Bolivia played host to the People's World Conference on Climate Change and Mother Earth Rights, welcoming more than 20,000 environmental activists and representatives from 125 countries.
Alicia Barcena, the head of the Economic Commission for Latin America and the Caribbean, delivered a message from U.N. Secretary-General Ban Ki-moon calling for a concerted effort to save the planet.
"Climate change is an ethical issue with serious implications for the well-being of our generation and those that will follow," she said. "It requires a global solution that takes into account the views and needs of all who share Mother Earth, our only home."
Bolivian President Evo Morales was greeted with cheers when he blamed aggressive economic activity for wreaking havoc on the environment.
"Capitalism is the chief enemy of humanity, synonymous with inequality and destruction of the planet," he was quoted by Inter Press Service as saying.
The summit opened Tuesday in Cochabamba, Bolivia, with a ceremony from Andean priests and indigenous people from across the world.
Barcena added that the United Nations seeks an inclusive and transparent dialogue on global climate change.
"Our efforts must be much more ambitious to satisfy what science tells us is needed to stabilize our climate," she said.