I thought it was because you're basically getting a double dose of sunlight when you're hanging out in the snow all the time, since the sun reflects back off the snow.
Which is definitely a real issue, but I guess it might not be why they're darker skinned.
It's more that darker skin was never selected against, so if the people settling the area had dark skin to begin with then if there was no pressure to lose it, they would not. If their diet supplied vitamin D, then there's no reason people with darker skin would be selected against.
I thought it was because you're basically getting a double dose of sunlight when you're hanging out in the snow all the time, since the sun reflects back off the snow.
Which is definitely a real issue, but I guess it might not be why they're darker skinned.
It's more that darker skin was never selected against, so if the people settling the area had dark skin to begin with then if there was no pressure to lose it, they would not. If their diet supplied vitamin D, then there's no reason people with darker skin would be selected against.