We don't really know.
Despite the claims of a population boom, there is no definitive evidence to know how many polar bears there were "to begin with." One can't scientifically determine an end result with a variable starting point.
Polar Bears International asked
Dr. Steven C. Amstrup, USGS polar bear project leader for 30 years the following question:
Q: Why all the fuss about polar bears? Aren't their populations increasing: in fact, booming?
A: One of the most frequent myths we hear about polar bears is that their numbers are increasing and have, in fact, more than doubled over the past thirty years. Tales about how many polar bears there used to be (with claims as low as 5,000 in the 1960s) are undocumented, but cited over and over again. Yet no one I know can come up with a legitimate source for these numbers.
PBI's official statement regarding a polar bear population boom:
A persistent myth to the contrary, polar bear numbers are NOT increasing.
An excellent article, by Peter Dykstra, in the Summer 2008 edition of Society of Environmental Journalists starts documenting all of the unfounded claims:
- In a May 20 Los Angeles Times opinion piece, Jonah Goldberg took a
whack at what he sees as quasi-religious overtones to conservation.
Part of his backup? "Never mind that polar bears are in fact thriving
— their numbers have quadrupled in the last 50 years."
- James Taylor of the Heartland Institute cited a London Daily
Telegraph article that "confirmed the ongoing polar bear population
explosion" in a Sept 11, 2007, blog.
- But the March 9, 2007, story that Taylor referenced actually makes no
mention of global bear populations — quoting one scientist as
observing strong growth in one local population, in Davis Strait; and
another scientist reporting global warming-related declines in the
local population in Hudson's Bay.
- Taylor adds a new number into the mix from a March 26, 2008, posting
at the Heartland site: "The global polar bear population has doubled
since 1970, despite legal polar bear hunting."
A May 12 New York Post op-ed piece by S.T. Karnick introduces still
another number — this time with a source:
"The world polar-bear population is at a modern high — and growing.
Mitch Taylor, a polar-bear biologist with Canada's Federal Provincial
Polar Bear Technical Committee, notes that the bears now number about
24,000 — up about 40 percent from 1974, when fears arose about the
bear's ability to survive overhunting by Canadian Eskimos and
aboriginals."
- From James Delingpole, a Times of London blogger, similar numbers,
but different dates. And no source. "In 1950, let us not forget,
there were about 5,000 polar bears. Now there are 25,000."
The article first extrapolates origins of the 5,000 number. Bjorn Lomborg's 2007 book, Cool It: The Skeptical Environmentalist's Guide to Global Warming." The book said, there were about 5,000. What was the footnote? "Krauss, 2006."
Clifford Krauss, a reporter for The New York Times, who wrote on May 27, 2006, about the conflict between polar bear protectors and trophy hunters: "Other experts see a healthier population. They note that there are more than 20,000 polar bears roaming the Arctic, compared to as few as 5,000 40 years ago." But he couldn't recall his source. He just said that number is widley accepted.
As we all know, Argumentum Ad Populum is a logical fallacy.
More commentary from Dr. Amstrup:
"How many bears were around then, we don't really know because the only studies of bears at that time were in their very early stages — people were just beginning to figure out how we might study animals scattered over the whole Arctic in difficult logistical situations. Some estimated that world population might have been as small as 5000 bears, but this was nothing more than a WAG. The scientific ability to estimate the sizes of polar bear populations has increased dramatically in recent years."
