It will only get worse as time goes on. The heat we are seeing now has a lag time on the order of decades. So give it another 20 years and it will only get hotter.

I lived in a small city in Wales a few years back.
Pretty much no one had AC in their house/apartment.

A lot of other places didn't either. Like restaurants and pubs.

But the grocery store did. So if it got crazy hot I would sometimes wander around the tesco across the street.

The university I was attending had AC in the newer building but I do believe it wasn't in all buildings.

Train had AC.
The Bus most certainly did not. Riding the bus on a hot rainy day was like being in a sauna. Condensation running down the inside walls and windows. All fogged up windows.

They just aren't prepared to handle this heat.

The windows I had in my apartment were like...they opened like a fridge door on its side. Not slide up like how it is common here in the U.S. Making it difficult to use window AC units.

Plus the additional demand on the power grid for people getting AC for homes and apartments is probably not currently supported.

Managed to keep my indoor temp under 30 today here in Normandy. No AC. Not looking forward to the next few days.

40C is just June through August where I live.

I have a window AC, but most summers I don't bother installing it. I did order a ceiling fan for my bedroom, though. Should be here tomorrow.

You've heard, "but it's a dry heat"? Yeah, that makes a huge difference. It's currently 9% humidity and dropping here.

This is fine.

(/s obv.)

it's not a heatwave, this is global warming. temperatures are this high every summer, and they are this high for the majority of summer.

Heatwaves are going to be when it hits 50 C