Tag Archives: Hudson Bay

About the time I asked a challenging question at a global warming workshop

When you really want to challenge a speaker at a scientific meeting or public lecture, deciding what’s the best question to ask is often difficult. Here’s an example that might inspire you.

In 2009, I asked polar bear biologist Lily Peacock what appeared to be an innocuous question about Foxe Basin sea ice1 at a scientific workshop that got everyone’s attention.

The question — and the reaction — might surprise you.

Arctic sea ice 2009 vs 2014 NSIDC BIST Foxe Basin marked_PolarBearScience Continue reading

Foxe Basin and Hudson Bay have more than average polar bear hunting habitat

This is shaping up to be a banner year for polar bears in Foxe Basin (central Canada), with more ice in this region than there’s been since 1992. Hudson Bay still has a large patch of thick first year ice, more than there has been at this date since 2009, which was a late breakup year.

Hudson Bay Foxe Basin ice map Aug 7 2014 labeled_sm

Ice maps and charts below tell the story.
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How long have polar bears – and people – lived around Hudson Bay?

I came across a story in the news yesterday about the discovery of an archaeological site in northeastern Manitoba that brings to mind a post I wrote back in November 2012 on the geological and archaeological history of Hudson Bay.

As I noted then, most of the archaeological sites found on or near the coast of Hudson Bay are about 1,000 years old or less – and this new site fits that pattern perfectly.

Hubbard Point Location Map with summer core area v1

A news report at the CBC (June 30, 2014) carried this description of the find, at a site called Hubbard Point, which sounds like it could yield polar bear remains: Continue reading

Polar bear habitat update, end of November 2013

Freeze-up in the Arctic (~October-November) is important to polar bears because for those animals that have spent the ice-free period on shore (not all do), it marks the end of their summer fast — they can finally resume seal hunting.

Polar bears in the most southern regions, like Southern Hudson Bay, Western Hudson Bay, and Davis Strait (see Fig. 1), routinely experience the longest ice-free period. As these bears all spend the summer on shore, they appreciate a timely return of the ice.

 Figure 1. Polar bear subpopulations defined by the IUCN Polar Bear Specialist Group (PBSG), with a few extra labels added. I’ve rotated the original map 90 degrees (right) to make it easier to relate to the ice maps below. WH is Western Hudson Bay. Courtesy PBSG.  Click to enlarge.

Figure 1. Polar bear subpopulations defined by the IUCN Polar Bear Specialist Group (PBSG), with a few extra labels added. I’ve rotated the original map 90 degrees (right) to make it easier to relate to the ice maps below. WH is Western Hudson Bay; SB is Southern Beaufort. Courtesy PBSG. Click to enlarge.

Southern Hudson Bay bear populations routinely experience an ice-free season that is just as long as it is for Western Hudson Bay bears. However, Southern Hudson Bay polar bears numbers have remained stable over the last 30 years. Some folks insist that Western Hudson Bay bear numbers are shrinking to a worrisome degree, despite indications that the recent decline could be nothing more than a return to sustainable levels after a rapid population increase in the late 20th century (similar to changes documented for the Davis Strait and Barents Sea subpopulations).

Have a look at how sea ice – essential polar bear hunting habitat – has developed within these regions over the last 10 days or so (end of November 2013) and how November 2013 compares to November 1979. The ice maps tell the freeze-up story.
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Polar bear researchers still withholding Hudson Bay data

The latest polar bear propaganda emanating from The Guardian is unscientific nonsense fed to them by activist Canadian polar bear researchers: Polar bear numbers in Hudson Bay of Canada on verge of collapse.

This episode of Goldenberg’s polar bear grandstanding includes a photo caption with a totally unsubstantiated claim that some folks might call a lie:

Melting ice is cutting polar bears off from their food source in Hudson Bay, and death rates have soared.

“Death rates have soared”? Where are all the bodies? Show us the starving bears!

In fact, the ice of Hudson Bay melts every summer and always has done. When it does, polar bears go ashore and live off the many inches of stored blubber they put on during their spring feasting on fat baby seals. The last three years, the open-water season has been only about two weeks longer than it was in the 1980s. There has been no steady increase but lots of variability.

Below I dismantle the rest of this transparently political posturing ahead of the international polar bear forum next week.
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Hudson Bay freeze-up has not been a day later each year since 1981

[Update Nov. 23, 2013: I've added a few comments, noted, in the text]

This is a follow-up to an earlier post, Polar bear problems in N Hudson Bay not due to late freeze-up, to counter some misinformation that’s being circulated about the history of Hudson Bay freeze-up dates.

Polar bear biologists working in Western Hudson Bay published new definitions of breakup and freeze-up earlier this year. The new method better reflects how polar bears interact with seasonal changes in sea ice on the bay.

Formerly, 50% ice coverage levels were used to assign the date when major ice change phenomena were reached each year (breakup in summer, freeze-up in fall (e.g. Gagnon and Gough 2005). The new method (Cherry et al. 2013, see discussion here) defines breakup at 30% ice coverage and freeze-up at 10%.

Cherry and colleagues had a fairly complicated method of defining 30% coverage for breakup in Western Hudson Bay. However, freeze-up in the fall is much simpler because ice always forms first along the western shore, starting in the north.

This means that the weekly graphs of ice development provided by the Canadian Ice Service for Hudson Bay, which are expressed as a percentage (just like the Cherry et al. study), can be used to compare freeze-up dates historically.

These graphs refute the absurd claim that freeze-up on Hudson Bay has been “one day later each year” over the last 30 years – an assertion repeated just the other day at PBI. Let’s take a closer look, shall we?
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Polar bear problems in N Hudson Bay not due to late freeze-up

The myth that northern Hudson Bay communities are having problems with polar bears this year because freeze-up is later than usual just won’t go away.

I discussed the well publicized craziness in Churchill last week (here and here), but there’s more. Polar bears are already leaving the shore of Northern Hudson Bay as the ice rapidly forms but I saw a story yesterday (dated late last week) that quoted a local official in Repulse Bay blaming their polar bear problems on late freeze-up.

I’ve written before about the peer-reviewed paper by polar bear researchers Seth Cherry and colleagues published earlier this year on breakup and freeze-up dates between 1991 and 2009. But perhaps the freeze-up data needs more emphasis. I’ve copied that graph again below, with notes, and added some ice maps. See for yourself.

Bottom line: A “late freeze-up” for northwestern Hudson Bay occurs when ice formation is delayed until early December or beyond. Freeze-up was nowhere near “late” this year, nor was the ice “slow to freeze.” It wasn’t last year either.
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