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Comments 108501 to 108550:
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ginckgo at 13:59 PM on 1 October 2010Newcomers, Start Here
What the "polar bears will just adapt" crowd seem to not understand about evolution, is that adaptation to a changing environment is far from guaranteed. The major mass extinctions in the past have all occurred when environmental change was too rapid and/or environmental stress was too strong. This is what we're seeing today. Plus, mass 'extinction' is perhaps a misnomer, as some events are marked by extinction rates dramatically elevated above background levels, while others are marked by dramatically reduced speciation rates. I think our double wammy of human encroachment and environmental change is causing both to occur at the same time. -
Tom Dayton at 13:21 PM on 1 October 2010Models are unreliable
A good, short, essay on the role of computer models in science is in the journal Communications of the ACM, the September 2010 issue, page 5. I can see it on line for free, but I don't know if that's because I'm an ACM member: Science Has Only Two Legs. -
archiesteel at 11:58 AM on 1 October 2010Newcomers, Start Here
@CW: that's your rebuttal? Weak. Changing light bulbs (preferabley to LEDs) and driving hybrid/electric cars is just smart, regardless of the overwhelming amount of evidence supporting AGW theory. Oil is too valuable to use as fuel. -
DSL at 11:44 AM on 1 October 2010Newcomers, Start Here
Ignoring Doug's correction, what you say is right, CW: we should go ahead and take these poor ------s out in the next 50 to 100 years with our paltry 3-7 C warming, because there's no way they could continue to evolve over the next 20,000-30,000 years as insolation slowly creeps toward max. Why stretch it out for them? Indeed, let's go ahead and make that choice for all the other species we couldn't possibly be affecting by our slight changes to the biosphere. Who needs em? What a work is man! How infinite in reason! Or was it density or greed or something like that . . . -
Doug Bostrom at 11:27 AM on 1 October 2010Newcomers, Start Here
I believe you're mixing up BP w/AD, CW. -
ClimateWatcher at 11:23 AM on 1 October 2010Newcomers, Start Here
By the way, if you can repress the memory of the HCO ( the peak just prior to the blue dot which marks the present ), and are still convinced that changing your light bulbs ( or as Nissan would sell you, driving a 'Leaf' ) will have any bearing whatsoever on the Ursus Maritimus ( polar bears ), do reflect that nature is going to irradiate the Arctic with greater summer sunshine than present for most of the next fifty thousand years:
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David Horton at 10:59 AM on 1 October 2010IPCC Reports: Science or Spin?
Yes, nicely done Graham. Worth noting too that whatever "political pressure" may be operating on the IPCC in a general sense is operating in the direction of toning down warnings, as a result of countries such as the US and Saudi Arabia being determined that nothing will be allowed to slow down the profit stream from oil. And that there will be none of this regulation nonsense getting in the way of [polluting] business as usual. Since there has to be consensus this results in only the lowest threat levels being acceptable to all. Whenever individual climate scientists are able to speak without political pressure (and this pressure operates within countries too, again the US being a prime, though not the only, example) their real views are much more gloomy than the IPCC consensus position. -
Doug Bostrom at 09:48 AM on 1 October 2010Newcomers, Start Here
CW's chart is from NOAA, Rob. They've got an interesting discussion of paleoclimate information available. It's a little long in the tooth, last updated 2006. For some fresher Arctic paleo information, see History of sea ice in the Arctic (Polyak et al, 2010) and Temperature and precipitation history of the Arctic (Miller et al, 2010)
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Rob Honeycutt at 09:25 AM on 1 October 2010Newcomers, Start Here
ClimateWatcher (#6)... BTW, where does that diagram come from? What's the source of the data? Robert Way would know far better but the numbers look a little fishy to me. And it's always a red flag if there is no source referenced. -
kdkd at 09:25 AM on 1 October 2010Newcomers, Start Here
While the comment about the bear de-evolving it's white coat is silly (it would require a change in the bear's phenotype which would take a very long time indeed to evolve) the previous comments about the Hudson Bay population are interesting. This appears to be an example of learned behaviour which is quite different from evolved behaviour (or evolved physical characteristics). So it's quite possible that the bears will learn to adapt to ice free summers where possible as they are intelligent long-lived animals. However this has absolutely nothing to do with evolution. -
Doug Bostrom at 09:22 AM on 1 October 2010NASA-GISS: July 2010-- What global warming looks like
Not to reignite the flames of controversy over whether 145 x 10^20 Joules per year of increased energy per year retained on Earth must certainly remain invisible to us but rather just to follow up on the original topic, here are are a couple of items looking back on this past summer, from NASA-GISS: 2010 — How Warm Was This Summer? How Warm Was Summer 2010? -
Doug Bostrom at 09:01 AM on 1 October 2010New temperature reconstruction vindicates ...
