Tag Archives: NSIDC

Hudson Bay breakup later than average, longer hunting season for polar bears

Due to the atypical pattern of sea ice melt on Hudson Bay this year, 2015 will definitely be a later than average breakup year – perhaps not as late as 1992 but maybe almost as late as 2009. Easing into the first days of Arctic summer, there is still a lot of polar bear habitat left on Hudson Bay, especially in the east.

Hudson Bay breakup 2015 vs 2009 at 29 June_MASIE

Although official breakup in 2009 was only a little later than usual (9 July), bears came ashore about the same time (after mid-August) as they did in 1992, when breakup was very late (30 July). With the pattern this year being so unusual (and the melt so slow over the last few weeks), who knows how late it could be before the last bears leave the ice in 2015?

There is definitely more sea ice this year on the bay than there was last year, when breakup was about average for the last 24 years.

UPDATE 2 July 2015: CIS weekly ice coverage graphs added to the end of this post. Hudson Bay ice highest since 2009 and Davis Strait highest since 1994! Have a look.
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Many polar bears cubs seen in Svalbard this year, says Norwegian biologist

Good news from Norway: polar bears around Svalbard are in excellent condition this spring and many females with new cubs have been spotted. This is a marked turn around from conditions just last year.

 Roy Mangersnes / Wildphoto

Roy Mangersnes / Wildphoto

According to a Norwegian news outlet yesterday, Jon Aars (Fig. 1, below), from the Norwegian Polar Institute, confirms that this has been an excellent year for polar bear cubs around Svalbard because there has been abundant sea ice near denning areas on the east coast.

Figure 1. Biologist Jon Aars with a Svalbard cub.

Figure 1. Biologist Jon Aars with a Svalbard cub.

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Polar bear habitat update – sea ice for hunting plentiful in all subpopulation regions

Preferred polar bear habitat is said to be 50% concentration or higher over continental shelves, which describes all but the fringes of sea ice extent today, including Hudson Bay, the Southern Beaufort, and the Barents Sea.

Preferred polar bear habitat 50pc concentration_May 8 2015_PolarBearScience

However, polar bears – excellent swimmers that they are – are quite capable of utilizing areas with 15-50% sea ice concentration if necessary (Durner et al. 2004; Rode et al. 2014:79), especially when prey are plentiful.  This would account for the fact that there are still sightings of polar bears in and around northern Newfoundland (see previous post here and photo below1), where ice concentration is in the 30-50% range.

Photo with this news story (7 May 2015): "(Update) Polar bear sighting in Croque"

Photo with this news story (7 May 2015): “(Update) Polar bear sighting in Croque”

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Spring ice alarm deflated – 2015 ice now as high as 2014 & Davis Strait highest since 1971

Arctic ice extent (at 14.1mkm2) on 15 April, was virtually identical to 2014 on that date, and higher than 2006. But the record goes to Davis Strait, which recorded the highest ice extent since 1971 for the week of April 16, while the waters of Eastern Newfoundland to the south (where most harp seals have their pups) had the third highest ice extent since 1969. Lots of fat baby seals are just what polar bears need at this time of year.

Harp seal pup_DFO Newfoundland

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Challenging polar bear fearmongering about Arctic sea ice extent for March 2015

Here are some facts to counter the misinformation and fearmongering being spread via twitter by a polar bear biologist who is getting carried away with his conservation activism.

Arctic Sea ice extent March greater than PB habitat_April 12 2015

Following up on my last post, I note that Arctic regions with sea ice but not polar bears were about 0.32 mkm2 below last year’s March average extent – which means the total ice decline from 2014 (0.4 mkm2) represents only a slight decline in polar bear habitat, most of which is in the Barents Sea (and due primarily to the state of the AMO, not global warming).

Sea ice extent for the Sea of Okhotsk and Baltic Sea combined (both areas without polar bears)1 were about 0.6 mkm2 below average this year for March. Average extent for March (according to NSIDC) is 15.5 mkm2, which means this year’s extent (14.4 mkm2) was 1.1 mkm2 below average, of which less than half (0.5 mkm2) was “lost” polar bear habitat.

IUCN Polar Bear Specialist Group biologist Andrew Derocher has been saying this is a “huge loss for polar bears” (see below): rational analysis of the facts show it is not. Continue reading

Arctic sea ice extent total for March does not equal global polar bear habitat

Only half or less of the estimated 2.6% loss per decade of March sea ice extent since 1979 (Fig. 1, below) represents a decline in polar habitat. That’s because several regions with sea ice that are not home to polar bears, like the Sea of Okhotsk, are included in Arctic sea ice totals.

Figure 1. Average monthly Arctic sea ice extent for March 1979-2015, which includes ice in the Sea of Okhotsk and the Sea of Japan, a decline of 2.6% per decade. NSIDC, March summary 2015.

