When the temperature hit 40C in Britain last summer, the empty streets appeared “dystopian” to Dr Laurence Wainwright, a sustainability and psychiatry academic at Oxford University. Yet what he had assumed would serve as “a real wake-up call” on the world’s increasingly dangerous temperatures – which resulted in a European heatwave that killed more than 60,000 people last year – failed to prompt action. During the past month or so – as wildfires have torched more than 500 sq km of Greece, Arizona notched up a record-breaking 31 consecutive days at 43C or more and July became the hottest month ever recorded in the modern era – the extreme heat crisis has only appeared to grow. There’s no doubt about it, Wainwright says: “We’re in serious trouble.”
When the human body is exposed to excessive heat, it attempts to maintain its internal temperature by sweating – which cools you down as beads of perspiration evaporate – and by diverting additional blood flow to the skin, which allows for extra heat loss by convection.