People have been living in those cold climates long, LONG, before modern heating systems. More than "laziness and disliking hot summers" I would say that humans

People have been living in those cold climates long, LONG, before modern heating systems. More than "laziness and disliking hot summers" I would say that humans will settle wherever are resources that can support them, period. An example: http://en.wikipedia.org/wiki/Sami_people http://en.wikipedia.org/wiki/Sami_people