A new paper has been published by Sicre et al in Earth and Planetary Science Letters entitled: ‘Decadal variability of sea surface temperatures off North Iceland over the last 2000 years.’
The Abstract states:
Ocean variability at decadal time-scales remains poorly described partly because of the scarcity of high temporal resolution marine records. Here, we present a reconstruction of Sea Surface Temperatures (SSTs) over the past two millennia at unprecedented temporal resolution (2 to 5 years), from a marine core located off North Iceland. Alkenone paleothermometry was used to infer SST variability, and tephrochronology to build the age model. Spectral analyses of the SST signal indicate intermittent 20–25 year oscillations, with periods of strong and weak power, that are likely reflecting the ocean response to wind forcing, presumably the North Atlantic Oscillation (NAO). Warmer SSTs and paleo-magnetic proxy data, between 1000 and 1350 year A.D., overlapping the Medieval Warm Period (MWP), suggest enhanced heat transport across the Denmark Strait by the North Icelandic Irminger Current (NIIC). This is in contrast with the subsequent period, which includes the Little Ice Age (LIA), showing continuous cooling towards the 20th century. Reduced NIIC flow through the Denmark Strait likely resulting from higher freshwater and sea ice export from the Arctic would account for the observed colder conditions.
Keywords: Decadal variability; Sea surface temperature; North Atlantic; Alkenones; Medieval Warm Period; Little Ice Age; Iceland
The authors state in the Discussion:
“A remarkable feature of the North Icelandic SST record is the abrupt increase of around 1–1.5 °C occurring within a decade around 980 A.D., maybe imputable to the onset of the MWP. This sustained warm period, lasting for several centuries, ends by a sharp cooling around 1350 A.D., following a brief cold episode around 1250 A.D. The same pronounced centennial-scale warming, though not exactly synchronous, has been documented by the distant records from the Sargasso Sea (Keigwin, 1996), the Eastern sub-tropical Atlantic (deMenocal et al., 2000) and estuarine sediments of Chesapeake bay (Cronin et al., 2005), confirming its widespread occurrence in the North Atlantic region.”
Hat tip to CO2Science.org
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Uh oh, some one is sharpening the stakes again. This on top of Anthony Watts article about water vapor dropping has made for an interesting day.
Creepy/el Creepo/Luke your up!
CoRev, editor
http://globalwarmingclearinghouse.blogspot.com
Oh, but this is just more NH data, we need a worldwide…a global measure of past temperature! Yeah, that’ll stick!
Paul: Let’s catch up with that new CSIRO research on ocean data in Nature today.
Then there is that WWF funded research on whales feeding in the Southern Ocean… ABC
The WWF is an extremist fundamentalist green group, and any of their “research” must be treated as sus.
Anything but the topic, eh boys?
After viewing this solid evidence of a 1000 year declining trend it is now quite obvious that a good dose of warming would be most beneficial.
That very last little peak in the graph is the very same 1998 peak that the gonzoscenti used to extrapolate into the stratosphere. But any suggestion that it was not ENTIRELY within the historical range of variation is pure bunkum.
CoRev; you’d think Watt’s report on the NOAA graph showing a drastic decline in specific humidity since 1990 would give pause and be headline news, since it tears the guts out of AGW and its dependence on +ve feedback; but no, on ‘our’ ABC, the news is the WWF commissioned findings showing/predicting (I couldn’t hear properly because I was stunned) warmer sea temps and shrinking ice; which of course is exactly the opposite of what is happening. It’s straight out of Orwell; black is white, cold is hot; if this keeps up I’m going to become an alarmist.
Ian Mott – “After viewing this solid evidence of a 1000 year declining trend it is now quite obvious that a good dose of warming would be most beneficial.”
Of course seeings as the North Icelandic ocean is completely representive of the global ocean – no wait it isn’t.
“Reduced NIIC flow through the Denmark Strait likely resulting from higher freshwater and sea ice export from the Arctic would account for the observed colder conditions.”
Funny also how proxies and statistical methods to sort noisy data are OK when they confirm what you want to hear. Goes along with the faulty parameter ridden computer models that are also somehow OK when they also confirm the contrarian view.
Well whatever it is the polar bears seem to have Iceland on their vacation list – or is that new real estate?
And you Ender, I suppose you’ll still be applying 30+ blockout as the ice forms around your ankles?
Home grown research blog style is not science!
Watt Remoteness n Co above, think they are doing by searching everywhere but under their noses completely eludes me. Contributors to other “climate” blogs should realize, doing the Google is the easy bit, also creating original data requires some skill in the practice.
Anyone sniffing round looking for scraps is bound to dine on rubbish.
