Glacier Bay, Alaska

George posted up the following link as supposedly supporting Lonnie Thompson’s views on Quelccaya:

Early results on Reid Inlet, where Reid Glacier has now backed up out of the ocean, show that the glacier had retreated beyond where it is now more than 10,000 years ago, advanced to the sea by 8,000 years ago, again retreated beyond where it is now about 7,000 years ago, and the ice once again advanced to Reid Inlet beginning about 5,000 years ago.

I’m not sure how the quote supports his position. I haven’t seen any academic publications on the location in question, but collated a little information from abstracts of the authors to conferences over the past few years, showing a curious result.

In 2002, they pointed out that, in the past, the glacier advanced slowly and retreated rapidly:

Past observations of modern tidewater glaciers suggest that these glaciers advance quite slowly (single meters per year) compared to rapid and sometimes catastrophic glacial retreats (tidewater glaciers in Glacier Bay have retreated ~90km in 300 years, or 300 m/yr).

In 2003, they re-affirmed this and, based on radiocarbon dates, reported 4 periods of glacial advance, the most recent being ~1.6 to 1.2 Kyr BP.

Current understanding of the advance and retreat rates of tidewater glaciers suggests that while ice margins can retreat quite rapidly (km/yr), their advance is rather slow (m/yr). Our studies of the glacial history and interglacial climate of Glacier Bay in southeast Alaska indicate that past rates of ice margin advance were highly variable, including periods when ice advanced at rates equivalent to those during a rapid recession. We infer rates of advance during the Holocene from radiocarbon dates of tree stumps that were overridden as ice moved down-fjord. We have sampled over 100 stumps rooted in growth position, and dated their outer rings, which mark the death of the tree, using the AMS technique. In addition, the ages of about 100 logs in glacial deposits of moraines adjacent to the fjords also record approximate ice marginal positions. Our data cover the advance of ice from accumulation areas in the western Fairweather Range and eastern Takhinsha Range into lower Glacier Bay during four apparently distinct periods: ~ 9.5 to 6.0 K radiocarbon years BP, ~ 4.4 to 3.0 Kyr BP, ~2.4 to 2.0 Kyr BP, and ~1.6 to 1.2 Kyr BP.

In 2005, they said that the “most extensive Holocene advance occurred during the Little Ice Age” – a period not mentioned in the 2003 report.

Terminus positions of the tidewater glaciers in Glacier Bay are known reasonably well from radiocarbon dates on stumps rooted in growth position but overridden by advancing ice, and by limited stratigraphic data associated with them. The last glacial maximum (LGM) advance extended well beyond any Holocene position. The post-LGM rise in insolation and greenhouse gases was accompanied by retreat behind the present position prior to 12.5K C14 years BP. An early Holocene advance was initiated prior to 9K C14 years BP, after insolation began falling, and this advance passed the current marginal position by about 8.8-8.4K C14 years BP. The next, more-extensive advance was initiated prior to 5K C14 years BP, at a time when other paleoclimatic data indicate regional cooling and drying, emphasizing the role of summertime temperatures. The most extensive Holocene advance occurred during the Little Ice Age, consistent with the low insolation at that time.

In an abstract for a forthcoming October 2006 conference, from tree ring chronologies, they describe “warming centered on AD 950, and intervals of cooling during the Little Ice Age between the 13th and 19th centuries”.

The millennial to century-scale character of North Pacific climate is clear with cooling in the first millennium, warming centered on AD 950, and intervals of cooling during the Little Ice Age between the 13th and 19th centuries. This ring-width record is one of inferred summer temperature and is consistent with the glacial record from land-terminating glaciers for the region, which is also considered as a proxy of summer temperature.

Aside from the obvious issues, here’s what puzzles me about the sequence: when they reported the original radiocarbon dating of the logs, the most recent reported advance was ~1.6 to 1.2 Kyr BP. I’m not saying that there’s some big gotcha here; I’ve spent about 30 seconds on the topic; but I’m curious as to the non-reporting of any radiocarbon dates associated with the LIA advance.


67 Comments

  1. Deanster
    Posted Aug 24, 2006 at 7:39 AM | Permalink | Reply

    In my mind Steve, these radiodating methods regarding logs
    is valuable, but doesn’t prove that the ice had not receded to
    levels beyond those points. The Carbon Dating only refers to
    when the tree died, illustrating the first glacier advance
    over that region, but can say nothing about subsequent glacier
    advances that occurred post death of the tree.

    Afterall, once the tree is dead, it is dead. The ice can come
    and go, but the tree will remain dead.

  2. Posted Aug 24, 2006 at 7:51 AM | Permalink | Reply

    Dear Steve,

    a similar but different topic: have you read the new paper to appear in Geophysical Research Letters – your journal of choice ;-) – that argues that the oceans have cooled down significantly in 2003-2005 and undid 20% of the warming from the last half-century?

