BEIJING, Dec 20 (Reuters) - China is glad a climate change roadmap agreed last week in Bali has drawn the United States to the negotiating table, but the world's only superpower must do more to tackle global warming, a top official said on Thursday.

Yu Qingtai, China's climate change ambassador, said Beijing was satisfied with the hard-won plan, finally agreed after two weeks of talks overran by a day into a dramatic final session marked by tears, booing and a series of standing ovations.

Nearly 200 nations agreed to launch negotiations on a new pact to fight global warming after a last-minute reversal by the United States allowed a breakthrough.

The deal is important because it draws in countries that currently do not have a binding international obligation to cut greenhouse gas emissions, Yu said, but they could still do more to help others.

"The United States is an important contributor of emissions both in total and on a per-capita basis. It has both advanced technology and ample funds," he told a briefing.

"So on the issue of tackling climate change, America should display a more positive, more constructive role."

China says rich nations should bear much of the burden for tackling global warming in the short term because of their historic responsibility for causing the problem.

Developing nations want more help with technology and cash for adapting to a warmer world and Yu said the poorest countries, still struggling to feed their people, could not be expected to pay for expensive emissions-cutting technology.

"Giving very detailed targets to the least developed countries is not realistic because they do not have this kind of capacity. Their most important problem is making sure their people are fed and sheltered," he said.

China's rapidly growing economy means it is no longer at this level, and it is expected to overtake the United States as the top emitter of carbon dioxide as early as this year -- bringing international pressure to curb emissions.

Beijing says domestic energy efficiency targets are already having an impact but Yu also told Reuters before the Bali talks that Beijing would be willing to do more in return for Western help with clean technology.

He also shrugged off the impact of an intervention by his delegation which had caused the head of the U.N. Climate Change Secretariat, Yvo de Boer, to rush out near to tears and brought angry rebukes from at least one other developing nation delegate.

"The intervention wasn't directed at a specific person, it was just to ensure that there was a smooth process," Yu said, adding that China supports de Boer's work. (Reporting by Emma Graham-Harrison; Editing by David Fogarty)

AlertNet news is provided by