FWIW, I moved from sunny Greece to somewhat cold Austria at the age of (almost) 18. In the following 2 years, I gained quite a bit of body hair (more than typic

FWIW, I moved from sunny Greece to somewhat cold Austria at the age of (almost) 18. In the following 2 years, I gained quite a bit of body hair (more than typical in the family), which I (now) attribute to the cold temperatures I had to endure during the first winters due to poor heating and light clothing. My point is: perhaps the body has more tricks up its sleeve than just to turn up the heating by burning more calories, not all of them as desirable as we'd hope. Then again, it might have been normal for my age and not related to climate, although I had plenty of facial hair very early (at 14) and generally didn't develop/grow much after 16. Needless to say, I wasn't able to reverse the process with proper heating. I lose hair in all the wrong spots only!