Tag Archives: cub survival

New study that claims it can directly link GHG emissions to polar bear cub survival is poppycock

A global warming miracle has happened. While no scientist worldwide has ever drawn a straight line between greenhouse gas emissions and population declines in a species considered at risk due to climate change, a new paper just published in Science Magazine claims to have performed this unlikely feat for polar bears. It’s called “Unlock the Endangered Species Act to address GHG emissions.”

Note this analysis has not been peer reviewed: as a “Policy Forum” contribution, it’s considered by the journal to be a public interest commentary, not a research paper.

One might be forgiven for asking whether this work represents solid, reproducible science or simply well-timed, sciency-looking rhetoric ready-made for the litigious Center for Biological Diversity to pressure the US government to increase protections for polar bears before the 2024 US election. It is surely no coincidence that this paper made its appearance near the seasonal low for Arctic sea ice as well as during the 15-year anniversary of the ESA listing of polar bears as ‘threatened’ and the 50th anniversary of the ESA itself.

Moreover, knowing this paper was in the pipeline might explain why the 2022 government report on the most recent Western Hudson Bay polar bear decline, which I discussed yesterday, has been kept secret for so long: the results of that report are cited in this new Science paper as supporting evidence that sea ice declines are responsible for recent population declines, which Reuters said in December was clearly not the case for the period 2017-2021.

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Where were the starving W. Hudson Bay polar bears in 2020 if the population had declined by 2021?

Polar bears are supposed to starve before they die, the experts said. They said only a few years ago that dead or emaciated individuals onshore were evidence that many polar bears would soon be dying of starvation out on the sea ice. So, if the Western Hudson Bay (WH) subpopulation had indeed dropped by 27% by late summer 2021 as researchers claimed, where are all the photos of starving bears in the fall of 2020, the year before the count? The photo below of a thin female and cub was taken in late fall of 2021 (the year of the count) by a stationary web cam. In other words, some bears came off the ice without an optimal amount of fat because of poor hunting conditions over the winter but they were still alive. We know that 2020 had the shortest ice-free season in at least 20 years (and no similar images were captured), so bears went into the winter of 2020/2021 in good condition. Ditto for 2017-2019. In contrast to 2021, in 2016 (the year of the previous survey that also indicated a declining population size), bears reportedly came off the ice in good condition.

All I’ve seen are photos of fat bears and fat cubs, even a triplet litter in fall 2020. The shore of WH near Churchill should have been abounding with starving bears in 2020 (and in 2015), if the experts were right about starving bears preceding a population decline. More importantly, where are the studies on food-deprived bears onshore, as were done in the 1980s when WH bears were emaciated and cub survival poor (e.g. Ramsay et al. 1988)? WH bears are being used exclusively to model an implausibly pessimistic future for polar bears across the entire Arctic (Molnar et al. 2010; 2020), which means lack of good science for WH polar bears has big consequences. Covid restrictions in two of those ten years don’t excuse lack of study on this phenomenon.

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Conditions were not golden for polar bears in the 1980s despite what activist expert claims

Does the following statement stand up to scrutiny – i.e. a fact check – of the scientific literature on polar bear ecology?

In the 1980s, “the males were huge, females were reproducing regularly and cubs were surviving well,” Amstrup said. “The population looked good.”

[Steven Amstrup, Anchorage Daily News (Borenstein and colleagues), 5 November 2021: ‘How warming affects Arctic sea ice and polar bears’]
Steven Amstrup

In short, it does not.

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Svalbard Norway now has more polar bear habitat than it did two decades ago

Sea ice around Svalbard, Norway at the end of February 2020 is way above average, as the graph below shows – with more polar bear habitat now than there has been in two decades.

Svalbard ice extent 2020 Feb 28 graph_NIS

Some comparison charts below show that the graph above includes some very high ice years in the 1980s (reaching that dotted line above the mean) for which only global charts are available.

However, contrary to suggestions that more Svalbard ice is better for polar bears, there is no evidence that low extent of sea ice habitat in winter or summer over the last two decades harmed polar bear health, reproductive performance, or abundance. In fact, polar bear numbers in 2015 were 42% higher than they were in 2004 (although not a significant increase, statistically speaking) and most bears were found to be in excellent condition.

