The Centre for Social Media at American University has a great webpage outlining the ‘Best Practices for Sustainable Filmmaking’. They cover everything from feeding yourself ethically on a shoot to calculating the carbon budget for your project. Some great tips here to help you practice what you preach if you are making films about environmental awareness. It may not be possible to do everything on this list immediately, but lots of food for thought.
Make sure to read right to the bottom; you can download a PDF and all the related documents there.