Tag Archives: sea ice

Claim of range-contraction of polar bears due to declines in summer sea ice doesn’t hold up

Posted on January 28, 2015 | Comments Off

Have polar bears suffered a contraction of their historical range due to recent declines in summer sea ice? Buried in a recent journal article lies such a claim, one I can’t recall having seen before. That makes it worth close examination.

Figure 2. A drawing of polar bears on St. Matthew Island that accompanied the May 1, 1875 Harper’s Weekly Journal of Civilization article written by Henry Elliot. See here.

A drawing of polar bears on St. Matthew Island that accompanied the May 1, 1875 Harper’s Weekly Journal of Civilization article written by Henry Elliot. See here.

The assertion appears in the introduction of a recently published paper that got a lot of attention online (“Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic” by Peacock and colleagues (2015), discussed previously here, news coverage here and here).

Here is how the authors put it:

“There is already evidence of change in the contemporary distribution of polar bears. For example, polar bears, once common in Newfoundland [29], are now seen there only infrequently and in small numbers. Similarly, polar bears once regularly summered on St. Lawrence and St. Matthew islands in the Bering Sea [30–32]. Now they are irregularly observed in the Bering Sea and do not spend summers on St. Matthew Island. Although these changes in polar bear distribution may also have been related to overharvest, the recent reductions in the extent of sea-ice due would prevent current and regular use of these areas.” [my emphasis]

There are three main reasons the claim doesn’t hold up to scrutiny:
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Posted in History, Sea ice habitat

Tagged climate change, global warming, Gulf of St. Lawrence, Labrador, Little Ice Age, Medieval Warm Period, Newfoundland, range, range contraction, sea ice, St. Lawrence Island, St. Matthew Island, Vibe

Arctic National Wildlife Refuge in Alaska won’t protect polar bears from thick spring ice

Posted on January 25, 2015 | Comments Off

And the proposed coastal refuge won’t protect the denning areas of the majority of Southern Beaufort Sea polar bears, because most females den out on the sea ice, not on land.

The folks at Polar Bears International (PBI) are crowing with delight at the announcement today that US President Obama has recommended that congress approve plans to implement a proposed an Arctic wildlife refuge area that would include the Arctic coastal plain [see links below, including Obama video].

And in doing so, they mislead the public about how many polar bears use this region of coastal Alaska — as do the US Fish and Wildlife Service on their Refuge website.
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Posted in Advocacy, Life History, Sea ice habitat

Tagged Alaska, Arctic National Wildlife Refuge, coastal, denning females, Fischbach, polar bear, protection, Refuge, Schliebe, sea ice, Southern Beaufort, thick spring ice, US Fish and Wildlife Service, USFWS

‘Threatened’ status for Arctic ringed seals under ESA makes no sense

Posted on January 14, 2015 | Comments Off

Recent research (Crawford and Quakenbush 203; Rode et al. 2014) has shown that sea ice declines in the Chukchi and Beaufort Seas have made life better for ringed seals, not worse (as predicted) – ringed seals are in better condition and reproducing better than they were in the 1970s. Why? Ringed seals do most of their feeding in the open-water period (Young and Ferguson 2013), so a longer open-water season means fatter, healthier seals and more fat pups for polar bears to hunt the following spring.

However, Arctic ringed seals (as well as bearded seals) were designated as ‘threatened’ by the USA in 2012 under the Endangered Species Act, based on predicted ice and snow declines due to prophesied global warming. These listings are all about future threats, with no pretense of on-going harm.

Virtually no other Arctic nation has taken this step for Arctic seals — see previous discussion here. There are lots of ringed seals — an estimated 3-4 million world-wide and about 1.7 million within the critical habitat proposed by NOAA (see below).

