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  1. Is there any time series data available on the total global area covered by glaciers, or ice in general?

    Comment by Barton Paul Levenson — 24 May 2007 @ 4:53 AM

  2. Interesting! From Figure 2 it seems that from 1995 to 2002 all the glaciers were stable. Prior to that, there were three glaciers shrinking at the rate of 1.5 mwe per year. The others shrank at an average of 0.4 mwe per year. Since 2002 they have all been shrinking a rate of 1.5 mwe per year. That seems to imply that the faster decline rate characteristic of the southern glaciers of BC is now affecting the northern glaciers of Canada and Alaska.

    Mauri, you wrote “The question is determining which glaciers are merely out of equilibrium and can retreat to a position of equilibrium, and which are in complete disequilibrium and will melt away?” Could it be those which were declining at the rate of 0.4 mwe per year were retreating to a new position of equilibrium, but that now all are in complete disequilibrium and will melting completely away at 1.5 mwe per year?

    Comment by Alastair McDonald — 24 May 2007 @ 5:12 AM

  3. This is a good introduction to the dynamics of continental glaciers. However, the concept of mass balance is used without ever defining what it means and how it is measured. I would like to know what a value such as -0.35 m/a actually represents.

    Comment by Blair Dowden — 24 May 2007 @ 7:54 AM

  4. From what I understand, 80-90% of all world glaciers are in retreat. In the case of Greenland, where glaciers are experience an increasing number of icequakes each year, they are currently expecting that most of it will be gone in time, but there will be a small dome towards the center, assuming that global warming doesn’t get considerably worse. Then there are a few glaciers in the world (places like Greenland) where glaciers are currently in advance due to increased precipitation.

    According to Hansen, the most important time of ice loss is during the spring, not summer: ice melt at this time of the results in dark puddles which will resulting in higher summer melts and annual ice loss.

    One good place to send people for further infomation in this area is “State of the Cryosphere” at:

    State of the Cryosphere

    The intro on glaciers is at:

    SOTC: Glaciers

    Google Earth is getting into tracking the state of the cryosphere as well, I believe in cooperation with various science organizations.

    Please see:

    Google Earth Blog: Glacier Melt in Google Earth

    With Google Earth, anyone can zoom in on an area and save pictures – for websites and the like.

    For me, glaciers are important in terms of their awesome beauty. However, as they disappear, may places will be facing water shortages from the absence of runoff.

    Comment by Timothy Chase — 24 May 2007 @ 10:21 AM

  5. Sorry – you had brought up Google Earth already, and right at the end of the post where I would normally have seen it if I had been typing while at Real Climate.

    Morning commute.

    When I am on the bus, I will often try working on my posts offline in Notepad or GMail, just in case, as either a backup or what have you. In any case, the neat thing about Google Earth is that people and various organizations will be able to add their own pictures. Fish harvests giving way to unintended jellyfish catches off of Japan, algae blooms and dead zones off of the coast of Oregon, etc.. Then it will be made available to anyone with an internet connection.

    Comment by Timothy Chase — 24 May 2007 @ 10:37 AM

  6. I’m all for an endangered glacier act.

    Comment by Figen Mekik — 24 May 2007 @ 10:40 AM

  7. It appears to me that the pictures of the Lower Curtis Glacier don’t show the same region, as the ridge shown in the top center of the 1908 picture is over on the extreme right of the 2003 photo (cut off, actually). Therefore, it’s sort of hard to judge how much change there was. Maybe some recropping would be useful.

    Comment by Mitch Golden — 24 May 2007 @ 12:02 PM

  8. Very enlightening!

    Shifting the line of equilibrium reminds me of the discussion a while back about “loading the weather dice” as this relates to shifts in probabilities of certain kinds of weather. So while glaciers might indeed be getting snow, and in any given year might get a lot or little, it’s not the presence or absence of precipitation that matters as much as the overall forces influencing the balance of the accumulation of same.

    Like a gambler that wins a few and loses a few, but against whom the overall odds are in favor of long term loss. Everyone knows the odds favor the house, but we don’t usually know by how much. We also “know” that AGW is going to favor melting, but we don’t know by how much and rare “wins” in the accumulation areas of glaciers can fool us into the same kind of wishful thinking nonprofessional gamblers succumb to, that if we just keep playing we’ll get lucky.

    Comment by cat black — 24 May 2007 @ 1:05 PM

  9. Are the glaciers responding primarily to climate changes of the last 30 years, or to the post Little Ice Age conditions? In the North Cascades Rainbow, Yawning, Easton and Lower Curtis Glacier all advanced during the 1950-1975. Sholes, Columbia, Ice Worm, did not advance or retreat significantly during this period. Thus, each of these glaciers is definitively responding to the climate of the last 30 years.

    With so many glaciers worldwide how do we know that this isn’t just a regional change? The average skeptic will claim cherry picking. Also, your graphs don’t go back to 1950. What is your source?

    Comment by Leon — 24 May 2007 @ 1:27 PM

  10. How important is it really for the prognosis of the patients whether the glaciers are in equilibrium or disequilibrium with the current climate? The current climate is not going to stay – it is just a passing moment in time. Climate is warming up and will continue to do so. So isn’t the question: how many glaciers are going to survive a global warming by 2 ºC, or by 3 ºC or 4 ºC above preindustrial temperatures?

    Comment by stefan — 24 May 2007 @ 2:00 PM

  11. The 2003 picture shows it was taken in the summer. What month was the 1908 picture taken in?

    What is the seasonal change (summer versus winter) in the mass of these glaciers?

    Comment by Dave Blair — 24 May 2007 @ 2:08 PM

  12. For those interested, there are a number of images of the Lower Curtis Glacier at different times at

    Comment by Jim Crabtree — 24 May 2007 @ 7:04 PM

  13. Timothy:
    The increased frequency of icequakes in Greenland described in the Ekstrom and Tsai articles ( appear to be localized to NW Greenland glacier complexes and there is no apparent increase in other Greenland glacier complexes.

    Comment by bjc — 24 May 2007 @ 9:37 PM

  14. Who knows, Stefan?

    How many glaciers survived the last time temperatures moved above preindustrial warming?

    How many do you suppose will survive the next warming cycle, or the one after that?

    Yes, climate change is real. By the way, so is continental drift. Let’s protest to stop continental drift, or any number of other physical events.

    When we don’t understand something, it is generally a good idea to stage a protest to stop it. It sure beats figuring out what is really happening.

    Comment by Harry — 24 May 2007 @ 10:24 PM

  15. Switzerland (unsurprisingly, after all, many Swiss can see glaciers every day!) offers a nice website on glacier records from 1893:

    It has maps, top-level summaries (sortable by various fields), a next-level page per glacier with pictures/graphs, and then the actual data for each, generally starting in 1893. I really like the presentation because both graphs, summaries, and the raw data are all provided.

