Read on for a new Josh cartoon.
What’s wrong with this image? Well if you are part of The Team (RealClimate and friends), it goes against everything you’ve been publishing. You want the Medieval Warm Period to disappear, and you want a hockey stick at the end showing “unprcedented” warming. The shape below just doesn’t cut it when that’s what you are researching selling.
On the left is temperature in °C, on the X axis, years, with labels from 0AD to the year 2000.
Images like the above don’t sell. With a clear MWP and no hockey stick, there’s no alarm, and no $$ coming in for “further studies”. In the Wake of the Gergis et al retraction, Steve McIntyre notes that one of the “screened out” datasets just happens to be the one with the best resolution and the greatest duration – the Law Dome Oxygen 18 data set (from Antarctica). He writes:
An annual version for two millennia was provided to Gergis (who screened it out.) delD and O18 are closely related and presumably the unarchived del D series will look somewhat similar.
For those that don’t know what this data represents, here’s a quick primer from Wikipedia.
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Oxygen isotope ratio cycles are cyclical variations in the ratio of the abundance of oxygen with an atomic mass of 18 to the abundance of oxygen with an atomic mass of 16 present in some substances, such as polar ice or calcite in ocean core samples. The ratio is linked to water temperature of ancient oceans, which in turn reflects ancient climates. Cycles in the ratio mirror climate changes in geologic history.
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Connection between temperature and climate
The 18O/16O ratio provides a record of ancient water temperature. Water 10 to 15 °C (18 to 27 °F) cooler than present represents glaciation. As colder temperatures spread toward the equator, water vapor rich in 18O preferentially rains out at lower latitudes. The remaining water vapor that condenses over higher latitudes is subsequently rich in 16O.[2] Precipitation and therefore glacial ice contain water with a low 18O content. Since large amounts of 16O water are being stored as glacial ice, the 18O content of oceanic water is high. Water up to 5 °C (9 °F) warmer than today represents an interglacial, when the 18O content of oceanic water is lower. A plot of ancient water temperature over time indicates that climate has varied cyclically, with large cycles and harmonics, or smaller cycles, superimposed on the large ones. This technique has been especially valuable for identifying glacial maxima and minima in the Pleistocene.
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McIntyre adds:
Oxygen isotope series are the backbone of deep-time paleoclimate. The canonical 800,000 year comparison of CO2 and temperature uses O18 values from Vostok, Antarctica to estimate temperature. In deep time, O18 values are a real success story: they clearly show changes from the LGM to the Holocene that cohere with glacial moraines.
On its face, Law Dome, which was screened out by Gergis and Karoly, is an extraordinarily important Holocene site as it is, to my knowledge, the highest-accumulation Holocene site yet known, with accumulation almost 10 times greater than the canonical Vostok site. (Accumulation is directly related to resolution: high accumulation enables high resolution.) The graphic below compares glacier thickness for some prominent sites for three periods: 1500-2000, 1000-1500 and 0-1000. its resolution in the past two millennia is nearly double the resolution of the Greenland GRIP and NGRIP sites that have been the topic of intensive study and publication.
Given the high reliance on O18 series in deep time, one would think that paleoclimatologists would be extremely interested in a publication of the Law Dome O18 data and be pressuring Tas van Ommen on this point.
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But despite the apparent opportunity offered by Law Dome, there has been virtually no technical publication of a high-resolution O18 or delD isotope series.
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A Climategate email shows that Phil Jones asked about the omission of the Law Dome series from the IPCC illustration in the AR4 First Draft. I asked the same question about the AR4 Second Draft. They realized that the Law Dome graphic had an elevated medieval period and thus, including it in the graphic would – to borrow a phrase from the preparation of AR3 – would “dilute the message” and perhaps provide “fodder to skeptics”.
Read the whole report at Climate Audit here
The Team keeps trying to bury this stuff, and Climate Audit keeps digging it up:
Nick, look at the scale on the X-axis.
Ah Ha, Nick turns the graph upside down with: “Not so clear to me. As I recall, d18O correlates negatively with temperature.” We just knew it w/could happen.
Nick, you need to read the entire post again. It certainly is not a negative correlation.
Nick Stokes says:
“With a clear MWP
Not so clear to me. As I recall, d18O correlates negatively with temperature.”