KR: ...long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. Also foraminifera, coccolithophores, diatoms. C in C02 ends up in hydrocarbons, carbonates. Of course we're short on enormous shallow seas these days. -
Rob Honeycutt at 08:59 AM on 1 October 2010Newcomers, Start Here
fydijkstra... What I believe you are also pointing out with your comments is that it takes many thousands of years for evolution to allow these species to adapt. They are not going to readapt to an ice free environment over the course of a few generations. It's important to protect species for obvious reasons, but I keep saying that polar bears are the canary in the coal mine. They should be a sign to us that something serious is afoot. ClimateWatcher (#6)... I would point out that what you are claiming here does not account for any further rise in temperature. By this chart you might not conclude that the HCO was warmer than today. But that placed aside, what we are looking at is a rise of another 2-3C in global average temps (more in high latitudes) in this century. As a species polar bears have very definitely never seen such conditions. -
kdkd at 08:56 AM on 1 October 2010New temperature reconstruction vindicates ...
Follow up from #85 Of course there's an easy way of assessing the significance of the difference between the trends - correlate the difference between the 1990s and the 2000s against the position in the series. This gives a correlation coefficient of -0.07, 95% confidence interval of -0.67 to +0.58. As this confidence interval intersects zero (and as I indicated previously is a very wide interval) there's clearly no significant difference between trends in the 1990s and the 2000s as measured by the annualised satellite data. For this analysis to be statistically significant the correlation would have to be (0.58 - 0.67)-1 = 0.91 which would be very difficult to achieve with this system, even if we were seeing clear evidence of runaway global warming (or cooling) over such a short time frame. -
Nick Palmer at 08:42 AM on 1 October 2010New temperature reconstruction vindicates ...
#81 johnd at 06:47 AM on 1 October, 2010 wrote: "If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions" Perhaps you might like to consider the difference between short and long term sequestration. I was referring to the digging up of (semi-)permanently sequestrated carbon. -
New temperature reconstruction vindicates ...
johnd - My point was that seasonal CO2 variations due to the growing season are very definitely not the trend - and that you cannot count on large seasonal variations to take care of a multi-decade CO2 increase. -
adelady at 08:29 AM on 1 October 2010Newcomers, Start Here
fydijkstra "So what's wrong with adaptation of the polar bear? If it does not need its white color any more, so what?" And how long did that earlier adaptation take? 50 generations, 100 generations, 1000 generations? This kind of evolution does not happen in the space of a few years or a few generations. Nobody's suggesting that we should stand in the way of natural evolution. The kind of time scale our emissions are imposing is not conducive to natural evolution. -
johnd at 08:29 AM on 1 October 2010New temperature reconstruction vindicates ...
KR at 08:09 AM, the rate at which CO2 is being moved deeper in the oceans will be tied to the rate at which the heat also absorbed at the surface is redistributed and moved deeper, and that, whilst subject to great discussion, is more reflective of shorter rather than longer term circulation. -
Albatross at 08:20 AM on 1 October 2010New temperature reconstruction vindicates ...
Matthew @80, I concur with kdkd, or rather Hansen does ;) "Contrary to a popular misconception, the rate of warming has not declined. Global temperature is rising as fast in the past decade as in the prior two decades, despite year-to-year fluctuations associated with the El Nino-La Nina cycle of tropical ocean temperature. Record high global 12-month running-mean temperature for the period with instrumental data was reached in 2010." From: Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., in press, doi:10.1029/2010RG000345. -
kdkd at 08:14 AM on 1 October 2010New temperature reconstruction vindicates ...
