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.
One problem with calling the MWP “local” is that it is fairly impossible to create a weather map that can loop a warm jet stream up that far north, and then have it come back south over the rest of the northern hemisphere.
This past winter’s record-setting AO created a blocking pattern which could warm Greenland, but not northern Europe, which (as we all know) was very cold.
To have the “local” MWP, which Alarmists suggest existed, you need both Greenland and Europe warm, but Asia cool. The jet would have to be amazingly lop-sided, like a beret stylishly tilted to one side of a head. Basically a huge trough would have to lock itself in place, and not budge for a hundred years, even to thaw the Vikings fields in Greenland.
It is great fun to play around with the Gulf Stream, and to try to create fantastic weather maps. The problem is that most maps that I have created are incredibly unstable. They wouldn’t last a month, let alone a century.
I am really interested to see the map Alarmists use, which makes the MWP manage to be “local.”
Too bad Richard won’t benefit from the map. But others will, and it was posted for them ☺
Caleb (17:49:39),
Right about the MWP being global. It seems there would be a violation of the 2nd Law if one part of the globe stayed significantly warmer than the rest of the planet, for hundreds of years.
The jet stream acts to even out temperatures along the same general latitudes. But the alarmist crowd doesn’t care about thermodynamics, they want to get rid of the MWP completely: click
But that wouldn’t work even if they could pull it off, because 2,000 years before the MWP there was the Minoan climate optimum, which was much warmer than the MWP: click
The current climate is just fine. Could be a little more pleasantly warm. But history tells us that’s controlled by factors beyond the ability of humans – or CO2 – to influence.
… personally I will take any continuous line of proxy data which isn’t stupified (by combining it with other sources or data gathered by different methodologies) … rather than present temperature data sets. The temperature data sets are so compromised by bad methodology I personally couldn’t trust any of it. Unless we say ‘station a’ which hasn’t had any instrumentation changed and has been calibrated and maintained the same way for ‘x years’ shows this trend over this period of time. ‘station a’ however, tells me nothing about ‘station b’ or the aggregate of stations and the aggregate is meaningless.
Great map! Thanks!
/Mr Lynn
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.”
All of the geologists that I know subscribe to standard plate tectonics theory. All of the geophysicists that I know feel that the continents are fairly fixed in place. I can’t say that I know enough (in numbers) of geologists and geophysicists to say that it is a fair representation of the two fields. There are definitely some problems with the mechanism of plate tectonics, but you could say that about the theories of how the solar system formed, also. And in science, you don’t have to have a “better” theory before criticizing someone else’s theory. Sometimes we just really don’t know why things are the way they are.
The real importance of this study is that it is reconstructing ocean temps rather Northern Hemisphere atmospheric temps. If we calculate the total accumulated joules during the MWP in the oceans vs the atmosphere one will not make a significant digit of the other. Why are the climate scientists not trying to find the missing heat in the MWP? Well it looks like its not missing.
@Madman (13:03:14) : “Do you think we could get a key or legend describing the different coloured lines in the graph??”
Here is the entire paper. (You need a sub to get the Nature copy, but I found this.)
https://darchive.mblwhoilibrary.org/bitstream/handle/1912/3188/ppnature08233_with_fig%26supple.pdf?sequence=1
@Duster (13:46:57) :
Good response to a silly comment.
@Janice (18:47:23) :
“…All of the geologists that I know subscribe to standard plate tectonics theory. All of the geophysicists that I know feel that the continents are fairly fixed in place….”
The great battles over the validity of plate tectonics were basically settled in the ’70s. No other theory explains so much about the features of the earth. But the earth doesn’t expose all its secrets, and it takes a long time for most geologic processes to work, so in some cases we don’t have good explanations as to why things happen.
As to the continents being fixed in place, I’m not sure what you’re saying. The continents are part of crustal plates that move about, albeit at rates of a few centimeters a year, top speed. However, the continents are essentially immune, due to their low density, from being subducted. Subduction is a function of density, and old, cold, dense oceanic crust (essentially basaltic lavas and ultramafic intrusives) finally sinks into the upper mantle material, dragging with it pieces of sedimentary prisms which form at the trenches that demarcate subduction zones.
Density differences have a great deal to do with many geologic phenomena, and with some oceanic and atmospheric phenomena, too.
PGosselin thanks for that. Every skeptic/doubter/questionaire should keep this link for when told “show us ONE peer reviewed papers”! from the AGW’s:
http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html
Bob Tisdale (14:25:01)
I don’t see how that helps.
Where is the data about the global net latitudinal position of, say, the mid latitude jet streams (beyond normal seasonal variation) from MWP to LIA to date ?
The information we do have clearly supports the observation that the jets move poleward in warming spells and equatorward in cooling spells on a cycle of 1000 years or more with lesser perturbations on shorter time scales.
Extend that principle to the positions of all the air circulation systems and I know of no climate shift that does not fit.