Indeed it does – that’s exactly the point. Colder temperatures cause O18 to precipitate closer to the equator with less making it to higher latitudes. Warmer temperatures allow more O18 to diffuse to higher latitudes. The MWP is clearly shown on the graph from approximately year 650 through 1150. The LIA is not so clear, but still present.
Clean your glasses, read the articles carefully, then support your snark with real science, (oh, but first, open your mind).
In all scientific curiosity, I truly want to hear the honest explanation from someone on the Team or their fan club why they exclude this data. We speculate conspiracy, but is there some scientific justification for exclusion? In Big Pharma you cannot exclude any data. If you collect it, you have to make it available. No excuses.
“not so clear to me. As I recall, d18O correlates negatively with temperature.”
Nick, take a closer look at the graph. The
Y- coordinates decrease as you move vertically up the graph. Did you borrow Mike Mann’s Tiljander colored glasses before doing your analysis?
Sorry, I meant look at the scale on the Y-axis.
Hey, I just got things back to front. Does this qualify me for a place on the Team and a big grant ?
@John Barrett
The MWP is not long enough. My contention is that the LIA that started around 1300-ish was a catastrophic drop in temperatures from a previously very high point.
According to HH Lamb the LIA started later in the SH, with Antarctic sea ice not a maximum till as late as 1900.
pwl asks who Law was. Phillip Law was an Australian scientist who worked in Antarctica for many years between about 1950 and 1965.He added a great deal to early post-war Antarctic science and exploration.
@ur momisugly andrewmharding “I think in years to come, the hockey stick will rank equally with epicycles as far as science by bigotry goes.”
I would respectfully disagree and suggest that you are being a bit unfair to the idea of epicycles. When the theory of epicycles was proposed it was really the best explanation of what was being observed. Granted, after the data became more clear with longer and more accurate observations, the idea of epicycles became more and more complicated until it was finally replaced by heliocentrism, but it seems that at a minimum we can grant that the people who supported epicycles were honest in their support. CAGW, in contrast, is perhaps more akin to the Piltdown Man story. As we see in CAGW theory a longer and longer trail of unexplained and unethical alteration of data, misrepresentation of the facts, and unscientific refusal to allow for discourse and debate, one can only come to the conclusion that — just as with Pildown Man — we are not witnessing honest error, but rather conscious fraud.
Louis Hooffstetter says: June 13, 2012 at 4:04 am
“Clean your glasses, read the articles carefully, then support your snark with real science, (oh, but first, open your mind).”
No snark. It’s a question of how d18O varies with T. I simply said that n my understanding of that relation it didn’t seem that way to me. And got a bewildering array of responses.
The graph isn’t in Celsius, it’s in d18O ratio units. And the scale isn’t inverted, as a lot of people said. What I was probably wrong about, as I promptly noted, is that the interpretation of d18O vs temp scaling can vary. In coral etc it’s negative, which would make the logic here wrong. But in ice cores, it’s apparently generally positive.
OK, sorry for raising the question. But it seems I’m not the only one confused.
“With a clear MWP “
Not so clear to me. As I recall, d18O correlates negatively with temperature.
I wondered the same thing, noting that the d18O graph of the Pleistocene warmer temperatures were increasingly negative, while in Law Dome they are the opposite.
However, after hearing dozens of different commenters telling “Nick Stokes” he is an idiot with conflicting reasons why, I still don’t have a clear explanation.
Am I imagining things, or are Google searches becoming more ‘fair and balanced’? I googled ‘law dome’ (without the quotes) and was shocked to see several links back to climateaudit.org in the top half of the first page.
Or perhaps the Google folks just haven’t adjusted this query to push the usual AGW/CAGW sites into the front of the response queue.
Here’s my original query, in case the weights get adjusted as we speak:
https://www.google.com/#hl=en&output=search&sclient=psy-ab&q=law+dome&oq=law+dome&aq=f&aqi=p-p1g3&aql=&gs_l=hp.3..35i39j0l3.10869.12897.0.13117.8.7.0.1.1.0.304.1057.0j6j0j1.7.0…0.0.pWUmh3VDzDs&pbx=1&bav=on.2,or.r_gc.r_pw.r_cp.r_qf.,cf.osb&fp=e4ffb39c8a89267f&biw=1008&bih=622
😐
Roy says (June 13, 2012 at 1:59 am):
You are doing Ptolemy a great disservice.
