GLOBAL CLIMATE CHANGE AND ITS EFFECT ON HYDRO-GEO-ENVIRONMENT OF BANGLADESH COASTAL BELTS

Bangladesh has about 710 km long complex shoreline. It extends along the Bay of Bengal from the mouth of the Naf River in the southeast to the mouth of Raimongal River in the southwest. The coastal morphology of the country is a very complex and dynamic system undergoing continuous changes as a result of active delta building processes. The sea level rise at any levels, are also another disaster risk in the coastal cities. The tidal flooding during pre-and post Monsoon period with high frequency cyclone and storm surges create another hydro-geo-environmental imbalance in these areas. Several observations on hydro-geo-environmental issues of the coastal areas are considered based on the following points, which are salinity, sedimentation, water logging and drainage congestion, erosion and accretion, subsidence, cyclone, tidal flooding, fisheries, agricultural, deforestation, afforestation, navigation, wetland and biodiversity. One of the major consequences of increased surface air temperature and intense floods is the rise of sea level. During the last 100 years, the sea level has risen by about 10-15 cm. Present day rainfall condition in SW Bangladesh for example, it is increasing from the previous study which ranges from 1.8 to 256.5 mm/a. Observation on the long-term surface temperature (1900-1993) of southwest Bangladesh shows an increasing tendency from the previous study which ranges from 0.29 (Barisal) to 0.77⁰C (Satkhira), Change in water quality and quantity due to climate change are expected to affect food availability, stability, access and utilisation. Bangladesh, one of the world's low-laying countries, is vulnerable to sea-level rise. The population is already severely affected by storm surges. Catastrophic events in the past have caused damage up to 100 km inland. It is hard to imagine to what extent these catastrophes would be with accelerated sea-level rise. Digital terrain modeling techniques have been used to display the Bangladesh scenarios.

The relevant organizations of Bangladesh should be investigated immediately in details, the issue of Climatic Change effects on Bangladesh in the present condition.