Allen and the "Cool" Medieval Pacific

A press release for Allen (Current Anthropology 2006) has been referred to as showing that there was a “cool” medieval Pacific – thus supporting the view of the Team that the MWP was an incoherent dog’s breakfast. I was wondering if an anthropology professor had actually generated new paleoclimate records – it seemed unlikely, but who am I to throw stones? In this case, it turned out that it was just a review article and the only salient proxy was Kim Cobb’s Palmyra Island corals, which I will add to my evidence list.

As an anthropologist, Allen argued that recent paleoclimate research had overturned “traditional” climate views held by New Zealand anthropologists – relying on concepts like the Little Ice Age and Medieval Warm Period:

For the past 50-odd years, Pacific archaeologists, geographers, and other social scientists have been using a model of Late Holocene climate change based largely on climate variability known from other regions of the world (e.g., Fagan 2000; Grove 1988; Lamb 1965)… In the central Pacific, both observational studies and climate modelling now suggest that the MWP was relatively cool and the LIA relatively warm, the inverse of Northern Hemisphere conditions.

In recent years, the geographer Patrick Nunn (1991, 1998, 1999, 2000a, 2003; Nunn and Britton 2001) has drawn on a wide range of paleoclimate proxies in an effort to refine ideas about Late Holocene climate in the Pacific and evaluate its effects on the region’s human populations. Evidence from the continental margins has been particularly important in this effort, augmented by oxygen isotope analysis of a New Zealand stalagmite (after Wilson, Hendy, and Reynolds 1979) and Nunn’s own sealevel studies from Pacific island localities (1998, 2000b), data he has used as proxy indicators of temperature change. Nile River flow data (from Anderson 1992), which suggest changes in El Ninàƒ’€¹à…’€œo–Southern Oscillation (ENSO) frequency around AD 1300, have also been incorporated into Nunn’s climatic framework. Drawing on these varied records, Nunn (2000a, 716) has identified the MWP as a warm, dry period (relative to today) with persistent trades, extending from about AD 750 to 1250, and the LIA as a cool, dry period with increased storminess between AD 1350 and 1850. Nunn (2000a; Nunn and Britton 2001) has also been particularly interested in the MWP/LIA transition. He suggests that initially there was a significant but short-lived increase in precipitation, followed by an abrupt shift to the cooler conditions of the LIA. Specifically, he argues that this transition was so rapid (less than a century) that it precipitated a series of environmental and social “catastrophes.” He links an array of geomorphic and biotic changes to this “AD 1300 event” (Nunn 1999, 2000a) and suggests that it led to significant disruptions in human settlement, subsistence, and voyaging, as well as increases in competition and warfare, throughout the Pacific, including parts of Micronesia and the Hawaiian Islands.

Allen stated that new data overturned this climate model:

These new data suggest that the model of Late Holocene climate change initially developed in New Zealand, based on Northern Hemisphere patterns, extended to the Pacific islands by Nunn (1991, 1999, 2000a, 2003; Nunn and Britton 2001), and used in the past by a large number of Pacific scholars (myself included), is inappropriate for the central Pacific.

Nearly all the data cited by Allen was coral data, which, other than the Cobb data, was not proposed to go back to the MWP.

Most important among these are those from long-lived corals, which are allowing for sometimes continuous and generally high-resolution (often monthly) reconstructions (e.g., Cobb et al. 2003a; Hendy et al. 2002; Linsley,Wellington, and Schrag 2000; McCulloch et al. 1996; Tudhope et al. 2001; Urban, Cole, and Overpeck 2000; Woodroffe, Beech, and Gagan 2003).

The main series of interest to here are shown in the figure below – Cobb’s data at the left.


Original Caption: Figure 2. Summary of proxy records relevant to Pacific climate in the Late Holocene. Palmyra coral O: record of monthly resolved coral 18 d O (thin black horizontal lines) shown with ten-year running average 18 d (thick white horizontal lines) relative to the average of the Palmyra modern coral O for the period AD 1886 to 1975 (grey vertical line) from Cobb 18d et al. (2003a, fig. 5). The dating error for all five coral sequences is  yrs. or less. Radiative forcing: data from Mann et al. (2005, fig. 1a), 10 shown as . Great Barrier Reef, Rarotonga coral Sr/Ca: reconstruc- 2 W/m tions of sea surface temperature anomalies based on coral Sr/Ca records from Hendy et al. (2002, fig. 2) and Linsley, Wellington, and Schrag (2000). Hendy et al. resampled the records to equivalent five-year averages and normalized the series to the common period of AD 1860 to 1985. New Caledonia coral O: reconstruction of interannual (thin black hor- 18d izontal line) and interdecadal (thick white horizontal line) coral Orecord 18d from Ame´de´e Lighthouse from Corre`ge et al. (2001, 3478, fig. 2). Laguna Pallcacocha ENSO record: reconstruction of number of ENSO events in 100-year nonoverlapping windows, based on data from Moy et al. (2000b).

