Here in London we’re bracing ourselves for what could be a couple of the hottest days on record, with daytime temperatures forecast to hit 40C. Of course, these are levels that many other parts of the world are used to dealing with amid the climate emergency. And sustained hot spells have been more common across northern Europe in recent years.

So, commuters are again being encouraged to work from home, avoiding steaming underground rail lines, and schoolchildren are being given the chance to do half-days in the classroom. But what of the night? In a region where houses are built for cooler weather and few have air conditioning, a common refrain is: “How are you sleeping in the heat?”

Those of you in warmer climes might warn to send us some tips, because it seems the northern European nighttime temperatures have risen faster than those in daytime. Why? Stephen Burt, of the University of Reading, explains.