    The paper depends on evaluation of uncertainties of the counting of the heat flux – an ideal thing to be rechecked by a statistics guru. See

    http://www.pmel.noaa.gov/~lyman/Pdf/heat_2006.pdf

    If the paper is true, it more or less falsifies the treatment of ocean heat by all GCMs today, so it may be important to look.

    The paper has already been covered by some media e.g.

    http://www.dailytech.com/article.aspx?newsid=3866

    Best wishes
    Lubos

  3. jae
    Posted Aug 24, 2006 at 9:18 AM | Permalink | Reply

    #2: Maybe negative feedback, eh? Perhaps all the cyclonic activity of the past two years fed a bunch of heat to space?

  4. Steve Sadlov
    Posted Aug 24, 2006 at 9:46 AM | Permalink | Reply

    The LIA is an inconvenient truth for a certain faction.

  5. muirgeo
    Posted Aug 24, 2006 at 10:14 AM | Permalink | Reply

    Apparently it was warmer then now 10,000 and 7,000 years ago. It is now warmer then i was 5,000 years ago when ice filled the bay. Basically we need to know how the current terminus position compares to intervals between 5,000 years BP and to the time of the MWP. Is the current position more recessed then any time in the past 5,000 years?

    Might be good to write the authors for more details. However, I do not think any ambiguity exist for Thompsons recently uncovered rooted in place 5,000 year old mosses.

  6. muirgeo
    Posted Aug 24, 2006 at 10:23 AM | Permalink | Reply

    Steve,

    Re 4

    Why is the LIA inconvenient?

    Certainly it appears to be the coldest period of the Holocene. The trend during the Holocene while variable seems to be one of a generalized cooling trend suddenly interrupted by something…I suggest the industrial revolution.

    Again I would point to graph A in Fig 8 from the Thompson recent PNAS article

    The current period appears anomalous with the long term trend. Indeed maybe we did trade an impending ice box for a hot house.

  7. Steve Sadlov
    Posted Aug 24, 2006 at 10:29 AM | Permalink | Reply

    RE: #6 – Georgie, on what data do you base your “cooling through the Holocene” statement. Vostok begs to differ.

  8. Dano
    Posted Aug 24, 2006 at 12:56 PM | Permalink | Reply

    7:

    Come now, Steve. Vostok doesn’t beg. Until you audit it of course.

    [BTW, a holocene Greenland depiction has a 'tipping point' that willis and I were discussing some time ago. He may be interested to see a tipping point.]

    Best,

    D

  9. Steve Sadlov
    Posted Aug 24, 2006 at 1:05 PM | Permalink | Reply

    RE: #8 – in digital electronics that’s considered a square wave not a sawtooth. Anyhow, the whole thing is a red herring. Let’s assume that it really has been on a statistically significant cooling trend. The claim that “something has changed” is based on an upward wiggle that is considered noise on the slightly sloping downward sawtooth. Complete red herring.

  10. Dano
    Posted Aug 24, 2006 at 1:19 PM | Permalink | Reply

    9:

    Complete red herring.

    I thought the question was whether the holocene was cooling? Ah, well. Maybe it was something about the LIA…hmmm…maybe it was the anomaly…say, what was your point again?

    BTW – which journal has accepted your abstract showing nothing’s happening?

    Lemme know so I can release my breath. Maybe you should publish in Galileo…just throwin’ out the idea, Steve. I’m not going to let that ripe fruit hang out there too much longer, now…

    Best,

    D

  11. Steve Sadlov
    Posted Aug 24, 2006 at 1:25 PM | Permalink | Reply

    RE: #10 – No, it’s you who missed the point / red herring:

    “generalized cooling trend suddenly interrupted by something”

    Whether or not the Holocene is a square wave or a slightly downward sloping saw tooth is irrelevant to the fact that the “something” Georgie is trying to stir hysteria about is a mere small wiggle, not unlike all the other small wiggles superimposed onto the wave.

  12. Dano
    Posted Aug 24, 2006 at 1:42 PM | Permalink | Reply

    11:

    the “something” Georgie is trying to stir hysteria about is a mere small wiggle, not unlike all the other small wiggles superimposed onto the wave

    Which journal has accepted your manuscript showing mere small wiggle?

    Maybe you should publish in Galileo…just throwin’ out the idea, Steve. I’m not going to let that ripe fruit hang out there too much longer, now…

    Best,

    D

  13. muirgeo
    Posted Aug 24, 2006 at 1:56 PM | Permalink | Reply

    Re# 11

    The only reason it’s a small wiggle is got to do with the current rapidity of the change which is not represented in the ice core data.

    The long term trend is of general cooling, both in Vostok and Huascaràƒ⠮. Then the fact of the 5,000 year old plant suggest the uptick should be equal to at least the level it was 5,000 years ago. The uptick is also trending upwards 0.2 C/ decade…..plot that all out and the uptick is consistent with a very anomalous and rapidly changing current climate.

    Got it…Stevie?

  14. muirgeo
    Posted Aug 24, 2006 at 2:01 PM | Permalink | Reply

    Steve,

    Let’s see how you do with this one. You know that small uptick I’m all hysterical about??? Show me on either Dano’s “come” link or my “PNAS article link” where the prior most similar “uptick is.

