Winter in the northern hemisphere this year has been the warmest since records began more than 125 years ago, raising fears of global warming.
The National Oceanic and Atmospheric Administration (NOAA), a US government agency, said the combined global land and ocean surface temperature from December through February was at its highest since records began in 1880.
"Contributing factors were the long-term trend toward warmer temperatures, as well as a moderate El Nino in the Pacific," said Jay Lawrimore of the National Climatic Data Center run by the NOAA.
The NOAA said that temperatures were continuing to rise by a fifth of a degree every decade. The 10 warmest years on record have occurred since 1995.
Weather experts predict that 2007 could be the hottest year on record.
The combined temperature for the December-February period was 1.3 degrees F (0.72 degree C) above the 20th century mean, the NOAA said in its website.
Lawrimore himself did not provide the 20th century mean temperature nor the relevant figure for December-February. He only said the deviation from the mean was what was important.
Temperatures were above average for these months in Europe, Asia, western Africa, southeastern Brazil and the northeast half of the United States, with cooler-than-average conditions in parts of Saudi Arabia and the central United States.
While the Centre would not link the developments to global warming, the study itself had been taken up as part of the work of the Intergovernmental Panel on Climate Change (IPCC).
A draft document of this committee made available to the media last month had warned that harmful effects of global warming on daily life were already showing up. Within a couple of decades hundreds of millions of people won't have enough water, it had predicted. Also By 2080, hundreds of millions of people could face starvation.
At the same time, tens of millions of others would be flooded out of their homes each year as the Earth reeled from rising temperatures and sea levels.
Tropical diseases like malaria would spread. By 2050, polar bears would mostly be found in zoos, their habitats gone. Pests like fire ants would thrive.
It concluded that it was at least 90 per cent certain that human emissions of greenhouse gases rather than natural variations were warming the planet's surface.