The United Nations urged rich nations today to keep a pledge to give $30 billion to poor nations by 2012 to cope with climate change, saying it was "not an impossible call" despite budget cuts in Europe, Reuters reported. Yvo de Boer, head of the U.N. Climate Change Secretariat, also said it was extremely unlikely that a new U.N. climate treaty would be agreed in 2010 after the Copenhagen summit in December fell short of a full, legally binding treaty. He said that one priority for 2010 was for rich countries to deliver on key elements of that Copenhagen Accord, including a promise of $10 billion a year in aid from 2010-12 for developing nations, rising to $100 billion a year from 2020. "Of course times are harsh, especially in Europe, but raising $10 billion a year for three years among all industrialised countries is not an impossible call," he said. "It will establish greater trust" between rich and poor nations, he said in a briefing before talks among officials from 190 nations in Bonn from May 31 to June 11 preparing for ministerial talks in Cancun, Mexico, near the end of 2010. Poor nations say they will need ever more cash to shift from fossil fuels towards renewable energies, such as wind and solar power, and to start adapting to impacts of climate change such as more droughts, floods and rising sea levels. "I think it's extremely unlikely we will see a legally binding agreement in Cancun," de Boer said. "Having a treaty, if we are to get to a treaty, in South Africa a year later would be much more realistic." South Africa hosts the next annual ministerial meeting in late 2011. Many nations also say that there are only scant chances of a deal in 2010 after Copenhagen fell short.