From CO2 Science, another peer reviewed paper with a paleoclimatology reconstruction based on cores containing plankton shells, show that both the Medieval Warm Period (MWP) and the Little Ice Age (LIA) can be seen in Indonesia. In the past, critics have said these events to be “regional” implying they occurred only around Europe, due to lack of historical records in other regions of the world.
Since the Oxygen18 isotope dating method seems well proven, it would seem this study has a good basis for its claims. Even RC’s Gavin Schmidt likes it.
Co2 Science writes:
From the authors’ Figure 2b, adapted below, we calculate that the Medieval Warm Period was about 0.4°C warmer than the Current Warm Period.
The Makassar Strait (Wikipedia)
Foraminifera samples.
Description
Oppo et al. derived a continuous sea surface temperature (SST) reconstruction from the Indo-Pacific Warm Pool (IPWP), which they describe as “the largest reservoir of warm surface water on the earth and the main source of heat for the global atmosphere.” This history — which was based on δ18O and Mg/Ca data obtained from samples of the planktonic foraminifera Globigerinoides ruber found in two gravity cores, a nearby multi-core (all at 3°53’S, 119°27’E), and a piston core (at 5°12’S, 117°29’E) that were recovered from the Makassar Strait on the Sulawesi margin — spans the past two millennia and, as they describe it, “overlaps the instrumental record, enabling both a direct comparison of proxy data to the instrumental record and an evaluation of past changes in the context of twentieth century trends.” Reconstructed SSTs were, in their words, “warmest from AD 1000 to AD 1250 and during short periods of first millennium.”
Reference
Oppo, D.W., Rosenthal, Y. and Linsley, B.K. 2009. 2,000-year-long temperature and hydrology reconstructions from the Indo-Pacific warm pool. Nature 460: 1113-1116.
“MrX (12:34:53) :
… I wouldn’t bring plate tectonics into this. It’s a very whacky idea that gained prominence because the older theory couldn’t explain the mechanism. Plate tectonics has changed explanations countless times on its own mechanics and will change again. If you look at the geometry, PT is physically impossible for long distances. …”
PT is at present the only viable model going for large scale geological phenomena. It is the only one that DOES handle the geometry. The geosynclinal theory never did. There are no other explanations that integrate the motions of large scale faults like the San Andreas, volcanic arcs, their geographic correlation with extremely deep trenches, space/depth patterns in seisimicity along continental margins and particularly along subduction zones, triple junctions and a number of other phenomena such as magnetic striping, into one relatively neat mechanical model. Most objections are focused on crustal rigidity and don’t want to accept empirical and laboratory data of plasticity at depth; there’s a propensity to argue that rocks are brittle and can’t really deform. A theory can remain viable as long as it continues to examine itself, which is why the changing ideas about the mechanisms PT are a good thing.
The Indonesian study isn’t the only one showing that the MWP extended well beyond Europe. Would you believe Mono County, California?
Late Holocene forest dynamics, volcanism, and climate change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, California, USA
Constance I. Millar, John C. King, Robert D. Westfall, Harry A. Alden, Diane L. Delaney
Abstract
Deadwood tree stems scattered above treeline on tephra-covered slopes of Whitewing Mtn (3051 m) and San Joaquin Ridge (3122 m) show evidence of being killed in an eruption from adjacent Glass Creek Vent, Inyo Craters. Using tree-ring methods, we dated deadwood to AD 815– 1350 and infer from death dates that the eruption occurred in late summer AD 1350. Based on wood anatomy, we identified deadwood species as Pinus albicaulis, P. monticola, P. lambertiana, P. contorta, P. jeffreyi, and Tsuga mertensiana. Only P. albicaulis grows at these elevations currently; P. lambertiana is not locally native. Using contemporary distributions of the species, we modeled paleoclimate during the time of sympatry to be significantly warmer (+3.2°C annual minimum temperature) and slightly drier (−24 mm annual precipitation) than present, resembling values projected for California in the next 70–100 yr.
http://www.fs.fed.us/psw/publications/millar/psw_2006_millar027.pdf
The Medieval Warm Period happened, no if or buts.
To deny the occurrence is to deny reality, geologists and archaeologists have never denied the existence of the MWP.
Some ‘scientists’ who because of it’s inconvenient warming attempted to efface fact from their own fiction. Time and again, more and more confirmation of the MWP comes to light and each fact just simply reinforces the obvious; that the cover up and fudged computer algorithms (Mann) cannot deny the truth and that their flawed hypothesis is further blown out of the water.