King Canute,
The last decade has created a “climate shift” of knowlege weather wise [sadly at taxpayers expense] which gives us chattering classes plenty to talk about.
But looking under my nose I find; the weather is great, the sky is clear, the grass is green, the robins sing.
It pays to go for a walk and take note.
With all the billions spent on “the anxiety machine” I must admit it has made me anxious, though still sceptical.
Helps to keep the weight down.
Gavin,
That ABC story on warming oceans and whales in trouble was based on new “estimates” of temperatures. Does that tell us anything?
How can you be having record levels of sea ice as well as record ocean warming?
Gavin – I saw the CSIRO sea level ‘research’ – I’m still laughing! More estimates and adjustments.
Junkscience.com:
Ooh! Ooh! Let us get this one: 2.5″/42 years equates to… 2.5/42*100 = ~6″/century. And the average over millennia is thought to be… ~8″/century, meaning the rate 1961-2003 is only three-fourths that expected, right? What do we win?
Ender – let’s pass this reconstruction to Mann and his army of ‘independent’ co-workers to receive the straight line treatment.
Anyone here live in a ‘global mean’ region? No, I thought not.
Climate is just doing what it has always done – changing, with the Arctic region the warmest as usual, while the Antarctic is also business as usual in an interglacial:
http://www.jennifermarohasy.com/blog/archives/003126.html
C’mon Paul; that thread hardly floated.
Ender correctly states:
“Of course seeings as the North Icelandic ocean is completely representive of the global ocean – no wait it isn’t.”
Must be why they have collected paleo data for areas worldwide over at:
http://www.co2science.org/data/mwp/mwpp.php
Check it out. You might actually LEARN something!!
Brian M Flynn (May 19 7.37am 2008) commenting on Atmoz “Global sea levels, another hockey stick” makes an interesting contribution in contrast to KuhnKat who wades around in these debates on various blogs.
BTW Brian, a “spectator” asks interesting questions at CA too.
No Ender, I did not suggest that iceland data was a global proxy but it is certainly a very good guide to the influences on the Greenland Ice Sheet. And this data makes it very clear that temperatures have a very long way to go before they get anywhere outside the historical range of variation.
Ergo, don’t expect any ice sheet collapse any time soon. In fact, do let us know when there has been at least 1.5C of additional temperature increase and we might give you 30 seconds of our time. If we are all still around in year 2158.
Thanks KhunKat, this graph for Peru is consistent with the Iceland data. http://www.co2science.org/data/mwp/studies/l1_perushelf.php
Ans so is this from NZ http://www.co2science.org/data/mwp/studies/l1_nzcave.php
Looking like the only anomaly is the IPCC climate muddles.
“For the first time, we can provide a reasonable account of the processes causing the rate of global sea-level rise over the past four decades – a puzzle that has led to a lot of scientific discussion since the 2001 IPCC report but with no significant advances until now,” says Dr Catia Domingues of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart.
The research gives significantly greater credibility to the way computer models simulate the degree of warming in the world’s oceans, a key feature of sea-level rise and climate change.
“Following the review of millions of ocean measurements, predominantly from expendable instruments probing the upper 700 metres of the ocean, we were able to more accurately estimate upper-ocean warming, and the related thermal expansion and sea-level rise. We show that the rate of ocean warming from 1961 to 2003 is about 50 per cent larger than previously reported”, says Dr Domingues.
“Our results are important for the climate modelling community because they boost confidence in the climate models used for projections of global sea-level rise resulting from the accumulation of heat in the oceans.”
KC; where did you get that quote? It’s not from the Domingues paper abstract, and gavin’s media link about the paper is no longer operative; my understanding is that this study is an interpolative one using some some sort of monte carlo process made necessary by the “sparse data coverage”; your quote makes it sound as though they had actual data and not computer estimates.
cohenite
I think KC’s quote is from a media summary – it has a faint ring of familiarity to it.
I do like Michael Crichton’s comment “One of the defining features of religion is that your beliefs are not troubled by facts”.
cohenite: SEA below
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/06/18/scisea118.xml
“it’s definitely the water
the ‘science’ of AGW is shot to bits; atmospheric specific humidity has been dropping sharply since 1990 according to NOAA; the significance of this is that since the ‘heating’ effect from CO2 is miniscule, ipcc has invented +ve feedbacks from water vapor; but water vapor levels have dropped precipitously, so any +ve feedback has been declining at a time when they ‘assert’ temps have been increasing! But it all makes sense now since, apart from a couple of anomalous El Nino years like 1998, temps have actually been falling, or have been flat; so it’s definitely the water”