Another paper for the Copenhagen train. This is an estimate according to the abstract. Here’s the abstract and the supplemental information, of course the publicly funded paper is behind the AAAS paywall.
From UCLA News: Last time carbon dioxide levels were this high: 15 million years ago, scientists report
By Stuart Wolpert October 08, 2009 Category: Research
You would have to go back at least 15 million years to find carbon dioxide levels on Earth as high as they are today, a UCLA scientist and colleagues report Oct. 8 in the online edition of the journal Science.
“The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit higher than they are today, the sea level was approximately 75 to 120 feet higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland,” said the paper’s lead author, Aradhna Tripati, a UCLA assistant professor in the department of Earth and space sciences and the department of atmospheric and oceanic sciences.
“Carbon dioxide is a potent greenhouse gas, and geological observations that we now have for the last 20 million years lend strong support to the idea that carbon dioxide is an important agent for driving climate change throughout Earth’s history,” she said.
By analyzing the chemistry of bubbles of ancient air trapped in Antarctic ice, scientists have been able to determine the composition of Earth’s atmosphere going back as far as 800,000 years, and they have developed a good understanding of how carbon dioxide levels have varied in the atmosphere since that time. But there has been little agreement before this study on how to reconstruct carbon dioxide levels prior to 800,000 years ago.
Tripati, before joining UCLA’s faculty, was part of a research team at England’s University of Cambridge that developed a new technique to assess carbon dioxide levels in the much more distant past — by studying the ratio of the chemical element boron to calcium in the shells of ancient single-celled marine algae. Tripati has now used this method to determine the amount of carbon dioxide in Earth’s atmosphere as far back as 20 million years ago.
Aradhna Tripati
“We are able, for the first time, to accurately reproduce the ice-core record for the last 800,000 years — the record of atmospheric C02 based on measurements of carbon dioxide in gas bubbles in ice,” Tripati said. “This suggests that the technique we are using is valid.
“We then applied this technique to study the history of carbon dioxide from 800,000 years ago to 20 million years ago,” she said. “We report evidence for a very close coupling between carbon dioxide levels and climate. When there is evidence for the growth of a large ice sheet on Antarctica or on Greenland or the growth of sea ice in the Arctic Ocean, we see evidence for a dramatic change in carbon dioxide levels over the last 20 million years.
“A slightly shocking finding,” Tripati said, “is that the only time in the last 20 million years that we find evidence for carbon dioxide levels similar to the modern level of 387 parts per million was 15 to 20 million years ago, when the planet was dramatically different.”
Levels of carbon dioxide have varied only between 180 and 300 parts per million over the last 800,000 years — until recent decades, said Tripati, who is also a member of UCLA’s Institute of Geophysics and Planetary Physics. It has been known that modern-day levels of carbon dioxide are unprecedented over the last 800,000 years, but the finding that modern levels have not been reached in the last 15 million years is new.
Prior to the Industrial Revolution of the late 19th and early 20th centuries, the carbon dioxide level was about 280 parts per million, Tripati said. That figure had changed very little over the previous 1,000 years. But since the Industrial Revolution, the carbon dioxide level has been rising and is likely to soar unless action is taken to reverse the trend, Tripati said.
“During the Middle Miocene (the time period approximately 14 to 20 million years ago), carbon dioxide levels were sustained at about 400 parts per million, which is about where we are today,” Tripati said. “Globally, temperatures were 5 to 10 degrees Fahrenheit warmer, a huge amount.”
Tripati’s new chemical technique has an average uncertainty rate of only 14 parts per million.
“We can now have confidence in making statements about how carbon dioxide has varied throughout history,” Tripati said.
In the last 20 million years, key features of the climate record include the sudden appearance of ice on Antarctica about 14 million years ago and a rise in sea level of approximately 75 to 120 feet.
