Much of the world is in the grip of a heatwave. Britain is so hot and dry that we have Indonesia-style peat fires raging across our moorlands. Montreal posted its highest temperature ever, with the deaths of 33 people in Quebec attributed to the scorching heat. And if you think that’s hot and dangerous, the town of Quriyat in Oman never went below a frightening 42.6C for a full 24 hours in June, almost certainly a global record. While many people love a bit of sun, extreme heat is deadly. But are these sweltering temperatures just a freak event, or part of an ominous trend we need to prepare for?
Earth’s climate system has always produced occasional extreme weather events, both warm and cold. What is different about now is that extra short-term warmth – from the jet stream being further north than usual – is adding to the long-term trend of rising global temperatures. The warming trend is very clear: the US National Oceanic and Atmospheric Administration shows that all 18 years of the 21st century are among the 19 warmest on record; and 2016 was the warmest year ever recorded. Overall global surface air temperatures have risen by 1C since the industrial revolution. It is therefore no surprise that temperature records are being broken. And we can expect this to become a feature of future summers.