Steve Amstrup has left a comment below his January 20, 2014 “starving polar bears’ article at The Conversation, which I discussed in my last post.
I’ve copied his comment below and the response to his comment that I left this morning, which is copied below his. See the entire comment sequence here.
Comment left on Jan. 23, 2014 [“15 hours ago” from 7:00 am Jan 23 2014]
• Steven Amstrup
Adjunct Professor, University of Wyoming in Laramie at University of Wyoming
I am largely out of pocket this week and hence have not had the time to follow-up on every comment that has been made in this conversation. Viewing the discussion thread, this morning, however, I see a few comments that clearly need to be corrected. So, I will take a few moments now to address them.
First, the most recent comment by Mr. Benton suggesting a “massive” recovery in September sea ice in 2013. Although Mr. Benton repeats what many other climate change deniers have stated, the truth is that there was no massive recovery in sea ice extent. The September extent in 2013 was indeed substantially greater than it was in the dramatic and record setting retreat recorded in September 2012. So sure, the ice extent was greater in 2013 than in 2012. The critical point, however, is that the ice extent in September 2013 fell almost right on the long term trend line of sea ice decline. That trend line, recall, shows that the September sea ice has been declining at greater than 12% per decade. In fact this “massive recovery” merely brought the September extent back up to what it had been in 2005. And we must remember that the 2005 extent was the all time record low September extent recorded un until then. So, the supposed “massive recovery” of 2013 is just another myth perpetuated by those who for some reason want to deny anthropogenic climate change and the affects it will have on us all. I suggest studying the abundant information on this topic at the web site of the National Snow and Ice Data Center (NSIDC).
Second, another false collection of statements by Mr. Benton. No one believes that there were only 5000 polar bears in the 1970s. Clearly some populations were at lower levels then than now, but we didn’t have anything like good estimates, and there was no agreed to estimated of 5000. Peter Dykstra wrote a very nice piece several years ago about how the climate change denier community trumped up this number (http://www.sej.org/pub/SEJournal_Excerpts_Su08.htm). Some populations did increase as a result of better hunting regulations, as I and some of my colleagues have published, BUT, the 5000 number is simply rubbish. As far as today’s best estimate of total numbers, the International Polar Bear Specialist Group has concluded that that number is between 20, 000 and 25,000. As far as the photo, I have no knowledge of how or why the photo accompanying my piece was selected. If it is a faked photo, that is unfortunate.
Third, Paul Matthews also points out the unfortunate choice of the photo chosen to accompany my written piece. Then, Mr. Matthews goes on to question my statement about the certain demise of polar bears without GHG mitigation. The fact is there is no evidence anywhere that polar bears can persist in anything like current distribution or numbers without adequate access to sea ice. Polar bears stuck on land in Hudson Bay in summer lose nearly 2 pounds of body weight for every day they are on land. Would Mr. Matthews suggest they are dieting intentionally? In the areas of the Arctic where grizzly bears occur on shore adjacent to the ice areas occupied by polar bears, those grizzly bears are among the smallest of the brown bear group and they occur at extremely low densities. In contrast, the polar bears, supported by the marine ecosystem, instead of the depauperate terrestrial system, are abundant and very large. What logic would suggest that we could force whole populations of the largest bears in the world into habitats that currently support only small numbers of small bears? There simply is no evidence that can happen. Now, could some bears in some areas find ways to survive and forestall the effects of the loss of sea ice, sure. But nothing we know about polar bears and their habitats suggests that could result at levels that would benefit today’s populations.
So, we have no reason to believe polar bears will persist if sea ice is allowed to continue to decline. And it is certain that the world will continue to warm and ice continue to decline as long as GHG levels in the atmosphere rise. This is determined by the laws of physics, and is unavoidable. I am not aware that even the most ardent climate change deniers deny this. Rather they simply ignore it. For an elegant discussion of this fact, I suggest reading the article by Raymond PierreHumbert, in the Jan 2011 edition of the journal Physics Today.
This does not mean that the earth will warm in a smooth straight line just as it doesn’t mean that every year will see less sea ice than the previous. The natural chaos in the climate system will continue and we will continue to have some periods that are “relatively” warmer and cooler than others. The difference from our historical context, is that these natural fluctuations will be occurring over a higher and rising baseline. Climate change deniers continually emphasize the natural variation while distracting us from the rising baseline. The most recent projections (Mora et al. 10 Oct 2013 issue of Nature), however, suggest that that rising baseline (the mean climate) will be continuously outside the bounds of historical variability by the middle of this century. By then, we will have lost many of the world’s polar bears. But if we have done nothing about climate warming by then, polar bears will be the least of our concerns.
Finally, I am not sure I am understanding this, but it appears that Les Johnson has accused me of plagiarism. As I am not familiar with Steven Schneider or Monika Kopacz-or their writings, I have no way to address this statement. The words in this piece are mine.
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Comment left January 24, at about 7:30 am.
Dr. Susan Crockford, Zoologist (University of Victoria and http://www.polarbearscience.com)
Dr. Amstrup, you say you did not provide the photos for this piece. How supremely odd!
