Tag Archives: population decline

Fat polar bears [and lots of them] drive public confidence in future of the species

What is causing the death of the polar bear as a climate change icon? Fat bears are part of it, but mostly it’s the fact that polar bear numbers haven’t declined as predicted.

Western Hudson Bay polar bears around Churchill, Manitoba appear mostly in good shape this summer despite the very late freeze-up last fall, including the very fat bear caught on camera below (see more great pictures here):

Churchill_PolarBears_FAT bear post_21 Aug 2017

Not only have we been seeing pictures of fat bears rather than starving bears in recent years but there are lots of them, in Western Hudson Bay and other seasonal sea ice regions where there should be none (if the models had been correct). No wonder polar bears are falling out of favour as an icon for catastrophic human-caused global warming.

[Here’s another picture of a fat bear, this one from Svalbard]

Excuses for why the public is no longer worried about the future of polar bears include a recent claim by climate scientist Michael Mann that “by making polar bears and penguins the poster child for climate change, we have wrongly conveyed that this is some exotic problem far off.

But none of these apologists acknowledge the simple truth: the models that  predicted catastrophe for polar bears due to diminished summer sea ice turned out to be wrong. The sea ice declined but polar bears flourished. Polar bears in seasonal sea ice ecoregions like Western Hudson Bay and Baffin Bay didn’t die off due to climate change as people were told would happen — why should they believe any of the other scare stories?

In and around Churchill, where tourists flock to see Western Hudson Bay polar bears up close and personal, one bear in good condition recently ran through town:

Overall, there have been fewer problems or conflicts this year in Churchill compared to last (after 6 weeks of onshore living), see below.

Polar bears are no longer a useful global warming icon because they are thriving despite diminished sea ice: Churchill area polar bears are a good example.

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USGS ‘treadmill’ paper repeats bogus claim that ice loss harmed polar bears

The newest polar bear science paper making the rounds courtesy the US Geological Survey, is a perfect example of a statistically-significant result with no biological significance. While the results are rather lame, the paper is dangerous because it repeats the disingenuous claim (see Crockford 2017) that Southern Beaufort Sea polar bear numbers declined in recent years due to summer sea ice loss.

polar_bear_rubble_ice_Mike Lockhart USGS_8 April 2011

The USGS authors (Durner et al. 2017) know this harm-from-summer-ice-loss assertion is not true for the Southern Beaufort subpopulation but the more papers they can get into print that say so, the more likely it will be believed — and the less likely readers will check older literature that documents the recent decline in polar bear numbers was due to a three year period (2004-2006) when thick ice conditions in spring made seal hunting a challenge, a repeat of a well-known phenomenon (e.g. Stirling et al. 1980; Stirling 2002) unique to this region that has been documented since the 1960s.

The Durner paper (USGS press releaseIncreased Sea Ice Drift Puts Polar Bears on Faster Moving Treadmill” published online 6 June ahead of print) spins the research results as potentially significant bad news but in so doing reveals how desperate they have become to make the public and their biology colleagues believe that Southern Beaufort polar bears, among others, are being negatively affected by summer sea ice loss (as per Stirling and Derocher 2012).

Durner, G.M., Douglas, D.C., Albeke, S.E., Whiteman, J.P., Amstrup, S.C., Richardson, E., Wilson, R.R. and Ben-David, M. 2017. Increased Arctic sea ice drift alters adult female polar bear movements and energetics. Global Change Biology. DOI: 10.1111/gcb.13746 http://onlinelibrary.wiley.com/doi/10.1111/gcb.13746/abstract [paywalled]

In fact, the Durner et al. paper does not document any harm to polar bears from the proposed ‘treadmill’ effect of more rapidly moving ice for the period 1999-2013 compared to 1987-1998, but instead uses models to suggest bears might have to eat one to three more seals per year to compensate for the extra energy needed to walk against the moving ice. That’s right: perhaps only 1 more seal per year out of the 50 or so they would usually consume (see Stirling and Øritsland 1995). In my opinion, that’s a pretty lame result for what one of the co-authors described as an immense amount of work.

