Sea level set to rise 2 ft. in Sundarban by 2100

Sundarban, the island territory at the southern fringe of West Bengal, is set to experience about 2 ft sea level rise in between 2015-2100; points out a recently released IPCC report.

The analysis of the interactive map in the report shows that under worst emission increase scenario, the sea surface with rise about 10 cm in near future (2021-2040), about 20 cm during 2040 – 2060 & 60 cm, which is 2 feet, during the last two decades of the current century.

Incidentally, Sundarban is spread over nearly 10,000 sq. km with about 5 million people living in close vicinity to more than hundred royal tigers & unique biodiversity, is already having record sea level rise in the country.

According to a report, placed by Union Ministry of Science and Technology in Indian parliament sometimes back, Sundarban region is presently experiencing about 6 mm sea level rise annually. However, experts also point out that actual impact of sea level rise is higher as Sundarban’s landmass is also settling down at a rate of 4 mm per year.

“In Sundarban, the relative sea level rise, that includes both actual sea level rise and land subsidence, is about 10 mm per year now which is definitely going to increase if the carbon emission is not immediately controlled”, said SugataHazra, a professor in department of oceanography from Jadavpur University , Kolkata , India.

Hazra points out that already islands like Lohachora&Newmoon have completely submerged into water while islands like Ghoramara, Mousuni and Jambudwip are eroding at a sharp rate. Incidentally, Indian Sundarban has more than 100 islands, almost equally divided between human habitation & wild animals; and often, located in close proximity. The area with nearly 5 million populations has limited resilience to combat the climate extremes as a sizeable live in abject poverty.

Experts point out that occurrence of multiple extreme weather events in tandem, as found during cyclone Aila in 2009 and cyclone Yaas in 2021, adds to existing vulnerability of Sundarban area.

In both cases, high intensity cyclones along with intense rainfall and peak of high tides had overlapped; flattening innumerable mud houses as well as livelihood support of millions.

During last two years – November 2019 to December 2021 – Sundarban had to face the wrath of four major cyclones; Bulbul, Amphan, Yaas and recently Jawad.

Incidentally the recent IPCC report, for the first time, has recognised the co-ordinated impact of climate change events; though the earlier IPCC report (AR5) also acknowledged the possible impact of climate changes in Sundarban.

The recent reports shows that under worst possible scenario, Sundarban’s maximum one day rainfall may increase over 46 percent with a possibility of 129 mm rainfall in a day, compared to pre industrial era benchmark. Experts point out that most of the increase will happen during present century.

Though the short burst rainfall is set to rise steeply, the overall rainfall will marginally increase during the ongoing century, about 18 percent, under worst possible scenario.

On temperature front, Sundarbans’s mean temperature will rise 4.1 degree Celsius by 2100 under worst emission scenario, while the mean temperature rise will be almost 2.1 degree Celsius if the global temperature rise can be contained within 2 degree Celsius.

An earlier World Bank study has shown that though the overall number of cyclones around Sundarban has not increased, the high intensity extremely severe or super cyclones are on course for significant increase.

Incidentally cyclone Amphan, which struck Sundarban& adjoining Odisha coast in last May, was the first super cyclone in the history of Bay of Bengal since1999 Odisha cyclone though it turned into an extremely severe cyclone once having the landfall.

“It is expected that there will be more cyclones in Sundarbans in future” pointed out SunandaBandyopadhyay, a professor in Geography in Calcutta University, who was part of the World Bank study.