The latest from the Arctic - 10/04/2018

Arctic Sea Ice Very Slow to Refreeze As Record Heat Hits Alaska

Nicholas Humphrey

Patreon.com,

4 October, 2018

Sea ice in the Arctic...a major regulator of not only regional climate but global climate circulation...is experiencing extremely slow refreeze after experiencing the 6th lowest extent on record. This is because of a highly amplified jet stream pattern causing strong high pressure to persist over parts of Alaska and the Chukchi-Beaufort Sea Region of the Arctic Ocean. And, much in line with the hypothesis of Dr. Jennifer Francis on how jet streams can be altered by loss of sea ice, very abnormally warm waters from the previous season's sea ice low extents have led to this autumn's set up for limiting refreeze. 

Analysis of the 2018 seasonal sea ice minimum in mid-September compared to 1981-2010 climatology and 2012 record.

As mentioned, Arctic sea ice was extent was the 6th lowest seasonal minimum extent on record. But also notable PhD candidate and researcher Zach Labe notes the Arctic Ocean Basin sea ice was the 3rd lowest extent on record for the date September 27th.

Post-seasonal minimum freezing compared to normals of the 2000s, 1990s and 1980s.

Sea Surface Temperature Anomalies (relative to 1961-1990 climatology) showing extreme temperature anomalies throughout the marginal seas of the Arctic Ocean and notably, 4-8 C anomalies in the Chuchi Sea (the sea area between Russia and Alaska north of the Bering Strait). Actual water temperatures area are up to 8-10 C (46-50 F). 

The very slow and abnormal refreeze...the long-term consequence of the ongoing collapse and eventual end of sea ice in the Arctic...is also part of the wider decrease in ice on the planet in general. I noticed by coincidence just prior to writing this article another sad and dubious record for the global warming history books...*global* sea ice extent...so for both the Northern and Southern Hemisphere...reached a daily record low yesterday. This year just edged out the previous two years, showing how quickly global sea ice is suffering losses.

Daily record low for global sea ice extent for October 2nd. Global sea ice has continued to suffer with notable drops in the North Hemisphere Autumn/Southern Hemisphere Spring. This is at least a result of Arctic sea ice increasingly failing to refreeze and possibly spring sea ice around Antarctica melting earlier, now both with lowering extents year after year since the mid-2010s.  

The implications for the loss of ice on the this planet? Sea ice? Land glaciation? It's easier for the planet to get hotter (which it is becoming) and for our jet stream to become much more chaotic in terms of "wave action" (which it is becoming). And we see things like this:

Global Forecast System model analysis valid 12 UTC October 1st showing pressure anomalies in the middle of the atmosphere. Truly extreme and historic pressure anomalies are ongoing over much of Alaska and over the Chukchi and Beaufort Seas, driven by abnormally warm sea surface temperatures and a very wavy jet stream pattern.

Mean forecast surface temperature anomaly for October 3rd. Very warm temperatures relative to normal in the Arctic from the high pressure system.

According to Richard James, who was quoted in a recent Washington Post article on the massive and persistent Alaska high pressure pattern:

In his analysis of the intensity of the responsible high-pressure zone, James found that it was 5.2 standard deviations above normal. “We’d expect this kind of anomaly to occur less than once every million years, on average (for this particular date window),” James wrote, under the assumptions that the climate is static (which, of course, it is not) and his analysis is correct. 

Extraordinary. 

The long-term weakening of the mid-latitude jet stream because of Arctic warming makes for continued situations where not only the mid-latitudes of the Northern Hemisphere must deal with general warming trends, but also much more chaotic weather conditions from a very increasingly wavy jet stream with far more frequent blocking patterns, where long-wave systems move very little. I have written about this previously as this has been a prominent feature in more and more weather patterns in recent years both in the winters as well as a product of landfalling tropical cyclones. And right on cue, in fact, next week for the US...

Persistent heat ridge for the east, cold trough for the west through perhaps the middle two thirds of October. Good news for the West is at least, higher probabilities of rainfall for drought-stricken areas, and this has already occurred thanks to the remnants of Hurricane Rosa.

European Ensemble Model depiction of an extremely amplified jet stream extending from Canada to Baja California on Monday, October 8th. Abnormally cool in the West, heat in the East, very heavy rain from Gulf of Mexico moisture in the middle of the US.

This goes to the greater point of discussing climate change: Climate Change doesn't just create new phenomena (in fact most phenomena aren't "new", minus perhaps some records), but makes what we've already observed more or less likely as our climate shifts to extreme conditions. Very wavy patterns aren't unheard of at all. But they are becoming more frequent because of climate change and are having impacts on persistent stormy patterns, drought patterns, crop health and production, etc. Just look at the disastrous crop failures in Europe from the extreme record heat this year. 

The wrath of relentless climate change. Boreal Summer/Austral Winter 1918 vs. 2018 compared to 1881-1910 climatology. Last months of World War I, there were isolated heat events...today? The planet is a giant heat event. 

Note the intense anomaly which blanketed Europe.

Beyond just keeping the planet cooler (because of heat absorption and reflection) these events show how the loss of ice harms our stable climate regime and accelerates climate change, particularly sea ice loss which has a large geographic extent and footprint. A footprint, which is decreasing rapidly and having major impacts on our climate and everything we and our fellow species depend on that stable climate for.

Edit at 10/4/2018: Revised caption for Interior Arctic Sea Ice graph to indicate "3rd lowest on record" is the daily record for September 27th.