According to sea ice experts, winter sea ice habitat for polar bears is not expected to decline at all by 2050 and the critical spring sea ice that polar bears need for gorging on young seals and for mating is not predicted to change much (Durner et al. 2007, 2009), which is why computer modelled predictions about the dire future for polar bears only assessed the potential future effects of declining summer sea ice (e.g. Amstrup et al. 2007; Stirling and Derocher 2012). Note spring is April-June.
See if that fact is clear in the interview responses by out-spoken polar bear biologists that has just been published in the polar bear portion (“Beyond the polar bear”) of this year’s University of Alberta magazine spring climate change feature. If you can get past the “canaries in the coal mine” opener…
Posted in Advocacy, Sea ice habitat
Tagged advocacy, Derocher, facts, interview, polar bear, predictions, sea ice, spring sea ice, starving polar bears, Stirling, summer sea ice
Polar bear habitat in the Southern Beaufort for May 2015 was a contrast between the development of recurring polynyas (patches of open water) and tremendously thick sea ice. So it’s interesting to see where the polar bears tagged by USGS biologists chose to hang out.
The total number of bears being tracked in May – 23 – is down markedly from the 30 bears USGS biologists started with in April.
Most of the collared bears were concentrated in May along the shore lead (crack of open water) that normally develops between the shorefast ice and the pack ice offshore. That’s especially understandable this year, since most of that pack ice is 3-5 m thick (10-16 ft) – see the maps below.
Posted in Sea ice habitat
Tagged Beaufort Sea, Chukchi Sea, habitat, open water, polar bear, polynya, satellite collars, sea ice, shore lead, spring sea ice, thick ice, tracking, USGS
Arctic ice extent (at 14.1mkm2) on 15 April, was virtually identical to 2014 on that date, and higher than 2006. But the record goes to Davis Strait, which recorded the highest ice extent since 1971 for the week of April 16, while the waters of Eastern Newfoundland to the south (where most harp seals have their pups) had the third highest ice extent since 1969. Lots of fat baby seals are just what polar bears need at this time of year.
Posted in Life History, Sea ice habitat
Tagged Barents Sea, Canadian Ice Service, Davis Strait, harp seal, Newfoundland, NSIDC, polar bear, sea ice, seals, spring sea ice
In late January, the IUCN PBSG made significant changes to its polar bear status table but did not think it was worth bringing to the public’s attention via a tweet, press release or note on their web site’s home page.
What changes? Well, while the group did not see fit to agree with all of Environment Canada’s assessments (e.g. listing Davis Strait bears as “likely increasing” compared to the PBSG’s “stable”, see full list here), it did upgrade their status of Western Hudson Bay bears to ‘stable’ (which EC did back in June 2014).
More significantly, however, they also added two metrics of sea ice change to their assessment table, presumably because alongside ‘human-caused removals’ (which they also track in their tables)1, sea ice changes are supposedly critical ‘threats’ to polar bear health and survival.
So critical, in fact, that they’ve only just now gotten around to measuring it consistently across polar bear territory. Funny thing is, they cite no document that shows the sea ice change calculations for each subpopulation region, nor who generated them.
Let me be clear: no one has ever generated such a sea ice metric before – it is a unique PBSG construct that you will find nowhere else. By providing no documentation that lays out the calculations for inspection, the PBSG are simply insisting the public accept their unpublished, non-peer-reviewed work on faith. Details below.
Posted in Conservation Status, Sea ice habitat
Tagged definition of summer, East Greenland, IUCN Polar Bear Specialist Group, loss of summer ice, PBSG, polar bear, satellite data, sea ice, sea ice metric, spring sea ice, western hudson bay
Published in the Business section (Financial Post “Comments”) of the National Post this morning:
“Faux polar bear figures”
Paul J. Richards/AFP/Getty Images [from original NP essay]
[not my choice of title, by the way]
In which I conclude:
“We admire polar bear biologists for their professional dedication to this iconic species, and rightly so. However, while it’s understandable that polar bear biologists are conservation-minded, the public and policy makers need them to be scientists first and advocates for polar bear protection second. Polar bears are currently doing well – data shenanigans to keep them classified as “threatened” undermine the whole point of doing science.”
I have written extensively about the Southern Beaufort issue — below are links to some of these, which have links to the rest. References are included in these individual posts. Contact me if there is a reference you cannot find: Continue reading
Posted in Advocacy, Population, Summary
Tagged Amstrup, Bromaghin, essay, IUCN, IUCN Polar Bear Specialist Group, models, National Post, opinion, polar bear, population estimate, ringed seals, Southern Beaufort, spring sea ice, starving, Stirling, survey, threatened, USGS
Pretty typical ice levels in both regions for this time of year – Davis Strait polar bears (especially those in Labrador) are still onshore while Hudson Bay bears (even those in the south) have their sea ice hunting platform back.
Funny thing is, the Davis Strait subpopulation may still be increasing despite a longer ice-free season than Western Hudson Bay. And bears in the south of that region – who spend the summer onshore in Labrador – have the longest ice-free season of all1 yet according to the latest survey they were even doing better than bears in northern Davis Strait.
That apparent paradox has an easy explanation – sea ice extent in late summer/early fall (length of the ice-free season) has much less of an impact on polar bear health and abundance than the state of the food supply in the spring. More seals in spring, polar bears do well; few seals in spring, polar bears starve.
Posted in Conservation Status, Life History, Sea ice habitat
Tagged Davis Strait, Eastern Canada, harp seals, ice-free season, Labrador, Peacock, polar bear, sea ice extent, seal pups, spring sea ice, starving polar bears, survival
When you really want to challenge a speaker at a scientific meeting or public lecture, deciding what’s the best question to ask is often difficult. Here’s an example that might inspire you.
In 2009, I asked polar bear biologist Lily Peacock what appeared to be an innocuous question about Foxe Basin sea ice1 at a scientific workshop that got everyone’s attention.
The question — and the reaction — might surprise you.
Posted in Advocacy, Conservation Status, Sea ice habitat
Tagged Arctic marine mammals, breakup, Foxe Basin, global warming, Hudson Bay, International Polar Year, late breakup, Peacock, polar bear ecology, polar bears, public lectures, scientific meetings, sea ice, Society for Marine Mammalogy, spring sea ice, Stirling, workshop