# Are the Polar bears actually diminishing? **URL:** \ **Category:** Great Debates\ **Created:** [January 6, 2009, 8:56pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132 "2009-01-06T20:56:41Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 7, 2009, 8:27pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/21 "2009-01-07T20:27:13Z")
Emphasis in original Taylor is not a geologist, nor an ice specialist. He is a polar bear biologist who lives up there in the Arctic. He writes: > [@](#): > > Last stand of our wild polar bears > > Dr. Mitchell Taylor > Polar Bear Biologist, > Department of the Environment, > Government of Nunavut , Igloolik , Nunavut , Canada > > May 1, 2006 > Tim Flannery is one of Australia 's best-known scientists and authors. That doesn’t mean what he says is correct or accurate. That was clearly demonstrated when he recently ventured into the subject of climate change and polar bears. Climate change is threatening to drive polar bears into extinction within 25 years, according to Flannery. That is a startling conclusion and certainly is a surprising revelation to the polar bear researchers who work here and to the people who live here. We really had no idea. > > The evidence for climate change effects on polar bears described by Flannery is incorrect. He says polar bears typically gave birth to triplets, but now they usually have just one cub. That is wrong. > > All research and traditional knowledge shows that triplets, though they do occur, are very infrequent and are by no means typical. Polar bears generally have two cubs — sometimes three and sometimes one. He says the bears’ weaning time has risen to 18 months from 12. That is wrong. The weaning period has not changed. Polar bears worldwide have a three-year reproduction cycle, except for one part of Hudson Bay for a period in the mid-1980s when the cycle was shorter. > > \*\*One polar bear population (western Hudson Bay ) has declined since the 1980s and the reproductive success of females in that area seems to have decreased. We are not certain why, but it appears that ecological conditions in the mid-1980s were exceptionally good. > > Climate change is having an effect on the west Hudson population of polar bears, but really, there is no need to panic. Of the 13 populations of polar bears in Canada , 11 are stable or increasing in number. They are not going extinct, or even appear to be affected at present.\*\* > > It is noteworthy that the neighbouring population of southern Hudson Bay does not appear to have declined, and\*\* another southern population ( Davis Strait ) may actually be over-abundant.\*\* > > I understand that people who do not live in the north generally have difficulty grasping the concept of too many polar bears in an area. People who live here have a pretty good grasp of what that is like to have too many polar bears around. > > This complexity is why so many people find the truth less entertaining than a good story. It is entirely appropriate to be concerned about climate change, but it is just silly to predict the demise of polar bears in 25 years based on media-assisted hysteria. > > Dr. Mitchell Taylor To date I have not seen anyone who has seriously studied polar bear population statistics claim that the polar bears are currently in danger. All of the hoorah has come from that favorite of climate scientists … computer models of the predicted demise of the polar bears. Like the climate, however, polar bears have refused to conform to the models. The main danger to polar bears, as to most animals on the planet, is human hunting. w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 7, 2009, 8:38pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/22 "2009-01-07T20:38:55Z")
There is an excellent overview of the question [here.](http://assets.panda.org/downloads/statusofthepolarbear_14thworkingmtg_iucn_pbsg.pdf) It is from the IUCN/SSN Polar Bear Specialist Group. Of the 19 sub-populations of polar bears, the breakdown is as follows: Data deficient: 7 sub-populations, 59% of total population Declining: 5 sub-populations, 5% of total population Increasing: 2 sub-populations, 10% of total population Stable: 5 sub-populations, 27% of total population Note that, despite all of the claims of “they’re going extinct!! the sky is falling!!”, we have no data that would lead to that conclusion. In fact, for almost 2/3 of the bears we do not have sufficient data to say if their numbers are going up or down. Of the ones we do know about, roughly two thirds of that population are stable, a quarter are increasing, and a tenth are decreasing. So whatever your conclusions from that might be, we’d have to say: 1. Regarding the question in the OP, we have no evidence that the populations are diminishing. 2. Twice as many bears are in increasing subpopulations compared with decreasing subpopulations. 3. Mostly, as in many questions involving climate, we are short of data to draw a firm conclusion. w. ---
