Tag Archives: summer

Fat healthy polar bear update: hundreds of not-starving bears attracted to dead whale

Are the hundreds of polar bears spending the summer on Wrangel Island in the Chukchi Sea starving and desperate for any scrap of food? Hardly! Photos taken by Russian tourists on a cruise ship (19 September 2017) show a huge number of already-fat, healthy bears converging on a dead bowhead whale washed up on a beach. Most of these bears would have been without food since at least early August, when the last sea ice disappeared around the island, and will return to the ice by November.

Wrangel Island bears on whale_29 Sept 2017 SUN

This is what The Sun reported (29 September), based on a Siberian Times story (my bold):

The extraordinary sight was witnessed by tourists on an Arctic cruise aboard the Finnish-built MV Akademik Shokalskiy.

A source at Wrangel Island Nature Reserve said: “There were at least 230 polar bears, including single males, single females, mothers with cubs and even two mothers with four cubs each.”

Experts called the sight of so many polar bears together “unique”.

The huge number could in fact amount to as much one per cent of the entire world’s population of the creatures.

Tourists initially thought the bears were a flock of sheep after viewing them from a distance, The Siberian Times reports.

But as the boat drew closer, the lucky holidaymakers realised what they were witnessing.

Fat cubs of the year are seen in the photo below, from the Siberian Times story:

Wrangel Island bears on whale_29 Sept 2017 Siberian TimesA self-proclaimed science-based news site (LiveScience, 29 September) that picked up the story of this unique event had the temerity to suggest the bears might have been “hungrier than usual” due to global warming.

It deliberately conflates predictions of future starving bears due to low sea ice levels with this observation of many obviously not-starving bears checking out an attractive food source (my bold):

“It’s unclear, however, whether climate change had made these particular bears hungrier than usual. The frequency of starving polar bears is expected to increase as the climate warms and sea ice declines — not just because of climate change directly, but because ice loss is taking away seals, their main food source, Steven Amstrup, chief scientist at Polar Bears International, a nonprofit research organization dedicated to studying polar bears, told Live Science in 2015.”

Except that there is no evidence that ice loss is “taking seals away” — certainly not in the Chukchi Sea. Chukchi Sea seals have been found to be doing better with less ice than they were when there was more ice in the 1980s.

More below, including the location of Wrangel Island and sea ice maps.

UPDATE 2 October 2017: Sea ice in the Chukchi Sea has been lower this summer than over the last few years but the polar bears spending the ice-free season on Wrangel Island are still in good to excellent condition:

r02_Chukchi_Sea_ts_4km at 2017 Oct 1

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Problem polar bears in Churchill at this date show 2017 less than 2016 and 2015

Comparing Churchill problem bear statistics over a few years provides some critical perspective: this year, the bears are causing much fewer problems.

This 2nd week in September is no exception, being the 9th week ashore in all cases: 2017 (4-10 September, where I think “total number of polar bear occurrence reports to date” should be 64, not 53, see week 7 report here), 2016 (5-11 September), 2015 (7-13 September), where there were about 1/2 the number of bears in “jail” this year compared to the last two years (i. e., 6 vs. 11 and 12) and slightly more than 1/2 the number of occurrence reports in 2017 than in 2016 and 2015 (64 vs. 107 and 99):

2017 week 9 Sept 4-11 may be typo

2016-sept-5-11_week-9.jpg

2015 Sept 7-13_at Sept 14

 

 

Problem bear reports confirm Churchill polar bears are in excellent condition

Now that all bears are ashore for the season, the folks at the Polar Bear Alert program in Churchill note in their report for week 7 (21-27 August, 2017) that the bears ashore are in excellent condition (confirming reports on the first bears ashore in July):

Churchill PB reports_week 7_ Aug 21-27_2017_Aug 28

Rather marked contrast to the pessimistic spin on conditions from the field a few months ago:

[yes, a few bears fail to make it through the winter, especially young bears; but that has always been the case — it’s not a sign of human-caused global warming catastrophe]

Last week’s problem bear report also confirmed news from the Churchill Polar Bears website a few weeks ago that showed several images of very fat bears:

Churchill_PolarBears_FAT bear post_21 Aug 2017

See below for last year’s report for week 7 and this year’s report for week 8 (28 August-3 September). Western Hudson Bay polar bears that come ashore near Churchill, Manitoba are starting their third month on land this week, out of the five months or so they have spent ashore in recent years (about 3 weeks more than in the 1980s, no longer than they did in 2004 — conditions have not been getting worse).

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New paper updates lack of trend in W Hudson Bay breakup/freeze-up dates to 2015

A newly-published paper shows that there has been no trend in the time Western Hudson Bay polar bears spent onshore between 2001-2015 due to sea ice conditions at breakup or freeze-up (previously available to 2010 only), despite the marked decline of global sea ice since 2007.

castro-de-la-guardia-et-al-derocher-2017-fig-3-no-caption

Figure 3 from Castro de la Guardia and colleagues (2017) showing freeze-up and breakup dates and ice-free days 1979-2015 for Western Hudson Bay. Figure with caption, copied below, explains symbols.

