In today's interconnected world, regional droughts can have a global impact on food supplies and undermine the economics and stability of governments.

For example, droughts last year in Russia and Ukraine reduced the wheat harvest by 32.7% and 19.3%, respectively, severely diminishing the worldwide wheat supply. China, the world's largest wheat producer and consumer, is being forced to import grain after a continuing drought in its northern growing region (Nature 470, 307; 2011).

The fall in wheat production has contributed to a sharp rise in global prices — by February 2011, these had more than doubled in 8 months. The economies of wheat-importing countries in the Middle East and North Africa are particularly hard hit. This is especially true of Egypt, the world's largest wheat importer, and Tunisia and Libya, where the steep rise in the cost of food is fuelling political and economic dissatisfaction.