Half a billion people live in deltas, but the newly published research suggests many of these areas are set to be inundated by rising seas.
Some of the lowest lying, including the Mekong and Mississippi, are particularly vulnerable.
The paper is published in the journal Nature.
Lead researcher Dr Liviu Giosan, from Woods Hole Oceanographic Institution in Massachusetts, said dams and other river engineering had exacerbated the problem by reducing the amount of sediment rivers could carry.
In an article he said was “a call to action before it’s too late”, Dr Giosan said rivers were losing the fight between land and sea.