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
Here is a similar one http://www.timesonline.co.uk/tol/news/weather/article7056875.ece
In about the 9th century the Vikings invaded Orkney, which became a colony of Norway until the islands were annexed by Scotland in 1472. The Vikings thrived on farming and fishing, but what was the climate like in those days?
On a sandy beach at Quoygrew on the island of Westray, Orkney, waves have scoured a bank and revealed a Viking rubbish tip of seashells from limpets, possibly used as bait by Viking fishermen between AD800 and AD1200. And those shells have yielded a fascinating archive of ancient climate.
Shellfish grow all year round, and each year of their growth shows up as very thin lines in their shells, giving their age. The temperature of each season can also be read from the proportions of two different forms of oxygen that were in the seas when the limpets were alive — cold seas are rich in one type of oxygen and warmer seas have more of the other type. And the Orkney shells taken from the 9th and 10th centuries show that sea temperatures, and hence the climate, were similar to today. However, detailed analysis revealed that summer temperatures were slightly warmer than today, and winter slightly cooler. Why the seasons were more exaggerated in Viking days is not clear, though.
In fact, the climate of modern Orkney and Shetland is remarkably mild all year round and has the smallest daily temperature range over the year in the UK. This is thanks to the mild waters of the North Atlantic Drift, the extension of the Gulf Stream, which keeps the islands warm in winter but cool in summer. That said, local people say that they have nine months of winter and three months of bad weather.
Hit the road, Manniacs!
A new way to fabricate the past is at hand.
I’m very sceptical of the clam proxy. Studies like this reinforce to me the unsoundness of using paleoclimatology as a basis for public policy.
What distinguishes paleoclimatology from a soothsayer reading animal entrails?
A scientific study would offer a falsification against known temperature records, i.e. cutting down more trees in modern times for dendro, or in this case, grow the clams in a salt water aquarium and see what effect known and controlled temperatures have on a double-blind proxy reconstructions (and any “divergence problems”).
Until then you may as well be slaughtering aurochs to find out paleo temps.
This clam proxy reconstruction, using only 23 clams, seems not to offer a falsifiable comparison to known temps, and ends well before 1800.
Perhaps it’s proto-science, and clam proxy reconstructions will in the future be tested against known temperatures. But it’s instructive that such a falsification test seems to be considered unnecessary in the “science” of paleoclimatology, where “divergence problems” are treated as mysteries rather than falsifications. That are disappeared by Yamal style sample selection, rather than held up as scientific success through experimental failure (a la Michelson-Morley and luminiferous aether).
@ur momisugly Al Gore’s Holy Hologram (18:36:30) :
“The Roman Warm Period did not exist because Wikipedia felt fit to delete a well resourced article on it.”
The Wikipedia deletion log shows the article being deleted on 11 December 2008 at the request of the author. See:
http://en.wikipedia.org/wiki/User_talk:Andrew_c#Roman_Warm_Period
This deletion log also says the article was merely a pointer to a non-existent article on Roman Age Optimum.
So, do you have any more detail on the deleted article?
So could this be the final confirmation that “clam ate” change is real?
Okay, I’ve had a chance to read the paper and look at one or two of the cited references. I want to make just one point here with regard to the water isotope composition.
The paper states that for the salinity range 33.99 to 35.15 parts per thousand the oxygen isotope composition of the water will vary by 0.16 per mille corresponding to an environmental temperature uncertainty of +/-0.6 degrees C. They cite Smith et al 2005 for the data on salinity – water isotope composition. This latter study looked a t very few samples and found a gradient between oxygen isotope composition and salinity of between 0.25 and 0.32. Applying this to the Patterson et al salinity estimates suggests an actual water composition variation of closer to 0.29 to 0.37 per mille. This translates to an error in temperature of close to 1.4 to 1.8 degrees C.
However, there is some doubt as to the validity of the Smith et al mixing line. My own work (Freer, Dennis, Heywood and Boswell, 2001) has a North Atlantic shallow water oxygen isotope – salinity gradient of 0.59. raig and Gordon (1965) found a gradient of 0.61 and Fairbanks (1982) a gradient of 0.63. All these later studies are using much more extensive North Atlantic water data sets. If we use the average gradient of 0.6 taken from these studies then we find the range of water oxygen isotope compositions in the Patterson et al study to be 0.7 per mille. This equates to a range in temperature of 3.3 degrees C.
This is close to the range of temperatures reported in the Patterson et al study.
The moral is that one has to have a deep understanding of the water oxygen isotope composition to be able to interpret carbonate derived temperatures. Even for marine systems this is not an easy task.
references
Craig and Gordon, 1965, Deuterium and oxygen-18 variations in the ocean and the marine atmosphere in Stable Isotopes in oceanographic studies and palaeotemperature, Spoleto Conference Proceedings (ed. Tongior, E) 9-130
Frew, Dennis, Heywood, Meredith and Boswell, 2000, The oxygen isotope composition of water masses in the northern North Atlantic, Deep Sea Research, 47, 2265-2286
Fairbanks, R, 1982, The origin of continetal shelf and slope water in the New York Bight and Gulf of Maine….., J. Geophys Res., 87, 5796-5808
Smith et al., 2005, Temperature reconstructions for SW and N Iceland waters over the last 10ka……., Quaternary Science Reviews, 24, 1723-1740
The Tree versus Clam wars. I can see it now. Giant trees versus giant clams in a conflagration to out ring each other. Might there be some clams or other shave-able entity near the area where Mann got his trees? Now that is a temperature comparison I would pay many clams to see.
Errr – was it political correctness that prevented them displaying any clam data more recent than 200 years old as per the graph? It would have been nice to see the paleo data compared to the supposed anthro-carbon era.
