Anthropogenic global warming is occurring more rapidly in the Arctic than elsewhere and has already caused significant negative effects on sea ice-dependent species such as the polar bear. In this special presentation, Dr. Gregory Thiemann, Faculty of Environmental Studies at York University in Toronto, will discuss recent and ongoing research on the effects of climate change on polar bears, their habitat, and their prey. Although climate change is ultimately expected to negatively affect polar bears throughout their circumpolar range, the timing, magnitude and precise nature of climate-driven effects are difficult to predict. Nevertheless, quantitative estimates of the rate and magnitude of population declines are often required before meaningful conservation action can occur. Polar bears are likely to become more imperiled in the coming decades, and specific ecological factors make polar bears especially sensitive to climatic changes. Among the most profound changes in Arctic ecosystems are expected reductions in the availability of marine mammals, the primary prey of polar bears. Reduced foraging opportunities will ultimately reduce the ability of individual polar bears to survive and reproduce. However, gaps in our understanding of polar bear/habitat relationships create opportunities for ex situ research that will be critically important for understanding (and conserving) polar bears in the wild.