Tag Archives: Arctic

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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Late winter polar bear habitat 2017 vs. 2006 and 2011 shows no trend

Here is a bit of historical perspective for rational readers trying to make sense of the doom-mongering of others that current sea ice conditions spell trouble for polar bears, given that the winter maximum extent for 2017 reached a new seasonal low (keeping in mind that NSIDC does not publish error bars for these measurements, which helps elevate such pronouncements to “news”).

Ice extent (courtesy NSIDC’s MASIE) at 25 March (Day 84) is below for 2017, 2011 and 2006, almost 3 weeks after the winter maximum was declared at 7 March for 2017, 9 March for  2011, and 12 March for 2006. Extent at the maximum for 2006 was estimated at 14.68 mkm2, 14.42 mkm2 for 2017, and 14.67 mkm2 in 2011 (what tiny differences make headlines these days).

Remember: there are no polar bears in the Sea of Okhotsk or in the Baltic Sea (marked with an * below) yet ice in those regions is included in the Arctic totals used to determine maximum seasonal extent. Much (and sometimes, all) of the “Arctic” variation in extent at this time of year is accounted for by variation in Sea of Okhotsk and Baltic Sea coverage.

Sea ice day 84 March 25 2017_2011_2006 labeled

Bottom line: total winter ice extent for the Arctic ≠ winter polar bear habitat and neither have changed much in a decade.

See close up of the above graphic below.

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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

No correlation between freeze-up dates for Hudson Bay & total Arctic ice cover

Guess which year between 2006 and 2016 had the latest start to freeze-up on Hudson Bay, given that 2012 had the lowest September average and 2007 and 2016 tied for second-lowest (see graph below, from NSIDC), and that sea ice in the Arctic right now is the lowest it’s been for this date since 1979?

sea-ice-sept-averages-graph-only-marked-for-2006-up

If you guessed anything other than 2010, you guessed wrong – in addition, 2006 (not 2016) was second latest.

There is no correlation between Arctic sea ice coverage and freeze-up dates for Western Hudson Bay.

Yet, Polar Bears International (“Save Our Sea Ice”) –  who were surely in and around Churchill in 2010 and 2006 watching polar bears – just posted an alarming statement about local conditions, implying that slow freeze-up of Hudson Bay this year is a reflection of the fact that “sea ice is at a record low across the Arctic.”

They also claim that “…the weather is the warmest we’ve ever seen at this time of year.” That may be true, but if so, it is also meaningless with respect to the progress of freeze-up.

Does no one at PBI remember the very late freeze-up of 2010 or 2006? Odd, that.

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Will Trump reverse ESA decisions listing polar bears & Arctic seals as threatened?

The New York Times reported this morning: “Donald Trump Is Elected President in Stunning Repudiation of the Establishment.”

I’ve never been very interested in politics but this result has me wondering. Could the new president reverse the Endangered Species Act (ESA) decisions listing polar bears and other species as ‘threatened’ with extinction due to future threats from global warming?

future-of-arctic-species-status-under-trump-presidency-9-nov-2016
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Fall Arctic ice growth often differs regionally: 2016 compared to other years

Arctic sea ice is spreading out quickly from its central basin summer refuge – according to this NSIDC Masie ice chart, it has already grown more than 2 mkm2 beyond the annual minimum reached in early September. Ice is already pushing south into the eastern Beaufort and the archipelago of Franz Josef Land in the Barents Sea.

masie-sea-ice-2016-oct-20-cropped-and-marked_polarbearscience

Over the next couple of weeks, shorefast ice will start forming along the coasts of North America and Eurasia (see the first bits off Alaska in the 21 October CIS map below), which will eventually meet the expanding Arctic Basin pack to fill the Basin and Canadian Arctic Archipelago with ice – as it has done for eons.

sea-ice-extent-canada-2016-oct-21_cis

The evidence from the last decade or so suggests that by the end of October, most of the Arctic north of the 79th parallel (see map below) will be filled with ice – although the Chukchi Sea (north of the Bering Strait) may not fill until sometime in November:

79-th-parallel-north_wikipedia

Polar bears usually resume hunting as soon as sea ice conditions permit in the fall, since it’s their last chance to top up their fat reserves before the dark and cold of winter when hunting may become next to impossible.

I’ve copied ice charts from the Masie archives for some previous years at 31 October below.

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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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