The usual expert advice is that:
two-thirds of the world’s polar bears — including all of those in Alaska and most of Canada’s western Arctic — will be gone by 2050. The only ones remaining, the panel warned, will be those animals inhabiting the High Arctic regions of Canada and western Greenland.
That opinion was given by the U.S. Geological Survey in a report a little more than a year ago according to an article recently reporting that more polar bears are now going hungry than they were two decades ago.
Care has to be taken about what conclusions can be drawn from the evidence. Apparently the study found that “nearly a third of the bears sampled were going without food longer than they normally would.” But this was in only one area – the Beaufort Sea which is located just north of the border between Alaska and Canada in the western Arctic.
Some visuals may help. This is the map of the Beaufort Sea:
This image shows how the ice is increasingly moving away from the coast in the western Arctic:
Those lines of course represent the maximum summer sea ice loss, usually in early autumn about mid-September. But this article puts the problem succinctly. As the years pass Arctic ice is melting earlier and forming later so that:
polar bears are left with less time on the ice to hunt for food and build up their fat stores, and increased time on land where they must fast. As their ice habitat shrinks, skinnier and hungrier polar bears face a grave challenge to their survival.
The loss of prime feeding time in the late summer and autumn is a particular issue for the female bears. In November-December they build an ice cave, give birth and then feed their young with milk generated by stored fat, emerging from the den in March-April.
The New Scientist picked up the story as a news item followed rapidly by an article by William Laurance suggesting that:
much greater danger is faced by the thousands of species – including many large, photogenic mammals – living in tropical rainforests.
He then mentions the “white lemuroid possum (Hemibelideus lemuroides), a striking animal confined to a cool mountain top in north Queensland” which no-one has seen for three years.
I think it’s a case of both/and rather than either/or.
This article by Ed Struzik explains how difficult it is to keep tabs on polar bears who have a range of up to “200,000 square kilometres” (sic) and have been known to swim 100 kilometres in 24 hours. Yet it seems clear that five of the 13 polar bear populations are declining in numbers, while only three populations are increasing. And two of those three are increasing because the Inuit have decided to decrease their hunting take.
The U.S. Geological Survey report cited at the top of the post used conservative, indeed optimistic projections of ice loss. Jo Romm at Climate Progress thinks the polar bears could be in real trouble by 2020 or 2030.
Another problem is that the staple diet of polar bears, the ringed seals, could be in trouble “because they need stable ice cover to nurse their pups in spring.” Remember that the white ice sheet in the image above includes all sea with a 15% or greater ice coverage. And that ice is becoming desperately thin. As Dr. Derocher says “no habitat, no seals; no seals, no bears.”
There is perhaps comfort in the fact that the polar bear has already survived one interglacial, the Eemian about 125kya, having evolved from the brown bear perhaps 200,000 years ago.
As against that it seems likely that the polar bear was not as specialised in terms of habitat then compared with now.
If we want to think short term, summer ice could clear from the Arctic as early as 2012.
We desperately need also to think long term, however, and Hansen has cautioned us that if CO2 levels persist at current levels for long enough we are likely to cop a temperature rise (from pre-industrial) of 2.7 to 3.7C and a sea level of 15 to 35m.
I’m afraid that with policy makers sprouting 450ppm and +2C as the guard rail but not taking actions that would bring us within a bulls roar of those inexcusably reckless targets I’ll have to keep posting on these matters while I have strength.
There’s more at Wikipedia whence come this depressing graphic:
For orientation, the Beaufort see is at the bottom while Greenland sticks out on the right side.
And here, also from Wiki, is the obligatory polar bear image:
It carries the caption:
Cubs are born helpless, and typically nurse for two and a half years.
Thankfully for mum bear, the wolves get some, but you can see that the mother bear has to do a lot of feeding in a very short time when she gets the chance.
Churchill Canada, polar bear capital of the world.
http://www.greenpeace.org/international/photosvideos/photos/polar-bears-in-churchill-in-ma-3
http://www.keyboard-culture-global-warming.com/2008/03/consequences_of_polar_ice_melting_in_northern_canada_visible_from_tundra_buggy_in_churchill_manitoba.html
Here are the key observations from the second article:
“Up until the 1970’s, when the behavior and ecological importance of polar bears led to a policy of protection, the common practice was to kill any bear which happened into town. Now, the bears are shot, not with a bullet but with a tranquilizer. Then, they are transported out of town so that they can continue to thrive yet not pose a threat to the people of Churchill.
