tornados and cyclones. Also, there is evidence that earthquakes pose a threat to the country. Evidence shows that tectonics have caused rivers to shift course suddenly and dramatically. It has been shown that rainy-season flooding in Bangladesh, on the world’s largest river delta, can push the underlying crust down by as much as 6 centimetres, and possibly perturb faults.