There’s a new article at Nature News where they report on an amazing new paleoclimatology breakthrough with temperature reconstructions using clamshells. The Nature article reports on a new paper in PNAS from William Patterson at the University of Saskachewan. Here’s a short excerpt:
The study used 26 shells obtained from sediment cores taken from an Icelandic bay. Because clams typically live from two to nine years, isotope ratios in each of these shells provided a two-to-nine-year window onto the environmental conditions in which they lived.
Patterson’s team used a robotic sampling device to shave thin slices from each layer of the shells’ growth bands. These were then fed into a mass spectrometer, which measured the isotopes in each layer. From those, the scientists could calculate the conditions under which each layer formed.
Unlike counting tree rings which have varying widths due to all sorts of external influences such as rainfall, sunlight, temperatures, available nutrients, and available CO2, this method looks at the levels of different oxygen isotopes in their shells that vary with the temperature of the water in which they live. One simple linear relationship.
The data resolution from isotope counts is incredible.
“What we’re getting to here is palaeoweather,” Patterson says. “We can reconstruct temperatures on a sub-weekly resolution, using these techniques. For larger clams we could do daily.”
The reconstruction is shown below. We see familiar features the little ice age, the medieval warm period and the downturn which led to the extinction of Norse settlements on Greenland.
And the feature of this reconstruction to surely stick in the craw of many who think we are living in unprecedented times of warmth is the “Roman Warm Period”. Have a look:
From Nature: Shellfish could supplant tree-ring climate data
Temperature records gleaned from clamshells reveal accuracy of Norse sagas.
Richard A. Lovett
Oxygen isotopes in clamshells may provide the most detailed record yet of global climate change, according to a team of scientists who studied a haul of ancient Icelandic molluscs.
Most measures of palaeoclimate provide data on only average annual temperatures, says William Patterson, an isotope chemist at the University of Saskatchewan in Saskatoon, Canada, and lead author of the study1. But molluscs grow continually, and the levels of different oxygen isotopes in their shells vary with the temperature of the water in which they live. The colder the water, the higher the proportion of the heavy oxygen isotope, oxygen-18.
The study used 26 shells obtained from sediment cores taken from an Icelandic bay. Because clams typically live from two to nine years, isotope ratios in each of these shells provided a two-to-nine-year window onto the environmental conditions in which they lived.
Patterson’s team used a robotic sampling device to shave thin slices from each layer of the shells’ growth bands. These were then fed into a mass spectrometer, which measured the isotopes in each layer. From those, the scientists could calculate the conditions under which each layer formed.
“What we’re getting to here is palaeoweather,” Patterson says. “We can reconstruct temperatures on a sub-weekly resolution, using these techniques. For larger clams we could do daily.”
It’s an important step in palaeoclimatic studies, he says, because it allows scientists to determine not only changes in average annual temperatures, but also how these changes affected individual summers and winters.
“We often make the mistake of saying that mean annual temperature is higher or lower at some period of time,” Patterson says. “But that is relatively meaningless in terms of the changes in seasonality.”
For example, in early Norse Iceland — part of the 2,000-year era spanned by the study — farmers were dependent on dairy farming and agriculture. “For a dairy culture, summer is by far the most important,” he says. “A one-degree decrease in summer temperatures in Iceland results in a 15% decrease in agricultural yield. If that happens two years in a row, your family’s wiped out.”
Technically, the molluscs record water temperatures, not air temperatures. But the two are closely linked — specially close to the shore, where most people lived. “So, when the water temperatures are up, air temperatures are up. When water temperatures are down, air temperatures are down,” Patterson says.
Read the complete article at Nature News
Sorry, found it. Please ignore David Ball (07:22:00) : Must open eyes and insert coffee !!! I should know that you guys wouldn’t let me down.
This appears to be a good reconstruction. Typical of climate reconstructions I’ve seen over the past 50 years, before paleoclimate was hijacked by political hacks. My only complaint is using this line:
And the feature of this reconstruction to surely stick in the craw of many who think we are living in unprecedented times of warmth is the “Roman Warm Period”. Have a look:
Which is specious as the chart ends in 1700, there is no comparison to modern climate depicted.
There are 26 ‘brackets’ at the bottom of the chart above with the chart spanning from approx. -400 AD through to 1800 AD; do these brackets represent the 26 sample clams in this study (I think they do, but, I must phrase this in the form of a question and make no assumptions)?
