Polar Bears and Climate Change
In March 2009 delegates from the US, Canada, Russia, Greenland and Norway met in Norway for the first meeting of its kind for 25 years and officially recognised that the greatest threat to polar bears has shifted from hunting to climate change.
The polar ice cap lies at the centre of the Arctic sea, extending 500 miles from the north pole. The rest of the Arctic sea only freezes for a part of the year so that during the winter time the area of ice more than doubles. This crust of ice, called “pack ice”, is where the polar bears like to hunt during the winter. Every year between June and October this ice melts. However global warming has resulted in there being about 15% less ice than there was 20 years ago.
Sea ice extent in December 2014 averaged 12.52 million square kilometers (4.83 million square miles). This is 540,000 square kilometers (208,495 square miles) below the 1981 to 2010 long-term average of 13.06 million square kilometers (5.04 million square miles) and 500,000 square kilometers (193,051 square miles) above the record low for the month observed in 2010.
Polar bears hunt near to the edge of the pack ice where it is thinner so that they can catch seals. They only need to eat one seal every 4 to 5 days but finding food is becoming more of a problem for polar bears as the area of pack ice gets smaller. Every year the winter time shortens, the water freezes later and the summer returns earlier, melting the ice. Its not that polar bears can’t live on land - they do, but they need to eat and the main place to find food is on the ice!
During June to October the sea ice melts and the bears are unable to hunt seals until it freezes over again. They are capable of fasting but longer times of fasting mean they are going hungry and are less likely to survive. The lack of food has also caused a drop in the birth rate. The hungrier they are, the more aggressive they become which is particularly an issue in Hudson Bay where polar bears and people come in close contact with one another.
Polar bears are excellent swimmers indeed and 15 miles for them poses no problem at all. However, in recent years they have been forced to to swim longer distances between ice floes sometimes swimming up to 60 miles across open sea to find an ice platform from which to hunt. This can leave the polar bears feeling exhausted and vulnerable to hypothermia. They can even drown if they are caught up in a storm so far from the ice pack or land.Read More: The Future