Now that is denial for you.
“Bonehead (13:13:20) :
Woah! Lets not get too excited… these are “proxies” aren’t they?!? Or are there “good proxies” and “bad proxies”???”
There are many proxies untouched by M. Mann, so the answer to your question is yes.
To be moderately nit-picky, I suggest you reorder a couple sentences to:
“Since the Oxygen18 isotope dating method seems well proven –even RC’s Gavin Schmidt likes it– it would seem this study has a good basis for its claims.”
Otherwise Gavin’s “it” is ambiguous, and could be seen to imply his approval of the study (which so far as shown, he hasn’t commented on it) rather than the underlying methodology.
My own opinion re MWP is that someday we’ll clean up the dating accuracy issues of separate proxies in different regions, and then the MWP will just snap back into view quite distinctly.
I’d really like to see someone undertake, as a peer-reviewed article, the assumption that the dating uncertainties of the proxies is the real problem here, and center the dating of all of them based on the best understanding of when the MWP actually happened.
Otherwise, the dating uncertainty problems of the various proxies “flatten out the sine wave” inherently.
And in related news:
http://www.prnewswire.com/news-releases/climategate-figure-threatens-lawsuit-over-satirical-youtube-video-hide-the-decline—no-cap-and-trade-coalition-says-bring-it-on-91591369.html
A warm anomaly in Indonesian waters might suggest La Nina like conditions (as would profound drought in the western USA). La Nina are usually linked to cool global anomalies. To demonstrate a globally warm MWP, you need, as a minimum, to find proxies from places expected to be cool in La Nina and show that they are average or warm.
The curve is similar to the data from Newton et al (2007) “Indo-Pacific Warm Pool SST Reconstruction (1004 to 1840)”:
http://i34.tinypic.com/2wg7hxy.jpg
Except the Newton curve has a blip in 1463:
http://i35.tinypic.com/11rb3ae.jpg
Those are from my post on SST (paleoclimatological) reconstructions:
http://bobtisdale.blogspot.com/2008/07/sst-reconstructions.html
Or are there “good proxies” and “bad proxies”???
Surely.
Stephen Wilde (13:40:39) : You asked, “Are there any climate changes that cannot be explained by a simple cyclical oscillation of all the air circulation systems latitudinally ?”
ENSO, AMO. The apparent 80- to 100-year cycle in the Southern Ocean:
http://i39.tinypic.com/m7wf7t.jpg
“MrX (12:34:53) :
… I wouldn’t bring plate tectonics into this. It’s a very whacky idea that gained prominence because the older theory couldn’t explain the mechanism. Plate tectonics has changed explanations countless times on its own mechanics and will change again. If you look at the geometry, PT is physically impossible for long distances. …”
Sorry buddy your in a 1950’s time warp. This was the argument in the 50’s and early 60’s when I went to university geology classes. Plate tectonics is proven beyond on all reasonable doubt since then by all the evidence.
MrX (12:34:53) :
“I wouldn’t bring plate tectonics into this. It’s a very whacky idea …”
————
Reply: I agree with Jimmy Haigh’s request for a better theory, MrX. Plate tectonics might be a very whacky (sic) idea, but I’m finding too much evidence to just toss it out unless you’ve got something much more credible than the theory we’re currently using.
Any references? We’re open-minded around here and you won’t get yelled at if what you’ve got is any good.
For those interested here are some more information and papers showing MWP being a global phenomenon.
http://www.cfa.harvard.edu/news/archive/pr0310.html
http://www.co2science.org/data/mwp/mwpp.php
http://uanews.org/node/30720
http://joannenova.com.au/2009/12/fraudulent-hockey-sticks-and-hidden-data/
http://translate.google.com/translate?hl=de&sl=de&tl=en&u=http%3A%2F%2Fwww.science-skeptical.de%2Fblog%2Fbeispiellose-erwarmung-oder-beispiellose-datenmanipulation%2F001195%2F
Bonehead (13:13:20)
There is a huge and compelling literature on the calculation of past sea surface temperatures. This includes thousands of sudies from thousands of marine drill cores and a variety of methods for estimating past water temperatures. The Mg/Ca ratio in planktonic foraminifera shells is one of these methods. It has been cross correlated with several other methods of temperature estimation from foraminifera. It has been checked in the lab by culturing the wee beasties at different temperatures. It has been checked in the field by sampling mordern waters of varying depth, latitude, longitude, temperature, clarity etc. It is also backed by some seriously detailed geochemistry. The effect has been studied extensively in foraminifera. It has also been studied extensively in coral.
