Gizmodo asked a number of scholars how they thought AGW will affect human evolution. Some of the answers were interesting. Biological anthropologist John Hawks wrote:
I’ll be honest — the degree of climate change we are talking about in the next couple of centuries, which is on the order of several degrees Celsius, is by and large going to make the temperate regions of the world more similar in temperature to tropical Africa, where all our ancestors originated. We’re effectively terraforming the world to be more like our origins. The effects on humans are much more social and economic than evolutionary.
To the extent we see evolution, it will be changes in plant and animal species. Some will change the timing of their lives, some will invade new areas where they couldn’t adapt before, and many will become extinct — especially those today locked into small “reserves” that will undergo local climate shifts faster than they can adapt. And of course we will exert our own selection and genetic engineering upon our crops and domesticated animals to suit the changing climate.
Biological anthropologist Chris Stringer wrote:
The pace of change is likely to be too fast and dramatic for us to evolve physically to meet the challenges of a much warmer world. Any changes would have to come from cultural or social accommodation to the new situations – if that proves possible.
I think it is still way to early to tell how the earth will respond to anthropogenic changes in climate. If you will recall, only fifteen years ago, people were talking about global cooling.