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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super critical (11:21:32) :
“I should like to propose an alternative interpretation; that the data reflects an absolute decrease in atmospheric O2.”
When we give the results of chemical analysis, it is always on a percent concentration basis (per mass or volume) of the total (100%), the total mass from which the sample comes is practically irrelevant. So when CO2 concentrations increase, it does indeed mean that atmospheric free oxygen had to have also decreased by the amount of O2 in the new CO2, assuming, of course, that all of the O2 for the combustion came from the atmosphere. In the case of burning hydrocarbons, this is almost always true. It is interesting to note that the H also bonds with O2. At the same time, the entire mass of the atmosphere is increasing, but only by the mass of the additional C & H atoms. Obviously, the extra H2O produced does not stay in the atmosphere very long, and in any case the amount is nearly null compared to the amount of water already on the surface of the planet (as is also the case of CO2 vs the total atmosphere). It is also interesting to note that the C & H atoms involved have not seen the light of day, so to speak, for a very long time, but they were also part of the atmosphere at SOME point in the distant past.
As for the ice core records, most people do not realize this, but CO2 is the only atmospheric constituent for which special sampling procedures have been developed. To quote from the abstract of the description of a newly developed dry extraction technique, this is because of the “well known water artifacts” when testing for CO2. Yes, I, for one, DO well know what the “artifacts” are when the ice starts to melt – higher concentrations of CO2. In other words, unless those results are being compared to “snowball earth”, they are totally invalid, and certainly not comparable to measurements taken in the tropics.
Jim Carson (12:49:33) :
And from 1880 to present, a sea level rise of about ten inches is associated with an increase in carbon dioxide levels of about 100 parts per million, i.e. chump change.
That made my friday! LOL
william 11:30:42
I’m interested in your claim that over 25% of the landmass of the planet is paved. Do you have any sources for this statement?
hippie longstocking said:
I think Dr. Dean Edell summed up a ‘link’ the best when he said “You can link french fries with car accidents if you want, but you’ll never be able to prove they cause them.”
That explains it. I was recently at a salvage yard pulling parts off a vehicle. It had been T-boned and I was wondering why there were french fries on the seat!
25% paved? Good lord, someone needs to get outside the city once in a while.
According to National Geographics, in the continental US, 20% of land mass is within 500 meters of a paved road. Within 500 meters!!! In the continental US!!! Add Alaska in and that number plummets.
What fraction of 1% do you think that number would be for Africa, China, South America.
25%… please.
I think you all are missing the point, the new method they used to measure CO2 demonstrates that the last time CO2 levels were as high as they are now was 15 million years ago. There’s not much controversial about that. How the climate has changed over that 15 million years was not the scope of her analysis. It make take decades for increased CO2 levels to build up the inertia (perhaps by warming the oceans) to bump up Global temps by 3-5C. Why do you all expect the earth to respond instantly to that change?
You also cannot produce a reputable scientist that will disagree with the statement that increasing CO2 levels will increase temperatures. It’s not even arguable as even people like Spencer and Lucia will agree. The only issue is how much temperature will go up and how fast based on what level of CO2. After that we don’t know exactly what will happen but scientists are pointing things that may happen like: ice melting, sea level rising, species going extinct, water shortages, heat waves, droughts, forest fires.
We can wish and believe that increasing CO2 levels will not be a problem or we can take some kind of action based on a reasonable amount of information that perhaps it’s not a good thing for the planet for us to pump all that CO2 into the atmo. Based on the responses on this thread it sounds like all of you would have also been skeptical of the studies showing damage caused to the ozone by CFC’s. Thank god scientists recognized the problem and politicians listended and took action. If they had not , our kids would not be able to play outside unless they wore sun block level 1000.
So what will it be, ignore the possibility that gigatons of CO2 added to the atmo every year is a problem or take some kind of reasonable preventive action to prevent some or all of the potential consequences that scientists are pointing out?
Shiney
William
The hockey stick (shown above) does not appear anywhere in the paper. I’d guess someone at UCLA news borrowed it from Wikipedia, or IPCC.
However, I was appalled to find
“These results show that changes in pCO2 and climate have
been coupled during major glacial transitions of the past 20
myr, just as they have been over the last 0.8 myr, supporting
the hypothesis that greenhouse gas forcing was an important
modulator of climate over this interval via direct and indirect
effects. Variations in pCO2 affect the radiative budget and
energy balance of the planet.”
