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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Joel Shore (19:05:22)
That i the most disingenous sophistry i’ve ever read anywhere. To conflate things like that. Its the sort of logic which says that dog biscuits and lettuce are erily similar because they both have the in common a propensity to be eaten.
If that is the logic of an Anthropogenic Global Warming believer….
I actually find it quite entertaining, to your merit
Joel Shore likes smearing people with the “you are all creationists” epithet:
The big difference, Joel, is that the evidence for Evolution does not consist of a bunch of hastily cobbled-together computer simulations that have to be fudged to get the answers they want.
Fail.
This certainly doesn’t match the CO2 graph from Gore’s award-winning movie. What gives?
Joel Shore (14:02:33) :
Are you seriously telling me that you haven’t heard of Science? It and Nature are probably the two most prestigious interdisciplinary science journals in the world! Many scientists would probably sacrifice their first-born child to get a paper in there.
Thank you,Joel, I only knew the published paper and did not recognize the site as being the same . There is an ancient greek proverb: ” it does not come alone” , talking about all age and mental deterioration :).
Nevertheless, I would still like a link to the peer review policy, if anybody has managed to find it. This paper the way it is presented in PR seems to be bizzare.
proof:
“There is an ancient greek proverb: ” it does not come alone” , talking about all age and mental deterioration :).”
that should be “old age and mental deterioration”. :).
It’s getting that the Hockey stick shape is becoming a religious symbol to the Warminists….
They send young women to incense filled rooms armed with their hockey sticks and bones to shake rattles, while chanting arcane magiks, conjuring forth mystical graphs and statistics…. 😉
…. A rather creative field is this climate science. More an artform than science actually.
If CO2 was steady for thousands of years, then why did temps fluctuate so much (Roman Optimum, MWP and LIA)?
Proves to me that CO2 is not a driver.
Wow, the amount of hostility to science is staggering in this blog. Apparently, [snip]
Reply: Change your tone or post elsewhere. ~ charles the moderator
waooooo….!! so my question is what make the level CO2 decreased 800,000 years ago? . So if this research are 100% true, that fully support the truth of the bible about the creation….hehehehe
Well, if the CO2 levels were the same as today, but the temperatures were 5 to 10F warmer, then that would be evidence that CO2 is not a climate driver.
Wouldn’t it?
Joel Shore holds up James Hansen as the very model of a modern global warming moderate.
Is that the same James “death trains” Hansen then, that very modern global warming moderate?
Let me see, AGW skeptics are to Real Climate scientists as Creationists are to Evolutionists . . because neither Real Climate scientists or Evolutionists can prove that their theories are true . . . Joel shore.
Is there not a fallacy of reasoning here? If theory A cannot be proved and theory B cannot be proved then they must be either both true or both false. Therefore it is impossible to criticise theory A without also attacking theory B.
I think Joel should ask for a refund from his philosophy class.
The important aspect about using the paleoclimate data is that there is no “lagged warming” explanation available for the Hansen’s of the world.
The lags in the climate system can only be as long as 1,500 to 3,000 years as a maximum.
The paleo data extends beyond those lags so when you see CO2 staying at 250 ppm for 10 million years, then one can be sure that other things are impacting the climate beyond CO2/GHGs and these other factors must, in fact, be far more important.
If CO2/GHGs were as dominant as the theory says, then the last 20 million years should have been one big long ice age. Maybe not as big as the last glacial maximum but the glaciers should have extended into the mainland of North America for the entire period. Well, they didn’t and, in fact, it was much warmer than today in the period.
I’m assuming the cognitive dissonance of actually looking at the data and seeing that it does not match up with the theory, means they just don’t look at it anymore (or believe it). Which means they are constantly trying to find ways to adjust it. This is another one of those.
Richard Sharpe says:
First of all, that isn’t what the evidence for AGW consists of either. Second of all, you can find very similar complaints made about evolution.
Look, my point is simply this: The case of evolution shows us that people can always make arguments claiming that there is not empirical evidence to support a scientific theory if these people have a strong enough desire not to believe the theory. It is simply impossible to provide compelling evidence to someone who has set their standard of evidence to a level that cannot realistically be met. If they set themselves or people like them as the judge and jury of the evidence then the scientists can argue from now to eternity and it ain’t going to change theses people’s minds.