**Author:** ![ivan\_astikov](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@ivan\_astikov](https://boards.straightdope.com/u/ivan_astikov)\ **Post date:** [January 7, 2009, 11:17pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/23 "2009-01-07T23:17:25Z")
> [@Hamlet](#): > > Well, if he were talking about the population of Fozzy Bears, I’d consider him an expert. - drum roll from Animal \* ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 8, 2009, 12:07am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/24 "2009-01-08T00:07:15Z")
> [@brazil84](#): > > If you look at Part II, Professor Carter points out that there have been rates of change of temperature far higher in the past than now. On the basis of what does he make this claim? There is evidence that there have been rapid regional changes in climate but the rate of change in going from cold to warm between glacial and interglacial periods is, on average, something like 0.1 C per century. (The rate going the other way tends to be even slower.) ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 8, 2009, 12:20am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/25 "2009-01-08T00:20:09Z")
> [@jshore](#): > > On the basis of what does he make this claim? There is evidence that there have been rapid regional changes in climate but the rate of change in going from cold to warm between glacial and interglacial periods is, on average, something like 0.1 C per century. (The rate going the other way tends to be even slower.) Say what? I’ll see your tenth of a degree per century during the last glacial transition and raise you three orders of magnitude … emphasis mine … > [@](#): > > The Younger Dryas is one of the most well-known examples of abrupt change. About 14,500 years ago, the Earth’s climate began to shift from a cold glacial world to a warmer interglacial state. Partway through this transition, temperatures in the Northern Hemisphere suddenly returned to near-glacial conditions (Figure 6). This near-glacial period is called the Younger Dryas, named after a flower (Dryas octopetala) that grows in cold conditions and became common in Europe during this time. The end of the Younger Dryas, about 11,500 years ago, was particularly abrupt. In Greenland, **temperatures rose 10° C (18° F) in a decade** (Figure 6; Cuffey and Clow, 1997). SOURCE: [NOAA World Data Centre for Paleoclimatology](http://www.ncdc.noaa.gov/paleo/abrupt/data4.html) ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [January 8, 2009, 2:15am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/26 "2009-01-08T02:15:42Z")
> [@jshore](#): > > On the basis of what does he make this claim? There is evidence that there have been rapid regional changes in climate but the rate of change in going from cold to warm between glacial and interglacial periods is, on average, something like 0.1 C per century. (The rate going the other way tends to be even slower.) **Intention** seems to have responded to this pretty well, but I will point out that polar bears live in a particular region. Is there any reason to believe that the arctic region has NOT undergone any “rapid” changes in climate over the last couple hundred thousand years? ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 8, 2009, 2:15am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/27 "2009-01-08T02:15:46Z")
In addition to the Younger Dryas, the Vostok ice cores contain information on this as well. There are some 3,155 data points in the record. Of these 3,154 intervals, about 10% show a rate of rise greater than 0.6°/century, 4% show a rise of more than 1°/century, and 3% show a rise of greater than 1.5°/century. So yes, I think we can say that the earth has warmed faster in the past. Not sure what this has to do with polar bears, though … whether polar bears can survive warmer conditions is a different question. Since the [Greenland ice cores](http://www.gfy.ku.dk/~www-glac/data/ddjtemp.txt) show that the Arctic has cooled on the order of a 2.5 degrees in the last five thousand years, however, it seems likely that they can survive at least that much of a temperature rise … In addition, during the Holocene (the current interglacial period), a [couple](http://adsabs.harvard.edu/abs/1993Geo....21..227G) [studies](http://www.ngu.no/en-gb/Aktuelt/2008/Less-ice-in-the-Arctic-Ocean-6000-7000-years-ago/) show that there have been warmer periods (around 5,000+ years ago) when the North Pole has likely been ice free year round … and the polar bears are still here. So, I have no concern at all that the Polar Bears will be exterminated by temperature change. They are not currently diminishing as far as we can tell, and they have survived far warmer periods in the past. The Vostok cores show that the temperature peak during the last interglacial (125000 years ago, when the polar bears were already around) was about 3° warmer than at present, and they survived that nicely, thank you very much. w. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 8, 2009, 2:31am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/28 "2009-01-08T02:31:37Z")