Matthew #80. "Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true? Nope. Firstly you can't really assess trends properly over such a short time period in isolation due to a lack of statistical power. The difference in trend is almost certainly not statistically significant even before correcting for autocorrelation. The calculation for actual statistical significance is fiddly so I'm not going to do it, but with 10 paired data points it would require quite a large difference in correlations to be significant (probably greater than r=0.6 from memory) - the observed difference in correlation is only 0.15 which is definitely not statistically significant for 10 paired observations. Looking at the satellite data for 1990-1999 and comparing it to the satellite data for 2000-2009, the mean anomaly for the 2000s is 0.25 deg C greater for the 2000s period than for the 1990s period (95% confidence interval: 0.095-0.40). -
New temperature reconstruction vindicates ...
johnd - Seasonal variation is cyclic; what goes in comes out. Actual long-term sequestration of CO2 occurs through rock weathering, subduction in ocean zones, and the formation of those hydrocarbons we're so rapidly burning. The long term trend is what's important, currently +2ppm/year, not seasonal variations. The only long term sequestration of CO2 involves plants that are not then burnt, eaten, or rotted away. That's a pretty small portion. -
Same Ordinary Fool at 07:37 AM on 1 October 2010Newcomers, Start Here
The story of polar bears coping without sea ice has already been filmed. Several years ago I saw an hour long show about a mother and cub who missed the departing sea ice. They were stuck on shore for the rest of the summer. They missed the salmon run, because they didn't know about it. They did find the berries. Mom was pretty gaunt by the end of the summer. Unlike in the Arctic, the Hudson Bay sea ice disappears completely during the summer. So entire subpopulations there are forced onto land. The good news is that the polar bears have evolved the ability to survive a summer long fast. The bad news is that in a warming world the time on shore is getting longer. Ironically, when the multi-year ice becomes even thinner, there will be some new areas that the polar bears can move into. These are areas where the ice is now too thick for the seals to maintain their breathing holes. fydijkstra @ 5:59Am.....The other evolved traits that make it the perfect maritime bear, work against it on land. Its big and slow. Its calorie requirements that are currently met by seals (an adult polar bear eats only the fat) can't be met on shore. And, most importantly, its the grizzly bears that win in fights with polar bears (if only the polar bears learned to use their nose butt...). -
johnd at 07:31 AM on 1 October 2010New temperature reconstruction vindicates ...
KR at 07:14 AM, the CO2 sequestration of the oceans and the plants and soil are divided roughly equal. The drop in CO2 levels that coincide with the seasonal growing periods in each hemisphere show that the plants and soil are a significant destination for CO2 with a capacity that is only partly utilised for a portion of each annual cycle. -
New temperature reconstruction vindicates ...
johnd - Actually, much of the anthropogenic emissions are going right into acidifying the oceans. It takes quite some time for that absorbed CO2 to move deeper. The rate required to be absorbed by the environment and not change ocean pH would be much much smaller than 50% of current emissions. -
johnd at 06:47 AM on 1 October 2010New temperature reconstruction vindicates ...
Nick Palmer at 03:20 AM, regarding your comment of digging up CO2 that took millions of years to sequester. If we look at the carbon cycle where the the natural sources and sinks exceed anthropogenic emissions by a factor of 30, and those natural sinks each year sequester approximately half of the man made emissions, then one could make a case showing that in fact man is only releasing carbon in one year that took two years to get down there. -
Matthew at 06:35 AM on 1 October 2010New temperature reconstruction vindicates ...
Kdkd 2000-2009 warmed about .15c, which is below the 1990's. Is that true? -
kdkd at 06:32 AM on 1 October 2010New temperature reconstruction vindicates ...