“We have shown that this dramatic rise in sea level is associated with an increase in carbon dioxide levels of about 100 parts per million, a huge change,” Tripati said. “This record is the first evidence that carbon dioxide may be linked with environmental changes, such as changes in the terrestrial ecosystem, distribution of ice, sea level and monsoon intensity.”
Today, the Arctic Ocean is covered with frozen ice all year long, an ice cap that has been there for about 14 million years.
“Prior to that, there was no permanent sea ice cap in the Arctic,” Tripati said.
Some projections show carbon dioxide levels rising as high as 600 or even 900 parts per million in the next century if no action is taken to reduce carbon dioxide, Tripati said. Such levels may have been reached on Earth 50 million years ago or earlier, said Tripati, who is working to push her data back much farther than 20 million years and to study the last 20 million years in detail.
More than 50 million years ago, there were no ice sheets on Earth, and there were expanded deserts in the subtropics, Tripati noted. The planet was radically different.
Co-authors on the Science paper are Christopher Roberts, a Ph.D. student in the department of Earth sciences at the University of Cambridge, and Robert Eagle, a postdoctoral scholar in the division of geological and planetary sciences at the California Institute of Technology.
The research was funded by UCLA’s Division of Physical Sciences and the United Kingdom’s National Environmental Research Council.
Tripati’s research focuses on the development and application of chemical tools to study climate change throughout history. She studies the evolution of climate and seawater chemistry through time.
“I’m interested in understanding how the carbon cycle and climate have been coupled, and why they have been coupled, over a range of time-scales, from hundreds of years to tens of millions of years,” Tripati said.
In addition to being published on the Science Express website, the paper will be published in the print edition of Science at a later date.
UPDATE: Bill Illis add this graph in comments, which brings up the obvious correlation questions.
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“We are able, for the first time, to accurately reproduce the ice-core record for the last 800,000 years — the record of atmospheric C02 based on measurements of carbon dioxide in gas bubbles in ice,” Tripati said. “This suggests that the technique we are using is valid.
“We then applied this technique to study the history of carbon dioxide from 800,000 years ago to 20 million years ago,” she said. “We report evidence for a very close coupling between carbon dioxide levels and climate. When there is evidence for the growth of a large ice sheet on Antarctica or on Greenland or the growth of sea ice in the Arctic Ocean, we see evidence for a dramatic change in carbon dioxide levels over the last 20 million years.
Hum for the first time we accurately go back 800,000 Years? Then just how inaccurate is the 800,000 to 20 million measurements. I am sure Al would be interested, seeing his movie makes claims of knowing CO2 levels well past the first time accurate measurements have been done… ptfff
Please forward the data to Steve McIntyre for debunkage…
I am not abosolutely sure that Science is a peer reviewed publication, but if I recall correctly it is not. Therefore, using the AGW standard we can ignore this article and go one with our business.
The train is rushing to the Copenhagen Station, but most people got off when it became obvious that the engineer was insane. All those left on board are self deluded activists and other Nobel Prize winners.
Hope they don’t get too hurt when the train reaches the station and they become aware that nobody is waiting for them and the brakes were jettisoned a long way back.
Balony!
Has anyone stopped to think about this?
By far the majority of All GHG is put into the atmosphere NATURALLY.
Mankind only contributes a spit in the ocean of GHG.
So any increase in CO2 can be attributed to nature not man.
And since the entire amount of natural increase in CO2 is almost all naturally occuring, what exactly is the big wupp?
CO2 goes up and it goes down like ocean tides. The tiny amount we contribute to it could not possibly change the natural variation.
It is like spitting into the ocean and then claiming credit for the rising tide.
Give the poor girl a break. She is merely an Assistant Professor. How in the world do you think a young Assistant Profoessor gets a promotion to Full Professor at a prestigious college like UCLA these days?
Well I can assure – it is NOT by being honest. It is about publishing papers and making speeches that INCREASE FUNDING for University Research.