Can you overlay the air circulation positional data on that graph ?
The MWP should have never been called into question as there has been suficient properly-validated scientific evidence from disparate parts of the globe of the MWP being a global event around for some years. I have just skim-read studies from five widely-separated sites in New Zealand which all confirm the MWP, but that the MWP was warmer than the current Warming Period.
The arrogance and deception of Mann and the rest of the Hockey Team is staggering in its sheer efrontery.
I make it that 8 out of the 11 coldest winters on CET between 1695 and 1814, within 2 to 4 months of the cold episode, have well above average temperatures . I interpret this as the solar signal being very dynamic, and changing dramatically at a weekly or even daily level. Thus a cold winter for the Northern Hemisphere, will be a cooler wetter summer for the Southern Hemisphere, and the cold event will only show up well in one Hemisphere.
The sharp temperature drop in mid July 2009 (which I did forecast), dropped N.H. temperature just a little, but the S.H. was very cold, with many people dead from cold in Peru and elsewhere in South America.
From this view point, I equate Dalton and Maunder type episodes to be changes in the ratio and severity , of short term spikes and notches in the solar signal. Periods when stronger negative temperature features prevail, such as the LIA, may show up generally in both Hemispheres, but year by year, there should be marked differences between Hemispheres.
Ulric Lyons (03:16:29)
Could I ask youto be more specific about the proposed mechanism by which solar variability has it’s proposed effect.
Leif is dismissive of variability in TSI and I tend to accept that.
I have suggested an alternative mechanism which Leif does not accept. Others have suggested ozone related changes in chemical composition and Leif goes with that up to a point.
Can you resolve that aspect ?
I try to square the circle by proposing a much more powerful oceanic influence which sometimes opposes and sometimes suuplements any solar effect. I don’t see how your narrative can fit observations without including another factor such as the oceans except perhaps in the very short term i.e. within the period of a single El Nino or La Nina event. Beyond those timescales the match between solar surface activity and global temperature trends is poor without a variable second force.
Within such short timescales one can get apparent matches between solar surface activity and Earth’s weather (but not really climate) but mostly I see any successes as mere chance combined with rather broad descriptions with a lot of latitude as to scale timing and location. A little like the fortune teller approach in fact.
@Stephan (01:25:54) :
PGosselin thanks for that. Every skeptic/doubter/questionaire should keep this link for when told “show us ONE peer reviewed papers”! from the AGW’s:
http://www.populartechnology.net/2009/10/peer-reviewed-papers-supporting.html
There missing AGW will cause more volcanoes due to melting glaciers from that list and this has been pointed out many, many times Peer-reviewed papers where bedunked after the IPCC got hold of them.
The wise person, when confronted with evidence to the contrary, admits their mistake. Scientists have no difficulty admitting their mistakes, it goes with the territory, it’s part of the job; $cientists have great difficulty admitting their mistakes for it costs them dearly and they may have to actually start working for a living.
A Scientist is no fool!
A $cientist is a fool!
more tree rings
The scientists found the years from 800 to 1300, known as the Medieval Warm Period, had the most frequent fires in the 3,000 years studied. Other research has found that the period from 800 to 1300 was warm and dry.
“What’s not so well known about the Medieval Warm Period is how warm it was in the western U.S.,” Swetnam said. “This is one line of evidence that it was very fiery on the western slopes of the Sierra Nevada
http://www.sciencedaily.com/releases/2010/03/100318093300.htm
Stephen Wilde (05:56:13) : Since only recently we have the instruments to “see” all the radiation spectrum, so it is quite hard for the great majority of astronomers and astrophysicists to get rid of what I call the “flintstones´ universe” conception, a paradigm we all were tought as composed of rounded stones (planets) and balls of fire (stars). It takes several generations to change a paradigm. Newton was not so closed minded as he, intuitively, studied the light spectrum, however all what the world inherited from him was the image of an apple falling from a tree, and thus many generations focused on the apple and, as Newton himself, forgot the tree above!
“Stephen Wilde (05:56:13) :
Ulric Lyons (03:16:29)
Could I ask youto be more specific about the proposed mechanism by which solar variability has it’s proposed effect.”
There is a very good relationship between higher speed solar wind streams from coronal holes, and positive temperature, in most instances. This why temperature changes also relate to geomagnetic activity.
http://www.solen.info/solar/coronal_holes.html
Plasma at the bowshock of the magnetosphere reaches temperatures similar to those found in the corona of the Sun. What happens to this heat?
New sunspot activity giving strong enough flares to raise the solar wind velocity appreciably will also have an effect.
That is a great map, but note in several cases the dates don’t line up as well as you’d need to prove the MWP conclusively. Now, there are two possibilities –one is that it was a rolling regional phenomenon. That one strikes me as pretty unlikely. Or, the other is that the inherent uncertainties in dating the proxies is the problem.
