With Barents Sea ice way above average this summer, Polar Bear Specialist Group biologist Ian Stirling now claims the old polar bear that he said died of climate change last year on Svalbard was “in his prime” and still blames the bear’s death on lack of sea ice — despite all evidence to the contrary.
UPDATE Sept. 19, 2014 typo fixed in Fig. 1 caption [sea ice low for 2012 was 3.41 m2km, not 4.1, see here.]
Last week, Stirling apparently thought the time was just right to offer faithful Polar Bears International readers some unscientific anecdotes (i.e. without proper details of the context) about the polar bears of Svalbard.1
Many of these Barents Sea bears, according to Stirling, are starving due to changes in sea ice, including the infamous old bear that died of “climate change” there last year – which he now claims was “in his prime.”
[For background on “the bear that died of climate change” that hit the news in August of last year, see the section “dying of old age” in this post, where I pointed out the fact that this 16 year old bear had left the ice in April (where he was tagged by Norwegian biologists) at the height of the spring feeding season, which was definitely not normal behaviour for a bear in good health. I also provided evidence (collected by those same Norwegian biologists) that the condition of that bear was not at all typical of adult male bears of the region at that time. See my follow-up post for a map and other details]
“For example, last year we found a 16-year-old bear, with a history of living at the southern end of Spitsbergen, dead on a small islet at the north end of the island, far from where he had ever been known to range before (see related blog post). He was in good condition when he was captured three months earlier that year near the south end of the island and should still have been in his prime at that age.
However, in the months that followed, most of the annual sea ice that would normally be present in the fiords where he usually lived was gone. When we found him on the north end of the island, he was but an emaciated shadow of his former self. It appeared most likely he starved to death while searching for better ice from which to hunt seals, though we were unable to collect specimens for a laboratory analysis to confirm the cause of death. In recent years, several other dead bears have been reported from different locations around the archipelago but, similarly, the causes of death have not been confirmed from an analysis of specimens.
Even by the standards of the rapid changes in amounts of sea ice around Svalbard in recent years, the timing of freeze-up and breakup through the winter of 2013-2014 was eye-popping. Freeze-up did not occur throughout much of the archipelago until early December or later. The map below shows how little ice was present around the coast of the entire archipelago as late as December 2. Note there is still a substantial amount of open water around the circumference of the entire archipelago! Very little annual ice formed at all in some of the fiords along the west coast of Spitsbergen through most of the following winter.” [my bold]
No mention of the fact that sea ice in the area has now recovered spectacularly and is far higher than average this summer.2
No mention either of the known effects of the Atlantic Multidecal Oscillation (AMO) on spring sea ice — and polar bears — in the Barents Sea, which I discussed (with references) earlier this year.
With present ice conditions (Fig. 1 and 2), it looks like the fall ice cover in this area will be well above the 60% threshold for the winter of 2014/15, because the ice will not have retreated since this summer.Related posts:
Barents Sea polar bear status and sea ice declines
[with detailed map of Svalbard] March 10, 2014
Footnote 1. The following anecdotes that Stirling also offered in his essay are unscientific snapshots that tell us nothing about how polar bears are — or are not — adapting to changing levels of sea ice:
“In the last few years, I have observed several female polar bears with small cubs on land in several different areas of Svalbard, beginning their fast through the ice-free period, well away from the nearest sea ice, as early as late June or early July. More were in much poorer body condition than I would have expected that early in the summer. For example, the small cub with the thin mother I photographed on July 1, 2010 (see photo above) probably had over four months to go before the return of the sea ice. It is unlikely the cub survived. Although healthier females and cubs are also seen each year, especially in the more easterly and northern areas closer to where sea ice breaks up later in most years, even there I have seen more litters of thin cubs than I would normally expect early in the summer.” [my bold]
In order to determine if any of Stirling’s sightings are useful evidence, we need to know the age of the polar bear females he saw. Young mothers often have a hard time raising their first few litters successfully because they are less experienced at hunting and hunting enough to feed two or three mouths is hard work.
Also, we need to know if the Barents Sea subpopulation had more young mothers than usual during the time period Stirling’s observations were made. That would account for him seeing more females in poor condition. But unless we know the age of the bears Stirling saw and how many young mothers there were in the population at the time, we cannot determine if what Stirling saw was in any way significant in a scientifically meaningful way.