Arctic Polar Bears Shrinking as Climate Changes

New scientific research indicates that climate change has been causing polar bears to shrink over the past 100 years.  The scientists involved measured polar bear skulls from examples spanning the past century and concluded that there might be a connection between their loss in size and the loss of Arctic sea ice.  Ecosystemic changes, they added, might be stressing the polar bears to the extent that their growth is being inhibited. 

Compared to the early 20th century skulls, more recent ones were reduced in size by up to nine per cent. 

Climate Change Shrinking Polar Bears

The study on climate change and polar bears appears in the current edition of the Journal of Zoology.  “Because the ice is melting, the bears have to use much more energy to hunt their prey”, head scientist Cino Pertoldi explained.  “Imagine you have two twins - one is well fed during its growth and one is starving.  [The undernourished] one will be much smaller, because it will not have enough energy to allocate to growth.”

Spearheaded by Pertoldi, the team of researchers involved in this study included other representatives of the Department of Arctic Environment at Denmark’s Aarhus University. 

As well as reducing in size, the polar bear skulls were also recorded as having changed in shape, for reasons unknown to the team although, again, climate change could figure, specifically localised pollutants, Pertoldi suggested.

Arctic Sea Ice and Pollution

The polar bear study’s goal was to assess the animal’ habitats at two distinct moments in time, where the amounts of Arctic sea ice and pollution levels were nowhere near the same.  Pollution-wise, the emphasis was on compounds such as bromine, chlorine, iodine and fluorine.  A number of these are no longer in general use, but remain a part of certain industrial processes.

The older polar bear skulls studied were made available to the researchers by Denmark’s Zoological Museum in Copenhagen.

As far as veterinary scientist Christian Sonne was concerned, the study provided an unprecedented opportunity into how polar bears have fared over the past ten decades. 

“Polar bears are one of the most polluted mammals on the globe”, he added.

See also:

Nature Affected by Climate Change