A pioneering new study by University of California scientists says the arid Middle East is rapidly getting drier.
They say groundwater depletion in the Tigris-Euphrates-Western Iran region is happening much faster than people expected.
Depletion is quickened by farmers who pump water from limited underground aquifers to feed crops.
These aquifers will not be replenished, and groundwater depletion is worsening all over the world - especially in the arid and semi-arid parts of the globe.
Unsustainable loss of a vital resource like water could lead to disputes between countries in the region without an international plan for water policy and sharing.
Al Jazeera's Rob Reynolds reports from Los Angeles.