Chinese President Hu Jintao has announced that his country aims to significantly curb its carbon emissions over the next decade, by a “notable margin” by 2020 from the 2005 levels.

The move prompts hopes that a global climate deal could be reached at the Copenhagen climate conference in December. Whether China – as a leader of the fast growing developing nations who are heavy emitters – acts on climate change is seen as critical to the potential of a deal.

Jintao made the announcement at the United Nations in New York, in the lead up to the G20 meetings in the US this week.

His statement came just weeks after another developing country that is a big polluter, India, also implied domestic action on climate change.

“We have to take up bold new responsibilities that we have evaded so far,” Jairam Ramesh, India’s environment minister, said at a recent trade conference. “But if we want durable political consensus, then it has to be rooted in domestic legislation and not in an international agreement.”