Why do they go North In Frostpunk?

At a glance the setting of Frostpunk makes no sense. If the world was getting colder, why would they ever decide to go into the cold barren north rather than south where it should be warmer? But could there actually be a logical reason for it to be there? Twitter : Twitch : FAIR USE NOTICE This video may contain copyrighted material; the use of which has not been specifically authorized by the copyright owner. We are making such material available for the purposes of criticism, comment, review and news reporting which constitute the ’fair use’ of any such copyrighted material as provided for in section 107 of the US Copyright Law. Not withstanding the provisions of sections 106 and 106A, the fair use of a copyrighted work for purposes such as criticism, comment, review and news reporting is not an infringement of copyright. #frostpunk #science #frostpunk2 #vtuber