I had an idea for an interesting story setup just now. It’s not a story setting I’m likely to use in the near future, but it was fun to think about.
If the world were substantially hotter, it would only be habitable at the poles. It leads to some cool scenarios when people are finally able to get to the other pole. Naturally, it would be more interesting if there were people there already, but how did those people get there? Are there entirely separate evolutionary branches going on, and if so, how do the results compare?
I’m not sure whether a habitable planet that is that much hotter would need more of its surface covered with water or less. Maybe it doesn’t matter.
Other questions arise, like:
Cosmology: would cultures that develop in polar regions have the same misconceptions that Earth civilizations did? Would seeing the sun go around in circles rather than rising and setting alter the perception of the solar system?
Cosmology 2: What shape would such people imagine the Earth to be? Perhaps an inverted bowl, which continues to bulge outward until you reach the edge? Maybe the bowl is spinning on some sort of flat surface beneath, which would explain the seasonal motion of the sun.
Mythology: The sun is important, but too much sun is deadly. Would a culture whose boundaries are defined by the strength of the sun imagine that evil lurks in the shadows they way we do, or are the shadows where the good guys take refuge from the evil that inhabits the sunny regions?
Navigation: It doesn’t seem to me that anyone will be inventing a compass in those parts. When travelers venture far to the south, what troubles are they going to encounter when trying to find their way around?
Weather: I bet there would be days when the huge storms come from the south (for the north pole dwellers) fed by the extra energy from the sun.