The graphic above is not from this paper/abstract, nor even the same time frame, but is from this one: A High-Resolution Absolute-Dated Late Pleistocene Monsoon Record from Hulu Cave, China I posted it because it seems relevant to the discussion of the paper below. I’m not an expert on cave and isotope dating, but I thought I’d provide a mix of resources to go along.
Here is some interesting reading. From the abstract, it suggests a correlation between monsoon and medieval warm period etc. But as we often see in papers that touch the edge of skepticism, there’s the obligatory line: “The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.”
I wonder. Here is another paper along the same lines, Holocene variability of the East Asian summer monsoon from Chinese cave records: a re-assessment sans the AGW suggestion.
Here is the link to the abstract below. Unfortunately, the full paper is behind the green wall of the AAA$, even though much of the research is from public institutions. Personally I think charging for access to such papers is flat wrong.
A Test of Climate, Sun, and Culture Relationships from an 1810-Year Chinese Cave Record
Pingzhong Zhang,1 Hai Cheng,2* R. Lawrence Edwards,2 Fahu Chen,1 Yongjin Wang,3 Xunlin Yang,1 Jian Liu,4 Ming Tan,5 Xianfeng Wang,2 Jinghua Liu,1 Chunlei An,1 Zhibo Dai,1 Jing Zhou,1 Dezhong Zhang,1 Jihong Jia,1 Liya Jin,1 Kathleen R. Johnson6
A record from Wanxiang Cave, China, characterizes Asian Monsoon (AM) history over the past 1810 years. The summer monsoon correlates with solar variability, Northern Hemisphere and Chinese temperature, Alpine glacial retreat, and Chinese cultural changes. It was generally strong during Europe’s Medieval Warm Period and weak during Europe’s Little Ice Age, as well as during the final decades of the Tang, Yuan, and Ming Dynasties, all times that were characterized by popular unrest. It was strong during the first several decades of the Northern Song Dynasty, a period of increased rice cultivation and dramatic population increase. The sign of the correlation between the AM and temperature switches around 1960, suggesting that anthropogenic forcing superseded natural forcing as the major driver of AM changes in the late 20th century.
1 Key Laboratory of Western China’s Environmental Systems (Ministry of Education), College of Earth and Environment Sciences, Lanzhou University, Lanzhou 730000, China.
2 Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455, USA.
3 College of Geography Science, Nanjing Normal University, Nanjing 210097, China.
4 Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
5 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
6 Department of Earth System Science, University of California, Irvine, Irvine, CA 92697, USA.
hat tip to Dave Hagen
crosspatch (13:46:01) :
And think of all the moisture released to the atmosphere at this time. I personally believe that many alpine ice sheets are 10k to 12k years old (Kilimanjaro) because they formed when the continental glaciers retreated.
PearlandAggie (17:02:49) :
does it look to you guys like there might be another SC23 spot forming just south of the solar equator?
It is dying. It was a SC23 spot on the backside of the Sun
Joel Shore said:
The contrived disappearance of the MWP isn’t just a discredited Michael Mann talking point; if the MWP occurred, then the entire AGW edifice comes crashing down.
That’s why the alarmists can not admit its existence.
Per Strandberg (18:00:43) :
Also it can’t be the Sun today, as the TSI haven’t varied much since 1960. Apparently it varied much more during the warming during the early part of the 20 th century. It must do that to fit the AGW agenda, so no proof is necessary.
And in addition the TSI didn’t vary much more during the early part of the 20th century: http://www.leif.org/research/GC31B-0351-F2007.pdf
[…] But it was not just me. This morning, Anthony Watts posted the following in Watts Up With That? “A Test of Climate, Sun, and Culture Relationships from an 1810-Year Chinese Cave Record”. […]
I have a question, no doubt already answered but as I am a noob in these things perhaps you will forgive me.
On the SD graph, the Northern Hemisphere temps appear remarkably flat in comparison with those attributed to earlier centuries. Whats up with that?
Errr re above – flat in the 20th Century. Oh fof an edit button 😉
Robert Morris. you are not the only one to have noticed this. Apart from Mannian School manipulations (the Hockey Stick, etc), many reconstructions show the 20th century’s climate to be remarkably stable (uniform) compared to earlier centuries.
