Polar bears in the Canadian archipelago are losing the habitats, and could face starvation by the end of the century, according to a new study. The region has often been considered a "last refuge" for the Arctic animals, as they face increasing pressures brought about by changing climate and human settlements.
Narrow water channels and complex geographical features make measurements of sea ice in the Canadian archipelago difficult, and often inaccurate. Earlier research suggested frozen conditions in the archipelago could be more resilient to climate change than other regions of the world. New studies suggest changes in ice cover in the area, including longer ice-free periods each year, could harm populations of polar bears.
"We predict that nearly one-tenth of the world's polar bear habitat, as much as one-quarter of their global population, may undergo significant habitat loss under business-as-usual climate projections," Stephen Hamilton from University of Alberta, said.
Hamilton and his team of researchers examined projections of sea ice, snow cover and ice thickness for the archipelago for years covering 2006 to 2100. This data was then compared to computer models of the energy needs of polar bears, in order to measure the effect disappearing ice sheets have on the animal populations.
These simulations predict that by the year 2100, the Canadian archipelago will experience between two and five months each year without ice cover, conditions which are not seen in the present era. This change could result in widespread reproductive failures and starvation, as migratory patterns of species is transformed by global warming.
Female polar bears need to travel to land and fast during one portion of gestation, and if they are trapped from their migration, it could detrimentally affect pregnancies. Computer simulations predict that six months of ice-free conditions in the archipelago would result in the loss of between nine and 21 percent of adult male polar bears, due to starvation. Females and cubs would fare even worse with changing conditions, the researchers determined.
The Canadian archipelago consists of more than 30,000 islands, which sit north of the mainland. Thousands of polar bears live in the region, around one-quarter of the global population of the animals.
"Polar bears feed primarily on two species of seals - ringed seals and bearded seals - both of which they have access to from the ice, but not from the land," Hamilton said.
Ringed seals require eight inches of snow for their life cycle, and a reduction of snow depths could exacerbate food supply problems.
Study of polar bears in the Canadian archipelago and how they could be affected by global climate change was detailed in the online journal Plos One.
