Wangari Maathai, the late environmental and political activist from Kenya, was announced as the winner of the Nobel Peace Prize on October 8, 2004, for what the Norwegian Nobel Committee called "her contribution to sustainable development, democracy and peace." She was the first African woman to receive the prize in its 104-year history.

Maathai was honored chiefly for her environmental activities in Kenya. In 1977, she started the Green Belt Movement, a grassroots tree-planting campaign aimed at combating soil erosion and deforestation while also providing fuel for cooking in rural villages where women were often forced to walk miles in search of firewood. By 2004, the Green Belt Movement had planted over thirty million trees, provided work for tens of thousands of women, and seen its efforts replicated in countries across Africa.

What was distinctive about Maathai's work, the Nobel Committee said in its announcement, was that it was as much about promoting democracy, empowering women, and safeguarding human rights as it was about protecting the environment. For Maathai, there was a direct connection between the depletion of natural resources and the failures of Kenya's authoritarian government. Indeed, she had taken on Kenya's ruling party and its autocratic president, Daniel arap Moi, on numerous occasions during the 1980s and 90s. Though she was vilified by the government, arrested more than a dozen times, and even beaten by police, her methods proved surprisingly effective.

"Maathai stands at the front of the fight to promote ecologically viable social, economic and cultural development in Kenya and in Africa," Nobel Committee chairman Ole Danbolt Mjøs said in the statement. "She has taken a holistic approach to sustainable development that embraces democracy, human rights and women's rights in particular. She thinks globally and acts locally."

The award to Wangari Maathai was the first ever to an environmental activist, and some critics were quick to seize on what they saw as a tenuous link between ecological issues and world peace. "What does tree planting have to do with peace?" the Norwegian newspaper Aftenposten asked. Carl I. Hagen, leader of Norway's Progress Party, insisted that the Nobel Committee had betrayed a century-old focus on resolving armed conflict. "You don't give the Nobel chemistry prize to a professor in economics," he told Reuters. "A peace prize should honor peace, not the environment."

Wangari Maathai was the first African woman and the first environmentalist to win the prize in its 104-year history. In selecting her, the Norwegian Nobel Committee was following a broader mandate than the one outlined in Alfred Nobel's will — a fact that some critics were quick to seize upon.

In selecting Wangari Maathai, the Norwegian Nobel Committee was clearly following a broader mandate than the one outlined in Alfred Nobel's will. Nobel had stipulated that the peace prize was for "the person who shall have done the most or the best work for fraternity between nations, for the abolition or reduction of standing armies and for the holding and promotion of peace congresses." Over the years, however, successive Nobel Committees have used the phrase "fraternity between nations" to give an ever broader interpretation to peacemaking. As long ago as 1930, then chairman Fredrik Stang declared that the Committee considered it its duty to be on the watch for all developments that may have had potential for bringing peace. Former chairman Egil Aarvik echoed the point in explaining the rationale behind human rights prizes. Nobel's will does not specifically refer to human rights, he said, because it reflects a nineteenth-century conception of peace. "Today, we realize that peace cannot be established without a full respect for freedom."

When asked by reporters if the Nobel Committee had stretched the traditional bounds of the prize in giving the award to Wangari Maathai, chairman Mjøs replied: "It is clear that with this award, we have expanded the term 'peace' to encompass environmental questions."

In his presentation speech at the December award ceremony, he returned to the point, saying that the Committee had broadened its definition of peace to emphasize its crucial environmental dimension. "When we analyze local conflicts, we tend to focus on their ethnic and religious aspects," he said. "But it is often the underlying ecological circumstances that bring the more readily visible factors to the flashpoint." He made reference to conflicts in many parts of the world — Darfur, Chiapas, Haiti, and the Amazon, among others — which illustrate that deforestation, in combination with other pressing problems, can be a source of violent conflict.

He went on to predict that within a few decades the connection between environmental issues, natural resources, and armed conflict will seem "almost as obvious as the connection we see today between human rights, democracy and peace." Meeting our most urgent environmental problems will require "international cooperation across all national boundaries on a much larger scale than we have seen up to now," he asserted. "We live on the same globe. We must all cooperate to meet the world's environmental challenges. Together we are strong, divided we are weak."

Wangari Maathai accepted the prize in an unusually festive award ceremony that included African drumming and performances by a Kenyan dance troupe. Over 1,000 guests filled the lavishly decorated auditorium of Oslo City Hall, including a large delegation of Africans, many of them cheering, whistling and waving small hand flags. The audience also included the Norwegian royal family, numerous heads of state and foreign dignitaries, even a handful of Hollywood celebrities.

Dressed in a bright orange gown with a matching headband, Maathai said she was humbled and uplifted by the award and accepted it "on behalf of the people of Kenya and Africa." In recognizing her for the prize, she said, "the Norwegian Nobel Committee has placed the critical issue of the environment and its linkage to democracy and peace before the world. Recognizing that sustainable development, democracy and peace are indivisible is an idea whose time has come."

In her 21-minute Nobel lecture, Maathai looked back on her work over three decades. The Green Belt Movement, together with other civil society organizations and the Kenyan people as a whole, had much to be proud of, she said — most notably, the peaceful transition to democratic government in 2002. Yet there were still a host of critical challenges. "In the course of history, there comes a time when humanity is called to shift to a new level of consciousness, to reach a higher moral ground. A time when we have to shed our fears and give hope to each other." That time, she said, is now. "Today we are faced with a challenge that calls for a shift in our thinking, so that humanity stops threatening its life-support system. We are called to assist the Earth to heal her wounds and in the process heal our own — indeed, to embrace the whole creation in all its diversity, beauty and wonder."

This essay was adapted from the book, Nobel Lectures in Peace, 2001-2005, edited by Irwin Abrams and Scott London (published by World Scientific, 2009).