Ulric Lyons (08:09:05)
Ok. Solar wind speed has a direct influence on surface temperatures.
Can you be more specific about how variations in solar windspeed feed into thermal effects on ocean, troposphere and stratosphere so as to affect the size and positions of the air circulation systems and thereby affect the weather or the climate ?
Can you show effects on the 1000 year cycling from MWP to LIA to date or just on short term weather phenomena or on many timescales ?
Are there any charts showing a correlation ?
Ulric Lyons (08:09:05) : This is secret!, it has been forbidden by the Holy Inquisition, in other posts, but, anyway you can see it at your own risk:
http://www.vukcevic.talktalk.net/GeoMagField.gif
Stephen Wilde (08:52:06) :
I am not shure about defining the mechanisms that well, but I do have a very good handle on what is primarally driving it as you might have noticed with my temperature forecasts on your section of climaterealists.com. Weather records for the UK during the colder sections of the LIA report a southerly displacement of the jet stream. Lattitudinal changes of the jet stream can be seen at weelky/monthly scale with changes in solar output. Changes in vorticity and “snakyness” of the jet stream correlate well to Piers`s SWIP`s. I myself am waiting for more observational data from SDO and more investigation into what is happening at the bowshock before making up my mind as to what is occurring at the thermal level. I am though quite surprised how fast Ocean temperaures can actually change, as in the El Nino region. Here is my forecast from December 2007;
“October 2008 should see ocean warming, but unlikely to be a full El Nino, July 2009 onwards should warm oceans enough to trigger one, looking moderate in strength”.
On your last points, the princliples I have discovered essentially cover any timescale. MWP and LIA are part of an event series, with bits of cold and hot weather through both of them. These bits of weather summed become climate. I can confidently say I cand demonstate the cause of Heinrich events (4627yr), the c.1150yr cycle (MWP to LIA to present) down to weekly/monthly changes from the same “rules”.
I am currently testing and improving the theory by forecasting, prior to publication.
Has anybody here actually read the paper ?
It’s rather hard to find pre-prints of published papers online:
https://darchive.mblwhoilibrary.org/bitstream/handle/1912/3188/ppnature08233_with_fig%26supple.pdf?sequence=1
Look at the graph at the top of this page:
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.
What they left out from the paper were the lines representing the 1997-2007 Mean Annual SST (Sea Surface Temperatures) – which are already cooler than current SST’s – and the JAS (July August September) line, which is cooler than the annual mean. This Indonesian site, Makassar Strait, is south of the Equator, so JAS is winter there.
Look at Figure 2a in the paper – the one preceding the modified 2b shown above. The plankton shell data tracks the JAS temperature well from 1850 to 1940, then jumps up to track the Mean Annual Temperature curve.
Huh.
Now, that’s inconvenient.
As the paper says:
Given the evidence that G. ruber tends to record near mean annual SSTs during warm intervals of the last 150 years (Fig. 2a),
and
If, on the other hand, G. ruber calcified preferentially during the JAS upwelling season throughout the study interval,
Those uncooperative little plankton bounced around during the period in which they had both plankton and instrumental temperature data (1850-1980), tracking either the mean annual SST’s, or the coldest ones (JAS). This is a difference of about 0.8 °C.
So, what about the -300 AD to 1980 period ? Any bouncing around there? Certainly. So that whole LIA section in Figure 2b should be shifted up about 0.8 °C, if you want to compare annual mean SST to annual mean SST for the whole graph.
Finally, note that the blue line in Figure 2a (see the paper) ends before 1980.
This is the blue line in the Figure in this thread (above), representing “the Current Warm Period”.
The blue line is from 31MC, the red line is from MD60 – see where they overlap ? The red line is about 0.8 °C higher SST. See Figure 1 for the locations of these two cores – about 50 miles apart, in the Makassar Strait. That makes the entire red line “MWP” temperatures suspect – are they shifted 0.8 °C higher too ?
Now look at global temperatures since 1980 – they are up about 0.6 °C
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
If the blue line 31MC SST values were not shifted down 0.8 °C relative to the red line MD60 core values (which should both be measuring the same SST), and the final 30 years of temperature data were added to the blue line, then the current SST would be 1.0 °C warmer than in the MWP.
I guess that’s “within error” as the paper’s authors claimed:
Reconstructed SST was, however, within error of modern values during the Medieval Warm Period from about AD 1000 to AD 1250,
The error bars are pretty large – you don’t know if the plankton are tracking JAS or mean annual SST, and the calculated SST varies by about 0.8 °C for two different cores about 50 miles apart. Clearly they need to look at more cores, and have more “overlapping in time” core comparisons.
Stephen Wilde (05:56:13) :
Leif is dismissive of variability in TSI and I tend to accept that.
Stephen, Leif is pretty much on his own in this regard, most scientists in this area do not go along with Leif’s “solar floor”.
We tend to only get one perspective most of the time on WUWT.