Data from the World Meteorological Organization released at U.N. climate negotiations confirmed a warming trend that has gone on for decades, which scientists attribute to man-made pollution trapping heat in the atmosphere.

WMO Secretary-General Michel Jarraud said this year's temperatures through October were at near-record levels. Data for November and December will be analyzed in early 2011 but were expected to be slightly cooler than normal.

Still, there is a "significant possibility 2010 could be the warmest," Jarraud told reporters.

Cold winters in Europe — not counting the early snow and freezing temperatures now gripping Britain and northern parts of the continent — meant it was the coolest year for Europeans since 1996, Jarraud said, but that "did not reflect the global average."

The two other extraordinary years were 1998 and 2005. Jarraud said these three steaming years were within a fraction of a degree — 0.036 degree Fahrenheit— of each other.

This year also saw startling weather events: a deadly summer heat wave in Russia with temperatures in Moscow soaring to just above 100 degrees. Devastating floods in Pakistan were part of the same weather anomaly, Jarraud said.

Although there were no catastrophic hurricanes or cyclones this year, heavy rains lashed Australia and Indonesia, floods swamped Thailand and Vietnam, and drought afflicted the Amazon basin in Latin America and southwest China.

While no single disaster could be traced to human activity and greenhouse gases, Jarraud said natural variation cannot explain the decade-long record. "If you don't take the human emission into account you cannot reproduce what you observe," he said.

Preliminary data, collected from four science centers in the U.S. and Britain, were released as the 193-nation conference negotiated details of a package of measures, mostly designed to help poor countries cope with changes in agriculture, rising sea levels and other effects of a warming world.

Prospects for a limited deal have brightened with the U.S. and China appearing to narrow differences on a key element: how to monitor and verify greenhouse gas emissions.

But other issues that go to the heart of a new global warming treaty — long-term commitments for cutting emissions — proved stubbornly unmoving and out of reach for any resolution during the annual two-week conference.

Nonetheless, analysts said an understanding on measuring emissions would be an important step that could help break the long-standing deadlock on reducing emissions as the negotiations continue in 2011.