I thought tha it was the case that some groups of humans did have differences with adaptive significance - in addition to skin colour there is the greater lung capacity of mountain peoples and, I believe, (although this is not directly related to environment as the term is understood in general usage) lactose tolerance.
Also humans, although widespread, have a low genetic diversity compared to most other species so we should not expect too much in the way of differences at this point. The fact that humans have spread as well as they have strongly suggests that technology (in the widest sense of the word) is an adequate substitute for "natural" abilities that might evolve.