    Also, the following is an interesting paper on longer history of several Swiss glaciers, including the longest one, the Great Aletsch, since there are longer historical records of various kinds:

    “Glacier and lake-level variations in west-central Europe over the last 3500 years” Holzhauser, Magny, Zumbuhl

    Comment by John Mashey — 24 May 2007 @ 11:21 PM

  16. Re: #3, “Mass balance” as a measurement means the change in the average thickness of the glacier after correcting for variations in the density of the snow/ice. A value of -0.35 m/a means that averaged over its whole surface area the glacier is effectively thinning at a rate of 0.35 meters per year (“a” is for “annum”). Depending on context it may be expressed as meters water equivalent (mwe) or meters ice equivalent, but in each case the scientist making the measurement attempts to avoid the different densities of snow and ice by expressing everything in terms of the thickness that would be seen if all the material were fully compressed.

    The typical technique for measuring changes in mass balance is for scientists to stake out regions on the surface of the glacier with deeply anchored reference points and measure the change in effective thickness year to year. For example, each year a short core might be drilled to the marked reference level and the contents of that core melted to determine the water equivalent thickness. Such work is rather labor intensive since an adequate measurement really requires that the work be done at many different sites scattered across the surface of the glacier.

    Mass balance doesn’t explicitly track changes in glacier terminus or calving from glaciers that terminate in water. For this reason it is most useful for glaciers where the total glaciated volume is much larger than the terminus region.

    For the curious, here is a 50 year record of changes in mass balance based on the global compilation of Dyurgerov and Meier.

    Comment by Robert A. Rohde — 24 May 2007 @ 11:27 PM

  17. “bjc” above, citeing a paper, states a belief that icequakes in Greenland “… appear to be localized to NW Greenland glacier complexes and there is no apparent increase in other Greenland glacier complexes.”

    I read it. That’s not accurate.

    bjc, where did you get your belief that you wrote above?
    Are you quoting someone else’s opinion about what the paper says?
    Why do you believe the icequakes “appear to be localized to NW Greenland”?

    The paper describes them all around the coast. The paper describes them as increasing where the Arctic sea ice has melted, and that happened later further north.

    “… Here, we present an analysis of all 184 such events detected in Greenland between 1993 and 2005…. the events cluster into seven regions …. These regions are: Daugaard Jensen Glacier, Kangerdlugssuaq Glacier, Helheim Glacier, the southeast Greenland glaciers, the northwest Greenland glaciers, Rinks Isbrae, and Jakobshavn Isbrae.”

    Figure 3 shows the locations. You can look this up. As the Arctic sea ice has melted, the number of quakes increased.
    That has happened more recently further north (“NWG”). It happened a bit earlier further south and east, e.g. region K.

    “Other temporal trends exist but are not as compelling due to the small number of events. …. This increase in
    northerly extent correlates well with the decrease in southerly extent of arctic sea ice [Walsh and
    Chapman, 2001; Stroeve et al., 2005] and is suggestive of a common cause.”

    “… Some regions (e.g., region K) are consistent with a constant number of events per year whereas other regions (e.g., region NWG) have had an unmistakable dramatic increase during the same time period. Glacial earthquakes in region K are larger on average than in any other region, with these events comprising all of the events larger than 0.9Ã�1014 kg m. …”

    Seriously — did you get your stated belief from someone else’s opinion, or from the actual text and map?
    I’m always very curious when people make statements and give references, and I look them up and they don’t appear correct, how you got your understanding.

    Comment by Hank Roberts — 25 May 2007 @ 5:32 AM

  18. With respect to #2 if a glacier has a mass loss of -1.5 m/a year after year that is a good sign that it is seriously out of equilibrium. Yet, if it is a large glacier and a section remains reliably snowcovered the glacier could still retreat to a point of equilibrium.

    With respect to #4, plenty of posts in Realclimate focus on Greenland, but the topic here is not an ice sheet, but small alpine glaciers. An important point, is that we can see that many of the glaciers are in disequilibrium. We do not need to estimate the future.

    On #7 I will more exactly reproduce the picture when I visit the Lower Curtis Glacier this summer, 99 years after the previous picture. Focus on the terminus area and the change is evident.

    Comment by mauri pelto — 25 May 2007 @ 6:37 AM

  19. On #9 since I have included every glacier with reliable data in North America I have not cherry picked. This is a regional focus, though if you look at the cumulative balance of the WMGS for the globe you will see an almost identical graph. I do not go back to 1950 because mass balance was measured on only one glacier that year. In terms of continuous measurements only two Lemon Creek and South Cascade were begun in the 1950’s. The source of the data is the WGMS for all but Lemon Creek Glacier. All of the mass balance data has been published for these glaciers. I measure the North Cascade glaciers except for South Cascade Glacier.

    #15 The Swiss site is excellent. No other nation can match their program from annual terminus position measurement. The trends seen their are similar to the North Cascades. The glaciers are somewhat larger, with higher elevation accumulation zones with respect to the termini,and as a result with current climate more should be able to retreat to a new point of equilibrium.

    Comment by mauri pelto — 25 May 2007 @ 6:44 AM

  20. With respect to #9 I am only focussing on a region, I am not trying to make a global statement. Since I have utilized data from every glacier with consistent reliable data in western North America, cherry picking did not occur. I focus on this region, becuase I measure the mass balance of 11 of theses glaciers, it is what I know. We too often hear second hand about what is observed. I thought it important to share first hand observations and explanations. In 1950 only one glacier in North America was assessed for mass balance, and that glacier is not reported here. By 1960 measurements had begun on Lemon Creek and South Cascade glacier.

    The link in #16 illustrates the similar cumulative mass balance trend for the globe to Western North America.

    The Swiss as noted in #15 have the best alpine glacier monitoring program of any nation. There annual terminus surveys provide an amazing data set. In 2006 it was 84 retreating, and one advancing, cherry pick that.

    A good example of a glacier that will be more resilent to current climate change is Glacier du Brenay. Note in this picture the low elevation terminus lacking crevassing and looking stagnant. The Brenay will lose this section of the glacier with present climate. however, then there is an icefall separating the terminus-from the accumulation area. This helps separate the glacier dynamically and also means the accumulation zone is that much higher versus the remainder of the glacier, making this glacier more likely to survive. Brenay. Compare this to the Foss Glacier Foss

    Comment by mauri pelto — 25 May 2007 @ 7:24 AM

  21. Re #6, you’ll be happy to see this report:
    Climatologists Secure Funding To Breed Glaciers In Captivity


    Comment by Gerry Beauregard — 25 May 2007 @ 9:17 AM

  22. To the author: Is there any information on the latitude of the glaciers studied here? Is there any relationship between latitude and which glaciers are and are not in equilibrium?

    Global Climate Change happens on a global scale, but not homogeneously. The higher the latitude, the more drastic the effect, meaning the polar regions should experience a more drastic overall temperature increase than the equatorial regions. I am wondering if this is found in any of the evidence quoted above.

    In response to #3 and #4: It is important to understand the difference between the 2 types of glaciers in the world. Alpine glaciers, being discussed here, are glaciers located in mountainous regions such as the Cascades, the Alps (their namesake), and others. These glaciers operate in a wholly different way than do Continental Glaciers which cover large areas of a continent such as Greenland or the Arctic regions.

