Guest Post by Willis Eschenbach
There seem to be a host of people out there who want to discuss whether humanoids are responsible for the post ~1850 rise in the amount of CO2. People seem madly passionate about this question. So I figure I’ll deal with it by employing the method I used in the 1960s to fire off dynamite shots when I was in the road-building game … light the fuse, and run like hell …
First, the data, as far as it is known. What we have to play with are several lines of evidence, some of which are solid, and some not so solid. These break into three groups: data about the atmospheric levels, data about the emissions, and data about the isotopes.
The most solid of the atmospheric data, as we have been discussing, is the Mauna Loa CO2 data. This in turn is well supported by the ice core data. Here’s what they look like for the last thousand years:
Figure 1. Mauna Loa CO2 data (orange circles), and CO2 data from 8 separate ice cores. Fuji ice core data is analyzed by two methods (wet and dry). Siple ice core data is analyzed by two different groups (Friedli et al., and Neftel et al.). You can see why Michael Mann is madly desirous of establishing the temperature hockeystick … otherwise, he has to explain the Medieval Warm Period without recourse to CO2. Photo shows the outside of the WAIS ice core drilling shed.
So here’s the battle plan:
I’m going to lay out and discuss the data and the major issues as I understand them, and tell you what I think. Then y’all can pick it all apart. Let me preface this by saying that I do think that the recent increase in CO2 levels is due to human activities.
Issue 1. The shape of the historical record.
I will start with Figure 1. As you can see, there is excellent agreement between the eight different ice cores, including the different methods and different analysts for two of the cores. There is also excellent agreement between the ice cores and the Mauna Loa data. Perhaps the agreement is coincidence. Perhaps it is conspiracy. Perhaps it is simple error. Me, I think it represents a good estimate of the historical background CO2 record.
So if you are going to believe that this is not a result of human activities, it would help to answer the question of what else might have that effect. It is not necessary to provide an alternative hypothesis if you disbelieve that humans are the cause … but it would help your case. Me, I can’t think of any obvious other explanation for that precipitous recent rise.
Issue 2. Emissions versus Atmospheric Levels and Sequestration
There are a couple of datasets that give us amounts of CO2 emissions from human activities. The first is the CDIAC emissions dataset. This gives the annual emissions (as tonnes of carbon, not CO2) separately for fossil fuel gas, liquids, and solids. It also gives the amounts for cement production and gas flaring.
The second dataset is much less accurate. It is an estimate of the emissions from changes in land use and land cover, or “LU/LC” as it is known … what is a science if it doesn’t have acronyms? The most comprehensive dataset I’ve found for this is the Houghton dataset. Here are the emissions as shown by those two datasets:
Figure 2. Anthropogenic (human-caused) emissions from fossil fuel burning and cement manufacture (blue line), land use/land cover (LU/LC) changes (white line), and the total of the two (red line).
While this is informative, and looks somewhat like the change in atmospheric CO2, we need something to compare the two directly. The magic number to do this is the number of gigatonnes (billions of tonnes, 1 * 10^9) of carbon that it takes to change the atmospheric CO2 concentration by 1 ppmv. This turns out to be 2.13 gigatonnes of carbon (C) per 1 ppmv.
Using that relationship, we can compare emissions and atmospheric CO2 directly. Figure 3 looks at the cumulative emissions since 1850, along with the atmospheric changes (converted from ppmv to gigatonnes C). When we do so, we see an interesting relationship. Not all of the emitted CO2 ends up in the atmosphere. Some is sequestered (absorbed) by the natural systems of the earth.
Figure 3. Total emissions (fossil, cement, & LU/LC), amount remaining in the atmosphere, and amount sequestered.
Here we see that not all of the carbon that is emitted (in the form of CO2) remains in the atmosphere. Some is absorbed by some combination of the ocean, the biosphere, and the land. How are we to understand this?
To do so, we need to consider a couple of often conflated measurements. One is the residence time of CO2. This is the amount of time that the average CO2 molecule stays in the atmosphere. It can be calculated in a couple of ways, and is likely about 6–8 years.
