Thinking about this raised a question; if it's always winter in one hemisphere, is it always summer in the other? If so, this pairing is basically just asking which hemisphere to doom with eternal winter - "yours" or "theirs".

To me the question is more interesting on a philosophical level, and its more about what you gain than what you give up. That is, would you rather give up winter (always summer) or give up summer (always winter. For some giving up winter is obvious, but others really like winter. But do they like it as much as summer?

I said that backwards it should have been "more about what you give up than what you gain"

Eternal summer wouldn't work either. Most plants and animals require fall, winter and spring to thrive. Humanity couldn't adapt quickly enough.

One final summer for mankind.