There are more effective ways of tackling environmental problems including global warming proliferation of plastics urban sprawl and the loss of biodiversity than by treaties top-down regulations and other approaches offered by big governments and their dependents.
Your work is going to fill a large part of your life and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven't found it yet keep looking. Don't settle. As with all matters of the heart you'll know when you find it.