Data released by World Meteorological Organization at the U.N. climate negotiations in Cancun confirmed the continuation of a decades-long warming trend, and ranked 2010 among the three hottest years on record.

WMO Secretary-General Michel Jarraud told reporters that 2001-2010 is the warmest decade since weather records were begun in 1850, and added that there is a "significant possibility 2010 could be the warmest."

(Data for November and December will not be available until early next year.)

Natural variation in temperature may account for occasional peaks, but cannot explain the decades-long record, according to Jarraud.

"If you don't take the human emission into account you cannot reproduce what you observe," he said.

This year's temperatures were at near-record levels through October. The two other peak years were 1998 and 2005.

Monte Paulsen reports on carbon shift for The Tyee.