The other measure, often confused with the first, is the half-life, or alternately the e-folding time of CO2. Suppose we put a pulse of CO2 into an atmospheric system which is at some kind of equilibrium. The pulse will slowly decay, and after a certain time, the system will return to equilibrium. This is called “exponential decay”, since a certain percentage of the excess is removed each year. The strength of the exponential decay is usually measured as the amount of time it takes for the pulse to decay to half its original value (half-life) or to 1/e (0.37) of its original value (e-folding time). The length of this decay (half-life or e-folding time) is much more difficult to calculate than the residence time. The IPCC says it is somewhere between 90 and 200 years. I say it is much less, as does Jacobson.
Now, how can we determine if it is actually the case that we are looking at exponential decay of the added CO2? One way is to compare it to what a calculated exponential decay would look like. Here’s the result, using an e-folding time of 31 years:
Figure 4. Total cumulative emissions (fossil, cement, & LU/LC), cumulative amount remaining in the atmosphere, and cumulative amount sequestered. Calculated sequestered amount (yellow line) and calculated airborne amount (black) are shown as well.
As you can see, the assumption of exponential decay fits the observed data quite well, supporting the idea that the excess atmospheric carbon is indeed from human activities.
Issue 3. 12C and 13C carbon isotopes
Carbon has a couple of natural isotopes, 12C and 13C. 12C is lighter than 13C. Plants preferentially use the lighter isotope (12C). As a result, plant derived materials (including fossil fuels) have a lower amount of 13C with respect to 12C (a lower 13C/12C ratio).
It is claimed (I have not looked very deeply into this) that since about 1850 the amount of 12C in the atmosphere has been increasing. There are several lines of evidence for this: 13C/12C ratios in tree rings, 13C/12C ratios in the ocean, and 13C/12C ratios in sponges. Together, they suggest that the cause of the post 1850 CO2 rise is fossil fuel burning.
However, there are problems with this. For example, here is a Nature article called “Problems in interpreting tree-ring δ 13C records”. The abstract says (emphasis mine):
THE stable carbon isotopic (13C/12C) record of twentieth-century tree rings has been examined1-3 for evidence of the effects of the input of isotopically lighter fossil fuel CO2 (δ 13C~-25‰ relative to the primary PDB standard4), since the onset of major fossil fuel combustion during the mid-nineteenth century, on the 13C/12C ratio of atmospheric CO2(δ 13C~-7‰), which is assimilated by trees by photosynthesis. The decline in δ13C up to 1930 observed in several series of tree-ring measurements has exceeded that anticipated from the input of fossil fuel CO2 to the atmosphere, leading to suggestions of an additional input ‰) during the late nineteenth/early twentieth century. Stuiver has suggested that a lowering of atmospheric δ 13C of 0.7‰, from 1860 to 1930 over and above that due to fossil fuel CO2 can be attributed to a net biospheric CO2 (δ 13C~-25‰) release comparable, in fact, to the total fossil fuel CO2 flux from 1850 to 1970. If information about the role of the biosphere as a source of or a sink for CO2 in the recent past can be derived from tree-ring 13C/12C data it could prove useful in evaluating the response of the whole dynamic carbon cycle to increasing input of fossil fuel CO2 and thus in predicting potential climatic change through the greenhouse effect of resultant atmospheric CO2 concentrations. I report here the trend (Fig. 1a) in whole wood δ 13C from 1883 to 1968 for tree rings of an American elm, grown in a non-forest environment at sea level in Falmouth, Cape Cod, Massachusetts (41°34’N, 70°38’W) on the northeastern coast of the US. Examination of the δ 13C trends in the light of various potential influences demonstrates the difficulty of attributing fluctuations in 13C/12C ratios to a unique cause and suggests that comparison of pre-1850 ratios with temperature records could aid resolution of perturbatory parameters in the twentieth century.
This isotopic line of argument seems like the weakest one to me. The total flux of carbon through the atmosphere is about 211 gigtonnes plus the human contribution. This means that the human contribution to the atmospheric flux ranged from ~2.7% in 1978 to 4% in 2008. During that time, the average of the 11 NOAA measuring stations value for the 13C/12C ratio decreased by -0.7 per mil.