  15. Steve Sadlov
    Posted Aug 24, 2006 at 2:02 PM | Permalink | Reply

    RE: #13 – if you were in charge of quality at any plant of reasonable output, you’d have been fired by now. Why? Because, the first time the yield fell below some idealized level “rapidly” you would have needlessly shut down the line. You would have repeated it many times. Eventually, tiring of a “boy who cried wolf” quality manager, your superiors would have given you the boot. This farcical anecdote should resonate with those who recognize the essential flaw shared by warmers and all other alarmists, in all areas where alarmism currently stirs.

  16. Steve Sadlov
    Posted Aug 24, 2006 at 2:05 PM | Permalink | Reply

    RE: #15 – 5, 6 and 7K BP are all pretty good ones. 8K BP was a bit more remarkable.

  17. Dano
    Posted Aug 24, 2006 at 2:17 PM | Permalink | Reply

    16:

    How does that track with Holocene GHG concs & incrs?

    Lemme guess: Journ Clim sent back comments. Yer gonna bust a blockbuster on us…

    Best,

    D

  18. Steve Sadlov
    Posted Aug 24, 2006 at 2:54 PM | Permalink | Reply

    RE: #17 – Quite honestly, I really don’t care at this point. Now, if it tracked for, I don’t know, maybe 1000 or so years, I might start to be impressed. Of course, there is the other big question about the phase relationship – which truly leads and which truly lags?

  19. Dano
    Posted Aug 24, 2006 at 3:14 PM | Permalink | Reply

    18:

    Quite honestly, I really don’t care at this point.

    Not very ‘scientific’.

    But you should, as the conc is unprecedented according to your Vostok, thus our wish to paint natural variance is problematic.

    Of course, there is the other big question about the phase relationship – which truly leads and which truly lags

    Well, since we are outside of the historical boundary conditions, we have a problem in determining for now, eh?

    Best,

    D

  20. jae
    Posted Aug 24, 2006 at 3:36 PM | Permalink | Reply

    17: perhaps I’m not looking at the graphs you presented properly, but it looks to me that they simply show a gradual rise of CO2 over 8,000 years. Just what are you saying, Dano?

  21. Steve Sadlov
    Posted Aug 24, 2006 at 3:42 PM | Permalink | Reply

    RE: #19 – the monkey’s on your and other warmers’ backs. You need to show the stats that say it’s unpredecented, versus what time frame, what confidence interval, etc. Ball’s in your court. Until you prove that it’s more then a bump on a gnat’s posterior, I don’t care.

  22. Steve Sadlov
    Posted Aug 24, 2006 at 3:43 PM | Permalink | Reply

    Ooops, unprecedented …

  23. Steve Sadlov
    Posted Aug 24, 2006 at 3:46 PM | Permalink | Reply

    RE: #21 – indeed, that is interesting, the 8K year view of CO2 as well as the now, very well known overlay he also linked, which is of course the basis for the ongoing discusion of whether CO2 partial pressure leads or lags temperature. I’m gonna make some popcorn! ;)

  24. Dano
    Posted Aug 24, 2006 at 3:57 PM | Permalink | Reply

    20:

    Thank you jae.

    [the graphs] simply show a gradual rise of CO2 over 8,000 years. Just what are you saying, Dano?

    The past comparisons to xYA to deem today unremarkable are flawed, as the rate of CO2 conc rise today differs than in the past. That is: eyeballing isn’t ‘scientific’.

    And the 18 If it tracked for, I don’t know, maybe 1000 or so years isn’t ‘scientific’ either, as that excludes consideration of RCCEs and their effects.

    Best,

    D

  25. Steve Sadlov
    Posted Aug 24, 2006 at 4:08 PM | Permalink | Reply

    RE: #24 – Well, Dano my man, I’ve got news for you, for all practical purposes we are still in the Quaternary. In fact, by it’s very nature, the Q is indeed known for its wild swings between ice and …. well, what we see right now … then back to ice. As you I am sure are well aware, there has been and continues to be lots of work seeking a better understanding of the boundary values that kicked off this mode we’ve been in since the onset of the Q.

  26. Dano
    Posted Aug 24, 2006 at 4:14 PM | Permalink | Reply

    21:

    You need to show the stats that say it’s unpredecented, versus what time frame, what confidence interval, etc.

    Click the links.

    Until you prove that it’s more then a bump on a gnat’s posterior, I don’t care.

    ‘Prove’ isn’t very ‘scientific’, Steve. You sound like a denialist rather than one wishing for a ‘scientific’ discussion. See, you could fire up Galileo and carve a nice niche out for yourself answering that ‘gnat’ question – esp. since a ‘gnat’ movement could affect agriculture. And if you cared, you could git you some of all that enviro grant money sloshing around out there.

    But perhaps you’re up for a policy staffer job somewhere and your non-science approach will sway one elected, not caring in the answer that way.

