What a difference a bit of historical perspective can make to one’s attitude on the annual Arctic sea ice breakup.
The usual recent pattern (since 1979) has been for breakup to begin on the east side. However, this year and last (below), it has begun in the NW (as it did in 1990 and a few other years).
Not all of the open water is due to melt, of course. As I discussed last week in relation to the Southern Beaufort Sea, winds and prevailing currents at this time of year start to fracture the ice and move it around well before much significant melt has begun.
Compare 2016 (above) to 2006 (below), when there was 0.1 mkm2 less overall – with much less ice in Hudson Strait and in the east of Hudson Bay than this year:
Compare to 2011, when there was also 0.1 mkm2 less overall than this year:
It’s important to keep in mind that the intensive feeding season for polar bears is drawing to a close – within another two weeks, most young-of-the-year seals will be in the water feeding and inaccessible to bears.
The only seals on the ice during June and July are predator-savvy adults and subadults that have hauled out to moult and for these seals the rapidly disintegrating ice creates many escape routes. That means that as long as the ice breakup sequence allows polar bears to get their fill of young seals before the end of May, even during early breakup years most bears should be fat enough to survive the coming summer and winter fasts (see more here). So we should expect to see some bears coming ashore within the next two weeks.
The Canadian Ice Service has a cool NASA animated video showing the Beaufort Gyre in action – you can actually see the solid mass of ice crack and swirl west and north under the pressure of the massive corkscrew current – see original here (tips on getting yourself oriented in the video below the screencap) and view below, for Apri 4- May 3, 2016:
Note that the video is oriented with Banks Island on the bottom and the shore of Alaska along the left-hand side, as if the locator map provided was rotated as below:
The big ‘bite” of ice being torn out to the south of Banks Island is the Amundsen Gulf.
The caption for the NASA video says this (my bold):
“MODIS Terra imagery taken between April 4 and May 3, 2016 of the Beaufort Sea. The animation highlights the gradual ice breakup due to the Beaufort gyre.”
So, early breakup here is due to Beaufort Gyre action – not early seasonal melt.
Posted in Life History, Sea ice habitat
Tagged Amundsen Gulf, Arctic, Banks Island, Beaufort Gyre, Beaufort Sea, Canadian Ice Service, circulation, facts, ice thickness, NASA, polynya, sea ice, spring, video
Using sea ice maps issued by the National Sea Ice Data Center (NSIDC), it’s interesting to compare these two years with respect to polar bear health and survival (keeping in mind that no polar bears live in what I like to call the armpits of the Arctic – the Sea of Okhotsk, the Baltic Sea or in the Gulf of St. Lawrence)1:
22 January 2016
Posted in Conservation Status, Sea ice habitat
Tagged Arctic, Baltic Sea, Barents Sea, darkness, Derocher, facts, feeding, Gulf of St. Lawrence, habitat, NSIDC, polar bear, sea ice extent, Sea of Okhotsk, spring, starving, survival, Svalbard, winter
As I’ve pointed out previously, polar bears are leanest – and thus, hungriest and potentially the most dangerous to humans – at the end of winter (i.e. March).
That is why the unexpected prospect of hundreds of lean and hungry polar bears coming ashore in early March hunting available human prey would be a truly terrifying and daunting experience. Such a speculative scenario stands in marked contrast to an actual incident in July that involved a single well-fed bear that attacked a man asleep in a tent because he and his companions had chosen to dismiss the known risk.
Any predatory attack by a polar bear is terrifying but which is potentially the more deadly? One you can reasonably expect (and thus prepare for) or one that comes out of the blue and catches everyone unprepared?
Posted in Book review, Life History, Polar bear attacks
Tagged attacks, battle between man, beast and Nature, bears starve, climate change, dangerous, Davis Strait, deadly, Eaten, facts, Fogo Island, global warming, harrowing encounter, hungry polar bear attacks, ice melts, March, Meltdown, Newfoundland, novel, polar bear, predatory, scary, sea ice, speculative fiction, spring
EATEN – my new polar bear attack novel – is set in Newfoundland 2025 for a reason. I wondered: what if sea ice coverage 10 years from now is as high or higher than it has been for the last two years, with inevitable positive effects on Davis Strait harp seal and polar bear populations?
