Environmentalists tend to get pigeonholed as spoiled, self-righteous hippies obsessed with a trivial cause; Maathai's work is a good demonstration of how fundamental the protection of natural resources is to sustainable development, democratic governance, and international peace. She explains it best, so go ahead and read her Nobel Lecture.
Here's a start:
I stand before you and the world humbled by this recognition and uplifted by the honour of being the 2004 Nobel Peace Laureate.
As the first African woman to receive this prize, I accept it on behalf of the people of Kenya and Africa, and indeed the world. I am especially mindful of women and the girl child. I hope it will encourage them to raise their voices and take more space for leadership. I know the honour also gives a deep sense of pride to our men, both old and young. As a mother, I appreciate the inspiration this brings to the youth and urge them to use it to pursue their dreams.