China’s 2,000 Year Temperature History
While Mann claims his hockey stick science to be “vindicated”, we have this from World Climate Report, a new peer reviewed study that illustrates that the current warm period we live in is neither unique nor unprecedented. They also manage to point out the key issue, the uncertainty of proxies such as used by Mann et al. – Anthony
We constantly hear that the warmest years on record have all occurred in the most recent decades, and of course, we are led to believe this must be a result of the ongoing buildup of greenhouse gases. In most places, we have approximately 100 years of reliable temperature records, and we wonder if the warmth of the most recent decades is unusual, part of some cyclical behavior of the climate system, or a warm-up on the heels of a cold period at the beginning of the record. A recent article in Geophysical Research Letters has an intriguing title suggesting a 2,000 year temperature record now exists for China – we definitely wanted to see these results of this one.
The article was authored by six scientists with the Chinese Academy of Sciences in Beijing, the State University of New York at Albany, and Germany’s Justus-Liebig University in Giessen; the research was funded by the Chinese Academy of Sciences, National Natural Science Foundation of China, and the United States Department of Energy. In their abstract, Ge et al. tell us “The analysis also indicates that the warming during the 10–14th centuries in some regions might be comparable in magnitude to the warming of the last few decades of the 20th century.” From the outset, we knew we would welcome the results from any long-term reconstruction of regional temperatures.
The authors begin noting that “The knowledge of past climate can improve our understanding of natural climate variability and also help address the question of whether modern climate change is unprecedented in a long-term context.” We agree! Ge et al. explain that:
“Over the recent past, regional proxy temperature series with lengths of 500–2000 years from China have been reconstructed using tree rings with 1–3 year temporal resolution, annually resolved stalagmites, decadally resolved ice-core information, historical documents with temporal resolution of 10–30 years, and lake sediments resolving decadal to century time scales.”
However, the authors caution “these published proxy-based reconstructions are subject to uncertainties mainly due to dating, proxy interpretation to climatic parameters, spatial representation, calibration of proxy data during the reconstruction procedure, and available sample numbers.”
Ge et al. used a series of multivariate statistical techniques to combine information from the various proxy methods, and the results included the reconstruction of regional temperatures and an estimate of uncertainty for any given year. They also analyzed temperature records from throughout China over the 1961 to 2007 period and established five major climate divisions in the country (Figure 1).
Figure 1. Types, lengths, and locations of proxy temperature series and observation used in the Ge et al. study. The five climate regions were based on a “factor analysis” of the 1961–2007 instrumental measurements. Grey shading indicates elevation (from Ge et al., 2010).
The bottom line for this one can be found in our Figure 2 that shows the centennially-smoothed temperature reconstruction for the five regions of China. With respect to the Northeast, Ge et al. comment “During the last 500 years, apparent climate fluctuations were experienced, including two cold phases from the 1470s to the 1710s and the 1790s to the 1860s, two warm phases from the 1720s to the 1780s, and after the 1870s. The temperature variations prior to the 1500s show two anomalous warm peaks, around 300 and between approximately 1100 and 1200, that exceed the warm level of the last decades of the 20th century.” The plot for the Northeast shows warming in the 20th century, but it appears largely to be somewhat of a recovery from an unusually cold period from 1800 to 1870. Furthermore, the plot shows that the recent warming is less than warming that has occurred in the past.
Figure 2. Five regionally coherent temperature reconstructions with 100-year resolution; the dashed line is the part with fewer series used; and the solid line is the mean value. The shaded areas are the two coldest periods, during the 1620s–1710s and 1800s–1860s (from Ge et al., 2010).
The Central East region also has a 2,000 year reconstruction and Ge et al. state “The 500-year regional coherent temperature series shows temperature amplitude between the coldest and warmest decade of 1.8°C. Three extended warm periods were prevalent in 1470s–1610s, 1700s–1780s, and after 1900s. It is evident that the late 20th century warming stands out during the past 500 years. Considering the past 2000 years, the winter half-year temperature series indicate that the three warm peaks (690s–710s, 1080s–1100s and 1230s–1250s), have comparable high temperatures to the last decades of the 20th century.” No kidding – the plot for the Central East region shows that the warmth of the late 20th century was exceeded several times in the past.
Commenting on the Tibet reconstruction, Ge et al. state “The warming period of twenty decadal time steps between the 600s and 800s is comparable to the late 20th century.” In the Northwest, they note “Comparable warm conditions in the late of 20th century are also found around the decade 1100s.” Unfortunately, no long-term reconstruction was possible for the Southeast region.
