The danger being talked about the danger areas of the coasts of Gujarat, Sindh, entire Bengal region, Kerala and some part of the eastern coast (Orissa, Andhra and Tamil Nadu). Note from the picture how Bangladesh and West Bengal are almost at sea level. Bangladesh is considered a particularly vulnerable region as it is a low lying region, with a high population density, and consisting of mostly poor people heavily dependent on agriculture.
Most likely scenario:
Sea Level Rise could become a cause for successive out-migration. Yu et al. (2010) looked at several scenarios for SLR and concluded that in a 4°C world, a rise in sea level of 62 cm by the 2080s could result in a loss of 13% of Bangladesh’s coastal land area to the sea and lead to flooding of 20% more land than currently. A 15 cm sea level rise by 2030 would lead to 3% of land loss and 6% of total flooded area increase; a 27 cm SLR would cause 6% of land loss and 10% of flooded area increase in the 2050s. This will, most likely, lead to the displacement of many people.
A Region at Risk: The Human Dimensions of Climate Change in Asia and the Pacific
SLR will increase flooding in Bangladesh, make the surrounding land saline and unfit for cultivation, and have major socio-economic impact on Bangladesh and in turn India.
Increased rainfall and increased SLR, associated with the effect of climate change, are the two factors that would induce the flooding in Bangladesh. Intensified monsoon rainfall would increase the flood discharge in the river system. In addition, SLR would increase the extent of tidal flooding after its propagation. Both of these climate change–induced factors would ultimately result in an increase of flooded area and inundation depth. The digital elevation data of Bangladesh indicates that more than 50% of the area is less than 5 m above mean sea level. Therefore, a 1-cm SLR would have socioeconomic consequences for the country.
Evolution of the Bengal Delta and Its Prevailing Processes
Why is the Bengal region so low lying?
There is a geological reason for this. Millions of years ago, the northeast part of the Indo-Australian plate fractured and collapsed beneath the sea. This depression in the plates attracted the rivers of the region to drain into it. Along with the water, the rivers also carried massive amounts of sediments, which after depositing over millions of years formed the present Bengal Basin and also the ongoing delta formation.
The sediments increased the fertility of the land and that is one of the reasons the region is home to 2% of the world’s population. Having a large number of people living on land that is almost sea level is not a good idea.
Why The Sea Level is rising?
Sea level rise isn’t only due to the increase in the volume of water in the oceans. The sea water is warmer due to global warming, this as we all know, causes water to expand. About half of the sea-level rise over the past 25 years is attributable to warmer oceans simply occupying more space.
Polar ice caps are melting, increasing the volume of water in the oceans.
The polar ice caps due to its massive mass consisting of ice, exerts a gravitational pull on the water near it, reducing the overall sea levels. With a less mass of ice, the gravitational pull wanes and it releases water hence increasing sea levels.