This is worth a read:

https://www.scientificamerican.com/article/scientists-can-no...

“ Using a climate model, the researchers compared simulations accounting for climate change with scenarios in which human-caused global warming did not exist. They found that the influence of climate change roughly doubled the risk of an individual heat wave. The key to the breakthrough was framing the question in the right way—not asking whether climate change "caused" the event, but how much it might have affected the risk of it occurring at all.”