The mass casualty heatwave that broiled the Pacific Northwest and western Canada last month is precisely the kind of catastrophe predicted by climate scientists two decades ago, Yale Climate Connections reports. In 2001, the IPCC’s Third Assessment warned the greatest increases in heat stress were expected in “mid- to high-latitude (temperate) cities, especially in populations with non-adapted architecture and limited air conditioning,” the scientists wrote at the time. “A number of U.S. cities would experience, on average, several hundred extra deaths each summer.”

This year’s June heatwave killed nearly 800 people in the usually-temperate region where few live in homes with air conditioning.

That heatwave would have been “virtually impossible” without human-caused climate change. It also shattered residents’ feeling of immunity to the ravages of climate change. “We saw the forecasts and it was hard to believe as we don’t really have heatwaves like that. In Seattle it’s usually so overcast during June we call it Juneuary,” Kristie Ebi, an epidemiologist at the University of Washington, told The Guardian. Ebi said she knew the heatwave was serious when she woke up at 6:00 a.m. and temperatures had already hit 80°F. “You see the heatwaves hit other places and you know it’s bad but there’s not the sense of urgency until it hits you,” she said. (Scientists’ forecast: Yale Climate Connections; PNW air conditioning: The Guardian; Climate Signals background: June 2021 PNW heatwave)