Drought may be an ancient scourge, but it is getting worse. No region or country today is immune to its effects. Southern Europe is in the grip of a severe drought -- the worst in 70 years for Italy. In the western United States, the past two decades have been the driest in 1,200 years. Chile is in its 13th consecutive year of drought, and Monterrey, Mexico's third-largest city, is now being...