Announcing the publication today of Version 3
2 of my paper that tests the hypothesis that polar bear population declines result from rapid declines in summer sea ice, updated with recently available data. Version 2 provides the scientific support for the information presented in the GWPF video published yesterday, “Polar Bear Scare Unmasked: The Sage of a Toppled Global Warming Icon” (copied below).
[The graphic above was created by me from the title page and two figures from the paper]
Updated 1 March 2017: I added an important reference to the paper below that got overlooked in previous versions (the work of Armstrong et al. 2008, see this post), making Version 3 the latest and most up-to-date.
Crockford, S.J. 2017 V3. Testing the hypothesis that routine sea ice coverage of 3-5 mkm2 results in a greater than 30% decline in population size of polar bears (Ursus maritimus). PeerJ Preprints 2 March 2017. Doi: 10.7287/peerj.preprints.2737v3 Open access. https://doi.org/10.7287/peerj.preprints.2737v3
Version 3, published 2 March 2017, adds an important reference; Version 2, published 28 February, incorporates additional reviewer comments and suggestions received on Version 1, as well as the updates noted above.
Posted in Conservation Status, Population, Sea ice habitat
Tagged decline, global warming, hypothesis, IUCN Red List, observations, polar bear, population size, predictions, sea ice, USFWS
A brief historical perspective on the failed predictions that have plagued scientific understanding of Arctic sea ice changes – predictions embraced wholeheartedly by polar bear specialists and conservation experts. It’s worth a watch.
Transcript here from the Global Warming Policy Foundation.
Posted in Advocacy, Sea ice habitat, Summary
Tagged death spiral, decline, extinction, facts, history, polar bear, predictions, sea ice, September ice minimum, threatened
Take-home quote from a new polar bear paper by Todd Atwood and colleagues (2016):
“…there is no causal link between the patterns in polar bear vital rates and increased use of terrestrial habitat…”
In other words, there was no information to link the increased time polar bears spent onshore with either an increase or a decrease in body condition, survival or cub production. The authors did find that polar bears were strongly attracted to the bone piles that accumulated in the fall from 2010-2013 after Inuit bowhead whale (Balaena mysticetus) hunting at Barrow, Cross Island, and Kaktovik. Isn’t that a surprise?
The results also appear to confirm previous work that showed terrestrial (land-based) foods are not important to polar bears – a conclusion I totally agree with and which I discussed last year here. No wonder there was no press release issued by USGS about this study. It’s only “news” because someone the Anchorage Daily News interviewed lead-author Atwood yesterday as a way of promoting the International Bear Conference (see previous post here, now updated with a link to the Talk of Alaska radio podcast). Atwood implied there could be advantages to bears from feeding on the bone piles but admitted he had no data to support that assumption.
Posted in Advocacy, Life History, Population
Tagged Atwood, bone piles, Cross Island, decline, Kaktovik, polar bear, population size, sea ice, Southern Beaufort, terrestrial foods, whale carcasses
The other day, I got a call from an international journalist who admitted he’d done no research into the polar bear issue but believed, based on media reports he’d heard, that there must only be about 100-200 bears remaining in the Arctic. I know he’s not alone.
This journalist was utterly astonished to learn that the IUCN Red List assessment in 2015 put the polar bear population total at 22,000-31,000 bears and demanded proof that this was true.
Here is a summary of the Red List report, with references and links to the report:
The 2015 IUCN Red List assessment update for polar bears (published 18 November 2015) states that the global polar bear population is 22,000 – 31,000 (26,000), that the current trend is ‘unknown’ and that there is only a 70% chance that polar bear numbers will decline by 30% in 35 years (with virtually zero chance that the numbers will decline by 80% or more by 2050) – in other words, zero chance of extinction. [Detailed in a document called 22823 Ursus maritimus]. It classifies the polar bear as ‘vulnerable’ to extinction based on predictions of future sea ice decline due to global warming [similar to ‘threatened’ by other organizations] Pdf here.
Below is a list of what truly worrying species declines look like: that is, animals whose numbers have actually declined, no prophesies involved (Adler 2008).
Posted in Advocacy, Conservation Status, Population, Sea ice habitat
Tagged Amur tiger, climate change, decline, elephant seal, endangered, extinction, facts, fur seal, global warming, gray whale, hooded seal, IUCN, polar bear, predictions, projections, prophesy, rare species, Red list, sea ice, sea otter, Siberian tiger, status, Steller sea lion, threatened, vulnerable
You have to know that the 2015 IUCN Red List assessment for polar bears contains good news because no one is talking about it – and none of the online information sources I’ve checked have updated their polar bear profiles to reflect it.
For all its flaws (including the deceptive focus on summer sea ice), this Red List update is the most statistically robust, in-depth study of the conservation status of polar bears – why is it being ignored, especially by the conservation organizations people turn to for information online?
UPDATE: see 18 January 2016 post here.
Posted in Advocacy, Conservation Status
Tagged decline, Defenders of Wildlife, EOL, extinction, facts, information, IUCN, polar bear, Polar Bear Specialist Group, Polar Bears International, population size, Red list, sea ice, status, threatened, trend, Ursus maritimus, vulnerable, Wikipedia, WWF
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.
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).
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.
Posted in Advocacy, Conservation Status, Population
Tagged climage change, decline, generation time, global warming, IUCN, PGSG, polar bear, polar bear facts, population, Red list, sea ice, status, trend, vulnerable, Wiig
In The Arctic Journal, 7 October 2015: Unstable thinking about polar bear habitat [not my title choice]
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:
Posted in Conservation Status, Sea ice habitat
Tagged Arctic Journal, decline, GWPF, habitat, IUCN, polar bear, population size, sea ice, spring, summer, thick spring ice