Tag Archives: Hudson Bay

In 1999, climate change apparently threatened Western Hudson Bay polar bears

Now, not so much. Here is a 16- year old CBC TV special on Churchill polar bears – listen to Ian Stirling and reporter Eve Savory use the early breakup of sea ice on Hudson Bay in 1999 to hype the alarm about Western Hudson Bay polar bears. Watch Stirling in action darting and measuring bears and bemoaning the good old days of the 1980s, claiming the “bears are sending a signal from the ecosystem.

Watch this archived copy of “The Shrinking Bears of Hudson Bay and compare his claims to what has actually happened in the 16 years since then. It runs just over 15 minutes.

Climate change threatens polar bears 2_CBC 1999

“Just as the ice is shrinking in Hudson Bay, so are its polar bears. Climate change has shortened the season for winter ice, a crucial period for the bears to feast on seals and build up their fat reserves. And so, over the 18 years that wildlife biologist Ian Stirling has been studying them, the polar bears have become skinnier and their offspring fewer. In this 1999 report for CBC-TV’s The National, Stirling says once their habitat is gone, there’s nowhere else the Hudson Bay polar bears can go.” [my bold – see notes below]

Program: The National [Canadian Broadcasting Company, CBC]
Broadcast Date: Sept. 23, 1999
Duration: 16:39

Stirling has continue to make these claims since 1999, yet no updated evidence has been provided. There is no plausible evidence that the decline of polar bear numbers in Western Hudson Bay was due to sea ice changes caused by human-caused global warming (Crockford 2015) or that continued declines in condition of bears or litter size have  occurred. Note that the latest survey of Western Hudson Bay polar bears found no trend in either breakup or freeze-up dates since 2001 (Lunn et al. 2013) and that the population is now stable.

Ice coverage charts and breakup dates graph below, for context.
UPDATE ADDED – see below
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Summer habitat for most polar bears is either shoreline or sea ice in the Arctic Basin

At this time of year, sea ice extent numbers are meaningless for polar bears.  The extreme low September minimum of 2012 – when masses of polar bears didn’t die – showed rational people that this is true. Even the low 2007 summer extent, which hit earlier in the season than 2012, had little to no negative impact.

Greenland W coast_Female w cubs_2006_Mads Heide-Jorgensen_NOAA sm

In late summer, bears outside the Canadian Archipelago either retreat to shore or stay on the sea ice as it retreats north into the Arctic Basin (see image below, click to enlarge).  Most bears in the Archipelago have ice year round, so life doesn’t change much. This means that it does not matter to polar bears how much area the Arctic Basin ice covers in September – for their needs, 1.0 mkm2 would be plenty.

Sea ice and summer refuges for polar bears_17 Aug 2015

Still, Southern Hudson Bay polar bears had extended hunting opportunities in July this year (whether or not they hunted successfully) and for this date, Hudson Bay had more ice remaining than any year on record. Yes, more than even 1992 but only by a few percent. See charts and maps below.

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Well-fed polar bears onshore at height of summer easily deterred by noise, CBC reports

From the CBC this morning, we have the report of a female polar bear and her cub paying a visit to an Nunavut campsite near Chesterfield Inlet in northwestern Hudson Bay, which is technically within the boundary of the Foxe Basin polar bear subpopulation.

Maggie Putulik photo, 29 July 2015 Chesterfield Inlet, Nunavut.

Maggie Putulik photo, 29 July 2015 Chesterfield Inlet, Nunavut.

These are not the desperate bear victims of global warming we have been warned about by polar bear specialists but well-fed curious ursids not averse to an easy meal if there’s one to be had. Such bears are easily deterred by a loud noise. Note this was the second visit by polar bears this Nunavut family had experienced at this location within a three-week period – two other bears had stopped by earlier. Note that ice in this region of Hudson Bay broke up earlier than usual this year yet these bears seem to be in fine condition and can expect the first fall ice of the season (freeze-up) to appear in their neighbourhood, see maps below.
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2nd highest ice coverage for Hudson Bay since 1971 at mid-August – only 1992 higher

Since 1971, there has been no year when there was as much ice left on Hudson Bay as there is this year at August 13th, except 1992 – the year when Mt. Pinatubo seemingly affected Hudson Bay ice levels but not any other region in Eastern Canada or the Beaufort Sea. Odd, that – see the graphs below.

Hudson Bay same week 13 Aug 1971-2015

Doesn’t mean that much to polar bears, since they will mostly be fasting whether they are onshore for the summer or riding the ice – they primarily live off their fat this time of year. Still, the relative ice levels are interesting because it could impact freeze-up dates later this fall, which will influence the bears’ ability to hunt before the winter fast sets in.

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Hudson Bay ice update – researchers awfully quiet about what polar bears are doing

This year 225 thousand km2 of sea ice remained on Hudson Bay at 10 August compared to 96 thousand km2 in 2009, the last late breakup year for which there are detailed ice maps and polar bear data.

Hudson Bay breakup Aug 10 2015_CIS

In 2009, most Western Hudson Bay polar bears were onshore by 22 August, just after the very last remnants of ice disappeared (see map below). This year? The remaining ice is further east, in Southern Hudson Bay territory.  Last report from a few weeks ago showed some Southern Hudson Bay bears came ashore early but past behavior suggests some bears will wait until the bitter end before they come ashore – until the very last remnants of ice disappear (Cherry et al. 2013).
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Hudson Bay, Davis Strait and Foxe Basin sea ice highest since 1992

We are seeing one of the extremes in Hudson Bay sea ice variability this year, not only in extent but in distribution of ice. Ice coverage on Hudson Bay this year at 28 July was twice what it was in 2009, the last “late” ice breakup year for which detailed ice maps are available (409 vs. 204 thousand km2), according to NSIDC MASIE ice maps. Canadian Ice Service data show 2015 coverage for the week of 30 July was the highest since 1992.

Churchill_Polar_Bear_2004-11-15 Wikipedia

The odd pattern of ice distribution presents a conundrum. Have a look at the maps and graphs below.

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Researcher says most S. Hudson Bay polar bears still on the ice, may have to swim home

More than half of Southern Hudson Bay polar bears under study are still out on the thick Hudson Bay sea ice that’s been giving Canadian Coast Guard icebreakers so much trouble.

Figure 6. James Bay polar bear female and her cub during the ice-free period. Notice how fat they both are. Courtesy Ministry of Natural Resources, News Ontario, June 2, 2009.

James Bay polar bear female and her cub on shore. Courtesy Ministry of Natural Resources, News Ontario, June 2, 2009.

As I pointed out a few days ago, most of the ice remaining on Hudson Bay is in the region used by Southern Hudson Bay polar bears. While you wouldn’t know it from the Polar Bears International “Bear Tracker” – which hasn’t been updated since 2 July – on Friday (24 July 2015) Ontario polar bear researcher Martyn Obbard used the PBI website to reveal where his study sample of polar bears are located.

Obbard posted a little essay on PBI’s “Save our sea ice!” website which had, buried near the end, the admission that on 20 July, five out of his nine Southern Hudson Bay females with satellite radio collars were still out on the ice, “far from the Ontario coast.
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