Importing Food Means Exporting Drought

If you want proof the world has a water problem you're better treading the damp summer pavements of the City than the parched bed of the Aral Sea.

Goldman Sachs says water is the next oil and has bullish investment trends to prove it. For the rest of us a water boom spells trouble: investors can smell scarcity a mile off and, however much money they pump into managing it, the last result they'll want is abundance.