August 29, 2020 Arctic Ice Returns to Mean

 

To enlarge, open image in new tab.

The melting season this year showed ice extents much below the 13-year average, but the decline moderated in August and presently is close to the mean and to 2007.

As discussed below, the daily minimum on average occurs on day 260, but a given year may be earlier or later.  The 2020 minimum on day 239 will not likely stand, but stranger things have happened.  For now, MASIE is showing a jump of almost 300k km2 bringing yesterday very close to the 13-year average (-3.5%).  SII also stopped declining, but as is often the case, started 11 days ago showing less ice than MASIE.  The table below shows the distribution of ice in the various regions of the Arctic Ocean.

Region 2020241 Day 241 Average 2020-Ave. 2007241 2020-2007
 (0) Northern_Hemisphere 4839354 5017305 -177952 4916182 -76829
 (1) Beaufort_Sea 806154 554434 251720 707135 99019
 (2) Chukchi_Sea 354686 257290 97396 142656 212030
 (3) East_Siberian_Sea 235822 363889 -128067 311 235511
 (4) Laptev_Sea 7420 192875 -185455 279554 -272133
 (5) Kara_Sea 31679 46675 -14996 112935 -81256
 (6) Barents_Sea 0 23436 -23436 10037 -10037
 (7) Greenland_Sea 262773 189236 73536 332635 -69863
 (8) Baffin_Bay_Gulf_of_St._Lawrence 7586 32270 -24684 39777 -32191
 (9) Canadian_Archipelago 342594 317798 24795 271603 70991
 (10) Hudson_Bay 23922 26315 -2393 51493 -27571
 (11) Central_Arctic 2766030 3012169 -246139 2966791 -200761

The extent numbers show that this year’s melt is dominated by the surprisingly hot Siberian summer, leading to major deficits in all the Eurasian shelf seas–East Siberian, Laptev, Kara.  As well, the bordering parts of the Central Arctic show a sizeable deficit to average. These deficits are partly offset by surpluses on the CanAm side: Beaufort, Chukchi, Greenland Sea and CAA.

It is also the case that many regions have already registered their 2020 minimums.  And as discussed below, the marginal basins have little ice left to lose.

Background from Previous Post Outlook for Arctic Ice Minimum

The annual competition between ice and water in the Arctic ocean is approaching the maximum for water, which typically occurs mid September.  After that, diminishing energy from the slowly setting sun allows oceanic cooling causing ice to regenerate. Those interested in the dynamics of Arctic sea ice can read numerous posts here.  The image at the top provides a look at mid August from 2007 to 2020 as a context for anticipating this year’s annual minimum.  Note that for climate purposes the annual minimum is measured by the September monthly average ice extent, since the daily extents vary and will go briefly lower on or about day 260.

The Bigger Picture 

We are close to the annual Arctic ice extent minimum, which typically occurs on or about day 260 (mid September). Some take any year’s slightly lower minimum as proof that Arctic ice is dying, but the image above shows the Arctic heart is beating clear and strong.

Over this decade, the Arctic ice minimum has not declined, but since 2007 looks like fluctuations around a plateau. By mid-September, all the peripheral seas have turned to water, and the residual ice shows up in a few places. The table below indicates where we can expect to find ice this September. Numbers are area units of Mkm2 (millions of square kilometers).

Day 260 13 year
Arctic Regions 2007 2010 2012 2014 2015 2016 2017 2018 2019 Average
Central Arctic Sea 2.67 3.16 2.64 2.98 2.93 2.92 3.07 2.91 2.97 2.93
BCE 0.50 1.08 0.31 1.38 0.89 0.52 0.84 1.16 0.46 0.89
LKB 0.29 0.24 0.02 0.19 0.05 0.28 0.26 0.02 0.11 0.16
Greenland & CAA 0.56 0.41 0.41 0.55 0.46 0.45 0.52 0.41 0.36 0.46
B&H Bays 0.03 0.03 0.02 0.02 0.10 0.03 0.07 0.05 0.01 0.04
NH Total 4.05 4.91 3.40 5.13 4.44 4.20 4.76 4.56 3.91 4.48

The table includes three early years of note along with the last 6 years compared to the 13 year average for five contiguous arctic regions. BCE (Beaufort, Chukchi and East Siberian) on the Asian side are quite variable as the largest source of ice other than the Central Arctic itself.   Greenland Sea and CAA (Canadian Arctic Archipelago) together hold almost 0.5M km2 of ice at annual minimum, fairly consistently.  LKB are the European seas of Laptev, Kara and Barents, a smaller source of ice, but a difference maker some years, as Laptev was in 2016.  Baffin and Hudson Bays are inconsequential as of day 260.

For context, note that the average maximum has been 15M, so on average the extent shrinks to 30% of the March high before growing back the following winter.  In this context, it is foolhardy to project any summer minimum forward to proclaim the end of Arctic ice.

Resources:  Climate Compilation II Arctic Sea Ice

3 comments

  1. Hifast · August 30, 2020

    Reblogged this on Climate Collections.

    Like

  2. tom0mason · August 30, 2020

    Thanks Ron for a good write-up on the current situation, and a laugh at the idiot Gore’s highly manipulative nonsense.

    IMO …
    The fact that we still have plenty of ice, glaciers, and snow is not a good indication. If this planet is coming out of the Little Ice Age (LIA), the frozen areas should be receding, mountain glaciers should be reducing, snow should become a ‘thing of the past’. That, after a nearly 200 years since the end of the LIA, ice, frozen tundra, and glaciers are not shrinking appreciably is not a good sign — it heralds that this planet could all too easily slip back to a cooler, or even a much colder climate.

    Just think how wonderful the world would be if the global temperature rose by at least 2°C – no more ice and snow, more CO2 vented by the oceans and slightly more rain – promoting a glorious global greening and deserts reducing, shipping routes simplified, tree lines back to their historic highs on the mountains, and Greenland becoming a productive part of the planet again.

    Like

  3. Bob Webster · August 30, 2020

    Ron,

    I thought the Gore cartoon needed some updating…

    Enjoy all your updates!

    Best,

    Bob Webster 2881 St. Barts Square Vero Beach, FL 32967 (772) 299-4422

    >

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s