> [@brazil84](#): > > **Intention** seems to have responded to this pretty well, but I will point out that polar bears live in a particular region. Is there any reason to believe that the arctic region has NOT undergone any “rapid” changes in climate over the last couple hundred thousand years? Well, there are a couple of points here: (1) I am not sure what the evidence is for whether the entire arctic region underwent these rapid changes in climate…although **intention** ’s reference does seem to suggest that it is believed to represent a cooling (not clear how much) hemisphere-wide. (2) For the polar bears, the issue is the direction of the change, the rapidity of the change, and what the final value is. I.e., if the final temperature rise is high enough that it supports an ice-free arctic in summer, that is a different story than if it is not. > [@intention](#): > > So yes, I think we can say that the earth has warmed faster in the past. Not sure what this has to do with polar bears, though … whether polar bears can survive warmer conditions is a different question. Since the Greenland ice cores show that the Arctic has cooled on the order of a 2.5 degrees in the last five thousand years, however, it seems likely that they can survive at least that much of a temperature rise … Well, as I noted, that is neglecting other stresses on the polar bears. Also, while it may have been 2.5 deg warmer in Greenland (than some reference value that is presumably more akin to the pre-industrial temperature than the current one), warming is magnified in the arctic relative to the rest of the global…So, if global temperatures go up 2 or 3 deg, then the arctic is expected to warm more than that (about double that, I believe). > [@](#): > > The Vostok cores show that the temperature peak during the last interglacial (125000 years ago, when the polar bears were already around) was about 3° warmer than at present, and they survived that nicely, thank you very much. Well, actually, the genetic evidence does suggest that at least some polar bears survived…but it has little to say about what effect it had on the species. And, as that Wikipedia article noted, the oldest fossil found is less than 100,000 years old. I would need someone who understands these things better than me to comment on the significance in the difference between the genetic evidence regarding when they diverged from brown bears and the fossil evidence…i.e., which is more reliable and what it might say about the bear’s prevalence more than 100,000 years ago. And, the experts in the field don’t generally seem to be as optimistic as you are regarding the dangers that the polar bears face. ---
**Author:** ![spike404](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@spike404](https://boards.straightdope.com/u/spike404)\ **Post date:** [January 8, 2009, 2:33am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/29 "2009-01-08T02:33:43Z")
“…10% show a rate of rise greater than 0.6°/century, 4% show a rise of more than 1°/century, and 3% show a rise of greater than 1.5°/century…” Having worked in petrochemical labs for ~40 years, I question the ±0.1C accuracy of any temperature measurement in a \*\*controlled \*\* environment, much less looking at bore hole specimens. Pyrometers have to have each individual lead calibrated, liquid thermometers have to have immersion levels determined, atmospheric pressure has to be measured, etc… Accuracy of 0.2 is extremely difficult in the best of circumstances. Just because a read-out goes to the first, second, or third decimal place, does not make it accurate. An average is only as accurate, as its least accurate factor. ---
**Author:** ![spike404](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@spike404](https://boards.straightdope.com/u/spike404)\ **Post date:** [January 8, 2009, 3:21am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/30 "2009-01-08T03:21:27Z")
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**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 8, 2009, 9:13am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/31 "2009-01-08T09:13:57Z")