She notes that Hendy et al interepreted dO18 as a measure of salintiy, but preferred Cobb’s interpretation as temperature:

For example, Hendy et al. (2002, 151), comparing of O, Sr/Ca, and in 18Od strumental sea surface temperature from multiple sites, argue that the O signal in the southwestern Pacific is sea-surface- 18O d salinity-dominated. Others (e.g., Cobb et al. 2003a; Kilbourne et al. 2004) have found the reverse, highlighting both the possibility of regional variation in the strength of sea-surfacetemperature–O relations (see above references for discussions of potential confounding factors) …

As can be seen from the above figure, the Cobb coral data is the only one that purports to go back to the MWP and it is not continuous. I’ll discuss it separately but the two early values are based on single corals, each of which is dated by U/Th ratios (in the presence of high natural Th background values). Allen:

Among the more lengthy Late Holocene Pacific climate reconstructions is one from Palmyra in the equatorial Line Islands. Here monthly-resolved records of 30- to 150-year intervals are available for a period of 1,100 years (Cobb et al. 2003a, 2003b). Although this study relies on O alone, the 18 d authors demonstrate strong correlations with the regional twentieth-century instrument records. Within this 1,100-year period, five time intervals were examined (fig. 2), three represented by multiple overlapping fossil coral records which were spliced together, a procedure that increases the number of independent observations of a climatic state at a given time interval. measuring both trace elements and O. 18 d …

Most important among these is the coral O record from 18 d Palmyra, which covers several time intervals over the past millennium. As do paleoclimate reconstructions from the Northern Hemisphere, where the warmest and coldest decades over the past millennium differ by less than 1.0 deg C (Jones and Mann 2003, 20), the Palmyra record suggests relatively modest temperature fluctuations, with average temperature varying by no more than 0.6 deg C, if O values are scaled to 18 d temperature alone (Cobb et al. 2003a, 274). However, two time intervals stand out in the Palmyra case, the tenth century AD, which was the coolest and/or driest period, and the late twentieth century, the warmest and wettest period (fig. 2).The cold interval, centred on the early tenth century (AD928–61), appears to have been of some amplitude and its onset relatively abrupt. Below-average temperatures (relative to the period AD 1886–1975) are also apparent in the midtwelfth-to early-thirteenth-century window (AD 1149–1220). In contrast, during the seventeenth century (AD 1635–1703) temperatures on Palmyra were comparatively warmer, more like those of the recent past.Because other tropical Pacific records of similar temporal duration were lacking, Cobb et al. (2003a) compared their findings with a multiproxy reconstruction from the Northern Hemisphere (Mann, Bradley, and Hughes 1999), with unexpected results. Surprisingly, the coolest and/or driest period on Palmyra coincides with the Northern Hemisphere MWP, while the height of the LIA (the seventeenth century) is registered in the Palmyra corals as a comparatively warm period, particularly in relation to temperatures observed in the tenth and to a lesser extent the twelfth century.

Further, if twentieth-century sea-surface temperature–rainfall relationships held through the past millennium, then we might infer that the MWP in the central Pacific was comparatively dry while the LIA was relatively wet, a proposition that is also supported by the foregoing reconstructions.The Palmyra corals indicate that during the seventeenth century, the coldest period of the LIA elsewhere in the world (see Jones, Osborn, and Briffa 2001, 664; Fagan 2000), ENSO activity was more intense in this equatorial setting than at any other time period represented by these corals (Cobb et al. 2003a, 275) (but see below). Not only is there a significant increase in the number of El Ninàƒ’€¹à…’€œo events but event amplitude is marked, with some rivalling the “Giant El Nino” of 1997–98, one the largest events of this century

So the only actual proxy data set that needs to be evaluated is Kim Cobb’s corals.


56 Comments

  1. Posted Aug 5, 2006 at 4:38 PM | Permalink

    The figure appears to be missing for me.

    You know, this whole issue of “I think x is a proxy for y” has to stop. The scientists who disagree should present their competing theories for what the proxy represents until one of them is falsified. Until then it just sounds like they’re cherry-picking to me. Did the author of this study explain WHY the dO18 should be a proxy for temperature and not salinity, or just assert it?

  2. muirgeo
    Posted Aug 5, 2006 at 4:41 PM | Permalink

    Yes the figure is missing for me too.

    Anyway looking at this one southern hemisphere stalagmite it does appear that the year 1000 was not much different then the present days warmth and that the warming in the Southern hemisphere was delayed compared with the north. I wonder if this ties in with the “See-Saw” climate theory?

  3. jae
    Posted Aug 5, 2006 at 5:42 PM | Permalink

    muirgeo: ?? It looks to me like the figure you linked shows that the MWP had a much higher temperature than the present.

