Tag Archives: IUCN

IUCN Red Book officials forced scientific standards on polar bear predictive models

As I reported Thursday, the IUCN announcement of a new Red List assessment for polar bear got the usual overwrought attention from international media outlets. However, not one of these contained a quote from a polar bear biologist.


Steven Amstrup, science spokesperson for activist conservation organization Polar Bears International, has so far had nothing to say to the media. Yet, Amstrup was a co-author of the IUCN Red List report. Not until late in the day following the release of the report did his his organization’s website post a short, bland news report (“Climate Change Still Primary Threat to Polar Bears”).

Similarly, Ian Stirling, Andrew Derocher, Nicholas Lunn (also a co-author of the IUCN Red List report), and former WWF employee Geoff York – who are usual go-to guys for polar-bears-are-all-going-to-die media frenzies – have so far been silent and invisible on this issue.

In addition, while the IUCN press release [backup here: 2015 IUCN Red List press release_Nov 19 2015] included a quote from IUCN Polar Bear Specialist Group (PBSG) chairman Dag Vongraven, as of this morning (21 November, PST), the website of the PBSG contains no mention of this decision – no item in the “News” category  and, more importantly, no update of the status table  or global estimates to reflect the changes contained in the report  (even though they obviously knew it was coming months ago: the report was submitted to the IUCN Red List 27 August 2015).

In my opinion, this silence says it all: polar bear specialists know this assessment is a severe de facto critique of their 2008 assessment (as well as Amstrup’s predictive models) and it’s a big step backwards for their conservation activism. I expect they are silent because they are royally pissed off.

However, this assessment is good news because finally, some standards of scientific rigor have been applied to polar bear predictive models – even though the PBSG were still been allowed to pretend that summer sea ice coverage is critical to polar bear health and survival (Crockford 2015).  Continue reading

Only a 70% chance that polar bear numbers will decline by 30% by 2050

Despite the stupendously unwarranted hype being generated out of the recent release of the 2015 update to the IUCN Red List status assessment for polar bears, in fact the prognosis is better than it has been for years.

That’s because polar bear experts have been forced by the IUCN standards committee to acknowledge the great deal of uncertainty in their predictive models. They now admit there is only a 70% chance that number will decline by 30% over the next 35 years: only slightly higher than a 50:50 chance.

That means there is a 30% chance that the numbers WILL NOT decline by 30% over the next 35 years. See my detailed analysis, where you will find copies of the report and links to the online IUCN Red List assessment.

That has not stopped all major news outlets from treating this report as a new pronouncement of gloom:

CBC, Canada: (“Polar bear numbers to fall as Arctic ice shrinks: study
Population will decline by more than 30% over next 35 to 40 years, experts say”). Except the first sentence admits this is merely “likely”, not “will”:

“Polar bear populations are likely to fall by more than 30 per cent by around mid-century as global warming thaws Arctic sea ice, experts said on Thursday in the most detailed review of the predators to date.”

Mirror UK: “Polar bears facing extinction as numbers ‘to fall by a third over next 40 years’: There is now a high probability numbers of the species will decline by more than 30%, experts claim”

Express UK: “Nearly 8,000 polar bears to ‘DIE OUT’ as vulnerable giants hurtle towards ‘obliteration’: POLAR bears face a “decimation” in the next couple of decades with more than 30 per cent in population set for complete wipe-out in the most terrifying warning yet.”

The Guardian UK: ” Climate change is ‘single biggest threat’ to polar bear survival: ‘High probability’ of a 30% decline in polar bear numbers by 2050 due to retreating sea ice, IUCN study finds”

[Except, as I noted in my previous post, the IUCN report did not evaluate extinction risk].


IUCN Red List says global polar bear population is 20,000 – 31,000 (26,500)

The long-awaited 2015 IUCN Red List assessment for polar bears was released today (Wiig et al. 2015) and it includes some rather astonishing details − including the fact that the population trend is unknown.

polar_bear_usfws_no date_sm

1) It confirms the global population size I published in May 2015 (20,129-32,558; average 26,344). See the graph below, now amended to reflect this point. If global numbers do decline over the next 35 years, it will be from a high point not previously acknowledged by the IUCN Polar Bear Specialist Group (PBSG).

Crockford OFFICIAL polar bear numbers to 2015_IUCN concurrs Nov 18

2) The current population trend is listed as: ? Unknown. [NOT declining – if anyone claims it is, send them here: IUCN Red List U. maritimus]

3) It puts the generation time for polar bears at 11.5 years (range 9.8-13.6), a huge drop from the 15 years used in previous predictive models. This change makes a big difference to the model results: three generations (the minimum period needed to show a trend) are now 35 years rather than 45 years.

4) It states there is a 70% chance of a 30% decline in polar bear numbers by 2050 and a 7% probability of a reduction > 50% if sea ice declines as predicted, but noted the large amount of uncertainty in these projections. That means there is a greater chance that numbers will not decline by 30% in the next 35 years (a 30% chance) than that the numbers will decline by 50% or more by 2050. That sounds like good news to me.

