Saturday, November 22, 2014

Polar Bear Numbers Decreasing

The polar bear, as we all know by now, has become the symbol of the argument over climate change. The bears were put on the threatened species list in 2008, despite the fact that their population was quite robust. The rationale for that decision is because the Arctic sea ice is decreasing and is at risk of disappearing completely during the summer months within a few decades. Since the bears spend most of their lives on the ice, this would constitute habitat loss for them and that would threaten their population due to their lack of hunting areas. This decision led to a firestorm of comments from the climate change crowd and even lawsuits. The argument has been clouded by the fact that additional counting methods have been introduced that seem to show the population is increasing.

Now, more data is coming in showing there is a lot of stress on the population. Before I continue, I am not going to say the polar bear is at risk of extinction anytime soon. Some of the 19 identified sub-populations are at risk, but not the species. There are approximately 25,000 polar bears in the Arctic, so the species is not at immediate risk.

Having said that, the trend of the polar bear population is becoming pretty clear - it is declining and we can expect even more decline in the future.

A scientific paper published in the Ecological Society of America journal Ecological Applications states the Beaufort Sea sub-population decreased by 40% between 2000 and 2010, from 1500 bears in 2001 to only 900 in 2010. Studies of all 19 sub-populations is not possible due to the remoteness of some of them and a lack of funding, but studies of 10 of the sub-populations has shown the population to be decreasing in four of them, stable in five of them and increasing in one. The population as a whole is decreasing.

The additional pressure on the population is highlighted by the situation this fall in Churchill, Manitoba, Canada. Churchill is a gathering place for one of the sub-populations in the fall as Hudson Bay begins to freeze over. They use this area as their shoving off point to go out and hunt seals and other high calorie food they need to survive the harsh winter. Except, this year there was no ice. About 800 polar bears gathered and found there was no way for them to get to their food supply. To see what this means, the size of this sub-population was about 1200 just 30 years ago. The population has dropped by one-third in only 30 years, even though there are new laws to protect them from hunting. There is legitimate fear this sub-population may disappear completely within as little as ten years.

As of today, Hudson Bay has still not frozen in the area of Churchill. Take a look at this map of the sea ice extent:
Source: Climate Change Institute

The light blue line shows the average sea ice extent for this date. Churchill is located about one-half of the way up the left side of the bay, right where there is a sharp jut-out and a little below the borderline that is shown. As you can see, this area is supposed to be iced-over by now, but it isn't. That is bad news for the bears waiting to go hunting.

Now, ask yourself, how would you like to be trapped in an area with 800 hungry polar bears? Do you think that if you were, you would come to the conclusion that climate change is not such a good idea?

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