If so, the longest period encompassed by one of the last brackets would seem to depict a period of approx. 250 years.
Why, then, is this statement in the introduction: “Because clams typically live from two to nine years …”
(No, I have not read the paper; the answer probably lies therein.)
.
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I imagine WUWT advises people like the author of this article that you’re putting their work up for comments and that they’re welcome to drop by and comment if they wish. I further assume that the good author of this piece has decided to remain mum for various personal and professional safety/security reasons that do not have to do with us, or WUWT, but rather with his colleagues and his professional associations. Are we such lepers?
“Author: vigilantfish”
About the water temperature.
We are not interested in the water temperature but in the fractionation which occurs as a result of air temperature. Your comment more of less proved something: brutal heat at the same time as cold water… evaporation and guess what changes the isotope ratio?
Shell growth is irrelevant provided there is some, it is the composition of the shell which matters, ie. if they grow slowly in cold water that doesn’t matter.
Wondering Aloud (06:12:50) :
What controls the formation of O18? I don’t remember. I think it is unlikley that it is some perfect proxy for temp.
The fundamental process is that when water evaporates, the lighter isotopes 16O evaporates more than the heavier 18O, and conversely when rain precipitates, so there will be fractionation depending on temperature because temperature controls the equilibrium between vapor and condensed phases.
Not to be overly critical and take this as a friendly suggestion, but why are there a lot of people commenting before they’ve read the paper? That seems a bit strange to me. C’mon, folks… READ!
A bunch of the comments posted here wouldn’t have been posted had reading come before SWAGs.
An elegant technical approach whose ramifications may become clear through the next 20 years.
I do think it critical though, to examine really carefully quite a few assumptions stated in the article to be sure they are actually true.
Without doubt though, if you can accurately data samples by another means, then the fine mapping will now become possible.
A spur to more accurate interannual dating technologies, perhaps??
Actually, what this proves is how readily people are ready to jump up and make half baked claims when they haven’t read the paper. It says nothing about the global climate.
Erm, no. I said I had to be equally skeptical of the REPORT – not the scientific paper. In other words, the quoted article which says, “Oxygen isotopes in clamshells may provide the most detailed record yet of global climate change, according to a team of scientists who studied a haul of ancient Icelandic molluscs.”
As I said, the science behind this appears to be much stronger than for tree ring data but they really need to broaden the data collected and verify the technique that worked in an Icelandic bay works equally well across the world and establish the air/water temperature correlation before it becomes a good tool for assessing GLOBAL climate conditions.
Perhaps I should have been clearer (proof that one should reconsider hitting “Submit” when typing something an hour after normal bedtime) but what I was reacting to was the immediate reaction I saw of “see, this proves the AGW proponents are wrong”. It proves nothing of the sort — what it DOES prove is that there may be a better way to extract paleoclimate information than tree rings and a broader study using this technique may therefore prove the AGW proponents are wrong.
savethesharks (22:50:28) :
Darn I see that pun was nabbed hours ago so I can’t claim it here!
Yeah, those damn clam-jumpers!
As an environmental biologist by training, I’m highly skeptical of this technique. Mollusc shell growth and structure is dependent upon many factors besides temperature including water chemistry, adequate diet, predation etc. The seabed is a very unstable environment due to sedimentation, toxin accumulation etc.
I guess I’m skeptical about clam change.
<blockquote A C (00:43:43) :
I’m worried about that Roman Warm Period. Didnt the Roman Empire collapse?
That’s why several in the climate science community are trying to push to call the current period the Skeptics Warm Period.
PS. Michael Mann’s least favorite musical – “Clamity Jane”!
One has to wonder why the recent clam data post 1660 was not included, were they asked to remove it?, didn’t do it? or thought they wouldn’t get it published if they included it? I wish the authors would state why the more recent period wasn’t included.
The picture of Mann, above, is very revealing. I –for some reason– always thought he was taller. The clams give better perspective and proportion I guess.
Dr A Burns (20:50:34) :
Off topic, but is NORSEX fiddling the data ?
Yesterday NORSEX showed Arctic sea ice right on the average line, now its been dropped half an SD below it.
