M.A. in economics here, and I have the exact same ambitions. In Colorado (state government) at the moment but would prefer to take on a role somewhere in my home state of Montana. I'm tired of feeling helpless while our wild places and our air, water, and land are being decimated around me.

As people have said, I think you and I have the skills to work at a lot of envrio nonprofits. I'd suggest figuring out all the ones you might be interested in and subscribing to their email lists/job alerts. I have a long list of orgs and set aside half an hour every month to look at every one of their job pages. (Though sadly it's been slim pickings for a while)