I began working for the Earth in 1973, and have done so -- in different ways -- for the last 36 years. Some ups, lots of downs. Mostly I think because environmenalists have taken a pessimistic and antagonistic approach to change.
I agree with Paul that that a realistic optimism is key. And a vision-driven, reality-grounded approach to creating what matters seems to work far better than so called "problem solving." The age of problem solving has created more and worse problems than it's solved. We need to usher in a new age of "creating" -- focused on mastering the act of creating what we love, and want to see in our lives, work and world.