In 1983, it was claimed that freeze-up of Hudson Bay was so late that polar bears didn’t leave the shore until the 4th of December – several weeks later than had been usual at that time. However, the fact that sea ice charts show significant ice offshore weeks before that time suggests something else was probably going on.
About three weeks ago, CBC News republished an article (with video) from their 1983 archives for 1 December, about the plight of the people of Churchill who had already suffered one death and one serious mauling by polar bears. That was thirty-seven years ago, long before lack of sea ice was blamed for everything bad that happened to Western Hudson Bay polar bears. In fact, rather than a really late freeze-up, it appears the problem had more to do with the fact the bears had had an especially tough spring that year and arrived onshore in only ‘OK’ condition – and as a consequence, the town dump became such a strong attractant for many bears that they were reluctant to leave when the sea ice formed offshore.
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
The chart below shows what sea ice thickness over Hudson Bay was like at the first week of May in a so-called a ‘good year’ (2019) – when polar bears came off the ice in excellent condition late in the summer and left early in the fall (‘thick first year ice’ is dark green and indicates ice greater than 1.2m thick):
Hudson Bay ice conditions this year appear to be shaping up to be as good or better than last year for polar bears yet specialist researchers and their cheerleaders have still been claiming that bears in this region – Western and Southern Hudson Bay – are doomed because of poor ice conditions. It’s no wonder they still haven’t published the data they’ve been collecting on polar bear body condition and cub survival over the last 15 years or so (Crockford 2020). With most field work cancelled for this year, what’s their excuse for not getting that done?
A recent paper that attempted to correlate pollution levels and body condition in Barents Sea polar bears reports it found body condition of female bears had increased between 2004 and 2017 despite a pronounced decline in summer and winter sea ice extent.
“Unexpectedly, body condition of female polar bears from the Barents Sea has increased after 2005, although sea ice has retreated by ∼50% since the late 1990s in the area, and the length of the ice-free season has increased by over 20 weeks between 1979 and 2013. These changes are also accompanied by winter sea ice retreat that is especially pronounced in the Barents Sea compared to other Arctic areas” [Lippold et al. 2019:988]
Posted in academic freedom, Conservation Status, Life History, Population, Sea ice habitat
Tagged Barents Sea, body condition, denier, deplatformed, ice-free season, polar bear, sea ice, summer, Svalbard, threatened, vulnerable
An article by CBC News today (3 March 2020) is a surprisingly well-balance report on a recently published paper by Kristin Laidre and colleagues on their work on Baffin Bay polar bears that I discussed last month. It presents the Inuit perspective that polar bears are currently abundant in the area and the population stable despite less summer sea ice and some documented declines in body weight and at least one scientist conceded this is indeed true.
However, the CBC writer still left out the most critical caveat included in the paper about the study: that factors other than changes in sea ice could have affected the body condition and litter size data that the authors documented but they didn’t look at anything except sea ice. This automatically means the conclusions are scientifically inconclusive.
See some quotes below from the CBC article and the caveat from the paper. Continue reading
Posted in Conservation Status, Population, Sea ice habitat
Tagged abundant, baffin bay, body condition, causation, caveat, correlation, polar bear, population size, sea ice, stable
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.
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.
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.
Posted in Life History, Population, Sea ice habitat
Tagged Barents Sea, body condition, cub survival, denning, facts, Franz Josef Land, polar bear, science, sea ice, Svalbard
A new paper on Baffin Bay polar bears reports data on body condition and litter sizes collected as part of a major study of the region completed in 2013 compared to sea ice declines since the 1990s; based on a computer model, the authors predict that in 37 years time (if sea ice declines continuously), the incidence of twin litters could “largely disappear.” However, no decline in population numbers was predicted and a critical caveat acknowledges that factors other than changes in sea ice could have affected the body condition and litter size data the authors analyzed, which means the conclusions are scientifically inconclusive.
The last (2013) polar bear population survey of Baffin Bay (SWG 2016) generated an estimate of almost 3,000 (2,826; range 2,059-3,593), which means that regardless of some slight changes in body condition and litter size over the last two decades (which may or may not have been caused by loss of sea ice), there are currently a lot of bears in Baffin Bay.
Posted in Conservation Status, Life History, Sea ice habitat
Tagged baffin bay, body condition, causation, correlation, extinction, fatness, Greenland, litter size, NASA, polar bear, sea ice, weight
This is week 15 for most polar bears onshore near Churchill in Western Hudson Bay, which means they have been onshore for almost 4 months. Still, photos being circulated are still showing bears in excellent condition and we are just waiting to see if freeze-up this year is as early as it has been for the last two years.
Polar bear researcher Andrew Derocher says it takes four years of good sea ice conditions to recruit a polar bear from birth but implies that 2019 is the first year in decades that conditions for bears have been ‘good’ in Western Hudson Bay. He thinks he can get away with saying this because he hasn’t published any of the data on body weight and body condition he’s collected on these bears over the last 25 years (apparently, whatever funding agency pays for his research does not require him to publish the data he collects).
But independent observations such as dates of ice freeze-up in fall, ice breakup in summer, dates and condition of bears recorded onshore, suggest he’s blowing smoke: at least five out of five of the last sea ice seasons for WH bears have been good. That means we should be seeing more bears in the next official population count.
Posted in Advocacy, Conservation Status, Polar bear attacks, Sea ice habitat
Tagged body condition, breakup, Derocher, fat bears, freeze-up, Hudson Bay, polar bear, sea ice, thriving
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.
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).
Posted in Conservation Status, Polar bear attacks, Population
Tagged Arviat, attacks, body condition, cub survival, Derocher, estimates, fat, Hudson Bay, polar bear, population, problem bears, sea ice