CANCUN, Mexico — This year is “almost certain” to rank among the three hottest years on record, and 2001-2010 is undoubtedly the warmest 10-year period since the beginning of weather records in 1850, the U.N. weather agency said today.

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 parts of 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 – 0.02 degrees Celsius (0.036 Fahrenheit) – of each other.

This year also saw startling weather events: a deadly summer heat wave in Russia with temperatures in Moscow soaring to a record 38.2 Celsius, just above 100 Fahrenheit. 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.