    Best,

    D

  27. Neil Fisher
    Posted Aug 24, 2006 at 4:27 PM | Permalink | Reply

    Re #4, you say “Again I would point to graph A in Fig 8 from the Thompson recent PNAS article

    The current period appears anomalous with the long term trend. Indeed maybe we did trade an impending ice box for a hot house. ”

    There appears to be a significantly larger anomaly 12-11k years ago. ;-)

    In any case, graphs B, D & E do not appear to show a similar anomaly so perhaps it’s the source of graph A that is anomalous? It’s the “odd man out”, is it not? For someone that suggests we should be looking at the “overall picture” and not individual proxies, it’s strange to me that you’d focus on just one graph, and one that’s so clearly anomalous compared to the others it’s presented with.

  28. Steve Sadlov
    Posted Aug 24, 2006 at 4:28 PM | Permalink | Reply

    RE: #26 – Now you’re splitting operational definition hairs. In generally accepted practice, if one can demonstrate something at some “industry standard” confidence interval (I’ve seen 95% often used), it is generally considered to be proven. Stop playing games, you know well enough the intent of what I wrote there. The burden is on the alarmists to, using again, my factory anlogy, demonstrate that over a given swath of time, the characteristics being measured are “out of spec.” If you are looking at one year, the spec limit will be very forgiving and you’d need to show are very large deviation. If you are looking at some longer time frame, obviously, the limit becomes tighter, to a point. Of course, innate variation constitutes an evental convergence and once the time frame grows sufficiently and encompasses innate variation sufficiently, a convergence limit is approached asymptotically. Again harkening to the factory, the alarmist shouts “shut down the line” in response to every minor excursion. Of course, there do need to be alarm limits, no doubt. But the stats need to define them.

  29. Dano
    Posted Aug 24, 2006 at 4:32 PM | Permalink | Reply

    25:

    Well, Dano my man, I’ve got news for you, for all practical purposes we are still in the Quaternary

    Sure.

    But technically, ‘scientifically’, you’ve forgotten that the Holocene geological epoch is within the Quaternary period. Epochs define times within geological periods and are marked by a particular, distinctive character. Subunits, if you will.

    But you haven’t been clicking my links abooo-ve to be able to grasp the distinctiooo-n.

    Best,

    D

  30. Steve Sadlov
    Posted Aug 24, 2006 at 4:59 PM | Permalink | Reply

    RE: #29 – I’ve actually read all of your stinkin’ links. It’s good that you recognize we are still in the Q. So tell me, based on that, would you or would you not expect some rapid climate transitions to be the norm?

  31. Dano
    Posted Aug 24, 2006 at 5:31 PM | Permalink | Reply

    30:

    So tell me, based on [the recognition that we are still in the Quaternary], would you or would you not expect some rapid climate transitions to be the norm?

    Well, we have to look at the Holocene, as we’re in that. So…hmmm…hmmm…looking at the Holocene…hmmm…we see that the atm CO2 ppmv conc is, today, unprecedented. So looking back is not very helpful. So I can’t give an expectation on that basis. We need something else.

    HTH,

    D

  32. jae
    Posted Aug 24, 2006 at 5:32 PM | Permalink | Reply

    26: Dano, thanks for the link. It contained the following:

    Historical records from 900 to 1300 A.D. in Europe indicate that this was a time of changes in atmospheric circulation known as the Medieval Warm Period. In high-latitude regions this was largely beneficial: grapes were grown in England and the Norse founded colonies first in Iceland and then in southern Greenland. But in arid regions a warmer climate, especially when accompanied by drought, can cause significant difficulties for farmers. A fifty-year drought occurred between 1130 and 1180 A.D. It was during this period that soil and water conservation features such as grid borders, terraces and check dams began to be built in the Four Corners area.

    Funny that Mann and the rest of the team can’t find this in the proxies. Sounds like it affected the USA (at least the West), as well as Europe. Hmmmm.

  33. jae
    Posted Aug 24, 2006 at 5:44 PM | Permalink | Reply

    Aside from the obvious issues, here’s what puzzles me about the sequence: when they reported the original radiocarbon dating of the logs, the most recent reported advance was ~1.6 to 1.2 Kyr BP.

    By jove, I think the climatologists are about to start recognizing the MWP and LIA, like the old days. Could it be that they no longer have to fear trying to publish something that does not agree with the famous hockey sticks?

  34. Dano
    Posted Aug 24, 2006 at 5:50 PM | Permalink | Reply

    32:

    Funny that Mann and the rest of the team can’t find this in the proxies [emphasis, link added]. (My 273.)

    Best,

    D

  35. jae
    Posted Aug 24, 2006 at 7:48 PM | Permalink | Reply

    Oh, Dano, here’s the one I’m used to.

  36. Dano
    Posted Aug 24, 2006 at 8:06 PM | Permalink | Reply

    36:

    here’s the one I’m used to.

    Huh.

