![Cretaceous%20Map[1]](http://wattsupwiththat.files.wordpress.com/2013/09/cretaceous20map1.jpg?quality=83)
From the University of Missouri-Columbia
COLUMBIA, Mo. – For years, scientists have thought that a continental ice sheet formed during the Late Cretaceous Period more than 90 million years ago when the climate was much warmer than it is today. Now, a University of Missouri researcher has found evidence suggesting that no ice sheet formed at this time. This finding could help environmentalists and scientists predict what the earth’s climate will be as carbon dioxide levels continue to rise.
“Currently, carbon dioxide levels are just above 400 parts per million (ppm), up approximately 120 ppm in the last 150 years and rising about 2 ppm each year,” said Ken MacLeod, a professor of geological sciences at MU. “In our study, we found that during the Late Cretaceous Period, when carbon dioxide levels were around 1,000 ppm, there were no continental ice sheets on earth. So, if carbon dioxide levels continue to rise, the earth will be ice-free once the climate comes into balance with the higher levels.”
In his study, MacLeod analyzed the fossilized shells of 90 million-year-old planktic and benthic foraminifera, single-celled organisms about the size of a grain of salt. Measuring the ratios of different isotopes of oxygen and carbon in the fossils gives scientists information about past temperatures and other environmental conditions. The fossils, which were found in Tanzania, showed no evidence of cooling or changes in local water chemistry that would have been expected if a glacial event had occurred during that time period.
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  IMAGE: In the study, MacLeod examined fossils of organisms that lived 90 million years ago. This photo is an image from a Scanning electron microscope of a planktic (left) and benthic…Click here for more information. |
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“We know that the carbon dioxide (CO2) levels are rising currently and are at the highest they have been in millions of years. We have records of how conditions have changed as CO2 levels have risen from 280 to 400 ppm, but I believe it also is important to know what could happen when those levels reach 600 to 1000 ppm,” MacLeod said. “At the rate that carbon dioxide levels are rising, we will reach 600 ppm around the end of this century. At that level of CO2, will ice sheets on Greenland and Antarctica be stable? If not, how will their melting affect the planet?”
Previously, many scientists have thought that doubling CO2 levels would cause earth’s temperature to increase as much as 3 degrees Celsius, or approximately 6 degrees Fahrenheit. However, the temperatures MacLeod believes existed in Tanzania 90 million years ago are more consistent with predictions that a doubling of CO2 levels would cause the earth’s temperature could rise an average of 6 degrees Celsius, or approximately 11 degrees Fahrenheit.
“While studying the past can help us predict the future, other challenges with modern warming still exist,” MacLeod said. “The Late Cretaceous climate was very warm, but the earth adjusted as changes occurred over millions of years. We’re seeing the same size changes, but they are happening over a couple of hundred years, maybe 10,000 times faster. How that affects the equation is a big and difficult question.”
MacLeod’s study was published in the October issue of the journal Geology.
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CO2 levels of 1000 ppm will melt all the ice? Even if you believe in the “greenhouse gas” effect of CO2, the logrithmic nature of it will mean it has no effect from about 300 ppm onwards.
Obviously that sort of detail seems to be too technical for the authors.
One heck of an assumption – that CO2 levels are the cause of an ice-free earth! Where is the evidence to support such a quantum leap – what is the cause and effect – does CO2 drive temperature or temperature drive CO2 – or is some other mechanism at play
Andi
This is because CO2 is the only thing that controls climate. Therefore whatever conditions were like 90 million years ago is solely the result of the CO2 levels that existed at that time. So if CO2 returns to the levels that existed 90 million years ago, the climate will be exactly as it was 90 million years ago.
The continents will presumably realign themselves to where they were 90 million years ago as well.
This will happen 10,000 times faster than it did in geological times gone by because of human emissions, and that’s obviously why he’s worried. You can imagine the mayhem with the continents all moving about so quickly.
Powerful stuff this CO2. Makes perfect sense when you think about it.
(For those in any doubt, I am being sarcastic)
If there was no ice in Antarctica, well, that means that once the ice is gone we will likely be able to extract lots of oil from there!
Now seriously, no matter how fast we put CO2 into the atmosphere, even if the long-term status with that ammount of CO2 was an ice-free planet (which nobody has proved), it would take many thousand years to melt all that ice. Before that has any chance to happen, Milankovich cycles will bring back the ice.
Rubbish.Start with a CAGW meme and fit the paper around an already agreed conclusion. A simple Google for ice sheets in Late Cretaceous destroys this paper.e.g.
“Milankovitch forced cyclic alternations from drier to wetter climatic periods caused vegetation variability from 72 to 77Ma. This climate change was probably related
to the waxing and waning of ephemeral (100 ky) small ice sheets in Antarctica during times of insolation minima and maxima. Drying and cooling after 72 Ma culminated from 68 to 66 Ma, mirroring trends in global δ 18 O data” – Gallagher et al, Science Direct, 2008.
Unlike the MWP in Greenland, which was a local thing, if Tanzania didn’t have glaciers, I guess the whole world didn’t. But then again, that was before Tanganyika and Zanzibar merged, which I doubt was taken into account in the study.
CO2 driving temperature again.
It’s not all bad. Intercontinental flights will be cheaper.