As weak as the case for listing polar bears as ‘threatened’ has proven to be, the case for listing ringed and bearded seals is even more feeble (a judge has already sent the bearded seal listing back to the drawing board).
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Posted in Conservation Status, Sea ice habitat

Tagged bearded seal, Beaufort Sea, Bering Sea, Chukchi Sea, conservation, critical habitat, endangered species, future threats, global warming, IUCN, models, NOAA, polar bear, predictions, public hearings, ringed seal, sea ice, threatened

If summer ice was critical for S. Beaufort polar bears, 2012 would have decimated them

Posted on January 12, 2015 | Comments Off

Did we hear a huge hue and cry in 2013 about starving polar bears and low cub survival in the Southern Beaufort Sea? No, we did not. Despite the record-breaking low summer sea ice extent the year before (2012), and despite the fact that USGS biologists were putting collars on polar bear females there the spring of 2013 (Rode et al. 2014), we heard not a peep about a polar bear catastrophe in the Southern Beaufort. Odd, isn’t it?

Several polar bear biologists and sea ice experts were busy late last fall suggesting to the media that a decline in polar bear numbers in the Southern Beaufort was due to declines in summer sea ice, which they blamed on global warming (see quotes below and earlier discussions here, here and here). However, they made no mention of the fact that the record-breaking September ice extent in 2012 did not seem to have any noticeable effect on polar bear health or survival in 2013.

Sea ice maps from the National Snow and Ice Data Center (NSIDC) tell most of the story about what the media were, and were not, told about summer sea ice in the Southern Beaufort between 2001 and 2013. Continue reading

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Posted in Advocacy, Population, Sea ice habitat

Tagged abundance, aerial survey, Amstrup, Beaufort Sea, Bromaghin, Mark Serreze, mark-recapture, polar bear, population estimate, population recovery, Red list, Rode, sea ice, Southern Beaufort, spring ice conditions, summer ice minimum, USFWS

Polar bear gene flow blamed on melting ice is another model result that doesn’t make sense

Posted on January 9, 2015 | Comments Off

Polar bear researchers just published a study that suggests polar bears have moved around the Arctic in direct response to recent sea ice changes — a conclusion I suggest you take with a grain of salt and a raised eyebrow.

That’s because they have also proposed, among other things, that the Svalbard Archipelago was a sea ice refugium during warm interglacial periods, and could be again if the Arctic warms as predicted. That they would accept and promote such a model-based conclusion, which has no relationship with reality, calls their scientific judgment into question.

Svalbard as a potential warm refugium_Jan 8 2015_PolarBearScience

Based on genetic model results, the Svalbard Archipelago (circled) has been proposed as a sea ice refugium for polar bears during previous warm Interglacial periods and during predicted sea ice declines in the future. Yet most years since 1979 (2014 was one exception), this region has been ice free during the summer, making Svalbard a decidedly poor candidate for retaining sea ice when it’s much warmer than today.

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Posted in Population, Sea ice habitat

Tagged Canadian Arctic Archipelago, Cronin, DNA, extinction, gene flow, genetics, Hamilton, Miller, models, PBSG, Peacock, polar bear, Polyak, predictions, refugium, sea ice, warming Arctic

Tracking polar bears in the Beaufort Sea – December 2014 map

Posted on January 6, 2015 | Comments Off

Here is the December 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for December is copied below.

There are only 10 bears being followed now, which means a few more collars have failed, or the bears have moved out of the area or died.
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Posted in Life History, Sea ice habitat

Tagged Beaufort Sea, Chukchi Sea, polar bear habitat, polar bear movements, polar bears, polar bears in winter, satellite collars, sea ice, Southern Beaufort, tracking polar bears, USGS

Polar bear habitat – more Arctic sea ice in Canada this week than in early 1970s

Posted on December 26, 2014 | Comments Off

This week, Arctic sea ice in Canada, where 2/3 of the world’s polar bears live, had more sea ice than was present in the early 1970s. Globally, the ice is spitting-distance close to the 1981-2010 average calculated by the NSIDC for this date – which means lots of winter/spring hunting habitat for polar bears.

This is the peak of the polar bear birthing season (both in the wild and in zoos.) Newborns will be snug in maternity dens built by their mothers onshore or on the sea ice; the rest of the population will be out on the ice.

Regional ice charts going back to the late 1960s and early 1970s for this week show even more surprises — have a look.

