Tag Archives: summer

Sea ice adjacent to all major polar bear onshore summer refugia at 31 July 2019

For all the hand-wringing over sea ice extent this year and its supposed similarity to 2012, what is truly remarkable is that at the end of July ice remains adjacent to every single major terrestrial summer refugia known to be important for polar bears. Those refugia sites include (from west to east, starting in the Chukchi Sea): Wrangel Island, western Chukotka, Severnaya Zemlya, Franz Josef Land, East Greenland, virtually all the islands of the Canadian Arctic Archipelago (including Southampton Island in Foxe Basin and the southwest and eastern coasts of Baffin Island), and Western Hudson Bay.

masie_all_zoom_4km 2019 July 31

Few bears spend the entire summer onshore along the Alaska coast: most still spend the summer on the sea ice and move with it as it contracts toward the Arctic Basin, as do many bears in the Barents, Kara, East Siberian, and Chukchi Seas. Until a few weeks ago, however, there was enough ice present that Beaufort Sea bears could go ashore if they wanted to do so. Continue reading

10 fallacies about Arctic sea ice & polar bear survival: teachers & parents take note

Summer sea ice loss is finally ramping up: first year is disappearing, as it has done every year since ice came to the Arctic millions of years ago. But critical misconceptions, fallacies, and disinformation abound regarding Arctic sea ice and polar bear survival. Ahead of Arctic Sea Ice Day (15 July), here are 10 fallacies that teachers and parents especially need to know about.

Polar_Bear_Summer_2 FINAL (2)

The cartoon above was done by Josh: you can drop off the price of a beer (or more) for his efforts here.

As always, please contact me if you would like to examine any of the references included in this post. These references are what make my efforts different from the activist organization Polar Bears International. PBI virtually never provide references within the content it provides, including material it presents as ‘educational’. Links to previous posts of mine that provide expanded explanations, images, and additional references are provided.

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Images from 2017 and 2018 show polar bears thriving in a warming world

Candid images of fat, healthy bears taken over the last two years by unbiased photographers across the Arctic are representative of the state of polar bears in a world that’s warmer than it was in 1980.

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Chukchi Sea polar bear on the sea ice, early August 2018. A Khan, NSIDC. Chukchi Sea bears are thriving, according to a new survey of the population.

It may seem counter-intuitive but it’s true: polar bears are thriving with less summer sea ice and there are more bears now than there were in 2005 (not a statistically significant amount more, but more nevertheless).

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Now at least 10 years with sea ice at 2050-like levels yet polar bears are still abundant

We’ve hit the seasonal Arctic sea ice minimum for this year, called this morning by US NSIDC for 19th and 23rd of Septmeber: 4.59 mkm2, the same extent as 2008 and 2010. This is not a “ho-hum” year for polar bears: it means that since 2007, they have triumphed through 10 or 11 years1 with summer ice coverage below 5.0 mkm2 —  levels that in 2007 were expected to cause catastrophic declines in numbers.

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Summer sea ice below 5.0 mkm2 were not expected to occur until about 2050, according to 2005/2006 sea ice models and polar bear specialists at the US Geological Survey (USGS). Polar bear survival models predicted 2/3 of the world’s polar bears would disappear when ice levels reached this threshold for 8 out of 10 years (Amstrup et al. 2007, 2008; Hunter 2007) but polar bears have been more resilient than expected (Crockford 2017, 2018; Crockford and Geist 2018). In fact, in many areas (like the Chukchi Sea, Barents Sea and Foxe Basin) polar bears are thriving despite dramatic declines in summer sea ice coverage (Aars et al. 2017; ACSWG 2018; Peacock et al. 2013; Regehr et al. 2016; Stapleton et al. 2016).

The sea ice models used to support the addition of polar bears to the US Endangered Species List as ‘threatened’ with extinction suggested sea ice levels from 3-5 mkm2 would not occur unti mid-century, yet they dropped before the ink was dry on the 2007 USGS Reports (ACIA 2005; Hassol 2004; Holland et al. 2006; Solomon et al. 2007; Zhang and Walsh 2006).

The ice extent charts from the University of Bremen (below) show ice that’s 50% concentration or greater at the date of the seasonal minimum (19th September): what polar bear specialists define as preferred habitat (Amstrup et al. 2007).

