As global warming melts the world's ice, and heats the oceans, sea level is rising. It could go up 3 feet by the end of the century. Some coastal areas, such as the low-lying coastline off the Bay of Bengal, where the Ganges, Meghna and Brahmaputra Rivers meet the Indian Ocean, is already threatened.
Just south of Calcutta, India, the Royal Bengal Tiger prowls the Sunderbans Islands, which contains the world's largest unbroken mangrove forest. Some researchers say the rising sea level is making the brackish waters around the southernmost islands too salty, destroying the tigers' habitat, and pushing the animals into nearby villages. There, the number of conflicts with tigers is increasing, risking human life and threatening the future of this rare and majestic animal.
The rising water is also a direct menace to the people of the Sunderbans, many of whom live and work below sea level. Before the Sunderbans were cleared for farming, the tides washed them every day. Then dwellers erected thousands of miles of mud dikes, encircling each island in a protective hug. These earthen embankments require constant vigilance and frequent maintenance, and even the best dikes break up in storms. Tushar Kanjilal, secretary of the Tagore Society for Rural Development, says when they breach, "all the crops are damaged, all the mud houses collapse, all the waters in the ponds, creeks, canals, become saline."
Advancing seas make storm damage more likely and cause land to crumble into the sea. Oceanographer Sugata Hazra, of Jadavapur University predicts India's Sunderbans islands will lose 15% of their area by 2020, displacing up to 100,000 people, who will become "a kind of environmental migrant." He says such climate change refugees will increasingly strain social services and swell India's slums.
Daniel Grossman investigates daily life of farmers, Bengali tigers and birds, all residents of the Sunderbans Islands threatened by a changing climate.