Times (UK): The number of sweltering nights when the temperature in cities stays above 20C (68F) and the elderly become vulnerable to heat exhaustion will increase fivefold because of climate change, a Met Office study has found. Opening the windows will make no difference because the outside temperature will be too warm for the heat in homes to escape. The “urban heat island effect’, in which buildings and roads absorb heat during the day and release it at night, could result in the temperature …