In summarizing their work, Ge et al. report :
From Figure 3 [our Figure 2 –eds.] , the warming level in the last decades of the 20th century is
unprecedented compared with the recent 500 years. However, comparing with the temperature variation over the past 2000 years, the warming during the last decades of the 20th century is only apparent in the TB region, where no other comparable warming peak occurred. For the regions of NE and CE, the warming peaks during 900s–1300s are higher than that of the late 20th century, though connected with relatively large uncertainties.
We get the message – the recent warming in at least several regions in China has likely been exceeded in the past millennium or two, the rate of recent warming was not unusual, and the observed warming of the 20th century comes after an exceptionally cold period in the 1800s.
Declaring that anthropogenic greenhouse gas emissions have pushed modern temperature beyond their historical counterparts disregards the lessons of 2,000 years of Chinese temperatures.
Reference:
Ge, Q.-S., J.Y. Zheng, Z.-X. Hao, X.-M. Shao, W.-C. Wang, and J. Luterbacher. 2010. Temperature variation through 2000 years in China: An uncertainty analysis of reconstruction and regional difference. Geophysical Research Letters, 37, L03703, doi:10.1029/2009GL041281.
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KenB: “As a long time observational student of human beings, their behavioural trends and the psychology of crowd behaviour, I have noted that the rather strident “intelligent lay person” who accepted the scientific “consensus” without question, and applied and labeled sceptics with the worst of motives seem to now want to disengage from their version of the “debate” and distance themselves and change the subject, a version of the three wise monkeys now that its becoming clearer that things are not as they were when their “science reigned supreme.”
Last night I got into what turned out to be a very unfortunate “discussion” with a diehard AGW advocate who teaches in the public schools in Baltimore and considers herself a “scientist.” She had just returned from a Smithsonian training program on global warming for teachers. When engaging her I pointed out as a leading remark that Al Gore conceals the fact that temperature is the leading indicator in his CO2/temp. chart. I think she had never wondered about that and was shocked when she got the implication. Thereafter nearly every point I made was countered with “we know that” and the subject was changed. The extent of her ignorance was truly appalling. Not once did she concede a point. I know this is probably not news to most of the readers here, but this truly is a secular religion.
Another paper for the list, thanks Anthony and Pat,
750 Peer-Reviewed Papers Supporting Skepticism of “Man-Made” Global Warming (AGW) Alarm
It has been argued by some here that the “Medieval Warm Period” was only regional and not global, yet I look at current temperature maps of the earth and see some regions that are warm and some regions that are not, so the argument that the current warming period being global (or even hemispherical) doesn’t appear to be valid either. And when one considers that a good portion of the current “warming” is apparently due to instrument siting problems and skewing using homogenization factors, the argument that what we’re supposedly experiencing is unprecedented is very weak indeed.
As time goes by and more anti-warming research is published and as the earth continues to refuse to march to the warmer’s errant modeling, the idea of CO2 being the culprit will become more and more laughable.
Turboblock @ur momisugly 4:50 am is quite right.
Temperature does not seems well correlated in different regions. By year 300 – 400 there is cooling at high altitude (TB) and warming in the NW.
Not even in the 20th Century the five regions seem to agree.
The medieval warm period is not comparable to Europe, there is a short warming in the North ~1100 with a wide oscillation at high altitude.
In a summary, the temperature record is quite different from Europe or South America and among the 5 Chinese regions themselves.
This should require a bit more of attention. If consistent with other records it would show that regional variation is far more important than global averages…. Interesting…
@wren
Quoting from Mann’s 2009 study:
“The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”
At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.
End. Thank You. Good Night.
@ur momisugly Alexander K
We entered the war in 1939, with our growing economic might, without which, Germany would have prevailed on both fronts. It wasn’t immediately apparant that it wasn’t just another of Europe’s wars.
China has issues.
Here is an American geologist that was tortured and sent to jail for 8 years for gathering data.
During Xue’s closed-door trial, which ran over three dates last July and in December, the court document said he defended himself, arguing that the information he gathered “is data that the oil sector in countries around the world make public.”
David Rowley, Xue’s thesis adviser at University of Chicago and a geologist, said that the location and seismic and other data of oil wells is commonly available and could not compromise Chinese security since the government controls access.
“What frightens me most about this is that Xue Feng is, in my experience, a straight-up individual who worked hard, who didn’t push limits, or try to pull a fast one by, but was simply honest and entirely well meaning,” Rowley said in an e-mail. “That’s IHS’s business — acquiring and redistributing data (bases) so he was simply doing his job.”
http://www.foxnews.com/world/2010/07/04/chinese-court-sentences-geologist-tortured-state-security-agents-years-jail-1624851947/?test=latestnews
Now several days a week, the Commie supporting web site toughts the awsomeness of china. They are good, clean and pure. But they also are strict on who says what.