KL #74. We've been through the scientific argument many many times. You seem to claim that the ocean heat content data is capable of falsifying the remaining evidence for anthropogenic global warming. You do not seem to have any other 'evidence' to support this position. A large and important part of your position is the need to maintain the pretence that the existing measures of ocean heat content are accurate enough to draw strong conclusions. It has been demonstrated to you many many times that it is not. As you have no other argument to support your position, you maintain the position regardless of the evidence presented to you (like the 'flattening of temperature post 1998' claim that you cling to as well), I think that repetitive rubbish is a fair comment which summarises your argument well. -
Positive feedback means runaway warming
hadfield - Your statement "a system with positive feedback is by definition unstable" is incorrect, a system with a gain < 1 is stable, as discussed at some length here, and in better detail on the advanced version of this page. Total stable increase for a particular gain (g<1) and forcing (f) is, if you work the math: V = f / (1-g) The oft-quoted 3oC increase for a doubling of CO2 (forcing = 1oC) represents a gain of 0.666. This, incidentally, works for negative feedbacks as well - gains with an absolute value < 1.0 are always stable. Differing time constants may cause some oscillation before settling, but systems with |g| < 1.0 are always stable. Gains > 1 don't tend to exist in natural systems (as they would require infinite energy!); they're pretty common in electronics, amplifying values until you hit the limits of the power supply. -
fydijkstra at 05:59 AM on 1 October 2010Newcomers, Start Here
The polar bear evolved only 100,000 years ago from the brown bear. In fact it is still the same species: brown and white bears can mate and reproduce. The white color of the polar bear is useful in its present habitat. This white color was developed because the survival rate of white variants was higher than of dark variants. If the bear has to change its habitat, it will adapt again, and probably lose its white color. This is simply how evolution works. It's the same as when humans migrate from Africa to Europe, as they did 50,000 years ago. They lost their black skin pigments, because in Europe their skin needed more intense UV-exposure to produce vitamin D than in Africa. So what's wrong with adaptation of the polar bear? If it does not need its white color any more, so what? The bear as a species is not threatened by climate change, but by human overpopulation. -
hadfield at 05:38 AM on 1 October 2010Positive feedback means runaway warming
OK. The trouble with addressing "sceptic" claims is that they are often rather incoherent, so it can be damned hard to work out they are in the first place. If you have any examples of the claim you are addressing, that would help focus the discussion. In the absence of that, I can think of two versions of the "sceptic" claim. The first is that a system with positive feedback is by definition unstable. "Alarmists" are always pointing to positive feedbacks, some of them with short time scales like the water vapour feedback and ice-albedo feedback. But the climate is clearly not unstable so the positive feedbacks must not exist, or must be outweighed by negative feedbacks. The answer to this is that there is a large negative feedback that is fundamental to the Earth system and that is not usually identified as a feedback, namely the Planck feedback as I've discussed earlier (see also the recent article by Chris Colose on Realclimate). That feedback on its own dictates that the Earth's climate sensitivity will be fairly low. The evidence is that there are several fast positive feedbacks that act to increase the sensitivity, but nowhere near enough to make the system unstable. A second version of the claim might be that "alarmists" are saying the carbon cycle feedbacks will cause runaway warming a la Venus. The problem with this claim is that no "alarmists" are actually saying this, except Jim Hansen who has suggested it as a very remote possibility, but obviously one with huge consequences. Your discussion of the logarithmic dependence of the greenhouse effect on greenhouse gas concentrations tells us one reason why this runaway warming is not easily triggered. The fact that the Earth has not done so in the past also shows us it's hard to set off. Neither of these things indicate that it's completely impossible. To be of any help in avoiding confusion, your article needs to be clear about what claim it is addressing. At the moment it's not. Specifically, it conflates fast and slow feedbacks. -
archiesteel at 04:53 AM on 1 October 2010Newcomers, Start Here
One more thing: it's unfair to compare Arctic temps during the HCO to current global averages; we should compare modern Arctic temperatures instead. Overall, we see the rate of change is about twice the observed rate, with some regions exhibiting increases of 2 to 3C, putting the current warming in the same range as ClimateWatcher's map.