    You get your data from a media outlet that captions the chart for a ~600 yr graph (from a first paper that didn’t look back as far as the MWP), as a thousand years, despite the x-axis being labeled to 1350?

    No doubt some here will take pleasure in reading that I’m speechless…

    Best,

    D

  37. MrPete
    Posted Aug 24, 2006 at 8:17 PM | Permalink | Reply

    Huh.

    You read your media by interpreting at less than face value, not understanding that they say “The IPCC’s version showed temperature variation over 1,000 years” (not their own), and not only that, but clicking on the chart shows the whole thing back to 1,000 years?

    Yes, no doubt some here will take pleasure in reading that you’re speechless…

    Unfortunately, you weren’t. Instead, you decided to say enough to demonstrate that even a little speech is enough to demonstrate fallibility. :-D

    Best,

    p

  38. Brooks Hurd
    Posted Aug 24, 2006 at 8:31 PM | Permalink | Reply

    Re: 36
    Dano,

    I do not know why the BBC editors chopped the graph off at 1350 for the article, but as you found out in 37, the full graph that the BBC should have used had a 1,000 year duration.

    The 2,000 year multi-proxy graphic from your link shows a MWP, but the LIA is minimized.

  39. Dano
    Posted Aug 24, 2006 at 8:34 PM | Permalink | Reply

    37:

    So you are correct. I’m fallible.

    Expanding my knowledge now. and reading the arty, I see this:

    For Professor Jones, the priority now is obtaining as much data as he can to reduce the error bars in the chart.

    He is working to obtain so-called dendroclimatic, or tree-ring, data from long-lived trees in Russia, Argentina, Chile, New Zealand, Tasmania and North America. He also wants to obtain more data from corals as well as documentary evidence from China and Japan.

    Imagine that! Someone going out and doing fieldwork. Anyone here taking notes? Anyone?

    Fieldwork!

    Hello?

    Ah, well. Let’s contrast with the next lines:

    Dr Legates says he has preliminary calculations that indicate the uncertainty in Mann and Jones’ record is probably twice as large as they indicate. [Huh. sounds familiar. what's he doing about it?]

    This, he suggests, means that recent temperature trends do not show unprecedented global warming. Professor Legates adds that he plans to work on his analysis for publication in a scientific journal.

    Alright! A forthcoming paper! It’s been two years now…lessee…lessee…humph. No paper (but look at that network analysis!).

    Disappointing, surely.

    Best,

    D

  40. jae
    Posted Aug 24, 2006 at 9:43 PM | Permalink | Reply

    dano: you are a dishonest environmental organization’s shill. period.

  41. jae
    Posted Aug 24, 2006 at 9:45 PM | Permalink | Reply

    and, oh, BTW, that was a purposful ad-hom, Dano. What a deceitful person. Hope your sponsoring organization is proud of you.

  42. Willis Eschenbach
    Posted Aug 24, 2006 at 11:30 PM | Permalink | Reply

    Re #8, Danàƒⶬ I looked at the “Abrupt” link. I noted that there were some very rapid changes in temperature, noted as an “Abrupt Climate Change”.

    I did not see:

    1) Any indication of a “tipping point”.

    2) Any source for the data.

    3) Any explanation why the colder it got, the less snowfall they say accumulated.

    I went to the rest of the site, where they feature an interactive presentation, so help me, an interactive presentation of the MBH 1998 study …

    Gosh, Danàƒⶬ I was so impressed … to quote someone I know, when is your paper on the “tipping point” going to be published?

    Truly, Danàƒⶬ saying “it’s not published” means nothing, and is getting boring. I’m considering replacing you with a Danàƒⷢot that simply repeats “it’s not published yet” … “which journal has accepted your abstract” …

    Here’s something you could do instead … think about what people write, and respond intelligently.

    w.

    PS – please don’t bother citing MBH 98 sites that contain graphs with no attribution or supporting data, it just makes you look stupider than I know you are …

  43. muirgeo
    Posted Aug 25, 2006 at 1:42 AM | Permalink | Reply

    Re #9 / 11

    So Steve you’ve given me/Dano that the long term Holocene trend has been one of generalized cooling. Now I want to address your other complaint that;

    …Georgie is trying to stir hysteria about is a mere small wiggle, not unlike all the other small wiggles superimposed onto the wave.

    First I noticed you had to use Dano’s “come” link to find any similiar uptick as noneexist in the PNAS graph. And even with this you had to go back 8,000 years to beat the current one (uptick)……isn’t my point made? Doesn’t this evidence somewhat support the spaghetti graphs/ Mann’s claim? Isn’t this growing uptick already looking pretty anomalous?

    Especially consider this uptick only has 100-200 years behind it and really has only recently, the last 50 years been coming on strong above natural variability.

    In other words…what would you expect the uptick of a very anomalous period to be when it has only just started? In fact it is very close to what has been predicted.

    You apparently want the uptick to be very obvious so you can have certainty……I on the other hand would like to avoid an obvious uptick because it’ll be happening on my grand kids time.