> [@spike404](#): > > “..10% show a rate of rise greater than 0.6°/century, 4% show a rise of more than 1°/century, and 3% show a rise of greater than 1.5°/century…” > > Having worked in petrochemical labs for ~40 years, I question the ±0.1C accuracy of any temperature measurement in a \*\*controlled > \*\* environment, much less looking at bore hole specimens. > > Pyrometers have to have each individual lead calibrated, liquid thermometers have to have immersion levels determined, atmospheric pressure has to be measured, etc… > > Accuracy of 0.2 is extremely difficult in the best of circumstances. Just because a read-out goes to the first, second, or third decimal place, does not make it accurate. An average is only as accurate, as its least accurate factor. An interesting point, **spike404**. Sure, why not. Round them to the nearest half a degree if you like. However, remember that unlike your example, we are not looking for absolute accuracy. We are looking for relative accuracy. The requirement for absolute accuracy is absence of errors. To remove the errors, we need to know their size. The requirement for relative accuracy, on the other hand, is stability of errors. The latter, while not trivial, is much easier to achieve. w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 8, 2009, 10:16am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/32 "2009-01-08T10:16:11Z")
jshore, as always, my pleasure. > [@jshore](#): > > Well, there are a couple of points here: > > (1) I am not sure what the evidence is for whether the entire arctic region underwent these rapid changes in climate…although **intention** ’s reference does seem to suggest that it is believed to represent a cooling (not clear how much) hemisphere-wide. > > (2) For the polar bears, the issue is the direction of the change, the rapidity of the change, and what the final value is. I.e., if the final temperature rise is high enough that it supports an ice-free arctic in summer, that is a different story than if it is not. I’m not sure what the point about the changes being global or local is. Polar bears live locally, right there on Greenland and on around the arctic. The Arctic is about 4% of the earths surface. Whether the warming was just in the Arctic or whether it was global doesn’t seem to make much difference. I also don’t understand why the rate of the change would matter to the polar bears. What’s the difference if it’s half a degree per century or a degree and a half? Finally, the polar bears have lived through periods when the North Pole and Arctic Ocean was ice free. Why would reaching that point again be different than the last time? [QUOTE=jshore] Well, as I noted, that is neglecting other stresses on the polar bears. Also, while it may have been 2.5 deg warmer in Greenland (than some reference value that is presumably more akin to the pre-industrial temperature than the current one), warming is magnified in the arctic relative to the rest of the global…So, if global temperatures go up 2 or 3 deg, then the arctic is expected to warm more than that (about double that, I believe). [/QUOTE] Possible but doubtful. [QUOTE=jshore] Well, actually, the genetic evidence does suggest that at least some polar bears survived…but it has little to say about what effect it had on the species. [/QUOTE] I don’t understand this at all. What effect are you talking about? The species is thriving. Do you have some evidence of a population bottleneck? [QUOTE=jshore] And, as that Wikipedia article noted, the oldest fossil found is less than 100,000 years old. I would need someone who understands these things better than me to comment on the significance in the difference between the genetic evidence regarding when they diverged from brown bears and the fossil evidence…i.e., which is more reliable and what it might say about the bear’s prevalence more than 100,000 years ago. [/QUOTE] I’ve looked at this question a while ago. Most experts give a figure between 200,000 and 250,000 years ago for the start of the species. [QUOTE=jshore] And, the experts in the field don’t generally seem to be as optimistic as you are regarding the dangers that the polar bears face. [/QUOTE] Doesn’t surprise me. It’s a computer projection that has them worried. Do you really think we understand polar bear survival to model it on a computer? Well, they do. I’m continually stumped by the blind belief in computer models that has pervaded some parts of modern science. Yes, we know enough about some things to model them quite well. No, we don’t know enough about polar bears to predict what effect a 1° temperature rise will have on them, no matter what the modelers may claim. The problem is we have little data, few observations, inadequate censuses, and small practical experience with the critters. How on this amazing earth you plan to model that I haven’t a clue, even after reading a bunch about the program used. It’s a population biology program, where you put in a whole host of variables and assumptions and it tells you what the chances are of extinction in the next hundred years. Riiiiight … the numbers coming out are only as good as the numbers going in, and we don’t