In the colder environments it was the smarter people who increased their odds of survival. So culturally a premium was placed on brains as well as brawn. Smarter genes are passed on. In warmer climates where you didn't really have to concern yourself with using your head so much to find food and shelter, it was physical strength and speed that conquered. The strong and aggressive were the ones who passed their genes. So I would assume that it's only natural that certain races have certain genetic predispositions, but again, if you notice, it's still not so much about genes, but it's more about environment/culture. If you take the smarter people out of the aggressive environment and put them into an intellectual environment, they'd have better chances to survive and pass on their genes. But if you take the agressive warrior and put them in a situation that's ruled by cunning, they're not likely to survive. That being said, the US and Canada aren't up there because of race. It's because of culture. Same goes for China.
That's my theory and I don't present it as fact. But I think I'm pretty close to something true here.
I agree with some of your statements, but not so much with your conclusions.
Environmental pressures for adaptations are numerous and their effects are not always obvious, especially when genes are concerned. In any environment (hot, cold, warm), it is the best adapted organism that has the greatest chance of passing on their genes (not necessarily the most intelligent). If you say that cold produces a more intelligent human because it requires more cunning, then I could say that living in the savannah or the jungle requires more cunning. Although there would be more food sources in a savannah or jungle than in a cold, snowy environment, there would also be more diseases, wild animals, poisonous insects and snakes, annual floods etc that one would encounter. They would select for humans that were intelligent enough to use medicine, predict floods, choose edible plants, properly protect themselves from animals, etc. My point is that you cannot say any type of natural environment affects intelligence one way or the other.
I agree with you that upbringing and environment are more reliable and are more accurate determinants of intelligence. However, it cannot be stressed enough that this map ignores several important variables.
Almost all the countries with supposedly low IQs are poor.
Almost all the countries with supposedly low IQs are former colonies.
Almost all the countries with supposedly low IQs have a strong history of exploitation by European states and multinational corporations.
All the countries with supposedly low IQs have a large population of poor people who cannot afford proper nutrition (access to proper food plays a very large role in development and intelligence)
How did they get the data to make that map anyway?