Tag Archives: Derocher

Amstrup & colleages can’t refute my critique of their 2007 polar bear survival model, Part 2

Polar bear specialists Andrew Derocher and Steven Amstrup recently spent inordinate energy trying to refute the opinion piece I’d written for the Financial Post in celebration of International Polar Bear Day last month, ignoring my fully referenced State of the Polar Bear Report for 2017 that was released the same day (Crockford 2018) and the scientific manuscript I’d posted last year at PeerJ Preprints (Crockford 2017).

polar_bear_USFWS_fat Chukchi Sea bear

Their responses use misdirection and strawman arguments to make points. Such an approach would not work with the scientific community in a public review of my paper at PeerJ, but it’s perfect spin for the self-proclaimed “fact-checking” organization called Climate Feedback. The result is a wildly ineffective rebuttal of my scientific conclusion that Amstrup’s 2007 polar bear survival model has failed miserably.

This is Part 2 of my expose, see Part 1 here.
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Amstrup & colleages can’t refute my critique of their 2007 polar bear survival model, Part 1

It’s been more than a year since I first published my scientific manuscript at PeerJ Preprints (a legitimate scientific forum) on the failure of Amstrup’s 2007 USGS polar bear survival model (Crockford 2017), a year waiting in vain for the polar bear community to comment. They either couldn’t be bothered or knew they couldn’t refute it – I haven’t known for sure which. But I do now.

Beaufort Sea male polar bear USGS_2005 Amstrup photo

Polar bear specialists didn’t comment because they couldn’t refute it in the scholarly manner required by PeerJ: all they could do is tear it down with derision, misdirection and strawman arguments.

I know this because the damage control team for the polar-bears-are-all-going-to-die-unless-we-stop-using-fossil-fuels message wasn’t activated over my fully-referenced State of the Polar Bear Report for 2017 (Crockford 2018) released on International Polar Bear Day last month, but for a widely-read opinion piece I’d written for the Financial Post published the same day (based on the Report) that generated three follow-up radio interviews.

By choosing to respond to my op-ed rather than the Report or my 2017 paper, biologists Andrew Derocher and Steven Amstrup, on behalf of their polar bear specialist colleagues1, display a perverse desire to control the public narrative rather than ensure sound science prevails. Their scientificially weak “analysis” of my op-ed (2 March 2018), published by Climate Feedback (self-proclaimed “fact checkers”), attempts damage control for their message and makes attacks on my integrity. However, a scientific refutation of the premise of my 2017 paper, or The State of the Polar Bear Report 2017, it is not (Crockford 2017, 2018).

Derocher further embarasses himself by repeating the ridiculous claim that global polar bear population estimates were never meant for scientific use, then reiterates the message with added emphasis on twitter:

Derocher tweet 2018 Feb 28 quote

Just as the badly written Harvey et al. (2017) Bioscience paper said more about the naked desperation of the authors than it did about me or my fellow bloggers, this attempt by the polar bear community’s loudest bulldogs to discredit me and my work reveals their frustration at being unable to refute my scientifically supported conclusion that Amstrup’s 2007 polar bear survival model has failed miserably (Crockford 2017).

Part 1 of my detailed, fully referenced responses to their “analysis” of my op-ed are below.  Part 2 to follow [here]. Continue reading

Death of the polar bear as climate change icon validates Mitch Taylor’s skepticism

You could call it karma — the death of the polar bear icon after the shameful hubris of polar bear experts back in 2009.

That year, the IUCN Polar Bear Specialist Group booted 20-year member Mitch Taylor out of their organization, explaining that his skeptical views on human-caused global warming were “extremely unhelpful” to their polar bear conservation agenda.

Said chairman Andrew Derocher in his email to Taylor:  “Time will tell who is correct.”

It’s now clear that Mitch Taylor was right to be skeptical of sea ice models based on pessimistic climate change assumptions; he was also right to be more optimistic than his PBSG colleagues about the ability of polar bears to adapt to changing sea ice conditions (Taylor and Dowsley 2008), since the bears have turned out to be more resilient than even he expected.

Fat mother and cubs_Southern Beaufort April 2016_USGS

Fat polar bears — not starving ones — dominate photos taken in recent years. The total failure of polar bear numbers to crash as predicted in response to the abrupt decline in summer sea ice in 2007 and persistent low summer sea ice levels since then (Crockford 2017), is vindication for Mitch Taylor. It’s time someone said so.

More on the 2009 incident below.
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Breaking: 2016 W. Hudson Bay polar bear survey shows the population is still stable

A just-released report on the most recent (2016) survey shows Western Hudson Bay polar bear numbers were still stable despite predictions that this subpopulation would be wiped out completely (reduced to zero) due to low Arctic sea ice.

Churchill_Polar_Bear_2004-11-15 Wikipedia

The authors of the report on the August 2016 aerial survey of the Western Hudson Bay polar bear subpopulation (Dyck et al. 2017) state clearly that the only trends they could find were that the number of adult males increased somewhat over 2011 estimates and the number of females either declined or remained stable. The overall population estimate was a bit lower (11% less) compared to the 2011 survey but the difference is not statistically significant. Therefore, the population status must be stable.

2011 estimate: 949 bears (using comparable data, range 618-1280), litter size 1.43

2016 estimate: 842 bears (using comparable data, range 562-1121), litter size 1.63

[cf. Foxe Basin [stable], from 2009-2010 survey (Stapleton et al. 2016) litter size was 1.54]

An 11% decline in WH numbers since 2011 is most definitely NOT the decline to ZERO (extirpation) we were told to expect with Arctic sea ice as low as it has been since 2007 (Crockford 2017, see list of annual minimum extents 2007-2017 here).

