Here are the six most important polar bear stories I wrote about in 2020 that are worth reading if you missed them.
These posts cover new evidence that polar bears are thriving (including more populations stable or increasing) despite recent declines in summer sea ice blamed on climate change, an explanation of why the simplistic ‘less ice, fewer bears’ is false and a short post that shows a much-publicized new model predicting future extinction of polar bears is scientifically implausible. Honourable mention goes to a story refuting the claim that Alaskan polar bear cubs are at risk from oil exploration in coastal Wildlife Refuge.
Posted in Advocacy, Conservation Status, Population, Sea ice habitat, Summary
Tagged Alaska Wildlife Refuge, climate change, facts, polar bear, population size, sea ice, sea ice loss
Final reports for two Canadian subpopulations reveal the number of polar bears in M’Clintock Channel has more than doubled since 2000 while Gulf of Boothia as remained about the same despite moderate declines in summer sea ice cover. All of the survey results were published online yesterday (16 November 2020) and I was alerted to the posting this morning via email by a Nunavut employee.
What may seem like a silly question is actually fundamental to polar bear survival: in the fall, why do Western Hudson Bay bears correctly expect to find seals in the new ice that forms offshore? Why are seals attracted to that new ice – called ‘shorefast ice’ or ‘fast ice’ – when they would clearly be safer out in the open water where there is no ice and no bears?
As the picture below attests, polar bears can and do kill ringed seals in the new ice that forms off the coast of Western Hudson Bay even when it is but a narrow strip of thin ice – and so close to shore their successes can be caught on camera.
Three adult male polar bears share a seal kill on the newly-formed ice off Wapusk National Park, Western Hudson Bay. 5 November 2020. Buggy cam, Explore.org
A different bear was also filmed killing another seal on 31 October. And these are only the kills we know about along a very short stretch of coast – the killing is almost certainly going on up and down the entire coast, into James Bay (see below), where there is just as much ice but no cameras.
As far as I am aware, this seal killing by polar bears goes on in newly-formed shorefast ice everywhere across the Arctic in early fall, not just in Hudson Bay. Although the timing varies, virtually everywhere in the peripheral seas of the Arctic Ocean (Barents, Kara, Laptev, Chukchi, Beaufort, as well as Baffin Bay and Davis Strait), shorefast ice forms before the mobile ice pack expands to meet the ice developing from shore.
This shorefast ice formation in fall provides a predictable but short-lived source of prey for polar bears as they strive to regain some of the weight lost over the summer.
Posted in Conservation Status, Evolution, hunting, Life History, Population, Sea ice habitat, Summary
Tagged fall, fast ice, hunting, ice formation, polar bear, sea ice, seals, shorefast ice
This is shaping up to be one of the shortest ice-free seasons in at least 20 years for both Western and Southern Hudson Bay polar bears.
Hudson Bay sea ice at 2 November 2020. NSIDC Masie chart.
Last week, sea ice started forming along the shore of Hudson Bay, from the north end all the way south into James Bay. So far, the shorefast ice that’s forming is only a narrow strip along the coast but is thickening and becoming broader each day, which means that unless something changes dramatically, the bears should all be on the ice at the end of the week, an exodus from shore that hasn’t happened this early in WH since 1993 (the earliest since 1979).
The last WH tagged polar bear didn’t leave the ice this year until 21 August, which means if it’s on the ice by the end of this week it will have spent only 11 weeks onshore – less than 3 months. Even the first bears that came ashore in mid-July will have only spent about 16 weeks on land – at least a month less than they did a decade ago (Stirling and Derocher 2012). Four months spent ashore was the historical average for Western Hudson Bay bears in the 1970s and 1980s (Stirling et al. 1977, 1999). This year, most polar bears will have spent only about 13-14 weeks on land because they did not come ashore until early August.
UPDATE 8 November 2020: Report from Churchill area polar bear guide Kelsey Eliasson, via Facebook Saturday 7 November: “Most bears have left on the ice – including peanut – but still some stragglers” [‘Peanut’ is a well-known female who has two cubs this year]. See below for sea ice chart for 8 November shows broadening band of grey ice clearly thick enough to support the weight of adult bears (and the same thing is happening in Southern Hudson Bay):
Posted in Conservation Status, Life History, Population, Sea ice habitat
Tagged breakup, Churchill, computer models, freeze-up, future, Hudson Bay, ice-free season, polar bear, predictions, sea ice
After spring polar bear research was cancelled in Western Hudson Bay (and pretty much everywhere else) this year because of Covid 19 concerns, it now transpires that fall research is out as well. Travel restrictions implemented by government departments and university administrations (not the health department) apparently mean fall programs to assess the health and status of polar bears in Western Hudson Bay have been put on hold.
Triplet litter of polar bear cubs spotted in Wakusp National Park, Western Hudson Bay. 23 October 2020. Courtesy Explore.org.
Posted in Advocacy, Population, science, Sea ice habitat
Tagged breakup, climate change, covid-19, field work, Hudson Bay, polar bear, restrictions, sea ice
A just-released report on the latest count for the Alaska portion of the Southern Beaufort subpopulation reveals that numbers have been stable since 2010 despite claims the population has continued to decline. However, the study also has a very odd feature: 2012 had the highest population estimate over the decade of 2006-2015 yet also had the lowest survival of all age classes since 2001.
Healthy polar bear male at Kaktovik, Alaska on the Southern Beaufort Sea, September 2019, Ed Boudreau photo, with permission.
