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.

Continue reading

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.
Continue reading

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
Continue reading

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.”

Continue reading

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.
Continue reading

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.
Continue reading