Global warming is accelerating the problems, the report warns. The 1990s were the warmest decade since measurement began in the 1860s. Scientists believe that higher temperatures will lead to decreased water supplies as deserts expand and evaporation rates increase. Rivers will dry up as droughts intensify. The melting of the polar ice caps will increase the amount of water in oceans and lead to the intrusion of salt into freshwater bodies.
Shortages can lead to conflicts, the report says.