Spring was a scorcher in the Mediterranean. A heatwave in April saw temperatures up to 20°C higher than usual in Algeria, Morocco, Portugal and Spain. Scientists used to hesitate to blame a particular piece of weather on climate change. These days they are more confident. World Weather Attribution, a network of climate modellers, reckons that the heatwave was made around 100 times more likely by the greenhouse gases that are piling up in the atmosphere.