Svalbard polar bear_Aars August 2015-NP058930_press release

This suggests a return to more extensive ice to the Svalbard region in winter will have little impact on the health of the entire Barents Sea subpopulation, although it might change where pregnant females are able to make their maternity dens if ice forms early enough in the fall. In other words, the population should continue to grow as it has been doing since the bears were protected by international treaty in 1973.

UPDATE 3 March 2020: According to 28 February tweet by the Norwegian Ice Service, which I just saw today, “the last time there was this much sea ice around Svalbard on this day of the year [28 February] was 2004“. Somehow, I missed 2004 when I was looking through the archive, so I have modified the text below accordingly; see the 2004 chart below and here.

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State of the Polar Bear Report 2019: Are polar bear researchers hiding good news?

International Polar Bear Day is a good day to ask: Are polar bear researchers hiding good news? Extended lags in publishing polar bear counts and a failure to publish data on female polar bear body weights and cub survival in Western Hudson Bay for more than 25 years make it look like polar bear researchers are delaying and suppressing good news.

StatePB2019 cover image

In particular, the failure to report the data on cub survival and weights of female bears suggests that these health measures have not declined over the last two decades as claimed. If these figures are indeed the strongest evidence that sea ice loss due to climate change is harming Western Hudson Bay polar bears, why on earth have they not been made public? And why won’t a single journalist ask to see that data?
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Derocher admits Western Hudson Bay polar bear population may not be declining

Earlier this year, I challenged a journalist to ask to see the data used by Andrew Derocher and his colleagues to support their repeated claims that Western Hudson Bay polar bears are having trouble surviving. It almost happened.

Polar bears_Gordon Court_Committee on the status of endangered wildlife in Canada Dec 2018

David Rose, writing for The Mail on Sunday, has produced an excellent feature on the conflict between Nunavut Inuit and biologists about polar bear management, got Andrew Derocher to tell the truth about current polar bear health and survival.

Or, to be more precise, to waffle a bit on his standard message of doom:

“Even Prof Derocher, who is convinced the bears’ long-term future is bleak, accepts that ‘the wheels are not coming off yet’, while ‘some bear populations are doing fine’. In West Hudson Bay, there has been ‘a recent period of stability’, he says, and though ‘we were seeing starving bears, starving cubs on land, that seems to have slowed down’. Then again, the computer models ‘are not great on the 5 – 10 year time-frame’, and it was possible that although the Arviat bears might look healthy now, they may be about to ‘fall off a cliff’.” [my bold]

This concession by Derocher suggests that Western Hudson Bay bears indeed are thriving, because he’s the guy who holds all the data. But he couldn’t help adding that disaster might be just around the corner.

But did he actually produce the data that show what’s been happening with cub survival or the body condition of females since 2004? Apparently not — but his admission that conditions are not as bleak as he continually portrays them suggests he is covering for data that says the same: polar bears in Western Hudson Bay are doing just fine and Inuit are right to be worried.

This may be as good as it gets unless the people of Nunavut can force Derocher to show his data.

Read the whole story here: “Why all you’ve been told about these polar bears could be WRONG: Animals driven to the edge of their natural habitat by shrinking ice have become one of the defining images of climate change, but Inuits who know the predators have a very different story.” (The Mail on Sunday, David Rose, 30 December 2018).

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Chukchi Sea polar bears number almost 3000 according to new survey results: update

The Chukchi Sea finally has a polar bear population estimate! According to survey results from 2016 only recently made public, about 2937 bears (1522-5944) currently inhabit the region, making this the largest subpopulation in the Arctic. This is exciting news — and a huge accomplishment — but the US Fish and Wildlife Service responsible for the work has been oddly mum on the topic.

beaufort-bears_-suzanne-miller-usfws-3-af-2c-on-spit-1.jpg

Not only that, but an extrapolation of that estimate calculated by USFWS researchers for Chukchi plus Alaska (the US portion of the Southern Beaufort Sea subpopulation) was estimated at 4437 (2283-9527), although with “significant uncertainty.” Nevertheless, it means the 2016 estimate for Alaska could be roughly three times what it was in 2010: a whopping 1500 or so, up from about 450 (or about 225-650) for the same area estimated during the last survey (Bromaghin et al. 2015: Fig. 5a).