I believe some chinese research gets out there that shows some of our claims to be false. I also accept they may push some untruthfull stuff at the same time.
Where can I read their FOIA???
Well documented “regional” histories serve to collectively show global conditions best. “Scientific” studies such as this may be perfectly researched, analyzed, documented, and presented; in this day and age, however, they may also reflect a “political”, “economic”, or “social” objective (do not ‘assume’ anything) –“trust no one” is probably the best advice. “Cult” and “Political” science is everywhere these days. Go slow, assume nothing. (But it sounds reasonable, doesn’t it?)
I know people get excited about proxies, but unless they are characterized by experimentation then they aren’t that much use.
It’s like this little story:
I own a farm on which I have an apple launching machine. It launches apples into a container 100 yards away. (Now the reason for this is just assumed that that is how it is). It turns out that I need to move the container by 10 feet. So on first glance I need to up the power in the launcher, but I’m not sure I can afford that. So I do some aerodynamical calculations and look up all the current theories and come up with this:
If I polish the apples in a certain way my model tells me that they will actually fly another 50 yards. The polishing is within me budget. This is great as I can reduce the cost of running the launcher. But a little voice in my head is saying hmmm that’s seems a little far fetched, you might want to test that?
So before this I recheck the calculations and theory and it turns out I can reformulate it, and the result is that my model says the apples will only go another 5 yards. Okay I say that seems more reasonable. Its not what I want but its a start, so I make the modifications and start launching apples.
And nothing changes. The apples go the same distance as before, polished or not.
Now as an experimental scientist rather than a theoretical one, I can see the problem here. Psychologically it is easier to accept the model predictions for the latter case because they are just a wee bit different. And being just a little extrapolation I decide to implement change. The former case just seems a bit far fetched so I am much more hesitant.
Well the experimental scientist (and the marketer for that matter) would test BOTH without prejudice. Because both are extrapolations into the unknown. And so we see the same behaviour with models and proxies. Lots of little extrapolations that actually needed to be tested. But because people don’t mind the little extrapolations, soon we have an AGW machine in which every one is convinced. Like the spies always say: The best untruth is 95% truth.
Its just regional … its only weather … the authors are stooges for big oil … 3,000 scientists say otherwise…
This article needs to be retracted or at least corrected. Based on Mann (2009):
“The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”
the only conclusion I can make is that it is highly misleading (right from the title: New ‘Chinese study in GRL disputes the hockey stick conclusions’ through to its conclusions). Whether or not you agree or disagree with Mann’s findings is completely irrelevant. The only way that you can reach the rubbish generalization that the title of this thread purports to offer is by substantially misrepresenting what Mann said.
REPLY: Sorry, you are 10 years off. The “hockey stick” came from MBH98/99 not 2009 -A
Liam, are you serious? Over 31,000 scientist with over 9,000 PHDs dispute your 3,000. The 3,000 is also phantasy.
Chinese sure say:”Global warming tale from occident”
Did I miss the bit in the Ge et al where they construct a northern hemisphere temperature time series?
The title of this article is:
“New Chinese study in GRL disputes the hockey stick conclusions”
Where is you reference that backs up this claim?
The conclusion of MBH 99 is as follows:
“Although NH reconstructions prior to about AD 1400
exhibit expanded uncertainties, several important conclu-
sions are possible, notwithstanding certain caveats. While
warmth early in the millennium approaches mean 20th cen-
tury levels, the late 20th century still appears anomalous:
the 1990s are likely the warmest decade, and 1998 the
warmest year, in at least a millennium. More widespread
high-resolution data which can resolve millennial-scale vari-
ability are needed before more con fident conclusions can be
reached with regard to the spatial and temporal details of
climate change in the past millennium and beyond.”
Ge et al does not say anything about mean Northern Hemisphere temperatures. How exactly does it contradict the MBH99 conclusions? (especially given that MBH explicitly state that more data is needed before they can say anything about regional climate details).
I’m sorry, but if you are going to hold IPCC to certain editorial standards (e.g. “AmazonGate”) then you should at least make an effort to meet those standards yourself. Is this the beginning of “ChinaGate”?
Global or hemispheric values are derived, roughly speaking, by combining the data and working out the mean. If you are assuming that anyone is trying to say there was no MWP, then you are unfamiliar with the science. Discussion centres on the amplitude, not the veracity of medieval warmth.
