Tag Archives: Amstrup

Eemian excuses: the warm was different then, polar bears were fine

Today I’ll discuss the response by Polar Bears International representative Steven Amstrup to a comment submitted during their recent “webchat” at The Guardian (Wednesday, November 6), which had to do with the fact that polar bears survived warm periods in the geological past, particularly interglacials.

[Here’s a pdf file of all the questions that were answered by PBI staff: PBI webchat Q&A, also available here]

This is the comment (the first portion of #4 on my list), submitted by MarkBLR:

There was a paper in Science magazine last year (link …) indicating that polar bears became a distinct species about 600kya (+/- 300k years).

This means that they have survived at least two (and possibly eight) previous inter-glacials, in particular the Eemian (130kya to 110kya), when temperatures in the Arctic were 5 to 8 degrees Celcius warmer than current temperatures for several thousand years.

Note that their numbers apparently decreased significantly during the Eemian, and slowly increased as temperatures cooled, but “climate change” was not enough on its own to make them extinct. [my bold]

[We can perhaps forgive Mark for not being able to spell “Celsius” correctly, but Amstrup (see below) has no excuse. The paper in Science Mark refers to is Hailer et al. 2012, discussed in a previous post here. Note that the actual question Mark asked is not included here because Amstrup responded to this portion of his comment only]

Amstrup tries to convince Mark and other readers that polar bear resilience through Eemian warming is irrelevant to the issue of future survival, which I’ll demonstrate is not the case at all.

Here is what Amstrup had to say:
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Churchill polar bear attack shamelessly used to advance global warming agenda

I guess Suzanne Goldenberg, writing for The Guardian, just couldn’t help herself with this latest story (November 4):Polar bear attacks: scientists warn of fresh dangers in warming Arctic. Two people injured in latest attack as hungry bears deprived of access to sea ice increasingly look for food on land.

Reporting on the attack is one thing — several papers covered this over the weekend (see Featured Quote #46, posted yesterday, for links to two of them). However, Goldenberg shamelessly makes this about global warming, aided and abetted by Polar Bears International (PBI) representative Steven Amstrup, a claim that doesn’t hold up to even minor scrutiny.

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Guest post: How ‘science’ counts bears

This essay by Dr. Jim Steele, professor emeritus, San Francisco State University, is reblogged from a July 3 2013 post at WUWT post, with Dr. Steele’s permission. I am not a field biologist and have never done a mark-recapture study but Dr. Steele has. His perspective on the way polar bear biologists count bears and estimate survival in the Southern Beaufort is a perfect companion to yesterday’s post, a related post that I’ll put up later this week, and this one from December, among others. I’ve added links to the references cited in this essay where they are available, as is my custom. See the original post for Jim’s responses to comments and questions.

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Guest post by Jim Steele   “How ‘science’ counts bears”

The Inuit claim “it is the time of the most polar bears.” By synthesizing their community’s observations they have demonstrated a greater accuracy counting Bowhead whales and polar bears than the models of credentialed scientists. To estimate correctly, it takes a village. In contrast the “mark and recapture” study, which claimed the polar bears along South Beaufort Sea were victims of catastrophic global warming and threatened with extinction, relied on the subjective decisions of a handful of modelers.

In mark and recapture studies, the estimate of population abundance is skewed by the estimate of survival. For example, acknowledging the great uncertainty in his calculations of survival, in his earlier studies polar beat expert Steven Amstrup reported three different population estimates for bears along the South Beaufort Sea. If he assumed the adult bears had an 82% chance of surviving into the next year, the models calculated there were 1301 bears. If survivorship was 88%, the abundance climbed to 1776 bears. If he estimated survivorship at a more robust 94%, then polar bear abundance climbed to 2490.1 Thus depending on estimated survival rates, a mark-and-recapture study may conclude that the population has doubled, or that it has suddenly crashed.

Here are the simplified basics of estimating survival.

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Cannibalism update and insight on the timing of media hype

In my last post, I went over some of the spin and misrepresentation of fact contained in the claim by leading polar bear biologists Steven Amstrup, Ian Stirling and Andrew Derocher (Amstrup et al. 2006; Stirling and Derocher 2012) that cannibalism is on the increase because of the effects of global warming on Arctic sea ice.

