By comparing today’s Nature paper to earlier versions I found just a few months old, it looks like some blame revisionism occurred after early discussions of this paper at NOAA in May 2012.
Over at Australian Climate Madness, Simon points out the coverage of the ABC for this new paper in Nature. He writes:
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Just as we must get rid of the Medieval Warm Period, the inconvenient Roman Warm Period must also be dealt with, and here’s a novel way of doing it: claim that it was man-made. In a single stroke, the RWP is scrubbed from the list of “natural warmings” that the planet has experienced in recent history, helping the Cause by demonstrating that it too was anthropogenic. The ABC reports:
A period covering the heyday of both the Roman Empire and China’s Han dynasty saw a big rise in greenhouse gases, according to a new study.
The finding challenges the view that human-made climate change only began around 1800.
A record of the atmosphere trapped in Greenland’s ice found the level of heat-trapping methane rose about 2000 years ago and stayed at that higher level for about two centuries.
Methane was probably released during deforestation to clear land for farming and from the use of charcoal as fuel, for instance to smelt metal to make weapons, says lead author Celia Sapart of Utrecht University in the Netherlands.
“Per capita they were already emitting quite a lot in the Roman Empire and Han Dynasty,” she says of the findings by an international team of scientists published today in the journal Nature (link to abstract). (source)
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Only one problem. Versions of this paper and slide presentation by the lead author in mid May 2012 make no mention of the Romans or Han dynasty whatsoever. Here’s the original abstract compared to the current one:
ORIGINAL – May 15th, 2012 at NOAA’s ESRL: (Source: http://www.esrl.noaa.gov/gmd/annualconference/abs.php?refnum=110-120409-A)
Isotope Variations in Atmospheric Methane Over the Last Two Millenia
T. Röckmann1, C. Sapart1, G. Monteil1, M. Prokopiou1, R.V.D. Wal1, P. Sperlich2, J. Kaplan3, K. Krumhardt3, C.V.D. Veen1, S. Houweling1, M. Krol1, T. Blunier2, T. Sowers4 and P. Martinerie5
1Institute for Marine and Atmospheric Research, Utrech University, Utrecht, Netherlands; 303-497-4988, E-mail: t.roeckmann@uu.nl
2Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, København DK-2100, Denmark
3Ecole Polytechnique Federale de Lausanne, Route Cantonale, Switzerland
4Earth and Environmental Systems Institute, Geosciences, Penn State University, University Park, PA 16802
5Laboratoire de Glaciologie et Géophysique de lEnvironement, University of Grenoble, Grenoble, France
Methane (CH4) is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric levels of CH4 have varied on various timescales in the past, but in many cases the causes of these variations are not understood. Analysis of the isotopic composition of CH4 preserved in ice cores provides evidence for the environmental drivers of variations in CH4 mixing ratios, because different sources and sinks affect the isotopic composition of CH4 uniquely. We have analyzed (δ13C) of CH4 in air trapped in Greenland ice cores over the last 2 millennia and find that the carbon isotopic composition underwent pronounced centennial-scale variations between 200 BC and 1600 AD without clear corresponding changes in CH4 mixing ratios. The long-term CH4 increase observed over this period is accompanied by a small overall δ13C decrease. Two-box model calculations suggest that the long-term CH4 increase can only be explained by an increase in emissions from biogenic sources. The centennial-scale variations in isotope ratios must be primarily due to changes in biomass burning, which are correlated with both natural climate variability including the Medieval Climate Anomaly, and with changes in human population, land-use and important events in history.
Now compare that original abstract presented to NOAA to the abstract of the paper in Nature being touted by the press on October 3-4, 2012:
Natural and anthropogenic variations in methane sources during the past two millennia
C. J. Sapart, G. Monteil, M. Prokopiou, R. S. W. van de Wal, J. O. Kaplan, P. Sperlich, K. M. Krumhardt, C. van der Veen, S. Houweling, M. C. Krol, T. Blunier, T. Sowers, P. Martinerie, E. Witrant, D. Dahl-Jensen & T. Röckmann
Nature 490, 85–88 (04 October 2012) doi:10.1038/nature11461
Methane is an important greenhouse gas that is emitted from multiple natural and anthropogenic sources. Atmospheric methane concentrations have varied on a number of timescales in the past, but what has caused these variations is not always well understood1, 2, 3, 4, 5, 6, 7, 8. The different sources and sinks of methane have specific isotopic signatures, and the isotopic composition of methane can therefore help to identify the environmental drivers of variations in atmospheric methane concentrations9. Here we present high-resolution carbon isotope data (δ13C content) for methane from two ice cores from Greenland for the past two millennia. We find that the δ13C content underwent pronounced centennial-scale variations between 100 bc and ad 1600. With the help of two-box model calculations, we show that the centennial-scale variations in isotope ratios can be attributed to changes in pyrogenic and biogenic sources. We find correlations between these source changes and both natural climate variability—such as the Medieval Climate Anomaly and the Little Ice Age—and changes in human population and land use, such as the decline of the Roman empire and the Han dynasty, and the population expansion during the medieval period.