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
REPLY:
Look at the graphs again. What they did was add in the average (black) and error (grey) for some other data probably the usual 1950 to 1980 time period when the ice was at maximun and the temp at the lowest for the modern era.
I did a search on the research proposal and it seems it was supposed to be until the present, so the question is why isn’t the present data… present?
here is the proposal
http://www.sciencestorm.com/award/0326776.html
and a clip
“Seasonal to annual temperature estimates will be achieved through analysis of 60 individuals, with life spans of two to ten years, that lived during modern times, through the Settlement of Iceland (AD 871) and beyond the interval of human impact to c. 2000 years ago. The use of the micromilled molluscs in marine cores is the only way, at present to obtain seasonally- to-annually resolved climate data from Iceland, beyond the instrumental and documentary record. The short, but annually resolved records are placed within an environmental framework through analysis of other traditional proxy records. Drawing on earlier analyses of these cores, major environmental changes of the past are identified. These include a prolonged “cold” interval between 70 and 400 yr B.P. (ca. AD 1930 back to 1600), an interval with lower ?18O (CaCO3) (warmer) values around AD 1000, and a cool interval centered at AD 670. The project will select molluscs for analysis within these .warm. and .cold. intervals. In order to study the human dimensions of these changes, emphasis will be placed on the period from the Settlement of Iceland (c. AD 871) to the present.
David Ball (07:33:39) :
Please post (a link to) a photo of you inserting coffee as described.
@_Jim
The 26 samples are mentioned to be -representative- of the different time periods.
EJ (21:45:44) :
26 Shells? Really? Should I cry or is this an impressive sample size?
A minimum of thirty would have been better and that is if the samples all belong to the same distribution. However given cost of testing you generally do not get to look at the desired sample number. What this study does is show it is worth while to continue to pursue this line of scientific enquiry.
here is the entire thesis that the paper came from, seems nothing more recent than 1660
http://library2.usask.ca/theses/available/etd-01252007-101516/unrestricted/K.Dietrich_thesis.pdf
The data set stops at ~1650AD. Question, why didn’t he continue on the data set to the current century? I would like to see the correlation of the clam data set to the current data set of temperature readings.. I can envision an offset between air temp and water temp. But if there is measurement data for the water temp where the clams were harvested, then wouldn’t it show a closer correlation than the tree ring data?
Just playing the part of a skeptic, posing questions to the information provided.
Everyone, remain clam!
This IS interesting work. I hope similar studies are being pursued using clams from other marine estuaries around the planet. If the precision purported holds up, a reliable measure of local/regional temperature and climate may be achieved.
As some have already stated, but it would be interesting to see clamatology done up to today with an proportionally amount of clams, so one can easily ad hoc it to their current plot.
Oh and did you lovely loonies truncate one of my ever so witty lines or did the text parser manage to auto-magically do that by it self? [The whole geez blah blah hilarious religious funny reference.]
Paul Dennis (23:47:42) :
I’ll post my comments on the Patterson paper on my blog. I’ve been conspicuously quiet in posting due to an illness so apologise to those who may have been returning over the past month to find no new posts.
Reply:
Where is your blog and perhaps you could do a guest post here at WUWT.
Dear Sirs,
You realize that were one to try, one could find 10,000 Quaternary Research papers covering aspects of the above results (which seem like good work by the way). The on-going mystery is why an entire sub-discipline was in essence ignored in the period of AGW hypothesis formation. You realize of course that Kenneth of CRU email fame would exclude the above molluscan isotope study from consideration out-of-hand because dating control is not at an annual level (thus the preference for dendro.). What the dendrochronologists (with the exception of Jan Esper and a few others) do not usually admit is that the mathematical function of detrending (in essence, the math used to construct wiggle-matches between tree ring seuences) itself removes low frequency (long-term) climate change signals. Along the lines of the above study, D. Geography at U. Cardiff (Wales) is presently collecting a mollusc series that will comprise an absolute (annual level resolution chronology) in the eastern North Atlantic that will match the above study with respect to indicative value strength, as well as being chronologically very precise.
Yours sincerely,
Bruce M. W. Albert, Ph.D., PDRA, Durham University
Paul Dennis (05:35:04) :
Thanks Paul for dropping in. its always fun to read the “mix” of comments, from the low to the high, from the curious to the close minded, from the uninformed to the informed. ( you and leif’s always being top shelf of course )