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archiesteel at 04:07 AM on 1 October 2010Newcomers, Start Here
@CW: "unfortunately, just like the bears of Yellowstone, the Polar Bears tend to BENEFIT from human settlements by raiding their garbage." How about humans? How do they benefit from increased human/bear interactions? You have to realize bears who raid garbage dumps near human settlements are also likely to be shot, which isn't very good for them either. "That aside, temperatures were much warmer during the Eemian and the HCO for thousands of years." Actually, there were no actual polar bears in the Eemian: they started to diverge from brown bears 150,000 years ago, but the real differentiation occured later, perhaps even as late as 20,000 years ago. Also, temperatures weren't "much warmer" everywhere in the HCO (according to your map). What's to say polar bear populations didn't congregate to Northern Quebec, where it was actually colder, or Greenland and the Behring strait, which were as cold as today? Overall temperatures may have been as high as 1C above the baseline, but we're already past the 0.5C mark, and likely to go above the highest estimates for the HCO before 2050. Furthermore, not everyone agrees the HCO was warmer overall. Some studies claim only a 0.2 to 0.6 increase (which means we could have passed the HCO already), while others claim there was an actual decrease in SST at the time. From the abstract of Tropical Pacific climate at the mid-Holocene and the Last Glacial Maximum simulated by a coupled ocean-atmosphere general circulation model: "Simulations for the mid-Holocene (6000 years before present: 6 ka) and the Last Glacial Maximum (LGM: 21 ka) have been performed by a global ocean-atmosphere coupled general circulation model (GCM). After the initial spin-up periods, both runs were integrated for about 200 years. For 6 ka the model shows an enhanced seasonal variation in surface temperature and a northward shift of the African and the Indian summer monsoon rain area. Overall circulation features in the tropics correspond to a strong Walker circulation state with negative sea surface temperature (SST) and precipitation anomalies in the central Pacific and positive precipitation anomalies over the Indian and Australian monsoon regions. It is noted that there is about a 0.35°C cooling of the global mean SST." (emphasis mine) "Sorry ladies," Stay classy. "this is one of the most egregious errors of the global warming campaign." First, it's not a "campaign", it's science. Second, you have yet to make successfully make the case for any of your affirmations. Careful, your bias is showing, and it's kind of ugly. -
JMurphy at 04:03 AM on 1 October 2010Newcomers, Start Here
Why are some so blase about the supposed survival of species that have survived thus far ? Maybe they know more than those actually working in this area ? It would seem they believe so. However, I refer to the experts in the field : "We have found that polar bears actually survived the interglacial warming period, which was generally warmer than the current one," Lindqvist says, "but it's possible that Svalbard might have served as a refugium for bears, providing them with a habitat where they could survive. However, climate change now may be occurring at such an accelerated pace that we do not know if polar bears will be able to keep up." Ultimately, she notes, the polar bear species may prove less adaptive. "The polar bear may be more evolutionarily constrained because it is today very specialized; morphologically, physiologically, and behaviorally well-adapted to living on the edge of the Arctic ice, subsisting on a few species of seals," she says. Ancient DNA from Rare Fossil Reveals that Polar Bears Evolved Recently and Adapted Quickly Charlotte Lindqvist, Stephan Schuster, Yazhou Sun, Sandra Talbot, Ji Qi, Aakrosh Ratan, Lynn Tomsho, Lindsay Kasson, Eve Zeyl, Jon Aars, Webb Miller, Ólafur Ingólfsson, Lutz Bachmann, and Øystein Wiigd. Complete mitochondrial genome of a Pleistocene jawbone unveils the origin of polar bear. Proceedings of the National Academy of Sciences, Mar. 1, 2010 'Rubbish !', says the so-called skeptic, I believe what I want to believe... -
Nick Palmer at 03:59 AM on 1 October 2010It hasn't warmed since 1998
@Eric (skeptic) #63 Bear in mind that increased water vapour (leading to increased clouds and precipitation) would also be in the (generally) much bigger gaps between any clouds. Some confuse water vapour (invisible and a powerful greenhouse gas) with condensed water vapour (steam) which makes up clouds. -
Nick Palmer at 03:20 AM on 1 October 2010New temperature reconstruction vindicates ...
