By Laura Trevelyan
BBC News, UN, New York
The top UN official on climate change says the failure of world leaders to agree on global warming means it is time for the UN to take the lead.
There is little agreement on how to deal with a changing climate
Yvo de Boer, head of the UN Climate Secretariat, wants a summit of world leaders to talk about what happens when the Kyoto Protocol expires in 2012.
Despite rising sea levels, there is no agreement on how to deal with global warming's long-term threat.
In fact, Mr de Boer says, the process is getting more and more stuck.
Mr de Boer says it is vitally important for the world to agree on how carbon emissions should be curbed after 2012.
But, he points out, there are so many different countries with different needs: developing nations, for example, want their economies to grow and they do not want to take any action that might make them uncompetitive; while the US and Australia have backed away from even endorsing Kyoto.
Mr de Boer says only the UN can bring all the competing groups together.
"I feel it is so important to bring the question of climate change back to the UN process," Mr de Boer said.
"Back to the UN framework convention on climate change, where basically all of the interests can be addressed and you can find a solution for after 2012 that really does represent the diversity of use."
The new UN Secretary General, Ban Ki-moon, has said tackling climate change is a priority for him.
In a speech in Washington on Thursday, Mr Ban said climate change was an all-encompassing threat to the coastal cities in which nearly half the world's population live.