Have you read the full
ARCTIC CLIMATE IMPACT SCIENCE report released today? It's an update to the
ARCTIC CLIMATE IMPACT ASESSMENT. Finally the scientists are beginning to understand why I have come south!
(italics mine)pg. 85
Recent analysis of the Western Hudson Bay polar bear population found a decline from
1,194 bears in 1987 to 935 bears in 2004, a reduction of about 22% (Regehr et al.
2007b). This decline appears to have been initiated by the earlier observed declines in
body condition and demographic parameters, caused by the earlier spring break-up of
sea ice (Regehr et al. 2007b). Sea ice break-up in western Hudson Bay occurred more
than 0.8 days per year earlier from 1971-2003, meaning that
by 2003, break-up was
occurring approximately 26 ± 7 days earlier than in 1971 (Gagnon and Gough 2005).
After the population decline began, it was probably aggravated by continuation of an
existing harvest which was no longer sustainable (PBSG 2006). In 2004, the
Government of Nunavut actually
increased the quota of polar bears that could be
harvested from the Western Hudson Bay population from 55 to 64, based on the
perception of communities which, due to the increased sightings of polar bears around human settlements, believed that the size of the population was increasing (Stirling and
Parkinson 2006). An alternate explanation for the increased bear sightings is that
polar
bears, nutritionally stressed due to earlier sea ice break-up, are encroaching on human
habitations in search of supplemental food (Stirling and Parkinson 2006, Regehr et al.
2007b). The PBSG (2006) advocate a precautionary approach when setting harvest
levels in a warming Arctic, and they recommend that appropriate management action be
taken in response to the decline in the Western Hudson Bay population.
pg. 89:
Outlook Several projections of polar bear habitat and population have been made as part of the
analyses to inform the USFWS decision regarding listing the polar bear on the U.S.
Endangered Species Act. Using 10 general circulation models (GCMs) that best
approximate observed trends in sea-ice loss, Durner et al. (2007) projected a
42% loss
in optimal polar bear habitat during summer in the polar basin by mid-century (Figure 2).
As the projected rates of habitat loss tend to be less than the rates observed during the
past two decades, these estimates are considered by the authors to be conservative
(Durner et al. 2007). Amstrup et al. (2007) predicted that
realization of the changes in
sea ice projected by the same 10 GCMs would mean the loss of approximately two-
thirds of the current polar bear population by mid-century.
© text 2008 WWF. All rights reserved
photograph by Eoin Harris ft. Nikki Johnson
