Tag Archives: spring ice conditions

Polar bear habitat: Spring 2014 in Eastern Canada was much better than 1969

It was a good year for polar bear habitat in the southern portions of Eastern Canada this spring – surprisingly, much better than it was in 1968 through 1970. And since spring conditions are what really matter to polar bears, this is good news indeed.

Environment Canada’s Canadian Ice Service recently published a nice little summary that has some rather eye-opening graphs. These describe the conditions for polar bears in the southern Davis Strait subpopulation – the one whose population size increased so dramatically between 1974 and 2007 despite lower-than-average ice extent in some years, even while their body condition declined (see here and here).

Environment Canada - Ice maps regions at July 26 2014

[Fitting post for the second anniversary of this blog, I think – more below1]

Note that I’ve added a “Blog Archive” page that lists all of my posts, easier to browse now that there are more than 200 of them.
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Polar bears move around as sea ice habitat changes – this is what resilience looks like

Oddly, it seems some people expect polar bears to sit around and suffer (or die) when local conditions deteriorate, rather than move elsewhere.

PolarBear_2008_USGS

While there are perhaps a few places where moving is not really an option over the short term, over the long term (more than one season) polar bears are free to shift to another locale if ice conditions change (either too much ice or too little).

An announcement by the WWF last week (10 April) caught my eye, as it talked about bears moving from one area to another because of changing ice conditions — as if this was surprising, extraordinary and newsworthy. That said, at least they weren’t suggesting the bears are all going to die because of declining ice, which is a huge improvement.

See what you think of this part of the press release (below), in the context of what we know about the movement of bears between regions:

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Ian Stirling’s howler update: contradicted by scientific data

Following up on my last post (Ian Stirling’s latest howler: “the polar bear who died of climate change”), I tracked down some details contained in the original Norwegian news report but which were left out of the articles that spread the story around the world. I also found some pertinent research posted online that appears to be the work of the researchers who captured this bear in April.

Figure 1. The Norwegian newpaper, The Local (Aug. 7, 2013), identifies the location that the bear was found as “a small island near Texas Bar” (marked by the square on the above map) in the very north of Spitsbergen and states it was found on July 7 – details other reports did not bother to include. To have been 250km south of that position in April (when he was tagged), he must have left the ice near the southern tip of Spitsbergen when there was still lots of ice further north.

Figure 1. The Norwegian newspaper, The Local (Aug. 7, 2013), says the bear was found on “a small island near Texas Bar” (marked by the square on the above map) in the very north of Spitsbergen, and states it was found on July 7 – details other reports did not bother to include. [“Texas Bar” is a hut built by a Norwegian hunter in 1927]. To have been 250km south of that position in April (when he was tagged), he must have left the ice near the southern tip of Spitsbergen when there was still lots of ice further north.


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Why is it that every decade, Eastern Beaufort sea ice gets really thick?

I’ve written before about the incidents of starving polar bears in the eastern portion of the Southern Beaufort Sea (here, here, and here). For two or three years every decade since the 1960s, shorefast ice in the Eastern Beaufort (Fig. 1) has become too thick and compressed in the spring for ringed seals to maintain their breathing holes, so most or all of them presumably go elsewhere — as seals did in Greenland when ice got too thick there (Vibe 1965). With few or no seal pups born during March and April in thick ice years, some bears had a hard time finding enough food: starving bears and dying cubs were the result.

Figure 1. Eastern portion of the southern Beaufort Sea.  The communities of Tuktoyatuk (locally known as ‘Tuk’), and Sachs Harbour on southern Banks Island, have been useful starting points for polar bear research because they are accessible by plane via the larger community of Inuvik The light blue portions, e.g. along western Banks Island and the Eastern Beaufort/Yukon mainland coast, indicate shallow continental shelf areas (20 km wide in places) where extensive shorefast ice develops every winter. Main map from Beaufort Sea Partnership, inset map from Wikipedia.

Figure 1. ‘Eastern Beaufort’ (yellow square) polar bear study region.
The communities of Tuktoyatuk (locally known as ‘Tuk’), and Sachs Harbour on southern Banks Island have been used as base camps for polar bear research because they are accessible by plane via the larger community of Inuvik.
The light blue portions along western Banks Island and the Eastern Beaufort/Yukon mainland coast indicate shallow continental shelf areas (20 km wide in places) where extensive shorefast ice develops every winter.
Main map from Beaufort Sea Partnership, inset map from Wikipedia.

I’ve been trying to get my head around why this would happen in the Eastern Beaufort. Once or twice – maybe – but several times every decade? What on earth drives such a process?

So, I did some reading (actually, quite a lot of reading) and have what appears to be at least a partial answer.

All indications are that the occasional development of exceptionally thick spring ice in the Eastern Beaufort is the result of an entirely natural, cyclical phenomenon. However, some polar bear biologists are attempting to blame the latest episode (but not earlier ones) on increased amounts of open water in the Chukchi Sea during fall of the early 2000s. That doesn’t seem a plausible explanation to me, given the history of the sea ice in this region. Have a look.

Figure 2. Beaufort sea pressure ridges, spring 1949. Courtesy Wikipedia (from NOAA “At the ends of the Earth” image collection #corp1014).

Figure 2. Beaufort sea pressure ridges, spring 1949. Courtesy Wikipedia (from NOAA’s “At the ends of the Earth” image collection #corp1014).

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Cooling the polar bear spin

I’ve had quite enough of the obfuscation of facts and model-based extrapolations into the future with regards to polar bears. I’m pretty sure I’m not the only one who is interested in what polar bears are doing now and, as much as can be determined, get some understanding of what the biological, geological and evolutionary history of polar bears and their habitat looks like. Spare us the emotional media hype, icon-peddling and fear-mongering about the future — we’d just like some information about the bears!

Polar bears at the Stanley Park Zoo, Vancouver, taken with my first camera in the early 1970s.

I’ve been looking at the scientific literature produced by polar bear and Arctic seal biologists for some time and I’ve found it contains some rather interesting and potentially important facts that are being left out, glossed over, or misrepresented in statements and publications generated by polar bear advocates of all kinds. It’s past time for these issues to be brought to light and publicized in one easily-accessible, up-datable forum. Hence, PolarBearScience.com — a new blog in which I discuss the science of polar bears while throwing cold water on some of the spin. Continue reading