Even if the real number for Alaska is only twice as large (~1000), that’s still a huge improvement. It would eliminate the Southern Beaufort as the only polar bear subpopulation in the Arctic to have shown a significant decline blamed on human-caused global warming (Crockford 2018). If the recovery is real, it means the 2004-2006 decline was a temporary fluctuation after all, just like previous declines in the region. I expect, however, that it will take a dedicated SB population survey for officials to concede that point.

There is not yet now a detailed report to cite (Regehr et al. 2018 in prep, see update below), but the numbers were announced at the 10th meeting of the Russian-American Commission on Polar Bears held at the end of July this year (AC SWG 2018) by Eric Regehr (formerly of the US Fish & Wildlife Service, as of 2017 at the University of Washington). [h/t to G.H.] This was the same report that raised the quota for subsistence hunting in the Chukchi from 58 to 85, based on these new figures, as I discussed last week.

Wrangel Island polar bear with cubs 2015 news story

From “Military bases to open on Wrangel Island and Chukotka” 22 October 2015.

Regehr was quoted as saying:

“Chukchi bears remain larger and fatter and have not seen downward trends in cub production and survival, according to new preliminary information on the health and numbers of bears.”

UPDATE 15 November 2018: The scientific paper describing the entirely new method (yes, yet another one: see Bromaghin et al. 2015) used to estimate the size of the Chukchi Sea population is now available (University of Washington press release here), in an open-access paper: Regher et al. 2018. News reports (see one here) spin the positive outcome as something that researchers expected all along but that’s simply not true. They expected Chukchi Sea bears and Southern Beaufort Sea bears to respond similarly to reduced amounts of summer sea ice, as explained here and in Crockford 2017).
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Chukchi Sea polar bears number almost 3000 according to new survey results

The Chukchi Sea finally has a polar bear population estimate! According to survey results from 2016 only recently made public, about 2937 bears (1522-5944) currently inhabit the region, making this the largest subpopulation in the Arctic. This is exciting news — and a huge accomplishment — but the US Fish and Wildlife Service responsible for the work has been oddly mum on the topic.

beaufort-bears_-suzanne-miller-usfws-3-af-2c-on-spit-1.jpg

Not only that, but an extrapolation of that estimate calculated by USFWS researchers for Chukchi plus Alaska (the US portion of the Southern Beaufort Sea subpopulation) was estimated at 4437 (2283-9527), although with “significant uncertainty.” Nevertheless, it means the 2016 estimate for Alaska could be roughly three times what it was in 2010: a whopping 1500 or so, up from about 450 (or about 225-650) for the same area estimated during the last survey (Bromaghin et al. 2015: Fig. 5a).

Even if the real number for Alaska is only twice as large (~1000), that’s still a huge improvement. It would eliminate the Southern Beaufort as the only polar bear subpopulation in the Arctic to have shown a significant decline blamed on human-caused global warming (Crockford 2018). If the recovery is real, it means the 2004-2006 decline was a temporary fluctuation after all, just like previous declines in the region. I expect, however, that it will take a dedicated SB population survey for officials to concede that point.

There is not yet now a detailed report to cite (Regehr et al. 2018 in prep, see update below), but the numbers were announced at the 10th meeting of the Russian-American Commission on Polar Bears held at the end of July this year (AC SWG 2018) by Eric Regehr (formerly of the US Fish & Wildlife Service, as of 2017 at the University of Washington). [h/t to G.H.] This was the same report that raised the quota for subsistence hunting in the Chukchi from 58 to 85, based on these new figures, as I discussed last week.

Wrangel Island polar bear with cubs 2015 news story

From “Military bases to open on Wrangel Island and Chukotka” 22 October 2015.

Regehr was quoted as saying:

“Chukchi bears remain larger and fatter and have not seen downward trends in cub production and survival, according to new preliminary information on the health and numbers of bears.”

