Changing extreme sea levels in the Ganges-Brahmaputra-Meghna delta

Low-standing deltas are a home for half a billion of people that are extremely vulnerable to sea level variations. Justly only in the Ganges-Brahmaputra-Meghna (GBM) delta, over 100 million people suffer every year from floods due to storm surges and monsoons exacerbated by the ongoing sea level rise. The aim of our study is to re-assess the variations of extreme sea levels (ESL), as well as the interactions between the relative sea level rise and the ESL in the GBM delta. A set of hourly tide gauge records from the Bay of Bengal, especially from the low-lying Bangladesh's coastal area, has been used to evaluate ESL changes over the past decades. We focus on the variations of extreme high waters and their components (surge and tide), and on the interaction between them by applying advanced methods of statistical extreme values analysis. An assessment of temporal changes in storm surge duration and their intensity was obtained in the framework of a rigorous re-analysis of the past storm surge events.