Officials from the world’s biggest emitters of greenhouse gases met in Arlington County this week in an effort to ensure that upcoming U.N. climate negotiations in South Africa deliver at least modest results, but they left without a concrete answer.

The two-day meeting in Crystal City of the Major Economies Forum on Energy and Climate, which ended Friday afternoon, is not a formal part of the the U.N. Framework Convention on Climate Change negotiations. But it brings together countries key to any major agreement on curbing the world’s carbon output — major emitters, such as the United States, members of the European Union, China and India, and smaller developing nations, such as Ecuador and Barbados.

At the moment, countries are divided on two central questions: Should they embark on a second commitment period for the Kyoto Protocol, the current international climate pact? What sort of agreement should the world pursue by 2020? Nations that signed the 1997 agreement said they would abide by the treaty for a five-year period, from 2007 to 2012.

The Kyoto Protocol covers less than a third of the world’s current greenhouse gas emissions, because the United States failed to ratify it and because it did not impose binding targets on major emerging economies such as China and India. Japan, Russia and Canada have already announced they will not agree to a second commitment period.

“We are asking for a new global comprehensive framework, in which all countries are involved,” said Kenji Hiramatsu, Japan’s director general for global issues.

E.U. officials, meanwhile, have said they are willing to sign onto a second Kyoto commitment period, but only if all the other big emitters — including the United States, China and India — agree to begin negotiating with an eye toward forging a new, legally binding treaty at the end of the decade.

Connie Hedegaard, European commissioner for climate action, said that, when a future climate pact is being considered, “it only makes sense if these major emitters are willing to say, if not what, [then] when are you willing to say you’re willing to commit.”

But representatives from the largest developing countries have continued to resist the idea of endorsing a treaty that would impose mandatory obligations on them. On Friday, two senior Chinese officials declined to answer questions on the subject. U.S. officials argue they cannot commit to a future binding agreement without knowing what it would entail.

Todd Stern, U.S. special envoy for climate change, told reporters Friday there are “a number of countries who have a view it’s premature to decide about what the legal form of an agreement would be until you have a much better sense about what the content would be.”

Stern, who worked on forging the Kyoto Protocol when he served under President Bill Clinton, said he and his colleagues had no interest in backing a global climate agreement that could not garner sufficient political support on Capitol Hill.

“I’m quite aware of what can happen when you agree to something that’s unsustainable,” he said. “We don’t want to do that this time around.”

Daniel J. Weiss of the Center for American Progress Action Fund, the political arm of a liberal think tank in the District, said other nations were right to lobby the Obama administration to do more.

“Our allies should push the United States to play a bigger leadership role in efforts to achieve worldwide reductions in greenhouse gas pollution,” he said. But he noted that the administration has imposed tougher fuel efficiency standards on U.S. vehicles and is moving to regulate greenhouse gas emissions from power plants. “The administration is still moving forward” on climate, he said.

Hiramatsu warned that the global community should keep its expectations low when it comes to the climate negotiations that begin Nov. 28 in Durban, South Africa.

“I don’t think this will be a big breakthrough year,” he said. “The important thing is to press the process ahead, and have some clarity as to where we’re heading.”