Tag Archives: survival

W Hudson Bay polar bears won’t have an early breakup year, according to sea ice charts

There is still a huge swath of highly concentrated thick first year ice (>1.2m) over most of Hudson Bay this week (19 June 2017) and even in the NW quadrant (the closest proxy we have for Western Hudson Bay), the weekly graph shows levels are greater than 2016, when WHB bears came off the ice in good condition about mid-July. All of which indicates 2017 won’t be an early sea ice breakup year for WHB polar bears.

Hudson Bay weekly ice stage of development 2017 June 19

There is thick first year ice (>1.2m, dark green) in patches along the west coast in the north and south. Thick first year ice also extends into Hudson Strait and Baffin Bay, with some medium first year ice (0.7-1.2m thick, bright green) along the central and southern coasts of WHB.  Note the red triangles incorporated into the thick ice of Hudson Strait in the chart above: those are icebergs from Greenland and/or Baffin Island glaciers. A similar phenomenon has been noted this year off northern Newfoundland, where very thick glacier ice became mixed with thick first year pack ice and were compacted against the shore by storm winds to create patches of sea ice 5-8 m thick.

Compare the above to what the ice looked like last year at this time (2016 20 June, below). There is more open water in the east this year (where few WHB bears would likely venture anyway) but less open water around Churchill and Wapusk National Park to the south than there was in 2016:

Hudson Bay ice age weekly at 20 June 2016

We won’t know for several more weeks if most WHB bears will come ashore at about the same time as last year (early to mid-July) or whether they will be in as good condition as they were last year (because winter conditions may not have been similar).

But so far, sea ice conditions are not looking as dire as the weekly “departure from normal” chart (below, 19 June 2017) might suggest (all that “less than normal” red and pink, oh no!!):

Hudson Bay weekly departure from normal 2017 June 19 Continue reading

Fake news on polar bear survival predictions is political posturing

I call this fake news because it’s not news – media headlines around the world today (New York Times, Washington Post, DailyMail) are trumpeting the release of a final version of a draft report released with similar fanfare more than a year ago, announced today by the US Fish & Wildlife Service in the official US government publication, Federal Register.

biggest-threat-to-polar-bears-is-global-warming-nyt-headline_9-jan-2017

Without action on climate change, say goodbye to polar bears” is exactly the kind of sensationalized nonsense I address in my new detailed science book, Polar Bears: Outstanding Survivors of Climate Change (announced here, discussed here).
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If experts had been right about sea ice, there would be no polar bears in Churchill

The simple fact is that if polar bear experts had been right about the threat to polar bears from the loss of summer sea ice in the Arctic, there would be no polar bears in Churchill this fall. No bears for tourists to photograph, none for biologists to study, and certainly none for the BBC to film for an upcoming three-part TV special called “Arctic Live.

polar-bear-stock-image-gg66298544_sm

The low-ice future that biologists said would doom polar bears to extinction by 2050 has already happened in 8 out of the last 10 years. The sea ice future has been realized.

Polar bears have experienced those supposedly deadly low-ice summers for almost a decade but the global population did not drop by 2/3 as predicted and not a single one of the ten subpopulations predicted to be extirpated under those conditions has been wiped out.

How much more wrong can you be than that? Will the BBC mention this conundrum in their show? Will the polar bear experts they consult share this fact with viewers? We’ll all have to watch and see [show times and summaries of each program here, 1-3 November] but here are some background facts that might enhance your viewing experience.

UPDATE: Sea ice condition of Hudson Bay at 1 November 2016 below from the Canadian Ice Service (some slushy ice looks to be forming along the coast north of Churchill – this is how freeze-up starts). See the animation for the last 10 days here:

sea-ice-extent-canada-2016-nov-1_cis

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Recent studies show Sept ice of 3-5 mkm2 did not kill polar bears off as predicted

The annual Arctic sea ice minimum for 2016 is imminent and the hand-wringing about polar bear survival has already begun. While this year is shaping up to be another very low sea ice minimum in the Arctic – not as low as 2012 but lower than as low as 2007 (previously the 2nd lowest since 1979) – contrary to predictions, several recent studies show that such low sea ice coverage in summer has had no (or very limited) negative effects on polar bear health and survival. In fact, for polar bears in some areas low summer sea ice has been quite beneficial (although these are not the populations that polar bear specialists predicted would do better).

polar_thin_ice Jessica Robertson_USGS

Since low summer extents of recent magnitude (3.0 – 5.0 mkm2) are clearly not any sort of threat to polar bears, it seems improbable that even an ice-free (≤ 1.0 mkm2) summer (e.g. Wang and Overland 2015) would be devastating to the species [don’t forget Cronin and Cronin 2016: they’ve survived such conditions before] – as long as conditions in spring allow for the necessary concentrated feeding on young seals.

sea-ice-mins_2007_2012_2015_polarbearscienceAbove: Top, minimum at 2012 (16 Sept, 3.41 mkm2, lowest since 1979); Center, 2007 (18 Sept, 4.17 mkm2); Bottom, 2015 (9 Sept, 4.50 mkm2), from NSIDC. Below: sea ice at 10 Sept 2016, 4.137 mkm2 – minimum not yet called).

sea-ice-extent-2016-sept-10_nsidc

Recall that in 2006, the IUCN Polar Bear Specialist Group based their conservation status of ‘vulnerable’ (likely to become threatened within the next 45 years due to reduced habitat) on the predictions of sea ice specialists (see 2008 update here).

