Britain experienced its highest temperatures ever recorded in an extreme heat wave last week, as temps rose to over 104°F. Analysis by the World Weather Attribution group — composed of scientists from around the world — found that the same heatwave in a preindustrial world would have been around 10% cooler, making the current British heatwave “extremely unlikely” without human-caused climate change. Heat of last week’s intensity is highly unusual for Britain.

Report authors estimate the chances of seeing the daytime highs recorded in some parts of the country were 1-in-1,000. “It’s still a rare event today,” Friederike Otto, a climate scientist at Imperial College London, and author of the report, told the New York Times. “It’s a worrying finding that suggests that if carbon emissions are not rapidly cut, the consequences of climate change on extreme heat in Europe, which already is extremely deadly, could be even worse than we previously thought.” Hundreds of people are estimated to have died during the scorching heat, though official figures have not yet been released. (Reuters, CNN, USA Today, Sky News, Axios, The Guardian, New Scientist, Washington Post $, New York Times $; Climate Signals background: Extreme heat and heatwaves)