And, in both cases, we see the same pattern: namely a dramatic divergence of views between the scientific community in the field and recognized scientific authorities (like NAS and AAAS) vs “skeptics” of the theory, with the scientific authorities finding the evidence quite compelling while those dead-set against it do not.
There are two ways to explain this divergence: Either there is massive conspiracy, fraud, or delusion in the scientific community OR there are some people, some of them scientists and engineers but only a few of them actively publishing in the field, who because of their own biases find it very difficult to accept the evidence. Which of these do you think sounds most reasonable?
savethesharks says:
What about when Roy Spencer ( http://www.tcsdaily.com/article.aspx?id=080805I ) is in the room?
anna v:
Yeah…I know the feeling. And, alas I started to feel that way when I hit 30!
Well, you can probably find some info on their website. I’ve never submitted there but one thing I know from people who have is that, unlike many journals, which will send out just about any manuscript that they receive to referees, Science and Nature editors will often reject a manuscript outright themselves and will only send it on to referees if they can see clear evidence that it is very important and of broad interest.
Phil, I get that absorbed IR will heat the temperature in the air. But to affect the weather (IE cold fronts, warm fronts, pressure gradients, etc), that warmed air would then have to change the temperature of the oceans such that the jet stream and water cycle is changed to a degree large enough to overcome the self-limiting parameters of climate zones. Warm air is a very inefficient way to warm an ocean. It can only warm the very top mm layer, which then evaporates it back into the air nearly at the same time. Please tell me how CO2-warmed air involves itself in this cycle. Please use peer-reviewed mathematical calculations showing that longwave radiation is a more powerful heat source than shortwave radiation on ocean temps and that equatorial wind and current oscillation is no longer largely responsible for SST variations.
Yet another hockey stick. Being a petroleum geologist I have done a lot of studying on the past (which shows little to no corellation between CO2 and Temp) but also on what the IPCC has for future projections of CO2 emissions and temperature until 2100. Look at her graph at the beginning to see “IPCC projection” as the handle of the hockey stick. IPCC has 40 different cases in their model and they break out CO2 emissions by oil, gas and coal. In every case they project emissions several multiples greater than the currently know reserves. In their most extreme case they would have to assume an infinite supply of hydrocarbons. This is equivalent to saying you can pour 5 gallons of milk out of a one gallon jug. That along with their incorrect CO2 100 year retention time is what drives their predicition of runaway heating. It is criminal, but I have seen very little discussion of this subject.
There was an excellent Masters thesis written on this subject, only the first paragraph is not in English:
http://www.tsl.uu.se/uhdsg/Publications/Sivertsson_Thesis.pdf
pwl (10:36:53) :
How come this doesn’t jive with other studies of CO2 that I’ve seen? (At the moment I don’t recall the links to them.)
___________________
Please forgive me for being a grammar-Nazi, but it’s “jibe”, not “jive”.
******************
Lotharloo (02:53:11) :
Wow, the amount of hostility to science is staggering in this blog. Apparently, [snip]
**********************
Judging from your statement, I would suggest you don’t understand science. It is adversarial. You need to brush up on how science works. In the final analysis, if a garbage man proved Micheal Mann wrong and he wrote his thesis on a piece of garbage – Micheal Mann is wrong. Period.
Joel Shore (14:02:33) :
Are you seriously telling me that you haven’t
heard of Science? …Many scientists would probably
sacrifice their first-born child to get a paper in there.
Not to mention their scientific integrity!
AMAZING!!!!! our dollars working to better our lives… makes me all warm inside
i sure know its really gonna be great when all the leaders stop talking and outting into action all their most cherished objectives
Joel Shore says: The case of evolution shows us that people can always make arguments claiming that there is not empirical evidence to support a scientific theory if these people have a strong enough desire not to believe the theory.
Your comparison of the skeptic or climate realist arguments with that of creationism is a logical fallacy known as “poisoning the well”, a form of argumentum ad hominem. You knew that, right? But, that still doesn’t stop you from continuing to drag out the same old, tired tactics of Alarmists.
Then you say:… with the scientific authorities finding the evidence quite compelling while those dead-set against it do not. Here, you use two logical fallacies in one, that of the appeal to authority, and of Argumentum ad Populum or the “bandwagon fallacy”.
