New Moore Island in the Sunderbans has been completely submerged, said oceanographer Sugata Hazra, a professor at Jadavpur University in Calcutta. Its disappearance has been confirmed by satellite imagery and sea patrols, he said.
"What these two countries could not achieve from years of talking, has been resolved by global warming," said Hazra.
Scientists at the School of Oceanographic Studies at the university have noted an alarming increase in the rate at which sea levels have risen over the past decade in the Bay of Bengal.
Until 2000, the sea levels rose about 3 millimeters (0.12 inches) a year, but over the last decade they have been rising about 5 millimeters (0.2 inches) annually, he said.
Another nearby island, Lohachara, was submerged in 1996, forcing its inhabitants to move to the mainland, while almost half the land of Ghoramara island was underwater, he said. At least 10 other islands in the area were at risk as well, Hazra said.
The disappearance of the island is consistent with recent data and projections, which have implications far beyond the scope of geography and population of the town where I was raised.
(Sugata Hazra, the head of oceanography at Kolkata's Jadavpur University), said sea-level rise, changes in monsoonal rain patterns which altered river flows and land subsidence were all contributing to the inundation of land in the northern Bay of Bengal.
The low-lying delta region that makes up much of Bangladesh and the neighbouring Indian state of West Bengal are acutely vulnerable to climate change.
The United Nations Intergovernmental Panel on Climate Change predicts rising sea levels will devour 17 per cent of Bangladesh by 2050, displacing at least 20 million people. More than 155 million people live in the country.
The Bangladesh non-governmental organisation Coastal Watch says an average of 11 Bangladeshis are losing their homes to rising waters every hour.
Professor Hazra predicts that 15 per cent of the Indian Sundarbans region on the northern shore of the Bay of Bengal will be submerged by 2020.