It was just a matter of time before Eugenics met Climate Change. Even if it sounds like science fiction and absurd speculation, the discussion is taking place now in scientific circles.
In fact, this is the ultimate application of science to the human condition. For instance, designer babies might be genetically engineered to be smaller as adults: This would proportionally reduce their carbon footprint.
Or genes might be inserted to improve night vision. That would allow nighttime lighting requirements to be reduced, thus saving boatloads of energy and reducing carbon.