Sea-Level Changes Along Bangladesh Coast: How Much Do We Know About It?

Abstract

AbstractBangladesh is considered to be one of worst victims due to climate change-induced sea-level rise, which would force millions of people to leave their homesteads and become climate victims. However, based on limited and poor quality information, it is very difficult to make such a straightforward statement, without knowing the critical and complex local situation of the coast. The quantity and quality of data are not adequate enough to make any precise conclusion about the rate of sea-level changes in the past, present, and future. However, in this chapter, it has been attempted to make a critical overview of the existing knowledge to depict the sea-level scenarios along the coastal belt of Bangladesh. It shows that during the Holocene period sea level was oscillating with an average rising rate of 1.75 mm/year, and shows at least five transgressive–regressive episodes. Based on tidal records and satellite altimeters, the assessment of current trends of sea-level rise made by different authors are not in agreement and varies from 2.1 to 25 mm/year (mostly around 8 mm/year). The projection by year 2100 is also dubious, which varies from 0.85 to 4.5 m (mostly around 1.4 m). This synthesis shows that in addition to climate changed induced global contributions, the major components for sea-level movements of Bangladesh are regionally and locally driven. Reduction of sediment supply from upstream and stoppage of regular sediment influxes to the coastal floodplain in the downstream are major anthropogenic causes to increase the sea-level height along the coastal belt. Practically, what we currently observe in the coastal belt is not the secular sea-level rise; rather, it is the amplified local tide-level rise, which is mostly related to humanly induced non-climatic factors.KeywordsClimate changeSea-level riseAnthropogenic processesBangladesh coast