If climate change does lead to a 3-foot rise in sea levels around Bangladesh by mid-century, as some scientists predict, then Shelim's story could echo those of 20 million climate change refugees here. It's an aspect of global warming that's only now being more fully appreciated, but which Atiq Rahman, the country's leading environmentalist, calls one of the biggest threats facing not only Bangladesh, but the world.
"There will be global destabilization of populations," he told me. "The poor will be the most affected. They'll have very little to lose once they've lost their land."
Rahman heads the Bangladeshi Center for Advanced Studies and was also an author of the U.N.'s Intergovernmental Panel on Climate Change reports.
In Dhaka, the impact is already being felt, with some half a million migrants arriving in the city each year. That's about the population of Washington, D.C., pouring mostly into squalid slums. The biggest reason for moving is environmental degradation.
"People are moving, being displaced forcibly, because of climate factors," according to Rabab Fatima, the Dhaka-based representative of the International Organization for Migration.
The crowded and gridlocked capital, home to at least 12 million people (probably more, but nobody knows for sure) is already under stress because of the explosive rise in population. The number of people living in Bangladesh’s capital has doubled in a decade.
"Bangladesh is the most vulnerable country in the world, the frontline state of climate change," Rahman said, pointing to a large map on his wall, a thick black line across the delta, cutting off a fifth of the county. "Anything south of this line is going to under water."
More than half of Bangladesh is less than 20 feet above sea level. Experts say it faces a double threat: Rrising sea levels as a result of the melting ice caps and glaciers, and more extreme weather, like cyclones and heavy rain.
Taken together this could generate more climate change refugees than anywhere else on earth.