This past weekend, it rained over the ice of the late winter Kara Sea. Falling liquid drops that whispered of the far-reaching and fundamental changes now occurring at the roof of our world.
For an Arctic suffering the slings and arrows of human-forced global warming, the winter ended just as it had begun — with an ice-crushing delivery of warm air from the south.
A burly high pressure system over Russia locked in an atmospheric embrace with a series of low pressure systems stretching from the Barents Sea down into Europe. Winds, originating from the Mediterranean rushed northward between these two opposing weather systems — crossing the Black Sea, the Ukraine, and swirling up over Eastern Europe. The winds wafted warm, above-freezing air over the thawing permafrost of the Yamal Peninsula. And the frontal system they shoved over the melting Arctic sea ice disgorged a volley of anomalous late-winter rain.
(Another ice-melting warm wind invasion rushes into the Arctic — this time through the Kara and Laptev Seas. Image source: Earth Nullschool.)
As this rain hissed over the ice, delivering a load of heat to its fractured and frail surface, temperatures above the Kara Sea rose to 1 to 2 C — or about 25 to 30 C warmer than average (42 to 54 F warmer than normal). Meanwhile, the frontal boundary lofted by the warm winds rushed on — pushing above-freezing temperatures all the way into the Laptev Sea north of Central Siberia.
This most recent rush of warm air to the ice edge region came as a kind of herald for the start of melt season. Melt season start is an event that takes place every year at about this time. But during 2017, the sea ice set to begin this annual melt has never been so weak. The fall and winter warmth has been merciless. Month after month of far warmer than normal temperatures have pounded the ice. And now both sea ice extents and volumes are lower than they have ever been before — or at least since we humans have been keeping track.
Third Consecutive Record Low Sea Ice Extent Maximum
Neven and the sea ice observers over at The Arctic Sea Ice blog produced the following graph depicting what is all-too-likely to be a 2017 in which the sea ice extent maximum just hit another annual record low:
(2015, 2016 and 2017 produced record low or near record low winter maximum years for sea ice extent consecutively. Image by Deeenngee and The Arctic Sea Ice Blog.)
Neven, who is one of the world’s top independent sea ice analysts, noted Sunday that:
After a drop of almost 262 thousand km2 in just three days, it looks highly likely that the maximum for sea ice extent was reached two weeks ago, according to the data provided by JAXA, the Japan Aerospace Exploration Agency (via ADS-NiPR ; it used to be provided by IJIS).
As melt season starts, another record low for sea ice extent maximum raises some serious concerns. The less ice that covers the ocean, the more dark blue surface is left open to absorb the sun’s rays. And this loss of ice poses a problem in that a less ice covered Arctic Ocean can take in more heat during melt season — which can serve as an amplifier for melt rates.
During 2015, Arctic sea ice extent also hit a record low maximum, which was nearly beaten again in 2016. But these losses thankfully did not translate into new record lows by the end of the 2016 summer melt season. Weather, as ever, plays its part. And there is some evidence to indicate that increased cloud cover caused by higher levels of water vapor above the Arctic may help to shield the ice somewhat during warmer months. A feature, however, that did little to prevent severe sea ice losses during the record summer melt of 2012 in which a powerful Arctic cyclone also played a roll in ice melt.
Arctic Sea Ice Volume Looks Considerably Worse
Sea ice extent is the measure of how much ocean the ice covers to its furthest-reaching edge. But it’s not the only measure of ice. Volume, which is a measure of both sea ice area and thickness, probably provides a better overall picture of how much ice is left. And the picture of sea ice volume going into the melt season for 2017 isn’t looking very good at all.
(Arctic sea ice volume through late February was tracking well below trend. This considerable negative deviation presents considerable risk for record low sea ice measures by the end of 2017 melt season. Image source: PIOMAS.)
Sea ice volume is now tracking about 2,000 cubic kilometers below the previous record low trend line for this time of year. In other words, the trend line would have to recover considerably over the coming months in order to not hit new record lows by the end of this melt season (September of 2017).
What’s happened is that the ice has experienced three consecutive very warm winter periods in a row — 2015, 2016 and now 2017. And a resulting considerable damage to the ice increases the risk that new all-time record lows will be reached this year. If the present volume measure remains on track through end of summer, sea ice volume could well split the difference between 2012’s record low of approximately 4,000 cubic kilometers of sea ice volume and the zero sea ice volume measure that represents an ice-free Arctic.
Cruel Summer Ahead
(Warm winds, above freezing temperatures, and rain caused considerable sea ice retreat in the Kara Sea from March 14 [top frame] to March 20 [bottom frame]. This event may well have been the herald to a record spring and summer melt during 2017. For reference, bottom edge of frame is 300 miles. Image source: LANCE-MODIS.)
This discussion is worth consideration given how much heat we’ve seen in the Arctic recently. However, we are unlikely to see such a neat progression. Spring and summer surface temperatures could track closer to normal ranges and cloudy (but not overly stormy) conditions could give Arctic albedo an assist — causing the melt rate to lag and pulling the volume measure closer to the trend line. But, it could also vary in the other direction. For post La Nina (we have just exited a weak La Nina) the ocean gyres tend to speed up — which enhances sea ice export — even as more heat tends to transport in the final post El Nino plume toward the poles.
If this particular form of inter-annual natural variability trend toward warmth and melt in the Arctic takes hold during 2017, then we will have less chance to see a spring and summer sea ice recovery toward the trend line. And this is one reason why we’ve been concerned since 2015 that 2017 or 2018 might see new record lows during the summer for Arctic sea ice.
Hat tip to Suzanne