The UN's World Meteorological Organisation said Thursday that 2010 was the warmest year on record, confirming a "significant" long-term trend of global warming and producing exceptional weather variations.

The trend also helped to melt Arctic sea ice cover to a record low for December last month, the WMO said in a statement.

Last year "ranked as the warmest year on record, together with 2005 and 1998," the WMO added, confirming preliminary findings released at the global climate conference early December that were based on a 10-month period.

"The 2010 data confirm the Earth's significant long-term warming trend," WMO Secretary-General Michel Jarraud said. "The 10 warmest years on record have all occurred since 1998."

In 2010, the global average temperature was 0.53 degrees Celsius (0.95 degrees Fahrenheit) above the 1961 to 1990 mean that is used as a yardstick for climate measurements, according to the WMO, basing itself on a broad set of US and British-collected data.

That exceeded 2005 levels by 0.01 C (0.02 F) and was 0.02 C (0.05 F) above the 1998 mark, but within a margin of error that made the difference between the three years statistically insignificant, according to the WMO.

"Arctic sea ice cover in December 2010 was the lowest on record" for the month, the WMO also found.

Sea ice around the northern polar region shrank to an average monthly extent of 12 million square kilometres, 1.35 million square kilometres below the 1979 to 2000 December average, according to the UN weather agency.

"There's no good news with respect to that -- the Arctic ice continues to be extremely low," Jarraud told journalists.

Over the past decade, global temperatures have been the highest-ever recorded for a 10-year period since the beginning of instrument-based climate measurements in the mid-19th century.

Last month, even before the year was over, Jarraud confirmed that 2001 to 2010 set a new record as the warmest decade ever.

Recent warming has been especially strong in Africa, parts of Asia, and parts of the Arctic, according to the UN agency.

2010 turned out to be "an exceptionally warm year" in much of Africa and southern and western Asia, as well as in Greenland and Arctic Canada, but there were big variations worldwide.

Northern Europe and Australia were significantly cooler than average, with "abnormally cold" conditions for large parts of western Europe in December, including parts of Scandinavia.

The year was also marked "by a high number of extreme weather events" including Russia's summer heatwave and the devastating monsoon floods in Pakistan.

The agency says that the temperature observations on their own do not pin the cause on man-made greenhouse gases, although it believes this is confirmed separately by other research into carbon emissions in the atmosphere.

Britain's Meteorological Office and the University of East Anglia released provisional global figures on Thursday indicating that 2010 was the "second warmest year on record" with a mean temperature of a 14.5 degrees C.

Meanwhile US institutes including NASA have calculated that 2010 was the equal warmest or warmest in global terms. The WMO's figures were based on data from British and US agencies including the Britain's Met Office.

"Self-proclaimed climate change 'sceptics' may still try to claim that global warming stopped in 1998, but they cannot explain away the fact that nine of the 10 warmest years on record have all occurred since 2000," said Bob Ward, of the Grantham Research Institute on Climate Change and the Environment at the London School of Economics (LSE).