IUCN Polar Bear Specialist Group says its global population estimate was “a qualified
Here is the statement that the PBSG proposes to insert as a footnote in their forthcoming
Circumpolar Polar Bear Action Plan draft:
“As part of past status reports, the PBSG has traditionally estimated a range for
the total number of polar bears in the circumpolar Arctic. Since 2005, this range
has been 20-25,000. It is important to realize that this range never has been an
estimate of total abundance in a scientific sense, but simply a qualified guess given
to satisfy public demand. It is also important to note that even though we have scientifically
valid estimates for a majority of the subpopulations, some are dated. Furthermore,
there are no abundance estimates for the Arctic Basin, East Greenland, and the Russian
subpopulations. Consequently, there is either no, or only rudimentary, knowledge
to support guesses about the possible abundance of polar bears in approximately half
the areas they occupy. Thus, the range given for total global population should be
viewed with great caution as it cannot be used to assess population trend over the
long term.” [my bold]
So, the global estimates were “…simply a qualified guess given to satisfy public
demand” and according to this statement, were never meant to be considered scientific
estimates, despite what they were called, the scientific group that issued them,
and how they were used (see footnote below).
All this glosses over what I think is a critical point: none of these ‘global population
estimates’ (from 2001 onward) came anywhere close to being estimates of the actual
world population size of polar bears (regardless of how scientifically inaccurate
they might have been) — rather, they were estimates of only the subpopulations that
Arctic biologists have tried to count.
For example, the PBSG’s most recent global estimate (range 13,071-24,238) ignores
five very large subpopulation regions which between them potentially contain 1/3
as many additional bears as the official estimate includes (see map below). The PBSG
effectively gives them each an estimate of zero.
Figure 1. Based on previous PBSG estimates and other research, there may be ~6,000-9,000
(perhaps less but maybe more) bears living in the regions marked in black that are
not included in the most recent PBSG “global population estimate” – their population
estimates are “zero.” CS, Chukchi Sea; LS, Laptev Sea; KS, Kara Sea; EG, East Greenland;
AB, Arctic Basin.