Becoming Human

I was watching the first part of the Nova series on Becoming human on PBS tonight. They were saying that for several million years human ancestors brain capacity of adults was about 400 cc. However, the next 2 million years after that there was extreme climate change in Africa where early human types were evolving. During extreme climate change the brain capacity doubled in these early humans to about 700cc and most of the other early human types that weren't as smart died off(went extinct) because they couldn't survive the extreme climate changes.

Likewise the extreme climate changes that the earth is entering into will likely increase again the brain capacity of the groups of humans who actually survive the coming extreme climate changes of the next several thousand years or more. So it is possible out the other end of the next series of extreme climate changes here on earth human brain capacity could eventually double again.