Wangari Muta Maathai was born in Nyeri, Kenya, in 1940. She was trained in biological sciences and received a doctorate from the University of Nairobi, where she also taught veterinary anatomy. She became Chair of the Department of Veterinary Anatomy and an associate Professor in 1976 and 1977 respectively, being in both cases the first woman in the region to attain these positions.

Maathai was active in the National Council of Women of Kenya from 1976 and was its chairman, 1981-87. It was through the Council that she introduced the idea of planting trees with the people and developed it into a broad-based, grassroots organisation designed to conserve the environment and improve women's quality of life. By the end of 1993 the women reported that they had planted over 20 million trees on their farms and on school and church compounds.

The Green belt Movement grew very fast. By the early 1980s there were estimated to be 600 tree nurseries, involving 2,000-3,000 women. About 2,000 public green belts with about a thousand seedlings each had been established and over half-a-million school children were involved. Some 15,000 farmers had planted woodlots on their own farms.

In 1986 the Movement established a Pan African Green Belt Network and has introduced over 40 individuals from other African countries to its approach. This has led to the adoption of Green Belt methods in Tanzania, Uganda, Malawi, Lesotho, Ethiopia, Zimbabwe and some other countries of the region.

The Green Belt Movement set itself both short- and long-term objectives. The overall aim has been to create public awareness of the need to protect the environment through tree planting and sustainable management. More specifically, it has initiatives to promote and protect bio-diversity, to protect the soil, to create jobs especially in the rural areas, to give women a positive image in the community and to assert their leadership qualities. It has made tree planting an income-generating activity. It promotes food security and assists people to make the link between environmental degradation and many of the problems they face, including poverty and livelihood insecurity.

Over its first 20 years, many of the Movement's objectives have been achieved. Environmental awareness has been greatly increased in the country, and many women's groups have sold millions of seedlings to the Movement, using the income to meet immediate domestic needs such as education of their children or investing it in other income-generating ventures. Tree planting has become an honourable activity and many people have adopted it. Relevant knowledge and techniques have been imparted to the participants and many women have become 'foresters without diplomas'. There are now over 3,000 tree nurseries and more than 3,000 part-time jobs have been created.

In recent years Wangari Maathai's own work has focused on the human rights situation in Kenya. Standing up for a democratic, multi-ethnic Kenya, she has been subjected to defamation, persecution, detention and physical attacks.

In 2004 she was awarded the Nobel Peace Prize.