Figure 1. Average monthly Arctic sea ice extent for March 1979-2015 (which includes ice in the Sea of Okhotsk, the Sea of Japan, and the Baltic, where polar bears do not live), shows a decline of 2.6% per decade. NSIDC, March summary 2015.

Both the Sea of Okhotsk and northern Sea of Japan (Fig. 2) have sea ice in winter (which is included in total Arctic sea ice records) but they are not truly “Arctic” – neither is connected to the Arctic by continuous ice, even when the ice is at its maximum extent (nor is the Baltic Sea — in contrast to Hudson Bay and the east coast of North America, which are connected to the Arctic by continuous ice).

Sea of Okhotsk_1979 March marked_PolarBearScience

Figure 2. Location of the Sea of Okhotsk and Sea of Japan. Insert ice map for March 1979 from NSIDC shows it’s position relative to the Arctic proper.

That lack of connection to Arctic pack ice is probably the main reason that polar bears never colonized the Sea of Okhotsk, even though western Arctic seal species (ringed, bearded, spotted, and ribbon) and Arctic whales  (bowhead and beluga) live there. Polar bears don’t currently live in the Sea of Okhotsk and all evidence suggests they never have.

Sea ice maps show that about half of the total ice extent difference between March 1979 and March 2015 was due to a relatively large decline in sea ice cover for Sea of Okhotsk and northern Sea of Japan — regions without polar bears. Surely no reputable scientist or journalist would suggest that the “record low” maximum ice extent for 2015 has any relevance for polar bear health and survival? [or for Northwest Passage travel, for that matter] Sadly, they would.

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Polar bear habitat update – even more ice this week in the Barents Sea

Polar bear habitat is close to average for this date all over the Arctic this week. Barents Sea pack ice has increased substantially since last week and the ice in Eastern Canada is still well above average (and higher than 1979-early 1980s). Arctic ice has grown since a preemptive call for “the lowest maximum extent on record” was made by NSIDC last week — there is now at least as much ice for this date as there was in 2011 and almost as much as there was last year (2014).

Polar Bear Breaks Ice

Southern Davis Strait polar bears are out feeding on the glut of harp seals in the pack ice off Labrador and Newfoundland (discussed in detail here). One or more bears strayed a bit from the pack and ended up swimming around near the Hibernia oil platform (not far from the ice edge, although the CBC reports didn’t mention that “minor” fact), discussed in this recently updated post (with maps).

Harp seal female with nursing pup, DFO Canada.

Harp seal female with nursing pup, DFO Canada.

Ice maps and graphs below: it’s worth a look.
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Hudson Bay sea ice above average for this date – more good news for polar bears

It’s only the 4th of December and Hudson Bay ice formation is way up over late 2000s coverage for this date — and higher than 2012, which had the lowest overall September ice extent for the Arctic since 1978.

Hudson Bay freeze-up same week_Dec 4 1971_2014 w average

This means boom times for Western and Southern Hudson Bay polar bears as sea ice formation is several days to a week ahead of last year. And as I mentioned in my last post, average November ice coverage across the Arctic this year was higher than 2003. Don’t forget that 2/3’s of the world’s polar bears live in Canada (see recent status update here; map below).

Figure 4. The Davis Strait (DS) subpopulation region runs from just below the Arctic Circle at the north end to at least 470N in the south. About half of DS lays at the same latitude as Western Hudson Bay (WH). Courtesy Environment Canada.

Polar bear population status in Canada. Courtesy Environment Canada.

More maps and charts below.
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Polar bear habitat update – November 2014 average sea ice levels higher than 2003

Average polar bear habitat for November 2014 was well within two standard deviations1 and higher than 2003, according to the November report from the National Snow and Ice Data Center (line and labels added, below).

Arctic ice Nov aver_NSIDC_sm_PolarBearScience

Notice that the lowest average November level occurred in 2006not 2007 (after the second lowest September extent since 1978) and not 2012 (after the lowest September extent since 1978). Take note that the scale on the graph above does not go to zero but to a whopping ~9.5 million square km!

Quotes from the NSIDC monthy report and sea ice maps for November 2014 and 2 December 2014 below.

UPDATE 3 December 2014: CIS has issued a new ice map corrected for ice level on Hudson Bay – new map below.
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Natural selection helps polar bears adapt to sea ice variability – which means some bears die

Evolution is not just for the long-term – natural selection also goes on over short time periods. In the case of polar bears, this adaptation is almost certainly critical for its long-term survival.

Hudson Bay female with cub_Wapusk_Thorsten Milse_Gov CA

Hudson Bay female with cub Wapusk National Park, Thorsten Milse, Government of Canada

Not all polar bears are identical — that is the reality that allows natural selection to operate.

I will argue that early breakup years in Western Hudson Bay weed out individual polar bears that do not have the physiological or behavioral characteristics necessary to be useful members of the population – and that this is a good thing for the entire population.

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