Bangladesh is already in trouble due to rising seas.
A common enough misconception (due to what the media tend to illustrate stories about rising seas with) . Bangla Desh is very flat, but its rising out of the ocean. It's regularly flooded by rivers, not the sea. The upside of which is that it's about the most fertile piece of property on the planet.
Geological rise is over the period of Millenia. Since we're melting the ice caps much faster than say 100,000 years...
I'm not talking about geological rise. The whole state is built on silt deposits, and there's A LOT of it coming down those rivers every year.
Presumably with each bad flood, Bangladesh rises up a little bit more.
That would make a pretty good patriotic one liner for a Bangladeshi politician