IN BRIEFMany countries have experienced a succession of record-breaking heatwaves this European summer.They have caused severe droughts, affecting major waterways such as the Danube and the Rhine.Water levels on the Danube River, the second-longest in Europe, have dropped so low because of drought that the hulks of dozens of World War Two German warships are emerging into view.They are a curious distraction from the summer heat crisis. The Danube’s record-low water levels have also pushed power plants to the brink of shutting down, and governments across Central and Eastern Europe are taking steps to conserve electricity.A World War Two German...