Government ministers and experts will be gathering in The Hague at Second World Water Forum this weekend to try to avoid it. The BBC's Paul Welsh assesses the risks. In the first of a three part series, he travels to Israel.
Fishermen haul in their nets on the Sea of Galilee.
Things seem to have changed little from biblical times, but they have. I can promise that if there is not sufficient water in our region, if there is scarcity of water, if people remain thirsty for water, then we shall doubtless face war. These waters are a source of great tension between countries, not because they are holy, but because they are scarce. Yitzhak Gal from the Lake Authority showed me how the waters have fallen to a critically low level. Today you can see the lake is lower and the shoreline is in the far.