Now, the atmosphere has ~ -7 per mil 13C/12C. Given that, for the amount of CO2 added to the atmosphere to cause a 0.7 mil drop, the added CO2 would need to have had a 13C/12C of around -60 per mil.
But fossil fuels in the current mix have a 13C/12C ration of ~ -28 per mil, only about half of that requried to make such a change. So it is clear that the fossil fuel burning is not the sole cause of the change in the atmospheric 13C/12C ratio. Note that this is the same finding as in the Nature article.
In addition, from an examination of the year-by-year changes it is obvious that there are other large scale effects on the global 13C/12C ratio. From 1984 to 1986, it increased by 0.03 per mil. From ’86 to ’89, it decreased by -0.2. And from ’89 to ’92, it didn’t change at all. Why?
However, at least the sign of the change in atmospheric 13C/12C ratio (decreasing) is in agreement with with theory that at least part of it is from anthropogenic CO2 production from fossil fuel burning.
CONCLUSION
As I said, I think that the preponderance of evidence shows that humans are the main cause of the increase in atmospheric CO2. It is unlikely that the change in CO2 is from the overall temperature increase. During the ice age to interglacial transitions, on average a change of 7°C led to a doubling of CO2. We have seen about a tenth of that change (0.7°C) since 1850, so we’d expect a CO2 change from temperature alone of only about 20 ppmv.
Given all of the issues discussed above, I say humans are responsible for the change in atmospheric CO2 … but obviously, for lots of people, YMMV. Also, please be aware that I don’t think that the change in CO2 will make any meaningful difference to the temperature, for reasons that I explain here.
So having taken a look at the data, we have finally arrived at …
RULES FOR THE DISCUSSION OF ATTRIBUTION OF THE CO2 RISE
1. Numbers trump assertions. If you don’t provide numbers, you won’t get much traction.
2. Ad hominems are meaningless. Saying that some scientist is funded by big oil, or is a member of Greenpeace, or is a geologist rather than an atmospheric physicist, is meaningless. What is important is whether what they say is true or not. Focus on the claims and their veracity, not on the sources of the claims. Sources mean nothing.
3. Appeals to authority are equally meaningless. Who cares what the 12-member Board of the National Academy of Sciences says? Science isn’t run by a vote … thank goodness.
4. Make your cites specific. “The IPCC says …” is useless. “Chapter 7 of the IPCC AR4 says …” is useless. Cite us chapter and verse, specify page and paragraph. I don’t want to have to dig through an entire paper or an IPCC chapter to guess at which one line you are talking about.
5. QUOTE WHAT YOU DISAGREE WITH!!! I can’t stress this enough. Far too often, people attack something that another person hasn’t said. Quote their words, the exact words you think are mistaken, so we can all see if you have understood what they are saying.
6. NO PERSONAL ATTACKS!!! Repeat after me. No personal attacks. No “only a fool would believe …”. No “Are you crazy?”. No speculation about a person’s motives. No “deniers”, no “warmists”, no “econazis”, none of the above. Play nice.
OK, countdown to mayhem in 3, 2, 1 … I’m outta here.
Willis,
IMHO you need to divide the atmosphere into two parts. The part where liquid water exists, and the part where it does not. The dwell time of a soluble gas in a rain storm is going to be radically different from its dwell time over a frozen pole.
Dirk H – Willis’s wording was very poor I see the residence time is a different length of time than the e-folding but the plot of the quantity of CO2 wrt time for a pulse of CO2 released is the same so why confuse the issue, the concept of the time required for the pulse to reduce to 50% (residence time) is much more comprehensible. Half life in nuclear terminology is the same value i.e. time to reach 50% of the original activity level so we have a conflict of terms in different technologies or Willis is confusing half life with e-folding which are different values.
Phlogiston – gasses are very different to liquids, the law of partial pressures applies so gasses do not separate according to density.
Arfur you did acknowledge H2O at the end of your post. H2O is by far the most powerful so called GG but it varies from 35ppm at –60 in the polar regions to 40 000 ppm at the tropics where is the tipping point you might ask good question there is not one.
Bjorn take a look at the CO2 record “ exponential increase ?” please check your dictionary.
