Up to 20 million people in low-lying Bangladesh are at risk from rising sea levels in the coming decades, according to new research.
Scientists predict that salty water could reach far inland, making it hard to cultivate staple foods like rice.
The research comes as the government appeals for $5bn (£3bn) over five years to combat climate change.
In May, Cyclone Aila left thousands homeless, killed many and caused widespread flooding and damage.
The predictions come from the Centre for Environmental and Geographic Information Services (Cegis) in Bangladesh.
It suggests a surprisingly small area of land will be permanently lost to the waters, but notes that vast tracts in the south-west could be inundated every monsoon season.