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Absolutely. And it cost the taxpayers nothing for 1500 years despite being wrong.
PS: Has anyone pointed out to Nick Stokes……oh wait. 🙂
Ignore Antarctica folks, the Medieval Warm Period was a kinda patchy, northern hemisphere affair (except for South America, New Zealand, South Africa, Australia and of course the hot house Antarctic Peninsula).
Lots of peer reviewed evidence that the MWP was global phenomenon.
http://www.co2science.org/data/mwp/mwpp.php
Gary,
Right above the graph, it says in English:
“On the left is temperature in °C, on the X axis, years, with labels from 0AD to the year 2000.”
Still not clear? Go join some mega-church.
John Day,
Something is obviously changing in Google; recently, they started fighting the Chinese censorship in all seriousness. Maybe their green bias is also subsiding?
Nick Stokes says:
June 13, 2012 at 12:39 am (Edit)
“With a clear MWP “
Not so clear to me. As I recall, d18O correlates negatively with temperature.
—————————————————————————————————
“Oxygen isotope series are the backbone of deep-time paleoclimate. The canonical 800,000 year comparison of CO2 and temperature uses O18 values from Vostok, Antarctica to estimate temperature. In deep time, O18 values are a real success story: they clearly show changes from the LGM to the Holocene that cohere with glacial moraines.”
http://climateaudit.org/2012/06/12/an-unpublished-law-dome-series/
Alexander Feht says: June 13, 2012 at 5:35 am
“Right above the graph, it says in English:”
Yes, but on the graph it says, equally clearly, d18O. And I’m sure that is right. The numbers are in the usual range for d18O. And proxies are not related to absolute °C, only to anomalies. Otherwise you’d have the task of saying exaqctly where the °C, was measured. It certainly wasn’t at Law Dome. There’s no station there.
Nick, the sentence above the graph says, “On the left is temperature in °C ……”
The numbers run from -23 to -20. I’ve never heard of negative ratio units.
I imagine that the jagged grey lines on the graph are plotted from the d18O ratios but the scale has been interpreted into the equivalent implied temperature.
The do18 proxy is the best temperature proxy we have. Yet the pro-AGW posters do their best to denigrate it.
On the other hand, tree-rings are the worst temperature proxy that we have and the pro-AGW posters believe the tree ring data without question.
This whole science is like that. It’s not science, it’s choosing which data to believe. It’s a “belief system”.
For once I have to sort of agree with Nick Stokes. The graph, though interesting, does not clearly lay out a picture of earlier temperatures…and it is those that we are interested in. Having a y-axis labelled ‘upside down’ does not help, and using the unfamiliar unit of ‘d180’ does not aid our understanding.
If this graph really shows what some have claimed it does…the ‘Death of the Hockey Stick’ and/or the final proof of the MWP, then it is indeed big news.
But for general consumption (ie. anybody who doesn’t have a Masters in the gaseous absorption of ice cores) it needs to be redrawn with familiar y-axis units (C, K or F) and with a readily comprehensible but scientifically watertight explanation of how it has been derived – and all the data published in an easily accessible form.
.
Unless and until this has been done it is better not to run around like Chicken Little making possibly unsubstantiable claims. The recent experience of our Australian friends has shown that premature ejaculation can be deeply problematical – even in a closed circle of supposed mates. Advice that we should heed.
Happy to help if I can, but others probably have better skills than me.
“However, after hearing dozens of different commenters telling “Nick Stokes” he is an idiot with conflicting reasons why, I still don’t have a clear explanation.”
There may, indeed, be conflicting reasons “why” but on the substantive issue there seems to be a consensus. (Just a joke, Nick. I know you’re a clever guy).
What do people think the motivation is to persuade the world that global warming is real? Investment in “green-tech”?
I see at CA that in fact the Law Dome d18O data is available, and has been for some years.
REPLY: Yes but it wasn’t prominently published, which is McIntyre’s point – take care not to thread bomb here or it will be back to the troll bin for you. – Anthony
My analysis of the high resolution ice core data (including Law Dome) clearly shows both the MWP and LIA, http://www.kidswincom.net/climate.pdf.