know enough about polar bears to be able to give anything but guesses for those numbers. We also don’t know the effect of a 1% temperature rise on the local ecosystem. Finally, animals are supremely adaptable, particularly a smart top predator. They have to be to survive. Funny, there wasn’t a place to enter “adapability” in the computer program that I could find … In any case, I’ve given you Dr. Mitchell Taylor’s opinion, and he’s one of the more eminent people in the field. He lives up there and studies the bears. It is also the opinion of the natives of Nunavut. Despite all the doom and gloom coming from ivory towers, they locals say there’s more polar bears around than average. Even the IUCN says that, despite the recent warming, more bears are in expanding populations than shrinking. If the warming is harming them, there’s no evidence of it. Hey, computer models not matching observations … remind you of anything? So no, I’m not worried. I leave that to fools who believe that computers can forecast the effect of a small temperature rise on polar bear dynamics. The people in the field aren’t worried … I’ll take their word. I’d say definitely keep an eye on the polar bears, keep studying them … but even the most rabid AGW proponents say they’re not in any trouble. The worst they can say is “oh my gosh, you can be sure that doom is just around the corner for the poor polar bears, and if you don’t believe me, well, just ask my computer” … w. ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 8, 2009, 11:26am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/33 "2009-01-08T11:26:50Z")
Another thought. Polar bear are a species like say elk, for which hunting licenses are issued. And just as for elk, the number one killer of polar bears is hunting. Hunting selectively removes healthy adult bears (as opposed to a cub dying). The management of the polar bear populations is done by deciding how many permits are issued. For example, in 2005 for Western Hudson Bay, at Dr. Taylor’s recommendation (he’s the government biologist), the Nunavut Government cut the polar bear quota from 56 polar bears (plus what the locals kill) to 38 polar bears. In other areas the quotas were kept steady. So when Dr. Taylor says Canadian bears overall are not in need of any special protection now, if anyone should know, he should. I’ll take his word over that of a computer. Greenland is the wild card. In some recent years they have taken as many as 200 bears. Yes, some sub-populations are shrinking … My point is that hunting, not climate, is what is regulating the polar bear population. We should do with polar bears what we do with all other managed populations like deer and elk and pronghorn and pheasant and trout and a host of others. Continue to manage them, set quotas by sub-populations, adjust the quotas down or up as circumstances dictate, get better at counting them, and get concerned when we actually see something indicating trouble. Me, I don’t think they should be hunted by anyone but the locals … but hey, that’s just me. w. ---
**Author:** ![ch4rl3s](https://avatars.discourse-cdn.com/v4/letter/c/c4cdca/32.png) [@ch4rl3s](https://boards.straightdope.com/u/ch4rl3s)\ **Post date:** [January 8, 2009, 11:35am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/34 "2009-01-08T11:35:44Z")
[QUOTE=intention] …Note that, despite all of the claims of “they’re going extinct!! the sky is falling!!”, we have no data that would lead to that conclusion. In fact, for almost 2/3 of the bears we do not have sufficient data to say if their numbers are going up or down. Of the ones we do know about, roughly two thirds of that population are stable, a quarter are increasing, and a tenth are decreasing… w. [/QUOTE] Want to know what I found really funny about this thread? Most people seem to be accepting this position, (that we don’t know about most, but of the ones we do, more are increasing.) But when I reached the bottom of the thread, there was an ad to “Stop Global Warming,” showing polar bears. Man did I laugh. edit: (awww, the ad has changed now.) ---
**Author:** ![brazil84](https://avatars.discourse-cdn.com/v4/letter/b/8491ac/32.png) [@brazil84](https://boards.straightdope.com/u/brazil84)\ **Post date:** [January 8, 2009, 12:06pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/35 "2009-01-08T12:06:41Z")
> [@jshore](#): > > Well, there are a couple of points here: > > (1) I am not sure what the evidence is for whether the entire arctic region underwent these rapid changes in climate… I’m not sure either, but it seems to me the burden is on you at this point to come up with something besides speculation. Anyway, along the lines of what **intention** says, if polar bears are really in danger, the obvious thing to do is to stop hunting them. ---
