According to sea ice experts, winter sea ice habitat for polar bears is not expected to decline at all by 2050 and the critical spring sea ice that polar bears need for gorging on young seals and for mating is not predicted to change much (Durner et al. 2007, 2009), which is why computer modelled predictions about the dire future for polar bears only assessed the potential future effects of declining summer sea ice (e.g. Amstrup et al. 2007; Stirling and Derocher 2012). Note spring is April-June.
See if that fact is clear in the interview responses by out-spoken polar bear biologists that has just been published in the polar bear portion (“Beyond the polar bear”) of this year’s University of Alberta magazine spring climate change feature. If you can get past the “canaries in the coal mine” opener…
Sarah Pratt (Interviewer): When I talk to researchers about climate change, they repeatedly use the term “canary in the coal mine.” Is that how you see polar bears: as a species that is an early indicator of changes in our climate?
Andrew Derocher (U of A biologist): Yes, that’s exactly what’s happening. They are big, furry, meat-eating canaries. [laughs] I always say it’s a simple story. It all comes down to the No. 1 concern globally: habitat loss. We lose the sea ice, we lose the bears. This is not an issue about polar bears; really, it’s a global issue.
Ian Stirling (UA biologist, retired): I would add that we are outrageously attacked on a regular basis by climate deniers. I think what the deniers don’t like about the polar bear studies is that the relationships are so clear: polar bears need ice to hunt seals. [my bold]
Must-read related posts:
Amstrup, S.C., Marcot, B.G. and Douglas, D.C. 2007. Forecasting the rangewide status of polar bears at selected times in the 21st century. Administrative Report, US Geological Survey. Reston, Virginia.
Durner, G.M., Douglas, D.C., Nielson, R.M., Amstrup, S.C., McDonald, T.L. and 12 others. 2007. Predicting 21st-century polar bear habitat distribution from global climate models. Administrative Report, US Geological Survey. Reston, Virginia.
Durner, G.M., Douglas, D.C., Nielson, R.M., Amstrup, S.C., McDonald, T.L. and 12 others. 2009. Predicting 21st-century polar bear habitat distribution from global climate models. Ecological Monographs 79: 25–58.
Stirling, I. and Derocher, A.E. 2012. Effects of climate warming on polar bears: a review of the evidence. Global Change Biology 18(9): 2694–2706.