Which BTW, makes the last 30 or 40 years unusual on a century scale (ie the 20th century) but not on a millenium scale.
This reconstruction shows the very abrupt cooling around 1600 or a little earlier, which other reconstructions show as -2C to -3C in as little as a decade. Were such a cooling to occur today it would be an unimaginable worldwide disaster with crop failures and famine almost everywhere.
The original paper (supplement actually) shows that the oxygen stable isotope fraction (of the CO3 in the calcite in the cave stalagmite) has a good correlation with both temperature and precipitation in the timeframe 1960-2000 and extrapolates this backwards through the seasonal layers of calcite.
The Science Daily article (link posted by Paul (13:57:17) above) is a good summary of findings, but shows a graph that is a hybrid of several in the paper.
As noted above the NH temperature is quite variable – more than Hockey Stick graphs. it is from another paleo reconstruction from mixed sources (A. Moberg, et al., Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data. Nature 433, 613 (2005) – link with graphic (note link to original data below abstract!)http://www.ncdc.noaa.gov/paleo/pubs/moberg2005/moberg2005.html
This in itself is notable for the absence of hockey stickiness. Both the cave data and the other proxy data agree quite well from 750AD to present and suggest Medieval Warm Period temperatures similar to present. The cave data paper does not report a temperature anomaly range; Moberg et al’s plot is +0.1 to -0.9 (deg C) approx by eye.
In the Science paper, in addition to this graph, two other NH temperature series are used, one of which is Mann & Jones, Geophys. Res. Lett. 30, 1820
(2003) – a hockey stick. The range of this anomaly is -0.5 to -0.1 deg. C for most of the construct and -0.1 to +0.1 since about 1900.
They also correlate the data (as a proxy for rainfall/temperature) with Solar irradiance from 10Be and 14C records (about which I am sure Leif would have some criticism) and analyse the isotope data with a univariate spectral analysis ( in on-line supplement) finding 4 periodicities including a 10.5-year period corresponding to the Schwabe cycle of sunspot variability.
I am not sure if you are aware of this, but the following web site has summaries and citations of several hundred studies which show the global reach of MWP and LIA.
http://co2science.org/data/mwp/mwpp.php
Pls patronize the site. They do a weekly update of a new peeer reviewed article which demonstrates the existence of MWP and LIA
Interesting. Some very recent evidence suggests the Younger Dryas cooling (& NAmerican extinctions) could have been caused by a comet/meteor strike instead of the old theory of ocean current changes — look here:
http://www.bitsofnews.com/content/view/5737/
If so, the impact could’ve caused over a thousand yrs of iceage-like climate. One would wonder how the direct effects could last that long — atmospheric debris would have cleared out in mere decades or less. Perhaps long-lasting ocean current shifts were caused by the impact.
Well, here is the thing for me … for the past 2 million years or so ice age is the normal condition. Warm interglacial periods like we are in now are the “odd” condition. Glacial periods last for 100K years. Interglacial periods about 10K years. We are nearing the end of the average interglacial duration (actually past it). So I can’t really buy the notion that something that happens once every 100K years triggers an ice age. Rather, something that happens once every 100K years brings us out of one temporarily.
I managed to find an add-on for NASA World Wind that allows me to adjust sea levels. When sea levels were at their minimum things were much different in the Caribbean. There was a land mass between Cuba and Florida. There was much more land off the coast of Florida. There was a huge land mass in the Atlantic Southeast of Newfoundland larger than Nova Scotia.
I am fairly convinced that while Earth’s orbital cycles appear to go in 100K year cycles, they don’t result in causing an ice age. Again, ice age is currently the NORMAL phase. Interglacial is the oddity. I don’t believe that conditions were such 12K years ago to bring us out. My gut says it is due to us living near a variable star. I suspect that we go into a deep solar minimum that results in an increase in albedo that acts as hysteresis. We go into a deep minimum, ice builds up, it causes albedo to increase and the sun goes into another minimum before Earth has completely recovered from the first … and bingo … we start the spiral downward in temperature until we have a combination of both favorable orbital dynamics AND an active sun.