Firstly note that on average August shows ice declining 1.94M km2 down to 4.91M km2. But 2022 started higher and on day 238 was approaching average, before ceasing further ice losses (see HS blade above). As a result the 2022 August ice extent decline is only 1.54m km2. The extents in Sea Ice Index in orange were somewhat lower during the period. The table for day 243 shows a 10% 2022 surplus over average and how the ice is distributed across the various seas comprising the Arctic Ocean. The surplus this year over 2020 is more than 1 Wadham (1M km2 ice extent).
|Region||2022243||Day 243 Average||2022-Ave.||2020243||2022-2020|
There are only a few small deficits to average overcome by surpluses almost everywhere, especially in BCE (Beaufort, Chukchi, East Siberian seas), as well as Central Arctic, Laptev and Greenland Sea. And as discussed below, the marginal basins have little ice left to lose.
The Bigger Picture
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. This post provides a look at August from 2007 to yesterday 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 lowest on or about day 260.
The large August surplus in 2022 is significant: In a typical year the overall ice extent will end September slightly higher than at the beginning.
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||15 year|
|Central Arctic Sea||2.67||3.16||2.98||2.93||2.92||3.07||2.91||2.97||2.50||2.95||2.90|
|Greenland & CAA||0.56||0.41||0.55||0.46||0.45||0.52||0.41||0.36||0.59||0.50||0.47|
The table includes two early years of note along with the last 8 years compared to the 15 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
via Science Matters
September 1, 2022 at 10:23AM