Since you have not said what your degree is in its hard to say. yes I think it would make money but you definitely will need certification that shows you know what you are talking about....
And since you are only 21 you may want to go and work for green consulting firm just to get your feet wet and see if that is how you would want to spend your life. It may be that it is not for you or you may be able to find someone to work for that gives you a lot of room to express your ideas on how you do your job. Good luck
century press