Britain's Met Office last week said the global mean temperature for next year was expected to be about 0.84 deg C warmer than the 1961-1990 average, and even higher than this year's prediction of 0.64 deg C.
PARIS • In a season traditionally associated with ice skating, snowball fights and mulled wine in wintry Europe, birds are chirping, flowers are blooming and fake snow is covering Alpine ski slopes in one of the warmest Decembers on record.
In Finland, normally one of the coldest places on earth, the mercury hit a record 10.3 deg C in the capital Helsinki on Sunday.
Temperatures in the teens were recorded in Sweden and Estonia, while London's St James's park measured an astonishing 16.9 deg C on Sunday.
Even glacial Moscow has been chalking up much warmer readings. "The average temperature on Monday (5 deg C) is almost 12 deg C above the norm for the season (minus 6.5 deg C)," weatherman Nikolai Terechonok said.
None of the Russian capital's 1,200 natural ice rinks has opened this winter, and the artificial rink in Red Square was closed on Monday for "technical" reasons. "It is not an ice rink any more, but a beautiful pond," said a rink worker.
In the Italian Alps, ski stations have had to resort to artificial snow. Cherry blossoms have been spotted in Dresden, Germany, and daffodils are flowering in Britain.
Last week, the Royal Dornoch golf range in Scotland tweeted: "The mowers are back out to cut greens in mid-December!"
As clement weather abounds, many may wonder: Is global warming behind it all?
It is hard to know with certainty, experts say, but climate change is unlikely to be the sole cause.
"It is nothing new to have such a big change from one year to another," said Mr Frederic Nathan of the Meteo-France weather office, pointing to natural variability.
Previous record-warm Decembers occurred in 2000, he said, and in 1934 - long before man-made climate change became an issue.
Climatologists are loath to attribute a specific weather event, such as an exceptionally warm year, to global warming, but they do predict that people in northern Europe will become accustomed to warm winters.
Parts of the United States and Canada, too, have been experiencing an unusually balmy winter, while in the southern hemisphere, Australia has been battling heatwaves and bush fires, and southern Africa, severe drought.
Absurdly warm weather is expected to shatter records along the US East Coast tomorrow.
"It looks like the eastern seaboard, from Florida into New England has the potential to set records for Christmas Eve," said meteorologist Richard Bann of the National Weather Service. "There will be no snow on Christmas. It is just too warm over the eastern US to have any snow."
US government scientists say the world shattered yet another heat record last month, and 2015 will likely be the hottest year in modern history. Europe experienced its warmest November since 1910.
The overall trend, scientists say, is due to climate change, whereby emissions from burning fossil fuels accumulate in earth's atmosphere and trap heat.
But in some parts of the world, the El Nino phenomenon, particularly strong this time around, is helping to drive up temperatures.
Britain's Met Office said last week that the global mean temperature for next year was expected to be about 0.84 deg C warmer than the 1961-1990 average, and even higher than this year's prediction of 0.64 deg C.
"This forecast suggests that by the end of next year, we will have seen three record, or near-record, years in a row for global temperatures," Mr Adam Scaife, head of long-range prediction, said in a statement.
The Met Office said it did not expect the run of back-to-back record-breaking years to continue indefinitely.
"But the current situation shows how global warming can combine with smaller, natural fluctuations to push our climate to levels of warmth which are unprecedented in the data records," it said.
On Dec 12, 195 nations signed a pact to limit average global warming to "well below 2 deg C" over pre-Industrial Revolution levels, and aim for 1.5 deg C, in a bid to "significantly reduce the risks and impact of climate change".
Some fear it could be too late for certain holiday pastimes that rely on natural snow or ice.
"Ski? Ski where?" lamented Ms Natalia Afanassieva, who runs a ski resort near St Petersburg.
AGENCE FRANCE-PRESSE, REUTERS