Tag Archives: ice loss

Polar bear no closer to extinction than it was 18 years ago as Arctic sea ice resists ‘tipping point’

All predictions of disaster aside, in fact the polar bear is no closer to extinction than it was in 2005 as Arctic sea ice again steadfastly resists slipping past a catastrophic ‘tipping point’ — or the ‘death spiral’, as some chicken-littles continue to call it.

In fact, the summer sea ice trend has been pretty much flat since 2007, with ice covering about 42% less area than it had done in 1979, yet polar bears in many regions are doing better now than they were in 2005, especially in Davis Strait, the Barents and Chukchi Seas and the Canadian Arctic Archipelago.

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Alaska waters with no sea ice are not a problem for Pacific walrus or polar bears

One of two alarming headlines that caught my eye this week was the ‘news’ on Monday that the waters off Alaska were now ice-free because of climate change, courtesy a story in the online media outlet Mashable that was later picked up by The Weather Channel and the UK mainstream paper The Independent. In addition, a large number of mainstream news outlets, including the New York Times and Newsweek, have reported that walruses came ashore this year at Point Lay, Alaska two weeks earlier than any year since 2007.

No one claimed this late July onshore movement of walruses was the beginning of the end of walruses but it was still blamed on human-caused climate change because it was associated with the  aforementioned ice loss in Alaska.

Walrus at Point Lay from trail camera in 2015 USFWS

Neither event was truly ‘news’. Moreover, neither an ice-free Alaska in early August or walruses onshore two weeks earlier than 2017 will have any negative impact on local polar bear or walrus populations, whether due to human-caused climate change or natural variation. Well-fed polar bears everywhere are quite capable of going 4-5 months without food in the summer and a few thousand walruses at Point Lay will feed happily from this shore-based haulout for a few days to a few weeks as they have done many summers since 2007 before moving on to other Chukchi Sea beach locations – although the ‘leaving’ events never seem to get any media attention. Walruses will haul out on beaches in Alaska and Russia until the ice returns in October.

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Spring feeding for polar bears is over – sea ice levels are now largely irrelevant

Polar bears in virtually all regions will now have finished their intensive spring feeding, which means sea ice levels are no longer an issue. A few additional seals won’t make much difference to a bear’s condition at this point, except perhaps for young bears that haven’t had a chance to feed as heavily as necessary over the spring due to inexperience or competition.

Polar bear feeding by season simple_Nov 29 2015

The only seals available on the ice for polar bears to hunt in early July through October are predator-savvy adults and subadults. But since the condition of the sea ice makes escape so much easier for the seals to escape, most bears that continue to hunt are unsuccessful – and that’s been true since the 1970s. So much for the public hand-wringing over the loss of summer sea ice on behalf of polar bear survival!

Polar bears in most areas of the Arctic are at their fattest by late June. They are well prepared to go without food for a few months if necessary – a summer fast is normal for polar bears, even for those that spend their time on the sea ice.

Putting on hundreds of pounds of fat in the spring to last through periods of food scarcity later in the year (at the height of summer and over the winter) is the evolutionary adaptation that has allowed polar bears to live successfully in the Arctic.
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