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Compare the minimum shown above to the coverage predicted for 2050 and to coverage at the minimum in 2012 (the NSIDC image is here):

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Brace yourself: more starving polar bear news stories in the pipeline from Svalbard

A few polar bears have become stranded on small islands north of Svalbard since the local sea ice retreated — of which the bear that mauled a cruise ship guard last month was but one — and if return of the ice is as late as last year, those handful of bears are likely doomed to die of starvation. This is not due to climate change but rather bad judgment on the part of these few bears. They were not forced ashore: if they’d stayed on the ice like the rest of the population, they’d have likely been just fine.

Daily Mail stranded bear headline_3 Aug 2018 all

Similar to the bear in northwestern Hudson Bay that fatally mauled a young father in early July, these bears were likely lured ashore by the prospect of masses of bird eggs present on island rookeries. But they overstayed their window of opportunity and the ice retreated without them.

Fledgling birds and bird eggs are not replacements for seals in a bear’s diet but when the season of easy seal kills winds down, as it does in late spring, easy-picking sea bird eggs may be enticing enough to lure a few bears ashore when they’d be better off on the ice.

That is not the fault of climate change.

Unlike bears in Hudson Bay and many other regions — including the Lancaster Sound area of Canada where the National Geographic “starving” bear was filmed last summer — these bears were not forced ashore by retreating ice: they chose to do so.
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Sea ice is critical habitat for polar bears from late fall through late spring only

Sea ice is said to be “an essential habitat for polar bears” but that’s an overly simplistic advocacy meme as ridiculous as the “no sea ice, no polar bears” message with which the public is constantly bombarded. Polar bears require sea ice from late fall to late spring only: from early summer to mid-fall, sea ice is optional. Historical evidence of polar bears that spent 5 months on land during the summer of 1874 proves an extended stay ashore is a natural response of polar bears to natural summer ice retreat, not a consequence of recent human-caused global warming. Sea ice is a seasonal requirement for polar bears: it’s not necessary year round.

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[This PBI newsletter from 2011 repeats this meme and Andrew Derocher’s recent tweet conveys a similar message (“Sea ice loss = habitat loss for polar bears”)]

As long as sea ice is available from late fall through late spring (December to early June) and accompanied by abundant seal prey (sometimes it isn’t, see Derocher and Stirling 1995; Stirling 2002; Stirling et al. 1981, 1982, 1984), polar bears can survive a complete or nearly complete fast from June to late November (and pregnant females from June to early April the following year). That’s the beauty of their Arctic adaptation: fat deposited in early spring allows polar bears to survive an extraordinary fast whether they spend the time on land or sea ice.

Young and very old bears, as well as sick and injured ones, are the exception: these bears often come ashore in poor condition and end up dying of starvation — as a much-publicized bear on Baffin Island who likely had a form of cancer did last summer (Crockford 2018). Competition with bigger, stronger bears means these bears can’t keep what they are able to kill and they are most often the bears who cause problems. Starvation is the leading natural cause of death for polar bears because if they cannot put on the fat they need in spring, they will not survive the low food months of summer and winter, whether they are on land or out on the sea ice (Amstrup 2003). Continue reading

Just look at what the ‘global heat wave’ is doing to polar bear sea ice habitat!

According to the Guardian (9 July 2018), there is a “global heat wave” going on right now.

In Siberia, the heat is supposedly “completely unprecedented” and will surely (we are told) impact Arctic sea ice — the habitat of the iconic polar bear.  Yet a comparison of previous years shows little to no impact on sea ice: there is more ice present than there was in 2007.

Polar Bear Breaks Ice

Said The Guardian:

“But though we cannot say definitively that the current heatwave is caused by carbon emissions, it fits the pattern of long-term changes that we call climate. It is part of a global phenomenon, even if not the most important part. The really significant change is happening in eastern Siberia at the moment, where a completely unprecedented heatwave is warming that Arctic coastline, with consequences that are unpredictable in detail but surely bad on a large scale.” [my bold]

The heat — which some folks admit they not only expect during this season called summer but anticipate with joy — has been around since late June, with several locales outside Siberia affected, including southern Ontario, Quebec, Los Angeles CA, Britan, many locations in the eastern USA, Europe.

With so many locations across the Northern Hemisphere experiencing very hot weather over the last few weeks (maybe record-breaking, maybe not), let’s take a look at what all that heat is doing to Arctic sea ice compared to previous years.
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