By SHAI OSTER
BEIJING -- China signaled a slightly softer position on accepting a cap on the emissions that cause global warming, despite expressing frustration at the lack of a breakthrough on climate-change talks.
Disagreement over whether China and other developing countries should accept such emissions caps is a key impediment to negotiating a successor pact to the 1997 Kyoto Protocol on climate change in time for a planned December meeting in Copenhagen. China and the U.S. in recent months have made reaching a deal in time for Copenhagen a central element of their bilateral relationship.
Yu Qingtai, China's special envoy for the climate-change negotiations, emphasized the importance of reaching a deal. "The talks on climate change have been going on quite slowly. We only have a few months left before Copenhagen," said Mr. Yu, who welcomed efforts by the U.S. to pass a domestic climate bill. "The nature of the problem is such that we can't afford a failure."
Replacing the old pact, which expires in 2012, will be high on the agenda when U.S. President Barack Obama meets Chinese President Hu Jintao on the sidelines of a United Nations meeting in New York in September, and again when Mr. Obama visits China later in the year.
So far, China has refused any limits on emissions, arguing they would be a form of economic discrimination against poorer countries. China also says that 20% of its carbon emissions comes from products made for export and that it shouldn't bear the burden.
But China appears to have shifted subtly recently, with some influential Chinese economists arguing that China might soon be rich enough to afford some of the changes necessary to combat global warming.
Mr. Yu also offered a sign that China is taking the first steps toward figuring out how much it could cap while still growing enough to reach its economic goals. He said Chinese scientists were looking at what would be China's peak emissions, or the level at which economic growth could continue and emissions could be cut back.
China and the U.S. are still miles apart. China, driven by a historically unprecedented wave of urbanization and industrialization, has recently surpassed the U.S. as the top emitter of greenhouse gasses. But Beijing insists that rich industrialized countries have a responsibility to clean up first.
Rich countries like the U.S. should cut their emissions at least 40% from their 1990 levels by 2020, China says -- a schedule much more aggressive than ones being considered in the U.S. or Europe. In addition, China wants money and technology for itself and other developing nations to smooth the adjustment to a low-carbon economy. "This isn't charity, but their responsibility," Mr. Yu said.
On the other side, countries like the U.S. say big countries like China and India are growing so fast that, unless they accept absolute limits on their greenhouse gasses, the extra pollution from all of their new factories obliterate gains made elsewhere, gutting the value of any deal.—Wan Xu contributed to this article.
Write to Shai Oster at shai.oster@wsj.com