Susan Crockford, Special to Financial Post (republished at WUWT with permission from the author)
Polar bears are a conservation success story. However, you’d never know that from the output of polar bear researchers, who lately seem to have forgotten that the most crucial part of their job is the unbiased collection and presentation of scientific data.
The most recent example of this disturbing conduct came to light this fall. A new peer-reviewed paper hyped by the media was published by a research team that included several senior biologists belonging to the Polar Bear Specialist Group (PBSG). The PBSG was formed to summarize information mandated by the 1973 Arctic treaty to protect polar bears from overhunting.
Co-authors of the new paper included American PBSG members Steven Amstrup and Eric Regehr, as well as Canadian members Ian Stirling and Andrew Derocher. The researchers took population estimates from a previous study (conducted 2001-2006) and added four years of new data (2007-2010). They used a computer model, developed by lead author Jeff Bromaghin, to suggest that a severe decline had occurred from 2004 to 2006, with a modest recovery from 2007 to 2010. The size of the polar bear population in 2010 was estimated at about 900 bears (range 606-1,212), a drop of about 40% from the 2006 estimate of 1,526 (range 1,211-1,841).
However, the polar bear researchers knew before starting their new field work in 2007 that the 2004-2006 polar bear population crash had occurred, and they knew why: Sea ice in the Southern Beaufort was unusually thick in the mid-2000s during the critical spring feeding period. Periodic thick spring ice is a phenomenon unique to this region and is known to have occurred every decade since at least the 1960s.
During springs with thick sea ice, ringed seals (polar bears’ primary prey) either moved elsewhere to have their pups or were harder to find. Every time this happened, the food scarcity caused wide-spread starvation among polar bears – mothers with cubs and sub-adult bears were especially hard-hit.
Thick spring ice conditions in 1974, for example, were just as severe as in 2004-2006, and a similar crash in polar bear numbers occurred. More importantly, the 1970s polar bear population decline was followed by a rebound in numbers, a fact known to at least one of those involved in the recent study (Stirling).
The authors had to have realized a cut-off date of 2010 would produce a misleadingly-low population estimate
So why did the authors terminate their study period at 2010, when data from field work was available until 2013 (a fact evident from another paper)? They must have known that cubs born in 2007, when survival of bears began to improve, would not have been old enough to produce cubs themselves by 2010. The authors had to have realized a cut-off date of 2010 would produce a misleadingly low population estimate.
It is apparent that the polar bear population indeed recovered because, in 2012, a different survey conducted by the U.S. Fish and Wildlife Service found numbers were higher than they had been since 2002. This critical fact was missing from the new paper, its press release, and interview statements made by some of the co-authors.
It was made clear, however, that the artificially low estimate of 900 bears would be used in the 2015 PBSG population status assessment for their parent organization, the International Union for Conservation of Nature (IUCN), to include in its next Red List of Threatened and Endangered Species. This provides a probable rationale for why the polar bear study end date was set at 2010 rather than 2013.
We know that PBSG biologists are under the gun – they have until June 2015 to come up with a new assessment for the IUCN. Polar bears are not considered threatened with extinction by any measure used by the IUCN except predicted (future) threats from global warming, but the scientific veracity of those predicted threats has now been called into question.
It turns out that the population models used by the U.S. to list polar bears as “threatened” in 2008, developed with strong input from long-standing PBSG member Steven Amstrup, were heavily criticized by IUCN modelling experts. The PBSG has been told that Amstrup’s model results will not be accepted as support for the next IUCN Red List assessment. In addition, all sea ice predictive models are now acknowledged to be unreliable over future 10-20 year periods.
This means that if the PBSG cannot build a completely new computer model that predicts a decline in population of at least 30% over the next 30-36 years, and which takes uncertainties of predicted sea ice declines into account, polar bears will be downgraded by the IUCN to a conservation status of ‘least concern’ or even ‘data deficient.’ Records show neither of those outcomes is acceptable to the PBSG.
It appears that in an effort to ensure a desired result for the 2015 IUCN Red List assessment, data utilized for the Southern Beaufort polar bear study was cherry-picked to create an anomalously low population estimate and an exaggerated declining trend. In short, prominent PBSG biologists seem determined to keep polar bears listed as “vulnerable” to extinction (IUCN-equivalent of “threatened”) at all costs.
We admire polar bear biologists for their professional dedication to this iconic species, and rightly so. However, while it’s understandable that polar bear biologists are conservation-minded, the public and policy makers need them to be scientists first and advocates for polar bear protection second. Polar bears are currently doing well – data shenanigans to keep them classified as “threatened” undermine the whole point of doing science.
Susan Crockford is a zoologist and an adjunct professor at the University of Victoria. She also writes a science blog about polar bears: www.polarbearscience.com