Note: The percentage decline from 2011 to 2016 for Western Hudson Bay polar bears is 11%, NOT 18% as claimed recently by Andrew Derocher on twitter: it is not appropriate to compare the official 2011 estimate of 1030 (Stapleton 2014) to the 2016 estimate of 842 because the methods used to generate the estimates were different (Dyck et al. 2017). The authors of the report state that the estimate for 2011 that’s comparable to 2016 is 949.

An 11% decline from 1030 would be 917 bears, a statistically insignificant decline that is also biologically insignificant and therefore, so slight as to indicate a stable population.

Predicted sea ice at 2050 and 2080 shown below (see Crockford 2017 for details):

Crockford 2017 sea ice graphic

Quotes, map, and table from the Dyck et al. 2017 report (pdf here) are copied below.

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Polar bear counts for W Hudson Bay: ‘core’ area numbers are not comparable

Polar bear population estimates for Western Hudson Bay have recently become contentious because one specialist has been making statements that confuse the issue. As we all wait for the release of the report on the WHB aerial survey of 2016, it’s worth going over the recent history of these counts and what they have revealed.

Churchill_Polar_Bear_2004-11-15 Wikipedia

The official count for bears in WHB (used by the IUCN Polar Bear Specialist Group, the IUCN Red List, and Environment Canada) is 1030, based on an aerial survey of the entire region conducted in 2011 (Stapleton et al. 2014).

Since last year, Andrew Derocher (University of Alberta) has been telling any media pundit who will listen that WHB polar bears have declined from about 1200 bears in the 1980s to only 800 or so bears today (one example here) — a statement that is clearly not true.  In recent months, however, whether due to complaints from the public or from his colleagues, he’s qualified that statement by saying it’s the number of bears in the “core” area of WHB that has declined.

But is Derocher’s revised statement a clear scientific interpretation of the facts? Have a look at the details below and see if you come to the same decision I have: that it’s not possible to compare WHB ‘core’ area polar bear population estimates over time.

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Southern Beaufort sea ice melt in May: good news for polar bears or catastrophe?

Last week biologist Andrew Derocher recently implied via twitter that less sea ice in the eastern portion of the Southern Beaufort (SB) this year at mid-May is harmful to polar bears (calling it “a hole in the ice where polar bears used to live“), but both long-term and short-term data don’t support such a glass-half-empty interpretation.

Not only does spring breakup of sea ice in the SB normally begin with such open patches of water (see the video above from last year) — driven by the powerful currents of the Beaufort Gyre, not ice melt (explained in detail here) — it may actually be necessary for the survival of local seals, polar bears and whales in spring and early summer (Citta et al. 2015; Crawford et al. 2015; Harwood et al. 2015; Stirling et al. 1981).

As I’ve pointed out before, the biggest threat to SB bears is thick sea ice in spring and its associated late breakup, a 2-3 year-long phenomenon unique to this region known to have occurred about every 10 years since the early 1960s (well documented in the scientific literature) but which has not (as far as I know) happened since 2004-2006.

In other words, a considerable patch of open water and less concentrated ice in the eastern SB around Cape Bathurst is almost certainly a good thing for this particular subpopulation (see previous post here for an in-depth discussion) because historically, when a polynya of some extent has not formed by April or May it has been devastating for local marine mammals.

The fact that an extensive patch of open water existed at mid-May in this region last year and the year before (2015 and 2016) — with no public hue-and-cry about a great dying of SB bears from Derocher or anyone else — suggests that open water in the eastern SB this year is likely to be beneficial for SB polar bears, or at least benign. Continue reading

Still lots of East Coast sea ice but prof tells CBC it doesn’t bode well for polar bears

Davis Strait polar bears around Newfoundland and Labrador are currently experiencing what one polar bear specialist refers to as “failed” sea ice conditions, causing bears to come ashore in droves. I’m not making this up.

Sea ice extent Canada 2017 April 21 CIS

The ice was so thick in the Strait of Belle Isle between Newfoundland and southern Labrador last week that a ferry was stuck for 24 hours and had to be rescued by an icebreaker.

The boats of fisherman on the north shore of Newfoundland are stuck in thick ice that’s not expected to clear until mid-May at the earliest and they can’t get out to fish.

boats-in-ice-near-twillingate_CBC_19 April 2017

See this video posted on Twitter two days ago.

The same thing (perhaps even worse) happened in 2007, see Twillingate in the spring of 2007 below:

Twillingate-heavy ice-20070523_2007 CBC David Boyd photo

Yet, in 2007 there was not a single polar bear reported onshore in Newfoundland (as far as I am aware) but this year there were almost a dozen. And the photos show fat, healthy bears – not animals struggling to survive.

East Coast March April polar bear sightings 2017 V3_9 April

According to Andrew Derocher, that’s proof “failed” sea ice is the reason that polar bears came ashore this year but not last year (when there was also lots of ice in late March/early April, see additional maps and graphs below). Last year there were sightings in the middle of winter (January/February) in Labrador and Newfoundland (which I reported here) and one bear was shot in Newfoundland in early May when he advanced on local RCMP officers.

I think Derocher believes he’s set the record straight by offering an interview of his own to refute the things I said to the CBC last week (I talked on two Newfoundland radio stations, which generated a print CBC article). But Newfoundlanders have to deal with used car salesmen just like the everyone else, so I expect they are having a good laugh right now at the expert who’s blaming their polar bear troubles on a lack of sea ice.
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