  4. bender
    Posted Aug 5, 2006 at 5:55 PM | Permalink

    Re #1: If you think “this whole issue of “I think x is a proxy for y” has to stop”, you might want to think again. Even if you were to pull all funding from all paleocliamtologists, they would still do what they do, assuming the things they like to assume. The problem is not the fuzziness of the science; it’s the failure to appreciate and accept that fuzziness, and to communicate it accurately to policy people.

    Re #2: Me too.

    Re #3: Note: the series stops in the 1950s or 1960s.

  5. Gerald Machnee
    Posted Aug 5, 2006 at 6:01 PM | Permalink

    The figure is missing when I go thru Firefox, but I get it with Google.

  6. muirgeo
    Posted Aug 5, 2006 at 6:03 PM | Permalink

    Re # 3

    Isn’t the northern MWP more centered around 1000 to 1100. …” According to our reconstruction, high temperatures”¢’‚¬?similar to those observed in the twentieth century before 1990″¢’‚¬?occurred around AD 1000 to 1100″ Moberg. Where as this southern hemisphere plot is centered more around 1200 to 1400. Looks somewhat asynchronous to me.

  7. Posted Aug 5, 2006 at 6:06 PM | Permalink

    bender : I guess my point is, this study seems to be based on “unsettled science”. What I mean by that is, scientist A thinks this is a proxy for X, scientist B thinks this is a proxy for Y. Surely the best thing to do is to get scientists A and B to discuss it and try to work out whether it’s X, Y or something else. Until then, wouldn’t it be best to avoid these types of proxies? Why spend time analyzing them (GIGO) when you could instead be studying the proxies themselves in an attempt to ascertain just what they mean?

    I agree, if you’re going to report results based on uncertainties anyway, it’s important to characterise just what the uncertainties are.

    Weird, I can see the figure if I pull its URL out of the page source and go there. I am also using Firefox… the IMG tag looks OK to me so I don’t know how to account for that.

  8. Steve Bloom
    Posted Aug 5, 2006 at 6:06 PM | Permalink

    Steve M., some months back I linked to a California Current foraminifer study that showed things as fairly flat there through the MWP and LIA. This was in the context of discussions of local climate in the southern Sierras.

    Let’s also not forget the Antarctic ice core CO2 study from a few weeks ago, which showed pretty flat results based on a *global* metric. Why so little discussion of that?

  9. Steve McIntyre
    Posted Aug 5, 2006 at 6:08 PM | Permalink

    #7. I just transferred the image about 30 seconds ago, so it was probably between cache views.

  10. Steve McIntyre
    Posted Aug 5, 2006 at 6:12 PM | Permalink

    #8. Steve B, as you know, I’ve been occupied with some other presentations plus I miss some things. I presume that the article in question is Field et al 2006, which I also got today at the library., and will discuss. It’s amazing in it – even though people have supposedly “known” about supposedly lower MWP temperatures for some time, it seems that the majority of evidence being presented has been identified in the past 5 minutes so to speak – and that the older evidence is all flawed. I wonder if a year from now, it will be the same.

  11. jae
    Posted Aug 5, 2006 at 6:18 PM | Permalink

    Steve B.: Idso lists dozens of papers that suggest a strong MWP and LIA. Since you support “consensus” positions, it looks to me like “the science is settled” here.

  12. Peter Hartley
    Posted Aug 5, 2006 at 6:52 PM | Permalink

    Re #8: Steve Bloom has been pushing the Caluifornia foraminifera study for some time. A little googling reveals that the species concerned are phytoplankton known to be sensitive to CO2 fertilization. Maybe these are the “bistlecones of the sea” so to speak. Their recent productiivty reflects CO2 increases directly rather than temperature, making earlier, smaller, increases look indicative of smaller temperature departures. per5haps this is wht the Hockey team means by “moving on” to new studies. We just keep picking new plant species that are sensitive to CO2 fertilization and hope it takes time for the auditors to catch up, at which point we will have moved on to the next example.

  13. Steve Sadlov
    Posted Aug 5, 2006 at 7:03 PM | Permalink

    RE: #12 – Also, I can’t imagine that the California Current would have been much warmer than now even during the MWP, nor, much colder, during the LIA. So, forminifera in this area of the world are probably reacting to something besides temperature in their growth and dearth.

  14. Deanster
    Posted Aug 5, 2006 at 7:11 PM | Permalink

    Isn’t that a funny thing. A cool pacific. Last I checked, the pacific is still relatively cool. Seems I saw a color temp depiction on NASA of GISS that showed that pretty much all the warming is in the Atlantic and Europe, and sections of Northern N. America.

    Maybe this whole concept of “global warming” is the wrong approach …. maybe we should be looking specifically at regional sites.

