I joined the DC Green Muslims group for several reasons: social, environmental and economic... but mostly because I believe that the Muslim imperative to bring religious meaning and spirituality to all parts of life also applies to our connection to nature (this includes people, too!).
This connection to nature is inherent to Islam. It is part of our fitra, our true nature. So instead of asking what it is in our past that inspires us to be environmentally conscious (i.e. "green"), the question should be what has left us environmentally unconscious? i.e. in a state of ghafla.