Tag Archives: facts

Abrupt summer sea ice decline has not affected polar bear numbers as predicted

Yes, Arctic sea ice has declined since satellite records began in 1979 but polar bears have adjusted well to this change, especially to the abrupt decline to low summer sea ice levels that have been the norm since 2007.

Global pb population size sea ice 2017 July PolarBearScience

Some polar bear subpopulations have indeed spent more time on land in summer than in previous decades but this had little negative impact on health or survival and while polar bear attacks on humans appear to have increased in recent years (Wilder et al. 2017), the reasons for this are not clear: reduced summer sea ice is almost certainly not the causal factor (see previous post here).

Ultimately, there is little reason to accept as plausible the computer models (e.g. Atwood et al. 2016; Regehr et al. 2016) that suggest polar bear numbers will decline by 30% or more within a few decades: even the IUCN Red List assessment (Wiig et al. 2015) determined the probability of that happening was only 70%.

Arctic sea ice has never been a stable living platform (Crockford 2015): it shifts from season to season, year to year, and millennia to millennia. Without the ability to adapt to changing conditions, Arctic species like polar bears and their prey species (seals, walrus, beluga, narwhal) would not have survived the unimaginably extreme changes in ice extent and thickness that have occurred over the last 30,000 years, let alone the extremes of sea ice they endured in the last 200,000 years or so.

Some biologists continue to hawk doomsday scenarios for polar bears due to summer sea ice loss but the truth is that their previous predictions based on sea ice declines failed so miserably (e.g. Amstrup et al. 2007) that it’s impossible to take the new ones seriously — especially since the basic assumptions that caused the first predictions to fail have not been corrected, as I’ve stated in print (Crockford 2017:27):

In summary, recent research has shown that most bears are capable of surviving a summer fast of five months or so as long as they have fed sufficiently from late winter through spring, which appears to have taken place since 2007 despite marked declines in summer sea ice extent.

The assumption that summer sea ice is critical feeding habitat for polar bears is not supported.

Recent research shows that changes in summer ice extent generally matter much less than assumed in predictive polar bear survival models of the early 2000s as well as in recent models devised to replace them (Amstrup et al. 2010; Atwood et al. 2016a; Regehr et al. 2015; Regeher et al. 2016; Wiig et al. 2015), while variations in spring ice conditions matter more.

As a consequence, the evidence to date suggests that even if an ‘ice-free’ summer occurs sometime in the future ­ defined as sea ice extent of 1 million km2 or less (Jahn et al. 2016) ­ it is unlikely to have a devastating impact on polar bears or their prey. [my bold]

The abrupt drop in summer sea ice that occurred in 2007 was not predicted by experts to occur until mid-century yet the predicted decimation of polar bears worldwide expected under those conditions (a loss of 2/3 of the global total, to only about 6660-8325 bears) not only did not happen, it did not come even close to happening (Crockford 2017; see also my recent books, Polar Bear Facts & Myths, and Polar Bears: Outstanding Survivors of Climate Change, sidebar).

Instead, the global population grew from about 22,550 bears in 2005 to about 28,500 bears in 2015. And while this might not be a statistically significant increase (due to the very wide margins of error for polar bear estimates), it is absolutely not a decline.

The present reality is that low summer sea ice cover since 2007 has not caused polar bear numbers to decline and therefore, polar bears are not a species in trouble. This suggests that even if the Arctic should become briefly ice-free in summer in the future, polar bears are likely to be only minimally affected and not become threatened with extinction. Polar bears are outstanding survivors of climate change: recent research and their evolutionary history confirm this to be true.

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Exposing the failed polar bear scare to a an enthusiastic and influential audience

I’ve just returned from a few days in Washington DC, where I presented the details on the global warming icon that refused to die as modeled (see my slide #12 below) to an enthusiastic and influential audience at The Heartland Institute‘s 12th International Climate Change Conference (ICCC-12).

Crockford 2017_Slide 12 screencap

Polar bear science got some long overdue scrutiny by a large number of people at this meeting. Not unexpectedly, a good many folks were surprised and outraged to learn how the polar bear/sea ice situation has actually unfolded compared to the predicted outcome and on-going media hype.

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Report of Hudson Bay polar bear onshore in winter is rare indeed – here’s why

Late February is still the dead of winter in the Arctic, a time when most polar bears are at their leanest and out on the sea ice trying to find seals – and that means yesterday’s report of a “very fat” polar bear onshore outside Inukjuak is unusual at face value – but my followup inquiry revealed details that make it even more startling.

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CBC North facebook entry 27 Feb 2017

At my request, CBC North reporter Priscilla Hwang reached out to the hunter involved, who is the mayor of the community. She was told the incident took place on Saturday 25 February 2017 and the very fat bear in the story was actually a young, subadult female.

Subadults are more likely to be in poorer condition than adults at any time of year, due to their lack of hunting experience and competition with adult males. So to see a young bear that’s very fat before the feeding begins is quite astonishing: it suggests that feeding opportunities out on Hudson Bay have been very good over the winter and/or this bear was a savvy hunter despite her youth.

According to the mayor’s report, this community hasn’t had a bear onshore in nearly 30 years. Polar bears in Hudson Bay travel with the retreating ice to the western and southern shores, so with some exceptions, bears usually only have access to the east coast during winter through spring.