Duh! How do you think science works these days? Do you think all those conventions and boondogles come free…do you think that living in sunny California is easy on an Assistant Professor’s salary.
Have any of you read about how extremely hard it has been for Svensmark to get his work published and to get funding???
This kind of verbal diarrhea from Ms Tripati will no doubt be plastered ALL OVER the NEWS – gaining prestige for UCLA.
Well Done Ms Tripati – that is the spirit!
snip – Adolfo, a climate skeptic, has been banned for posting inflammatory commentary that violated blog policy on several occasions, then trying several different personages ( a total of five) to get around it. His comments are no longer welcome here due to this behavior.
– Anthony
I’m not a scientist, so I can’t question the study itself or its methods. I just can’t quite see how the study does anything but demolish the theory that CO2 is the driver of climate and warming. If 15 million years ago CO2 levels were what they are today, but temperatures were 5-10C warmer, doesn’t that mean that CO2 levels have little or nothing to do with global warming trends? Clearly, something other than CO2 was making the earth much warmer then. Thus, there’s no reason to think that our current CO2 levels are driving any warming trends, or we would expect to already see huge warming trends, not the miniscule 0.8C trrend of the last century.
Have these scientists actually considered all the other factors which might have led to the world of 15 million years ago being 5-10C warmer than the present world? Surely CO2 can’t be the only difference. Isn’t science supposed to investigate all those other factors and only after eliminating them, conclude that CO2 levels were responsible for that warming?
Maybe I’m just not smart enough to be a scientist.
Terryskinner (10:43:37) :
“Fantastic news:
Two periods of Earth History with the same CO2 levels but temperature very different and sea level very different. Conclusion: The level of CO2 does not determine either temperature or sea level.”
Yeah, that was the first thing that struck me, too. Assuming everything in the paper is true (big assumption), CO2 apparently doesn’t have much effect on climate any more–it has “lost” 5 to 10 degrees of warming ability in 15 million years. We can continue to fertilize the atmosphere with no adverse consequences! I was just about to call President Obama with the good news.
Then I realized that this is actually terrible news. If the warming effect of this essential climate-warming gas continues to decay at the same rate, the earth is doomed, DOOMED I tell you, to an eventual permanent ice age, no matter how much fossil fuel we burn!
Our only hope is that “greenhouse decay” makes Venus habitable before we all freeze here!
The Other Hockeystick?
I have some difficulty in accepting that the data from the ESRL global CO2 measurement programme ( Mauna Loa, etc.) reflects changes in the actual quantity of CO2 in the Earth’s atmosphere.
I have looked at the methodology and as I understand it, the ERSL measurement is a relative one, i.e. of the ratio of CO2 in an airflow, which is shown to be increasing steadily. This is taken by others to mean that the absolute quantity of atmospheric CO2 is increasing, and the metaphysicians predict dire consequences for those naughty humans.
I should like to propose an alternative interpretation; that the data reflects an absolute decrease in atmospheric O2.
The burning of carbon in the atmosphere produces CO2 which Henry’s law predicts will be almost completely absorbed by the oceans, as it is very soluble. However, only a tiny proportion of the lost atmospheric O2 will be replaced via ocean outgassing, as it is much less soluble than CO2. So, when carbon is converted to CO2, the net effect is a loss of atmospheric O2 almost on a molecular one-for-one basis.
It follows that by measuring and reporting increased atmospheric CO2 in units of parts-per-million, the absolute amount of CO2 in the atmosphere may not be rising, but rather it is the proportion that is rising.
I appreciate that my view may be entirely and completely erroneous and stemming from ignorance, so I would very much appreciate critical resonses, in order to correct my thinking.
If however my alternative view has some scientific merit, the consequences at least for the metaphysicians could be awesome.
“During the Middle Miocene (the time period approximately 14 to 20 million years ago), carbon dioxide levels were sustained at about 400 parts per million, which is about where we are today,” Tripati said. “Globally, temperatures were 5 to 10 degrees Fahrenheit warmer, a huge amount.”
