I am no expert on this line of work, but from what I know it seems to be centered to large cities and large firms. Also, I think a lot of the litigation takes place in DC. I could be wrong about those points, so I'll defer someone more in the know. But those are things to think about.
Additionally, God bless anyone who wants to do that type of work. I got a BS in Comp Sci and thought along these lines. Patent work may be for some people, but it is not for me. Writing/applying for patents seems mind numbing. I can't imagine litigating the nuances of patents can be that fun either. I took a IP course in law school and knew right away it was not for me.
Environmental work seems like you may be tied into either large firm/large city work or government work. Nothing wrong with these lines of work, just research and know what you are getting into.
Others have probably warned ahead of me and I will warn that you need to think really long and hard about what a law degree is going to cost, what you are going to do with it and whether you would be remotely happy practicing law.
I like practicing law, I don't love it. It is a respectable way to earn a living and there is a high ceiling even for solo practitioners who are willing to get after it.