Dusting for Fingerprints in the Holocene

Guest Post by David Middleton

Fingerprints are admissible evidence in criminal trials because of their uniqueness. The probability of two human beings having identical fingerprints is very low.

Measurements of δ13C depletion have often been cited as anthropogenic “fingerprints,” proving human culpability for the rise in atmospheric CO2 over the last 200 years or so…

Fig 1) The so-called Suess Effect from John Cook's "The Scientific Guide to Global Warming Skepticism"

While δ13C depletion certainly could be evidence of the Suess Effect, it is not a unique solution; therefore, not a “fingerprint.”

Examples of geologically recent δ13C depletion not of anthropogenic origin…

Fig 2) δ13C depletion during Holocene Climatic Optimum in the Thar Desert of Northwest India (Enzel et al., 1999).

Fig 3) δ13C depletion during Preboreal to Boreal in western Poland (Apolinarska, 2009).

Fig 4) δ13C depletion during last interglacial in the Indian Ocean (Banakar, 2005).

δ13C depletions were associated with warming events ~5,000 years ago in India, ~9,100 years ago in Poland and ~150,000 years ago in the Indian Ocean. It appears to me that δ13C depletion has been a fairly common occurrence during periods of “global warming.” It also appears that δ13C increases have occurred during periods of global cooling…

Fig 5) δ13C rise and depletion across the Little Ice Age in the Yucatan compared to recent δ13C depletion in the Coral Sea.

The red curve in Figure 5 is the Flinders Reef δ13C that was cited as “Human Fingerprint #1” in Skeptical Science’s The Scientific Guide to Global Warming Skepticism.  The rate of δ13C depletion is quite similar to that of the lacustrine deposit on the Yucatan.  The Flinders Reef data do not extend back before the Little Ice Age; so there is no way to tell  if the modern depletion is an anomaly, if the δ13C was anomalously elevated during the 18th and 19th centuries and the depletion is simply a return to the norm or if δ13C is cyclical.

Is it possible that Skeptical Science’s “Human Fingerprint #1” is not due to the Suess Effect? Could it be related to the warm-up from the Little Ice Age?

References

Cook, J. et al., 2010. The Scientific Guide to Global Warming Skepticism.  Skeptical Science.

Banakar V., 2005. δ13C Depleted Oceans Before the Termination 2: More Nutrient-Rich Deep-Water Formation or Light-Carbon Transfer? Indian Journal of Marine Sciences. Vol. 34(3). September 2005. pp. 249-258.

Enzel, Y. et al. High-Resolution Holocene Environmental Changes in the Thar Desert, Northwestern India. Science 284, 125 (1999); DOI: 10.1126/science.284.5411.125.

Apolinarska, K. δ18O and δ13C Isotope Investigation of the Late Glacial and Early Holocene Biogenic Carbonates from the Lake Lednica Sediments, Western Poland. Acta Geologica Polonica, Vol. 59 (2009), No. 1, pp. 111–121.

Hodell, D.A., et al., 2005. Climate change on the Yucatan Peninsula during the Little Ice Age. Quaternary Research, Vol. 63, pp. 109-121. doi:10.1016/j.yqres.2004.11.004

Pelejero, C., et al. 2005. Flinders Reef Coral Boron Isotope Data and pH Reconstruction. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2005-069. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA.

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Gail Combs

Oh, this is great information. Thank you David. It is one of the key points that is always brought up when CO2 is discussed.

Philip Finck

So it is elevated in association with the Little Ice Age……. and it is still elevated compared to 0 – 1400 AD. Note the many precipitous drops far greater that what is seen in the 20th century. There is obviously another mechanism controlling c13/C12 ratio.

Philip Finck

Hold it now … I just realized that the scales are different.Flinders reef was 0 around 1700 and is now <-1 in 2000. Yucatan makes an arch between -2.5 and -4.5 with extreme variability between 1500 and 2000. The Flanders Reef series isn't long enough to say anything meaningful when it is compared to the Yucatan record. Variability of 2 full units in the ratio is very common. If the ratio goes negative due to fossil fuel input then why has the Flinders reef dropped from 0 to -1 while in the Yucatan it was in the -5 range for 1400 years ……. must have been a lot of Aztecks (sp?) burning a lot of coal. Mind you the Yucatan area is full of gypsum …wonder what the C ratio is in gypsum, ie does C12 – C13 speciate when gypsum crystallizes in the evaporite forming process or alternatively what was the C13 – C12 ratio when the gypsum formed in ocean water?
Is the ratio a regional thing versus a global proxy?

Philip Finck

Hold it again. The Flinders Reef (Great Barrier Reef) in the SKS post has the ratio from -1.2 to -3.6. That doesn’t agree with the right hand scale where the curve is placed in Figure 5?