However, what is essentially good news about polar bear health and survival in the Southern Beaufort has so far been glossed over by the media because the report prominently includes estimates of polar bear dens on land in areas of potential oil exploration, a highly politicized topic. Accordingly, the Washington Post (picked up by other outlets) focused a statement in the paper that “long-term persistence of polar bears (Ursus maritimus) is threatened by sea-ice loss due to climate change” and on the denning issue rather than the new population count. As far as I am aware, no other population estimate report has included such distracting information.
Recent claim of a polar bear expert [my bold]:
In 2015…the polar bear population in the Beaufort Sea had declined by 40% over the previous decade. “We can only anticipate that those declines have continued.” Steven Amstrup, 29 September 2019.
In an astonishing display of under-selling good news, the authors of a new paper announcing that Kane Basin polar bears are doing well have avoided mentioning that the population increased substantially since the 1990s and insist that any benefits will be short-lived.
Kane Basin population size at 2013 was 357 (range 221 – 493), up from 224 (range 145 – 303) in 1997. That’s an increase of 59% based on a 2016 recalculation of the 1997 population estimate of 164 (Crockford 2020) – it would have been a 118% increase otherwise.
Money quote: “We find that a small number of the world’s polar bears that live in multiyear ice regions are temporarily benefiting from climate change.” Kristen Laidre, lead author of Transient benefits of climate change for a high‐Arctic polar bear (Ursus maritimus) subpopulation
Both the paper and the press release also claim, despite acknowledging that there is no evidence for this conclusion (“the duration of these benefits is unknown“), that this good news will probably not last because computer models say beneficial conditions might not persist beyond the end of the century.
As always, if you’d like to see this paper, use the ‘contact me’ page to request a copy (it’s paywalled).
UPDATE 25 September 2020: News just out from Nunavut this morning, “New Nunavut polar bear surveys point to “currently healthy” populations in M’Clintock Channel and Boothia Bay.” The survey report for M’Clintock Channel (mentioned in the post below) and neighbouring Gulf of Bothia has still not been made public but this announcement suggests that population numbers in these subpopulations have also increased by some amount that will be similarly discounted as unimportant.
Posted in Conservation Status, Population, Sea ice habitat
Tagged annual ice, Kane Basin, Last Ice Area, M'Clintock Channel, models, more bears, multiyear ice, polar bear, productivity, sea ice
The annual summer sea ice minimum in the Arctic has been reached and while the precise extent has not yet been officially determined, it’s clear this will be the ‘second lowest’ minimum (after 2012) since 1979. However, as there is no evidence that polar bears were harmed by the 2012 ‘lowest’ summer sea ice this year’s ‘second-lowest’ is unlikely to have any negative effect.
This is not surprising since even 2nd lowest leaves summer ice coverage in the Arctic at the level sea ice experts wrongly predicted in 2005 wouldn’t be seen until 2050 (ACIA 2005; Amstrup et al. 2007; Wang and Overland 2012) and this is the same amount of summer sea ice that polar bear experts incorrectly predicted would cause 2/3 of all polar bears to disappear. My book explains how it all went wrong: The Polar Bear Catastrophe That Never Happened.
In this summary of how polar bears have been doing since the the lowest sea ice minimum in 2012, I show that contrary to all predictions, polar bears have been thriving despite reduced summer ice in the Barents, Chukchi and Southern Beaufort Seas, and because of unexpectedly short ice-free seasons in Hudson Bay and less multiyear ice in the Canadian Arctic Archipelago.
UPDATE 21 September (10:20 PT): NSIDC has just announced the Arctic sea ice extent minimum (preliminary) for 2020 at 3.74 mkm2 reached on 15 September. See full report here.
Posted in Conservation Status, Population, Sea ice habitat, Summary
Tagged Arctic, body condition, breakup, catastrophe, CO2, decline, extinction, freeze-up, minimum, multiyear ice, polar bear, sea ice, second-lowest, September, summer
An excellent summary of recent points I’ve made in my latest book and on this blog about the recent push to keep polar bear extinction panic alive with a new model of impending doom was published two days ago in the Spectator UK by columnist Ross Clark (23 July 2020, in Coffee House).
“Wouldn’t it be nice if we could debate climate change for five minutes without hearing about polar bears or being subjected to footage of them perched precariously on a melting ice floe? But that is a little too much to expect. Polar bears have become the pin-ups of climate change, the poor creatures who are supposed to jolt us out of thinking about abstract concepts and make us weep that our own selfishness is condemning these magnificent animals to a painful and hungry end.”
Read the whole thing here.
PS. I noticed Clark refers to me as an anthropologist. I have requested a correction because I am a zoologist.
Posted in academic freedom, Advocacy, Book promotion, Conservation Status, Population, Summary
Tagged climate change, contradictions, extinction, model, Nature Climate Change, polar bear
Here I take a detailed look at sea ice and polar bear population health information available for Western Hudson Bay and the Southern Beaufort compared to the Barents and Chukchi Seas. Data from the first two regions – but especially Western Hudson Bay – are used repeatedly to proclaim that a pronounced decline in summer sea ice since 1979 has caused harm to the health of global polar bear populations even though data from the second two regions strongly contradict such a conclusion, as I’ve pointed out in my fully referenced book, The Polar Bear Catastrophe That Never Happened.
These contradictions mean that studies from Western Hudson Bay and the Southern Beaufort should not be used to extrapolate to the rest of the Arctic with regard to how polar bears are responding to reduced summer sea ice. The plea to ‘Save Our Sea Ice‘ for the sake of polar bear survival is a climate change marketing slogan, not a scientific assessment.
Posted in Advocacy, Conservation Status, Population, Sea ice habitat, Summary
Tagged advocacy, Arctic sea ice day, contradictions, loss of summer ice, marketing, polar bear, Polar Bears International, predictions, save our sea ice, sea ice