India is losing land in the Sundarbans. Recent satellite analysis by the Indian Space Research Organisation shows that 3.71% of the mangrove and other forests in the area have disappeared along with 9,990 hectares of landmass to erosion in the past decade.

The forest in West Bengal, which is contiguous with the Bangladesh Sundarbans, is an immensely fragile ecosystem and one of the biggest threats to it is climate-change driven sea level rise. But the small islands on the fringe of the Sundarbans have been shifting, shrinking and disappearing, leaving a trail of climate refugees for more than 40 years and from other human interventions.

Ghoramara island

Tuhin Ghosh of the School of Oceanographic Studies at Jadavpur University has been studying changes to the tiny islands that dot the mouth of the Hugli river. In a study published last year, Ghosh and his co-researchers found that between 1975 and 1990, islands like the Lohachara and Bedford Islands disappeared from their original location. Another small landmass, Ghoramara island, provides the most telling case of vanishing land and displaced people. Satellite images show that in 1975 Ghoramara had a total area of 8.51 s km, which shrunk to just 4.43 sq km in 2012. "Everywhere there is sharp cutting of the river banks, chunks of mainland are being diplaced from the mainland and getting submerged," Ghosh said.

With thousands being pushed off the islands its population growth dropped to 0.55% per year while the overall growth of the admnistrative block in which it is located is about 2.1%. Neighbouring Sagar Island took in the refugees from the vanishing islands and at least five Ghoramara villages with the result that its population growth outpaced the expected trend between the years 1981 and 1991.

Figure: Island Erosion and Afflicted Population: Crisis and Policies to Handle Climate Change (T. Ghosh, R. Hajra, A. Mukhopadhyay)

The question of how many people have been displaced from Ghoramara is a tough one because there have been no actual government records but most people in the area are of the opinion that some 4,000 people have left. The island residents faced with their disappearing lands and livelihoods depend on faith in the local gods, since there is no official policy for adapting to the changes.
Ghoramara and its neighbouring submerged islands  are about 20 kilometeres up the river. The loss of their landmass is not driven just by rising sea levels whose most drastic effects would have been seen lower downstream. Instead, said Ghosh, the engineering interventions to revive Haldia port in the 1980s and the resulting water diversion may be playing out here. "There may be some effect of sea level rise but there is more of an impact from the change of the river hydrodynamic condition created by the guidewall," Ghosh said.

A case has been filed in the National Green Tribunal about human interventions in the Sundarbans, like illegal construction of buildings and infrastructure. The ISRO study  showing a loss of almost 10,000 hectares of land in the past decade came out of an NGT order for a satellite analysis of the area to determine violations. "There is unauthorised construction, there are illegal encroachments of brick kilns and shrimp farming," said Subhash Datta, amicus curae in the case. " If we can't arrest these things then the pressure on the land will become even more adverse."