Prof. Wangari Muta Maathai started the Green Belt Movement in 1977, working with women to improve their livelihoods by increasing their access to resources like firewood for cooking and clean water. She became a great advocate for better management of natural resources and for sustainability, equity, and justice. A synopsis of her life and work can be read here.
In addition to her work with the Greenbelt Movement, Maathai founded the Mazingira Green Party of Kenya. The Daily Nation in Nairobi gives an interesting perspective on her brave efforts and extensive accomplishments. Greens and others of good will across the globe will miss her deeply.