UPDATE 15 November 2018: The scientific paper describing the entirely new method (yes, yet another one: see Bromaghin et al. 2015) used to estimate the size of the Chukchi Sea population is now available (University of Washington press release here), in an open-access paper: Regher et al. 2018. News reports (see one here) spin the positive outcome as something that researchers expected all along but that’s simply not true. They expected Chukchi Sea bears and Southern Beaufort Sea bears to respond similarly to reduced amounts of summer sea ice, as explained here and in Crockford 2017).
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Facts contradict predictions that Chukchi Sea polar bears should be in trouble

Last fall, there were persistent alarms raised about low levels of sea ice in the Chukchi Sea that were echoed this spring. But these low ice levels are not really a serious concern for these polar bears: a 2018 assessment found the bears were in excellent health with no declines in cub production or survival. Funny how little we hear about that.

Wrangel Island polar bear with cubs 2015 news story

From “Military bases to open on Wrangel Island and Chukotka” 22 October 2015.

See a photo essay of Wrangel Island here and of the islands polar bears here and here.

You also don’t hear about the fact that sea ice has declined by about the same amount in the Chukchi Sea as in Western Hudson Bay. Since 1979, sea ice in the Chukchi Sea has declined at a rate similar to Western Hudson Bay (-0.90 days per year vs. -0.86 days per year, respectively), see graphs below from Regehr et al. (2016, Fig. 2):

Regher et al. 2016 fig 2 Barents and Chukchi Sea ice declineRegher et al. 2016 fig 2 Wh Bay ice decline

While Western Hudson Bay bear numbers have declined slightly in number (by a non-statistically significant amount) and appear to have suffered some recent declines in cub survival (Dyck et al. 2017) (with unsubstantiated claims of declines in adult body condition), Chukchi Sea bears have not (Rode and Regehr 2010; Rode et al. 2013, 2014, 2018).

The fact that Chukchi bears are thriving while Western Hudson Bay bears appear to be struggling, given almost identical trends in sea ice decline, is a connundrum that polar bear specialist are loath to explain.

Only last week, it was announced that the quota for subsistence hunting of Chukchi Sea polar bears had been raised from 58 to 85 due to the excellent status of the population. Polar bear biologist Eric Regehr was quoted as saying:

“Chukchi bears remain larger and fatter and have not seen downward trends in cub production and survival, according to new preliminary information on the health and numbers of bears.”

So, despite warnings from the polar bear and sea ice “experts” that Chukchi Sea bears may be in dire straits due to recent sea ice declines (see below), it appears that the bears themselves are more resilient to changing conditions than the experts give them credit.

NSIDC sea ice experts cruising the Chukchi Sea took this photo of a polar bear in excellent condition a couple of weeks ago (early August 2018, A. Khan), despite the scary-looking melt ponds:

Chukchi Sea polar bear Arctic_early August 2018_A Khan NSIDC

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Chukchi polar bear status contradicts the “message” – new details

Previously, I summarized preliminary results of polar bear research in the Chukchi Sea undertaken between 2008 and 2011 by US Fish & Wildlife biologist Eric Regehr and US Geological Survey researcher Karyn Rode. At the time, a peer-reviewed paper on this study was promised shortly.

It now appears this paper is indeed on the way. I’m sure of that because a few weeks ago, I came across a conference presentation given by Karyn Rode that is a summary of the upcoming Chukchi research paper. The title of both presentation and ‘in review’ paper is:

“Variation in the response of an Arctic top predator experiencing habitat loss: feeding and reproductive ecology of two polar bear populations.

Rode’s slide presentation (given at the annual Lowell Wakefield Fisheries Symposium at the end of March, in Anchorage, Alaska) was posted online by the symposium organizers. It provides some very interesting details on the status of Chukchi Sea bears compared to bears in the Southern Beaufort, and contains some mighty “inconvenient” conclusions that should raise some eyebrows.

I’ve summarized these details and conclusions below in point form, below the maps.

Figure 1. Chukchi and Beaufort Seas (from Wikipedia), upper. ‘Chukchi Sea’ polar bears are shared between the USA and Russia; ‘Southern Beaufort’ bears are shared between the US and Canada, lower (from PBSG, with labels added). Pink dots are the subpopulations featured in the Rode et al. presentation and upcoming paper.

Figure 1. Chukchi and Beaufort Seas (from Wikipedia), upper. ‘Chukchi Sea’ polar bears are shared between the USA and Russia; ‘Southern Beaufort’ bears are shared between the US and Canada, lower (from PBSG, with labels added). Pink dots are the subpopulations featured in the Rode et al. presentation and upcoming paper.

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