Monthly Archives: August 2020

The 2020 Arctic Sea Ice Minimum Extent

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I’ve been waiting for the results of the ARCUS SIPN August call, but despite the timetable specifying “26 August 2020 (Wednesday)” they’ve still not been published and I can wait no longer!

Hopefully the August “predictions” will be available soon, but for the moment let’s take a look at the July 2020 Sea Ice Outlook instead:

For the Arctic, the median July Outlook for September 2020 average sea-ice extent is 4.36 million square kilometers, essentially identical to the median prediction in the June report, with quartiles of 4.1 and 4.6 million square kilometers. For comparison, the historical record September low over the period of satellite observations was set in 2012 at 3.57 million square kilometers, and the second lowest record was 4.27 million square kilometers set in 2007. This year’s projection is close to the 2019 observed September sea-ice extent of 4.32 million square kilometers. As was also the case for the June report, only two of the outlooks project September sea-ice extent below the 2012 record. The consensus judgement against a new record low September sea-ice extent hence remains unchanged. Interestingly, as of this report, observed extent stands at a record low for this time of year.

Note that those numbers represent “September 2020 average sea-ice extent” and not the daily minimum. Let’s now take a look at the assorted different flavours of “Arctic sea ice extent” metric. Firstly here’s the NSIDC’s “Charctic” 5 day average extent:

Next here’s JAXA/ViSHOP extent, generally assumed to be a “2 day average”:

Next here’s the DMI version, which neglects to include 2012:

Continue reading The 2020 Arctic Sea Ice Minimum Extent →

Past Evidence Supports Complete Loss of Arctic Sea-ice by 2035

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Our title today is shamelessly plagiarised from the “Watts Up With That” blog of our old friend Anthony Watts. However daring to be different we have redacted the initial word “Claim -“.

The WUWT blog post is bylined “Charles Rotter”, and refers to a new paper in the journal Nature Climate Change entitled “Sea-ice-free Arctic during the Last Interglacial supports fast future loss“. Here’s an extract from the abstract:

The Last Interglacial (LIG), a warmer period 130,000–116,000 years before present, is a potential analogue for future climate change. Stronger LIG summertime insolation at high northern latitudes drove Arctic land summer temperatures 4–5 °C higher than in the pre-industrial era. Climate model simulations have previously failed to capture these elevated temperatures, possibly because they were unable to correctly capture LIG sea-ice changes. Here, we show that the latest version of the fully coupled UK Hadley Center climate model (HadGEM3) simulates a more accurate Arctic LIG climate, including elevated temperatures. Improved model physics, including a sophisticated sea-ice melt-pond scheme, result in a complete simulated loss of Arctic sea ice in summer during the LIG, which has yet to be simulated in past generations of models. This ice-free Arctic yields a compelling solution to the long-standing puzzle of what drove LIG Arctic warmth and supports a fast retreat of future Arctic summer sea ice.

There’s no mention of “2035” in there, so let’s look instead at yesterday’s press release from the British Antarctic Survey:

Continue reading Past Evidence Supports Complete Loss of Arctic Sea-ice by 2035 →

Facts About the Arctic in August 2020

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A new month begins today, and at the moment it looks as though it’s going to be the most interesting one since August 2012. Here once again is the satellite image of the enormous cyclone that was spinning over the Beaufort/Chukchi Seas just a few days ago:

Here too is the effect of the cyclone on the trajectory of the JAXA Arctic sea ice extent graph:

Here too is the current prognosis of the late Andrew Slater’s “Slater Probabilistic Ice Extent” 50 day forecast:

The cyclone has obviously resulted in a reduction in the rate of extent decline, but take a look at the high resolution AMSR2 “compaction” graph:

The gaps between the remaining sea ice floes have evidently increased, and hence the ice area is declining more rapidly than its extent.

[Edit – August 2nd]

Here’s an animation, based on the University of Hamburg’s AMSR2 concentration maps, which reveals the motion of the sea ice across the Beaufort and Chukchi Seas for the last two months:

Note in particular the side effects of the recent cyclone, visible at the end of the video.

Here too is a close up of the current state of the remaining ice in the Chukchi Sea, snapped by the Suomi NPP satellite through a gap in the clouds:

Plus the current open water north of Greenland. Perhaps once Polarstern has been flushed out into the open water of the Fram Strait at the end of the MOSAiC expedition she could take another look at this almost completely unexplored area of the Arctic Ocean?

[Edit – August 6th]

The latest gridded thickness data has been released by the PIOMAS team, and here are Wipneus’s visualisations:

According to the Polar Science Center:

Average Arctic sea ice volume in July 2020 was 9,300 km3. This value is  only 400 km3 above the  record minimum  value of 8,900 km3 set in 2019. This makes 2020 the fourth lowest on record for July with 2012, 2017,2019 falling just below 2020.

JAXA extent is still lowest for the date, but following the recent cyclone it looks as though it will not maintain that position for much longer:

Now we’re in the month of August it’s possible to do a direct comparison with AMSR2 data for 2012. Here’s sea ice area for the Central Arctic Basin:

[Edit – August 8th]

All of a sudden JAXA extent is in 3rd place in the race to the minimum:

However let’s also take a close look at the state of the sea ice in the Beaufort and Wandel Seas shall we?

At this juncture I reckon that come mid September second place is now more likely than first. However as always, it still all depends on the weather.

[Edit – August 9th]

Surprising as it may seem, high resolution AMSR2 Central Arctic Basin sea ice area has so far managed to keep up with the precipitous drop in 2012:

North of Greenland the clouds have cleared closer to the North Pole, to reveal this:

Fresh this morning from Terra, a rather cloudy view of the devastation near 80N, 150W:

[Edit – August 10th]

In a not entirely unexpected development one of ex Prof. Judy’s denizens is quibbling about the current condition of sea ice in the Arctic. Hence here is a close up of some “gaping holes in the sea ice cover” at 88N between Greenland and the North Pole:

[Edit – August 13th]

A nice clear view this morning of the marginal ice zone of the “Laptev Bite” and thereabouts from the Suomi satellite :

[Edit – August 16th]

JAXA AMSR2 extent has fallen below 5 million km²:

Having been flushed out of the Central Arctic through the Fram Strait the polar research vessel Polarstern is back, seemingly intent on taking a close look at the North Pole:

[Edit – August 19th]

The mid month PIOMAS gridded thickness numbers have been published:

According to the Polar Science Center model Arctic sea ice volume is currently third lowest after 2012 and 2019.

[Edit – August 24th]

Arctic sea ice area based on NSIDC concentration data is now in a “statistical tie” with 2012 for the honour of “lowest for the date” in the satellite record:


High resolution AMSR2 area isn’t far behind:

[Edit – August 24th]

A nice clear view of the disintegrating sea ice north of the East Siberian and Chukchi Seas yesterday:

Watch this space very closely for the next few weeks!