  15. Steve Bloom
    Posted Aug 5, 2006 at 7:59 PM | Permalink

    Re #10: Steve M., given the inherent difficulties of this field of study, I’m confident you’d be able to spend the rest of your life on it. I’m just not sure why you’d want to. In any case, yes, Field was the one. (BTW, a month or two ago I recall seeing an article on a new large-scale California coast coring expedition that was just completed, so apparently considerable new results can be expected within the next year or so.)

    My POV on all of this is that there is a vast amount to be learned from studies of paleoclimate. I suspect most of the researchers in the field consider the global AGW aspect to be somewhat off-point, mainly because it involves stitching together bunches of regional proxies to try to draw global conclusions of limited relevance to anything. (It’s the regional results themselves that have the relevance, although that sid doing the global stuff is probably fun and increases the chances of getting into the marquee journals.) Truly global proxies such as the recent CO2 results may help draw firmer conclusions about the average of past globally averaged climate, but such results will still have limited value because it will probably be possible to accurately quantify all past forcings.

    MBH98 and the other early hockey stick studies had value in answering the question of whether past climate was wildly different from today’s such that scientists would have to re-think their understanding of the basic mechanisms of climate. It was never terribly important to the science whether the MWP was cooler, the same or warmer than today’s climate. Public relations was a different story, which is why the IPCC honchos saw that nice flat shaft and got a little carried away. (There was also a “See, look what we know about climate!” aspect.) Fortunately all of this is very nearly history. At some point even the WSJ editorial pages and Fox News will abandon the cause, although some version of this site will doubtless carry on.

    Re #12: A link or two (preferably to your search page so other can see what you saw) would be appreciated when you make claims of that sort. I try to do the same.

    Re #11: jae, the idsos list lots of things. Their tactic of intentionally misinterpreting legitimate papers is widely known.

  16. jae
    Posted Aug 5, 2006 at 8:44 PM | Permalink

    SBloom:

    Re #11: jae, the idsos list lots of things. Their tactic of intentionally misinterpreting legitimate papers is widely known.

    Mr. Bloom, I am still waiting for some kind of proof for this statement. You and your employer (i.e., the Sierra Club) just WISH this were true. Goddam it, prove it, Steve. Give me an equal number of references to show otherwise, and i will join the Sierra Club!

  17. Gary
    Posted Aug 5, 2006 at 8:54 PM | Permalink

    FWIW, Hodell, et al. have looked at climatic influence on Mayan culture and have generated high resolution dO18 curves. Might this be another set of proxy records from another region to for investigation of the MWP?

    Solar Forcing of Drought Frequency in the Maya Lowlands
    David A. Hodell,1* Mark Brenner,1 Jason H. Curtis,1 Thomas Guilderson2

    We analyzed lake-sediment cores from the Yucatan Peninsula, Mexico, to reconstruct the climate history of the region over the past 2600 years. Time series analysis of sediment proxies, which are sensitive to the changing ratio of evaporation to precipitation (oxygen isotopes and gypsum precipitation), reveal a recurrent pattern of drought with a dominant periodicity of 208 years. This cycle is similar to the documented 206-year period in records of cosmogenic nuclide production (carbon-14 and beryllium-10) that is thought to reflect variations in solar activity. We conclude that a significant component of century-scale variability in Yucatan droughts is explained by solar forcing. Furthermore, some of the maxima in the 208-year drought cycle correspond with discontinuities in Maya cultural evolution, suggesting that the Maya were affected by these bicentennial oscillations in precipitation.

  18. Gerald Machnee
    Posted Aug 5, 2006 at 9:08 PM | Permalink

    Re #10 and #15 – Are you referring to the following?–
    **Field, C.V., G.A. Schmidt, D. Koch, and C. Salyk 2006. Modeling production and climate-related impacts on 10Be concentration in ice cores. J. Geophys. Res., in press.**
    I do not see what is –**Truly global proxies such as the recent CO2 results**– (global) about this study.
    This paper has a lot of *simulated, possible, implies, modelling, roughly, estimate, suggest*.
    In other words, it has yet to be audited.

  19. Gerald Machnee
    Posted Aug 5, 2006 at 9:13 PM | Permalink

    Re # 15 – **It was never terribly important to the science whether the MWP was cooler, the same or warmer than today’s climate.**
    Really??? Steve B. Is that what they say at RC?
    So is this the new cartoon?

  20. Ian Castles
    Posted Aug 5, 2006 at 9:30 PM | Permalink

    So it was “never terribly important to the science whether the MWP was cooler, the same or warmer than today’s climate”, Steve Bloom?
    But “public relations was a different story” and “the IPCC honchos saw that nice flat shaft and got a little carried away”?

    Well, the honchos at the American Geophysical Union had already been carried away when they issued a news release headed “1998 was warmest year of millennium, climate researchers report” on 3 March 1999, twelve days before the publication of the “report” by Mann, Bradley and Hughes in their journal.

    Obviously the statement was acceptable to, if not drafted by, the three researchers: in fact, it was published in virtually identical terms by the University of Massachusetts at Amherst and the University of Arizona.

