Chinese President Hu Jintao (4th L) poses for photos with other leaders at the UN headquarters in New York Sept. 22, 2009. President Hu and the other leaders were attending the UN Climate Change Summit in New York Sept. 22. [Ju Peng/Xinhua]

The United Nations concluded on Tuesday a day-long summit on climate change, with UN Secretary-General Ban Ki-moon urging world leaders to act speedily to ensure a successful outcome at the upcoming UN climate conference in Copenhagen in December.

"I was heartened to hear that a growing number of leaders are prepared to move beyond purely national perspectives to global leadership," Ban told world leaders at the closing session of the summit.

"You have undertaken to remain engaged until a deal has been sealed in Copenhagen. And you have agreed to give guidance to your negotiators to work toward an ambitious, effective and fair deal in Copenhagen," he said.

Calling climate change "a defining challenge of our time," Ban said that the summit signaled the determination of world leaders to address this challenge and reach a substantive deal in Copenhagen.

"All of you support the urgent need to step up action and raise the financial resources needed to make this happen," the secretary-general said.

In a summary of the message of the summit, Ban said that that the Copenhagen deal must be comprehensive and ensure:

- enhanced action to assist the most vulnerable and the poorest to adapt to the impacts of climate change;

- ambitious emission reduction targets for industrialized countries;

- nationally-appropriate mitigation actions by developing countries with the necessary support;

- significantly scaled-up financial and technological resources; and

- an equitable governance structure.

Nearly 100 heads of state and government participated in the summit, the largest-ever gathering of world leaders to discuss climate change.

By convening the event, the secretary-general hoped to mobilize the political will and generate the momentum needed to reach an ambitious agreement at the Copenhagen conference.