Scientists are struggling to understand why a burst of “scary” warming at the North Pole has pushed Arctic temperatures nearly 20C higher than normal for this time of year.

Experts in the US and Europe say they have been shocked by the soaring temperatures recorded in November, when much of the region is plunged into freezing winter darkness.

Temperatures this month have been as high as almost minus 5C when they are normally closer to minus 25C.

“We’ve been processing this data since 1958 and we haven’t really seen anything like this at this time of year,” said Rasmus Tonboe, a sea ice expert at the Danish Meteorological Institute. “We are watching the situation and trying to analyse what is going on but it’s very surprising.”

The unusual warmth has come as officials at the UN’s World Meteorological Organization said they were 95 per cent sure that 2016 would be the hottest year since records began in the 19th century. It would mean that 16 of the 17 warmest years on record have been this century.

The 17th year was in 1998 when there was a powerful El Niño weather event, as there was in 2015 and 2016.

But some scientists said climate change seemed to be more responsible for the unusual warming at the North Pole this month than the impact of the latest El Niño effect.

“I don’t think that’s a huge factor,” said Jennifer Francis, a Rutgers University climate scientist, explaining that a near-record fall in the extent of sea ice in the Arctic this summer had led to a warmer autumn.

This had reduced the temperature difference between the Arctic and more southerly regions, causing a “wavier” jet stream — a great river of fast-moving air about 10km above the earth that acts as a barrier separating the North Pole from warmer latitudes.

The changes in the jet stream had allowed more warm air to penetrate further north, which explained a lot of the “ridiculously” high Arctic temperatures, Ms Francis said.

“That is scary because it is showing us how rapidly the climate system is changing … We expected for a long time to see the ice disappear and the Arctic warm up and perhaps the jet stream doing bizarre things, but it’s happening much faster than I think anyone expected.

David Fuller's view

Global warming at today’s temperatures is a mixed blessing.  However, should temperatures continue to rise, it increasingly becomes a very serious problem. We need luck and better technologies to limit that problem.

Here is a PDF of the FT's article.