    Finally, look at the y-axis in Dano’s graph….1 C of variability seems to describe the whole of the Holocene…..that’s not much and that’s why they call it the Holocene. Now extend the graph out another 100 years into the future and add 2.0 C of warming (current and approximate IPPC predicted trends) to the y-axis and you’ll have your full uptick.

    And if that’s what the graph my grandkids would be plotting as the data rolls in for their time….then yeah call me hysterical because there is no way I’m gonna chance that future to them. That would be totally irresponsible.

  44. Willis Eschenbach
    Posted Aug 25, 2006 at 1:44 AM | Permalink | Reply

    Re # 6, gbalella/muirgeo, you say:

    Certainly it appears to be the coldest period of the Holocene. The trend during the Holocene while variable seems to be one of a generalized cooling trend suddenly interrupted by something…I suggest the industrial revolution.

    Again I would point to graph A in Fig 8 from the Thompson recent PNAS article

    The current period appears anomalous with the long term trend. Indeed maybe we did trade an impending ice box for a hot house.

    So, being a naturally suspicious fellow, I went to look at the PNAS article. Unfortunately, it turns out that Thompson is engaged in his usual plain and fancy footwork. The Graph A comes from Ice Core 2 in Thompsons earlier study on Huascaran. It claims that the àƒ⣃ ‹’€ ”‚¬Å¡18O changes from -19.5 to – 17.0 since the LIA.

    What’s the problem? Well, when you look at figure 3 in the Thompson paper (available at http://www.sciencemag.org/cgi/reprint/269/5220/46.pdf), it is clear that the àƒ⣃ ‹’€ ”‚¬Å¡180 average never goes much below -18 … so the big warmup is maybe half to one unit, not two units as he shows.

    His graph also places the coldest part of the LIA at the year 1400 … so if your explanation for the subsequent warming is the industrial revolution, you need to have a serious discussion with Thompson about dates.

    All in all, Thompson has put forth an effort worthy of Michael Mann.

    gbalella/muirgeo, you have this incredibly foolish habit of believing what you read. Whether or not you are a sceptic about AGW, you should definitely learn to be a sceptic about “scientific” papers …

    In any case, since we appear to be at the cold end of the Holocene, I would say that a few degrees of warming will not drive the polar bears extinct …

    w.

  45. muirgeo
    Posted Aug 25, 2006 at 1:58 AM | Permalink | Reply

    Re # 18

    Of course, there is the other big question about the phase relationship – which truly leads and which truly lags?

    Comment by Steve Sadlov

    I always like this one. Well, Steve , how about we look at the CO2 trends from our current Earth experiment to see when they started going up. Then we can compare those to contemporaneous temperature trends and we should be able to honestly see which one went first.

  46. muirgeo
    Posted Aug 25, 2006 at 2:18 AM | Permalink | Reply

    Re # 44

    …so the big warmup is maybe half to one unit, not two units as he shows.

    Willis I can’t seem to get access to the Science paper. So could you tell us what the lowest (or “warmest”) recent 18O numbers are and when was the last time they were exceeded?

  47. Willis Eschenbach
    Posted Aug 25, 2006 at 2:20 AM | Permalink | Reply

    Re 46, gbalella/muirgeo, you say:

    I always like this one. Well, Steve , how about we look at the CO2 trends from our current Earth experiment to see when they started going up. Then we can compare those to contemporaneous temperature trends and we should be able to honestly see which one went first.

    Then you reference two graphs, one that starts in the year 1000, and the other that starts in 1880, to see which one started going up first …

    Please tell me this is a joke, you can’t possibly be serious.

    In addition, Steve Sadlov was clearly talking about the initiation and termination of the ice ages, where it is quite clear, and agreed by all, that the temperature changes first, followed by the CO2 …

    w.

  48. Willis Eschenbach
    Posted Aug 25, 2006 at 2:24 AM | Permalink | Reply

    Re 17, Danàƒⶬ thank you for your link (http://www.climate.unibe.ch/clim_recon/images/indermuehle99nat_fig1.gif) showing that CO2 increased steadily throughout the Holocene.

    Of course, you also are aware that temperature dropped steadily throughout the Holocene. As gbalella/muirgeo said, “Certainly it [the LIA] appears to be the coldest period of the Holocene. The trend during the Holocene while variable seems to be one of a generalized cooling trend …”

    Perhaps you or the man with two names would care to comment on these facts, that for ten thousand years or so, the CO2 was increasing, and the globe was cooling?

    w.

  49. Posted Aug 25, 2006 at 3:34 AM | Permalink | Reply

    Re #46,

    Muirgeo (and Danàƒⶩ, the question of lead/lags in temperature/CO2 is an interesting one. In the pre-industrial period, it is quite clear that temperature leads the dance, and that CO2 follows temperature changes with some 600 years lag at the end of an ice age, and with several thousands of years at the start of a new ice age. The trend is 8-10 ppmv CO2 for each 1 C change. As there is a huge overlap (the transitions take many thousands of years), this allows climate modellers to include a huge feedback from CO2 on temperature, thus helping to increase (decrease) temperatures during transitions.