There were cool and warm regions during the Little Ice Age, too, but the mean value was cooler than the 20th century.
Latimer Alder says:
July 5, 2010 at 7:41 am
@wren
Quoting from Mann’s 2009 study:
“The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”
At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.
End. Thank You. Good Night.
====
If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.
File that one under logical fallacy.
Wren says on July 5, 2010 at 12:28 pm
DirkH says:
“I’d like to remind you that it was mainly the Americans who liberated Germany and helped us establish a stable democracy. Your influence is not lost.”
That is debatable in several respects. Fist of all not one country went to war with the intention of liberating Germany. Britain (and France) went to war with unsuccessful aim of preventing Germany from conquering Poland. The Soviet Union went to war because it was attacked by Germany and some of Germany’s European allies. The United States went to war against Germany because Germany had declared war on the United States immediately after the Japanese attack on Pearl Harbor.
Secondly, while not wishing to down-play the enormous part the Americans played in the war, I think your comments, like Hollywood films and even some serious American historians, try to make the American contribution look even more significant than it was by down-playing the roles of other countries. The war would not have been won without the enormous sacrifices made by the Soviet Union. Nor would it have been won if Britain had not decided to continue the fight in 1940 or if the RAF had lost the Battle of Britain. In addition the British inventions of radar and electronic code breaking machines (the forerunners of modern electronic computers) were also of enormous importance.
Radar, electronic methods of code breaking, preliminary work on the atomic bomb, and penicillin (which prevented tens of thousands of deaths from infected wounds) were all given to the United States by Great Britain, as was the jet engine which Britain could, and should, have developed in the 1930s but unfortunately did not use until the final months of the war.
david says:
July 5, 2010 at 10:08 am
Liam, are you serious? Over 31,000 scientist with over 9,000 PHDs dispute your 3,000. The 3,000 is also phantasy.
====
Not 31,000 climate scientists. Not even 31,000 scientists.
Richard Sharpe says:
July 5, 2010 at 12:43 pm
Wren says on July 5, 2010 at 12:28 pm
Latimer Alder says on July 5, 2010 at 7:41 am
@wren
Quoting from Mann’s 2009 study:
“The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally.”
At which point I see Angels Dancing on the Heads of Pins coming into view and terminal boredom setting in. Game over…slam dunk…the recent warming is not unprecedented…CAGW falls because these climatic conditions have happened before without catastrophe.
End. Thank You. Good Night.
====
If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.
File that one under logical fallacy.
However, that is not the issue under dispute. Some, perhaps most, proponents of AGW claim that the current warming is unprecedented, which they then suggest is evidence that it must be human caused.
Your dishonest attempt to redirect discussion is noted.
=====
Scientists who are proponents of AGW claim that current warming is unprecedented in the history of the world?
That’s news to me. Can you quote some of them?
Barry (July 5, 2010 at 12:25 am)
Nice try. Now match this one
And btw, I looked at that website’s page of “anti-AGW papers debunked” and apart from Gerlich & Tscheuschner (which appears to be suspect), all the papers familiar to readers here (Lindzen, Svensmark, etc) have many supporters here who can debunk all those debunks. I always look hard at the best evidence on both sides to see who practises scientific method for themselves rather than appeal to authority, and can debunk the most thoroughly and still practice courtesy, and when I get to the end of the trail of clues and see who wins out, I have a strong sense for the future of whom I would start off by trusting. You might like to do likewise.
Wren says:
July 5, 2010 at 12:28 pm
“If nature can cause global warming without catastrophe, nature plus man can’t cause catastrophic global warming.”
Nature plus man??? Is man not part of nature? Talk about a logical fallacy! But this makes sense if there’s no evolution and man just showed up one day.
Wren, I’d rather 31,000 scientists of any hue than the political yes men infesting the ranks of the IPCC. Surely even you can recognise that 31,000 is much more of a consensus? 😉
“”barry says:
July 5, 2010 at 12:08 am
This is the temp record for China, not the globe. It’s a small fraction of the northern Hemisphere. One of the key points in most reconstructions of NH millennial temps is that warming happened at different times in different regions,””
Barry, can trees move?
Roy says:
July 5, 2010 at 12:46 pm
I think Ben and DirkH were speaking in the context of 4th July and independence, and bemoaning the fact that their democracy could not give exposure to a truth whereas the Chinese communist system could.
I hope you are very young and not British (i am neither).
The truth, whether you would like to accept it or not, is that the US saved Europe in both the 1st and 2nd World Wars.
God Bless America, and I’m not American.
tim
tim