11/19/2011 2:43:38 PM
Our bags are packed and we're ready to go. This is our last day on the tundra and soon our group of scientists, advocates, and educators will be scattered across North America. It's been a remarkable trip and we've witnessed first-hand the amazing diversity of the subarctic region. We've seen polar bear, gyrfalcon, arctic fox, and raven. We've been in wetland, boreal forest. and intertidal areas. We've seen unusually warm weather and, more recently, strong northern winds that brought blowing snow and white-out conditions that prompted most bears to head for cover in the willows.
The lack of sea ice on Hudson Bay has been a running concern throughout our week on the tundra. But the timing of fall freeze-up has been variable over the years. Using data from 1979 to 1994, Ian Stirling and his colleagues found no significant trend in the timing of fall freeze- up (Stirling et al. 1999, Arctic 52:294). However, in more recent years, strong evidence of progressively later freeze-up has emerged. It is still too early to tell how this year will shape up, but the ice certainly is behind schedule. The waters of Foxe Basin, to the north of Hudson Bay, are typically ice-covered this time of year. A prolonged cold period would help get the bears off shore and back to hunting seals on the sea ice. But the current trajectory is similar to the exceptionally late freeze-up dates of the past two years.
The progressively longer periods that polar bears in Western Hudson Bay spend onshore is negatively affecting their survival and reproduction. With less time to feed during the critical seal pupping season in the spring, female bears are having a hard time successfully rearing cubs. Forced to spend more time relying on their stored fat reserves in the summer and fall, subadult bears are experiencing higher rates of mortality. Yesterday, we thought we observed a dead bear on the coast, about 300m from Buggy One. When staff from Manitoba Conservation went out to investigate, they discovered it was merely a chunk of ice, strangely coloured with blood. It was certainly a relief that there was not a dead bear nearby, but whether we see them or not, we know polar bears in this population are dying as a consequence of declining sea ice conditions.
Although ice will eventually come to Hudson Bay, it's still not certain how and when that ice will form. What is more certain is that as the climate continues to warm, the ice will freeze later and melt earlier. Polar bears in Western Hudson Bay are able to cope with an amazingly diverse and variable habitat, but like all populations of wildlife, they have their biological limits. It is the hope of everyone associated with Polar Bears International that people will collectively act to reduce the environmental impact of our societies and economies. With continued climate warming, the existence of this population of polar bears becomes increasingly unsustainable. As a regular visitor to this remarkable natural area, I can look forward to returning here next year. However, once climate warming pushes polar bears out of this area, they won't be coming back.
Photos ©Craig Taylor.