For those interested in actual science not manipulated cherry picked statistics from dubious proxies try John Nicols paper which is a true scientific evaluation based on the laws of physics of the so called greenhouse gas effect.
The stomata proxy is very robust and has been verified by data from 1952 to 1995 correlating stomata configurations with actual measured CO2 levels. Unlike the tree ring farce.
Malaga View says:
June 7, 2010 at 12:52 pm
The Real Co2 site by Ernst-Georg Beck is very interesting:
http://www.biomind.de/realCO2/realCO2-1.htm
Especially the Atmospheric CO2 Background 1826-1960 diagram:
http://www.biomind.de/realCO2/bilder/CO2back1826-1960eorevk.jpg
Seems a lot more natural and believable than the ice core flat lining….
So a drop of ~80 ppm in a few years around 194o is believable is it?
An earlier poster said:
“Warming oceans. Natural warming of the ocean releases dissolved CO2 like a glass of beer.”
and Willis replied:
“Again, I discuss this in the head post, and it is not large enough to cause the recent rise either.”
Willis,
On a year to year basis the Mauna Loa changes are pretty small and could well be explained by variations in oceanic CO2 absorption rates.
Only if one looks at the entire post 1850 rise as a single block does it seem unlikely that the oceans are a big enough contributor to the whole observed change.
However that could be explained by the discontinuity issue whereby a proxy that fails to recognise the signals of the MWP and LIA is grafted onto the far more sensitive modern day methods which clearly would have been sensitive enough to recognise the MWP and LIA.
Thus the oceans could indeed be responsible.
phlogiston says:
June 7, 2010 at 2:13 pm
Not so – residence time is half life / ln 2 (which is 0.693). Thus t1/2 is a bit shorter than residence time (tau).
There might be some confusion over the definition of ‘residence time’ here. I think Willis is referring to the average lifetime (residence time) of a CO2 molecule in the atmosphere. This is only a few years. However, this is not the same thing as the time taken for a pulse of CO2 to be removed from the atmosphere. In this case, both the half-life and e-folding time are much longer.
Gail:
Here is the direct answer to your question from the good scientists at Scripps Oceanographic:
AHN Jinho (1 2) ; HEADLY Melissa (1) ; WAHLEN Martin (1) ; BROOK Edward J. (2) ; MAYEWSKI Paul A. (3) ; TAYLOR Kendrick C. (4) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Scripps Institution of Oceanography, University of California-San Diego, La Jolla, California 92093-0225, ETATS-UNIS
(2) Department of Geosciences, Oregon State University, Corvallis, Oregon 97331-5506, ETATS-UNIS
(3) Climate Change Institute, University of Maine, 303 Bryand Global Sciences Center, Orono, Maine 04469-5790, ETATS-UNIS
(4) Desert Research Institute, University of Nevada, 2215 Raggio Parkway, Reno, Nevada 89512-1095, ETATS-UNIS
Résumé / Abstract
One common assumption in interpreting ice-core CO2 records is that diffusion in the ice does not affect the concentration profile. However, this assumption remains untested because the extremely small CO2 diffusion coefficient in ice has not been accurately determined in the laboratory. In this study we take advantage of high levels of CO2 associated with refrozen layers in an ice core from Siple Dome, Antarctica, to study CO2 diffusion rates. We use noble gases (Xe/Ar and Kr/Ar), electrical conductivity and Ca2+ ion concentrations to show that substantial CO2 diffusion may occur in ice on timescales of thousands of years. We estimate the permeation coefficient for CO2 in ice is ∼4 x 10-21 mol m-1 s-1 Pa-1 at -23°C in the top 287m (corresponding to 2.74 kyr). Smoothing of the CO2 record by diffusion at this depth/age is one or two orders of magnitude smaller than the smoothing in the firn. However, simulations for depths of ∼930-950 m (∼60-70 kyr) indicate that smoothing of the CO2 record by diffusion in deep ice is comparable to smoothing in the firn. Other types of diffusion (e.g. via liquid in ice grain boundaries or veins) may also be important but their influence has not been quantified.
Gail, your instincts are correct:
1) All CO2 analytical methods, wet or dry give close results, they are precise methods
2) Of course, the diffusion calculated for Scripps for CO2 shows that all results are “smoothed”, another word for equilibrated.
