Water Scarcity in an Arid Region

North Africa and the Middle East form the most water-scarce macro-region on Earth by most standard measures: the vast majority of countries from Morocco to Iran fall below the widely used Falkenmark threshold of 1,000 cubic meters of renewable freshwater per person per year, the conventional definition of water scarcity, and several Gulf states fall below 500 cubic meters, the threshold for "absolute scarcity." This scarcity stems from the region's predominantly arid and semi-arid climate, low and highly variable rainfall, and heavy reliance on a small number of shared transboundary river systems, chiefly the Nile, the Tigris-Euphrates, and the much smaller Jordan River, whose entire basins lie across contested political boundaries.