Future sea-level rise projections for tide gauge locations in South Asia

Local projections of future sea-level change are important for understanding climate change risks and informing coastal management decisions. Reliable and relevant coastal risk information is especially important in South Asia, where large populations live in low-lying areas and are at risk from coastal inundation. We present a new set of local sea-level projections for selected tide gauge locations in South Asia. The projections are used to explore the drivers of spatial variations in sea-level change for South Asia over the 21st century under the RCP2.6 and RCP8.5 scenarios. Global sea-level rise for 2081-2100 is projected to be 0.39 m (0.26-0.58 m) and 0.65 m (0.47 m-0.93m) for RCP2.6 and RCP8.5 respectively. Local sea-level rise projections for the same period vary spatially over the South Asia region, with local sea-level rise in excess of projected global sea-level rise in the equatorial Indian Ocean but less than projected global sea-level rise for the northern Arabian Sea and northern Bay of Bengal. Local sea-level rise for 2081-2100 is projected to be 0.44 m (0.29-0.67 m) and 0.72 m (0.51-1.06 m) at Gan II (Maldives) under RCP2.6 and RCP8.5 respectively, whereas for Diamond Harbour (West Bengal) the corresponding changes are 0.32 m (0.19-0.51 m) and 0.57 m (0.39-0.85m). We find that the sterodynamic contribution is generally the leading driver of change at any single location, with future groundwater extraction over the sub-continent landmass the main driver of spatial variations in sea-level across the region. The new localised projections quantify and enhance understanding of future sea-level rise in South Asia, with the potential to feed into decisions for coastal planning by local communities, government, and industry.