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Posted in Sea ice habitat

Tagged baffin bay, Davis Strait, Eastern Beaufort, Eastern Canada, Hudson Bay, ice extent, polar bear, polar bear habitat, polar bears in winter, sea ice, Southern Beaufort, Western Arctic

Challenging NOAA’s “Arctic Report Card 2014” on polar bears

Posted on December 19, 2014 | Comments Off

NOAA’s list of purported evidence for harm being caused to polar bears by Arctic warming is short and weak. It puts the gloomiest spin possible on the current well-being of an animal with all the earmarks of a healthy, well-distributed species.

This year, polar bears are virtually the only species that NOAA mentions in their Arctic Report Card – they’ve put all their icon-eggs in one leaky basket [what happened to walrus??]. But polar bears are doing so well that to make an alarming case for polar bears as victims of Arctic warming, many important caveats had to be left out or misrepresented. Some details given are simply wrong.

This year’s polar bear chapter was penned by IUCN Polar Bear Specialist Group chairman Dag Vongraven (you might recall his email to me earlier this year) and a polar bear conservation activist from Polar Bears International (whose battle cry for donations is “Save Our Sea Ice!”), Geoff York.

I challenge their four weak talking points one by one below.

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Posted in Population, Sea ice habitat, Summary

Tagged Arctic, Arctic Report Card, breakup, Bromaghin, cherry-picking, freeze-up, Geoff York, hybridization, IUCN Polar Bear Specialist Group, mark-recapture, polar bear, population estimate, red herring, sea ice, Southern Beaufort, thick spring ice, USFWS, Vongraven, western hudson bay

Recent S. Beaufort polar bear count was a cherry-picked result – new evidence

Posted on December 17, 2014 | Comments Off

New evidence has come to light that mark-recapture field work used to calculate a new population estimate for Southern Beaufort polar bears did not conclude in 2010 as implied in a widely-publicized paper last month but continued until 2013.

Amstrup w triplet_Prudhoe Bay 2005_USGS_sm

Steve Amstrup in S. Beaufort, 2005 (USGS photo), co-author of Rode et al. paper.

As I discussed previously, last month’s widely-hyped paper (Bromaghin et al. 2015 ~~in press~~) – which reported a decline of ~40% between 2004 and 2010 (based on spring mark-recapture work) – was contradicted by fall survey counts that suggested strongly a population rebound would have been apparent if the mark-recapture work had continued another two years.

A new paper by Karyn Rode and colleagues (which includes Bromaghin and others (e.g. Amstrup) from the previous paper), summarized in a USGS press release issued on Monday and published online Tuesday, utilized comprehensive data collected during mark-recapture work carried out in spring from 1982 to 2013 in the Southern Beaufort Sea.

This new paper used the same kind of comprehensive data as Bromaghin and colleagues – from the same season, in the same region – to assess potentially negative effects of the mark-recapture research method itself, up to 2012 and beyond.

More on the Rode et al. conclusions later¹ – for the moment, what is important is that the work described in the paper confirms that spring mark-recapture work on polar bears in the Southern Beaufort continued beyond 2010. Bromaghin and colleagues didn’t end their mark-recapture work prematurely — they actually left data collected in 2011 and 2012 out of their population estimate analysis when they had to have known the population had not finished rebounding from the 2004-2006 decline.
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Posted in Advocacy, Conservation Status, Population

Tagged abundance, aerial survey, Amstrup, Beaufort Sea, Bromaghin, cherry-picking, IUCN, mark-recapture, models, PBSG, polar bear, population estimate, population recovery, Red list, Rode, satellite collars, sea ice, Southern Beaufort, USFWS, withholding data

Hudson Bay sea ice well above average – excellent early December polar bear habitat

Posted on December 11, 2014 | Comments Off

Sea ice development for this date is well above average on Hudson Bay – even more so than last week – making three years in a row of average-to-above average ice habitat available to polar bears in early December (see last week’s ice summary here). Coverage for the week of 11 December from 1971 to 2104 below (from Canadian Ice Service):