Note that the two abstracts start out identically (highlighted in blue), and have similar language throughout presenting the isotope data, but that the Nature abstract has that added part about Roman empire and the Han dynasty.
In this slideshow presentation of the paper, http://www.esrl.noaa.gov/gmd/annualconference/slides/110-120409-A.pdf this graph from page 5 is quite telling:
As Simon points out on his blog:
The population, as the article goes on to say, was about 300 million, barely 4% of what it it today, and without any industrialisation apart from burning charcoal. I will leave it to you to consider the likelihood of such a tiny agrarian population having a significant effect on the climate.
The ABC’s coverage is similarly disingenuous. I’m not going to pay thirty bucks for the full article in Nature (if anyone has access, I would be grateful for a PDF), but eyeballing the tiny graphics published with the abstract (see above) seems to indicate that centennial scale changes in CH4 mixing ratio in the Roman period were in the order of a 20-40 parts per billion (that’s billion with a b). How the ABC can call this a “big rise in greenhouse gases” is unfortunately yet more evidence of agenda-driven journalism. It’s a tiny fraction compared with the industrial rise in CH4, which took mixing ratios to over 1800 ppb, yet the paper claims it is responsible for the significant warming that occurred around the time of the Roman empire?
The graph of CH4 compared to land use change seems like a good case of correlation:
But as we so often learn, when it comes to correlation, that does not always imply causation. Check out this multipanel graph from page 11 of the slide show:
Note graph “f” in red, which are temperature reconstructions from Moberg et al., 2005, Ljungquist et al., 2011, and try to find a correlation with Ch4 emissions in graph “b”.
From my view, there certainly doesn’t seem to be one that holds past 1000AD, when temperature started going down, but world population and land use increased. Likewise, correlation with transformed charcoal in “c” is weak as well.
The conclusion page 13 from the presentation seem pretty wishy-washy, especially the last point, where no specific blame is placed:
Conclusions
•Pronounced centennial-scale δ13C(CH4 ) variability in pre- industrial period
•Highly likely caused by changes in pyrogenic sources
•Correlation with NH charcoal index and anthropogenic land use rate of change
•Long term CH4 rise due to biogenic sources, and correlates well with land use data
•Both natural variability and anthropogenic activities may have influenced the CH4 budget in the pre-industrial period
The claim about the Romans and Han Dynasty seems quite a stretch when you actually look at the data/graphs. But as you can see in the ABC article, they don’t dare show you those things lest you draw conclusions of your own that don’t fit their narrative.
This might help you understand the motivation to start blaming the Romans and the Asians:
Atmospheric Physics and Chemistry Group
Dr Celia Julia Sapart
Master in “Climate Change”, University of East Anglia, Norwich (UEA), UK, 2006-2007
http://www.projects.science.uu.nl/atmosphereclimate/celia.php
Perhaps she got “Jonesed” into adding the part about the Romans and Han dynasty?
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Whole thing is a bit of a joke.
Natural causes and natural causes.
There is a relatively good instrumental record for the CET 1650-1750:
http://www.vukcevic.talktalk.net/CET-NAP.htm
The sharp drop from 1650 to 1690 was followed by even steeper rise 1700-1740, neither can be explained by any charcoal or even the ‘witches burning’, but there are perfectly plausible natural reasons.
Is there not one inquiring journalist who would hold these ‘academics’ up for ridicule? Pointing out the discrepancies in what they have claimed and laugh at their claims? I realize that these people want tenure and more research funding – many of us have been there – but some of these claims would be cause to fail a first year undergraduate paper. I remember a similar claim that neolithic camp fires had caused the rise in temperature at the beginning of the Holocene. This type of paper does not merit serious discussion but should be seen as a source of humor; perhaps there ought to be some new competition for the most fatuous claims in a research paper?
At 0 AD the world human population was about 200 million.
It seems the Romans and Hans SUVs were some mo**erf***er big polluters!
Yes. Eyal Porat. You beat me to it. At 3% of curremt world polulation their per capita emissions would have to be 30 times higher. Without phone chargers to leave inadvertently!
Both abstracts have the flavor of stealth-and-run. “Here is the quandary….there MUST be an anthropogenic component”, seemingly disguised as an innocent summary of possible explanations for odd isotopic ratios. Result: that queasy feeling that someone is trying to smuggle the meme into the debate. But Wait! They don’t even smuggle in the second abstract…they just drive an armoured Semi full of weasel words straight through the checkpoint guardhouse!
An inquiring journalist? What an *intriguing* concept! Someone should try that.
I looked for the signature of the Black Death (around 1350), when a third of the world’s population, and half of Europe’s population died, and its well documented that large areas of farmland reverted to forest. Yet their pyrogenic CH4 ( from increased charcoal production) rises after 1350. Highly unlikely IMO. With the reduced population, metals and metal tools/weapons would have been in surplus, and smelting and smithing greatly reduced.
At least “climate scientists” cannot blame the British Empire for anything since it was spreading while we were emerging from the Little Ice Age!
