Of the major ports in India, Diamond Harbour in West Bengal located at the mouth of river Hooghly has recorded the maximum sea level increase, according to data tabled in the Lok Sabha by the Ministry of Earth Sciences.

While recent studies reveal that sea level rise in the country has been estimated to be 1.3 mm/year along India’s coasts during the last 40-50 years, at Diamond Harbour the rise was almost five times higher at 5.16 mm per year. The mean sea level rise for Diamond Harbour was based on recordings over the period from 1948 to 2005. This is followed by Kandla port in Gujarat where the sea level rise was 3.18 (1950 to 2005) , followed by Haldia in West Bengal, which recorded a sea level rise of 2.89 mm a year (1972 to 2005). Port Blair also recorded a sea level rise of 2.20 mm per year (1916-1964).

Sea level rise is said be linked with global warming and as per the fifth assessment report of the International Panel on Climate Change, the global sea level was rising at an average rate of 1.8 mm per year over the last century. Going by the data from the Ministry of Earth Sciences, four ports — Diamond Harbour, Kandla, Haldia and Port Blair — recorded a higher sea level rise than the global average. Chennai and Mumbai, recorded a sea level rise far below the global and the national averages at 0.33 mm per year (1916-2005) and 0.74 mm (1878-2005) respectively.

“Rising sea levels can exacerbate the impacts of coastal hazards such as storm surge, tsunami, coastal floods, high waves and coastal erosion in the low lying coastal areas in addition to causing gradual loss of coastal land to sea,” the Ministry said in response to a question by MPs Saugata Roy and Anto Antony.

The sea level rise is higher in West Bengal, particularly in the Sunderbans delta is because of the deltaic sediment deposition as a result of the mixing of fresh water and saline water, according to experts.

In response to another question related to global warming by Lok Sabha MPs Shivkumar C. Udasi and Kanakmal Katara, the Ministry of Earth Sciences explained that global warming not only causes melting of ice and glaciers, but also leads to internal expansion of water in oceans and thus a rise in the sea level. On results of studies on the impact of global warning, the ministry said heavy rainfall and temperature extremes like heat waves and shifts in semi-arid regions were some of the recent findings which may have linkages with climate change and global warming.

“Studies over Indian region have shown a warming trend of 0.6°C on all India average basis, mainly contributed by maximum temperatures, the ministry said.

Source: The Hindu