Right, that's why the pyramids were build during a cold snap. And we know how much more developed Norther Europe was during the classical age than Greece, Persia, Egypt, etc. And this is also why Russia has always been one of the most developed and wealthiest countries in the world. And why Hokkaido is the wealthiest part of Japan. Etc.

Or maybe even a pile of anecdotes, like most of the developed world happens to be in the north today, does not actually mean anything.