Previously, a 2007 paper by Eric Regehr and colleagues for WHB bears up to 2004, which was used to support the US bid to list polar bears as ‘threatened’ with extinction, concluded that between 1984 and 2003, bears were spending 3 weeks longer onshore than they did in the 1980s.

The big news from Castro de la Guardia et al. (2017) is that polar bears spent longer onshore from 1979-2015 by … 3 weeks. That is, no change from the situation in 2004. Wow!

Note the population size of the entire WHB subpopulation has also not declined since 2004 and is currently estimated at about 1030, based on a 2011 aerial survey (Stapleton et al. 2014).

Thanks to Andrew Derocher for the heads-up tweet.

From the abstract (my bold):

We found that the ice-free period in this region lengthened by 3 ± 0.8 wk over the period 1979−2015. Polar bears migrated onshore 2 wk earlier and offshore 1 wk later in the period 2005−2015 than in 1980−1989.

Here is the region in question, illustrated by Fig. 1 from the paper:

castro-de-la-guardia-et-al-derocher-2017-fig-1a-locationThe significant information contained in this paper is breakup and freeze-up dates and length of the ice-free period data for 2010-2015, which has been unavailable until now. More excerpts and comments below, including Figure 3 with its caption. Continue reading

Arctic sea ice grows & Churchill polar bears into their 4th month of fasting

A quiet year for problems in the polar bear capital of the world (Churchill, Manitoba) so far – despite this year tying for the second-lowest minimum since 1979 – and the ice is growing fast. In fact, Arctic ice growth in the second half of September was rapid and there is now more ice than there was at this date in 2007 and 2012 (when polar bears in those regions considered most at risk did not die off in droves).

masie_all_zoom_4km-2016-oct-12

Pessimistic polar bear specialists are wrong  – polar bears are much more resilient to low sea ice levels in summer than they assume: their own data from low summer ice years proves it.  If you’ll recall from my previous post, polar bears seem to have barely survived the extensive sea ice coverage during the Last Glacial Maximum – in other words, too much ice (even over the short term) is their biggest threat. Polar bear numbers, as confirmed by the latest estimates in the 2015 IUCN Red List assessment, are higher now than they have been since the 1960s, despite almost 10 years of summer sea ice minimums below 5.0 mk2.

Churchill Polar Bear Alert reports and Arctic sea ice comparisons at this date, in detail below.

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Polar bear onshore in Tuktoyaktuk got so close to kids they heard it breathing

A report from the CBC this morning (with video) of a large polar bear wandering about the village of Tuktoyaktuk on the (Canadian) shore of the Eastern Beaufort Sea on Thursday (29 September) that got very close to a group of children playing outside. Fortunately, no one was hurt.

tuk-polar-bear-sighting-sept-29_cbc-oct-1-2016-headline

That this was a rare event is evident in the awe and excitement in the voices of the residents as someone recorded the movements of the bear through town (picture quality is not the best, but clear enough).

As I’ve said before, with more bears we can expect more interactions with people and more sightings like this that haven’t happened in decades. Map and quotes below.
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Polar bears seldom catch seals they stalk in summer – it’s why they fast

This short BBC video shows why polar bears are so often unsuccessful in their summer hunts – adult bearded seals are the species most often available on the ice. These seals are not only predator-savvy but there are lots of escape routes in the melting ice, and this has always been so.

“Hungry polar bear surprises a seal – The Hunt: Episode 2 Preview – BBC One”

Melting ice in summer is not a new phenomenon (e.g. NASA photo below from mid-July 2016) – Thomas Grenfell and Gary Maykut described the process of melt pond development back in the 1970s:

“Melt ponds reach the maximum extent shortly after the disappearance of the snow, when they may cover upwards of 50% of the ice.”

sea-ice_melt-ponds_nasa-taken-13july2016_sm

Melting summer ice has always made it challenging for polar bears to catch seals, as this quote from Ian Stirling (1974) show, based on his work in the Central Canadian Arctic in the summer of 1973 (July and August):

There is a great abundance of natural holes in the ice during summer, anyone of which a seal could surface through.

This is still true in areas like the Southern Beaufort Sea today (e.g. Whiteman et al. 2015): the ice melts and in some areas, disappears completely in summer.

It’s why polar bears – unlike other species of bears in summer – depend on their stored fat to see them through until the ice reforms in the fall.

The meme “If there’s no ice, there’s no ice bear” is political-style rhetoric, not science.

[When polar bear scientists say “sea ice” or “ice” – they mean summer sea ice. Sea ice in winter and spring are not predicted to decline by 2100 to any appreciable degree and that has been true since sea ice predictions began]

Polar bears in Hudson Bay and Davis Strait routinely go 4-5 months without sea ice in the summer and have done since studies on them began. Yet, all of the polar bear subpopulations in Hudson Bay and Davis Strait are stable or increasing.

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