Finally, you say Either there is massive conspiracy, fraud, or delusion in the scientific community OR there are some people, some of them scientists and engineers but only a few of them actively publishing in the field, who because of their own biases find it very difficult to accept the evidence. This what is known as a false dichotomy, another logical fallacy. These and others are methods used by people who actually do not have a scientific leg to stand on.
Pamela Gray: You are getting yourself confused by trying to figure out how the heating occurs, which may be a subject of interest but is essentially irrelevant to the fact that the addition of greenhouse gases puts the earth – sun -space system out of radiative balance (i.e, the earth is receiving from the sun more energy than it emits back into space). The only way for this radiative balance to be restored is for the earth to emit more radiation back out into space and it does this by warming. Yes, the oceans have a large thermal inertia and explain why the process of restoring radiative balance takes a while.
However, no amount of worrying about how the solar and infrared radiation gets absorbed by the air, the oceans, etc. is going to get you around the First Law of Thermodynamics.
vrig: Your conclusions about how much fossil fuels are available are at odds with the peer-reviewed literature on this subject. See, for example, here http://www.sciencemag.org/cgi/content/abstract/sci;302/5652/1923 . The big player is coal, although there are also quite a bit of hydrocarbons when you count more exotic sources like the Canadian tar sands. That Science paper estimates the carbon in fossil fuel reserves as being 4000 gigatons of carbon (GtC) for conventional resources to 15,000 GtC for conventional plus exotic resources, which yields a range of concentration in the atmosphere from 1200 ppm to 4000 ppm. (I’m not sure exactly what their assumptions are concerning ocean and biosphere uptake of CO2.)
The venus missconception runs deep. Venus does have two things in common with Earth. That is it is a rocky inner planet with an atmosphere and it is similar in size to the Earth. That’s about it. Not only does Venus have a veritable ocean of CO2 underneath an atmosphere much closer to that of Earth – starting somewhere up around 50km above the surface, but it has several other factors that make it very alien.
First off, Venus receives relatively little solar energy because it has a solid layer of highly reflective clouds. Most of the incoming solar energy is reflected off due to the high albedo.
Second, Venus does not rotate the surface through day and night in a rapid fashion like the Earth or Mars. The same side of the planet is subject to much longer exposure to the energy – at least what gets through. Were one to dissipate the CO2 and reduce it to say 1000ppm in an atmosphere with surface pressure similar to that of Earth and cut out most of the highly reflective clouds, there would still be extreme heating of one side going on due to the lack of a significant rotation rate along with the extreme cooling of the night side.
Finally, the lack of large amounts of liquid water preclude having anything similar to an Earth system of climate.
“Phil. (20:14:14) :
Smokey (18:35:40) :
The CO2=AGW conjecture not been proven. The belief comes entirely from computer models, which starkly diverge from what the real world is doing.
It does not come from models it originates from the fact that CO2 is a strong absorber of the IR emitted from the Earth’s surface, as concentration increases the absorption increases.
”
CO2 is a mediocre absorber/emitter of IR. In a clear sky condition, CO2 is good for around 20% – assuming a typical overall average h2o vapor concentration. I’m not away of any legitimate estimates of clear skies representing even half of the Earth. Estimates range from 50% to 70% cloud cover. On average, when one includes cloud cover, one finds that the CO2 contribution dwindles to somewhere in the vacinity of 9-11% of the absorbed power.
As for CO2 absorption increasing with an increasing amount of CO2 in the atmospheric column, assuming a clear sky, that is true. However, this increase is a log scale factor. Hence the reason for the notion of doubling CO2. Each doubling of CO2 results in roughly a linear increment in absorption. Consequently, if you assume clear skies and an absence of conduction and convection, then at a given altitude you can expect that something like an additional 3 W/m^2 could be absorbed without re-emitting by doubling the concentrations from current to 2x current and a similar increase in W/m^2 for an increase from 2x current to 4x current (which brings us up to around 1200ppm). You would also find that there would be a similar decrease in W/m^2 for each halving in concentration from current levels for around 6 halvings and then a slightly lower W/m^2 effect for at least another 5 or 6 halvings below that.