When the graphs included had too few data points to determine whether temperature of CO2 leads:
“The data presented do not preclude alternative
mechanisms for driving climate change over the past 20 Ma;”
It is not CO2 but H2O that is driving climate change today.We are being told that we must make changes in our lifestyles because of what climate models predict will happen in the future and ignore reality, no.
anna v says:
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.
william (13:47:07) :
I think you all are missing the point
No, you sir are missing the point.
The point is NONE of the published science has provided anything that could be called a “reasonable amount of information that perhaps it’s not a good thing for the planet for us to pump all that CO2 into the atmo”
Do you hear me – NONE – not even ONE research paper – NONE! It is bogus nonsense.
If you understood atmospheric physics then you would know the difference between a simplistic computer model and the complexities of real world systems.
If you understood atmospheric physics then you would know that water vapor is TWENTY times more potent than CO2 and you would know that CLOUD COVER is VASTLY more important than CO2.
I know Sir that you mean well but are you even aware of the IMPACT of cutting back fossil fuels on food production, health and living standards…do you understand how completely UNREASONABLE it is to even suggest to go back to CO2 levels of 10 or 20 years ago – “because perhaps it’s not a good thing for the planet” – this line of thought is totally INSANE.
steve and tellboy
You need to do some reading over at http://pielkeclimatesci.wordpress.com/ and yes I mispoke I should have said man has altered significantly 25% of the surface of the earth on the way towards 50%. If you disagree with the effects that can have on climate then take it up with Peilke Sr and the hundreds of studies he’s highlighted on his blog.
And by the way I do get out of the city and all I see are shopping malls and commercial buildings going up where cornfields used to be. Oops those cornfields used to be natural prairies that covered the Midwestern United states, except they don’t exist anymore as they been ploughed under. Remember the dust bowl?
Increased CO2 = higher temperatures. Please provided the name of one reputable scientist that disagrees with that. Even McIntyre and McKitrick do not argue with AGW on first principles. It’s because it’s not arguable.
Shiny
William
What caused the large spike in CO2 in the 24-25 million year range?
William,
Actually, as I just pointed out in response to a question above, the added “gigatons” need to be reduced by the mass of the O2 in those new CO2 molecules, the O2 was already present in the atmosphere, as well as reducing it by the additional mass of O2 tied up as new water molecules. Please recalculate your results with these new assumptions, the previous results are not quite correct.
The new study in question is intimately tied to ice core measurements, which are very questionable.
Are you a “reputable scientist”?
Obama gets the Nobel Peace Prize, like Al Gore, now he must do something for “Climate Change” like legislate poverty even faster, and reach out to people who seek violent world domination.
First of all, I’m a skeptic…of ALL things designed to exatrct money from me! So that means I’m an AGW skeptic.
That said, the so-called geologists on here stating (paraphrased): “Yeah, we had high CO2 in the past…what caused those?”
Even if we knew, those reasons would NOT disprove AGW as ANOTHER cause.
I like anna’s approach a lot better: Attacking the SCIENCE in these articles; attacking the SCIENTIFIC METHOD (ie, NOT being used)
There should be a rule about posting on here: You’re not allowed to criticize a pro-AGW article unless you provide scientific proof that counters it, or you spell out what’s wrong with the methodology.
The article’s hockey stick might be completely valid! And it wouldn’t prove or disprove a thing!!! (except that the author is capable of using a chart program)
Unfortunately, it’s just too easy to see the apparent rise around the 1800s, and connect that to the industrial revolution. It’s natural to do that. But it’s SUPPOSED to be natural to ask “Is there really a cause?”
william (13:47:07)…
…is the guy who claims that 25% of the planet is paved [Earth’s land mass = ≈57 million square miles], thinks we’re all missing the point. He says that geological CO2 measurements are not controversial [?!?]. Maybe reading this thread would convince him otherwise… and maybe not.
william also claims that no ‘reputable’ scientist disagrees that CO2 causes warming. Again, he should follow this thread and links. He would find out that he isn’t even asking the right question. Feedbacks and the sensitivity number are what matters.
I won’t even go into the appeals to authority and other illegitimate arguments william repeats. Someone else should have the opportunity to have some fun, too. Especially after the crazy talk about a quarter of the Earth’s land mass being paved.