    According to the news release, the two MBH studies had “determined that human-induced greenhouse gases were a major factor in 20th century global warming.” The 1000-year reconstruction had “revealed” that “temperatures dropped an average of 0.02 degrees Celsius per century prior to the 20th century.”

    The statement also quoted Michael Mann as saying that the findings of the study were “startling revelations”. The researchers had found that “Temperatures in the latter 20th century have been exceptionally warm compared to the preceding 900 years”; and that “The slow, moderate, long term cooling trend that we found makes the abrupt warming of the late 20th century even more dramatic. The cooling trend of over 900 years was dramatically reversed in less than a century. The abruptness of the recent warming is key, and it is a potential source for concern.”

    The news release reported Raymond Bradley as saying that “Temperatures in the latter half of the 20th century were unprecedented”, and Malcolm Hughes as saying that “even the warmer intervals in the reconstruction pale in comparison with mid-to-late 20-century temperatures.”

    Notes at the foot of the news release invited journalists to contact any of the three authors, and provided their phone numbers and email addresses. They also provided links to an on-line press kit (including photos of the researchers, graphics and a link to the “report”) and “Frequently Asked Questions”.

    Of course Michael Mann himself could be characterised as an “IPCC honcho”. He’d been named as a lead author for the TAR some months earlier.

  21. Pat Frank
    Posted Aug 5, 2006 at 9:56 PM | Permalink

    #15 — From Steve Bloom: “Their [the Idsos'] tactic of intentionally misinterpreting legitimate papers is widely known.”

    Ah, delusion! Ah, irony! One laughs. :-D

  22. bruce
    Posted Aug 5, 2006 at 10:01 PM | Permalink

    Re: #15: Onya Steve B! Love your work!!

  23. Pat Frank
    Posted Aug 5, 2006 at 10:03 PM | Permalink

    #20 — Ian, you should write an article outlining the political history of the MBH98,99 construction. It appears the attack lies, ah, falsifications, oops, can’t write that, knowing misrepresentations, wait: unproven, ineptnesses ummm, errors are now being covered by retreat lies (no overstatement there).

  24. Dave Dardinger
    Posted Aug 5, 2006 at 10:19 PM | Permalink

    re: Idsos,

    Actually I’m sure there are some researchers who don’t like the conclusions the Idsos reached by reading their papers. This is because said researchers either were convinced of AGW and didn’t like careful scrutiny reversing what they concluded from their research or they didn’t want their peers getting the idea that they themselves were skeptics, lest they be blackballed, and therefore felt the need to distance themselves from what the Idsos concluded. But the real test is to see what the paper says and what the Idsos say and deciding whether the conclusion is “plausable” to use a term we all recognize.

    So, SB, find a paper which we can link to on-line, and which the authors of which claim that the Idso’s mischaracterized their work, and let’s have a little fun.

  25. MarkR
    Posted Aug 5, 2006 at 10:23 PM | Permalink

    I can understand how people from countries with shorter histories could easily be mislead about the MWP, the LIA, and the Dark Ages etc.

    I find it inexcusable that the British scientists involved could be so ignorant of their own history.

  26. muirgeo
    Posted Aug 6, 2006 at 12:55 AM | Permalink

    Re # 15

    It was never terribly important to the science whether the MWP was cooler, the same or warmer than today’s climate.

    Got that right. There is one absolute that makes the current period different from all the rest of the Holocene and even the preceding 500,000 years…and that’s the current levels of CO2 in the atmosphere.

    I understand that for some reason the skeptics want to believe this 400,000 year old
    correlation is suddenly going to part because it’s now politically incorrect but I suspect nature doesn’t care about their politics.

    In fact, if the Holocene climate variability is found to be greater then the current evidence suggest the biggest concern is that it might simply imply a higher degree of climate sensitivity and an actual under-estimate of anthropogenic warming in the current model projections.

    Shoot it’s hard being a climate change skeptic….one line of argument after another is blown out of the water. First the UHI effect argument gets flamed, next the MSU satellite data goes down…so might as well attack the proxies data since the argument at least sounds like it might be of significance….then that goes down and your left with attacking the motives of the messengers and all sort of grand conspiratorial huey involving Nature, Science, the NAS and the glaciers….plus you wouldn’t want to play the…”oh we can adapt card too soon”…

  27. ET SidViscous
    Posted Aug 6, 2006 at 1:04 AM | Permalink

    I can assumne from you posting that link that you agree with two things that graph shows.

    1. Dramatic temprature increases absent Anthrpegenic causes.

    2. Earths past climate has been warmer than current

    Shoot it’s hard being a climate change gearmongerer. You have to keep blowing your own lines of argument one after another, out of the water.

  28. muirgeo
    Posted Aug 6, 2006 at 1:44 AM | Permalink

    Re # 28

    Absolutely right Sid. I’d agree with one and two. But those facts are about as signifcant to us as the climate on Pluto because we never have been exposed to them as the modern civilization on the brink that we now are.

