Brazil's President Dilma Rousseff on Sunday promised big cuts in greenhouse gas emissions by 2025.
Using 2005 as the baseline level, the reduction target will be 37 percent over the next decade and 43 percent by 2030, she said at a United Nations development conference.
Its goal is to strike a binding, global agreement on how to curb climate change.
Previous such gatherings have failed as rich polluters like the United States proved unable to reach agreement with big-polluting developing states such as China and Brazil.
Rousseff said the Paris conference will provide a "unique opportunity" to forge a common front.
At the Paris summit Brazil will also pledge to recover degraded pastures and make available 12 million acres (five million hectares) of "integrated crop-livestock-forest area."
"We have been diversifying renewable sources in our energy mix, which is one of the cleanest in the world," Rousseff said.