Copernicus, the EU's climate monitor, said on Friday that a record 52 percent of Europe experienced "very strong" heat stress (conditions feeling hotter than 38C) during a summer that was the continent's third warmest on record and its hottest for western Europe. Four of Europe's ten most severe heatwaves occurred this year, alongside the lowest river flows since records began in 1992, which disrupted freight, irrigation, nuclear cooling and hydropower. Scientists say climate change is making heat stress more widespread and persistent in the world's fastest-warming continent, where heatwaves caused tens of thousands of excess deaths.