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A new type of proxy

There's a fascinating article at Nature's website at the moment, reporting on a new paper in PNAS in which William Patterson of the University of Saskachewan in Canada reveals his new clam-based temperature reconstruction. 

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.

The resolution is remarkable, down to as little as a week and with Patterson holding out the possibility of daily resolution in future. As Patterson puts it, this opens the door to the study of paleoweather and the possibility of studying seasonal changes changes.

The reconstruction is pretty interesting too, with a hint of a little ice age, a clear medieval warm period and the turn of the first millennium appearing as warmer even than medieval times.

But what's really interesting is the modern era. Are current temperatures unprecedented or not? That's what we all want to know. Well, we don't know because Patterson's results seem to stop at 1800 AD.

Perhaps he explains in the full paper. 

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  • Response
    Err, no. Via Bishop Hill, which is kind of ironic due to the study coming from the UofS. :) From the full PDF (PDF, 378K) "The interval from ?230 B:C: to A.D. 40 was one of exceptional warmth in Iceland,...

Reader Comments (21)

Full paper is open access at:

Mar 9, 2010 at 1:40 PM | Unregistered CommenterQ

maybe he is using "the Trick" but stopping in 1800 instead of 2000?

Mar 9, 2010 at 1:50 PM | Unregistered CommenterFred from Canuckistan

That looks like an interesting paper and it is certainly an interesting area for more research.

I suspect that the dating could be a problem in some areas, due to recycling of old carbon from limestone or from igneous and hydrothermal sources, although with a broader array of detectors on the mass spec, input for some of the other dating techniques such as U series disequillibrium could be determined simultanaeously.

Now, how about sacking some PR people to free funds up for this guy?
or am I wissing in the pind?

Mar 9, 2010 at 1:53 PM | Unregistered CommenterKeith

thanks Q

Mar 9, 2010 at 1:54 PM | Unregistered CommenterKeith

We would prefer to analyze a sample consisting of minimum thirty shells each from thirty widely separated sites representing thirty time-periods of no less than 121 years apiece. If results should prove redundant, excellent-- that infers these 29 shells are indeed a valid sample, while confirming the research's conventional temperature time-frames. Absent such grunt stuff, as Feynman used to say, you're talking Freud not physics.

Mar 9, 2010 at 2:08 PM | Unregistered CommenterJohn Blake

A new paper is expected to be published in the near future in the Yorkshire Post describing the method by which a new Central England Temperature record has been reconstructed by blokes with beards delving into the waste bins of Harry Ramsden's fish and chip shops in the triangle formed by the premises at Blackpool, Manchester Airport and Gateshead. The researchers only selected chips which were undamaged and by counting the numbers from each bin and passing the totals through software developed by another Harry (in Norwich, not Guiseley) they were able to prove absolutely nothing at all.

Mar 9, 2010 at 2:08 PM | Unregistered CommenterBrownedoff

Meh, typical proxy crap.

" δ18 O trends primarily reflect changes in ambient water temperature, thereby establishing a re-
cord of subseasonal temperature variation over the lifetime of individual bivalves (∼2 to 9 years). "

Then they give an estimate of ± 0.6 C temperature error. What other changes in the environment will change the δ18 O trends? When are these guys going to learn that they can't assume this stuff? With the clams they could run a series of long term experiments and actually measure the temperature response.

The best I can say is: not as bad as tree rings.

Mar 9, 2010 at 2:14 PM | Unregistered CommenterPaul from Boston

I expect it'll prove to be a clam bake.

Mar 9, 2010 at 2:21 PM | Unregistered Commenterdearieme

The authors point out that temperature measurements of water performed in the region since 1938 range between -1 and +11 deg C. Upon my first perusal of the text, I could not find any other mention of modern times (although this information could be easily incorporated into the paper and is apparently of great interest to many readers. This somehow reminded me of some recent comments at ClimateAudit made by L.T. -- like, e.g., this one or this one).

It is said in the paper that from around 240 BC to 40 AD there was a period of exceptional warmth with temperatures rising to +13 deg C. It is stated that the reconstructed water temperatures for this period called the Roman Warm Period are "higher than any temperatures recorded in modern times". Another period of exceptional warmth was recorded between 600 to 760 AD, with mean maximum annual temperature of +11 deg C. Even taking into account the scarcity of data on modern times in the paper (range -1 -- +11 deg C), it can be inferred from those statements that the past warm periods were significant.

Mar 9, 2010 at 2:22 PM | Unregistered CommenterAnastassia Makarieva

I am taken by the comparison with Icelandic records. But: "Several great famines occurred
in the first century following settlement, such that
“men ate foxes and ravens” and that “the old and helpless were
killed and thrown over cliffs”. How on earth were there foxes in Iceland?

Mar 9, 2010 at 2:31 PM | Unregistered Commenterdearieme

Iceland used to be covered by forests, so foxes should not come as a surprise.

