Posted on 08/10/2010 1:05:07 PM PDT by Ernest_at_the_Beach
This image provided for timeline reference and is not from the study cited below
From the University of Leicester: An ancient Earth like ours
Geologists reconstruct the Earth’s climate belts between 460 and 445 million years ago
An international team of scientists including Mark Williams and Jan Zalasiewicz of the Geology Department of the University of Leicester, and led by Dr. Thijs Vandenbroucke, formerly of Leicester and now at the University of Lille 1 (France), has reconstructed the Earth’s climate belts of the late Ordovician Period, between 460 and 445 million years ago.
The findings have been published online in the Proceedings of the National Academy of Sciences of the USA – and show that these ancient climate belts were surprisingly like those of the present.
The researchers state: “The world of the ancient past had been thought by scientists to differ from ours in many respects, including having carbon dioxide levels much higher – over twenty times as high – than those of the present. However, it is very hard to deduce carbon dioxide levels with any accuracy from such ancient rocks, and it was known that there was a paradox, for the late Ordovician was known to include a brief, intense glaciation – something difficult to envisage in a world with high levels of greenhouse gases. “
A specimen of the chitinozoan species Armoricochitina nigerica (length = c. 0.3mm). Chitinozoans are microfossils of marine zooplankton in the Ordovician. Their distribution allows to track climate belts in deep time, much in a way that zooplankton has been used for climate modeling in the Cenozoic. A. nigerica is an important component of the Polar Fauna during the late Ordovician Hirnantian glaciation.
The team of scientists looked at the global distribution of common, but mysterious fossils called chitinozoans – probably the egg-cases of extinct planktonic animals – before and during this Ordovician glaciation. They found a pattern that revealed the position of ancient climate belts, including such features as the polar front, which separates cold polar waters from more temperate ones at lower latitudes. The position of these climate belts changed as the Earth entered the Ordovician glaciation – but in a pattern very similar to that which happened in oceans much more recently, as they adjusted to the glacial and interglacial phases of our current (and ongoing) Ice Age.
This ‘modern-looking’ pattern suggests that those ancient carbon dioxide levels could not have been as high as previously thought, but were more modest, at about five times current levels (they would have had to be somewhat higher than today’s, because the sun in those far-off times shone less brightly).
“These ancient, but modern-looking oceans emphasise the stability of Earth’s atmosphere and climate through deep time – and show the current man-made rise in greenhouse gas levels to be an even more striking phenomenon than was thought,” the researchers conclude.
Reference: Vandenbroucke, T.R.A., Armstrong, H.A., Williams, M., Paris, F., Zalasiewicz, J.A., Sabbe, K., Nolvak, J., Challands, T.J., Verniers, J. & Servais, T. 2010. Polar front shift and atmospheric CO2 during the glacial maximum of the Early Paleozoic Icehouse. PNAS doi/10.1073/pnas.1003220107.
Contacts: (Mark Williams and Jan Zalasiewicz at the Department of Geology, University of Leicester: Respectively tel. 0116 252 3642 and 0116 2523928, and e-mails mri@le.ac.uk and jaz1@le.ac.uk).
Possibly related posts: (automatically generated)
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Pamela Gray says:
Yet another paper attempting to report on important research but is shackled by its funding source: Likely provided by “green grants”, which specify what the grants can be used for. If you wish another grant, your published research must show that the grant was used for its stated purpose: investigations into global warming. It is most likely the only large sums of money available so you play the game to continue working in your chosen field.
Which leads me to this issue: Pacs and politicians on the stump are supposed to declare where they get their money, and money sources can’t be in the form of “laundered fronts”. Why? Because we have the right to know what compromises might be possible between these bed partners. Science has now also shown its willingness to compromise based on who is funding it. Therefore it may be time for laws to be passed about declaration of funding sources for any published paper providing research results, peer reviewed or not. Notice that currently, we must pay in order to read most research articles, including the bottom of the article that usually includes gratuitous mention of funding sources. The tax paying citizen is being forced to accept and even pay for a horse without being given the chance to look at its teeth before forking over money. A simple solution? Require published abstracts to also include funding sources.
fyi
Notice the closing:
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“These ancient, but modern-looking oceans emphasise the stability of Earth’s atmosphere and climate through deep time – and show the current man-made rise in greenhouse gas levels to be an even more striking phenomenon than was thought,” the researchers conclude.
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It would seem to had to include that in order to receive their funding.
An atmospheric pCO2 threshold for glaciation in the Late ...
