Heatwaves are more dangerous in cities

AMERICA HAS been baking this weekend. An estimated 128m people along the East Coast and in the Midwest were affected by excessive-heat warnings on July 20th. This particular heatwave is likely to fade quickly, but such events are becoming more common.The US Global Change Research programme has projected that by mid-century, there may be 20-30 more days each year in most parts of America when maximum temperatures exceed 32°C. It is a similar story elsewhere. Researchers think that a record-breaking heatwave in France earlier this summer was five times more likely than it would have been without global warming. Europe is set to experience another bout of very hot weather this week.