3) The results in hundreds or thousands of years will arrive, by Fick’s Laws to the same average ambient level for that time period.
Given enough time, from the Scripps results, probably in less than over a hundred year span, ice under a thousand meters thick will behave as if on the surface, and will equilibrate to the atmospheric level in an asymptotic fashion.
Bottom line: If CO2 is constant in the atmosphere, at 300-400 ppm over the last hundreds of years, all of the cores of the last 10,000 years will show a similar quantitative result for CO2 concentration regardless of what the concentration was at the time the CO2 was incorporated, approaching asymptotically 300-400 ppm.
I have a few questions for Willis regarding CO2 and temperature.
1) Is he aware of any other CO2 measurement stations besides Mauna Loa (which sits atop the world’s largest active volcano surrounded by the world’s largest CO2 emitting ocean)?
2) Shouldn’t the summary findings of Beck 2007 of 90,000 CO2 measurements taken by hundreds of scientists during the last 200 years be taken into consideration?
3) What is the explanation for CO2 increases lagging by about 800 years the temperature increases documented in ice core records?
4) Why is there no correlation between the Scotese temperature data and Berner CO2 data for the last 600 million years?
“Statement of Prof. Zbigniew Jaworowski
Chairman, Scientific Council of Central Laboratory for Radiological Protection
Warsaw, Poland
….The problem with Siple data (and with other shallow cores) is that the CO2 concentration found in pre-industrial ice from a depth of 68 meters (i.e. above the depth of clathrate formation) was “too high”. This ice was deposited in 1890 AD, and the CO2 concentration was 328 ppmv, not about 290 ppmv, as needed by man-made warming hypothesis…….”
______________________________________________________________________
HMMMmmmm 328ppm CO2 for the year 1890.
I cross checked that against the detailed scientific examination of historic CO2 measurements by Ernst Beck and it is within his margin of error. http://www.biomind.de/realCO2/
I then went to Beck’s site: http://www.biokurs.de/eike/daten/leiden26607/leiden9e.htm
1883 – 266 sample with an average of 335 ppm
What is really really interesting is Barrow 1947-1948 data at 420 ppm! (average of 330 samples) It is noted that the Keeling samples (1972 to 2004) are transported from Barrow Alaska to California before they are analysed. http://www.biokurs.de/eike/daten/leiden26607/leiden6e.htm
Willis,
I would like to ask how you performed the calculation to produce the Calculated Airborne line Figure 4. The proper way would be to perform a convolution of the emissions with an exponential weighting with time constant of 31 years. To get the endpoint, you would then have to extrapolate the emissions data forward. Or, did you just scale it somehow?
I would also like to know more about the source of the “emissions” data. I have an extremely tough time believing we have anything like an accurate measure of worldwide emissions stretching back to 1850. Is this really just tabulated data of things like fuel consumption and cement production scaled for their theoretical partial CO2 production based on the combustion technology of the time, or were there other assumptions or observation data blended in? You might consider showing a plot of the yearly differences (delta-production year-to-year) as this might more clearly show some blips which most of us would expect for, e.g., the WWII years.
Willis Eschenbach says:
June 7, 2010 at 12:59 pm
I thought my response to Dr. Ravetz was free of ad hominem attacks, but of course, YMMV.
Pick a post, any post…
Willis Eschenbach says:
February 15, 2010 at 7:15 pm
Ooooh, poor widdle baby Jerry, we insulted his cerebral sensitivities by calling him a big bad Marxist so he took his toys and went home …
Now, you claim that he “resigned from politics”, but he sure hasn’t resigned from Marxism …
Scientific debate is so edificatory innit?
😉
For all those people who are taken in by the Willis smoke and mirrors dog and pony show I sincerely hope you will remember these days when Obama inflicts his carbon tax on you indirectly via the energy companies and has poured billions into totally uneconomical white elephants called renewable energy projects. This will cost jobs and cripple an already staggering economy.
The alternative is quite simple assume the worst, global warming is an unstoppable natural cycle, so let us mitigate against it. Rising sea levels at 25 cm per century? we can built sea walls to protect low lying areas, the Dutch have been doing it for centuries. Droughts and floods, computer models show in a warmer world 10% will have less rain and soil moisture 90% more so let us build irrigation systems and flood control systems.