    Alpine glaciers are a great indicator of change as they are smaller in volume, and have the above mentioned ablation and accumulation zones, and equilibrium line, which we see shifting.

    In response to #14: Relating Global Climate Change to Continental Drift as an argument against taking action on the issue is a poor argument. Continental drift is a natural process which has literally been going on since the creation of Earth (however you believe this happened). Earth’s current observed climate changes are most definitely manmade.

    Comment by Agatha Wein — 25 May 2007 @ 2:07 PM

  23. Robert A. Rohde (#16) wrote:

    Re: #3, “Mass balance” as a measurement means the change in the average thickness of the glacier after correcting for variations in the density of the snow/ice. A value of -0.35 m/a means that averaged over its whole surface area the glacier is effectively thinning at a rate of 0.35 meters per year (“a” is for “annum”). Depending on context it may be expressed as meters water equivalent (mwe) or meters ice equivalent, but in each case the scientist making the measurement attempts to avoid the different densities of snow and ice by expressing everything in terms of the thickness that would be seen if all the material were fully compressed.

    Thank you for the explanation.

    This was something I often wondered about, especially with new ice or snow. Obviously it would be less compact and would be far more susceptible to melt in the future. But I suppose the water-equivilent in the essay should have been a dead give-away.

    Comment by Timothy Chase — 25 May 2007 @ 2:50 PM

  24. Re #18.

    Why breed glaciers in captivity when cold snowy surfaces is perfect for breeding artifical fog.

    Comment by Per.O.H — 25 May 2007 @ 5:09 PM

  25. Agatha you might expect a latitudinal gradient since it is often noted that warming has been more substantial at the poles. However, in this data set the two glaciers with the poorest mass balance are in BC in the middle latitudinally, the third poorest mass balance glacier is the South Cascade one of the more southerly glaciers. The trend globally is not decreasing mass balances at higher latitude in the WGMS data set either. One reason may be exemplified by Norway where a series of warm wet winters in the late eighties early nineties led to positive mass balances for many of their glaciers.

    Comment by mauri pelto — 25 May 2007 @ 6:46 PM

  26. Hank:
    Check the data. I did examine the data fairly closely. I am not relying on someone else and it is kind of rude to argue otherwise without first asking the question in a more polite or at least circumspect manner.

    More specifically if you look at both the Science paper and the Harvard Working Paper you will see the following:

    The Science article and Harvard AGQ paper indicate the following geographic distribution of glacial events:

    DJG – Daugaard Jensen Glacier – 5 events in 12 years – 8 in Analysis of Glacial Quakes
    KG – Kangerdlugssaug Glacier – 61 events – 64 in AGQ
    HG – Helheim Glacier – 26 events – 49 in AGQ
    SG – South east Greenland – 6 events – 7 in AGQ
    JL – Jakobshavn Isbrae – 11 events – 13 in AGQ
    RI – Rinks Isbrae – 10 events – 10 in AGQ
    HG – Northwest Greenland glaciers – 17 events – 33 in Analysis of Glacial Quakes

    I do not understand the reason for the difference in these numbers between the two papers but that does not bear on the major point at issue.

    The Science article goes on to note that ” a part of the increase in the number of glacial quakes is due to the occurrence of more than two dozen of these quakes in 2000 to 2005 at the northwest Greenland glaciers, where only one event (in 1995) had previously been observed.” (p1757)

    Now Tsai and Ekstrom also say in the earlier paper:
    “Some regions (e.g., region K) are consistent with a constant number of events per year (emphasis added) whereas other regions (e.g., region NWG) have had an unmistakable dramatic increase during the same time period.”page 10 Analysis of Glacial Quakes. You use the same quotation but apparently did not check to see just how many quakes occurred in the NWG and RI glacier complexes. I did and the authors statement is IMHO misleading.

    NWG and RI glacier complexes account for 43 of 182 or 27 of 136. The net increase in earthquakes from 2000 to 2005 is 51 out of a total of 182. Obviously if all but one of the 43 NWG/RI GQs occurred in this period we have the overwhelming percentage (42 of 51 or 80%) of the increase coming from 2 glacier complexes in Greenland. If this is true, then the numbers are such that whatever seems to be happening is not a Greenland event but a Northwest Greenland event and should be interpreted as such.

    Do you interpret these data differently? If not, I accept your apology.

    Comment by bjc — 25 May 2007 @ 7:29 PM

  27. Reference #22.

    I think that may be debatable. I mean, the core had to segregate from the crust before the continents could drift. So I suppose it depends, at which stage would you consider the earth to be created? Now with respect to climate, well that just refers to whatever is going on in various locales on the planet’s surface. Heck, we even speak of climate, and weather, on the gas giants, where the actual surface might be rather nebulous. I’d have to say that climate change on earth precedes continental drift.

    Comment by Harry — 25 May 2007 @ 9:35 PM

  28. Not only glaciers are retreating, frost lines are retreating as well. When antarctica becomes snow free and habitable, which country will claim it for its own? Sick people either get better, or die. What lies ahead for this very sick earth?

    Comment by Paul M — 25 May 2007 @ 10:22 PM

  29. Paul M:
    And exactly when will Antarctica become habitable?

    Comment by bjc — 26 May 2007 @ 4:56 AM

  30. Lets see how this works. Timothy shows enthusiasm for glaciers and interest in their retreat. bjc then responds with an attempted neutralizing comment, nit picking a breadcrumb regarding the increase frequency of earth tremors induced by moving glaciers. Cohort or dobbleganger “Harry” then chimes in with a snarky remark regarding Stefan’s pronouncement about climate change. Hank pounces on bjc for the neutralizing comment. bjc defends the neutralizing comment with interpretations resembling squid ink. bjc, feeling cocky, then asks when Antarctica will be habitable. Could bjc perhaps be with the Competitive Enterprise Institute? CEI.. now that is a choice piece of truth speak for you. Not much competitive about rebuilding the oil monopolies now, is there?
    Just a bit of attempted humor for a beautiful, WARM, Saturday morning!

    Comment by Skeptic Tracker — 26 May 2007 @ 6:43 AM

  31. Note the comments don’t appear as they are made, they end up in timestamp order but may not appear that way for a day or two if the hosts are busy; some pass the automatic filters, some get reviewed faster. The whole Greenland digression is as Dr. Pielto noted early on covered in other topics. My apology to Dr. Pielto; I’ll follow that up elsewhere if there’s news. My posting was made before I saw this:

    >plenty of posts in Realclimate focus on Greenland, but the topic here is not an ice sheet, but small alpine glaciers.

    Comment by Hank Roberts — 26 May 2007 @ 11:38 AM

  32. Skeptic Tracker:
    I assume to justify your comments you have read both Ekstrom papers and have a point of view regarding their findings? But then if you had read them, my comments would look less like “squid ink”. Hank, at least, had made the effort to read them.


