Kenyan environmentalist Professor Wangari Maathai received the Nobel Peace Prize today for her work to combat deforestation and to promote democracy and women's rights.
Saying the planet is under threat from human activities, Prof Maathai urged democratic reforms and an end to corporate greed in her acceptance speech.
Prof Maathai, who is Kenya's deputy environment minister, received a gold medal and a Nobel diploma at a ceremony in Oslo City Hall to applause from about 1,000 guests.
In her speech Prof Maathai said that sweeping changes to the world order were needed to restore a "world of beauty and wonder" by overcoming challenges ranging from AIDS to climatic instability.
"Today we are faced with a challenge that calls for a shift in our thinking, so that humanity stops threatening its life-support system," she said.
"I call on leaders, especially in Africa, to expand democratic space and build fair and just societies that allow the creativity and energy of their citizens to flourish"
"Further, industry and global institutions must appreciate that ensuring economic justice, equity and ecological integrity are of greater value than profits at any cost".
She said that "destruction of ecosystems ... climatic instability and contamination of soils and waters" all contributed to poverty.
"The state of any country's environment is a reflection of the kind of governance in place, and without good governance there can be no peace".
Prof Maathai is the first African woman to win and the 12th female peace laureate since the award was first made in 1901.