Context

According to Ministry of Earth Sciences, Diamond Harbour, which is one of the major port in West Bengal located at the mouth of river Hooghly, has recorded the maximum sea level increase.

About

More on news:

• 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 this port was based on recordings over the period from 1948 to 2005.

Sea level rise

• It is said be linked with global warming and as per the fifth assessment report of the United Nations International Panel on Climate Change (UNIPCC), the global sea level was rising at an average rate of 8 mm per year over the last century.
• 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.
• According to the data from the Ministry of Earth Sciences, four ports namely 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.
• 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.

Concerns over rising 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.
• If the global warming exceeds 2?C by 2100, about 80 % of global coastline could see a 6-ft rise in sea levels.
• Increase in temperatures due to human-induced global warming can cause melting of ice caps and glaciers which primarily drive increase in sea levels.
• Warming of oceans causes excessive flooding, destructive erosion and agricultural soil contamination in coastal regions. Even the US is facing the heat with Louisiana, the southeastern state, losing 75 sq km of coastal terrain every year.
• Talking about the reason for the nature influencing rise in sea levels centuries ago, ENSO (El Niño / Southern Oscillation) played a big role. ENSO is characterised by changes in sea surface temperatures that influence climatic conditions all over the globe.
• Southeast Asia is one of the most densely populated parts of the world, with a large chunk of people living in low-lying coastal areas. Hence, in future, Southeast Asia could see a magnitude of sea-level rise that far exceeds what has already been projected.

Sinking Chain of Atolls of India Due to constant rising sea level, many small atolls (circular coral colonies) of Indian archipelago are sinking. Parali I Island of Lakshadweep has already sunk and Parali II has sunk almost 80% of its total area. Thinkara (14.38%) and Parali III (11.42%) are eroding at fast pace. UNIPCC in its fifth report has stated that sea level in Lakshadweep has risen up to 0.6 m in last 20 years. This will not only cause loss in livelihood to the native people but also loss of biodiversity as large number of flora and fauna inhibit these Islands along with Particularly Vulnerable Tribal groups (PVTGs). El-Nino event has also weakened coral colonies to a larger extent.