Extreme heat is less spectacularly violent than an earthquake or hurricane, but from 2015 to 2019 it killed more people than any other weather hazard. Last month’s blistering heat waves in the US Pacific Northwest and Western Canada left hundreds of people dead, as these normally temperate regions grappled with record-breaking temperatures. With just over 100 days to go until the COP26 United Nations Climate Change Conference, these incidents are a tragic reminder that adapting to an increasingly hostile climate is as urgent as ever.