The Committee on the Status of Endangered Wildlife in Canada has just decided that while Canada’s 15,000 polar bears are threatened by climate change they are not in immediate danger. The Committee found that numbers are decreasing in some places and increasing in others.
Hence polar bears are to remain a ’species of special concern’ rather than an ‘endangered species’. But that does not mean that all of us and the Canadian Government in particular can relax. The classification requires the Government to take legislative action.
Canada’s environment minister, John Baird, is obliged to accept the government-commissioned report’s findings and address threats to the animal’s survival, including climate change.But a management plan for Canada’s polar bears will not be required until 2014 - by which time some scientists believe the summer sea ice in the Arctic may have completely disappeared.
Some scientists say that the Arctic could be ice-free by 2013. Ice free of course does not mean ice free all the year round. Rather it refers to the state of affairs in September leading into the fall equinox. This graph shows the progressive loss of ice through the summer.
Frankly I’m not sure how important the Arctic sea ice is to the survival of the polar bear. I’m not aware of anyone who is expert in the subject predicting their complete demise, but predictions such as this one of a 40% reduction of their summer habitat are common and concerning. It seems that the Canadian Committee didn’t know either. Meanwhile Americans are still paying big bucks to hunt polar bears while their government makes up its mind whether the species is endangered or not.
It could be that the hooded seal and the narwhal are in even more trouble than the polar bear. But the article ends with the usual urging about mitigating global warming;
Researchers believe conservation measures may help these species, but the only real solution is to tackle the sources behind global warming.
The graph below shows the trend line of the loss of Arctic sea ice. Can you see it coming back to pre-1980 levels any time soon?
Bear in mind that this graph only shows area. The mass of the ice sheet has reduced by about 80% since the 1960s and the thickness from about 3.5 metres to about a metre.
I can already see how Andrew Bolt will be reporting this.
frankly I’m surprised we’ve got any polar bears left, due to fisheries exploitation.
The Arctic icepack has probably been absent in summer several times since the last glacial, but the bears are still there. If it did all melt, the seals would have to give birth on land instead of endless ice flows. The bears would find seals much easier, and bears swim pretty good distances too. A much nastier prospect for the seals, but I guess seals arent as charismatic?
Just how is Ottawa going to legislate to stop ice melting anyway? King Canute wouldn’t have thought he could.
wilful, I’ll try to avoid knowing what Bolt does with it. There are so many throwaway lines about polar bears disappearing that I thought we should be aware of the latest thinking.
Bill, these Arizona student notes suggest that the temperature was perhaps 1-2C warmer in 3000-5000 BC. It was also 1-2C warmer in the last interglacial, the Eemian.
Wikipedia has a quite extensive entry on polar bears. It’s quite pessimistic about the long term prospects, given continues global warming.
Ottawa could clearly do better on global warming as it’s possibly the most recalcitrant country of the Kyoto signatories. But specifically on polar bears it’s hard to see what they could do beyond preventing hunting.
Forgive my ignorance, Brian, but are there any protocols in place or proposed for modifying the way species danger/extinction status is assigned because of global warming? If not, should there be?
Kim, I don’t know, but I don’t think so and you’re right, there should be.
Thanks, Brian, and for a very informative post.
I’m not a biologist. The subject was not even offered at the school I attended in the 1950s. Reading the Wikipedia entry it seems that the polar bear since it separated out from the brown bear about 200,000 years ago, has become increasingly a specialised ice animal, but it will eat literally anything and so there is some hope that it can re-adapt to an ice-free land-based habitat.
The question, I suspect, is whether the females can gain enough body weight to breed consistently and whether the young bears can get enough food to grow to be independent hunters.
Because they are cute I’m sure there will always be a zoo population, although there are complications. For months young Knut appeared on the front page of the online Der Spiegel. But the upshot is the the little bugger didn’t know he was a bear, became a psychopathic publicity seeker and now has to be given the boot.
…there is some hope that it can re-adapt to an ice-free land-based habitat…
I can’t speak specifically for bears, but there is little or no chance for the overwhelming majority of species to adapt to climate change as it is currently predicted. It’s happening too rapidly, and habitats are too fragmented.
wiful, agreed. I’d query “overwhelming majority”, but there are estimates of up to 50% or more if we don’t do something. The loss of biodiversity in reefs is perhaps the most critical and very serious, because on past evidence they do regenerate, but it takes literally millions of years.
Sure, they can walk and eat, but hunting in a forest, being white may prove a distinct disadvantage!
Dead set right, FDB. It’s obviously part of their adaptation to the ice. They clearly won’t have time to evolve into a diffent colour.
Another is that they are slower than most of the species they like to eat. Hence the trick of waiting for seals to come up for air in holes in the ice.
Kim, Brian - the IUCN are the people who make the determinations on risk of extinction. They have a well-developed set of criteria which consider - among other things - changes in population size & population range, and which assess the likely causes of those changes.
If climate change is a contributing factor to a population decline, I’d expect it would already be factored in to any IUCN deliberations.
Yeah, that’s what I’m getting at. They rely entirely on stealth and cunning to hunt, and would be reduced to scavenging without ice cover. Historically they’d fast for much of summer, or barely subsist on seaweed and roots and shellfish, even though that’s when the most “life” is around. Without winter to lie around on the sea ice lazily crunching seal skulls and gorging on blubber, they won’t get to breeding condition in decent numbers.
Clearly, they’ll also clash with human settlements, moving north as ice recedes, and that usually doesn’t work out too well!
FDB, someone’s f*cked the Wikipedia entry, so I can’t check, but are you saying that polar bears don’t hibernate? I was under the impression that the females at least built an ice cave as a nursery.
If they can sit there and feed on seals in the winter their prospects are improved immeasurably, as the joint pretty well ices over each winter, even now. The temperature would need to rise quite significantly to eliminate winter ice.
Thanks, TFA. But wouldn’t any IUCN determinations have to be adopted by nation states to have any effect? I can’t help thinking that other interests come into play. You can imagine, for example, trophy hunters lobbying to prevent the listing of the polar bear, supported perhaps by Inuit who do well out of providing paid help.
I can’t get my mind around the notion of kids growing up with the dream of some day killing a large polar bear!
Thanks for the info, TFA.
brian, there’s a distinction between adaptation and survival. Adaptation in the context we were meaning infers polar bears doing something genetically different, such as changing their coats or strategies. survival will happen for many species (hopefully more than 50%) that can migrate, or have wider tolerances, but still do essentially what they now do.
Adaptation is a partial response to normal climate change, but not to this one.
The site’s back. That was wierd. It was reduced to a silly one-liner.
Some relevant quotes:
So on that basis an extended period of summer ice free habitat is going to adversely affect the females chance of storing enough fat for the breeding cycle.
There’s more, of course, but that’s some of it in case the site disappears again. But clearly the IUCNs recommendations do need to be enacted within the relevant countries.
True, wilful. According to Wiki the polar bear can still breed with the brown bear and produce fertile offspring. Some speculate that we might have interbred with Neanderthals while we were in the process of wiping them out. It’s hardly survival!
It seems that in the US Judge Claudia Wilken has just ordered the Bush administration to make and implement its decision on the status of the polar bear by 15 May.
Kassie Siegel, climate program director with the Center for Biological Diversity said it was a huge victory for the polar bear.
You never know, the judge may have struck a blow that will save the world!