President Barack Obama will personally commit the U.S. to a 17 percent emissions reduction over the next decade, on the way to reducing pollution by 80 percent by mid-century, the White House said.

The 17 percent target is up from the 14 percent below 2005 levels by 2020 — equivalent to a return to 1990 emissions levels — that Obama announced in November 2008 Obama. It is also within the lower range of targets for the proposed cap-and-trade scheme proposed in legislation currently under discussion in the US Congress (between 17 and 20 percent below 2005 levels).

Obama will attend the start of the conference on December 9, before heading to Oslo to accept the Nobel Peace Prize. He is one of nearly 70 leaders attending.

Yvo de Boer, the United Nations climate chief, said it is important for the United States to establish emissions reduction targets and a financial commitment to helping developing countries address climate change.

“If he comes in the first week to announce that, it would be a major boost to the conference,” de Boer told The Associated Press. He said Obama’s participation was critical because delegates “are looking to the United States to come forward.”