This will create useful jobs and whatever happens will increase our productivity.
The current CO2 reduction proposals will have absolutely no effect on the CO2 levels and cause a negative economic impact of the average taxpayer of between $2500 and $3000 per year.
People talk glibly of doubling the CO2 level, where on earth is the 860 GT of carbon going to come from to double the CO2 level, not from humans that’s for sure.
In the last 500 million years CO2 levels have been excess of 1000 ppm for 80% of the time and there were no tipping points or disasters this is absolute nonsense.
Realistically what does the future hold for the climate, we are is the worst solar minimum for over 100 years with no end in sight the PDO an AMO have swung into a cold phase which according to historical records could last 40 years, according to the Argo float buoy data the oceans are cooling down, according to satellite data the troposphere is not performing anything like the IPCC computer programs predicted. All the indications are that we have peaked out of the 20th century warm period and we are heading into a down period but there is no guarantee of this so the mitigation actions as well as research into an economical sustainable energy supply should proceed.
So please let us stop running around like chickens with our heads cut off at get down to some logical, cost effective, long term planning.
Smokey @11:23
I haven’t got to it yet, but I would like to look at the ~11 year cycles of the charts I pasted. I would add a 8-12 year band-pass filter to the ~40 year low pass, and see how it would compare to the irradiance graph..
Prior to 1800, on the graphs, all temp records were from Europe. It is only about 1850, that a few non-European records show appear. So by 1900 onward, the shape begins to approach the Hadcet shape.
I am going to lob a hand grenade into this, just to see what comes of it:
Nixon. China. 1972.
1976: Mao and Chou En Lai both die, opening the door to some level of capitalism in China. This will take a few years to take seed.
Early 1980s: US starts trade missions in China. This accelerates in the 1980s. US begins the era of the maquiladores, US companies operating just across the Rio Grande in northern Mexico.
1990s: Full-fledged flow of manufacturing out of the US to Mexico and increasingly to China. Jobs off-shored to Mexico begin moving to China. China’s population begins to become consumers, vastly increasing the market for Chinese goods, many of which used to be US goods.
What is the tie-in with the CO2 hickey stick?
Poorer regulation of emissions of all sorts in Mexico and China versus the US. What used to be produced in a country with emissions standards was – in not much more than a decade – produced in countries with much lower standards.
In addition: I traveled in Europe in the early to mid-1970s, and the level of prosperity there was a long way short of the US. By the 1990s, that had leveled off, and now Europe has passed the US in many ways. Translation: A much larger market for goods from all sources – just as the Chinese were assuming the role as the manufacturing for the world.
Add in India, to boot, whose emissions standards were quite a bit below US and European standards.
Larger markets (don’t forget the non-Chinese Asian market, either), manufacturing under less stringent regulations – it was all happening at the same time the CO2 began climbing.
We all know that since the 1970 Clean Air & Water Act the US’s air has been cleaned up immensely. We don’t seem to credit the degree that manufacturing is NOT done here anymore. Off the top of my head, I would say our air is cleaner than it was in 1990, and 1990 was cleaner than 1980. America IS cleaning up its act – by shipping so many jobs overseas, mostly to Mexico, China and India.
Is it coincidence that China becoming the industrial park of the world, with little controls, just when all those curves start climbing? Or is there linkage there?
I suspect linkage.
Charles S. Opalek, PE says:
June 7, 2010 at 3:47 pm
Both of these are discussed at length in my post “Under the Volcano, Over the Volcano“.
Haven’t a clue.
Because CO2 doesn’t rule the temperature. See my post here that discusses this question.
Willis has done an admiral job.
He has effectively summarized that CO2 concentration is decoupled from temperature, as least in a positive sense. Many studies have shown that CO2 rises lag temperature increases. Of course, they are all by proxies.
However, he has insisted that CO2 measurements are rising. This is certainly equivocal, but it gives support to one facet of the warm-earthers’ argument.
