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Can anyone identify this story? This was one of the first science fiction books I ever read, probably ca. 1974. May have been written in the 50's or 60's. I think it was what was marketed then as a "juvenile novel" (today's YA novel), possibly a short Scholastic book marketed to grade school kids.
The idea is that the earth has entered a mini ice age, so a group of people have built an underground city to escape the cold. It is now maybe a generation or two later, and they are poking their heads out to see if the ice age is over and the earth is habitable again. I think there may be controversy about whether it's OK to go out yet. Unfortunately there's not much more I can remember -- I was a little kid then.