This year is the 10th warmest on record and the highest ever when taking into account the cooling La Nina effect, figures suggest. At the same time, the volume of the Arctic sea ice was the lowest ever and its reach was the second lowest recorded.
The global warming is close to the 2-2.4 Celsius increase in average worldwide temperatures that scientists warn could create catastrophic changes on Earth. The preliminary findings of global temperatures for the 10 months to October 2011 come from the World Meteorological Organisation (WMO) and were issued at the United Nations Framework Convention on Climate Change, at Durban, South Africa.
WMO Secretary-General Michel Jarraud says, "Our role is to provide the scientific knowledge to inform action by decision makers.
"Our science is solid and it proves unequivocally that the world is warming and that this warming is due to human activities.
"Concentrations of greenhouse gases in the atmosphere have reached new highs. They are very rapidly approaching levels consistent with a 2-2.4 degree Centigrade rise in average global temperatures which scientists believe could trigger far reaching and irreversible changes in our Earth, biosphere and oceans."
The combined land and sea temperature is estimated at 0.41°C ± 0.11°C (0.74°F ± 0.20°F) above the 1961-1990 annual average of 14°C (57.2°F) - making it the 10th warmest year since records begain in 1850, says the WMO provisional statement.
The decade from 2002-2011 was the warmest on record at 0.46°C above the long-term average, equalling the 2001-2010 figures.
La Nina helped cool temperatures by 0.10-0.15°C for almost a year from Summer 2010. It also brought drought to east Africa, the central equatorial Pacific area and the American south, as well as flooding in southern Africa, Asia and eastern Australia.
Many places saw surface air temperatures rise above the established average, but in Russia's north they were 4°C above average in some places.
In September, the Arctic sea ice measured 4.33 million square kilometres, more than one-third below the 1979-2000 average and just under the low point in 2007. This summer, unlike in 2007, the Northeast and Northwest Passages were free of sea ice for periods.
Sea ice volume fell to a record low of 4,200 cubic kilometres, around 400 cubic kilometres lower than the previous record set in 2010.
Higher than average temperatures in many northern polar regions resulted in the lowest volume of Arctic sea ice and the second-lowest minimum extent.
The year's weather brought sever drought and flooding in east Africa; flooding in South America, Pakistan and south-east Asia; flash floods that led to landslides in Brazil; extreme weather in the USA; dry early months in Europe and east China and fewer incidents of tropical cyclones.
The final results for 2011 will be released in March 2012 in the annual WMO statement on the global climate. The climate information was gathered by weather and climate stations, ships and satellites.