The Canadian Ice Service prediction for this region, released earlier this week (1 December 2015, see references for link), is that 2016 is set to meet my “what-if” scenario handily. Nine years to go! See the CIS expected ice coverage for 19 February 2016 below (CIS fig. 3):
How does the above ice map compare to the last two years? At least as high or higher. Have a look below.
Posted in Conservation Status, Life History, Polar bear attacks, Sea ice habitat
Tagged Canadian Ice Service, Crockford, Davis Strait, Eaten, Gulf of St. Lawrence, harp seals, Labrador, March, Newfoundland, novel, polar bear, polar bear attacks, predictions, spring, swimming polar bears, what if
In The Arctic Journal, 7 October 2015: Unstable thinking about polar bear habitat [not my title choice]
This is a previously unpublished summary, written exclusively for The Arctic Journal, of my peer-reviewed, fully referenced essay on this topic that was published earlier this year by the Global Warming Policy Foundation in their “Briefing Paper” series (#16, June 8, 2015: The Arctic Fallacy: Sea Ice Stability and the Polar Bear), which includes a foreword by Dr. Matthew Cronin, Professor of Animal Genetics at the University of Alaska Fairbanks. Pdf here.
Here are the essential points, one by one:
Posted in Conservation Status, Sea ice habitat
Tagged Arctic Journal, decline, GWPF, habitat, IUCN, polar bear, population size, sea ice, spring, summer, thick spring ice
Now we have poor hunting conditions in the Bering Strait touted as evidence that “walrus migration patterns have changed” with the implication that this is because “…the past eight years have had the eight lowest amounts of summer sea ice on record” due to man-made global warming.
A subsistence lifestyle is hard, particularly so if it depends on a highly mobile, migratory herd animal. Think Barren-ground Inuit caribou hunters, who often starved because herd sizes declined for a few years or moved unpredictably.
Many factors – seasonal weather, last year’s winter conditions, size of the herd, food supply – all affect where and when a migratory herd will move and the likelihood it will be positioned for optimal harvesting by hunters. Add another highly variable factor into that – Bering Sea ice – and you have a highly unpredictable food supply, especially if you sit in one spot (like on St. Lawrence Island) and expect that migratory herd animal to come within reach.
Hunting walrus from St. Lawrence Island depends on just the right combination of ice and winds. Too much ice is not good, too much open water is not good, and too much wind is not good.
Alaska Dispatch, courtesy the Associated Press, reports St. Lawrence natives are again short of walrus meat because of “warm temperatures”: “Warming temps push walrus north, leaving Alaska villages without traditional food source” (Rachel D’Oro, The Associated Press, August 6, 2015). And the caption of the above USGS (A. Sonsthagen) photo predictably implies all current hunting troubles can be blamed on climate channge:
“The walruses in this July 2012 file photo are hauled out in the Eastern Chukchi Sea. Walrus migration patterns have changed as sea ice and other environmental factors have shifted — and that’s spelled trouble for Alaska Native communities who hunt them for subsistence.”
The people of St. Lawrence Island and the Bering Strait that depend on walrus for subsistence have my sympathy, they indeed have a hard life – but this is not a tale of woe about the status of Pacific walrus and changing summer sea ice.
Bering Strait natives hunt walrus in spring, from mid-April to early June (Huntington et al. 2013). All indications are that walrus are moving differently than they used to in summer because the population is now very large. As far as I know, there is no new population information on walrus that wasn’t available last year, when I covered this topic extensively (Crockford 2014; video below).
Posted in Life History, Sea ice habitat, walrus
Tagged Alaska, Bering Sea, Chukchi Sea, climate change, migration, polar bear, prey, sea ice, spring, St. Lawrence Island, subsistence hunting, summer, video, walrus