The extent of sea ice in the Arctic follows a very predictable seasonal variation for rather obvious reasons. (Hint: Winter tends to be a tad cooler than summer). Right now towards the end of November the sea ice should be rapidly expanding due to the reduced winter temperature, but it is not following the normal curve.
2016 is proving itself to be a truly extraordinary year for the global climate. Everywhere, each and every month, records are being shattered.
November measurements of the sea ice extent is at a record low in both the Arctic and also the Antarctic. Within the Arctic, the previous low for this time of year was back in 2012 with 9.5 million square kilometres, but now it is 1 million square kilometers lower, and so another records is smashed.
Until roughly about October things were following the normal predictable curve well inside the previous 2012 record, then sea ice growth stalled, picked up again in mid October, stalled again towards the end of Oct, then picked up again, Then a few days ago completely stopped and started reducing … in winter!.
That pause has come to an end and so there is an expectation that the rate of sea ice expansion will start to accelerate once again.
As #Arctic temps lower (albeit still above normal) sea ice extent (SIE) likely to rapidly expand this week -> although will remain very thin pic.twitter.com/ygST8dE9pY
— Zack Labe (@ZLabe) November 22, 2016
So what is going on in the #arctic ?
Temperatures
The temperature for this time of year has been extreme …
“I think that it’s fair to say that the very slow ice growth is a response to the extreme warmth, Over the past few days, extent has actually decreased in the Arctic, and while I don’t think that such a short term decline is unprecedented for this time of year, it is highly unusual, for November is a month when we normally see a quite rapid ice growth.”
– Mark Serreze, director of the National Snow and Ice Data Center in Boulder, Colorado
Okay, maybe time to let the #Arctic know what season it is -> another drop in #seaice extent from the last 24-hours (3rd day in a row, JAXA) pic.twitter.com/2Fl1pQUsD4
— Zack Labe (@ZLabe) November 20, 2016
Despite onset of #PolarNight, temperatures near #NorthPole increasing. Extraordinary situation right now in #Arctic, w/record low #seaice. pic.twitter.com/zpS8hDK2nG
— Daniel Swain (@Weather_West) November 16, 2016
Do we understand why this is happening?
Chris Mooney, writing in the Washington Post, has some insights …
“It’s about 20C [36 degrees Fahrenheit] warmer than normal over most of the Arctic Ocean, along with cold anomalies of about the same magnitude over north-central Asia,” Jennifer Francis, an Arctic specialist at Rutgers University, said by email Wednesday.
“The Arctic warmth is the result of a combination of record-low sea-ice extent for this time of year, probably very thin ice, and plenty of warm/moist air from lower latitudes being driven northward by a very wavy jet stream.”
Francis has published research suggesting that the jet stream, which travels from west to east across the Northern Hemisphere in the mid-latitudes, is becoming more wavy and elongated as the Arctic warms faster than the equator does.
“It will be fascinating to see if the stratospheric polar vortex continues to be as weak as it is now, which favors a negative Arctic Oscillation and probably a cold mid/late winter to continue over central and eastern Asia and eastern North America. The extreme behavior of the Arctic in 2016 seems to be in no hurry to quit,” Francis continued.
Francis cited the work of Judah Cohen, a forecaster with Atmospheric and Environmental Research, who has linked odd jet stream behavior with cold air over Siberia.
Feedback
I’ve banged on about this before. In the arctic we have a system that was not set to simply change in very small steps, but instead would result in potentially dramatic shifts.
White ice reflects solar energy back out into space and away from the planet. Reduced ice, means no reflection, and instead the darker ocean absorbs the solar energy and thus introduces a lot more energy into the system. Once the ice starts to melt, you soon move towards a point where change accelerates, and this is exactly what is now happening.
Does this matter?
It might be tempting to consider the idea of a warmer arctic to be beneficial, but no, you better put that thought on pause for a moment.
The heat exchange between the topics and the Arctic powers our climate. Previously there was a strong jet stream that circled the arctic and in effect acted as a buffer that kept it cold, but that jet stream has weakened and so warm air has pushed up and into the arctic, hence is keeping it well above the normal temperature range. We also have combined with that the warmer ocean.
Thin ice = less ice in summer = more solar energy absorbed = warmer ocean = less ice formation now = … well you get the idea.
As Phil Plait notes on his blog …
The reason this is a concern is twofold. One is that as the northern ice melts, it dumps a lot of fresh water into the oceans. This changes the salinity of the oceans, and that changes how the water flows from the Arctic to the equator and back again. This heat exchange powers a lot of our climate and weather, so having this break down is, in a word, terrifying.
Second, the Arctic is our climate canary-in-a-coal-mine. Because it’s so sensitive to warming, studying it shows us what we’re in for as our planet inexorably heats up.
I won’t spin this: This is not good news.
In other words we should indeed both watch, observe, and worry.
We should not underplay this. What is now being observed is quite frankly shocking, deeply troubling, and a complete surprise.
There is a growing hypothesis that extreme events (heat waves, cold snaps, drought, excessive rain) are all linked to low sea ice and Arctic warming.