The Arctic just had the warmest winter on record. The repercussions will be global

New Year’s Eve is a foggy memory for most of us during the summer. But for the Arctic, the effects of the hangover linger on.

An odd comparison? Maybe. The Arctic is certainly different than Times Square. Any region north of the Arctic Circle has at least one day of total darkness in winter, and compared to the city that never sleeps, the Arctic winter can seem a dark, remote and inhospitable place. Yet New Year’s Eve marks a critical moment in time for both places.

Did we mention that the Arctic winter is cold, very cold? Surprisingly, on New Year’s Eve in 2015, temperatures at the North Pole soared above zero. Svalbard (the most northerly inhabited island on the planet) was a balmy +8.7 °C compared to an average seasonal temperature of -13.4 °C. New York, by comparison, was roughly the same temperature despite Svalbard’s more northern location. While most of us were busy with celebrations, the Arctic was sending a warning cry that got lost in the revelry.

This kind of extreme heat wave in the polar night was luckily short lived. But overall, warming has continued. The year 2016 has seen the biggest retreat of sea ice in winter months. Throughout January to March, the Arctic experienced the warmest winter on record and ended the winter season with the lowest amount of Arctic sea ice in recorded history, driven by El-Niño and amplified by global warming.

According to the experts at the National Snow and Ice Data Centre, “Large areas of the Arctic reported the warmest conditions in 67 years of weather model data, including the northern half of the Greenland Ice Sheet, much of the central Arctic, southern Alaska and the Canadian Rockies, and parts of central Siberia.”

Satellite sensors can see through the polar night and clouds. This allows them to measure Arctic sea ice extent extremely accurately, day in and day out. These satellites pass over the Arctic many times in a day, and have been in orbit since the late 1970s. That means there’s nearly 40 years of continuous data. When you have 40 years of data you can tease out what is natural variability and what is climate change.

But satellites don’t give us all the information we need regarding localized changes – and these local shifts can provide important warning signs about what’s happening.

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Have you read?
Greenland’s ice sheets are disappearing faster than predicted
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So how do we monitor the Arctic Ocean throughout the year? Russians have historically operated drifting sea ice stations, established in the summer and collecting data throughout the whole year. But now the Arctic summer sea ice is getting so thin and dangerous, they can’t that. So it’s even more important we get these winter observations.

But it’s difficult to get to the Arctic in the winter, and it’s expensive and dangerous – if the cold doesn’t get you, the bears might (you can’t see them, but they can smell you).

Never fear – the cold or polar bears can’t stop science. In 2015, an intrepid team froze their scientific ship in the winter ice. Funded by the Norwegian government, N-ICE was one of the first Arctic Winter Cruises – they froze their research ship in total darkness to make much-needed scientific measurements throughout the winter. Eventually the ship was released when the ice melted.

At the same time, scientists from the EU-funded ICE-ARC project deploy robots on the Arctic sea ice. These robotic platforms provide a continuous presence on the ice that provides site-specific real-time data. That’s a good thing, because Ice Mass Balance buoy (IMB016) clearly recorded the North Pole New Year’s blip.

The good news is that more scientists are picking up this polar challenge. For example, the international and multi-disciplinary Arctic research initiative, MOSAiC, intends to freeze in the German scientific ship, the Polarstern, for a whole year. This will provide valuable information on the Arctic system and give a better understanding of how Arctic change impacts us all, no matter where we live.

There has been a lot of attention (and rightly so) over the years regarding the incredible melt of the Arctic summer sea ice, with less public attention being paid to winter conditions. By doing so, we have had at an incomplete picture. When you have a smaller amount of Arctic ice in winter, it sets up a perfect summer storm – allowing for more extreme ice melt. And that’s what’s happening right now.

Arctic summer sea ice this year is melting near the all-time low.

When you look at this plot, you can easily see the relentless downward march in sea ice extent (way below the average for this time of year). Satellite measurements clearly show the reducing area of summer sea ice in the Arctic from the late 1970s to present. During this time we have melted over half the summer sea ice in the Arctic. Experts predict that the other half will be lost within a few decades.

At present the summer sea ice extent in 2016 is among the lowest three years on record.

A key thing to realize is that winter sea ice preconditions the summer sea ice melt. Winter ice data is also concerning.

Generally speaking, less winter ice means less summer ice – a worrying prospect for an ecosystem that is already close to collapse, and a transformation that brings significant risks to the rest of the world, including our global economy.

However, we can’t look at the loss of Arctic sea ice in isolation: it is a symptom of the changes that are occurring to our planet on a global scale. Arctic change is driving environmental, societal and economic changes that have both regional implications and global consequences. We live in a connected world, and what happens in the Arctic does not stay in the Arctic.

Satellites and intrepid scientists are all sending us the same message: the Arctic winter gave us a serious hangover and it set up a perfect summer storm. We all know a hangover is a painful thing, and there’s no pain killer we can take for this one. But one reason for hope is the increased global attention to the systemic impact of Arctic change – and perhaps the White House’s upcoming Arctic Science Ministerial can help us start collectively addressing the symptoms.