C’mon, admit it, william. You’re a RC refugee, aren’t you?
I think this response should be noted! It’s by a retired Scientist, Fred H. Haynie, who took time to reseach AGW. This is what he found! He has a very interesting research from the results of Ice Cores!
http://www.kidswincom.net/climate.pdf
You can see my article here: http://www.globalwarminghoax.com/e107_plugins/forum/forum_viewtopic.php?1038
Mr. Haynie is looking for some Scientists to review his work! I hope someone here can get ahold of Him and help!
Robert M. (11:34:57)
I agree it looks baseless. What looks interesting is the disparety between this work and Bill Illis’s sources. More of a chasm than a disparity
I just did a google “Aradhna Tripati UCLA”, as already predicted this article has been rapidly published – 7 google pages worth of hits already!
This young geologist is going places – a promotion is surely coming soon! I sense a high level position on Government Science Committees too.
Jeremy
I’ve read everything on Spencer’s site and he would tell you that the statements in your comment do not describe the real world. Its a fact that water vapor and clouds impact temperatures but your willingness to believe in their effect on climate and disbelief that CO2 also has an effect speaks volumes for your lack of understanding about this topic.
You’d be startled on my suggestions to improve our situation, but the fact that it will be painful to fix does not mean you ignore the problem. If we had chosen to continue to pump out CFC’s until we destroyed the ozone layer completely would that have been a good thing? Life is full of hard choices and a responsible society does not kick problems down the road for their children to solve.
Oh I forgot, the USA does kick problems down the road. I forgot about the mortgage crisis, the backruptcy of Social Security, the huge liabilities of Medicare and Medicaid and trillions in debt our children will have to pay off. I guess for an irresponsible society like the old USA changing our CO2 habits is just too hard! It won’t matter in the long run as China will own the USA soon and there will not be need to have industries polluting our skies anymore.
Shiny
William
And that is automatically a bad thing? Insects have “altered” pretty much 100% of the land surface. So have nematodes. But if it is “altered” by a non-human life form, then I suppose that is ok and “natural” whereas humans are not “natural” and any “alteration” caused by us is bad?
A being “alters” anyplace it exists. Any place it excretes waste is altered, the atmosphere that it breathes is “altered” any place it puts its foot is “altered” and anywhere it disturbs a plant or animal for food is “altered”.
Lets not forget that much of this “alteration” as allowed for much greater food consumption or health conditions. The condition of the human being was much worse only a couple of hundred years ago. During the Roman Empire, 85% of the people born did not make it to 35 years of age. That number didn’t change much until the early 1800’s.
Due to this “alteration” we have meat and a wide variety of vegetables to eat year round. Back in those days human diet was much worse and health was much worse. You ate only what grew in your local area when it was in season. There was no such thing as long term preservation such as canning or freezing of foods.
What tickles me most is when I hear a vegan talking about how bad our ecosystem is. They have the most unsustainable lifestyle there is and if it wasn’t for a system that uses a tremendous amount of energy to transport fresh veggies to them from around the world, they would be outside eating bark in the winter and would starve to death.
Sure, take things back to the way they were in the 18th century. Most of us would never live to see our 25th birthday. Some life that is. Yeah, we wouldn’t have much cancer and heart disease because we would die from something else much sooner.
“What caused the large spike in CO2 in the 24-25 million year range?”
Oligocene SUVs didn’t you know?
Lashaffer and Smokey
I’m actually a climate skeptic and view the people who post at RC as those who worship on the altar of AGW. I consider myself a “warmer” and my views are consistent with Dr. Roy Spencer who also believes that increased CO2 causes warming. How much warming and understanding clouds and whether they are a +/- feedback is really the issue at this point. I find most of the comments here to be very similiar to those at RC in that you are at “polar” extremes on the topic as “deniers” of the possibility of AGW. I feel the truth is somewhere in the middle as Dr. Spencer does.
Shiny
William
I have a quick question. If the temps were 5 to 10 degrees warmer than today if the same amount of CO2, then why aren’t the temps 5 to 10 degrees warmer if CO2 is a climate driver?
Okay, here’s my problem. We’re fairly sure the Midieval, and the Roman Warm Periods were as Warm, if not warmer, than the present, right?
Then shouldn’t the CO2 levels, due to out-gassing from the warmer oceans, be about the same? Wattsupwiththat?