The ratio of Mg to Ca in calcite which is secreted during shell production is dependant to a large extent on the temperature of the environment that the organism inhabits. There are some slight variations in the curve for this ratio between different foraminiferal species. This is why the authors of this study concentrated on a single species.
The method has been shown to work in samples from many sites going back hundreds of thousands of years. Now it is being applied with scalpal-like precision to very young sediments. In the future we can expect many more results rather like the those referenced in this article.
If anybody cared to read the paper, they would soon realise that the temperature reconstruction is based on Mg/Ca ratios, not d18O. The latter is used to reconstruct the hydrography.
It’s not a question of good and bad proxies it’s a question of cherry-picking. See Briffa and Mann. Even without proxies historical accounts tell us it was global.
Richard Telford (14:18:05) :
A warm anomaly in Indonesian waters might suggest La Nina like conditions (as would profound drought in the western USA). La Nina are usually linked to cool global anomalies. To demonstrate a globally warm MWP, you need, as a minimum, to find proxies from places expected to be cool in La Nina and show that they are average or warm.
________________________________
How about farming in Greenland?
It’s also worth remembering that during the overall cooling shown by the graph, hundreds of ice-core CO2 measurements show atmospheric concentration rising from less than 280 ppm to more than 310 ppm. Obviously, CO2 causes Global Cooling.
MrX “Also, subduction doesn’t exist on other planets. ”
And the sample size is, what, one other planet?
Two?
For what it’s worth, computer modeling indicates that rocky planets somewhat larger than Earth will have subduction, and hence plate techtonics, even without oceans. For Earth, the oceans are necessary, which explains why Venus shows no signs of it. Of course, what we know of Venus’s surface is limited to radar surveys and short lived probes. Another requirement is a molten mantle.
Mars, in its distant and very wet past, before its core cooled off, may have had subduction and plate techtonics, the debate is still open.
The problem with the MVP and the LIA is that they falsify the current generation of climate models. None of the modelers have the foggiest idea of what caused either, nor how to code them in. However, all of the models are easily tuned to match the hockey stick even with wildly different forcings and feedbacks, just vary the tuning parameters until you get a match. They just can’t predict the MWP or LIA from any currently know scientific principles. In order to validate the models they are left with only two options, either figure out how to include the MWP and LIA into the models, or remove the MWP and LIA from history, which they have been trying to do for the last 20 years or so.
Neither the MWP nor the LIA will be accepted by the ‘True Believers’ in the climate science community until they can figure out how to model them.
Richard Telford (14:18:05),
Here is an interactive map showing the Medieval Warm Period around the globe: click
The MWP was world wide. Which shows that the current climate is normal, and nothing unusual is happening. Furthermore, the Greek optimum prior to both the MWP and the SUV was even warmer.
“MrX (12:34:53) :
Also, subduction doesn’t exist on other planets.”
There is no part of the surface of Venus older than 600 million years.
“DG: ………… The biggest surprise of Magellan was that the surface seems like it’s all the same age. That’s what I’m calling the second great transition. Something changed on Venus 600 or 700 million years ago to make the surface all the same age.
If you use the word catastrophic it rubs some people the wrong way, but something dramatic happened on Venus which wiped out almost all signs of an older surface. The planet got re-paved, basically, 600 or 700 million years ago.
AM: Did some huge impact melt the surface? Or was it the last gasp of volcanic activity?
DG: Clearly, whatever this second great transition was, it involved massive amounts of volcanism. You can see these flows that appear to be flood basalts all over, covering 80 percent of the planet. The remarkable thing is that they seem to be all the same age. The crater density is relatively uniform and random around the planet. So the planet seems to have been flooded with basaltic lavas in a geologically short period of time, simultaneously around the planet.”
http://www.astrobio.net/interview/1137/venus-hothouse-planet
I suspect that is why Venus has such a dense atmosphere and is so damned hot.
Oppo archives her data too. http://www.ncdc.noaa.gov/paleo/pubs/oppo2009/oppo2009.html
Of most importance is the accuracy of the downcore dating. Unfortunately the full-article is behind the Nature paywall so this means a trip to the library.
What we need are well-dated series sampled from the globe that show the MWP happened AT THE SAME TIME around the globe. Otherwise, it can’t be said that the GLOBAL temperature was hotter at that time than before and after. After all, we all know the perils of averaging different proxies together!
Richard,
That’s an amazing map. Thanks for the link!