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
I’m not sure there is anything actually new here. This is not global in scope. The argument remains as to if the Holocene Optimum and the MWP were regional or global remains.
I guess I’m unclear how examining just 26 clams with a lifespan of a mere 9 years gives a reliable estimate of temperatures over more than 2,000 years. Seems like there would be a lotta lotta gaps in coverage that would have to be estimated.
And it’s only related to temps at that particular spot in Iceland.
Now if they get their hands on a few thousand clams from a couple hundred sites around the globe…
It will be interesting to see if the use of “a robotic sampling device to shave thin slices from each layer of the shells’ growth bands.” to the accuracy claimed in this article can be duplicated.
Lief I think the “robotic sampling device ” capable of following the clam’s growth rings accurately was the actual break through and not the isotope ratio analysis by mass spec.
mann will just flip the series
The tastiest and juiciest oysters in the world come from the south of the South Island, New Zealand – Foveaux straight, nearest port Bluff.
Gotta come on down and try some in season.
Shuck & slurp – yum.
But not certain if they can tell the temperature.
OK our clams are very average but surely they can tell the temp.
phlogiston (20:16:56) :
All smaller than clams.
http://www.pcas.org/documents/PagesfromV39N4-5.pdf
Figure 3. Is that a clam? big enough for you? This has been a standard technique for many years, on clams and many other shelled animals. And contrary to many other situations in life, size doesn’t matter in this.
Leif @ur momisugly (19:15:29) :
“The 18Oxygen stuff has been know for more than half a century. See the historical notes I provided. But every so often people has to be reminded of the known known”.
I guess the question that then has to be asked then is why the others have persisted with the problematic tree ring proxies for so long, and why it has been afforded such unjustified credence, when there are more accurate ways of doing it. Blinkers, arrogance, funding, or just ignorance….I dunno.
OK – everyone on this list please KEEP CLAM!
What bothers me about such reports is the little phrase “reveal accuracy of Norse sagas.” The Norse “sagas” don’t need verifying with respect to depictions of climate and travels that are already known to have happened based on finding the settlements. It is the “scientific” studies that are in question. That is, can they or can they not reproduce the known conditions of that day. For example, if a roman historian makes a side remark about the army taking a certain mountain pass, and if that pass is IMPASSABLE today – any temp. proxy must conform to that description of the climate of the time. To read a lot of these studies you would think it is the history that needs verifying when it is the other way around, the proxies must conform to known history!
Granted that not all literature was to be taken as fact, but it is usually easy to pick out the mythology tales from accounts of travel and normal prose literature.
Gail Combs (20:29:24) :
“robotic sampling device ” capable of following the clam’s growth rings accurately was the actual break through
Could be, and opens the door for a much more extensive campaign.
For some reason, when I think Big Clam I think of Pam Anderson.
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
Dave Wendt (18:42:28) :
That was very funny
One pile of clams from one bay in Iceland does not falsify any of the hockey sticks. However, if a whole lot of bays in a whole of lot of places in both hemispheres is sampled for piles of clams there might be something to say regarding hockey sticks.
Then of course there are errors that need to be addressed, as in sampling protocols, lab procedures, species of clams, etc.
I think as proxies go though, this clam thing has promise. And then there’s the clam feast – baked is my favorite, but fried works too. Raw is just plain wrong though (except oysters that is).
I’m sure Michael Mann can show how this is all just oil funded research. One of the oil companies is even named “Shell.” See?
KC (20:37:14) :
Not funny! Now CLAM UP! 😐
@ur momisugly Leif Svalgaard: I don’t understand why tree rings were used then. Just for the shell of it? 😐
Ok, I guess I am out of steam. 😐
Pamela Gray (19:20:35) :
Thousand Foot Krutch — Clam It Up lyrics
LOL! Wow you’re over the top – what have you been drinking today? Hopefully a Bloody Caesar – although you are a ‘USA-an’ and Americans do not properly appreciate this Canadian concoction! It’s like a Bloody Mary only much better. Use clamato juice – a blend of clams and tomato juice – plus a shot or two of vodka, a few drops of tobasco, a splash of Worcestershire sauce, and a squirt of lemon juice, all over ice, and with a stick of celery in a celery-salt rimmed glass. Yum. (Thanks for the entertainment here and recipes in past threads).
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Though I’m partial to clams I’m skeptical about how useful they are as clamometers: currents and upwellings and the like can dramatically affect water temperature quite apart from atmospheric temperature readings. Why oh why didn’t those pesky medievals invent thermometers while they were going about inventing other useful things like mechanical clocks?
Love the Mann-clam pic at the top!
CLAMATOlogy. Clamato is a heresy. If it isn’t, it should be.
Is there a way they measure how long the clam was alive? How do they know it was two years, and not nine years?
@ur momisugly Joe: Quote of the year goes to you my friend
“Sorry sir, but this sounds too much like science. I believe computer models, scientific papers where the raw data is unavailable and conspiracy of big oil is more logical.”
Leif Svalgaard (21:12:55) :
The hard part is not the temperature when the clams lived [that is old hat as I said], but to know the age of the clam and to find old clams that can be dated. Kitchen middens
—
I guess there were too many jokes about clam claims…
Does anyone mind if I mussel in on this thread?
joe (18:00:17) :
Forget about the science, forget about my emails, let me tell you a story of big greasy oil, sending professional squad teams against good scientists like me. Be afraid, woOoohhh.
In this instance, they’d need to send professional squid teams…
Looks like there was a lot of cold-weather famine during the so-called “Medieval Warm Period” ( 950 – 1250 AD ). Huh.
But not to worry, now there is a “Roman Warm Period” to speculate about. Too bad they didn’t include datapoints from the last 350 years or so on this graph:
http://wattsupwiththat.files.wordpress.com/2010/03/clamatologyfig3_mussels.jpg
The GISS temperature anomalies are +/- with respect to 13.9 deg C.
( http://pubs.giss.nasa.gov/docs/1999/1999_Hansen_etal.pdf )
Jan 2010 had a temperature anomaly of 0.71 deg C:
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt
Hence, their calculated temperature for the planet was 14.61 deg C.
Even the “Roman Warm Period” in this Icelandic bay was about 13.5 deg C.
Is this Nature News paper trying to hide the increase with proxy data ?
That’s pretty dangerous, people call for you to be fired over such things.
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.
This will have to be spelled out clearly.
The study used 26 shells obtained from sediment cores taken from an Icelandic bay.
This is an interesting technique for getting temperature proxy data, but they will need to find mollusc shells all over the world in ocean sediment to get a sampling of global paleoclimate. 1000 locations all over the world’s coasts should probably be a good spatial sampling.
The Idso group at co2science has done a lot of work on the MWP —
http://www.co2science.org/data/mwp/description.php
The MWP was mostly warmer than the current period, and it was global.
this data will all have to be thrown out because it is not suitable for all audiences.
WARNING: this news bit contains clams being shaved. Shaving may cause things to heat up. viewer discretion is advised.