Tag Archives: spring sea ice

Polar bear biologists imply “summer sea ice” and “sea ice” are synonymous

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.

Female with cubs Beaufort_USFWS credit 2007 w label_sm

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…
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Tracking polar bears in the Southern Beaufort May 2015 – thick ice and polynyas

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.

Polar_Bear_Biologist_USFWS_working_with_a_Bear_Oct 24 2001 Amstrup photo

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.
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Spring ice alarm deflated – 2015 ice now as high as 2014 & Davis Strait highest since 1971

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.

Harp seal pup_DFO Newfoundland

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IUCN Specialist Group quietly adds “sea ice changes” to their polar bear status table

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.

Hudson Bay female with cub_Wapusk_Thorsten Milse_Gov CA

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.
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Faux polar bear figures – my editorial in the National Post

Published in the Business section (Financial Post “Comments”) of the National Post this morning:

Paul J. Richards/AFP/Getty Images [NP story]

Paul J. Richards/AFP/Getty Images [from original NP essay]

“Faux polar bear figures” [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

Labrador polar bears face a longer ice-free season than Hudson Bay bears, but do well

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.

Davis Strait Hudson Bay freeze-up at Nov 25 2014_PolarBearScience

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.

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About the time I asked a challenging question at a global warming workshop

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.

Arctic sea ice 2009 vs 2014 NSIDC BIST Foxe Basin marked_PolarBearScience Continue reading