Slight hyperbole, but nuclear reactors in Switzerland and France shut down more and more often because the water needed to cool them down is already too hot:
https://www.swissinfo.ch/eng/climate-adaptation/beznau-nucle...
It is far from boiling, but these limits are there to avoid killing all life in the rivers.
> It is far from boiling, but these limits are there to avoid killing all life in the rivers.
Note though that those limits exist just like the emission limits for WiFi: it was a sane number when it was decided. It's not clear at all that raising the temperature a little more will "kill all life in the rivers". It would probably deserve some research.
I think it would be more accurate to say "avoid killing the most vulnerable life" crossing the line would not be the end of the world.