You are near your Ph.D. degree in Environmental Science and having second thoughts now ?? There are enough jobs that starts well above 40 grand for your qualification in consultancies and industries man. It is a demanded job in this time as well. And i am sure even if you join a faculty starting salary is atleast 70 grand.  I think you are starting to get worried way ahead of time, do more research. You should be proud of yourself to have done an indepth study in the field of Environmental Science, and should be an advocate of clean energy, rather than trying to back away from the good stuff you are already in. Good Luck.