A minor mention in a massive UN report about the need for deeper cuts in greenhouse gases by wealthy nations has emerged as a major obstacle in the negotiations for a new UN climate treaty. Developing nations at a recent UN conference in Bonn are insisting on emissions reductions of 25 to 40 percent below 1990 levels by 2020, as outlined in the report, in order to reach a deal in Copenhagen in December. However, many developed nations argue that such reductions would harm their economies. According to Yvo de Boer, the head of the UN Climate Change Secretariat, the 25 to 40 percent range has become a key benchmark for measuring the success of the Copenhagen agreement. The range of 25-40 was not included in the "summary for policymakers" of the IPCC report, which drew on the work of 2,500 experts. Shyam Saran, the special climate envoy to Indian Prime Minister Manmohan Singh, noted that little progress has been made on setting targets during the Bonn talks. Developing nations like China and India believe that the wealthy countries should aim for emissions cuts of at least 40 percent from burning fossil fuels. They argue that evidence of global warming has worsened since 2007, as seen in melting Arctic ice. Additionally, small island states, concerned about rising sea levels, are calling for emissions cuts of at least 45 percent below 1990 levels. Saran mentioned that achieving a target of forty percent by 2020 is reasonable if the problem is as large as currently believed. De Boer clarified that this level is not an agreed upon target, but rather a scenario to prevent the worst effects of global warming. Many developed nations, including the United States, believe this goal is unattainable. President Barack Obama aims to reduce U.S. emissions to 1990 levels by 2020, which would be a 14 percent decrease from 2007 levels, and by 80 percent by 2050. Japan recently set a 2020 target of 8 percent below 1990 levels. Bill Hare from the Potsdam Institute for Climate Impact Research stated that a reduction of 25 percent is still possible but will be challenging to achieve. He mentioned that recent scientific discoveries supported the range of 25-40 percent. The omission of this range from the summary was more due to technical reasons rather than doubts about its accuracy. The 25 to 40 percent range became well-known politically after being referenced on page 776 and other findings were included as a footnote in a document launching discussions on a new treaty at a meeting involving over 190 nations in Bali in 2007. Currently, wealthy nations are offering reductions of 8 to 14 percent below 1990 levels by 2020, with the European Union proposing cuts of 20 percent, or 30 percent if other developed nations also participate. The text on page 776 suggests that by 2020, developing nations should make a significant change to reduce the increase in their emissions compared to current levels. This decision has created a clear divide between wealthy and less affluent countries, instead of implementing a graduated system of emission cuts where the wealthiest nations would make the largest reductions. According to Alden Meyer from the Union of Concerned Scientists, both sides believe they are being burdened with excessive responsibilities. It is uncertain how this impasse will be resolved, as the wealthy countries may propose deeper cuts while poorer nations might compromise in exchange for clean technologies and increased aid. Hare mentioned that Russia, the only major country yet to establish a greenhouse gas goal, could have a significant impact as its emissions are already approximately 30 percent lower than 1990 levels following the Soviet Union's collapse. If Russia were to set a 2020 goal at current levels, it would further reduce overall promised cuts to between 12 and 18 percent. However, some countries argue that cuts do not necessarily have to fall within this range, especially if future reductions are more substantial. Jonathan Pershing, leader of the US delegation in Bonn and an IPCC author, suggested that other possibilities exist during a briefing at the end of last month.