A blistering and unseasonable heatwave has struck southern Spain, Portugal and Morocco this week, with temperatures approaching 40°C in some regions. The hot weather has heaped further climatic stress on southern Europe, which is already under a severe drought that is
. Here’s what we know about why the record-breaking heat is occurring, and how it could be linked to climate change.On 27 April, Spain recorded its hottest-ever April temperature at Cordoba airport in southern Spain, which reached 38.8°C according to the Spanish meteorological service. This smashed the previous record of 37.4°C, set in April 2011 in Murcia.
Portugal also recorded its highest ever April temperature of 36.9°C at Mora, in the centre of the country. Meanwhile in Marrakech, Morocco, temperatures reached a record 41.3°C.These temperatures are 10-15°C above the seasonal average, according to the UK Met Office.The heatwave is being driven by a mass of very hot air travelling from Africa into Europe, coupled with a slow-moving high pressure system that is suppressing rainfall and keeping skies clear, allowing heat to build.
The ongoing drought is likely also playing a part. Moist soils provide a cooling effect as the water they contain evaporates. If soils are dry, little of the sun’s energy is used for evaporation and transpiration, leaving more solar radiation to accumulate as surface warming.Get a dose of climate optimism delivered straight to your inbox every month.at ETH Zurich in Switzerland says dry soils can increase the severity of a heatwave by 2-3°C.