River deltas are ideal sites for human habitation because of their fertile floodplains, easy
access to the ocean, and abundant land. But anthropogenic and natural processes are
causing deltas to sink, which increases the probability of coastal flooding and human
exposure to risk. The full extent of the risk posed to humans is unclear because the number
of people living on river deltas is unknown. Towards this end we mapped the locations and
areas of all deltas in the world (n= 1813). Using Google Earth we identified all river mouths …