OSLO/SINGAPORE - Efforts to extend the Kyoto climate pact framework risk collapse in a setback to years of diplomatic bargains, as chances fade that the United States will join other rich nations in capping emissions. December's UN climate conference in Denmark failed to cite the UN-brokered Kyoto pact as a touchstone …quot; sapping hopes for a global carbon price to guide billions of dollars in investments from nuclear plants to solar panels. "We are probably seeing the beginning of the end for the Kyoto Protocol in its current form," said Johan Rockstrom, head of the Stockholm Resilience Centre at Stockholm University. "But it's also very clear that we are still in a situation where there is no alternative. So we are in a fix." Plans to extend the Kyoto Protocol, the world's main pact for fighting climate change, beyond 2012 hinge on bridging a divide between rich and poor countries over the cost of switching from carbon-intensive technologies. The Denmark summit came up with a Copenhagen Accord aimed at limiting global warming to below 2 degrees Celsius (3.6 F) above pre-industrial times, and also pledged $100 billion a year from rich nations in climate aid for the poor from 2020. But the accord barely mentions Kyoto, which binds 37 rich nations excluding the largest emitter, the United States, to cut greenhouse gas emissions by an average of five per cent below 1990 levels between 2008-12. Developing nations led by China and India insist the rich must extend the Kyoto protocols to 2020 before they take on commitments to slow rising emissions in a new treaty also with 2020 targets for all nations. US President Barack Obama has tried to commit mandated cuts in US emissions "in the range of 17 per cent" below 2005 levels by 2020, a cut of four per cent below 1990 levels. But the US Senate has stalled legislation in that direction. Obama announced this week $8.3 billion in loan guarantees to build the first US nuclear power plant in the US in nearly three decades to help break the legislative logjam by cajoling conservatives to support a climate bill, though analysts say it's unlikely to work. "It's not just the Protocol that looks in danger, the whole legal architecture for post-2012 looks in danger," said Stephen Howes, a director at the Crawford School of Economics and Government at the Australian National University in Canberra. "Whether we'll have a legal architecture in place by 2012 looks very questionable." With no legal certainty, Kyoto could split into a patchwork of unilateral promises to fight climate change, such as the European Union's (EU) plan to cut emissions by 20 per cent from 1990 levels by 2020. "There is a risk of Kyoto dissolving," said Jennifer Morgan, climate and energy programme director of the World Resources Institute in Washington.