>>204124well at 21 i started a degree in environmental sustainability: biodiversity and park management. which is basically environmental science. I literally have alllll of the same interests as you so I know youll love that type of degree too. HOWEVER! i wouldnt suggest it if you want a stable career. only do it if you know youll do extremely well and youre good at networking. the best way to get work in it is to be opportunistic.
I loved it though, especially looking at the biology of evolution and just going into the outdoors all the time. im in Australia and im trying to get into project firefighting which i can then move on into being a fire ranger for the government. its all dont through DEWNR anyway so its like a ticket in.
I would suggest (if you were in australia) something like surveying or geology if you are interested in it. A LOT easier to find work that way