Developing countries at the Copenhagen conference are furious over a leaked Danish document that they say would burden them with the brunt of curbing greenhouse gas emissions.
But the United Nations and Denmark have downplayed its significance. The document is nearly two weeks old and a "working paper," meaning it was only intended as a draft agreement to consult with a select few countries.
Critics, including the World Wildlife Fund, said the document showed Denmark had little intention for fresh negotiations at the climate conference.
"The behind-the-scenes negotiation tactics under the Danish presidency have been focusing on pleasing the rich and powerful countries rather than serving the majority of states who are demanding a fair and ambitious solution," said Kim Carstensen, head of the climate initiative for the WWF.
Meanwhile, the World Meteorological Organization said Tuesday that the decade ending Dec. 31 will likely be the warmest ever recorded, and 2009 should be one of the 10 warmest years on the books.
When compared with records dating back to 1850, the average temperature for the 2000s is expected to surpass those from the next two warmest decades, the 1990s and the 1980s, according to a report issued by the organization on Tuesday.
Based on preliminary data, the WMO said the January to October period in 2009 was nearly half a degree warmer than the average temperature from 1960 to 1990 -- further evidence, the group contends, of a warming trend.
For some regions in Africa and Asia, 2009 will probably be the warmest year on record. But the global average is expected to be about the fifth-warmest in nearly 160 years, Michel Jarraud, secretary-general of the World Meteorological Organization, said at a press conference in Copenhagen, Denmark.
"This year above-normal temperatures were recorded in most parts of the continents," the WMO report reads. "Only North America (United States and Canada) experienced conditions that were cooler than average."
Eight of the 10 warmest years on record occurred in the past decade, according to Jerry Lengoasa, the WMO's assistant director-general.
"It is a big deal because, as you might recall, one of the biggest challenges we have is the annual increases in temperatures," Lengoasa told Â鶹ӰÊÓ Channel on Tuesday. "This has (a) huge impact on weather systems."
Average recorded temperatures have risen by about 0.7 degrees Celcius since the late 1800s, according to the WMO. That represents "very significant warming," Lengoasa said.
The organization also listed climate anomalies from 2009. They included a heat wave in India that killed 150 people, China's worst drought in 50 years and record-breaking temperatures in some Canadian cities last summer.
Final temperature numbers for the year will be available in March 2010, the WMO said.
The preliminary data were released as representatives from 192 countries participated in a historic climate-change summit in Copenhagen. Negotiators hope to combat climate change by forging an international agreement to curb greenhouse gas emissions. The current agreement, the Kyoto protocol, expires in 2012.
More than 100 national leaders, including U.S. President Barack Obama and Prime Minister Stephen Harper, are expected to travel to Copenhagen for the final days of the two-week event.
Many climate scientists argue that an international agreement is needed to steer the world away from burning fossil fuels and other "dirty" forms of energy. Otherwise, plants and animals will become extinct in greater numbers, and flooding and other extreme weather will become more common as global warming worsens.
On Monday, the first day of the summit, climate change officials defended scientific research in the wake of a scandal over stolen emails from a British university.
Global warming skeptics claim the emails show scientists colluding to hide information that refutes their climate change theories.
The scientists allege the emails were being circulated as part of a smear campaign by the hackers.
"The evidence is now overwhelming" that the world needs early action to combat global warming, said Rajendra Pachauri, the head of the Intergovernmental Panel on Climate Change, a UN expert panel.
"The recent incident of stealing the emails of scientists at the University of East Anglia shows that some would go to the extent of carrying out illegal acts perhaps in an attempt to discredit the IPCC," he told the conference.
With files from The Associated Press