  29. bruce
    Posted Aug 6, 2006 at 2:07 AM | Permalink

    Re: #15 and #27: Oh, George and Steve B, while you are looking for that paper addressing the Idso’s “transgressions”, perhaps you might think about an answer to that question posed on another thread re how the marked up/edited version of the Summary for Policymakers of the TAR is so VERY different from the science contained in the body of the IPCC report. It almost seemed that someone with a political agenda decided that the message of science wasn’t strong enough to achieve certain goals, so they misrepresented, exaggerated and falsified the conclusions of science. It must have been embarrassing that that marked up version of the Summary for Policymakers got out, Eh!

    I sure hope that we won’t see such an egregious example of politicisation this time around.

  30. John A
    Posted Aug 6, 2006 at 3:28 AM | Permalink

    I’m still waiting for Steve Bloom to explain who the “error-prone amateurs” are.

  31. nanny_govt_sucks
    Posted Aug 6, 2006 at 4:02 AM | Permalink

    I’m still waiting for Steve Bloom to explain how North American aerosols cause cooling while Chinese aerosols cause warming.

  32. muirgeo
    Posted Aug 6, 2006 at 4:16 AM | Permalink

    Re # 30

    It almost seemed that someone with a political agenda decided that the message of science wasn’t strong enough to achieve certain goals, so they misrepresented, exaggerated and falsified the conclusions of science.

    Comment by bruce

    Yeah, those darnd oilmen.

  33. MrPete
    Posted Aug 6, 2006 at 4:19 AM | Permalink

    #29

    Absolutely right Sid. I’d agree with one and two. But those facts are about as signifcant to us as the climate on Pluto because we never have been exposed to them as the modern civilization on the brink that we now are.

    Amazing!

    muirgeo, you are *this* close to understanding the benefit of Steve M’s work.

    The next logical steps are quite simple:

    a) Climate has been this warm before, sans anthropogenic causes
    b) We have zero validated evidence of anthropogenic causes today
    c) In fact, we are clueless enough that we even have some evidence that “fixes” may well make things worse.

    Given all this, does it really behoove us to raise an immediate red flag about AGW?

    Wouldn’t it make more sense to
    d) Discover, if possible, what is really going on
    e) Discover, if possible, if there is actually anything we can do about it
    f) Discover if proposed “solutions” will help, harm or accomplish nothing?

    blessings,
    p

  34. bruce
    Posted Aug 6, 2006 at 4:20 AM | Permalink

    Re #33: You have to be winding me up George. In the words of Pauline Hanson (a name familar to Australians) Please Explain!

  35. charles
    Posted Aug 6, 2006 at 4:27 AM | Permalink

    #27 muirgeo

    Again, since warming is ~ log co2 there is no reason to believe the next 100 yrs will see more warming than the last 100. And the modest warming of the last 100 (due to co2 or not)has been a net plus.

    If you doubt modest warming is a net plus first get a mental image of the tropics. Now get a mental image of the artic.

  36. Peter Hearnden
    Posted Aug 6, 2006 at 4:34 AM | Permalink

    Re #34

    b) We have zero validated evidence of anthropogenic causes today

    Blimey.

    Even Steve and John A think there will be some AGW. If you think there is no evidence of said then what kind of gas is CO2 (or for that matter various CFC’s, CH4, O3)?

  37. muirgeo
    Posted Aug 6, 2006 at 5:01 AM | Permalink

    Re # 35

    HEY LOOK!!! They got their OWN hockey stick. Any questions?

  38. KevinUK
    Posted Aug 6, 2006 at 5:09 AM | Permalink

    muirgeo,

    Was this hockey stick generated using non-centred PCA using Fortran 77 code that someone has intellectual property rights to and so can therefore not be published so that it can be inependently reviewed?

    KevinUK

  39. muirgeo
    Posted Aug 6, 2006 at 5:11 AM | Permalink

    Re# 36

    Again, since warming is ~ log co2 there is no reason to believe the next 100 yrs will see more warming than the last 100. And the modest warming of the last 100 (due to co2 or not)has been a net plus.

    OH LOOK! An advanced definitive GCM all in TWO sentences. Ewe wait….you left out water vapor and albedo changes…..oh and you didn’t caluculate in the heat of melting ice and warming bodies of water…Other then that….oh and melting bogs and permafrost…any way good job….maybe you should inform NASA of your 2 sentence GCM model. I’m sure they’ll be impressed.

  40. Kevin
    Posted Aug 6, 2006 at 7:23 AM | Permalink

    Just curious how much accurate data we really have on CO2 and other GHG concentrations. The Mauna Loa CO2 data only go back as far as 1955, for example.

