National Post Today

Aug 23, 2006 – 10:01 AM

We have an op ed in the National Post today about the Wegman Report. In addition, Terence Corcoran has a long article about a recent hatchet job published by the Globe and Mail about Tim Ball from a writer named Charles Montgomery. I had to laugh out loud at the following comments by Corcoran about Montgomery:

Touring for his latest book, The Shark God, about life on islands in the South Pacific, Mr. Montgomery asks the big science questions: "Can a man convince a shark to eat his enemies?" He says he found himself believing in "the strangest things: rainmaking stones, magic walking sticks."

I guess Mann’s temperature reconstruction might be another "magic stick"? Continue reading →

By Stephen McIntyre | Posted in NAS Panel, News and Commentary | Comments (349)

Laguna Paco Cocha, Peru

Aug 22, 2006 – 8:40 PM

A while ago, I summarized an interesting article from the Venezuelan Andes. In that case, they concluded that the glaciers did not exist in the MWP. The post is worth re-reading in the context of Quelccaya. The authors used the continuous deposition of sediments in a proglacial lake to yield evidence of the discontinuous movements of the glacier.

Given that Thompson’s PNAS article is so inadequate as a survey of relevant information, one can only wish that a similar study had been done at one of the Quelccaya proglacial lakes. If one had, you’d think that even Thompson would have thought to mention or that one of the PNAS referees would have asked about it.

But, hey, it’s Thompson so you never know what fundamental information he leaves out. I googled Paco Cocha, the name of one of the proglacial lakes and, needless to say, there was an almost precisely identical study to the one in the Venezuelan Andes, Abbott et al 2003 . It was even done by geologists at Ohio State – Thompson’s own university. You’d think that Thompson would give them a mercy citation – but this is the Team.

Abbott et al concluded that "glaciers were probably absent from the watershed between 10.0 and 4.8 thousand years BP – which raises interesting questions about the 50,000 year old moss. The authors conclude that glaciation has been present in the area since 4800 BP. but with "significant fluctuations."

Multiproxy analyses of Laguna Paco Cocha (13″‚⟵4S, 71″‚⟵2W) include studies of sedimentology, geochemistry, physical properties, magnetic susceptibility, and stable isotopes. The age model for the core was produced by linear interpolation between 11 calibrated AMS radiocarbon dates on individual macrofossils (Table 1) (Stuiver et al., 1998). Fig. 4 shows the results from the analysis of organic matter content (LOI at 500″‚⠃), bulk density, magnetic susceptibility, cellulose-inferred N18Olw, and mass accumulation rates of organic and mineral matter. The abrupt shift to glacial values at 4.8 ka B.P. for all parameters is highlighted by a dashed black line.

This includes decreased organic matter values from ~15 to 65 wt%, higher dry bulk density from 60.5 g/cc to ~0.9 g/cc, higher magnetic susceptibility from 65 to ~10 SI, and an abrupt N18Olw decrease of 3x. We interpret the results of the analyses presented in Fig. 4 to show that glaciers in the Paco Cocha watershed retreated rapidly beginning prior to ~12.7 ka B.P. and were gone from the watershed by 10.0 ka B.P., as indicated by the dashed gray line (Mark et al., 1999). Although glaciers were probably absent from the watershed between 10.0 and 4.8 ka B.P., the lake remained at the overflowing stage during this period, as suggested by analyses of organic matter, sediment density, and magnetic susceptibility. If the lake had desiccated during this period we would expect oxidation of organic matter leading to low values which we do not see. Additionally, cellulose-inferred N18Olw values remained 6310x suggesting that the lake did not become a closed basin during this period. Increased mineral and decreased organic matter accumulation rates after 4.8 ka B.P. also support the return of glacial ice to the watershed at this time and the lack of ice in the drainage basin during the early and middle Holocene. After glaciers returned to the watershed at 4.8 ka B.P. they have been present until today, but analyses of organic matter, sediment density, and magnetic susceptibility in addition to changing accumulation rates suggest significant fluctuations during this period. Cores from Laguna Llacho Kkota, which is located to the south (15″‚⟰7S, 69″‚⟰8W), show the onset of wetter conditions at 3.4 ka B.P.


