It's called "displacement"

Ghoramara is a delta island in India, one of thousands of similar islands called the Sundarbans. It sits at the merging of the Ganges river and the Bay of Bengal, and like countless other sea-level chunks of land, it is either sinking or being flooded or both at the same time. Since 1969, Ghoramara has lost half of its acreage to the sea.

On the leading edge of climate change vulnerability, the local government has been taking action by displacing the farming and fishing families whose land is disappearing from beneath their feet. In this NY Times story (registration required), we learn:

Hundreds of families have already been forced into a displaced people’s camp on Sagar, a neighboring island, which itself has shrunk by one and a half square miles in the last five years, according to the Jadavpur University study.

It's not like they've got the displacement process figured out. And so far, we're just talking about the effects of what may be "early" climate change, where sea level rise has been slow, large storms still rare.