For me, love is more powerful then fear. I do things our of love for people, animals, the earth, etc not because i fear them or the conquences.
Using your example, you want to help the earth out of fear that we will destory it and all die or whatever. I want to help the earth (and it is one of my goals to do such as well) because i love the earth. I love the earth and the trees, animals, plants, water, air, everything.
Love (for me) is more powerful then fear. If i live out of fear, i would be afraid to lose all my material possessions, that i would die etc, but because i come out of love, you can take away everything, and i still have the world, you take away the world, and i still have the sky and stars, you take that away, i still have my mind and love. It doesn't matter.
I think kids illustrate this point well. People will do things out of love for their kids that even their most powerful fear cant make then do.
Does this mean that i am passive and dont do anything to help the world? No. It means that i just approach it differently. I will help the world, help end world hungery, help bring abotu world peace, help animals, stop cutting down trees, etc. I take action to help all these things in little and big ways.
Hope that helps to explain.
Adrienne