Tag Archives: polar bear numbers

2013 PBSG polar bear status table information in one document

As I pointed out on Valentine’s Day, the IUCN Polar Bear Specialist Group (PBSG) has released a revised population estimate for polar bears of 18,349 (range 13,071-24,238), based on a new status table posted February 14, 2014.

PBSG status-table-2013_Feb 14 2014_intro

In that February 14th post, I also pointed out that as for the 2005 and 2009/2010 status tables, the PBSG did not add up the columns and give the totals — you had to do that yourself, which is how I got the numbers above (last week, I made a couple of graphs that show changes over time in their status table estimates). Oddly enough, there is now no mention of an official global polar bear estimate anywhere on the PBSG website.

In addition — and the point of this post — is that to see the details of how and why the PBSG biologists arrived at the population estimates and the status assessments they present (with references), you have to click on the hyperlinked title of each separate subpopulation in the table. While they made a one-page black and white summary of the online colour table available as a pdf (linked at the bottom of the page), they did not make the assessment details from the status table available in pdf format.

So I did it myself, via copy/paste into a Word document that I converted to a searchable pdf, without editorial comment except that I included the totals given above and noted a few glaringly obvious omissions (see below). It took me all of 30 minutes.

I offer it here for more effective scrutiny, convenient reference and archival purposes — because the way it stands now, the online table could disappear tomorrow without any hard-copy evidence of the information hyperlinked within it.

UPDATE February 26, 2014 I checked the PBSG website this morning and the omissions I noted below that were present a few days ago have been fixed. I did not receive a reply to my email notification of the issue. An updated pdf is now available.

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Graphing polar bear population estimates over time

I’ve already commented on the 2013 update of polar bear population status released by the IUCN Polar Bear Specialist Group (PBSG).

However, I thought it might be interesting to graph the changes in global population estimates over time (from 1981-2013) — not just the actual estimates from PBSG status tables (with their min/max error ranges) but those totals plus the so-called “inaccurate” estimates that the PBSG have dropped from their accounts in recent (2005-2013) assessments: Chukchi Sea, East Greenland, Queen Elizabeth Islands (now known as the “Arctic Basin”), and Laptev Sea.

In 2001, those “inaccurate” estimates contributed 5,000-5,400 bears to the global total, but now they’re gone — no bears from those regions contribute to the official totals listed on recent PBSG status tables.

Adding those dropped estimates back into the global totals makes it possible to generate a graph in which the global estimates are truly comparable over time.

To see how the dropped estimates influenced the perception of population change over time, I’ve also graphed the estimates given by the PBSG in their status tables. I’ve combined the two into one image (Fig. 1, click to enlarge) to make comparison easy.

UPDATE 5 December 2014: Links to more recent posts relevant to this issue added below. The most recent numbers, added 31 May 2015, are here.

UPDATE 26 March 2019: See “Latest global polar bear abundance ‘best guess’ estimate is 39,000 (26,000-58,000)
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Davis Strait polar bears again: body condition declined while population increased

This is a short follow-up to my last post on Davis Strait polar bears.

Today I’ll highlight a paper published last year (Rode et al. 2012) that had three of the same co-authors as the Peacock et al. (2012) paper I discussed on Monday – Lily Peacock, Mitch Taylor, and Ian Stirling contributed to both papers. Rode et al. (2012) deals with the issue of body condition (relative degree of fatness) in polar bears vs. changing levels of sea ice over time, and if you’ll pardon the pun, adds even more weight to the conclusion that declines in summer sea ice do not necessarily spell the disaster for polar bears we have been told is inevitable.

A polar bear near Thule, NW Greenland. Note the decidedly chubby back end on this bear, who looks well prepared for winter. Photo by Robin Davies. [details at my Quote Archive, Featured Quote #6]

A polar bear in the summer of 2012 near Thule, NW Greenland (part of the Baffin Bay subpopulation). Note the decidedly chubby back end on this bear, who looks well prepared for winter. Photo by Robin Davies.
[details at my Quote Archive, Featured Quote #6]

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