**Author:** ![spike404](https://avatars.discourse-cdn.com/v4/letter/s/aeb1de/32.png) [@spike404](https://boards.straightdope.com/u/spike404)\ **Post date:** [January 8, 2009, 3:13pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/36 "2009-01-08T15:13:49Z")
“…remember that unlike your example, we are not looking for absolute accuracy. We are looking for relative accuracy…” The problem is that if one states a definite change of 0.4, one is stating that the accuracy is ± 0.1, or 0.35 to 0.44. I have no idea what “relative” accuracy means. ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 8, 2009, 5:21pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/37 "2009-01-08T17:21:44Z")
**intention** , thanks for your response. > [@intention](#): > > I’m not sure what the point about the changes being global or local is. Polar bears live locally, right there on Greenland and on around the arctic. The Arctic is about 4% of the earths surface. Whether the warming was just in the Arctic or whether it was global doesn’t seem to make much difference. My point was that it was not clear to me that the changes in temperature occurred arctic-wide. The arctic seems to have some fairly dramatic swings in temperature where one part becomes warmer and another colder. Perhaps in the Y-D event, the entire arctic swung in unison but I wasn’t sure if this is believed to be the case or not. > [@](#): > > I also don’t understand why the rate of the change would matter to the polar bears. What’s the difference if it’s half a degree per century or a degree and a half? With issues like rates of migration and such, I think the speed of the change could impact how animals can adapt. > [@](#): > > Finally, the polar bears have lived through periods when the North Pole and Arctic Ocean was ice free. Why would reaching that point again be different than the last time? Your claim that this is the case seems to be based on two studies that you provided links to (or about) in post #27. Of these, one study is quite old (1993) and the other, according to the article that you linked to that discusses it, leads to the conclusion that the arctic had less ice and **may** have been ice-free. By contrast, other papers in the literature have quite different conclusions. For example, [this](http://www.uri.edu/artsci/com/Logan/teaching/html/HPR319_fall_2007/pdf/Overpeck_etal_EOS2005.pdf) paper says: > [@](#): > > At the present rate of change, a summer ice-free Arctic Ocean within a century is a real possibility, a state not witnessed for at least a million years. > … > > Despite 30 years of warming and ice loss, the Arctic cryosphere is still within the envelope of glacial-interglacial cycles that have characterized the past 800,000 years. However, although the Arctic is still not as warm as it was during the Eemian interglacial 125,000 years ago [e.g., Andersen et al., 2004], the present rate of sea ice loss will likely push the system out of this natural envelope within a century. Climate models corroborate this projection with depictions of sea-ice-free summers within the same time frame [Arctic Climate Impact Assessment, 2005]. There is no paleoclimatic evidence for a seasonally ice free Arctic during the last 800 millennia. (It is worth noting that since this study was published, I believe other studies have argued that we are likely to reach an ice-free state much sooner than a century from now.) > [@intention](#): > > I don’t understand this at all. What effect are you talking about? The species is thriving. Do you have some evidence of a population bottleneck? I am not talking about now. I am talking about what happened during the last interglacial. And, I don’t really have evidence one way or the other although I am curious about the statement that we don’t have any fossil evidence for polar bears going back before that interglacial even though the genetic evidence suggests the divergence from brown bears occurred before that. > [@](#): > > Doesn’t surprise me. It’s a computer projection that has them worried. Do you really think we understand polar bear survival to model it on a computer? Well, they do. I’m continually stumped by the blind belief in computer models that has pervaded some parts of modern science. Yes, we know enough about some things to model them quite well. No, we don’t know enough about polar bears to predict what effect a 1° temperature rise will have on them, no matter what the modelers may claim. In some sense, I don’t disagree with you. I don’t think we do know enough to know for sure what will happen. However, we know enough to be very concerned. And, strangely enough, it seems that you seem to believe that you know enough not to be worried…i.e., you seem to have greater certainty than those who you are arguing against. They may be relying to some degree on computer models that are imperfect but I don’t even think you are relying