 The world should at least halve greenhouse gas emissions by 2050 with rich nations taking the lead, according to a first draft text on Friday seeking to break deadlock on a new climate pact at U.N. talks. The 7-page document omits figures for how many billions of dollars the rich nations should give developing nations to help them shift to green energies and cope with the impact of global warming, such as desertification and rising sea levels. "Parties shall cooperate to avoid dangerous climate change," according to one text, proposed by Michael Zammit Cutajar of Malta, who chairs talks on long-term action by all nations at the December 7-18 meeting on a new climate pact in Copenhagen. The text offers a range for global cuts in greenhouse gas emissions, mainly from burning fossil fuels, of either at least 50, 85 or 95 percent by 2050 from 1990 levels. More than 110 world leaders will attend a closing summit on December 18. The numbers were bracketed, showing there is no agreement. The text also offered options for rich nations' cuts in emissions starting at 75 percent and ranging to more than 95 percent below 1990 levels by 2050. Yvo de Boer, head of the U.N. Climate Change Secretariat, said the documents marked a "step change" in the negotiations. "It's time to focus on the bigger picture," he told reporters. Developing nations led by China and India have in the past rejected signing up for a halving of world emissions by 2050 unless rich nations first take far tougher action to cut their emissions and provide funds to help the poor. "We are still considering the text," said Kemal Djemouai, an Algerian official who chairs the group of African nations. Alden Meyer, of the Union of Concerned Scientists, said there were huge gaps in the text. "I don't think developing countries will accept a global goal for 2050 without more on long-term funding," he said. But he said it was a good basis for future work.