    But there is one interesting exception in the Vostok ice core: the end of the previous interglacial, the Eemian. The temperature (and CH4 – methane) levels were already near their lowest, before CO2 levels started to decline. And the result of the ~40 ppmv reduction is not measurable in the temperature record. That points to a low influence of CO2 levels on temperature. See the graphs here.

    Thus, while there is a quite good correlation between temperature and CO2 as cause and effect in the pre-industrial period (even during the Holocene: some 10 ppmv lower CO2 level during the LIA, thus caused by ~1 C difference, or 5 times more than MBH98/99 shows), it remains to be seen what the real influence of CO2 is on temperature…

  50. Steve McIntyre
    Posted Aug 25, 2006 at 4:13 AM | Permalink | Reply

    If you want to find a relevant thread to muse about CO2 lead/lag times, find it. Otherwise no more in connection with Glacier BAy.

  51. muirgeo
    Posted Aug 25, 2006 at 9:12 AM | Permalink | Reply

    Steve,

    The concern here is for inappropriate irrelevent posts…..my post have made every post on the Mann issue irrelevent and that’s what the support group is whining about.

    Willis just asked me an incredibly good question on CO2 and temperature trends through the holocene…which I’ve been waiting for….. but I guess it’s inappropriate for me to give a response? If this is the new law then fine I’ll impose my own self ban…..There is nothing more to say until the MWP forest start showing from underneath receding glaciers. If you figure out a way for trolls like me to contribute I’ll see you then. Otherwise, the support group can carry on with statistical machinations on Mann’s paper and other “relevant issues”.

    Willis….look at graph C for your answer. oops sorry..couldn’t help myself…. BYE BYE…gbalella/muirgeo troll signing off.

  52. Anonymous
    Posted Aug 25, 2006 at 10:47 AM | Permalink | Reply

    42:

    I did not see:

    1) Any indication of a “tipping point”. [you missed it.]

    2) Any source for the data. [e-m the author.]

    3) Any explanation why the colder it got, the less snowfall they say accumulated. [Basic physics. Basic stuff usu. doesn't get explained, as the reader is assumed to know the basics.]

    Truly, DanàƒÆ’à‚ⶬ saying “it’s not published” means nothing, and is getting boring. [you don't want to share your great discoveries? Odd.]

    Here’s something you could do instead … think about what people write, and respond intelligently. [Well, as Francois says, it's nuanced. The subtext is that it's great that you share your opinion, but I think it's just...oh...opinion and thank you for sharing. As for the 'intelligently', it may be embarrassing to have to explain it to you, but specifically, if you mean the Vostok topic, my thread pointed out an incorrect statement about Holocene trends, sourced the incorrect assumption for the commenter, explained scale and differences in current and past boundary conditions, clarified epochs for understanding of conditions...ohhhhh, you get the drift.

    [snip of flame]

    Best,

    D

  53. David Smith
    Posted Aug 25, 2006 at 6:20 PM | Permalink | Reply

    Interesting glacier article from the BBC. Perhaps a negative feedback mechanism?

    link

  54. David Smith
    Posted Aug 25, 2006 at 6:21 PM | Permalink | Reply

    oops, try again

    link

  55. Steve Bloom
    Posted Aug 25, 2006 at 8:22 PM | Permalink | Reply

    Re #53/4: Perhaps not, unless you want to assume that all effects of global warming should be monotonic. In any case, if you read the paper, you’ll find that the situation is more complex. Note the extensive references to a much less happy situation in the rest of the Himalayas. Things don’t look too good in the adjacent Tibetan Plateau region either. With continued warming, they may not stay that way in the Indus catchment either.

  56. JMS
    Posted Aug 25, 2006 at 8:36 PM | Permalink | Reply

    52: In case #42 needs it explained; cold air holds less water vapor than warm air. Amazingly, this can be observed perhaps in your own neighborhood. I notice that when it is really cold, we get very little snow around here (Bozeman, MT) but when the temps are in the 20′s or so we can get lots of snow. You might also look at snowfall data for the South Pole, as things have warmed, snowfall has increased…

  57. Willis Eschenbach
    Posted Aug 25, 2006 at 9:43 PM | Permalink | Reply

    Re 56 and 42, actually I asked the question to elicit the answer. I have said before that more water vapor in the air increases the albedo, by increasing both clouds and snow. However, this has been questioned. I could say all day that more evaporation => more water vapor => more snow, and Danàƒⶠwould just say “Have you published your brilliant theory yet?” …

    So, I figured I’d get him to explain it … which he did … and so did you. Thank you.

    w.

  58. Willis Eschenbach
    Posted Aug 25, 2006 at 10:57 PM | Permalink | Reply

    Re #51, gbalella/muirgeo, are you serious?