    Comment by bjc — 26 May 2007 @ 11:40 AM

  33. Dr. Pielto, trying to bring this back to your discussion — where are you going next?

    Comment by Hank Roberts — 26 May 2007 @ 12:13 PM

  34. Hank:
    It would be polite to let me know if you reassessed your position rather than taking a shot and then departing. Is there another thread you want to continue on?

    Comment by bjc — 26 May 2007 @ 12:30 PM

  35. Today’s Editor:
    It is fair enough that you edited out parts of my last comment in response to Skeptic Tracker. However, I would have preferred it if Skeptic Tracker’s comments had been dealt with in a similar fashion and in accordance with your comment policy. Skeptic Tracker’s comments, left as written, are clearly an ad hominem and entirely without foundation, i.e., I have never had anything to do with any think tank or interest group. I had merely pointed out that an earlier assertion that Ekstrom’s Science paper on the recent increasing frequency of glacial quakes does not pertain to Greenland as a whole. 80% of the increase in these newly identified seismic events took place in two proximate glacier complexes in NW Greenland. I do not know whether this is a widely recognized fact or not – but given the visibility of a paper in Science I felt it was appropriate to point this out.
    You have my email. If I have transgressed in some way, please let me know. I certainly prefer a civilized and respectful discussion forum.

    Comment by bjc — 26 May 2007 @ 1:23 PM

  36. I was wondering if Glaciers where ever considered as giant thermometers, in a real sense, with thermistors embedded in them as a way to determine temperature vs melting? There must be a critical core temperature not achieved after warm winters which should help accelerate melting.

    Comment by wayne davidson — 26 May 2007 @ 1:31 PM

  37. bjc– you ignored the time sequence of events. Look back. Icequakes began in each area when the sea ice quit obstructing the outflowing ice. The process happened earlier on the southeast. Our hosts will open a topic when there’s new info, I trust. Endit.

    Comment by Hank Roberts — 26 May 2007 @ 1:34 PM

  38. I will be back in the field measuring mass balance this summer on 10 of the above glaciers. I have forecasted a negative balance year for them based on the Pacific Decadal Oscillatiion and the El Nino Southern Osciallation index values for the winter. I will also being mapping an area that just lost its glacier.

    Comment by mauri pelto — 26 May 2007 @ 1:42 PM

  39. One problem with glaciers that is often picked up by the sceptics, is the behaviour of calving glaciers which is often out of phase with local climate. This allowed people like David Bellamy to cherry-pick calving glaciers from ice caps which weren’t particularly recessed, or were near their Neoglacial limits. This is a major problem in Patagonia where many glaciers on the western side of the icefields are tidewater calving, and those on the east side are lake-calving. Both behave differently.

    Comment by stephan harrison — 26 May 2007 @ 2:50 PM

  40. #30

    I suppose the analysis was fun for you. I’m actually just a random contrarian, as opposed to a dogmatist. (Let’s make it illegal and have trials for people who disagree with us about climate change.) I don’t know those other folks, and they probably don’t want to know me.

    I’m still fascinated by the concept that an increase in CO2 will lead to a decrease in the cooling effect of CO2 (supposedly emission to space). It makes me wonder what those models will show if all of the atmospheric CO2 is removed. Will that cause warming because there is no longer any CO2 present to radiate?

    Obviously, this is way off topic. I would be mildly surprised if the glacier measurements in the main thread are incorrect. It certainly does appear that many glaciers are retreating. I freely admit, I couldn’t see any fun ways to poke at that, and being an avid contrarian, and more or less oblivious to anyone’s thoughts but my own, I had to strike out in a different direction.

    If another 50 years go by, and no cooling cycle begins, I suppose I will have been incorrect. I’d be surprised, but willing to admit to being incorrect.

    With respect to retreating glaciers, it appears to be a natural part of the temperature regulation system of the planet. It is quite nice sometimes to live on a planet that has three phases of water present on its surface and in its atmosphere. Given the tremendous non-equilibrium and continuously changing forces that set the rough dial of planetary temperature (sun, gravitational pull of other bodies, you can probably come up with a few more on your own), it is good that water can so facilely change phases to offset some of the more dramatic and unfriendly temperature changes that would occur otherwise. Water makes a great heat conveyor belt to transport energy around the globe, and up to the top of the troposphere when the surface warms. It can respond to dampen the effects of increased or decreased temperatures. This is really quite remarkable. Since there is no switch to turn it off when it’s done, oscillation is to be expected.

    Comment by Harry — 26 May 2007 @ 3:24 PM

  41. bjc,
    Lighten up man or woman! I said this was an attempt at humor! As a matter of fact I did read the Tsai and Ekstrom paper at the link you provided, and I have a problem with your statement to Timothy, right off the bat. That paper clearly states that in region H “since 2000 there has been a significant increase to 10 or more events per year”. And region H is in southwest Greenland. So where do you come off saying that the increase is localized to the North West? The paper also states “A second temporal trend in the data is the dramatic increase in the total number of events since
    2002, with more events detected in each successive year since 2002 and resulting in more than
    twice as many events in 2005 as compared with any year prior to 2003.” So I will charitably suggest that perhaps you, bjc, did not read the article. BTW, when I had my first job in the business world with my new technical degree, many many years ago, my mentor dissected the word assume and explained why it was such a weak word to use. Didn’t anyone ever do that for you? Anyway, I stand by my squid ink analogy. It wasn’t an insult, just a frank statement of the type of defense of your position that you appeared to have used. Your statement about the localization of glacier quakes just seems off the wall, if you know what I mean. Kind of like re-arranging deck chairs on the Titanic. I hope you have grown a sense of humor since this morning! Cheers!!!

    Comment by Skeptic Tracker — 26 May 2007 @ 6:11 PM

  42. I’m still fascinated by the concept that an increase in CO2 will lead to a decrease in the cooling effect of CO2 (supposedly emission to space).

    Good! Being fascinated by physics might actually motivate you to learn some!

    With respect to retreating glaciers, it appears to be a natural part of the temperature regulation system of the planet. It is quite nice sometimes to live on a planet that has three phases of water present on its surface and in its atmosphere.

    Oh lord, the anthropic principle so beloved of creationists visits climate science, though in a weakened form.

    Comment by dhogaza — 26 May 2007 @ 11:59 PM

  43. You are correct that region H (SE Greenland) had an increase in earthquakes notably in 2004 and 2005. Region NG in NW Greenland has also had an increase. Lumping region H with the other three Eastern Greenland complexes was a mistake on my part.
    A closer look at the paper reveals that out of the 7 glacier complexes noted only these two regions had an actual noticeable increase in these quakes since 2000 compared to 1993 through 1999. Region H, accounts for an increase over expected number of 28 quakes for 2000 through 2005. Region NG accounts for 31 of the quakes. These two complexes account for all of the increase in frequency of glacial quakes.

    If we take Greenland as a whole, the average number of quakes across the entire 7 complexes was 10 per year from 1993 through 2001. Given that there were a total of 92 quakes from 2002 through 2005, that leaves a net increase over past trends of 52. During this shorter period, Region H had an increase over trend of 29 and Region NG an increase over trend of 27. There was a slight decrease in the other 5 Regions.