@adelady #76 Over many hundreds of millions of years volcanoes have been releasing CO2 from non-biological subterranean sources of carbon. Without life sequestering the carbon back down underground again, CO2 would continue to build up. Life as a whole acts as a negative feedback to prevent CO2 buildup thus stabilising temperatures to its benefit. One element of life (HomoSapiensFatuus) has recently been acting as a positive feedback. As you say, we are digging up in a few decades what took millions of years to get down there. -
Paul D at 02:54 AM on 1 October 2010Newcomers, Start Here
ClimateWatcher: "The polar bears survived the millenia long Eemian and the Holocene Climatic Optimum just fine:" C'mon CW, use a few of those brain cells of yours. Assuming you were correct, how many cities, villages and human civilisations did the polar bears encounter when they migrated and survived? (5million in the Holocene versus 6billion today, 9billion in 2050). Even if today they were not endangered by global warming, every species on the planet is endangered by human growth and exploitation of resources. If you add to that, global warming, then polar bears haven't a hope in hell. -
CBDunkerson at 02:17 AM on 1 October 2010Newcomers, Start Here
ClimateWatcher, given continuation of the rate at which the Arctic has been warming the discrepancies shown on your map, even if accurate, would all be overtaken within a few decades. Also, polar bears and brown bears remain completely inter-fertile even today - though neither can survive for long in the other's primary habitat. Dentition shows that the 'modern' polar bear has been around for less than 20,000 years... long after the Eemian. Earlier 'polar bears' were much less adapted to a life on sea ice and thus able to survive warm periods on land like the brown bears they interbred with. If current polar bears were forced to survive on land their numbers would be vastly reduced and they'd be forced into brown bear territory... where they would inter-breed and quickly cease to exist as a separate evolutionary offshoot. Yes, the imposition of hunting restrictions was clearly responsible for the polar bear recovering from near extinction up to a stable population... just as the loss of sea ice is now clearly responsible for the reversal of that trend. -
archiesteel at 02:14 AM on 1 October 2010Newcomers, Start Here
Wow, I'm really sorry, I could have sworn cruzn246 had posted that comment. I guess my coffee hasn't started kicking in yet. Please disregard the last two paragraphs as they were written with cruzn246 in mind (but not the first one after the colon, that still applies). Sorry for that, CW. We disagree on some things, but you're clearly not the trolling denier type (unlike cruzn246). -
Riccardo at 02:14 AM on 1 October 2010Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
HumanityRules, the graph you show is Surface Mass Balance (SMB), just part of the story. The mass balance is reported in table 5. You can see that, altough none of the values is statistically significant, there has been a reduction from +22 for 1962-1990 to -36 (km3/yr WE) for 1998-2003. Also, the authors warn: "However, the ‘‘real’’ mass balance is probably substantially more negative because we do not take into account dynamical factors" and "our best estimates of -14 ± 55 km3 yr-1 and -36 ± 59 km3 yr-1 mass balance for 1993 – 1998 and 1998 – 2003 are much less than the -59 km3 yr-1 and -80 km3 yr-1 mass losses derived from airborne laser surveys for the same respective periods [Krabill et al., 2004], the latter including dynamical effects." -
archiesteel at 02:10 AM on 1 October 2010Newcomers, Start Here
@cruzn246: was posting that big graph really necessary? You could simply have stated the NH was warmer during the HCO. Polar bears are adaptable. They have already started moving south, and at least one polar bear/brown bear hybrid has been found in the wild. The problem is that "south" really means "closer to human settlements." Polar bears, the largest land carnivore currently in existence, are fearless, dangerous animals. How exactly is an increase in polar bear/human interactions a good thing? Incidentally, that's also the reason you mistakenly believe polar bear populations have been increasing, when actual research tends to show a decline: locals are seeing more polar bears, prompting some to say the numbers have increased, when in reality they're simply moving south to find food. You also miss the larger point. The fact that polar bears are leaving their natural habitat is a strong indication of the type of disruptive migratory patterns AGW is causing. As such, it is one more piece of evidence supporting AGW theory, the same theory you constantly (and unsuccessfully) try to undermine. See how I countered your argument without the need for a big unnecessary graph (which, BTW, climatewatcher already used on another thread)? -
Doug Bostrom at 02:07 AM on 1 October 2010Newcomers, Start Here
As you may not have intended to suggest, ClimateWatcher, the additional pressures of human interference with these animals combined with a swift loss of habitat that may or may not resemble past challenges poses a novel challenge to their population prospects. -
ClimateWatcher at 01:40 AM on 1 October 2010Newcomers, Start Here
The polar bears survived the millenia long Eemian and the Holocene Climatic Optimum just fine:
Given their dramatic population explosion since the 1970s, perhaps not shooting them quite so frequently helped them survive much more significantly than any climate variation.