  41. John A
    Posted Aug 6, 2006 at 7:45 AM | Permalink

    Even Steve and John A think there will be some AGW. If you think there is no evidence of said then what kind of gas is CO2 (or for that matter various CFC’s, CH4, O3)

    There is some AGW, the questions are whether its significant, whether its harmful, whether its worth trying to restrain it or just adapt to it. You focus fixedly on CO2 as a greenhouse gas and refuse ever to discuss why in ice cores, CO2 is always a response to previous climatic warming and never a precursor. The fact that temperatures and CO2 are both currently rising is a correlation and not a causation.

    If temperatures go down again (as they did c.1940 – 1976) then I predict that the focus will be on smokestacks and forest burning (with appropriate videos for each) masking the “greenhouse warming”. Whichever way the climate goes it will be blamed on mankind, with natural variation written out of the script. AGW is unfalsifiable.

  42. welikerocks
    Posted Aug 6, 2006 at 8:40 AM | Permalink

    #39 ” Ewe wait….you left out water vapor”
    Ewe wait? Is that how sheeple talk to each other in private?
    #37 Yes, I have a question. Who is they ?

  43. welikerocks
    Posted Aug 6, 2006 at 8:50 AM | Permalink

    And re: #42 and #37, you might want to keep this in mind muirgeo before you continue with your mind spew or tell me who “they” is:

    Canada remained the largest exporter of total petroleum products in May, exporting 2.313 million barrels per day to the United States. The second largest exporter of total petroleum products was Mexico (1.710 million barrels per day) which had a slight decrease from last month of 0.040 million barrels per day.

    Or read the whole thing here:

    http://tinyurl.com/7ldt

  44. muirgeo
    Posted Aug 6, 2006 at 8:51 AM | Permalink

    Re # 42

    They are guys like this.

  45. welikerocks
    Posted Aug 6, 2006 at 9:17 AM | Permalink

    #44
    You might want to update your data here:

    http://tinyurl.com/1zsk

    At least have accurate data on “people like that” if you are going to be a bigot.

  46. Steve McIntyre
    Posted Aug 6, 2006 at 9:50 AM | Permalink

    #43-46. Stop this ad hom stuff. If you want to talk science, fine. I personally think that reducing oil consumption is a good thing, but this has nothing to do with interpreting whether the proxy data shows evidence of a cool medieval Pacific.

  47. welikerocks
    Posted Aug 6, 2006 at 10:13 AM | Permalink

    Steve, apologies. I think that reducing oil comsumption is a good thing as well. I’d be happy if you deleted all of our exchange.

    On topic: husband says corals maybe a great proxy for indicating climate changes regionally, and a cool medieval Pacific isn’t proof of anything just more pieces of the puzzle that is our earth.

    Here’s a abstract about salamanders and MWP:

    http://tinyurl.com/h45bo

    Results

    We found a significant difference in body size index between paedomorphic and metamorphic individuals during the time interval dominated by the Medieval Warm Period. There is a consistent ratio of paedomorphic to metamorphic specimens through the entire 3000 years, demonstrating that not all life history characteristics of the population were significantly altered by changes in climate on this timescale.

    (Of course they site the IPCC in the first paragraph of the paper as reference forr what’s happening now.)

  48. jae
    Posted Aug 6, 2006 at 10:50 AM | Permalink

    First the UHI effect argument gets flamed, next the MSU satellite data goes down…so might as well attack the proxies data since the argument at least sounds like it might be of significance….

    Another statement without any documentation. Prove it, George.

  49. ET SidViscous
    Posted Aug 6, 2006 at 11:33 AM | Permalink

    “Absolutely right Sid. I’d agree with one and two. But those facts are about as signifcant to us as the climate on Pluto because we never have been exposed to them as the modern civilization on the brink that we now are. ”

    Yeah but the graph is nicely cyclical, Which means that we will, regardless of AGW, so we might as well get used to it.

    And if we are within that range, which you have already agreed to, and that range has been proven to be natural, as you have done, and Anthropogenic influences of ~ 1 degree, are nothing to get into a huff about. It’s arguable that civilization has had to deal with it before or not (MWP) but if as we see nature can vary this much (over 13 degrees by that graph), any playing we do in the noise is no big deal. Global temperatures increasing by less then a degree is barely even noticeable, much less of concern.

    But your exaggerating a bit when you say “as significant to us as the climate on Pluto” Because we are not far removed from those global averages (~1degree) in the ice cores, while we are significantly removed from Pluto’s clime (greater than 200 degrees) and in fact, those cores show a global average, our summer temperatures are far in excess of those averages in the ice cores and somehow mankind has survived. With a little help from Ice tea, beer, and the evil AC. So we have been there before.

  50. welikerocks
    Posted Aug 6, 2006 at 11:44 AM | Permalink

    Correction for my #47
    My husband didn’t say corals were pretty good proxy for regional temperature but for sea level proxy! Sorry, I got it totally wrong and misunderstood him! Ad hom induced brain fart!

