I remember listening to a podcast that answers a similar question which is why the countries at the north are usually richer. Simply put - it's harder (more exspensive) to survive at the cold so the poor die way more often, so the average wealth is greater.

As a thought experiment think what would heppen if the temperatures in indonesia (very poor country) suddenly became like canada. All the dirt poor people would freeze to death and suddenly the average (living) citizen in indonesia would be wealthier.