The record for hottest measured global temperature was set in 2014. That record lasted a whole year, as 2015 was even hotter. January was the ninth consecutive record-hot month:
Even more shockingly, it was also the most abnormally warm month ever recorded, and the ninth month in a row of record-breaking global temperature.
As Chris Mooney explains:
Global warming has long been known to be particularly intense in the Arctic — a phenomenon known as “Arctic amplification” — but even so, lately the phenomenon has been extremely pronounced.
How pronounced? According to the National Snow and Ice Data Center:
Arctic sea ice extent during January averaged 13.53 million square kilometers (5.2 million square miles), which is 1.04 million square kilometers (402,000 square miles) below the 1981 to 2010 average. This was the lowest January extent in the satellite record, 90,000 square kilometers (35,000 square miles) below the previous record January low that occurred in 2011.
Some combination of the Arctic Oscillation (AO) and a strong El Niño seems to be the cause:
January 2016 was a remarkably warm month. Air temperatures at the 925 hPa level were more than 6 degrees Celsius (13 degrees Fahrenheit) above average across most of the Arctic Ocean. These unusually high air temperatures are likely related to the behavior of the AO. While the AO was in a positive phase for most of the autumn and early winter, it turned strongly negative beginning in January. By mid-January, the index reached nearly -5 sigma or five standard deviations below average. The AO then shifted back to positive during the last week of January.
The sea level pressure pattern during January, which featured higher than average pressure over northern central Siberia into the Barents and Kara sea regions, and lower than average pressure in the northern North Pacific and northern North Atlantic regions, is fairly typical of the negative phase of the AO. Much of the focus by climate scientists this winter has been on the strong El Niño. However, in the Arctic, the AO is a bigger player and its influence often spills out into the mid-latitudes during winter by allowing cold air outbreaks. How the AO and El Niño may be linked remains an active area of research
Mooney:
“We’ve looked at the average January temperatures, and we look at what we call the 925 millibar level, about 3,000 feet up in the atmosphere,” says Mark Serreze, the center’s director. “And it was, I would say, absurdly warm across the entire Arctic Ocean.”
Rafe Pomerance, who was Deputy Assistant Secretary of State for Environment and Development in the Clinton Administration and now sits on the Polar Research Board of the National Academy of Sciences, emphasizes that what happens in the Arctic does not stay in the Arctic.
Impacts of Arctic warming are usually considered in isolation, and that’s a mistake, he says. “It’s unraveling, every piece of it is unraveling, they’re all in lockstep together,” Pomerance says. “What tends to happen is, everybody nationally reports on the latest piece of news, which is about one system. You hear about the sea ice absent the temperature trend. So you really have to think of it as a whole.”
Keep in mind that this is happening in deepest winter. Summer is coming.