Fig. 4. Sediment-core analyses from Laguna Paco Cocha including organic matter, dry bulk density, magnetic susceptibility, cellulose-inferred N18Olw (thick line is the three-point running average), and mass accumulation rates of organic and mineral matter. The dashed horizontal gray line indicates the retreat of glaciers to at least the neoglacial limit by 10.0 ka B.P., and the horizontal dashed black line shows the return of glaciers to the watershed at 4.8 ka B.P. The vertical dashed lines on the graph of inferred N18Olw provide a framework to interpret the status of the watershed based on the modern calibration samples shown in Fig. 3. The cellulose-inferred N18Olw values were corrected for a systematic o¡set arising from methodological di¡erences between the University of Waterloo and University of Minnesota laboratories (Beuning et al., 2002).

Reference: Abbott et al 2003, Holocene paleohydrology and glacial history of the central Andes using multiproxy lake sediment studies, Palaeogeography, Palaeoclimatology, Palaeoecology 194 (2003) 123-138. url

By Stephen McIntyre | Posted in Proxies, Thompson | Tagged , , | Comments (53)

No Andean Glaciers from 19 to 27S

Aug 22, 2006 – 10:36 AM

Before Caspar Ammann started playing for the Team, he was a geologist who wrote the following serviceable discussion of glaciation in the “dry” Andes between 19 and 27S (Quelccaya is at 12S).

Under current climatic conditions, no glaciers can exist in the high Andes of the Western Cordillera in the high Andes of the Western Cordillera between 19 and 27 S. The annual mean temperatures in the highest peaks are far below freezing but the extremely dry conditions make any glacial development impossible. With increasing summer precipitation towards the tropics, persistent snowfields are more frequent and at 18 30’S the first glacier appears (Volcano Guallatiri) In the southern region, first glaciers appear under sharply increased wintertime precipitaiton south of 27S. Between these two regimes, the South American Dry Diagonal crosses the Andes from the northwest to the southeast.

What does that mean for glaciation at Quelccaya? It might not mean anything. But it’s interesting that the glaciers in the region are on a macro scale precipitation-limited.

When I see a rather good geologically-based article by Ammann, it’s too bad to see him writing such statistical bilge with his co-author Rev. Wahl. He should have stuck to being a geologist.

Now that I think about it, for all the criticism from the Team about me being an “amateur”, neither Ammann nor Wahl is a statistical specialist. Ammann studied as a geologist and Wahl took economics and theology cv here. He has some theological material on the internet.

Reference:
Ammann et al 2001, PPP 172, 313-326 http://www.glaciologia.cl/textos/amman.pdf

By Stephen McIntyre | Posted in Proxies, Thompson | Comments (32)

Quelccaya Plant Deposits Again

Aug 21, 2006 – 3:49 PM

James Lane here noticed a couple of other useful references on Quelccaya and related the anecdotal information to this information. He observed:

It took me ages to put this post together, juggling between different sites. I don’t think one can conclude anything from the information, as presented, except that the moss has grown at higher altitudes in the past than now.

His location is a substantial improvement over what I’d posted up before, about which Lee complained. I’ll take another crack at collating the information in light of James’ additional thoughts on the matter. Continue reading →

By Stephen McIntyre | Posted in Proxies, Thompson | Tagged | Comments (100)

USCCSP: Temperature Trends in the Lower Atmosphere

Aug 18, 2006 – 12:31 PM

One of the Kevins has drawn Appendix A “Statistical Issues Regarding Trends” in the recent USCCSP report "Temperature Trends in the Lower Atmosphere" to my attention. The appendix is coauthored by the omnipresent Wigley. Continue reading →

By Stephen McIntyre | Posted in News and Commentary, Statistics | Comments (457)

Attention fFreddy

Aug 16, 2006 – 1:53 PM

The nearly useful "Recent Comments List" plug-in has been upgraded.

It now works correctly. If the any string of letters (such as a URL) is more than ten fifteen characters long then it replaces the long character string with "…" which should stop the moaning from the IE6 users.

fFreddy: I owe you a pint.

