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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This video was posted on WUWT a while back: click. It deconstructs the conjecture that CO2 can cause catastrophic global warming.
And the alarmist crowd always uses the Mauna Loa CO2 chart with a very high starting y-axis: click. Using a y-axis like this is deliberately alarmist.
But using a y-axis that starts at zero gives the true picture: click. Not so scary, is it?
And Dr Roy Spencer’s graph puts the trace gas CO2 in perspective: click. [The graph line is along the bottom of the chart.]
Conclusion: they’re lying to us about the effect of CO2, which is a beneficial trace gas that is every bit as essential as H2O to life on Earth.
Finally, to claim that 15 million years ago CO2 was higher begs the question: where were the SUVs then? In fact, CO2 has been much higher in the past: [click on the image to expand].
Picking 15 million years was entirely arbitrary. The chart linked above goes back hundreds of millions of years, and gives a much better picture of past atmospheric CO2 levels.
Jim (11:23:18) :
I wonder that myself. What C02 sources lie below the ice that can permeate upwards, giving the impression of rising C02 levels the deeper one drills?
If it’s vulcanism, then if one drills an area pattern, a dome of trapped C02 would appear in the results.
A key question to be answered.
Drill here, drill now.
“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.”
As a UCLA grad I am disappointed in the lack of logic in this phrase
I thought MELTING of ice on land caused sea levels to rise. Did the ice, which suddenly appeared on Antarctica come from outer space? and where did the water for the sea level rise come from.
I don’t think that these kind of “scientific” leaps of faith reflect well on the female gender.
Signing off: a sad UCLA engineer (of the female persuasion)
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
So why we do not have those temperatures and sea levels today? Why Antarctic is one full sh*tload of ice? Oh we know, in 2100 it may happen that..
The lady itself is not that bad.
The global cooling news just keeps getting better.
California and Colorado ski resorts in a snow daze
http://travel.latimes.com/daily-deal-blog/index.php/california-resorts-i-5594/
Maybe I’m just not smart enough to be a scientist.
conradg,
You don’t have to be a scientist to use logic. That’s what I find so amazing about the AGW crowd, they have no problem with the illogical, or just making stuff up. Here was a good one, AGW activist proclaims that CO2 is the “most important greenhouse gas and without it, temperatures would be 60F cooler than they are.” (I guess that was just to assure us how important it was) When it was pointed out, that no, water vapor is the primary greenhouse gas on earth, the retort was that water vapor may be important but unlike CO2 it doesn’t stay in the atmosphere, because it comes out of the atmosphere as precipitation and that’s why it is CO2 that is causing warming. You’d like to laugh, but these people get to vote.
Lets assume this CO2 record is accurate. It doesn’t say how CO2 levels rose in the 20-15 million year ago period. Whatever the reason, it certainly is different than the recent increase.
There’s an assumption here that a CO2 increase means a temperature increase, but it sure would be nice to know why CO2 levels rose back then and consider what effects those processes would have on the climate instead of saying CO2 is the only driver.
Anthony, 11:37,
I will be making all the paleoclimate data (temperature, CO2, sea level) together with links to all the sources available soon in easy to use spreadsheet form.
The CO2 data for the chart comes from the Antarctic ice cores to 800K and then from Pangani 2005 to 30 million years ago. The temperature estimates come from Zachos 2001 (I could have put the ice core temperature numbers in as well but the chart gets too cluttered).
Here is another preview.
http://i37.tinypic.com/20toyro.jpg
william (11:43:39) : “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.”
Well duuhhhh. We’ll have to bring a lot of ice with us, won’t we? 🙂
Sorry, that should read Pagani 2005. I always spell that wrong.
Shoddy Journalism is correlated with recent increases in CO2. Image how bad the media was 15 million years ago….. 😉
It was warmer 15 million years ago and the sea levels were higher? Sounds to me like CO2 has little to do with it. If CO2 levels caused it, why isn’t the climate today like it was then?
There are serious debates about the accuracy of CO2 measurements from ice cores. Ice — even glacial ice hundreds and even thousands of feet deep — is not solid. It is permeable.
See this graph on Co2 and temperature during the Cretaceous and early Tertiary which does not show much correlation.
I don’t understand why there was no “runaway greenhouse effect” when C02 was much higher than today? Where is the “tipping point?”
http://www.geocraft.com/WVFossils/PageMill_Images/image277.gif
They made their analysis by using AA spectroscophy, and being both elements, boron and calcium, obviously in the percentage level, it is not the correct procedure, as it gives too much error.
Boron and calcium are usually found as:
Colemanite (Hydrated Calcium Borate)
2CaO, 3 B2O3, 5H2O : CaO, 27.2%; B2O3, 50.9%; H2O, 21.9%.