    So while you are correct that my original assertion that the increase was only in NW Greenland was wrong, the data still does not justify the assertion that the increase applies to all of Greenland. The original title of the Science article, Seasonality and Increasing Frequency of Greenland Glacial Earthquakes, is somewhat misleading.

    Comment by bjc — 27 May 2007 @ 12:21 AM

  44. Stephen good point on the calving glaciers. The North American mass balance data set here has no calving glaciers. Glacier dynamics is much more important to glacier behavior on calving glaciers. I missed #1, there is no global time series of the change in ice and glacier volume or area. We can begun one with the satellite era and an inventory has been completed by some nations for the 1970’s period. To get a better view of Lemon Creek Glacier and its neighbors take a look at the google earth tour showing change over the last 50 years at GE Tour, the file link is near the end of the first paragraph.

    Comment by mauri pelto — 27 May 2007 @ 6:10 AM

  45. The book Glaciers by Hambrey & Alean (2004) has a table showing the distribution of glacierized area of the world (from World Glacier Montioring Service, 1989). It has 8 regions along with the area covered, but being it is 1989 data, it is kind of dated.

    I would be interested in seeing more data of the Tibetan plateau glaciers since the rate of melt I see stated is like 7% a year. I have read the Yangtze river is likely to have a severe flood this year because of the melting.

    Comment by Jim Crabtree — 27 May 2007 @ 9:59 AM

  46. re: #45
    “CHINA has lost 3,248 square kilometers of its glaciers over the past 40 years which is 5.5 percent of the country’s total glacier cover, according to the country’s land watchdog.

    China now has 46,298 glaciers, with a total area of 59,406 square kilometers, storing 5,590 cubic kilometers of ice, according to the country’s most authoritative glacier data base.

    The average ice level also dropped 6.5 meters in the same period.”

    I don’t know how they get these numbers to 5 significant digits :-), but here are some relevant pages of the Chinese Glacier Inventory:

    It’s not as accessible as the Swiss site, but it’s clear that they are trying very hard, as well they might, because they have additional serious hydrology issues ahead, dwarfing the (very real) ones we have here in California.

    I’ve done the Yangtze boat trip (Wuhan–>Chongqing, highly recommended, if you haven’t done it; at least a lot of that trip doesn’t have to deal with air pollution, but go soon). Wuhan: Imagine a giant New Orleans, (but without hurricanes, at least), many old levees, ~8M people, and criss-crossed by big flood-prone rivers.

    The scale of efforts needed in dealing with *that* river are rather awesome, already, and let’s hope the Three Gorges Dam actually works, because Wuhan already has enough flooding problems:

    Comment by John Mashey — 27 May 2007 @ 5:17 PM

  47. From Rapid disintegration of Alpine glaciers observed with satellite data, Paul et al GRL 2004

    “Highly individual and non-uniform changes in glacier geometry (disintegration) indicate a massive down-wasting rather than a dynamic response to a changed climate. Our results imply stronger ongoing glacier retreat than assumed so far and a probable further enhancement of glacier disintegration by positive feedbacks.”

    It seems to me that skeptics don’t like discussing this topic, probably because it is such hard proof of global warming. They’d rather talk about icequakes in Greenland, apparently… Speaking of skeptics, it’s worth raising the issue of Kilimanjaro – a good discussion from National Geographic is here (2003). As some may recall, Pat Michaels tried to claim that Kilimanjaro’s alpine glacier retreat had nothing to do with global warming in 2002. The more reasonable explanation is that intensified convection over the Atlantic and Indian Oceans is altering the African monsoon and delivering less precipitation to the continent – which, in combination with rising surface temperatures, presents a double whammy to Africa.

    An associated issue is the melting of alpine permafrost, which is the glue that holds many of the rock walls in the Alps, Himalayas and Andes together. There seem to be fewer studies on this, but there is the European Permafrost Monitoring Network and their PACE Permafrost Boreholes. Massive landslides are highly likely.

    Mountaineers and mountain dwellers have been noticing many changes. For example, see here, and here.

    Finally, Palisade Glacier is the largest glacier in California and the southernmost one in the United States – and it also has been thinning recently.

    Comment by Ike Solem — 27 May 2007 @ 5:45 PM

  48. The number of glaciers and glacier area reported in China is likely a reliable number, not that you can take it exactly as stated to the bank. However, the 6.5 m of ice thinning in the last 40 years, is not a dependable number at all. The Chinese did not have good maps of the surface elevations of the glaciers 40 years ago, nor have they measured the mass balance of even one glacier over a 40 year span. Thus, I guarantee you this number on thinning is worthless. In terms of excess glacier melting causing flooding. Glacier melting is not something that has huge spikes that tend to cause flooding. The loss of glaciers lead to led storage of spring snowmelt leading to more spring flood potential. But the rapid melt is not a cause of flooding anywhere, unless a glacier dammed lake is involved.

    Comment by mauri pelto — 27 May 2007 @ 5:47 PM

  49. re: #48
    Thanks for the calibration of numbers, I did wonder about 6.5 as well…

    re: glacier melt: sorry for any ambiguity: I never meant to imply that glacier melt was causing the floods directly, it was more as an obvious indicator of changes in the local hydrology, which at least seemed likely to exacerbate the existing snowmelt pulse problems they already have. offhand, I can’t think of any reason why shrinking Himalayan glaciers would be very helpful to Asia.

    Comment by John Mashey — 27 May 2007 @ 6:53 PM

  50. FWIW, I believe that there is global warming and that glaciers as a result are retreating. My comments about icequakes were strictly in response to someone else bring the topic up as if it had the same precision and implications as Dr. Pelto’s survey of NA glaciers.

    Dr. Pelto – is there a way of estimating the response time of NA glaciers to above or below average temperatures/precipitation? Would 2 or 3 cooler years in a row be sufficient or will it need a decade?

    Comment by bjc — 27 May 2007 @ 6:55 PM

  51. #46: John:

    Thanks for the info.

    # 48: Mauri:

    This was not my original source, but it says the same thing.

    “Rapidly melting glaciers on the Qinghai-Tibet Plateau could cause a major flood on the Yangtze River this summer, says Cai Qihua, director of Yangtze River Water Resources Committee.

    We should be vigilant for a comparatively big flood on the Yangtze,” said Cai, emphasizing that meteorological conditions are similar to those of 1998 when a major flood killed more than 1,000 people.

    With plenty of snow on the Qinghai-Tibet plateau, higher than normal temperatures could lead to rapid melting and run off, said Cai.

    Meanwhile, water levels have remained low along the entire mainstream of the Yangtze and its tributaries since last winter and many areas in the Yangtze River Valley are suffering drought.

    No serious floods have occurred on the Yangtze since 1998, so it is quite possible for a major one on the river according the natural cycle,” said Cai.

    She also noted that the damage that might be caused by rainstorms and possible floods and other natural disasters in the Yangtze River Valley should not be underestimated.”