I’ve had an opportunity to follow up on three points that puzzled me. Three relate to the Amstrup et al. paper that described three cases of cannibalism in the southeastern Beaufort Sea in 2004 and one to the incidents in western Hudson Bay in 2009. In the process, I found at least three more misrepresentations of fact and gained some insight on why these incidents of cannibalism were hyped so enthusiastically when they were. Continue reading

Cannibalism in polar bears: spin and misrepresentation of fact galore

In my next to last post, I discussed some of the anecdotal reports of den collapses included in the peer-reviewed summary of facts presented by biologists Ian Stirling and Andrew Derocher (2012) that supposedly support the premise that global warming is already having an impact on polar bear populations (discussed previously here, here, and here), prophesied to be even greater in the future. While they admit that such reports are not based on scientific studies, they nevertheless include them in their published list of global warming impacts, and not surprisingly, that is how others have interpreted them.

The same is true for their treatment of the phenomenon of cannibalism in polar bears. In that same paper, Stirling and Derocher (2012:2701) have a section called “Anecdotal observations consistent with predictions of the effects of climate warming.” This section begins with a discussion of cannibalism:

“There have been several well-publicized observations that are consistent with predictions of the effects of climate warming on polar bears, but cannot be statistically linked. For example, intraspecific aggression and cannibalism were predicted to increase in polar bears with climate warming (Derocher et al. 2004, Table 1). Observations of infanticide and cannibalism by thin adult males on land during the open water period have been documented (e.g., Lunn & Stenhouse, 1985; Derocher & Wiig, 1999; Amstrup et al., 2006; Stone & Derocher 2007). Such events have been known to occur for many years and, although their significance is unclear, there is some evidence suggesting the frequency of occurrence is increasing in areas where bears fast on land for extended periods. ” [my bold]

And this is the evidence for the supposed increase in occurrence:

“For example, in late summer and autumn 2010 [sic], there were eight observations of cannibalism on the western coast of Hudson Bay compared to one or two in the previous 5 years (I. Stirling, unpublished data).” [my bold; 2010 should be 2009 – more on this later.]

Were these observations of cannibalism made by polar bear researchers or someone else? Were there as many observers in the area in each of the five years prior to the year they occurred, as there were when these incidents were observed? We don’t know, because it’s unpublished data.

Stirling and Derocher have again included critical information in their list of facts that has not been published. I guess I’ll have to add “evidence for cannibalism” to my previous list of “Critical evidence on polar bears in W. Hudson Bay is unpublished” (see also “Stirling and Derocher’s sea ice trick) [there is more information available, but it’s not from peer-reviewed sources – more on this below]

In this post, I take a look at some of the evidence that is published, some of the media interviews and reports that followed, and the information that came from a press release issued by an advocate group. I’ve made a table summarizing the details of all recent papers and reported incidents, and some of them are described in more detail. In a footnote, I have a brief summary of why polar bears kill and eat each other.

These details reveal some rather shocking evidence of scientists misrepresenting evidence – in their peer-reviewed papers and in interviews with the media – and bathing their global warming prophesies in the blood-lust of cannibalism. It’s past time to shine a big bright light on the cannibal issue, so pardon the length of this post.

[See followup post April 19 here]

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Record low sea ice extent and what it means for polar bears…

On Aug. 27, 2012 sea ice extent dipped below the yearly minimum extent reached in 2007.

The sea ice at this point, a five-day average, was 4.1 million km squared and the lowest point reached since satellite records began in 1979. The National Snow and Ice Data Center (NSIDC) thought it was important enough to issue a press release.

There are sure to be more than a few media-hungry folks who will be moaning about the fate of the poor polar bears because of this report. Before people get too hysterical, a bit of rational perspective might be helpful.

Keep in mind that 4.1 m sq. km (Fig. 5) is about the size of Greenland (2.166 m km2) plus Mexico (1.972 m km2), or about the size of India (3.287 m km2) plus Pakistan (0.809 m km2), figures from Wikipedia.

It may be a ‘record’ low, but it’s still a lot of ice: 4.1 m km2 is not anywhere close to an ‘ice-free’ Arctic!

Arctic sea ice melts – or gets pushed out of the Arctic and then melts – every year, leaving various amounts behind. The ice lingering at mid-September adds to next year’s ‘multiyear’ ice.

The maximum extent is usually reached mid-to-late March. Have a look at how this ‘low extent’ developed from the March maximum this year. Even if you’ve looked at some of these maps, you may not have looked at them one after the other. I’ll compare these to the fall maps for 2007, after the Sept. minimum and discuss these in relation to polar bear habitat. Contineu reading