The United States rejected fresh demands that it accept ambitious guidelines for negotiating future cuts in emissions of global-warming gases, as the UN climate conference entered its last days. Pressure came even from a one-time ally on climate, Australia, whose new prime minister urged Washington to "embrace" new binding targets. But UN Secretary-General Ban Ki-moon, after opening the ministerial-level final segment of the two-week meeting, told reporters Wednesday he believed suggesting specific emissions guidelines in the "Bali roadmap" for future talks may prove "too ambitious." The tenor of the talks, which run through Friday, pointed instead toward a least-common-denominator outcome by week's end: a vague plan to negotiate by 2009 a new deal on emissions cutbacks, replacing the Kyoto Protocol when it expires in 2012. The warming climate, meanwhile, seemed to pursue its own accelerated timetable. Through November, the year 2007 ranked as the globe's second-warmest on record, after 2005, NASA's Goddard Institute of Space Studies reported Wednesday. The latest NASA satellite data, meanwhile, showed Arctic Ocean ice melted last summer at an even greater rate than found previously, The Associated Press reported from Washington. One NASA scientist said the Arctic might be almost ice-free in the summer of 2012, much sooner than predicted just months ago. In a series of authoritative reports this year, the Nobel Prize-winning UN network of climate scientists warned of severe consequences - rising seas, spreading droughts, extinguished species, intensified heat waves - if the world's nations don't sharply reduce emissions of carbon dioxide and other heat-trapping emissions from industry, transport and agriculture. The scientists projected seas could rise as much as 0.59 meters in this century as they expand from warmth and from the runoff of melting land ice. The rise could be much higher if melt quickens in Greenland and Antarctica. The growing threat drew emotional appeals from islanders among the more than 180 nations at the Bali talks. "It is a story of untold human dimensions, of people becoming environmental refugees," Grenada's Angus Friday told the hundreds of assembled delegates. Some islands are already beset by encroaching seas, he said, adding, "No island should be left behind." The task before the annual UN climate treaty conference was to agree on a "Bali roadmap" launching negotiations for an agreement to succeed the Kyoto Protocol, a treaty annex requiring 36 industrial nations to reduce greenhouse-gas emissions by an average 5 percent below 1990 levels by 2012. The United States rejects the Kyoto deal, President George W. Bush complaining it would harm the US economy and cutbacks should have been imposed on such poorer but fast-developing nations as China and India. The Bush administration instead promotes a voluntary approach to reducing emissions. An early draft of the conference decision document here at Bali says nations should negotiate the post-2012 pact while recognizing that deeper cuts, in the "indicative range" of 25-40 percent below 1990 levels by 2020, will be required. And the draft specifies "quantified commitments" - not voluntary measures. The US delegation heard entreaties from many quarters here to change its position. In the next round, "we expect all developed countries to embrace a further set of binding emissions targets," said Prime Minister Kevin Rudd, whose new Australian government last week ratified Kyoto, leaving the US alone as a major industrial nation repudiating that pact. Indonesia's Susilo Bambang Yudhoyono, the host president, drew enthusiastic applause when he singled out the Americans. "We must ensure that the United States of America, as the world's biggest economy, the largest emitter of greenhouse gas, and the world leader in technology, is part of such a post-2012 arrangement," he declared. The US delegation, meanwhile, stuck to its previous rejection of specific guidelines. "Once numbers appear in the text, it predetermines the outcome," said chief US negotiator Harlan Watson. Secretary-General Ban, who is taking an unusual personal role in the climate talks, told reporters that "somewhere down the road" targets will be necessary, but for now "it may be too ambitious."