5) It will continue to list polar bears as Vulnerable. PBSG biologists managed to prevent polar bears from being listed as Least Concern or perhaps Near Threatened. But they had to give up a lot to get it.

6) The report supplement (Wiig et al. 2015 supppl.) explained why they did not calculate extinction probabilities and extinction is not mentioned at all on the IUCN Red List polar bear assessment page. This assessment only considers the probabilities of a decline in population size by 2050.

Yet, a spokesperson for the IUCN apparently stated (The Guardian, Climate change is ‘single biggest threat’ to polar bear survival; 19 November 2015 ) that:

“There is a high risk of extinction and the threat is serious,” said Dena Cator of the IUCN’s species survival commission. “You could consider polar bears to be a canary in the coal mine. They are an iconic and beautiful species that is extremely important to indigenous communities. But changes to their sea ice habitat are already being seen as a result of climate change.”

Apparently Dena Cator does not expect that people will read the report or find the assessment page on the IUCN Red List website – or she’s giving her personal opinion rather than explaining the report results. More on the points above and links to the report supplement pdf below, with quotes.
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Sea ice is not a stable habitat for polar bears – summarized today in The Arctic Journal

In The Arctic Journal, 7 October 2015: Unstable thinking about polar bear habitat [not my title choice]

Unstable thinking about polar bear habitat_Oct 7 2015 title page

This is a previously unpublished summary, written exclusively for The Arctic Journal, of my peer-reviewed, fully referenced essay on this topic that was published earlier this year by the Global Warming Policy Foundation in their “Briefing Paper” series (#16, June 8, 2015: The Arctic Fallacy: Sea Ice Stability and the Polar Bear), which includes a foreword by Dr. Matthew Cronin, Professor of Animal Genetics at the University of Alaska Fairbanks. Pdf here.

Here are the essential points, one by one:
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Global polar bear population size is about 26,000 (20,000-32,000), despite PBSG waffling

The IUCN Polar Bear Specialist Group admits its global population estimate is simply a qualified guess with a large potential error.  So perhaps it’s time to acknowledge that for the purpose of comparing polar bears to other species of concern, the upper limit for polar bear numbers worldwide could be more than 30,000?

Polar bears USFWS_cover PolarBearNews2013_2014

See previous posts on this global population size issue (here and here); updated information below, including the most recent IUCN PBSG statement.

UPDATE 1 September 2015: here is an updated graph of polar bear population numbers that undo the “subtractions” of the PBSG between 2001 & 2013, giving a final global estimate of about 26,000 (click to enlarge):

Crockford unofficial polar bear numbers to 2015 Sept 1 FINAL

UPDATE 25 November 2015: The 2015 update of the IUCN Red List for polar bears essentially concurs with my assessment about polar bear numbers. They estimate the current global population is 20,000-31,000 (26,500, see below) but say the trend in the population is “Unknown.”

Crockford OFFICIAL polar bear numbers to 2015_IUCN concurrs Nov 18
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US biologists used same flawed models for listing walrus and polar bears as ‘threatened’

More bad science: US biologists successfully used a scientifically flawed model to get polar bears listed as ‘threatened’ and thus emboldened, went on to do the same for walrus.

Walruses_USFWS photo_030515_March 2015

The intricate US Geological Survey model of ‘expert opinion’ that was used to support the listing of polar bears as ‘threatened’ under the US Endangered Species Act (ESA) has been soundly rejected by the world’s leading conservation organization, the IUCN,1 which has has tightened its rules for using “future conditions” (e.g., effects of global warming) in generating Red List assessments. That IUCN condemnation means the USGS model was never “the best available science” for evaluating the status of polar bears  ̶  it was (and still is) substandard, inadequate science that makes a mockery of serious conservation efforts.

However, not only has this flawed model continued to be used by the USGS for polar bears, it has also been used to assess the conservation status of Pacific walrus, which are now officially “candidates” for being listed as ‘threatened’ (US Fish and Wildlife Service 2011).2

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Twenty good reasons not to worry about polar bears

PB  logo coloured Here’s a new resource for cooling the polar bear spin, all in one place. I’ve updated and expanded my previous summary of reasons not to worry about polar bears, which is now two years old. In it, you’ll find links to supporting information (including previous blog posts of mine that provide background, maps and extensive references), although some of the most important graphs and maps have been copied into the summary. I hope you find it a useful resource for refuting the spin and tuning out the cries of doom and gloom about the future of polar bears — please feel free to share. Pdf here of the text below.

This is the 1st anniversary of Canada providing population estimates and trends independent of the pessimistic prognostications of the IUCN/SSC Polar Bear Specialist Group (PBSG) — so let’s celebrate the recent triumphs and resilience of polar bears to their ever-changing Arctic environment.

AK PB N Shore-USFWS Barrow_labeled
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