Thanks to irrigation, Saudi Arabia has been able to grow its own supply of wheat for more than 20 years. But wheat production is collapsing because the aquifer used for irrigation is almost depleted. Water supplies and grain production are also declining in Syria and Iraq. Wells are starting to go dry in parts of India. China is overpumping water, especially in the North China Plain. About half the world's population lives in countries where the water tables are falling. Saudi Arabia, China and South Korea have been leasing or buying land in other countries, especially Ethiopia and Sudan, to grow grain for their citizens. The potential for conflict between countries over water is very high, says environmentalist Lester Brown (Foreign Policy, May/June).