Of course, if climate scientists could get rid of the Little Ice Age …
The madness deepens…
I think the Monty Python sketch about what the Romans have done for us is in need of a revision…
I blame it on that scene at the start of Gladiator – lots of carbon being produced by burning forests… a very none eco way to go about having battles..
We’re often told that we must reduce the global population and return to an agragrian paradise. But blimey, look what happened when the population was just 3% of what it is today and everyone was a farmer!
Population expansion occurred during warmer periods and population contraction occurred during cooler periods. Civilisations grew and developed more rapidly during the warmer periods and declined in the cooler.
Hardly surprising then that there was more human activity as civilisation leaped forwards in the warmer, more benign periods and less activity in the cooler periods when life was harsh and difficult.
This is no different to Gore’s false claims that CO2 rises preceded rather than followed temperature rise.
I wonder what the payment – sorry ‘grant’ – was for producing this nonsense.
Next: how to get rid of the Holocene Climatic Optimum (9,000 – 5,000 BP).
Onward and upward, comrades …
to quote Python from Life of Brian:
”and what have the Romans ever done for us?’…………
Infamy, infamy, they’ve all got it infamy…
http://m.youtube.com/watch?v=kvs4bOMv5Xw
Well some climate scientists belong in their very own ‘Carry On’ film!
Well at least we poor old Brits can stop worrying about being blamed for it all now, it’s the Romans, “what have they ever done for us?”, given us global warming it seems, on top of all the other ubiquitous stuff we often take for granted today, the aqueduct, the viaduct, roads, civil engineering, military engineering, law & order, irrigation, sanitation, education, hosptials, public health, public baths, art, Latin, central heating!
There are some tarts who give whores a bad name. Anything for the filthy lucre.
Ian W
More bull@ur momisugly#$%&*!! from the CAGW reactionaries. And the media’s blind acceptance of it is so heinous as to defy belief.
I’ve come to the conclusion that the mass media should be compelled by law, as a condition of their broadcast and publishing licenses, to report the truth along with their lies. There’s no problem of free speech, since they can go right along with their lying, but there is no reason why they should not be forced to also tell the other side of the story on AGW and any other such contentious issue. And they should be explicitly required to say that what they publish is their opinions, not necessarily facts, and that there are or may be views different from theirs.
If this sounds extreme – news reporting is a consumer product, and we require truth in packaging, truth in lending, and warning labels on hazardous products like cigarettes – why shouldn’t the news media be subject to the same standards as other businesses? They are capable of doing at least as much harm as the tobacco companies or crooked lenders. And it’s only a matter of honesty.
Of course the evil media empire will cry foul, but the real reason for that is that their tyrannical agenda and the lies they are telling would be promptly exposed for what they are, for all to see.
And I would apply the same strictures to the academic journals’ publishing licenses, and with respect to instruction in the universities – I would make accreditation conditional on their allowing and supporting all kinds of views on such issues as climate change.
Of course the academics will also squawk about this, but then they can be presumed to be like my former history professor colleague, who thought that the Soviet system was so much more efficient and humane than ours, 80 million murdered to the contrary notwithstanding – and said that was “a necessary step in reforming society.”
Given the CAGW crowd’s willingness to cause tens of millions of avoidable deaths through economic destruction, one would have to assume that those deaths are A-OK with them and a “necessary step in reforming society.” The next Holocaust, here we come! THAT’S the catastrophe we need to be on our guard for.
Heh, it’s easy. One don’t even need to deny the Medieval Climate Optimum any more, if only the Chinese industrial revolution of the Song Dynasty (宋朝; 960–1279 CE) could be blamed for it.
The per capita iron output rose sixfold between 806 and 1078, and by 1078 Song China was producing 127,000 t in weight of iron per year
They’ve even invented coke to prevent catastrophic deforestation, which was well under way by the end of this period due to charcoal overuse.
Now add climate change to the list…
If the abstracts diverge,with a period of almost six months between,then you really will need to check the full paper.
I had to read this twice and check it wasn’t April 1st, but yes, they really do seem to be claiming that. I guess a lot of the problem must have been all those 4 horsepower chariots in the Roman Games (vide ‘Ben Hur’) – horses fart just like cattle do, after all. Unbelievable, literally.
Plus, if they’re going to be consistent about this, then their next target must be to explain away the Minoan warm period, which was even warmer than the Roman. The entertainment value should increase yet further.
There is no consideration of solar radiation changes that will produce 13C from 12C and these data will not be available without much more research.
The whole paper relies on the iffy GHG theory. Other theories are available.
Is Celia Sapart any relation to Deirdre Spart of Private Eye fame ?
I remember many years ago being taught not to jump to conclusions about correlations between various variables. An example given to us, which I have always remembered, was that someone had observed that over a particular period an increase in the birth rate in Germany had occurred at the same time as an increase in the Stork population. And I am still convinced to this day that Storks do bring babies into this world because I saw the “facts” for myself! It appears Dr Sapart didn’t have the opportunity for a rigorous education I was fortunate enough to have.