on that. > [@](#): > > In any case, I’ve given you Dr. Mitchell Taylor’s opinion, and he’s one of the more eminent people in the field. He lives up there and studies the bears. > > It is also the opinion of the natives of Nunavut. Despite all the doom and gloom coming from ivory towers, they locals say there’s more polar bears around than average. This seems to be a minority opinion. And, might you also think that the opinion of the natives could be influenced by a factor that you go on to discuss…the fact that they want to be able to hunt polar bears? > [@](#): > > So no, I’m not worried. I leave that to fools who believe that computers can forecast the effect of a small temperature rise on polar bear dynamics. The people in the field aren’t worried … I’ll take their word. I’d say definitely keep an eye on the polar bears, keep studying them Actually, all that you have shown is that there exists one scientist and some natives “in the field” who are not worried. I am not sure how you get from this to your statement that “the people in the field aren’t worried.” > [@](#): > > We should do with polar bears what we do with all other managed populations like deer and elk and pronghorn and pheasant and trout and a host of others. Continue to manage them, set quotas by sub-populations, adjust the quotas down or up as circumstances dictate, get better at counting them, and get concerned when we actually see something indicating trouble. These things all need to be done but if we destroy their habitat in a way that they are not able to adapt to (rapidly enough), it won’t do much good in the end. ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [January 8, 2009, 6:12pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/38 "2009-01-08T18:12:55Z")
> [@jshore](#): > > He does this primarily by pointing to a considerably warmer interglacial period (at least for Greenland) that occurred some 300,000 years ago or so without bothering to discover that the current polar bear [hasn’t actually been around that long](http://en.wikipedia.org/wiki/Polar_bear): “According to both fossil and DNA evidence, the polar bear diverged from the brown bear, Ursus arctos, roughly 200,000 years ago. The oldest known polar bear fossil is less than 100,000 years old.” Hence, it appears that the polar bears have, at most, survived only one previous interglacial period (the one about 100,000 years ago). However, the warming expected over the next century would differ from that one in that the speed of the warming would be much more rapid plus at the same time there are additional stresses on the bears due to other human factors (e.g., persistent organic pollutants, encroachment on their habitat, and human competition with their food sources). Also, depending on our emissions and the climate sensitivity, the temperature in the next century is possibly, if not likely, to surpass the temperature in this previous interglacial. This is presumably why, as the Wikipedia article I linked to notes: Note the > **[Medieval Warm Period](https://en.wikipedia.org/wiki/Medieval_Warm_Period)** > > The Medieval Warm Period (MWP), also known as the Medieval Climate Optimum or the Medieval Climatic Anomaly, was a time of warm climate in the North Atlantic region that lasted from about 950 CE to about 1250 CE. Climate proxy records show peak warmth occurred at different times for different regions, which indicate that the MWP was not a globally uniform event. Some refer to the MWP as the Medieval Climatic Anomaly to emphasize that climatic effects other than temperature were also importa Th... which was only 700-100 years ago. The MWP was apparently warmer than it is now, in that area. And as **intention** mentioned there was the Younger Dryas and other periods. There is little doubt that the Polar bear may be in trouble if conditions get as bad as some projections show. But it does not seem as if the Polar bears are in any danger _right now._ ---
**Author:** ![jshore](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@jshore](https://boards.straightdope.com/u/jshore)\ **Post date:** [January 8, 2009, 6:22pm UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/39 "2009-01-08T18:22:48Z")
By the way, [here](http://www.epa.gov/climatechange/effects/eco_animals.html) is an EPA page that mentions the polar bear and has some other good links. They say: > [@](#): > > For example, polar bears are dependent on sea ice to hunt seals and to move from one area to another. Polar bears are unlikely to survive as a species if there is an almost complete loss of summer sea-ice cover, which is projected to occur before the end of this century by some climate models. The seals that polar bears hunt are also unlikely to be able to adapt to an absence of summer sea ice, because they give birth to and nurse their pups on the ice and use