Europe baked under a 'heat dome' on Wednesday as temperatures neared 40C and a deadly heatwave tightened its grip across the continent.France recorded its hottest-ever day for the second day running, with temperatures topping 40C in more than 50 departments since the latest heatwave began on June 17.'It's difficult to live alone and without air conditioning,' said 62-year-old retiree Martine Belloc in Bordeaux. 'We're suffocating in the streets,' a tourist in Paris added.The extreme weather is being driven by a persistent pattern that traps hot air over the region for days, allowing temperatures to keep rising. Scientists say such events are being intensified by global warming.France's national temperature indicator - an average of daytime and nighttime temperatures across 30 stations - reached 30C on Wednesday, the hottest since measurements began in 1947.It broke the previous day's record of 29.8C. This week's heat has already claimed lives, including two brothers aged two and four who died in a family car in the French town of Carpentras on Monday. The Carpentras prosecutor's office said, that according to the initial autopsy results, the children died 'from exposure to excessive heat... subject to the results of further analyses currently underway'.The children's mother has been charged with involuntary manslaughter after giving conflicting versions of events to police about how they became locked in the car. The French weather agency put three-quarters of the country under a red alert for extreme heat starting at midday Thursday until the same time Friday.