News outlets have essentially used the USGS press release as a click-bait lede for another round of Trump-bashing with respect to the Paris climate change agreement, see here and here: the stories are hardly about polar bears at all. And predictably, polar bear activist and co-author Steven Amstrup (paid spokesperson for Polar Bears International, famous for their “Save Our Sea Ice” campaign) appears to be using the same approach: an up-coming call-in talk radio program at NPR’s Anchorage affiliate KSKA for Tuesday 13 June at 10:00 (Alaska time, see “Talk of Alaska”) is being billed as a discussion of “polar bears, climate change, and the Paris Accord” (h/t AK geologist). Continue reading

Polar bear habitat message for the year end: 2016 Arctic ice extent same as 2010

According to NSIDC daily sea ice interactive graph,  there was ever so slightly more ice on 31 Dec 2016 than on that date in 2010. However, the corresponding ice maps show just how differently that ice was distributed.

sea-ice-at-31-dec-2016_vs-2010_nsidc-interactive

Recall that in 2010, there was no huge die-off of polar bears attributed to reduced amounts of sea ice in the fall (or to reduced ice in summer, for that matter) because there was no catastrophic die-off at all.

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Hudson Bay could be ice-free in winter within 5-10 years, says seal researcher

Ringed seal biologist Steven Ferguson, in a statement to a reporter from the Winnipeg Free Press, made one of the boldest predictions I’ve ever heard:

crystalball_468x317_predictions_sq

 

“Hudson Bay could experience its first free winter within 5-10 years.”

You heard it here, folks. It appears Ferguson thinks Hudson Bay was never ice-free in winter even during the Eemian Interglacial, when the Bering Sea was ice-free in winter – something that has not come close happening in recent years (Polyak et al. 2010:1769).

Sounds like a bit of ill-advised grandstanding to me.

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Columnist admits video on polar bears and global warming contained a serious error

Since mid-August,  Vancouver Sun columnist Daphne Bramham has been filing a series of articles from an expedition cruise through the Northwest Passage for a feature called “Above the Arctic Circle”. One of these appeared on August 18, along with a video called “What to know about polar bears and global warming” and it contained an egregious error that should have stood out to any educated person as being wrong by several orders of magnitude:

What to know about pbs GW_Video_screencap 2_SUN_18 Aug 2016 marked

We are not talking about a difference of opinion or interpretation but a simple fact that was outrageously wrong by a wide margin. You see it, don’t you? Continue reading

Polar bears barely survived the sea ice habitat changes of the last Ice Age, evidence suggests

While the polar bear is an Ice Age species, genetic and fossil evidence suggests it barely survived the profound sea ice changes associated with the Last Glacial Maximum, one of the most severe glacial periods of the Pleistocene.

polar_bear_usfws_no date_sm

A map of sea ice extent at the climax of the Last Glacial Maximum (both perennial and seasonal ice), prepared with the help of a colleague, makes it possible to discuss what genetic and fossil evidence can tell us about the probable effects of glacial conditions on polar bears and ringed seals.

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Graphing polar bear population estimates over time

I’ve already commented on the 2013 update of polar bear population status released by the IUCN Polar Bear Specialist Group (PBSG).

However, I thought it might be interesting to graph the changes in global population estimates over time (from 1981-2013) — not just the actual estimates from PBSG status tables (with their min/max error ranges) but those totals plus the so-called “inaccurate” estimates that the PBSG have dropped from their accounts in recent (2005-2013) assessments: Chukchi Sea, East Greenland, Queen Elizabeth Islands (now known as the “Arctic Basin”), and Laptev Sea.

In 2001, those “inaccurate” estimates contributed 5,000-5,400 bears to the global total, but now they’re gone — no bears from those regions contribute to the official totals listed on recent PBSG status tables.

Adding those dropped estimates back into the global totals makes it possible to generate a graph in which the global estimates are truly comparable over time.

To see how the dropped estimates influenced the perception of population change over time, I’ve also graphed the estimates given by the PBSG in their status tables. I’ve combined the two into one image (Fig. 1, click to enlarge) to make comparison easy.

UPDATE 5 December 2014: Links to more recent posts relevant to this issue added below. The most recent numbers, added 31 May 2015, are here.
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