Brazil says it will voluntarily reduce carbon emissions by 36.1 percent to 38.9 percent by 2020.
Dilma Rousseff is chief of staff for President Luiz Inacio Lula da Silva. She says the cuts Brazil will present at a climate summit in Copenhagen next month will be on a voluntary basis only. She says the nation will not accept mandatory cuts.
Brazilian Environment Minister Carlos Minc has said the majority of Brazil's emission cuts will come from slowing deforestation, which scientists think is responsible for 20 percent of the globe's carbon emissions.
Rousseff announced the cuts Friday following a meeting with Silva and Minc.
On Thursday, Brazil announced that it had registered its biggest annual decline in deforestation.