It's a three-way tie.
According to the World Meteorological Organization, the title of “warmest year on record” now belongs to the years 1998, 2005 and 2010.
Data received by the WMO shows no statistically significant difference between global temperatures those years.
A WMO press release on Thursday stated that 2010 was an exceptionally warm year over much of Africa, parts of Asia, and Arctic Canada. It also says that December 2010 was exceptionally warm in eastern Canada and Greenland.
Arctic sea-ice cover in December 2010 was the lowest on record – 1.3 million square kilometers below the 1979-2000 December average, the report also states.
Still, while 2010 was especially warm in parts of the globe, it was abnormally cold in large parts of northern and western Europe. In parts of Norway and Sweden, temperatures were as much as 10°C below normal. Central England faced its' coldest December since 1890.
The WMO also states that the year 2010 was characterized by a high number of extreme weather events, including a heatwave in Russia, heavy snow in Europe and the devastating monsoonal floods in Pakistan.
The statistics in the WMO's report are based on data sets maintained by the UK Meteorological Office Hadley Centre/Climatic Research Unit, the U.S. National Climatic Data Center, and NASA.
With files from Associated Press