    He says he’s never heard of corals for temp proxy until now. All the papers he’s read, professors his known and worked with, lectures attended, etc on corals is that they give pretty good data for sea level. He’s gonna read this paper though and maybe comment.

  51. charles
    Posted Aug 6, 2006 at 7:45 PM | Permalink

    #39 muirgeo

    you say

    “Ewe wait….you left out water vapor and albedo changes…..oh and you didn’t caluculate in the heat of melting ice and warming bodies of water…Other then that….oh and melting bogs and permafrost”

    If these effects are material in the future then they have been material in the past. They didn’t spring to life just because someone decided to build a computer model.

    The effect of CO2 on warming (what ever it is) will be less in the future than it has been in the past since co2 is increasing linearly and warming due to co2 is ~log co2.

  52. Steve Sadlov
    Posted Aug 7, 2006 at 9:45 AM | Permalink

    RE: #16 – if you join it, then by golly, I may have to do the unthinkable, and consider rejoining it! LOL! :-) (Crunchy con through and through … )

  53. Steve Sadlov
    Posted Aug 7, 2006 at 10:01 AM | Permalink

    RE: 326 – UHI is a misnomer. Anthropogenic thermal dissipation and land modification are niether limited to connurbations nor do they result in any sort of well defined and delimited “islands.” There is only an “island” if one artificially washes out all the overall variations in ATD and leaves the urban areas to be seen against an artificial “mean.” IR images from orbit tell the true story. There is an areal distribution of ATD (and land use mods) that map roughly to human population density, moreso in industrialized countries less so elsewhere. Over time this last issue will become less pronounced.

  54. charles
    Posted Aug 7, 2006 at 6:42 PM | Permalink

    #39 muirgeo

    The small and shrinking influence of CO2.

    Combine co2 warming ~ log co2 with the assertion below. Barking up the wrong tree are we? Remember, half of 20th century warming occured before 1950 and the big rise in co2. What ever warming has occured co2 seems to have been a minor contributor in the past and with the log relationship is poised to play an even smaller role in the future.

    Now consider the beneficial fertilization aspects of increased co2 ……

    “Based on information that indicated a solar activity-induced increase in radiative forcing of 1.3 Wm-2 over the 20th century (by way of cosmic-ray flux reduction), plus the work of others that indicated a globally-averaged solar luminosity increase of approximately 0.4 Wm-2 over the same period, Shaviv calculated an overall and ultimately solar activity-induced warming of 0.47C (1.7 Wm-2 x 0.28C per Wm-2) over the 20th century.

    Added to the 0.14C of anthropogenic-induced warming, the calculated total warming of the 20th century thus came to 0.61C, which was noted by Shaviv to be very close to the 0.57C temperature increase that was said by the IPCC to have been observed over the past century.

    Consequently, both Shaviv’s and Idso’s analyses, which mesh well with real-world data of both the recent and distant past, suggest that only 15-20% (0.10C/0.57C) of the observed warming of the 20th-century can be attributed to the concomitant rise in the air’s CO2 content.”
    –CO2 Science Magazine, 19 July 2006

  55. charles
    Posted Aug 7, 2006 at 8:39 PM | Permalink

    I too would not be willing to bet against warming but I would take the bet based on net damage from increased co2. The fertilization value of increased co2 and the net value of very modest co2 induced warming make it a safe bet.

    “Based on information that indicated a solar activity-induced increase in radiative forcing of 1.3 Wm-2 over the 20th century (by way of cosmic-ray flux reduction), plus the work of others that indicated a globally-averaged solar luminosity increase of approximately 0.4 Wm-2 over the same period, Shaviv calculated an overall and ultimately solar activity-induced warming of 0.47C (1.7 Wm-2 x 0.28C per Wm-2) over the 20th century.

    Added to the 0.14C of anthropogenic-induced warming, the calculated total warming of the 20th century thus came to 0.61C, which was noted by Shaviv to be very close to the 0.57C temperature increase that was said by the IPCC to have been observed over the past century.

    Consequently, both Shaviv’s and Idso’s analyses, which mesh well with real-world data of both the recent and distant past, suggest that only 15-20% (0.10C/0.57C) of the observed warming of the 20th-century can be attributed to the concomitant rise in the air’s CO2 content.”
    –CO2 Science Magazine, 19 July 2006

  56. MrPete
    Posted Aug 8, 2006 at 10:23 PM | Permalink

    LOL… #37 — you’ve pulled your own version of MBH98!

    So we have had relatively smooth oil prices, with a recent hockey stick?

    You forgot to check historical data…
    Click here, in IE only (Sorry, the graphic I found is an IE-only picture.)

    Most of those here were alive for the 1970’s oil shortages which had a rather severe effect on prices. And, provably, oil cost more than today in inflation-adjusted terms.

    Misuse of stats is certainly not limited to climate ;)

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