Historically, food security was the responsibility of ministries of agriculture but today that has changed: decisions made in ministries of energy may instead have the greatest effect on the food situation. Recent research reporting that a one degree Celsius rise in temperature can reduce grain yields by 10 per cent means that energy policy is now directly affecting crop production. Agriculture is a water-intensive activity and, while public attention has focused on oil depletion, it is aquifer depletion that poses the more serious threat. There are substitutes for oil, but none for water and...