What controls the formation of O18? I don’t remember. I think it is unlikley that it is some perfect proxy for temp.
Why does the graph stop at year 1800?
Anybody find it odd that the graph stops at year 1800? Are they holding back the recent data because it shows no warming? Maybe it shows a hockey stick?
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 bogus alarm is going off!
I don’t know about his other reconstructions, I just flat do not believe the above statement.
from the number watch
Langmuir’s Laws of bad science
1 .The maximum effect that is observed is produced by a causative agent of barely detectable intensity, and the magnitude of the effect is substantially independent of the intensity of the cause.
2. The effect is of a magnitude that remains close to the limit of detectability, or many measurements are necessary because of the low level of significance of the results.
3. There are claims of great accuracy.
geez, and here I was thinking I’m the biggest troll around.
C’mon, is’t that hard to read 5 pages with pictures, before commenting?
“Roger Knights (00:31:40) :
The reason tree rings are attractive is that each tree lives much longer than the typical clam. It will be very helpful of giant clamshells can be located. Is there some way that ground-penetrating radar can be used on the seafloor to detect such large shells?”
Doubtful. Radar doesn’t work underwater, and has limited penetration through water from above. Sonar would be problematic as well. My last tour in the navy was in mine warfare. Even large (500-1000kg) mines buried in mud and sand can be a challenge to find using the best sonar equipment.
It is implicit in this study that there are and there will be a big and increased production of anthropogenic CLAMS due to the increase in anthropogenic CO2, which these creatures capture without receiving any carbon credits in exchange!!!
SInce water temp is affected by depth, how is water depth accounted for? Clams do move , there are drop offs on the ocean floor. Where they were found does not mean that that was where they had been living. n=26?
David Byrd (04:52:44) :
It’s somewhat disappointing to read the sarcastic attempts at humor reflected in many of the comments regarding an analytical method which shows great promise compared to what passes as present day accepted climatological methodology. The application of chemometrics and ANNS (Artificial Neural Networks) has provided insights into areas that were previously untenable via the accepted methodologies. The methods described here may provide an extremely valuable insight into climate history that is sensitive, precise and reproducible. This approach represents a definite improvement over dendroclimatological methods.
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My problem is that I am not aware of any studies that correlate surface temperatures with ocean temperatures. For example, during the warming temperatures that we experienced in the late 1980s and early 1990s (remembered anecdotally by experiencing some brutal heat waves in Eastern Canada) the sea temperatures on the Grand Banks dropped substantially – to the point that fisheries scientists at the Department of Fisheries and Oceans are convinced that this temperature drop, rather than over-fishing, was the main contributor to the collapse of the groundfish stocks. The only coincidence with surface temperatures would have occurred in 1992, when world temperatures dropped due to the Mount Pinatubo explosion, and a moratorium was put on the Western Atlantic cod fisheries because by then there were virtually no fishable populations.
Remember, too, that last year we experienced a year without a summer, but sea surface temperatures reached record highs. I would just like to see a clearer linkage between surface climate and oceanographic phenomena (aside from major phenomena like the El Nino and La Nina). At best, what these clam studies could reveal, surely, would be trends at the multidecadal level. Not sure what exactly a weekly resolution would actually reveal about climate, whether local (which is the only claim made in this study, as Willis Eschenbach points out) or globally.
Nothing new. To Mann, AGW has always been a shell game.
During the Great AGWarming Period, 1989-2009, Science and Nature were frozen tight, during the Great AGCooling Period, 2009-TBD, Science and Nature are warming up.
The rate at which Science and Nature publish real scientific information is inversely proportional to the perceived temperature of the data submitted.
Does anyone else perceive a change in the “whether” at Science and Nature?
A new earthquake in Chile, a few minutes ago:
http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/us2010tsa6.php
1: nothing new here [move on 🙂 or rather go find some old clams, see below]
2: the real difficulty [and why clams have not been used so much as trees] is that it is very hard to find clams that can be dated as well as trees [on a time scale of centuries].
3: I said people need to be reminded about known knowns, not known unknowns.
@jaymam (01:02:19)
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I think this has been covered many times before, and that Paul Hudson received a single email that contained a few other quoted emails, but not the entire Climategate emails.
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Paul Hudson | 13:07 UK time, Monday, 23 November 2009
I was forwarded the chain of e-mails on the 12th October, which are comments from some of the worlds leading climate scientists written as a direct result of my article ‘whatever happened to global warming’. The e-mails released on the internet as a result of CRU being hacked into are identical to the ones I was forwarded and read at the time and so, as far as l can see, they are authentic.
http://www.bbc.co.uk/blogs/paulhudson/2009/11/climategate-cru-hacked-into-an.shtml
Moderators, why was my post deleted? I see someone used the same joke later on. What gives?
@ur momisugly Ryan Stephenson (03:02:00)
“tree ring densities are affected by so many factors, not just temperature – CO2, for instance, can have a big impact”
Indulge me in a thought experiment, if you please.
Logically speaking, temperature (A) is estimated by looking at tree ring density (B) because the two are correlated. However, tree ring density (B) also correlates to CO2 (C). As a result, using tree ring density as a proxy for temperature will necessarily correlate temperature and CO2, it’s tautological. A therefore B, B therefore C logically results in A therefore C, true by definition, no research required. If you wish to link temp to CO2, this is guarantee to do it every time.
In other words, you’ve already stacked the deck, and my question is: would it not be reasonable for a research in this field to be aware of this, and know the outcome in advance? And if so, what conclusions can be drawn about the research/researchers in question?
What is needed is a combining of many proxies which should provide a good general description of historic climate. The peaks and troughs when viewed overall would help distinguish a timeframe consistency. Why just look at individual proxies? Multiple proxies should reduce noise as outliers would be eliminated.