But remember, all facets of the alarmists’ argument must be true for any action to be warranted:
1) CO2 current levels and rate of rise must be unprecedented in recent historic times
2) CO2 rise, if unprecedented, must be anthropogenic, due to industrial burning of “fossil fuels”
3) CO2 anthropogenic rise must dwarf other natural sources
4) The earth’s average temperature must be rising without precedent in historic times
5) CO2 rise must be causative of current higher earth temperatures, correlating strongly with higher temperatures as CO2 goes higher, not the other way around
6) The temperature record must be accurate and free from introduced or systematic bias, and show an inexorable rise correlating with human CO2 emissions
So let’s not get caught up in one facet, CO2. For the alarmist cult to survive, all of the above have to be unequivocal and proven. The burden of proof is on the alarmist side, since they are advocating the Draconian measures.
Charles, a long time ago I did an analysis of CO2 readings from around the world NOAA has a excellent web site for this (iadv) by 1980 there were about 20 modern stations covering the entire globe the number has increased considerably since then. Net result the annual average of CO2 is very close (2ppm) between the northern and southern hemispheres. The north exhibts a sigificant annual cycle due to seasonal vegitation the south virtually none, indicating very little mixing of the air masses between the hemisphere tropospheres. In actual fact the SH has a higher level of CO2 for 5 months so mixing is academic however 94% of anthropogenic CO2 is released in the NH and 6% in the south even with a 3 year mixing tme the NH should be at least 20ppm higher than the south.
It seems Michael Mann-erisms are catching … mixing data from markedly different sources to create hockey sticks.
What is the basis for the assumption that air surrounded by ice is any more a closed system than air in a balloon ? Why should air in ice be immune from diffusion and dissolution ?
We know that oceans emit and absorb 20 times as much CO2 as man. We know that rising temperatures cause CO2 in the atmosphere to increase. We would hence expect ice core records to show rising atmospheric CO2 levels during the MWP and falling levels during the LIA … however we get a horizontal line !
I think that data from nature showing horizontal lines with no variation is suspect, as it was with Mann’s hockey stick. In this case ice core data showing no variation, indicates some form of long term averaging, such as by gas in ice diffusion. We would expect more recent ice core data to curve up to meet current levels, again through diffusion.
Bart says:
June 7, 2010 at 4:02 pm
I set up the equation based on a percentage drop P, which is the percentage of the “excess” CO2 that is not sequestered every year. So if year zero has an airborne C of X gigatonnes, and an emission of E gigatonnes, then year one has an airborne C of (X + E) * P.
So I do that calculation with an arbitrary “P” for each year of the entire dataset. I started with P at about .975. This gives me a calculated value for each year. Then I iteratively adjust “P” until it gives me the best match (lowest RMS error) to the data. I use the Excel “Solver” function to do the iteration, but it could be done by hand (only slower). That gives me the best value for P.
Then I use P to calculate either the half-life or the e-folding time as desired. Given P, the half-life H is P ^ H = 0.5. Solving this gives us H = log(0.5)/log(P). The calculation is similar for the e-folding time, using 0.37 instead of 0.5.
barry moore says:
June 7, 2010 at 4:05 pm
Barry, you don’t seem to have the slightest clue about my general take on the AGW hypothesis. Simply put, I think it is totally false. Your claims are both rude and meaningless, as they have nothing to do with what I think is happening with the climate. All you have done is made yourself look foolish. Like you, I totally oppose the “Cap ‘n Tax” proposed by Obama, I think it is a horrific plan. I absolutely think that the rise in CO2 is not responsible for the recent warming (or for the 1945-1970 cooling for that matter), I think the rise in CO2 is meaningless to the temperature. I’m just discussing the question of the source of the rise. See my post here for my view on how the climate works.
In future, do your homework before you uncap your electronic pen.
barry moore says:
June 7, 2010 at 4:05 pm
The alternative is quite simple assume the worst, global warming is an unstoppable natural cycle, so let us mitigate against it.
But that isn’t the worst. The worst is that we are 18,000 years into an interglacial (there’s some sediment in Ireland that says 19,000 years, but 18,000 is the most popular number) that have lasted somewhere between 15,000-20,000 years – at least since the Ismus of Panama closed up. (Would the Panama Canal help?) Since that’s a range, and the 20,000 years upper limit is not a guarantee, we may have a problem.
