> 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.