The year 2010 will be one of the warmest ever, climaxing a record-breaking decade, the UN's World Meteorological Organization said at global climate talks Thursday.

"2010 is almost certain to be in the top three warmest years on record," WMO Secretary General Michel Jarraud told a press conference. "It is probably the warmest one up to October-November."

He added: "The decade from 2001 to 2010 has set a new record, it will be the warmest decade ever since we have records."

The snapshot was published on the fourth day of the 12-day talks in Cancun under the UN Framework Convention on Climate Change (UNFCCC).

Jarraud said he hoped the provisional assessment -- a consensus of temperature data from four meteorological institutions -- would guide policymakers negotiating a post-2012 pact on global warming.

"This is the (scientific) foundation to say where we are now, these are the facts," he said. "Of course, if nothing is done, this curve will go on increasing and increasing, it will go up and up."

Only two other years, 1998 and 2005, have been warmer since records began, and only marginally so, said Jarraud. Reliable statistical records for world weather date from 1850.

The benchmark for warming is 14 degrees Celsius (57.2 degrees Fahrenheit), comprising the global combined surface temperatures of the air and sea from 1961-1990.

In 1998, temperatures were 0.53 C (0.95 F) above that level, and 2005 exceeded it by 0.52 C (0.93 F). For January-October 2010, there was a rise of 0.55 C (0.99 F), with a margin of error of plur or minus 0.11 C (0.17 F), although there are still two more months of monitoring left.

The final figures for 2010 will be issued next February.

In the decade from 2001 to 2010, global temperatures have averaged 0.46 C (0.82 F) above the 1960-1990 yardstick.

Jarraud said these measurements were a further indicator that global warming was on the march.

The figures do not by themselves pin the cause on man-made greenhouse gases, although this is confirmed separately by other research into concentrations of carbon emissions in the atmosphere, he said.

"It's an additional element to confirm that there is indeed warming... the man-made (causes) you can deduct from other curves, such as greenhouse-gases," said Jarraud.

The report swung a spotlight on a wide range of extreme weather events in 2010, including an unprecedented heatwave in Russia, in which around 11,000 people died.

This phenomenon was linked to extreme moonsoon rainfall in Pakistan that affected millions of people, it said.

Other places that experienced extremely high temperatures were most of Canada and Greenland, the northern half of Africa and South Asia and the western part of China, where Yunnan and Guizhou provinces both had their lowest rainfalls on record.

In some of these heat-hit regions, annual mean temperatures were 3 C (5.4 F) or more above the norm.

Parts of the Amazon basin were badly affected by drought in the later part of 2010, according to the WMO. The Rio Negro, a major tributary to the Amazon, plunged to its lowest level on record.

In many parts of the mid-latitude northern hemisphere, though, the winter was abnormally cold. Ireland and Scotland experienced their coldest winter since 1962-1963, and many other parts of northern and central Europe saw their coldest winter since the 1980s or 1970s.

Hurricanes, typhoons and cyclones are on course to have the least active year since 1979.

Only 65 tropical storms have been observed since the start of the year, and only 35 have reached hurricane-force intensity, compared with the long-term average of 85 and 44 respectively.

Arctic sea ice in the summer of 2010, meanwhile, reached the third lowest extent recorded.

"We are extremely concerned... (this) is certainly a measure of global warming," said Jarraud.

The campaign group Oxfam said the findings confirmed the need for a "climate fund" to help people exposed to shifting weather patterns.

"The climate is changing," Oxfam New Zealan's executive director, Barry Coates, said. "This is making it harder for people to survive. In the first nine months of this year, 21,000 people died due to weather-related disasters -- more than twice the number for the whole of 2009."