    You say:

    Willis just asked me an incredibly good question on CO2 and temperature trends through the holocene…which I’ve been waiting for….. but I guess it’s inappropriate for me to give a response? If this is the new law then fine I’ll impose my own self ban…..There is nothing more to say until the MWP forest start showing from underneath receding glaciers. If you figure out a way for trolls like me to contribute I’ll see you then. Otherwise, the support group can carry on with statistical machinations on Mann’s paper and other “relevant issues”.

    Willis….look at graph C for your answer. oops sorry..couldn’t help myself…. BYE BYE…gbalella/muirgeo troll signing off.

    When I went to your reference, I saw the graph of decreasing insolation in the northern hemisphere over the Holocene … It looked too smooth to be real, so I went to the underlying document and found that it’s the change due to the Milankovich astronomical cycle …

    Are you really sure, muirgeo/gbalella, you want to claim that the holocene cooled because of the Milankovich cycle? Dude, Thompson has suckered you …

    You see, because the change shown in his neat little graph is precession driven, the SH insolation increased as much as the NH decreased during that time, and he’s talking about the SH, Quelccaya and Kilimanjaro.

    Thompson claims that “The general shape of the 18O profile from both HuascaràƒÆ’à‚⠮ and Kilimanjaro is consistent with the Holocene tropical insolation curve between latitude 0° and 30°N (Fig. 8C), suggesting that the warmer temperatures of the early Holocene were largely insolation-driven in response to the Earth’s precession.”

    Ooooh, that’s real scientific. The general shape of two curves, one of which is a sine curve, “is consistent”. This “suggests” that the sine curve is the cause of the other curve … suggests? The general shape suggests? I thought this was science, but no, no r^2, no measures of correlation, he’s just finding out who is suggestible …

    However, somehow he doesn’t remind the audience that both Kilimanjaro and HuascaràƒÆ’à‚⠮ are in the Southern Hemisphere … or that there was no net global precession driven change in insolation during that time …

    So let me ask my question again. For thousands of years, the CO2 rose during the Holocene while the temperature fell … why?

    w.

  59. JMS
    Posted Aug 25, 2006 at 10:58 PM | Permalink | Reply

    Water vapor doesn’t increase albedo, clouds increase albedo. [stop flaming please]

  60. Willis Eschenbach
    Posted Aug 25, 2006 at 11:10 PM | Permalink | Reply

    JMS, if you think the idea that clouds increase albedo is a “brilliant theory”, you haven’t been following the plot …

    w.

  61. Steve Bloom
    Posted Aug 26, 2006 at 1:56 AM | Permalink | Reply

    Re #56/7: Things appear to be more complicated. Among other things, it is not snowing more in Antarctica even though it should be. See the current post at RC for some interesting details.

    Also, strictly technically the business about warmer air holding more water vapor is an example of Bad Meteorology (although the distinction has no consequences for this particular application).

  62. Tom Brogle
    Posted Aug 26, 2006 at 2:37 AM | Permalink | Reply

    I read the article cited by Steve Bloom.
    It is just scientific rubbish.

  63. Sam
    Posted Aug 27, 2006 at 5:58 PM | Permalink | Reply

    I find the comments regarding Glacier Bay very interesting since I will be going there next week. I recently watched a documentary regarding the area on cable and found it gratifying that the lady National Park Ranger who was discussing the history of the bay very matter of factly stated that within 300-400 years the entire area would probably be completely iced-under again. Apparently, the people who live and work in the area don’t by into the idiocy of the Warmers. Please disregard the trolls who torment this site (Dano, Bloom, Mureigo or alter ego or whatever.. they are just playing tag team and trying to stir up the natives. Dano frequents many sites to do just this and should not be given the time of day) No ad hom intended, just the observation of experience.

  64. Steve McIntyre
    Posted Aug 27, 2006 at 7:42 PM | Permalink | Reply

    #63. It may be a little outside the scope of local guides, but I’m puzzled as to why the original radiocarbon dates cited above didn’t have anything mentioned from the LIA moraine. Maybe you could get some information from the original authors as to where the samples dated to 1.6-1.2 kyr BP were taken on the ground; then compare that location to where the LIA moraine is. It would be worthwhile asking them for a sample location map – they sound like geologists and, unlike dendro people, might have one.

  65. Mark T
    Posted Aug 27, 2006 at 10:11 PM | Permalink | Reply

    Off topic, but I just need to mention in this thread that there is a bay/creek/some body of water in Alaska that shares my last name. I do not know how it got there.

    Mark

  66. Paul Gosling
    Posted Sep 4, 2006 at 6:24 AM | Permalink | Reply

    Steve

    To answer your original question (speculate at least). If the glaciers had already reached the sea before the LIA advance there would be no trees to overide and provide evidence.

    Paul

  67. Steve McIntyre
    Posted Sep 4, 2006 at 7:38 AM | Permalink | Reply

    I wonder where the trees in Wiles’ tree ring chornology are located then. It’s too bad that tree ringers don’t provide (more) maps.

Post a Comment

Required fields are marked *

*
*

Follow

Get every new post delivered to your Inbox.

Join 3,115 other followers

%d bloggers like this: