Barack Obama will commit the US to substantial cuts in greenhouse gas pollution over the next decade following the decision to travel to crucial climate change talks in Copenhagen next month.
The move comes despite resistance in the US Congress over higher costs, writes The Press Association.
The US president will attend the start of the conference on 9 December, where he will "put on the table" a commitment to cut emissions by 17% over the next decade, on the way to reducing heat-trapping pollution by 80% by mid-century, the White House said.
Cutting US carbon dioxide emissions by one-sixth in just a decade would increase the cost of energy as electric utilities pay for capturing carbon dioxide at coal-burning power plants or switch to more expensive alternatives.
UN climate chief Yvo de Boer said it is important for the US to establish emissions reduction targets and a financial commitment to help developing countries address climate change.