If all the sunshine hitting the Sahara was converted into energy, enough electricity would be produced to power Europe 7,000 times over.But solar panels reflect less heat back into space compared to sand, which could change the region’s climate – and make it rain more. You may have seen a variant of this meme before. A map of North Africa is shown, with a surprisingly small box somewhere in Libya or Algeria shaded in. An area of the Sahara this size, the caption will say, could power the entire world through solar energy. Over the years various different schemes have been proposed for making this idea a reality. Though a company called Desertec caused a splash with some bold ideas a decade ago, it collapsed in 2014 and none of the other proposals to export serious amounts of electricity from the Sahara to Europe and beyond are anywhere close to being realised.