Across much of the northern hemisphere, intense and prolonged heatwaves have triggered disruption and devastation as North America, the Arctic, northern Europe and Africa have sweltered in record-breaking temperatures. In Africa, a weather station at Ouargla, Algeria, in the Sahara desert, recorded a temperature of 51.3C, the highest reliable temperature ever recorded in Africa. In Japan, where temperatures have reached more than 40C, people were last week urged to take precautions after the death toll reached 30 with thousands more having sought hospital treatment for heat-related conditions. And in California increased use of air conditioning units, switched on to counter...