Last winter saw an extraordinary number of reports of bears on shore in winter, most of them causing trouble (see summary here). This Inukjuak sighting is the second I’ve come across this year – the other was in Svalbard (a female with cubs). Whether this new pattern is due to more bears or lack of hunting leading to bears having less fear of people – or a bit of both – it’s not yet possible to say.

So under the circumstances, the mayor of Inukjuak’s decision to kill this bear for the protection of the community seems quite reasonable (given the extensive resources required in Svalbard to drive their problem bears away rather than kill them).

Excerpts from the CBC story, and some maps and charts, are below.
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Thriving numbers – & two great books – are ample reason to rejoice on Polar Bear Day

Ten years of summer sea ice levels expected to kill 2/3 of the world’s polar bears by 2050 instead saw polar bear numbers grow. And this year, there are also two fabulous books about polar bears and their outstanding success story to celebrate on International Polar Bear Day (Monday 27 February 2017).

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One is suitable for kids (Polar Bear Facts & Myths) and another for adults and teens who want the details (Polar Bears: Outstanding Survivors of Climate Change) – see the right sidebar to buy on Amazon or my author website for details on all additional formats. A couple of excerpts from them are below.

So forget turning down your thermostat in a pointless gesture to “reduce your carbon emissions and help polar bears” — as Polar Bears International advocates for Polar Bear Day. Instead, treat yourself or a friend and order a book with a rational approach to species survival.

Speaking of species survival, think about the inconsistency in how some species are treated according to the US Endangered Species Act (ESA). Humpback whale numbers recovered after decades of protection; in 2016, after the state of Alaska filed a petition to delist, most populations were officially removed from the ESA list of ‘threatened’ species.

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Humpback whale and calf, NOAA image.

In contrast, by 2015, polar bear numbers had also recovered despite years of low sea ice loss not predicted until 2050, yet remain officially ‘threatened’ with extinction.

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Fat bear family at Kaktovik, Alaska (Southern Beaufort), April 2016. USGS photo.

US National Marine Fisheries Service defended the delisting of humpback whales against activists who insisted human-caused global warming threatened the species, but the US Fish and Wildlife Service defends flawed polar bear prophesies.

My books lay out the polar bear success story: in simple form for younger readers and in detail for others. See the excerpts below.

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Polar bears have not been driven to the brink of extinction by global warming. In fact, they are thriving (see my final conclusions on pg. 30 of Polar Bears: Outstanding Survivors of Climate Change, above and pg. 32 of Polar Bear Facts & Myths below.

crockford-pb-facts-and-myths-2017-pg-32

If you’d like to support my efforts to bring this to everyone’s attention, please consider buying a copy or two of my books. If you’ve already done so, keep in mind that your local library might be glad to have copies donated. They also make great gifts.

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Listen to the evidence: polar bears are thriving in current sea ice habitat

Oddly, activist organization Polar Bears International recently updated their website and now suggest there is still time to save polar bears and sea ice – even though the IUCN Red List documented more polar bears alive in 2015 than at any time in the last 50 years, despite the recent decline of summer sea ice – and even more bizarrely, call for a public uprising.

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Polar Bears International (with three polar bear scientists on staff and other as active advisors) suggest that people who love polar bears should march the streets on Earth Day with scientists to demand (as concerned and engaged citizens) that world leaders take them seriously.

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Wow. I’ve been a career scientist for more than 40 years and I have to say, this is the oddest phenomenon I’ve encountered being advanced in the name of science. To me, it shows how disconnected these people are from what science is meant to be and what scientists are meant to do. Not just the polar bear scientists but the others like them that are behind this proposed march.

I recommend this blog post by Willis Eschenbach – an excerpt below.

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Polar bears onshore in Svalbard update: bears again run out of Longyearbyen

Update to 18 Jan 2017 post: For at least 10 days, officials in Longyearbyen, Svalbard have been trying to keep a particularly persistent female polar bear and her two cubs away from the community. After being chased away last week, Sunday night (22 Jan) the trio appeared again at dog kennels at the edge of town but this time, but this time officials drove them even further south.

svalbard-female-2-cubs-23-jan-2017_icepeople-news

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Polar bears onshore in Svalbard in most dangerous season for bear attacks

Yesterday marked the first report I’ve found for polar bears onshore this winter, in a potentially dangerous repeat of a pattern that has become all-too common in recent years (especially last year) with bear populations booming virtually everywhere (but especially around Svalbard).

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This is the leanest time of year for polar bears – fat Arctic seal pups won’t be available for another 2-3 months and meals for polar bears are hard to come by – and that makes the bears especially dangerous.

So, despite the marked lack of sea ice around Svalbard this winter, a female polar bear with two cubs were reported near the community of Longyearbyen (still enduring 24 hours of darkness) – on the west coast of the archipelago (see map above), where sea ice has been virtually non-existent for years (see map below).

Svalbard ice 2017 Jan 17_NIS.png

It appears these bears traveled overland from ice off the east coast. There is no mention in any of the reports that the bears were thin or in poor body condition, or had so far caused any of the problems for which desperately hungry polar bears are famous. However, one dog-sledding guide had a frightening encounter in the dark in this on-going saga that began over the weekend (details and photos below). Continue reading