Monthly Archives: September 2014

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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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

Journalists still pushing the “polar bears eat snow geese story,” as if it matters

I wrote about this issue in January (January – and journalists are still pushing it).

Courtesy NY Times, Sept. 22 2014.

Figure 1. Courtesy NY Times, Sept. 22 2014. Click to enlarge.

This month, the New York Times (September 22, 2014 James Gorman, “For Polar Bears, a Climate Change Twist”) is pushing it big-time (and so it’s been picked up elsewhere, like by the Anchorage Daily News).

Myths and misinformation about this phenomenon dispelled below.
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Polar bears are not in peril due to recent sea ice changes

To counter the misleading ploy used by the Sunday Times — of implying polar bears are in peril because of recent changes in Arctic sea ice (Sunday Times & The Australian, 21/22 Sept. 2014 Arctic ice cap in a ‘death spiral’) — I’ll go over again why the polar bear as a species is not threatened by declines in summer sea ice or even winter ice that is predominantly “thin” (first year) ice.

Polar Peril_Arctic ice cap in a death spiral_SundayTimes_Sept 21 2014_21_NWS_20_POLAR_1096592k
Graphic above from the Sunday Times, September 21, 2014
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Ian Stirling now says the polar bear that “died of climate change” last year was “in his prime”

With Barents Sea ice way above average this summer, Polar Bear Specialist Group biologist Ian Stirling now claims the old polar bear that he said died of climate change last year on Svalbard was “in his prime” and still blames the bear’s death on lack of sea ice — despite all evidence to the contrary.

UPDATE Sept. 19, 2014 typo fixed in Fig. 1 caption [sea ice low for 2012 was 3.41 m2km, not 4.1, see here.]

Figure 1. The National Snow and Ice Data Center (NSIDC) says the September minimum for 2014 is “imminent” and suggests the low may come in at 5.1 million square kilometers (far short of the 4.1 m2km low reached in 2012. About the much larger than average amount of ice around Svalbard and Franz Josef Land, they said only: “As was the case for the beginning of the month, extent remains below average in all sectors of the Arctic except for a region in the Barents Sea, east of Svalbard.”

Figure 1. The National Snow and Ice Data Center (NSIDC) says the September minimum for 2014 is “imminent” and suggests the low may come in at 5.1 million square kilometers (far short of the 4.1 3.41 m2km low reached in 2012. About the much larger than average amount of ice around Svalbard and Franz Josef Land, they said only: “As was the case for the beginning of the month, extent remains below average in all sectors of the Arctic except for a region in the Barents Sea, east of Svalbard.”

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Polar bear attacks on humans – an evolutionary perspective

What with polar bear populations higher than they were 50 years ago and with many bears onshore during the ice-free season, a few polar bear attacks are to be expected – but how does the behaviour that drives those attacks compare with their closest evolutionary cousin, the grizzly?

Polar bear grizzly profiles_composite_Sept 15

I’ve done some summer reading on this topic, which I’ve summarized below. The results may surprise you.
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Andrew Derocher raises the “starving polar bears” issue in DailyMail interview

In what looks like a follow-up to last week’s CBC documentary, The Politics of Polar Bears, the London (UK) based DailyMail published interviews with polar bear biologists Mitch Taylor and Andrew Derocher (September 9, 2014).

The CBC film did have a one scientist vs. another” flavor about it and this article definitely echoes that approach. My comments below on Derocher’s insinuations and questions about starving bears and global warming.
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M’Clintock polar bear survey’s first year plagued by fog in an area thick with heavy ice

“Blizzards, we had fog — we had to sleep in the helicopter, on the sea ice one night, because we couldn’t fly anywhere,” Markus Dyck, senior polar bear biologist with the GN, told Nunatsiaq News Sept. 5.”

Polar bear with dart_bear_570_2012 Kane Basin_M Dyck photo

Fog was the theme of polar bear research this summer in Queen Maud Gulf, otherwise known as the M’Clintock Channel polar bear subpopulation region.

The ice has been heavy in that region as well, according to a the National Snow and Ice Data Center (NSIDC) and reported yesterday in another story (Heavy pack ice in NW Passage ice creates tough conditions this year: Pack ice clogs Queen Maud Gulf).

For maps showing where M’Clintock Channel and Queen Maud Gulf actually are, see the maps — and more quotes — below.
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Tracking polar bears in the Beaufort Sea – August 2014 map

Here is the August 2014 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here).

The USGS track map for August 2014 is copied below (Fig. 1).

Compare this to July’s map (Fig. 4). The 20 bears from May (down to 13 in June) are now down to 11. All seven of the bears outfitted with glue-on satellite transmitters in April [either males or subadult animals] have either moved out of the area or their tags have fallen off or stopped transmitting. This means that all of the bears shown on the maps below are females.

At the end of August, nearing the minimum extent of ice for this year, seven bears were on the ice and only four were on land.
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Polar Bears International responds to “The Politics of Polar Bears”

Well, sort of — what they did was provide a logical fallacy reply to an almost incoherent comment by a PBI Facebook supporter who had watched the documentary and complained of bias (such a predictable response).

See what you think, screen-cap below (taken September 3, 2014 at about 2PM Pacific Time.
[UPDATE added September 4, 2014 at 8:30PM Pacific, see below]

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