    On reading it closer, the third statement says it is a lot of snow that is also adding to the problem. I understand there are over 40 large glacial lakes in the Himalayas that are going to be causing some serious problems in the not too far distant future. Thanks for clearing up the misconception I had about glacier melting and flooding.

    Comment by Jim Crabtree — 27 May 2007 @ 7:08 PM

  52. Re # 40 Harry,
    I’m curious: Do you critique the arguments put forth by AGW skeptics and denialists as carefully as you do the arguments of mainstream climatologists that AGW is real?

    And if the scientific consensus was that there is NO anthropodenic global warming, would you, as a random contrarian, argue that AGW IS occuring?

    Comment by Chuck Booth — 27 May 2007 @ 9:44 PM

  53. #50- The response time of glaciers is something that Tomas Johannesson of Iceland first quantified. The faster a glacier flows, the smaller it is and the higher the amount of ablation and accumulation the faster it responds. In the North Cascades for example a climate shift toward wetter cooler conditions began in 1946, and by 1949 the first glacier to advance the Coleman Glacier on Mount Baker was noted. By 1956 all of the ten main glaciers on the mountain were advancing so in that case 3-10 years response. Similarly in 1977 a shift to a warmer-drier climate occurred, this led to retreat of all of the above glaciers by 1988, within 12 years. Further details on response time, and why not all of the glaciers advanced after 1946 are at J of Glaciology paper .

    Comment by mauri pelto — 28 May 2007 @ 6:28 AM

  54. I found Mauri Pelto’s guest comment excellent (missing only the definition of melt rate m/a supplied later). It seems to support much of what I have read. I recommend Mark Bowen’s book “Thin Ice” largely describing the work of Lonnie Thompson who has been all over the low and mid latitudes gathering ice cores and has seen glaciers shrinking. Then there are the continuing reports from mountineers and ice climbers reporting the same. Then there is Gore’s selection of glaciers from all over the globe. If that is “cheery picking” it is one hell of a tree. I believe the IPCC report (WG2) put the Himalayan Glaicers as the fastest retreating glaciers in the world and are expected to be 80% gone by 2030. There is also a report in Bowen’s book that the Chinese expect all their glaciers to be gone by the end of the century. This is a world wide problem.The alpine glacier has been called the canary in the coal mine. How dead does that canary have to get before folks realize we have a major problem? – George C.

    Comment by George Collins — 28 May 2007 @ 6:47 AM

  55. #50, #53, #54

    bjc #50: if you look at the Holzhauser paper I mentioned in #15:

    They think the Great Aletsch glacier has a reaction time of about 24 years (Ts in Prof. Pelto’s paper) and the Gorner glacier 19 years, but the response time (Tm) is much longer, on the order of 50-100 years. So, they say:
    “The present-day position of the glacier front is therefore a reflection of the climactic conditions of past decades.”

    Putting all these together, glaciers act as a good set of time-filters. Some respond fairly quickly, and others take much longer to even notice a change, so there is a *natural* mechanism that smooths out gyrations of different durations, depending on the characteristics of the glacier. One doesn’t need to calculate N-year rolling averages, because the glaciers do it themselves :-)

    It is worth looking at the chart of Great Aletsch:

    and read the actual data:

    This is relatively smooth retreat, with recent acceleration reflecting the warming of the 1980s, I guess. If I understand this, Aletsch has barely noticed the last decade’s heat yet.

    It is also worth looking at:
    which sorts the Swiss glaciers by increasing length. The shorter ones tend to have much quicker advance/retreat jiggles, whereas the longer ones have filtered that out. Of course, there are variations, for the sorts of reasons described in Prof. Pelto’s nice paper in #53.

    Anyway, it’s quite useful to study these things … while they last.

    Comment by John Mashey — 29 May 2007 @ 1:50 PM

  56. Re Comment #47,
    I was going to mention Palisade Glacier, but you beat me to it! Of the glaciers in the Sierra Nevada, that is the only appreciable one left. There are only a few sets of air photos (USGS and privately), but it’s reasonable to estimate ~30% mass loss since mid-century. The SNOTEL records are really key to that study- and yes, we did use snow-water equivalent. A very interesting neighboring glacier just to the south appears to react more slowly, but it is mantled with a thick cover of rock debris (~1m).

    Comment by ajg — 29 May 2007 @ 7:50 PM

  57. As some may recall, Pat Michaels tried to claim that Kilimanjaro’s alpine glacier retreat had nothing to do with global warming in 2002. The more reasonable explanation is that intensified convection over the Atlantic and Indian Oceans is altering the African monsoon and delivering less precipitation to the continent – which, in combination with rising surface temperatures, presents a double whammy to power leveling

    I would have preferred it if Skeptic Tracker’s comments had been dealt with in a similar fashion and in accordance with your comment policy. Skeptic Tracker’s comments, left as written, are clearly an ad hominem and entirely without foundation, i.e., I have never had anything to do with any think tank or interest group

    Comment by wow power leveling — 31 May 2007 @ 4:30 AM

  58. I can’t let the discussion end on that note. On the glacier noted above in western North America, the declining mass balance in recent years has been in spite of higher precipitation rates. Thus, the negative balances fall squarely on the shoulders of higher temperatures. If you are interested in a map based view of temperature changes examine this Goolge Earth file that has over 6000 stations with graphs of temp. changes for each.

    Comment by mauri pelto — 1 Jun 2007 @ 11:31 AM

  59. Mauri,

    If you are accept that the glacier melting is due to CO2, what do you suggest we do? Reduce atmospheric CO2 instead of increasing it? That would seem to be the only solution, since we know at this level of CO2 the glaciers will continue to melt, and if we continue burning fossil fuels then they will melt faster.

    When are you scientists going to admit that we have passed the tipping point?

    When are you scientists going to tell GWB that his call to postpone action for another 18 months means that we will have another 18 months of his destruction to repair after he has gone?

    Comment by Alastair McDonald — 1 Jun 2007 @ 3:09 PM

  60. Dr. Peito, perhaps the Contributors here can keep the discussion open but set a (very, very) high bar on approving postings to it, so you can continue to provide information as you do your research. (Gavin, consider this a plea.)

    Hoping for a “scientist talk, we read” approach to this, and other scientist-specific topics, on a selective basis, I am.

    Comment by Hank Roberts — 1 Jun 2007 @ 4:41 PM

  61. Sorry the link for the GISS global temperature stations is GISS

    Comment by mauri pelto — 1 Jun 2007 @ 5:28 PM

  62. #60 Hank Roberts

    I’m with you on this one – it would be nice to see the comments attached to articles consisting of Q&A arising from the article (with answers supplied by the climate scientists) and perhaps a separate area for discussion by the variously informed.

    Comment by SomeBeans — 2 Jun 2007 @ 1:38 AM

  63. Dear Dr Peito,

    You wrote “The question is determining which glaciers are merely out of equilibrium and can retreat to a position of equilibrium, and which are in complete disequilibrium and will melt away?”

    In the spirit of Hank’s #60 post, can you make an estimate about how many more glaciers will have changed from a state of “out of equilibrium” to “complete disequilibrium” duting the next 18 months?

