Sana’a, Yemen is home to 2 million people and has been around since the 6th century B.C. In 20 years it will be a ghost town. It is drying up. It is drying up because of demand for the mild stimulant Qat. In other words, Sana’a has a drug problem, which means it has a water problem, which means it has an existential problem. Follow the story at Alternet.