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dana1981 at 01:37 AM on 1 October 2010Newcomers, Start Here
Nice summary, Anne-Marie. It's also worth noting that other species like walruses face similar impacts from declining Arctic sea ice. -
Doug Bostrom at 01:32 AM on 1 October 2010Climate Change: Past, Present, and Future
Roger, the "way of the future" relies on things such as ample access to neodymium permanent magnets, high current semiconductors and a myriad of other requirements needing a substantially globe-spanning system of materials manipulation, with means of incentives for cooperation, etc. But we're swerving well off topic here; this thread is not the right place to explore technological adaptation. I've ransacked the cornucopia of topics here and I can't find an appropriate place to take this conversation so perhaps we should leave it be. -
citizenschallenge at 00:36 AM on 1 October 2010Newcomers, Start Here
Let me share an email I received a while back on the subject: ~~~~~~~~~~~~~~~~ Your best contacts would be Drs. Eric Regehr and Karyn Rode of the FWS. If you have done so, go to the FWS Alaska Region polar bear page for information and copies of their various reports. http://alaska.fws.gov/fisheries/mmm/polarbear/pbmain.htm >>> The topic of what polar bear stock size was in the 1940’s is interesting. Obviously, there were no ‘modern’ estimates at that time. Even to this day, counting polar bears is difficult. <<< Eric is an expert on this subject. Kim Titus, Ph.D. Chief Wildlife Scientist Alaska Department of Fish and Game -
HumanityRules at 00:27 AM on 1 October 2010Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
I've got a question that maybe is at the root of why I don't understand the figure above. Here's the GRACE data from another SkSci page
Is this image saying that pre-2006 that Greenland was gaining mass (although at a slowing rate). Around 2006 it was in balance and post-2006 it was lossing mass? I'm confused about the positive and negative numbers.
Response: The confusion is my fault, apologies. I titled the graph "Change in Greenland ice mass" but I should've used the scientifically more precise "Greenland ice mass anomaly". No, Greenland wasn't gaining ice mass pre-2006 - it was losing ice mass throughout this entire period. What that graph shows is the deviation from the 2003 to 2010 average. As the ice is steadily falling, naturally ice mass levels will be above the average in the first half and below the average in the latter half. -
HumanityRules at 00:20 AM on 1 October 2010Is Greenland losing ice? (psst, the answer is yes, at an accelerating rate)
I'm curious how people are reading figure 1? The long straight line from 1960-1990 had given me the impression that there was stability in the Greenland ice sheet over this period. But when I went back to the original paper that Jiang got the data from it looked very different. The paper seems to be Hanna et al 2005 while they do present an average for that period which is what Jiang presents (and 1998-2003 which is also in Jiang's figure) they also show a full series from 1958-2003. I screen grabbed it.
( http://i52.tinypic.com/j0h091.png )
I'm not actually sure what the graph is telling me except that it looks like a huge amount of variability over that time period. And I wonder whether you have to temper any conclusions about the recent mass balance estimates in light of that?
It seems to me that buried in the idea that "Greenland is losing ice extensively and that these losses have drastically increased since the year 2000" that this is going to be part of a trend stretching into the future when in fact it could just be part of the variability seen in Hanna's data series.
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Ned at 00:12 AM on 1 October 2010New temperature reconstruction vindicates ...
Ken, that's just handwaving. A climate forcing (solar, greenhouse gases, whatever) is defined based on a departure from some base period. The Earth does not have to be in some imaginary "equilibrium" at that base period. It is perfectly straightforward to say that since 1750 (or whenever), the forcing from greenhouse gases is X and the forcing from increasing solar irradiance is Y, and X > Y or vice versa. This does not depend on anything being in "equilibrium" at 1750. I am literally unaware of anybody anywhere (other than you) who makes that claim. If there is some controversy over this point in the scientific literature that I've somehow missed, please enlighten me with a link. -
adelady at 00:02 AM on 1 October 2010New temperature reconstruction vindicates ...
Nick, I'm not so sure that that's such a bad formulation. What we dig up is the result of long ago sequestration of CO2. To me at least, it emphasises that we're releasing in a couple of dozen decades what was sequestered over many 10s of millions of years. -
Ken Lambert at 00:01 AM on 1 October 2010New temperature reconstruction vindicates ...
Ned #44 This thread is about temperature. Temperature is a measure of energy applied to or removed from the mass involved. The mass involved is the Earth system - land ice, atmosphere and ocean. Temperature does not distinguish the origin of the energy applied. The proportions of energy contributed by forcing from CO2GHG and Solar are critical to the AGW hypothesis. If there is a storage reservoir in the system (the oceans), and heat is erupting or about to erupt from this storage, then quantifying a long term Solar imbalance is as much a part of the story as 30-35 years of official AGW by CO2GHG forcing; and given the lack of evidence for short term (decadal) sequestration of heat in the oceans over the last 30-35 years might be the obvious place to look.
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