Arctic sea ice update - 05/10/2017

If you’re NOT worrying about Arctic sea ice losses you are either ignorant or insane.

Record-Thin Sea Ice Faces Big Predicted Arctic Warm-up This Week

Robertscribbler,

10 May, 2017

If you’re someone who tends to worry about Arctic sea ice losses, this coming week’s weather forecast looks like a bit of a doozy.

 And when you consider that the sea ice is both greatly weakened and thinned in a number of the major monitors, prospects don’t look very good, presently, for 2017’s summer melt season as whole.

Abnormal Warmth Over Greenland and Baffin and Hudson Bays

Over the next 48 hours, Baffin and Hudson Bays will experience the tail end of what an extreme warm-up that produced exceptional May surface melt over the Greenland Ice Sheet and then shifted westward.

Temperatures for Hudson and Central and Southern Baffin, according to GFS model runs, will range above freezing over this time period — hitting as high as the low 40s (F) in Eastern sections of Hudson Bay. Over-ocean readings (which tend to moderate, but not, apparently, in this case) that will range from 5 to 15 degrees Celsius above average. These rather high surface temperatures will help to kick sea ice melt throughout these regions into higher gear.

Pacific Side of Arctic Ocean Predicted to Heat Up

Following the Baffin-Hudson warm-up, a large bulge of much warmer than normal air is predicted to extend northward from a broad region extending from Eastern Siberia through the Bering Sea and Alaska and on into Northwestern Canada. This bulge will, according to GFS model runs, by early next week inject periods of above freezing temperatures over a wide region of the Arctic Ocean that includes the East Siberian Sea, the Chukchi Sea and the Beaufort Sea. And by this time next week, these same model runs project that 10-16 C above average temperatures will dominate a large region of the Central Arctic — forcing above-freezing temperatures over a broad cross-section of the North Pole zone by May 17.

(The Arctic is expected to experience nearly 2 C above average temperatures with some regions over the Arctic Ocean hitting 16 C [28 F] above average. These are considerable departures for May when temperatures in the Arctic tend to moderate. So much warmth is likely to have an impact on the already greatly thinned Arctic sea ice. Image source: Global and Regional Climate Anomalies.)

So much early season warmth is likely to further impact an already greatly weakened and thinned veil of sea ice covering the Arctic Ocean. A cooling cap that even more conservative scientists estimate could be completely removed during a summer as soon as the early 2030s. But in the worst case scenario, and when considering how thin the ice is now, a nearly ice free summer could happen as soon as this year. Few scientists really want to talk about that now — given the likely controversy that would result. But we shouldn’t entirely ignore that possibility for fear of backlash or criticism. Nor should we ignore how such an event would tend to further distort an already disrupted Northern Hemisphere atmospheric circulation.

Indicators Show Very Thin Ice

Over recent weeks, sea ice area and extent measures have recovered somewhat as temperatures over the Arctic Ocean have moderated a bit from very warm conditions during October through March. However, a number of indicators including PIOMAS’s sea ice volume measure show that despite this mild surface extent recovery, the ice is very weak and significantly thinned.

(PIOMAS sea ice volume measure shows a considerable record low departure through mid April of 2017. Image source: PIOMAS.)

It’s worth noting that a significant portion of the extent recovery over recent weeks can be attributed to strong winds blowing ice out of the Arctic Ocean and into the Barents Sea as well as out through the Fram Strait. Such conditions are not normally considered to be healthy ones for ice retention through summer as ice in the Barents and Fram tends to melt far more swiftly than ice secured in the Central Arctic. And the Fram itself is often considered to be a graveyard for sea ice.

As for PIOMAS, the most recent measurement through the middle of April found that sea ice volume had topped out at 20,600 cubic kilometers. This measure was fully 1,800 cubic kilometers below the previous record low set for the month. It’s a tremendous negative departure that, if valid, shows that the state of the sea ice as of this time was terribly unhealthy. A situation that prompted the typically conservative Neven over at the Arctic Ice Blog to state that it’s:

Not looking good. Not looking good at all… with a maximum that was almost 2000 km3 lower than the previous record reached in 2011, it’s obvious that anything is possible this coming melting season.

(According to the EASE NSIDC sea ice age monitor, the multi-year sea ice is now almost entirely removed from the Pacific side of the Arctic. Strong, persistent winds have continued to push a good portion of the frail remainder of this ice out toward the Fram Strait — a graveyard for sea ice. And a big warm-up predicted for this week will begin to test the greatly thinned ice over the Beaufort, Chukchi and East Siberian Seas. Image source: NSIDC and The Arctic Ice Blog.)

Moreover, Neven last week pointed out that according a separate measure (see image above), typically thicker multi-year ice is presently absent from the Beaufort Sea. And, to this point, it’s worth noting that the amazing above normal temperatures that plagued the Arctic cold season for multiple years now have resulted in vast losses among this most healthy subset of sea ice.

Such considerably thinned ice presents practically no barrier to the effects of warming. It can melt quite rapidly and it is far more subject to the physical forces of wind and waves. With strong southerly winds and a big warm-up now in the pipe, it appears that this considerably thinned ice will get its first test in mid-May. Potentially creating large sections of permanently open water very early in the melt season and very close to the ever-more vulnerable High Arctic.

Links:

NSIDC

PIOMAS

Climate Reanalyzer

Earth Nullschool

Hat tip to Neven and…

to the researchers over at The Arctic Ice Blog