Ulexite (Hydrated Sodium Calcium Borate)
Na2O, 2CaO, 5 B2O3, 16 H2O : Na2O, 7.7%; CaO, 13.8%; B2O3, 43.0%; H2O, 35.5%.
in VOLCANIC areas.
They are also extrapolating backwards to million of years, a sùpposed relation of both elements to sea´s pH, which could have been affected by many other acids/alkalies.
This is baseless.
william (11:30:42) : There is nothing “natural” about pumping out CO2 and paving over 25% of the landmass of the planet.
Have you ever been outside of NYC?
Jim (11:23:18) :
Without the entire article, it’s kind of pointless to argue about it.
Agreed. Except press releases (this one is flawed) are all most people read.
“Tripati’s new chemical technique has an average uncertainty rate of only 14 parts per million.”
It’s so nice to be certain!
conradg (11:19:11) :
Correct. You are not smart enough to be a scientist because you clearly have a lot of common sense. And sadly common sense is not very common.
The global warmers are manifestly not serious — if they were, the solutions they propose to global warming would be ones that would be more likely to work. For example: a crash program of space construction to give us the capability to build big flat panels in space to shade the earth if in fact it does start to warm up. The same technology has the added benefit of being easily converted to giant solar mirrors, diverting more solar energy onto the earth if another ice age begins, halting it in its track. If you’re serious about having an effect on the earth’s climate, this is the way to be thinking — not trying to monkey around with trace gasses in the earth’s atmosphere. Note that there is ample evidence that ice ages regularly occur and we are (more or less) due for another one soon, geologically speaking.
I have access to the paper Anthony…shoot me an email if you want it and I will forward it to you
william:
1000 ppm? You’re not even remotely close to what it would take to emulate venus. Go for 100,000 ppm AND move the Earth closer to the sun, then maybe we’ll start to see some real effects. You should really consider learning more about physics.
25% of the landmass is paved now? I guess you never fly, do you? Flying (and actually looking out the window) is a humbling experience, as you realize just how miniscule our presence is on the planet.
And Hearndon, the entire article is wrong. All of it. I’d check that she spelled her name right if I cared. There is nothing to argue, since it has clearly left the Science building and taken a stroll over to the Fiction wing.
Just google “vostok”, and you’ll discover that the “straight line” of historical CO2 isn’t even remotely close.
OT: Rasmus at RC attacks Svenmark.
I posted a comment and just in case it is snipped… It is amazing that these guys cannot tolerate even one scientist working on a different avenue… frightening totalitarians.
Antonio San says:
Your comment is awaiting moderation.
9 October 2009 at 1:16 PM
Meanwhile Willard Boyle, 2009 Physics Nobel Prize winner -a scientific award, not the political one…- described his days as a researcher for Bell labs, as the most exciting of his life… What is needed is “an appreciation for the free will, free spirit of scientists. Give them a chance to do the things they want to do.”
So Rasmus, who and in under what competence is to decide what Svenmark and/or others should research or not? You? How convenient!”
Does it really tell us anything different than the Scotese graph. Both T and CO2 are at geologically low levels.
http://www.geocraft.com/WVFossils/Carboniferous_climate.html
william (11:30:42) :
You stated:
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.
Where did you get that paving over 25% of the landmass? I have been looking for data of that type for a while now, and I would be interested in reviewing it.
For most of the last 800,000 years the Earth has been frozen in the deepest Ice Age in 250 million years. The global climate has not been anywhere close to “normal” but has been locked in ice and tundra over two-thirds of the Northern Hemisphere. Short, 10,000-year-long interglacial warmings every 100,000 years are frankly inadequate respites from the Reign of Ice.
The data in this study are from one the most inhospitable eras ever for Life. Over a quarter of the globe has been rendered biologically inert (most of the time). If CO2 had anything to do with it, then the CO2 levels have obviously (biologically, practically, ethically) been too low.
Life florished globally during the Miocene. The Earth was a bountiful garden with huge biodiversity of plants and animals including unimaginable (today) features such as boreal tropical forests.
Warmer is Better. Most people live where it’s warmer. Almost all foods grow better where it’s warmer. Biodiversity is highest where it’s warmer — there are more species per acre in Equatorial regions and progressively less toward the poles. Warmer means more evaporation and hence more precipitation — the Ice Ages have been a 2.5 million-year-long drought compared to the norm of geologic history.
I doubt CO2 has much effect on climate, based on my reading of various studies highlighted at WUWT. But I wish it did. I have no problem with turning up the thermostat to Miocene levels. It’s not going to happen, because the Ice Ages are due to plate tectonics (Antarctica over the S. Pole). But if we could do something to raise the temp a few degrees, then we should do so, and be industrious, happy, and thankful about it.