    Regards, Alastair.

    Comment by Alastair McDonald — 2 Jun 2007 @ 9:15 AM

  64. In terms of continuous measurements only two Lemon Creek and South Cascade were begun in the 1950’s.

    Pelto, thanks for the insightful post. What response would you give to someone that claims this USGS website on the South Cascade as proof that global warming happened started before man? This USGS website seems to contradict your claims.

    Comment by wacki — 2 Jun 2007 @ 12:38 PM

  65. Alastair, I don’t understand why you make a habit of attacking scientists who are simply trying to present an accurate picture of their research to the public. As far as your demand for an 18 month prognosis from ‘you scientists’, keep in mind that there are unavoidable uncertainties in the near-term climate predictions – for example, we could have another Pinatubo three months from now that would result in a short-term aerosol cooling.

    Secondly, what do you mean by “out of equilibrium” vs. “complete disequilibrium”? It’s obvious that alpine glaciers all over the world are melting, and it appears that the main culprit is increased surface air temperature at higher altitudes, though changes in precipitation play a role in some areas as well.

    I think your energy would be better spent trying to convince investors and politicians to begin truly large-scale renewable energy projects, as well as to institute a hefty carbon emissions tax.

    RE#57, on Kilimanjaro, the facts seem to be that Over the 20th century, the areal extent of Kilimanjaro’s ice fields has decreased ~80%, and if current climatological conditions persist, the remaining ice fields are likely to disappear between 2015 and 2020. (from Thompson et al 2002)

    So, there appears to be some debate as to what the causes of this particular glacial retreat are, and not much of it seems convincing. It ties into the question of what is causing the expansion of the subtropical dry zones in Africa (ongoing drought since the 70s). Cullen et. al GRL 2006 divides the mountain into ‘slope’ and ‘plateau’ glaciers, and claim that the fate of glaciers on Kilimanjaro has nothing to do with modern climate change, since there was ‘rapid retreat of slope glaciers in the early 20th century’.

    This may not be entirely fair – but these authors claim that changes in the large-scale circulation dating back to the 19th century are responsible for the glacier retreat on Kilimanjaro – which just seems to be unsupported.

    This paper has been uncritically trumpeted by Roger Pielke Sr., the World Climate Report, and other skeptic web sites… which have a long history of selectively choosing only those papers which support their views. However, the fact is that Kilimanjaro has been glaciated throughout the entire Holocene, and yet it is predicted to be bare within a few decades. Despite this, the contrarians have loudly proclaimed that glacial retreat on Kilimanjaro has nothing to do with global warming, based on a handful of papers by the same authors.

    This claim has been widely used to attack Al Gore’s “An Inconvenient Truth”, so it seems worth rebutting.

    There are really just three positions that the skeptics hold. First was “global warming isn’t happening”, and then it was “global warming is happeing due to strictly natural causes”, and the next one will be “yes, we are causing global warming, but it’s going to be a good thing!”.

    Comment by Ike Solem — 2 Jun 2007 @ 4:38 PM

  66. Ah, Ike, Dr. Pelto said he’s here to talk about that sort of question. Look again at the original post, and Alastair’s question.

    Dr. P: “I get asked at least once a day about the future prognosis for alpine glaciers and whether they have a future. I will focus here on North American glaciers whose mass balance measurements in the West from 1984-2005 indicate a declining trend. …. The question is determining which glaciers are merely out of equilibrium and can retreat to a position of equilibrium, and which are in complete disequilibrium and will melt away? Let me explain.”

    Backing, slowly, away from the keyboard myself here …..

    Comment by Hank Roberts — 2 Jun 2007 @ 8:48 PM

  67. #64 In the paper on glacier response time, I note that the South Cascade Glacier is slow to respond to climate and never fully adjusted to the post Little Ice Age climate before the current warming began. However, note that the it is the USGS mass balance record that shows it is the current warming that is the problem. Note the mean annual balance for the glacier from 1959-1976 -0.43 m/a, from 1977-1997 -0.84 m/a was and from 1998-2005 was -1.2 m/a. Thus as the graph for all three USGS glacier show and the cumulative balance curves in this commentary indicate mass balance is becoming more negative. On South Cascade Glacier this is after getting rid of the lowest elevation, highest melting section it is doing even worse. SC Glacier

    #63 The present climate is not new, we have experienced the current warm conditions for two decades. Thus, either a glacier is in disequilibrium or it is not, 18 months is not going to change that. A glacier may disappear in that period. The point is we can diagnose glaciers in disequilibrium, before they are nearly gone. We do not then have to reexamine every year to see if they have changed, glacier equilibrium is a longer term process.

    Comment by mauri pelto — 3 Jun 2007 @ 11:05 AM

  68. Thanks Hank for the reminder.

    Maybe the question is this – if these notions of glacial equilibriuma and disequilibrium are good descriptions of the alpine glacier system, do they also apply to larger ice masses like Greenland and the West Antarctic ice sheet? It seems that glaciologists were predicting that these systems were stable a decade or so ago, but now it looks like some kind of dynamic response is occurring – something that no glaciologist predicted.

    I suppose my question for Dr. Pelto is whether or not similar issues arise in the case of alpine glaciers?

    Comment by Ike Solem — 3 Jun 2007 @ 8:05 PM

  69. The reason we often use smaller alpine glaciers as reliable climate indicators is because their dynamics are simple. Thus, their response is directly to climate and glacier dynamics plays little role. That is obviously not the case. Dynamics become much more important if a glacier is calving, if it is not a temperate glacier, that is at the pressure melting point throughout and if it has a buttressing ice shelf. I would argue having worked on Pine Island Glacier and Jakobshavns Glacier 20 years ago, that what we are seeing today, was anticipated and was even the basis for the funding we used. That is we (U of Maine) were investigating the speed of Jakobshavns and measuring its characteristics to determine the role of various forces, including the water supply. The latter was expected to increase with warming and was of concern. Hence, the term Jakobshavns Effect was coined by Terry Hughes. Further Pine Island was seen as the weak underbelly of the West Antarctic Ice Sheet by Hughes and Thomas (NASA), and that acceleration and grounding line retreat could occur due to thinning from enhanced calving or more basal melting. The speed with which the processes would act were of course not known. But the processes were described by these two researchers 20 years ago.

    Comment by mauri pelto — 4 Jun 2007 @ 7:26 AM

  70. Has nobody ever heard of the Thermal Haline Circulation function of Global weather? This is a long term feed-back mechanism of global climate control…..also………….All official temp. readings have been taken for about 110 years in the US……….and in the last 100 years what has happened to those locations, that is more than enought to account for the less than 1 degree warming? Ever hear of Thermal Mass….???? as in paving….buildings…etc………I live in the country……about 20 miles from the city…..I have a very accurate weather gathering station… temp. are at least always 3 to 8 degrees cooler………DUH,,,,, I am located in a setting much like the weather gathering stations of the past…before they became so “Built Around” ……Global warming freeks use the excuse…..I repeat “Excuse” that there is a “FORMULA” for adjusting for that fact…..LOL….Give me a break…………with a diff. of less that 1 degree in the last 100 years……that is a joke !!…………WHY DOSE NO SCIENTIST EVER BRING UP THE FACTS???????????????????????

