 About 40 world leaders plan to go to Copenhagen next month to improve the chances of clinching a UN climate deal, the United Nations said on Friday as preparatory talks ended with scant progress. Developing nations in Barcelona accused rich countries of trying to lower ambitions for a 190-nation deal in Copenhagen with suggestions that up to an extra year may be needed to tie up details of a legally binding treaty. Inviting world leaders to the end of the Copenhagen meeting on Dec. 7-18 could help overcome disputes, said Yvo de Boer, head of the UN Climate Change Secretariat, on the final day of the week-long Barcelona talks. "My understanding is that 40 heads of state have indicated their intention to be present," he said. They include British Prime Minister Gordon Brown and French President Nicolas Sarkozy as well as leaders of African and Caribbean nations. German Chancellor Angela Merkel is considering attending, a spokesman said in Berlin. U.S. President Barack Obama is among those undecided. Danish Prime Minister Lars Lokke Rasmussen has not formally invited leaders to the talks, currently due to be limited to environment ministers. "There is no official figure" of how many leaders will come, a Danish spokesman said. The 175-nation Barcelona meeting ended with little progress towards a deal but narrowed options on helping the poor to adapt to climate change, sharing technology and cutting emissions from deforestation, delegates said. RICH-POOR SPLIT The meeting exposed a continuing rich-poor split on sharing the burden of curbs on greenhouse gas emissions in a drive to avert droughts, wildfires, species extinctions and rising seas. It also opened a new rift on what was achievable in Copenhagen. Rich nation delegates said there was time to agree in December a "political deal", followed by a legal text six to 12 months later. Any notion of such a delay must be "dismissed", said India's Shyam Saran, Prime Minister Manmohan Singh's climate envoy, and many developing nations said Copenhagen must be legally binding. "Developed countries are acting as a brake towards any meaningful progress" said Lumumba Stanislaus Di-Aping of Sudan, chair of the Group of 77 and China, representing poor nations. African nations boycotted some talks on Tuesday in protest. "Lives and the very existence of whole nations are at stake," said Dessima Williams of Grenada, representing small island states which say they risk being swamped by rising sea levels. She said a Copenhagen deal had to be legally binding and also rejected talk of a delay. De Boer said Copenhagen "can and must be the turning point in the international fight against climate change" but said time was too short to seal a full legal treaty in 2009. He said Copenhagen should at least set 2020 greenhouse gas emissions goals for all rich nations, agree actions by the poor to slow their rising emissions and agree ways to raise billions in funding and mechanisms to oversee funds. "I believe that the US can commit to a number in Copenhagen," de Boer said. "That's a decision yet to be made," Jonathan Pershing, head of the US delegation, said when asked if Obama could bring a number in December. The US delegation wants a target to be guided by its Senate. A US climate bill cleared a key panel on Thursday but is unlikely to pass the full Senate before Copenhagen. Activists criticised a lack of leadership in the run-up to Copenhagen, including from Obama. Two protesters wandered the conference hall dressed as aliens with green faces on Friday asking: "Where are your climate leaders?" in robotic voices. "Where is the great Rudd?", one of them asked a group of Australian delegates, referring to Prime Minister Kevin Rudd. In St Andrews, Scotland, British finance minister Alistair Darling said he would seek progress to raise cash to fight climate change at a Group of 20 finance ministers' meeting.