Vulnerability of Bangladesh to Climate Change and Sea Level Rise through Tropical Cyclones and Storm Surges

Abstract

Bangladesh is frequently visited by natural disasters such as tropical cyclones, storm surges, floods, droughts, tornadoes, and “norwesters.” Of these, tropical cyclones originating in the Bay of Bengal and associated storm surges are the most disastrous. There are various reasons for the disastrous effects of cyclones and storm surges in Bangladesh. Superimposed on these disastrous effects, climate change and any consequent sea level rise are likely to add fuel to the fire. Arise in temperature is likely to change cyclone activity: cyclone intensity, if not cyclone frequency, may increase. As a result, storm surges may also increase substantially. Sea level rise, an increase in cyclone intensity, and consequent increases in storm surge heights will have disastrous effects on a deltaic country like Bangladesh, which is not much above the mean sea level. This paper examines the climatology of cyclones in the Bay of Bengal for the last 110 years and trends in cyclone frequency and intensity. The phenomenon of storm surges in the Bay of Bengal is examined along with the primary reasons for the severity of storm surges in Bangladesh. The paper discusses both qualitatively and quantitatively the impacts of rises in temperature on tropical cyclone intensity in Bangladesh. With the use of a mathematical model developed for the simulation of storm surges along the Bangladesh coast; various scenarios of storm surges are developed. Using lower and upper bounds of sea surface temperature rise of 2 and 4°C and of sea level rise of 0.3 and 1.0 m (according to the Intergovernmental Panel on Climate Change standard), the model simulates the maximum possible surges that are likely to occur under these conditions.