The waters of the Euphrates River gave birth to civilization and are just as valuable today — but they are also in short supply, as people in Syria, Turkey, and Iraq battle for a share of the river. Similar struggles are taking place all over the world, from Texas to China, as water resources grow scarce and competition for them mushrooms. Less than 1 percent of the world’s water supply is suitable for drinking or agriculture, and demand for it is has increased six-fold over the last 70 years; meanwhile, the supply itself might be shrinking due to the erratic weather patterns caused by global warming. Researchers estimate that by 2015, at least 40 percent of the world’s population will live in countries where it is difficult or impossible to satisfy basic water needs. According to the World Bank, dwindling water supplies will inhibit economic growth, and the U.N. and a Central Intelligence Agency advisory group predict that competition for water will lead to an increasing number of conflicts worldwide.