alt Hacker News> 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.
No, it isn't a made-up number. We know pretty well when do fishes die en masse, as we have seen it in periods of extreme heat before. The research has been done and is how the limits have been defined.