Looks like they plugged a number into a template and nobody is proofreading.

Researchers find human-caused climate change raised temperatures by up to 4C, with 1,500 deaths linked directly to it.

It covered 12 cities with a combined population of more than 30 million, including Barcelona, Madrid, London and Milan, where the study said climate change had increased heatwave temperatures by up to 4C (39.2F).

the heatwave “would have been 2-4C (35.6-39.2F) cooler”