    Comment by Gary Tucker — 6 Jun 2007 @ 8:10 PM

  71. Thanks for the historical background. I suppose the correct interpretation is that climate models have a difficult time dealing with the many complex processes involved in the cryosphere, and so did not take into account processes that had indeed already been described by glaciologists.

    Comment by Ike Solem — 6 Jun 2007 @ 9:18 PM

  72. Re # 70 Perhaps because all those smarty-pants climatalogists and oceanographers with their lofty university degrees just don’t know as much as you?

    Comment by Chuck Booth — 6 Jun 2007 @ 10:02 PM

  73. Re #70 — Please note that global warming is also taking place in sea surface temperatures. It’s very difficult to attribute that to an urban heat island effect, because there are so few cities on the surface of the sea.

    The UHI accounts for, at most, 15% or so of measured global warming, and that’s being extremely generous.

    Comment by Barton Paul Levenson — 7 Jun 2007 @ 8:03 AM

  74. RE: #70.

    Not to be rude, but who exactly do you think analyzes and describes how the ocean functions in the climate system? Perhaps the very same group of scientists you criticize? Do you really honestly think no one accounts for that, and that you have uncovered some ground-breaking piece of unforeseen evidence? I suppose if climate scientists simply looked at the thermometer nailed to the birdfeeder in your backyard, they’d be forced to recant all of their work. Or perhaps you should check out the link titled “Oceans” on the right-hand side bar. May I also suggest the use of the spell-checker function on your computer?

    Comment by ajg — 7 Jun 2007 @ 3:57 PM

  75. #70 Gary, I can only assume that your isolation has kept you from reading relevant journals on climat and oceanography. Otherwise I could not excuse your ignorance of the fact that such effects are in fact discussed seriously by scientists every day.

    Comment by ray ladbury — 7 Jun 2007 @ 5:41 PM

  76. Please don’t feed trolls. Let the topic be for Dr. Pelto to explain his work.

    Comment by Hank Roberts — 7 Jun 2007 @ 6:11 PM

  77. Mauri-
    Do the alpine glaciers in the Cascades show an ELA change with latitude or longitude? I’m a little more familiar with the systematic ELA variations in the Sierra, but I’ve always wondered about the North Cascades and Olympics. Any thoughts?

    Comment by ajg — 7 Jun 2007 @ 7:19 PM

  78. These small glaciers do not have a true equilibrium line altitude. The accumulation zone is not typically a single contiguous area. If you look at the elevation of the mean glacier elevation you can see that change within the North Cascades. The bigger change is from west to east across the ranges precipitation divide. If you compare the ELA from Mount Rainier to Mount Baker you can see the latitudinal change. Mount Rainier ELA’s typically have been 2100 m, compared to 1800 m on Mount Baker 2 degree latitude north. The Olympics have similar ELA to the North Cascades.

    Comment by mauri pelto — 7 Jun 2007 @ 8:20 PM

  79. With such a short time span for your data. Do you think about what if this is cyclical. And we dont know enough to be making determinations of what is really happening ? Could it be as simple as the earth is 5 miles or 500 miles closer to the sun on average? Maybe the earth climate is on an up shift for temp. and will come back down in 50 years? The sky is falling is hard to swallowwhen this started out with a volcanic rock. Since then we have had how many ice ages ? In school we were taught another was coming. The problem here is we as humans are usually very short sighted and every little change in a very complex pond. We have 500 people saying why. I think if we focus on what is simple we will find something more likely. We are a spec in time on this planet. Lets not be to hasty in our speculations. Im not saying your wrong. Im saying at least leave room for something else. I am undecided. But talking in circles … lol…I would find it easier to believe the planet is a little farther or closer to the sun in its orbit than to blame a few degrees on us.

    Thanks for your time

    Comment by Brooks — 25 Jun 2007 @ 8:27 PM

  80. Re: #79 (Brooks)

    I would find it easier to believe the planet is a little farther or closer to the sun in its orbit than to blame a few degrees on us.

    Changes in earth’s orbit can indeed have a profound effect on climate. But earth is not “a little farther or closer to the sun…” The average distance earth-to-sun can be measured with amazing precision, and the changes of orbits under the perturbing influences of the other planets have been well understood for about 2 centuries.

    Changes in the eccentricity (degree of flattening) of earth’s orbit do effect the total energy we receive from the sun, but the change in average insolation is generally less than one half of one percent, and the cycle of eccentricity changes is extremely slow (about 100,000 years). Changes in the direction of earth’s spin axis, and the tilt of that axis, don’t effect the total sunlight we receive, but do effect the distribution of that energy; in particular, they effect how much goes to the polar (as opposed to equatorial) areas, and how solar energy is distributed throughout the year. This can effect the growth or decay of polar ice, and the “signature” of these cycles (about 41,000 years for the tilt angle cycle and 22,000 years for the axis direction cycle) are plainly visible in records of ice growth and decay during glaciations and deglaciations.

    The effect of changes in earth’s orbit are thoroughly well studied; the cycles which effect climate are often referred to as “Milankovitch cycles” (after the mathematician who argued strongly for their importance in driving ice ages).

    Comment by tamino — 25 Jun 2007 @ 9:26 PM

  81. i have been reading “Climate Change and Trace Gases”, Hansen et al., Phil. Trans. R. Soc. A (2007) v365, pp 1925-1954. I have not yet digested it fully, but two points struck me as relevant to this discussion
    1) the paleo record reflects the timescale of the forcings rather than the internal timescale of the icesheet melt. the rate of melting is not bounded above by the paleo record, the icesheets could melt much faster than the paleo indicates.
    2)albedo flip: Fig: 2 seems rather convincing. A model with albedo change included matches the Vostok record well…but with a sensitivity of 1.5C/(Wm^-2) rather than the 3/4 number, which does not include changes in surface properties.

    Hansen goes on to indicate that albedo flip is under way, as seen by the increasing summer melt in Greenland and Antarctica.

    A question i have is: what is the internal timescale for ice sheet melt ? i have heard that Prof. Alley is working on a model, but i have not seen any publication yet.


    Comment by sidd — 25 Jun 2007 @ 11:02 PM

  82. sidd (#81

    Hansen goes on to indicate that albedo flip is under way, as seen by the increasing summer melt in Greenland and Antarctica.

    I tend to put a fair amount of stock in what he says. Not that my opinion means that much, though.

    A question i have is: what is the internal timescale for ice sheet melt ? i have heard that Prof. Alley is working on a model, but i have not seen any publication yet.

    It is probable that they have gotten a little further than this might suggest:

    Report of the Workshop on Ice Sheet Modeling
    at the NOAA Geophysical Fluid Dynamics Laboratory
    8 January 2007

    … but there are undoubtedly a number of climatologists working in this area.

    Comment by Timothy Chase — 26 Jun 2007 @ 7:53 AM

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