it as a place for resting. I assume there may be a more extensive discussion available associated with the [Interior Department’s decision to list the polar bear as a threatened species](http://www.interior.gov/issues/polar_bears.html). Here is what they had to say in regards to the computer models projections of ice cover (bolding added): > [@](#): > > In developing the nine studies it delivered to the Fish and Wildlife Service, the USGS relied upon 10 peer-reviewed climate models, all of which project a decline in Arctic sea ice in the future. In particular, the models project declines in September sea ice of more than 30 percent by the middle of the 21st century. Four of the 10 models project declines in September sea ice in excess of 80 percent by the mid -21st century. Seven of the 10 models show a 97 percent loss in September sea ice by the end of the 21st century. > > **Based on actual observations of trends in sea ice over the past three decades, these models may actually understate the extent and change rate of projected sea ice loss.** ---
**Author:** ![intention](https://avatars.discourse-cdn.com/v4/letter/i/e95f7d/32.png) [@intention](https://boards.straightdope.com/u/intention)\ **Post date:** [January 9, 2009, 5:40am UTC](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132/40 "2009-01-09T05:40:21Z")
jshore, many thanks for your additions to the discussion. The computer models of the ice are no better than the models of the temperature. The PDO (Pacific Decadal Oscillation) has been in a warm phase for three decades. The change in temperature in Alaska was a step jump of a couple degrees in temperature. It’s visible in temperature records all over the state. So it is no surprise that the ice was melting. However, the PDO has now changed to the cool phase, and the Arctic is cooling as a result. Now, some genius takes a ruler (or his whizbang you-beaut computer program) and puts it on that past trend of decrease line and goes “oh my god, the arctic will be ice-free by 2040.” But in fact, at present the earth is cooling and the ice is rebounding. Globally, we currently have more ice than we’ve ever had since satellite records began. Not one computer model has forecast that, in any way. Not even near. (I could put a ruler on increasing ice graph and say “oh my god, NY will have pack ice by 2040” … but I’m not that smart.) So just like the climate models of the earth heating up in the 20th century, the climate models of the ice are wrong already as well. The earth has not warmed this century, sea level rise is flattening out, and the ice pack is increasing … find me a computer model that predicted any of those. I note also that the danger point of no summer ice in the first quote is projected by “some” climate models to occur sometime in the next ninety two years … hardly a call for urgent action. Finally, I doubt if the climate models were “peer-reviewed” as the USGS is quoted as saying. I’ve never seen a “peer-reviewed” climate model, don’t even know how one would go about the review. It is precisely that lack of independent review of the models that I have been decrying for some time now. w. PS - “worried” scientists are a glut on the market these days. Stacks of scientists are hyping all kinds of dangers, and they’re all “worried” to a man (or woman), because … well, because few people will give money to study the lily-livered mugwort. But if you say “my model shows that in thirty to fifty years the mugwort may be wiped out by climate change”, you might get a grant. So you’ll forgive me if I yawn when the latest scientist comes in to tell me of some huge danger that will appear “sometime this century”, as in your first quote above. I give them a ticket and ask them to stand in line, there’s plenty of imagined catastrophes to go around. For example, Hansen is now saying that the continued export of Australian coal will “guarantee destruction of much of the life on the planet” … Guarantee? Say what? I should get worried because of James Hansen’s “guarantee”? I note that, unlike any guarantee I’ve ever heard of, he’s forgotten to tell us what will happen when he’s wrong. I mean, is it a money-back guarantee for the billions he wants us to spend? Have you noticed that as the world grows colder, as the sea level rise has declined, as the ice has increased, our boy Jim has grown shriller. Now he’s “guaranteeing” that he is right … does that sound real scientific to you? I’ve never met a scientist who did that. Have you? Pathetic. The man is a media whore, giving thousands of interviews when he is supposed to be working, and then complaining he’s being “muzzled” … I only wish. [Previous page](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132.md?page=1) [Next page](https://boards.straightdope.com/t/are-the-polar-bears-actually-diminishing/480132.md?page=3)