Mar 9, 2010 at 2:37 PM | Unregistered CommenterAnastassia Makarieva

More proxies from the north atlantic are not useful. We already know the MWP was strong in that region. The MWP deniers insist that it was only a regional phenomena.

Mar 9, 2010 at 3:09 PM | Unregistered CommenterTim


I think I'm right in saying that the Arctic fox is the only large mammal native to Iceland. (Amusingly - though less so for Icelanders - they also get the occasional polar bear floating over on ice floes from Greenland...)

Mar 9, 2010 at 4:27 PM | Unregistered Commenteragn

If you pushed me to give an instant verdict on this new proxy I'd clam up. But it's cool to see something original. I was thinking that when I read on the Beeb:

Minuscule tubes coated with a chemical fuel can act as a power source with 100 times more electrical power by weight than conventional batteries. As these nano-scale "fuses" burn, they drive an electrical current along their length at staggering speeds. The never-before-seen phenomenon could lead to a raft of energy applications.

Again, sounds pretty useful. Who of the world's energy experts predicted that one? And what other technology is going to become available in the next 50-100 years? It's mind-boggling that anyone thinks they can predict such things. Real science is fun precisely because it's so surprising.

Mar 9, 2010 at 6:22 PM | Unregistered CommenterRichard Drake


Thanks for the best laugh I've had in a while.

Mar 10, 2010 at 1:26 AM | Unregistered CommenterJamie

"As these nano-scale "fuses" burn, they drive an electrical current along their length at staggering speeds."

Hmmmm. I thought electric current moved at the speed of light. Burning, chemical fuel? Any CO2 given off?


Mar 10, 2010 at 2:52 AM | Unregistered CommenterPaul Maynard

This graph is yet another indication that the world has been gradually cooling since about 0 AD. The more data I see, the more convinced I become that the current interglacial began the process of ending at about 0 AD and we have been in a 2000 year cooling trend. Yes, we will have periods of warming and cooling but I believe the general trend has been, and will continue to be, downward in temperature.

Mar 10, 2010 at 7:35 AM | Unregistered Commentercrosspatch

Paul, OT but here's what it says in the abstract:

Theoretical calculations predict that by coupling an exothermic chemical reaction with a nanotube or nanowire possessing a high axial thermal conductivity, a self-propagating reactive wave can be driven along its length. Herein, such waves are realized using a 7-nm cyclotrimethylene trinitramine annular shell around a multiwalled carbon nanotube and are amplified by more than 104 times the bulk value, propagating faster than 2 m s−1, with an effective thermal conductivity of 1.28±0.2 kW m−1 K−1 at 2,860 K. This wave produces a concomitant electrical pulse of disproportionately high specific power, as large as 7 kW kg−1, which we identify as a thermopower wave. Thermally excited carriers flow in the direction of the propagating reaction with a specific power that scales inversely with system size. The reaction also evolves an anisotropic pressure wave of high total impulse per mass (300 N s kg−1). Such waves of high power density may find uses as unique energy sources.

Any clearer? :)

I'm not bothered by CO2 - not being convinced by the A in AGW - but I take this to be a very fast chemical propagation, with an unexpected electrical pulse as a side effect. I'm not saying we know it will turn out to be useful outside the lab. As always, it was the unexpectness that grabbed me. Nanotech must be fun for that reason.

Mar 10, 2010 at 8:08 AM | Unregistered CommenterRichard Drake

What a total load of bollocks, this mollusc study is!

How porous is this shell? It's buried in what? For how long? And it's how many millimetres thick? ya think a few things might leach in/out over a millenia, or so?

Honestly, why don't we pay these people to go help the nurses in hospitals to give their patients some water, so that they don't die from dehydration? The money would be MUCH better spent.

Mar 10, 2010 at 1:37 PM | Unregistered CommenterBradH

It is odd that the early reaction to this new line of analysis of past temperature has been mostly indifference. In my view, this is quite an extraordinary scientific breakthrough. The technique will no doubt be improved in future providing greater precision for past temperature reconstructions. Moreover, it will enable to take snapshots of past climate on a truly global scale, not just from certain regions that have particular trees or sediments. It will be interesting to see if the technique can be further developed and extended to shell creatures living in-land lakes and rivers. (I am no scientist. Just speculating)

Of course, the most interesting aspect of the preliminary finding in the graph is that -if I read it correctly- the Roman Warm Period was warmer than today as well as the Medieval Warm Period. Such a finding would be quite amazing. It would be the first true nail in the coffin of the AGW hypothesis, since so much of the climate science rely on the paleo data and the supposedly 'unprecedented' nature of the recent warming.

Mar 10, 2010 at 8:36 PM | Unregistered CommentersHx

Using not up-to-date proxy list for marketing bots like putting diesel fuel into gas running car. You get frustrated as the never seem to work for you. All these long hard working hours on projects can go down the drain just because of using bad proxy list.

proxy tool

Dec 3, 2010 at 11:01 AM | Unregistered CommenterShania2010

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