The images above come from MASIE showing ice extents starting day 266, the lowest daily extent in 2021. Over the last 18 days, Arctic ice has grown by 1 Wadham (1M km2) to now exceed 6 Wadhams, about 276k km2 greater than the 14-year average for day 284. At the bottom center Barents Sea ice reaches out to Iceland.  Svalbard bottom right becomes encircled by ice.  East Siberian Sea top right has ice connecting to the shore. Top center Beaufort and Chukchi seas are also adding ice rapidly.

The ice recovery since September minimum is shown in the graph below.

Day 260 was the 14 year average annual daily minimum at 4.39m km2. MASIE 2021 was 776k km2 above average, and SII was 427k km2 lower than MASIE.  Note that 2007, 2019 and 2020 weere much lower than average throughout the period. SII is again tracking MASIE since day 274.

Region	2021284	Day 284 Average	2021-Ave.	2007284	2021-2007
(0) Northern_Hemisphere	6010191	5733557	276634	5134886	875305
(1) Beaufort_Sea	787643	662884	124759	718210	69433
(2) Chukchi_Sea	547815	242829	304986	60352	487463
(3) East_Siberian_Sea	571575	434918	136657	311	571265
(4) Laptev_Sea	164089	298559	-134470	409211	-245122
(5) Kara_Sea	110917	80208	30710	128294	-17377
(6) Barents_Sea	18	26816	-26797	14013	-13995
(7) Greenland_Sea	221491	318518	-97027	423939	-202449
(8) Baffin_Bay_Gulf_of_St._Lawrence	53199	77124	-23925	84058	-30859
(9) Canadian_Archipelago	474565	531008	-56443	444876	29689
(10) Hudson_Bay	119	9213	-9093	1936	-1817
(11) Central_Arctic	3077617	3050338	27279	2848411	229206

The main deficits to average are in Laptev and Greenland Seas, and CA, offset by surpluses elsewhere, especially in BCE (Beaufort, Chukchi, East Siberian seas).

The Bigger Picture 

We have passed 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 ice is found in September. Numbers are area units of Mkm2 (millions of square kilometers).

Day 260											14 year
Arctic Regions	2007	2010	2012	2014	2015	2017	2018	2019	2020	2021	Average
Central Arctic Sea	2.67	3.16	2.64	2.98	2.93	3.07	2.91	2.97	2.50	2.95	2.90
BCE	0.50	1.08	0.31	1.38	0.89	0.84	1.16	0.46	0.65	1.55	0.89
LKB	0.29	0.24	0.02	0.19	0.05	0.26	0.02	0.11	0.01	0.13	0.16
Greenland & CAA	0.56	0.41	0.41	0.55	0.46	0.52	0.41	0.36	0.59	0.50	0.46
B&H Bays	0.03	0.03	0.02	0.02	0.10	0.07	0.05	0.01	0.02	0.04	0.04
NH Total	4.05	4.91	3.40	5.13	4.44	4.76	4.56	3.91	3.77	5.17	4.48

The table includes some early years of note along with the last 5 years compared to the 14 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.

2021 stands out from lower ice years by the higher extents in Central Arctic, BCE and LKB, especially Kara Sea this year.

Resources:  Climate Compilation II Arctic Sea Ice