By John A | Posted in General | Comments (17)

Plant Deposits at Quelccaya

Aug 15, 2006 – 6:02 PM

Thompson et al (PNAS 2006) stated that the discovery of a plant deposit with radiocarbon age of around 4000 BP (calibrated to 5138 BP) near the receding margin of the Quelccaya glacier provided “strong evidence” that the “current retreat of Quelccaya is unprecedented for the last 5 millennia”. The plant deposit is Distichia muscoides, which is a component of Andean peat deposits whose present limit is 400-500 m lower than the discovery.

In order to better understand the significance of this discovery, it would be nice to have information of the stratigraphy of the discovery as glacial deposits in other localities which have been mapped in detail, often have extremely complicated histories with re-working of deposits.

Of course, it’s Thompson, so we get a pamphlet, rather than a geologic report. However, with a bit of googling, I identified the following other recent discoveries of plant deposits from receding margins of Quelccaya glacier: The plant deposit reported in the PNAS article appears to date from Thompson’s 2002 expedition (url), but other plant deposits cited in news releases were not reported in the PNAS article.

  • Mark et al 2002 reported the discovery of peat dated to 2700 BP at the receding margin of the glacier ice cap. Their Table 1 indicates that the discovery was in a 1977 expedition.
  • in the 2003 campaign, a plant deposit was discovered dated to 2200 years BP
  • also in the 2004 campaign, a deposit of moss was identified at the maximum radiocarbon date of 50,000 years – from which Thompson speculates that the moss may date to the Eemian period 110,000 years ago
  • in the 2005 campaign, more plant deposits were discovered with dates varying from 4500 to 6500 BP.

Continue reading →

By Stephen McIntyre | Posted in Proxies, Thompson | Tagged , | Comments (228)

Rejected Nature Correspondence

Aug 15, 2006 – 6:11 AM

Last week, Mann et al published a letter in the Nature Correspondence section saying that it was "hard to imagine how much more explicit" they could have been about the uncertainties and blaming "poor communication by others" for the "subsequent confusion", disucssed here. The Mann et al letter is absurd and Ross and I decided to submit a short reply to Nature Correspondence, shown below together with Nature’s rejection.

The Steve and Ross Letter

Sir:
In their recent correspondence, (Nature, 442, 627, 2006) Mann et al. claim that "it is hard to imagine how much more explicit we could have been about the uncertainties in the reconstruction" (Nature, 392, 779-787, 1998). In fact, it is not hard at all. They could have disclosed and explicitly discussed the lack of statistical significance of the verification r2 statistic for reconstruction steps prior to 1750, values of which were approximately 0 (S. McIntyre and R.McKitrick, GRL, 32, doi:10.1029/2004GL0217502005, 2005; E. Wahl and C. Ammann, Clim. Chg, accepted, 2006). Such disclosure would have shown that the uncertainties of their reconstruction were substantially underestimated, as the National Academy of Sciences panel recently concluded (p. 107).

Mann et al blame "poor communication by others" for "subsequent confusion about uncertainties", but ignore the fact that Mann was a lead author of chapter 2 of the IPCC Third Assessment Report, which stated that the Mann et al. reconstruction had "significant skill in independent cross-validation tests," without mentioning the verification statistic failures. They likewise ignore their own press releases, issued by the University of Massachusetts, and contemporary press articles linked at Mann’s website, which set the overconfident tone they now apparently regret. There is no evidence that Mann et al made any effort to correct these "poor communications" either at the time or subsequently.

Nature itself must share blame for the length of time it took to identify these statistical failures. In 2003, after Mann et al had refused to provide to us either the test scores, residual series or even the results of the individual steps for independent statistical verification, we filed a Materials Complaint with Nature requesting this data. Nature refused to intervene, saying that disclosure was up to the original authors. Perhaps this experience will encourage Nature to re-consider such policies.
Stephen McIntyre and Ross McKitrick

Within a few days, we received the following rejection letter from Maxine Clark, Publishing Executive Editor:

Thank you for your Correspondence submission, which I regret we cannot offer to publish. The paragraph about "poor communication" does not add substantially to our news report, to which Mann et al. were responding in their letter. Nature has no connection to the press releases you describe. Perhaps you would prefer to communicate directly with Mann et al. on your opinion on these matters, as you letter has more of a tone of a complaint about the authors than of something that Nature readers would find of interest?

Your last paragraph is confusing to us because Nature has already published a correction to this paper containing Supplementary Data, as part of the complaint you initiated. This has closed the matter so far as we are concerned.

