In the last 12 months an estimated 350,000 cattle have died in Chihuahua, the largest of Mexico's 32 states, due to the worst drought on record. No rain means no pasture and local ranchers are desperate. So are the farmers. In 2011, Chihuahua's corn harvest, which normally totals around 100,000 metric tons, yielded just 500 metric tons. Meanwhile, local aquifers are at their lowest levels ever, and falling by several feet a year. In some areas, without hydrological studies, communities have no idea how much longer the aquifers will last. As they wait anxiously for rain, one of Latin America's leading climate change scientists, Dr Carlos Gay, of Mexico City's UNAM university, has warned that the region's climate may have already changed.