Scientists say hot spell is worst ever, with nearly half of region’s 850 largest cities facing unprecedented heat stress The number of deaths in France linked to the heatwave has climbed to four toddlers and more than 55 drownings, as the brutally hot conditions sweeping Europe were forecast to shift east, choking 150 million people under 35C (95F) temperatures. Scientists said the heatwave was the most severe and widespread ever, leaving nearly half of the region’s 850 largest cities grappling with unprecedented heat stress. They said the extreme temperatures had been made possible by the climate crisis driven by fossil fuel burning.