You, the polar bear biologist with decades of field experience and the employee of an organization that routinely posts pictures of polar bears, left it up to the people that run this forum to provide suitable photos to accompany an article you wrote – about polar bears?
You mean you had not a single photo, out of all the encounters with skinny and starving bears you claim to have seen lately, that would have made a suitably scary/cute accompaniment to your essay?
You have also set up quite a few straw man arguments in your reply to Mr. Benton and Mr. Matthews.
1. You continue to focus on September sea ice declines: while the September declines are the most dramatic, ice declines in the months when polar bears do most of their feeding (March to June) has been minimal.
What happens in September is largely irrelevant for polar bears (see also point 3 below).
Regardless of the “trend” for September ice, sea ice for March to June has been within 2 standard deviations of the 1981-2010 average.
I’ll remind you and others what this means (according to NSIDC itself), because it is significant:
“Measurements that fall far outside of the two standard deviation range or consistently fall outside that range suggest that something unusual is occurring that can’t be explained by normal processes.”
In other words, it isn’t “abnormal” until it is outside the two standard deviation range – which means its within natural variation.
See this graph for yourselves: http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Funny that despite the cries of “starving bears,” all of the photos of bears taken in the fall that we’ve been seeing over the last few years have been nice fat bears.
Where are all the starving bears? They are not starving, because there has been plenty of ice from March to at least mid-June for them to hunt for the young seals that are so important to their survival.
2. You vigorously attack anyone with the temerity to suggest that the estimate for polar bears in 1970 was “around 5,000 animals.”
This is another strawman – it distracts readers from the undisputable fact that polar bears are a conservation success story. Polar bear numbers have increased substantially since protective measures were put in place.
Every other marine mammal species that was slaughtered as polar bears were in the late 1800s and early 1900s, including sea otters, recovered to a spectacular degree. Why imply that polar bears are different?
Compare the polar bear situation to the sea otter one: does anyone really believe that someone counted the few remaining sea otters back in the early 1900s before they were declared nearly extinct?
Yet no one attacks the biologists who suggest the sea otter population declined to “about 2,000 animals.” It’s a broad, ballpark estimate based more on known numbers “removed” (slaughtered) and reduced sightings than actual surveys.
The exact numbers are not important, they never have been.
The estimate of “about 5,000 bears” came out of the very real concern in the 1960s that polar bears would go extinct if protective measures were not put in place. They were protected and have rebounded spectacularly, by anyone’s measure. Why rail against that fact?
3. Later, you say “Polar bears stuck on land in Hudson Bay in summer lose nearly 2 pounds of body weight for every day they are on land. Would Mr. Matthews suggest they are dieting intentionally?”
Another straw man argument, as you go on to argue that somehow Mr. Matthews suggested that polar bears could simply live on land like grizzly bears – which he certainly did not do (nor did Mr. Benton).
Polar bears in many regions of the Arctic are “stuck on land” at the end of the summer and go through a period of fasting of varying lengths of time: this is entirely normal for polar bears, not something new.
Polar bears lose “2 pounds a day” because they are using the excess fat they put on in the spring and early summer – they do not need to eat while on land.
Putting on hundreds of pounds of fat in the spring to last through periods of food scarcity later in the year (whether it comes at the end of summer or over the winter) is the evolutionary adaptation that has allowed polar bears to live successfully in the Arctic.
4. Your “projections” are nothing more than a sciency-sounding crystal ball. But the ball has already broken.
The sea ice has not behaved as your colleagues predicted – September ice has declined dramatically, yet there has been no statistically significant rise in temperature for at least 16 years, while CO2 continues to increase (even the IPCC admits this).
There is simply not a demonstrable cause and effect relationship between global temperatures, atmospheric carbon dioxide and Arctic sea ice coverage for more than half of the last 30 years that constitutes the data your polar bear models use.
Both historically and geologically, sea ice coverage has been highly variable – yet polar bears have survived.
Genetic research suggests polar bears survived the Eemian warm period (115,000-130,000 years ago) – which had significantly less ice in winter than your models predict – without the population declining to anything like “near extinction” levels.
5. Your assumption seems to be that any slight, short-term decline in polar bear numbers is not only unnatural but potentially catastrophic, which is spectacularly naïve for a wildlife biologist.
All animal populations fluctuate over the short term, sometimes quite spectacularly, yet they recover.
You simply do not have enough detailed information yet to understand what the natural fluctuations in polar bear numbers might be in response to naturally changing sea ice conditions over climate-relevant periods of time – even for Western Hudson Bay, where you have the most data.
On top of that, many populations that were in a “population growth phase” as they rebounded from over-hunting in the mid-1900s have only recently been settling into a “population maintenance” phase – that’s what populations do.
Your polar bear biologist colleagues have admitted in their peer-reviewed papers that they cannot distinguish between a slowdown in population growth and a decline due to reduced sea-ice (e.g. Davis Strait, Barents Sea).
Yet you are adamant you have proof polar bears are being harmed by reduced sea ice and are certain it will get much, much worse. That’s fearmongering for donations, not science.
