President Obama, who had planned to speak at the climate change summit in UN summit on climate change in Copenhagen on Wednesday, will now only arrive on Dec. 18, the White House said Friday.

Obama had earlier said he would stop in Copenhagen on Dec. 9, on his way to collecting his Nobel Peace Prize in Oslo, Norway.

The White House said this was done because Obama believes that continued US leadership can be most productive through his participation at the end of the Copenhagen conference.

The delay gives negotiators more time to work out remaining issues, he added. Obama will also be at the summit with more global leaders, including those from the high-growth, high-polluting states of China and India.

The summit aims to draw up a treaty to succeed the 1997 Kyoto Protocol.

Following bilateral meetings with the President and since the United States announced an emissions reduction target that reflects the progress being made in Congress towards comprehensive energy legislation, China and India have for the first time set targets to reduce their carbon intensity, the White House said.