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Geology; May 1997; v. 25; no. 5; p. 447-450; DOI: 10.1130/0091-7613(1997)025<0447:AAPCTF>2.3.CO;2
© 1997 Geological Society of America
1 Department of Geosciences and Earth System Science Center, Pennsylvania State University, University Park, Pennsylvania 16802
The Late Ordovician glaciation differs from other major Phanerozoic glaciations because of its short duration (
1 m.y.). A satisfactory explanation for this glaciation must be able to account for its sudden initiation, short duration, and rapid termination; mechanisms operating on tectonic time scales appear to be precluded. Given recent studies of a major perturbation in the carbon cycle during the glaciation, a climate model investigation of the sensitivity of the Late Ordovician climate to changes in atmospheric pCO2 was undertaken. Under the condition of a 4.5% reduction in solar luminosity, permanent snow cover (taken as a key indicator of potential for glaciation) is dramatically different between five experiments. The range of 18X present atmospheric level CO2 (ice free) to 8X ("runaway" icehouse) lies within the uncertainty of previous geochemical estimates of Late Ordovician atmospheric pCO2. The strong sensitivity to the modest direct forcing from pCO2 changes is due to the ice-albedo feedback. A plausible increase in organic carbon burial could have drawn down enough atmospheric CO2 to have briefly lowered the climate system below a critical glacial inception threshold at the end of the Ordovician. Conversely, a high pCO2 is required for the rest of the early Paleozoic, which was essentially ice free.
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Ordovician Period
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| Mean atmospheric O2 content over period duration | ca. 13.5 Vol %[1] (68 % of modern level) |
| Mean atmospheric CO2 content over period duration | ca. 4200 ppm[2] (15 times pre-industrial level) |
| Mean surface temperature over period duration | ca. 16 °C[3] (2 °C above modern level) |
| Sea level (above present day) | 180m; rising to 220m in Caradoc and falling sharply to 140m in end-Ordovician glaciations[4] |
The Ordovician [/ɔɹdəˈvɪʃən/] is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago (ICS, 2004,[5]. It follows the Cambrian Period and is followed by the Silurian Period. The Ordovician, named after the Welsh tribe of the Ordovices, was defined by Charles Lapworth in 1879 to resolve a dispute between followers of Adam Sedgwick and Roderick Murchison, who were placing the same rock beds in northern Wales into the Cambrian and Silurian periods respectively. Lapworth, recognizing that the fossil fauna in the disputed strata were different from those of either the Cambrian or the Silurian periods, realized that they should be placed in a period of their own.
While recognition of the distinct Ordovician Period was slow in the United Kingdom, other areas of the world accepted it quickly. It received international sanction in 1906, when it was adopted as an official period of the Paleozoic Era by the International Geological Congress.
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This ‘modern-looking’ pattern suggests that those ancient carbon dioxide levels could not have been as high as previously thought, but were more modest, at about five times current levels (they would have had to be somewhat higher than today’s, because the sun in those far-off times shone less brightly).
"Mssrs Williams, Zlackiewicz, and Vanderbrouke, can we discuss something here?" - Johnny Suntrade
"Certainly."
"Mssrs Williams, Zlackiewicz, and Vanderbrouke, you say that there is an accepted paradox during the Ordivician, given high pCO2 yet rapid glaciation, do you not?"
"Yes."
"And Mssrs Williams, Zlackiewicz,and Vanderbrouke, you maintain that the climate, and its variation, was similar to recent era's, do you not?"
"We do."
"Then you maintain that given the Sun's reduced insolation (intensity) during the Ordovician that pCO2 of that era simply could not be as high as previously suggested (15x) because the climate was the same as today, do you not?"
"We do so say."
"Then Mssrs Williams, Zlackiewicz, and Vanderbrouke are you not explicitly declaring that pCO2 in Earth's atmosphere is the cause of Earth's climate conditions?"
"Hmmmm, I guess we are saying that, yes, of course."
"Well Mssrs Williams, Zlackiewicz, and Vanderbrouke, that appears to us circuitous and presumptous logic. For after all that is the question of today is it not? I mean given that that is a totally arbitrary assumption, how can the Proceedings for the National Academy of Sciences allow you (as peer reviewed) to make such a circuitous statement, that because the climate was the same, pCO2 coupled to the Sun's output had to be the precursor for that era's glaciation?"
"Ahem, well Son, we do have to make some assumptions, and you know this WAS reviewed by the PNAS editors."
"OK, just saying. At least you do now consider the proper chronological proportions, hundreds of millions of years, to gain some perspective on phenomena that is yet significantly beyond our modeling comprehension. But then of course, 'the science is in' according to BO." -
Johnny Suntrade
UN panel: New taxes needed for a climate fund
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The world of the ancient past had been thought by scientists to differ from ours in many respects, including having carbon dioxide levels much higher – over twenty times as high – than those of the present.
Look on the bright side. OLD H.T. can only suck the oxygen out of a room these days...
:’)
Interesting work. And notice what university it came out of.
Meaning it’s not East Anglica???
Also note the publication. This is one of those closed publications that only accepts papers from warmers.
That’s the same crap publication that recently published an article claiming warmers are really smart and well educated and “climate deniers” are stupid and relatively uneducated, and restated the “scientific consensus” myth in favor of crap n trade.
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