A clean thinker reads this as current temps aren’t anywhere close to what they were in the past at similar CO2 levels, therefore, temp & CO2 evidently arent that well correlated & there must be other more significant forcing mechanisms in play that need to be considered.
Of course, the author throws in the word “sustained” to imply that’s where we are heading. Proof please ? Is that too much to ask?
Without the entire article, it’s kind of pointless to argue about it. Does anyone know of any studies on the rate of CO2 diffusion through solid ice?
Give the woman a Nobel Prize, for creativity. Or, should that be a Nobrain prize?
Gives me yet one reason to drop my AAAS membership. If it was important, they should have peer-reviewed it and included it in their print edition. They didn’t.
R Taylor (10:59:21) :
You stated:
“Why does no-one pay attention to the lag of CO2 behind temperature? The only reasonable explanation is that temperature controls CO2. There is no empirical evidence that “carbon dioxide is a potent greenhouse gas.” We exceeded the highest CO2 in the last million years by 1910. On a 100-year time scale, the greenhouse effect in the atmosphere should be instantaneous. It isn’t there.”
1) Up until the last 100 years there has not been another species pumping gigatons of CO2 into the atmo on a yearly basis. Perhaps that’s what makes our situation unique. There is nothing “natural” about pumping out CO2 and paving over 25% of the landmass of the planet. I would not expect “climate” to react in a “normal” way.
2) Normally CO2 would lag temperature increases perhaps triggered by changes due to something like the Milankovitch cycle. But CO2 levels would inch up gradually over hundreds of years. But what man is doing to the atmo by loading up CO2 is not normal so the empiral evidence will be what we experience over the next 50-100 years.
3) The effect of changes in CO2 on temp should be instantaneous? That’s wishful thinking but not reality based. We may be only experiencing the beginning of the effects of higher levels of CO2. Our grandchildren will feel the brunt of any negative effects to the planet.
It’s similar to the USA economy. Accumulate trillions in debt and wish that it won’t have an impact on the next generation who is saddled with it. Are we willing to mortgage our children with the potential consequences of +3-5C over the next 100 years?
Shiny
William
When will see this is another case of proxy abuse?
Will it be shown in time to make a difference?
Since we know that the other proxy-derived hockey sticks are bogus, the fact that this latest one is also a hockey stick strongly leads to the conclusion of its bogosity, as well.
Clearly the fact that C02 was rock steady proves that mankind’s evil activity has caused recent levels to skyrocket. We are evil, the science is settled. Of course since C02 drives temperature as everyone knows, (except for the evil denialists) that historical temperatures must also have also been rock steady. Any references to the MWP and LIA are obviously lies fabricated by the evil capitalist (oops, sorry about the spittle) dogs who will stop at nothing to destroy our planet.
Remember the simple facts that prove AGW is indisputable.
1. Hot –> it is AGW. (Everywhere there are no witnesses, except Texas!!!)
2. Cold –> it is AGW. (Everywhere else except Texas, Go Texas!!!)
3. Drought it is AGW. (Texas again!!!)
4. Flood –> it is AGW. (Jim Cantouri and Texas says so)
5. Less ice –> it is AGW. (Arctic) Look Texas doesn’t even have ice –> AGW
6. More ice –> it is AGW (Antarctic) (Flaw in data must adjust.)
These simple rules never fail. Proof positive, all skeptics will burn!!!
Here is CO2 versus Temperature over the last 30 million years.
http://i37.tinypic.com/1z3qmg4.jpg
REPLY: Bill please source the data for this graph. – Anthony
It used to be
end of ice age
temps up
co2 up
temps more up because of
temps down
co2 lagging behind for slow slide into next ice age
now it will be, for physics does not change
end of ice age
temps up
co2 up
temps more up because of
anthropogenic introduction of far more CO2 <<<<<<
temps even more up… to that of 15 million year ago level
clathrates kicking in
fried
how about that scenario?
biosphere collapse, societal collapse, war, hunger, thirst, nuke em
In the last 20 million years, key features of the climate record include the sudden appearance of ice on Antarctica about 14 million years ago and a rise in sea level of approximately 75 to 120 feet.