Yours sincerely

Maxine Clarke

I suppose that I should have known that it was foolish to expect Nature to give a vestige of equal treatment when it came to climate science. But you keep hoping. I went the following reply:

Your publication of the letter by Mann et al and rejection of our letter leaves a very uneven record of this particular controversy, which has attracted considerable attention even since the National Academy of Sciences panel report, including a further report criticizing Mann et al by senior statisticans (Wegman et al.) and two hearings by the U.S. House Energy and Commerce Committee. The response by Mann et al to your news report contained an absurd characterization of the quality of their original disclosure. That you rejected a rebuttal to this absurd characterization does not add to Nature’s credibility in this matter.

Your characterization of the situation in respect to Supplementary Data is also completely inaccurate. The Supplementary Information to the Mann et al Corrigendum did not contain results for the individual steps, that I had originally requested in 2003. On Aug 10, 2004, I re-iterated the request for this information with Karl Ziemelis, who took it up with the Editor. In Sept 2004, Nature refused to provide the information in the following terms: "And with regard to the additional experimental results that you request, our view is that this too goes beyond an obligation on the part of the authors". While the publication of the July 2004 Corrigendum may have "closed the matter as far as you are concerned", please do not confuse this with actually providing this particular and essential data, which remains undisclosed to this day.

Update (later that day): I received the following reply from Maxine Clark of Nature:

Thanks for your message. These issues are not appropriate for publication in Correspondence. From what you say below, and from looking into this matter myself before writing to you earlier, your previous complaint has been dealt with, even though you were not satisfied by the outcome. If you feel there is more to be said about that, please take the matter up with the editors who were handing your complaint.

Our News story reported the criticisms of Mann et al. Nature readers are well aware, via this and previous articles, that this is a controversial topic. Your letter serves mainly to express your negative opinion of these authors and also concerns a technical interpretation of the data or availability of the data. There are channels for you to take up these matters, but Correspondence is not appropriate, nor is the type of language you use in your letter about these authors and about Nature in general appropriate for publication. Incidentally, I don’t appreciate the tone of the comments you make to me personally, either, which are uncalled-for.

Yours sincerely

Maxine Clarke
NATURE

Update – May 3, 2007
On August 23, 2007, we re-submitted our comment so that the language tracked the MBH language as closely as possible. The MBH letter accepted for publication read as follows:

Your News story “Academy affirms hockey-stick graph”‘? (Nature 441, 1032; 2006) states that the US National Academy of Sciences (NAS) panel “concluded that systematic uncertainties in climate records from before 1600 were not communicated as clearly as they could have been”. This conclusion is not stated in the NAS report itself, but formed part of the remarks made by Gerald North, the NAS committee chair, at the press conference announcing the report.

The name of our paper is “Northern Hemisphere temperatures during the past millennium: inferences, uncertainties, and limitations” (Geophys. Res. Lett. 26, 759-762; 1999). In the abstract, we state: “We focus not just on the reconstructions, but on the uncertainties therein, and important caveats” and note that “expanded uncertainties prevent decisive conclusions for the period prior to AD 1400”. We conclude by stating: “more widespread high-resolution data are needed before more confident conclusions can be reached.” It is hard to imagine how much more explicit we could have been about the uncertainties in the reconstruction; indeed, that was the point of the article!

The subsequent confusion about uncertainties was the result of poor communication by others, who used our temperature reconstruction without the reservations that we had stated clearly.

Our revised letter read as follows:

Your News story “Academy affirms hockey-stick graph” (Nature 441, 1032; 2006) states that the US National Academy of Sciences (NAS) panel “more-or-less endorses the work behind the [Mann et al hockey stick] graph”. This conclusion was not stated in the NAS report itself nor by any of the panellists at the NAS panel press conference releasing the report.

Many specific findings of the NAS report contradict the claim in your story. For example, the NAS panel report stated that the Mann et al decentered principal components methodology should not be used; that temperature reconstructions should avoid the use of strip-bark bristlecones and foxtail proxies, that the Mann et al reconstruction was strongly dependent on these problematic proxies; that their reconstruction failed important verification tests; and that they had incorrectly estimated uncertainties in their reconstruction.