Of course if the various Dryas stadials have “reset the clock”, then we’re home dry, but if Milanslavik is right, and it’s all due to orbital dancing – then the stadials won’t have. At which point, ground level is going to be approximately a mile about my head in a lesser timeframe than the Bible covers.
*That* is assuming the worst…
Willis Eschenbach says:
June 7, 2010 at 4:48 pm
“So if year zero has an airborne C of X gigatonnes, and an emission of E gigatonnes, then year one has an airborne C of (X + E) * P.”
Willis,
This can’t work. If there were no manmade emissions, your model would have airborne CO2 down to 31 ppm within a century. And down to 2.5 ppm within 200 years.
It assumes CO2 is absorbed by a large sink into which it disappears without any return flux. No wonder you get an odd time constant.
barry moore says:
June 7, 2010 at 3:11 pm
… For those interested in actual science not manipulated cherry picked statistics from dubious proxies try John Nicols paper which is a true scientific evaluation based on the laws of physics of the so called greenhouse gas effect.
Very good paper Barry, thank you pointing that out. Finally found it at:
http://www.middlebury.net/nicol-08.doc
Will take a while to absorb this one completely.
tallbloke says:
June 7, 2010 at 4:05 pm
After being unsuccessful in simply asking Dr. Ravetz to respond to some of the issues raised in the comments to his post, I tried to shame him into answering by pointing out how childish it is to refuse to answer because you think people are being mean.
I was totally unsuccessful in that attempt as well, he continued with his drive-by posting style …
Now perhaps it was rude and crude of me to actually ask for an answer to people’s objections to his work. And perhaps it was foolish of me to try to shame him into answering. In any case, both didn’t work.
But it was not an “ad hominem”. I was not arguing that his ideas were wrong because he was acting childish. I was trying to get him to stop acting childish, which is a very different game.
But OK, tallbloke, since it seems so crucially important to you to establish that I’m truly a bad sneaky wrong kinda guy, could we just take that as read and get back to real issues? Because you harping on this trivia just makes you look petty, and I don’t think that’s who you are. OK, I confess, I’m an idiot and I’m really, really wrong. I haven’t stopped beating my wife, and I was unconscionably mean to poor Dr Ravetz. I repent of my sins, mea culpa, I will say ten “Hail Marx’s” and I vow to go and sin no more.
You happy now? Can we return to the science?
If the increase in CO2 follows temperature increases by 400 to 800 years or so, as seen in past data, then could the increase we see now have been caused by a temperature increase in the period of around 1000 to 1200?
kadaka (KD Knoebel) says:
June 7, 2010 at 3:06 pm
“…..Other interesting things:
This graph shows (by eyeball estimation) the atmospheric CO2 levels dropped as low as around 180 ppm about 12,000 years ago. However other research concerning plants (link) shows that during the Last Glacial Maximum the plants experienced CO2 concentrations as low as 110 ppm. From this, as opposed to the normal line of inquiry, the question arises as to why the ice cores show such a high level of CO2…..”
__________________________________________________________________________
As Willis and many others have pointed out CO2 is not uniform in the atmosphere near the ground because of the sinks and sources.
For example:
Greenhouse Information and measurements:
“Plant photosynthetic activity can reduce the CO2 within the plant canopy to between 200 and 250 ppm… I observed a 50 ppm drop within a tomato plant canopy just a few minutes after direct sunlight at dawn entered a green house (Harper et al 1979) … photosynthesis can be halted when CO2 concentration aproaches 200 ppm… (Morgan 2003) Carbon dioxide is heavier than air and does not easily mix into the greenhouse atmosphere by diffusion… click
I also remember a study with trees in the open where they found the CO2 in the micro-environment around the leaves dropped to 200 ppm during daylight. Unfortunately I can not find the source.
I did find in my notes “200 pm CO2 trees starve” http://biblioteca.universia.net/ficha.do?id=912067
but the link no longer works… Now all the searches turn up papers showing 180 ppm or lower….HMMMmmmm
I just check a couple of studies the 180 -200 ppm CO2 for trees is now based on “models” derived from the ice cores. GRRRrrrr