In recent years, two key changes have occurred:
1) The time of year when the bears are visible from the tundra buggy has expanded because they emerge from the Hudson Bay ice earlier in the season; and
2) Average temperatures during the extended periods when the bears wander into town have risen so much that the tranquilized bears must be stored in a special refrigerator until they can be relocated safely.”
BBC World did a report on the bears–apparently the Canadian wildlife authorities are reporting a radical upsurge in intra-species cannibalism (if that’s the term.)
In a of Attenborough-educated citizenry it’s probably a wise thing to concentrate on the bears to raise public awareness, even if the central issue is the North Pole being killed.
BTW, Andrew Bolt was peddling a lie that the predictions for an ice-free arctic summer were made for 2008 not 2012–ergo the silly alarmists were going off halfcocked.
I wonder if the git is secretly praying that the prediction, if it comes true, to be closer 2030 than 2012?
Nickws, I haven’t had time to read Kim’s thread yet, but the straight out lie seems to be part of the denialists arsenal these days. It’s a worry that these people infest the public space. Also there has been a story going around that the winter ice is back to 1979 levels (wrong). I’ll have a post up on that one tonight.
Hannah’s dad, I’ll catch the links later, but thanks. In one of the articles I linked to it was pointed out that bears, unable to feed on the ice where people can’t see them, are heading for populated areas to scavenge. But alternative food sources are unlikely to help the females who apparently need to roughly double their weight during the late summer/autumn so that they can hole up in a den to birth and then fees the young.
So superficial impressions, and even official attempts to count, can be misleading over what is going on wrt to polar bear numbers and prospects over a period of years.
Nickws informs us that “Andrew Bolt was peddling a lie that the predictions for an ice-free arctic summer were made for 2008 not 2012…”.
Utter rubbish. Bolt is saying that some scientists and associated alarmist spoke of the arctic being ice-free in 2008. He has also spoken of others who talk about it happening in 10 years. There is no one prediction so your claim that the prediction is for 2012 is just as silly as Bolt’s (non-)claim that it was for 2008.
Of coarse, Bolt talks of this in relation to the fact that sea-ice cover in 2008 bounced back from 2007 levels and returned to more normal levels. By some readings they bounced back to 1979 levels. I noticed that the map in the article here refers to the 2007 sea ice cover..wonder why 2008 was left out? I’m sure it was just an oversight – publishing deadlines and the what.
“intra-species cannibalism (if that’s the term.)”
I’d call that a tautology.
Mark,
Here is the latest information regarding sea ice extent:
Artic Sea Ice News
In summary:
The facts on the, er, water don’t really support your position.
Declining sea ice ? Polar bears in danger ? I’m calling bullshit on this one.
——————————————-
http://www.dailytech.com/Article.aspx?newsid=13834
Thanks to a rapid rebound in recent months, global sea ice levels now equal those seen 29 years ago, when the year 1979 also drew to a close.
….
….
Why were predictions so wrong? Researchers had expected the newer sea ice, which is thinner, to be less resilient and melt easier. Instead, the thinner ice had less snow cover to insulate it from the bitterly cold air, and therefore grew much faster than expected, according to the National Snow and Ice Data Center.
In May, concerns over disappearing sea ice led the U.S. to officially list the polar bear a threatened species, over objections from experts who claimed the animal’s numbers were increasing.
I’d call that a tautology
I’d call it an oxymoron
pr “predation”
Jonno’s statement @9 cites the dailytech.com item that claims this, which itself cites data from the Arctic Research Center at University of Illinois.
The Center has issued a statement regarding that claim, pointing out that while global sea ice extent is about the same as in 1979, arctic sea ice cover has substantially diminished, offset by increase in antarctic cover.
Furthermore it points out that current arctic cover is becoming increasingly thin so overall loss of ice is substantially greater than the decreased cover indicates.
Before some idiot leaps in to claim that if antarctic ice cover is increasing it must mean that the planet is cooling, the matter was further explained here, back in 2005.
Thanks sjk and MikeM for holding the fort.
I’ve made an extended comment in a new post.
No, Herr Professor Bolt only had one source for the failed 2008 prediction, not `some’; which in his weaselly way he then implied was the entire scientific community’s prediction for an ice-free arctic
You’re given credence to predictions of 2012 or later, I assume? I mean you’re obviously informed about the non-crank science when you say there are several estimates…