Sea ice experts in 2005 predicted such low summer sea ice extents as polar bears have endured since 2007 (3.0 – 5.0 mkm2) would not happen until 2040-2070, at which time PBSG biologists said that >30% of the world’s bears would be gone.

Evidence to the contrary comes from polar bear specialists working in the Chukchi, Beaufort, and Barents Seas – and in Southern Hudson Bay – since 2007. Overall, the latest IUCN Red Book assessment (2015) put the global population size at 22,000-31,000 (or about 26,500).

All of this means that those polar bear experts were wrong: polar bears are more resilient to low summer sea ice conditions than they assumed.

UPDATE 2 January 2017: I’ve added some quotes from the original USGS reports that explicitly state their dire predictions for 2050 that differ from the predictions made by the IUCN Polar Bear Specialist Group.
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Tracking polar bears in the Beaufort Sea in July & sea ice comparison with 2007/2012

Only four Alaskan polar bear females had USGS satellite collars left transmitting locations in the Beaufort Sea and all four of these bears were on the ice during July, 2016. The same was true in June and May.

Beaufort tracking USGS bear-movements-July 2016 sm

Original caption: “Movements of 4 satellite-tagged polar bears for the month of July, 2016. Polar bears were tagged in 2015 and 2016 on the spring-time sea ice of the southern Beaufort Sea. All 4 of these bears have satellite collar transmitters. Polar bear satellite telemetry data are shown with AMSR2 remotely-sensed ice coverage from 31 July, 2016.” Original here.

 

There looks like a lot of open water for this time of year but in terms of absolute extent there is somewhat less ice than there was in 2007 and only slightly less than 2012, according to NSIDC Masie charts. And of course, what we know is that polar bears of the Chukchi Sea and the Southern Beaufort not only survived the low ice summers of 2007 and 2012, they thrived: CS bears were in great condition and reproducing well, and BS bears were recovering from the devastating thick ice conditions of the 2004-2006. Have a look at the maps below. Continue reading

Polar bear survival: habitat 2013 vs. 2016 for 22 January

Using sea ice maps issued by the National Sea Ice Data Center (NSIDC), it’s interesting to compare these two years with respect to polar bear health and survival (keeping in mind that no polar bears live in what I like to call the armpits of the Arctic – the Sea of Okhotsk, the Baltic Sea or in the Gulf of St. Lawrence)1:

22 January 2016

Sea ice extent 2016 Jan 22 NSIDC

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Summer polar bear habitat then & now – little impact from 2007 record-breaking sea ice low

Sea ice looks low for this time of year but how does it compare to 2007, when summer ice habitat for polar bears hit a record-breaking low?  What can the impact of 2007 ice levels on polar bears tell us about what to expect this year?

Sea ice at 2015 Aug 8 vs pb status map_Aug 9 2015 sm

By this date in 2007 (8 August, Day 220, NSIDC Masie map below), there was almost 1 million km2 less ice than there is this year (map above). However, look which polar bear subpopulations not only survived, but thrived, through the 2007 low ice summer: Chukchi Sea, Southern Beaufort, Barents Sea, Davis Strait, Foxe Basin, Western Hudson Bay, and Southern Hudson Bay. That’s all of the subpopulations for which we have recent data.

There is more than a month left in the melt season, of course. However, while 2012 finished with a lower minimum ice extent due to a massive mid-August storm that broke up a lot of ice (Simmonds and Rudeva 2012), by the end of the first week of August (i.e, the 8th), there was more  ice in 2012 than in 2007 and a bit less than this year (2012, 6.3 mkm2; 2007, 5.6 mkm2; 2015, 6.5 mkm2).

This means if less summer ice for a longer period of time impacts polar bear health and survival, conditions in 2007 should have had a noticeable impact on polar bears around the world. They didn’t. That suggests even if this September sea ice minimum is as low as 2007, it won’t have any negative impact on polar bear health or survival. The most profoundly negative documented impacts have come from thick sea ice in spring or  suboptimal spring snow levels (Crockford 2015) and the evidence shows that variation in the extent of summer ice is simply irrelevant to polar bears.

Sea ice at 2007 Aug 8_polarbearscience
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