At the press conference, panel chairman North said that he agreed with the “substance” of the Mann et al reconstruction. However, this language is nowhere used in the report itself, where the panel expressly referred to the reconstruction merely as “plausible” and specifically withheld any attribution of confidence intervals for the period before 1600.

Jayne Hill wrote in early September declined publication stating:

Thank you for your Correspondence submission, which we regret we are unable to publish. Our news story was indeed citing North’s comments at the press conference, which as they say “substantially” support Mann et al., and which is clear from the text of the news story.

Thank you again for writing to us.

Notice the asymmetry in reasoning. MBH were allowed to comment on observations made by North on the basis that they were inconsistent with the NAS Report, but we weren’t.

By Stephen McIntyre | Posted in NAS Panel | Tagged , | Comments (136)

Some Geologists at Quelccaya

Aug 14, 2006 – 4:27 PM

Just when I’d despaired of ever seeing anything as mundane as a site map of the Quelccaya glacier on a scale that did not also show all of South America, I stumbled (due to the wonders of google) on an interesting article by Mark et al (2002), a geologist from Ohio State – the same university as Lonnie Thompson – on glacial moraines in the Quelccaya area. Of course neither the NAS panel nor Thompson deign to cite an article as mundane as one by a geologist. It was nice to read an article that focussed on the presentation of facts without moralizing all the time.

I’ve mentioned that I’d like to see other stratigraphic and contextual information relative to the report of the 5000-year old Distachia reported in a recent pamphlet by Thompson – that it was published in PNAS does not elevate Thompson et al 2006 from being IMHO a "pamphlet". In any event, I’ve teased out some information including this from Mark eet al 2002:

Other peat exposed at the modern ice margin [from their Table 1, this appears to have been collected in 1977] dates to 2760 cal yr B.P., implying that the Quelccaya Ice Cap at that time was smaller than present and may have disappeared completely during the middle Holocene. Two ice cores drilled 154.8 and 163.6 m to bedrock through the ice cap contain records that are only 1350 and 1500 years old (Thompson et al., 1985).

Continue reading →

By Stephen McIntyre | Posted in Proxies, Thompson | Tagged | Comments (54)

The Coming Katrina Anniversary

Aug 14, 2006 – 1:17 PM

In a few days, we will reach the anniversary of the formation of Hurricane Katrina in the middle Atlantic (Aug 18, 2005). By this time last year, we’d had 4 hurricanes, including two category 4/5 hurricanes, with Katrina about to hit. The final 2005 tally was 28 named storms, 15 hurricanes, 7 "major" (Category 3 -111 mph – or higher) hurricanes and 4 Category 5 hurricanes.

Predictions in May 2006 were for 8-10 hurricanes (4-6 Cat 3+). So far this year we’ve had 3 "named storms" and the Atlantic is quiet as of today. A "named storm" has a minimum wind speed of 40 mph, so one may presume that comparative early 20th century statistics for "named storms" are unlikely to be comprehensive. On Aug 6, 2006, predictions were revised slightly down to 7-9 hurricanes (3-4 Cat 3+).

Named Storms Hurricanes Cat 3+ Hurricanes
2005 Season 28 13 7
May 22, 2006 Forecast 13-16 8-10 4-6
Aug 6, 2006 Forecast 12-15 7-9 3-4

What are the chances of this happening? Let’s compare the post-Aug 14 period for 2005 against the predictions for the balance of the season. After a very busy start to the 2005 season, there were 11 hurricanes and 5 Cat 3+ hurricanes from this point on in 2005. Despite a relatively quiet start to 2006, the current predictions are for only a very slight reduction in post-Aug 14 hurricanes – from 11 last year to 7-9 this year and only 1-2 less major hurricanes than last year.

Named Storms Hurricanes Cat 3+ Hurricanes
Balance 2005 20 11 5
Aug 6, 2006 Forecast 9-12 7-9 3-4

What do I know about hurricanes? Hardly anything. But I’d sure be inclined to bet that the number of hurricanes in a season has something to do with persistence and that early vortices in the Atlantic breed later vortices somehow. Based on the quiet Atlantic so far this year, I’d bet on the under (let’s say 7 or fewer hurricanes; 8 a wash).

By Stephen McIntyre | Posted in General | Comments (243)