" Harsh conditions await those who are forced to move to the slums
"Climate refugees is a term we are going to hear much more of in the future," observes Saleem-ul Huq, a fellow at the London-based International Institute of Environment and Development (IIED).
He says many Bangladeshi families escaping floods and droughts have already slipped over the Indian border to swell the shanty towns of Delhi, Bombay and Calcutta.
"The problem is hidden at the moment but it will inevitably come to the fore as climate change forces more and more people out of their homes.
"There will be a high economic cost - and countries that have to bear that cost are likely to be demanding compensation from rich nations for a problem they have not themselves caused," Mr Huq predicts. "