Tropical cyclone risk in Bangladesh

Abstract

We explore current and future tropical cyclone risk in Bangladesh using numerically simulated tropical cyclones downscaled from reanalyses and from current and future climate states simulated by five CMIP5 and seven CMIP6 climate models. The downscaled tropical cyclones provided statistically robust estimates of wind and rain risk and how these risks may evolve over this century if little is done to curb greenhouse gas emissions. While there is considerable scatter among the climate models used, the multi-model consensus suggests that the probability of coastal winds exceeding 100 kts will triple, while those in excess of 150 kts will increase by a factor of ten by the end of the century. Likewise, the frequency of storm total rainfall at Dhaka in excess of 500 mm increases from once in 325 years to once in 40 years by the end of the century, while the probability of rainfall in excess of 1 meter increases by a factor of about 20. These results indicate very substantial increases in risks associated with tropical cyclones in Bangladesh over the next 80 years, barring substantial reductions in the accumulation of greenhouse gases in the atmosphere.