The Younger Dryas no doubt. But this digs up more questions than it answers.
A lot less ice in the NH and after the Younger Dryas even less ice worldwide.
So with falling Ice worldwide (a warming planet) you get falling C02?
A melted Laurentide is replaced by an Antartic Ice Cap. How then did the sea levels rise?
“A slightly shocking finding,”
“We have shown that this dramatic rise in sea level is associated with an increase in carbon dioxide levels of about 100 parts per million, a huge change,” Tripati said.
How? Melt one area and freeze it elsewhere. Where did the C02 come from?
If the Laurentide melts the forests grow up and the C02 is locked in the forest. The tundra remains frozen. The C02 leaching out of coal, oil & gas support the new growth.
So, how did we get a warmer planet and less C02 after the Laurentide melt?
This report is circular reasoning at it’s pinnacle.
“conradg (11:19:11) :
I’m not a scientist, so I can’t question the study itself or its methods.”
That may be true, but you know at this point in time some of the qualified scientists seem out of touch with reality. (This doesn’t mean that all who have qualifications are like this.)
However, there are countless failed predictions by “experts” (*cough cough* Arctic sea ice minimum 2009), whilst many “non-scientists” who study climate as a hobby and who contribute here share interesting ideas and theories which are more worthwhile than the worn out hockey sticks and computer models which the “experts” constantly regurgitate on the table.
John G. references a map presented at the Freeper site. Looking at that map, I am struck by the upper bound of average global (I know, E.D.) temperatures that with 2 exceptions doesn’t seem able to break about a 22 degree C. boundary over the past 600 million(!) years, and that today is aout half of that bound. I don’t know how this graph was derived but, if valid, would indicate that there is some very powerful feedback mechanism that doesn’t allow temps to go hog wild beyond a certain point. The fact that CO2 steadily falls would indicate that there is little correlation between the two.
This is all likely common knowledge to regulars here but it is pretty striking to this lurker.
Gary Hladik (11:21:30)
You stated: “Our only hope is that “greenhouse decay” makes Venus habitable before we all freeze here!”
Unlike Earth, Venus does not generate a magnetic field. This is significant because Earth’s magnetic field protects its atmosphere from the solar wind. On Venus, however, the solar wind strikes the upper atmosphere and carries off particles into space. This has stripped away most of the water in the atmosphere of Venus leaving only 20 ppm of water vapor in the atmo.
Venus’ carbon dioxide-rich (96.5%) atmosphere is almost 100 times more dense than the Earth’s and acts like a blanket. As a result, Venus’ surface temperature is hotter than that of even Mercury, which is twice as close to the sun. The remaining portion of the atmo is 3.5% Nitrogen. Not much O2 to breath.
Without a magnetosphere and plate tectonics Venus will remain a hot very dead world. We may be capable of emulating Venus if we can get CO2 up over 1000ppm. Should we give it a try?
Shiny
William
“During the Middle Miocene (the time period approximately 14 to 20 million years ago), carbon dioxide levels were sustained at about 400 parts per million, which is about where we are today,” Tripati said. “Globally, temperatures were 5 to 10 degrees Fahrenheit warmer, a huge amount.”
Headline:
Scientists prove No link between CO2 and temperature.
CO2, too subtle.
Take the temperatures from Vostok, add a few years from a volcano in Hawaii, project into the future…
Nobel!
The staging of this is simply disgusting and she participates so willingly to the show…
There is clearly a confusion of scale, causes and effects in this announcement whose goal is to silence the highly skeptical geoscientist community with spurious teleconnections.