We are probably dealing with the biggest scientific fraud in History since this paper: 1981_Hansen_etal.pdf (published in ‘Science’)
Para 2; the claim that CO2 blocks IR in the range 7-14 microns (two small bands at ~ 10 microns) is wrong. The correct 15 micron band would only cause 1.2 K surface temperature increase for no change of OLR spectral distribution as [CO2] varies; untrue.
Para 4; the 33 K ghe claim fails to account for the loss of cloud and ice albedo if ghgs were taken from the atmosphere, giving 43% SW energy increase: real ghe ~ 11K; 3x positive feedback wrong from the start.
This passed peer review hence this IPCC mantra is shown up to be ‘Believe us because we conned you in the past.’. In reality CO2 climate sensitivity is probably <0.1 K.
[snip -inappropriate – mod]
Good heavens, I just followed a link to here from http://www.bbc.co.uk
Where are the “p” values, and what was the confidence interval? Certainly, there are some numbers associated with this “study”, or is it just another press release in the run-up to AR5?
During the late Ordovician temperatures were much lower and CO2 ppm over ten times higher than today.
“Late Cretaceous Period was likely ice-free….At the rate that carbon dioxide levels are rising, we will reach 600 ppm around the end of this century. At that level of CO2, will ice sheets on Greenland and Antarctica be stable?” Yada yada, CO2 waffle CO2.
What about the position of the continents, Numbskull? Antarctica is not isolated, no cirumpolar vortex etc, etc. How can you make direct comparison? You can’t. It’s hand-waving.
“This finding could help environmentalists and scientists predict what the earth’s climate will be as carbon dioxide levels continue to rise.”
Indeed, for a start it shows that there is not run-away climate change/tipping point/climate catastrophe with the “ocean boiling way” al a Hansen.
Climate is stable a 1000ppmv CO2 and at much higher temps. As stable as it is now.
Robin Hewitt said, 1:42am
“Good heavens, I just followed a link to here from http://www.bbc.co.uk“.
Now that does it for me, I can believe most things within the climate debate but this is ridiculous. A link from the BBC to WUWT, I suggest more water with whatever you’re drinking Rob. 😉
And we tax payers pay them to produce this “study”.
“So, if carbon dioxide levels continue to rise, the earth will be ice-free once the climate comes into balance with the higher levels.”
Spurious and false assumption that temperature stabilises to match CO2 when the climate record clearly shows it is the opposite.
When “the climate comes into balance” it will have reabsorbed the excess CO2 to the level determined by temperature.
That day is a long way off and we almost certainly will not be here to worry and tweet about it. Real problems will likely intervene in the future of society long before then.
I thought I’d read that the ice caps only formed after North and South America joined up and stopped the warm Pacific water flowing into the Atlantic. 1000 ppm of CO2 didn’t cause that.
Yes we had an ice age in the Ordovician period, with very high levels of CO2
AleaJactaEst says:
Rubbish.Start with a CAGW meme and fit the paper around an already agreed conclusion. A simple Google for ice sheets in Late Cretaceous destroys this paper.e.g.
In what way does the fact you get a match for certain keywords on Google “destroy” the paper.
Sceptical science requires thought not stupidity. Try again.
It’s a conspiracy to drive sand bag prices to an all-time high.
Hand to face in despair… so we are back to 6 degrees now? These people just will not give up. Just when we thought that some sanity was starting to take hold. I can hardly bear to read this kind of simplistic reasoning any longer. This CO2 meme rivals the survival capacity of a cockroach. It just will not DIE! (Great little creatures, no?)
Greg Goodman
The criticism is quite well placed. They can only draw their conclusions (linking CO2 to global ice) by assuming that CO2 is the only thing, whether directly or indirectly, that drives climate. They make an assumption to support a hypothesis. Is this really good science or just the same old trite dressed up as new research.
Actually there are strong indications that there were fair-sized icecaps inland in Antarctica at least intermittently during the Cretaceous. The main reason to believe this is that there were many (geologically) abrupt changes in sea level on the order of tens of meters which are difficult to explain except through the formation and melting of reasonably large icecaps. They were probably never large enough to reach the coast though.
Unfortunately the interior parts of Antarctica aren’t easily available for research, but there is very strong evidence for a cool temperate climate with winter temperatures well below freezing from Southern Australia.
That the water temperature in Tanzania wasn’t affected by inland icecaps in Antarctica isn’t exactly startling – it wasn’t much affected even by the recent worldwide glaciations. As for “water chemistry” I suppose he means oxygen isotope ratios, since the chemistry of tropical oceans would not be affected by glaciations in Antarctica in any case. It is also doubtful how well ice in Antarctica would show up in isotope ratios in the tropical Tethys, there wasn’t any cold Antarctic Deep Water in the oceans then, and if the ice-volume didn’t change markedly during the studied interval there would be no signal at all in tropical foraminifera. Unfortunately there is no information on how long the studied interval was, or its exact stratigraphic position so it’s impossible to correlate it with the sea-level curve.
Can it? I only ask because the continents’ positions look very different today as well as ocean circulations. And the Isthmus of Panama which formed 3 million years ago also changed the climate patterns which also helped form the Arctic? Then there is Antarctica. During the late Ordovician ice age co2 was over 10 times higher than today.
Can someone more knowledgeable than me explain how this study helps “environmentalists and scientists predict what the earth’s climate will be as carbon dioxide levels continue to rise”?