Ditto the thanks David…… I had no idea there were so many examples of the ratio change…. minus human influence. More stuff well within natural variability. I’ve always argued that the isotope doesn’t matter. I think we assume we know more than what we really know.
The Yucatan graph is a bit off if anyone is trying to argue the isotope ratio, at least for that place, is indicative of warming or cooling. And, it is problematic. Not only is the vertical divergence off, so is the frequency.
Just from experience, looking at the graph, I’d say a methodology of some sort, or sampling size changed for gathering information prior to about 1200-1400 as opposed to after. It doesn’t invalidate much of anything…. other than going back beyond 1200.
For those that can’t see, what I’m on about, the intersession between the RWP and MWP is missing, but if you look, @ about 1200-1400….. the graph changes its characteristics.
I hate graphs that look like that…..

To worry about the origin of CO2 is to imply that present (or forecast) concentrations are a cause for concern. Elevated CO2 is an issue only for those who insist on misinterpreting temperature-CO2 cause-and-effect, and those who hate food.

michael hart

This is something I’ve been considering spending more time on. But if I start, I may never finish. ‘Cold’ isotope-labels are frequently used as probes and internal standards in Chemistry, but the number of processes that can cause isotope fractionation is more than you can shake a stick at.
Deuterated hydrocarbons can be separated by liquid chromatography. For many enzymes/biological-catalysts I would expect fluctuating isotope effects to be the norm, not the exception. It’s a minefield.

Hoser

It’s pretty annoying there is no actual calendar year 0; we jump to 1 BC, skipping 0.
Get out of the weeds. What is the point of criticizing the Yucatan v Flinders chart? It’s not published peer reviewed work. It’s an interesting comparison just to get people thinking. Isn’t it interesting the curves can be placed on top of each other relatively easily? What the overlay really means, if anything, hasn’t been determined. It serves to help people view the red curve in a larger context. The overlay makes the point the red curve doesn’t necessarily indicate the δ13C decline is due to human influence. Isn’t that the point of the story?

I think the isotope ratio is interesting and worth thinking about. It does possibly reflect human origin, and should be taken seriously as an argument. However . . .
We do not know enough about total CO2 sources and sinks to determine whether the increase in overall CO2 *would not have happened* but for human fossil fuel use. Further we do know that CO2 has risen at a remarkably steady pace in recent decades, despite ups and downs in fossil fuel use. Both of these facts should give us pause.
Finally, many argue that the amount of human emissions is greater than the total increase and, therefore, humans are responsible for the increase (meaning, the biosphere is able to handle part of the human emissions, but not all). However, even if the isotope ratio changes (more CO2-12), consider this analogy:
I run a small business on a cash basis. At the beginning of the year I have $1000, 3 of which are marked with a red dot. Throughout the course of the year I exchange thousands of dollars with many vendors and customers, including occasional transactions with one tiny customer who marks red dots on all his bills. At the end of the year, after thousands of transactions of cash flowing in and out, I count my cash, and it turns out I have $1001, 4 of which are marked with a red dot. According to AGW advocates, the tiny customer who pays only with bills marked with a red dot (i) *must* be the sole source of my $1 profit, and (ii) but for that tiny customer, I would not have made my $1 in profit. It should be easy to see that this is not a valid conclusion. The conclusion is even more shaky if David Middleton’s post is correct, because then we would have to say that there might even be another customer (we’re not quite sure) who sometimes also pays with bills marked with a red dot.

R. Shearer

Finger prints may be on the gun, but the alleged murder victim is happily moving about as if nothing has happened.

Steve R

It seems obvious that the Seuss effect is not just an anthropogenic fingerprint; instead it is the fingerprint of Life. Most plants and virtually all animals consist almost entirely of C12 and are depleted of C13 and C14. Hence when the global biomass increases, the proportion of total atmospheric carbon that is C12 increases, and the proportion that is C14 declines accordingly. The Seuss effect provides conclusive proof that a warm Earth enables life to thrive.

chuck in st paul

I get so worn out reading BS from the Gaia worshippers and rent seekers on the subject of CAGW. This article is just one more reason to be skeptical of the ‘man made’ part. I know we do have some effects such as Urban Heat Island Effect (UHIE) and I am sure our contribution to the Satanic Gases must have some effect, but I am skeptical that it rises above signal to noise ratio of the data itself.

Gail Combs

Since Coal is from dead plants so that is not the origin, I was wonder where the C-13 actually came from and ran into this little gem…

Many thanks to Geophysical Institute, University of Alaska Fairbanks for permission to use the following extract…
… The very rare carbon 14 is another matter, though, because it is radioactive. By losing an electron, every atom of C-14 eventually will decay into an atom of N-14; that is, it will turn into ordinary nitrogen….
1998 by Macquarie University
http://dwb4.unl.edu/Chem/CHEM869Z/CHEM869ZLinks/www.all.mq.edu.au/online/edu/egypt/carbdate.htm

That mess brings to mind this article:

…..“Publishers now employ more people to censor books for content that might offend any organized lobbying group, than they do to check the correctness of facts.” Unchecked errors spread: in 1999 the Boston Globe reported, “Some educators have traced the transmission of errors from one textbook to another and compare the process to the spread of a virus through a population.”
An exasperated William Bennetta explained why so many teachers accept inferior textbooks from these publishers, “[T]he major schoolbook companies… have long recognized that the teacher corps in America includes some desperate dumbbells, and the companies have learned to produce books that the dumbbells will like.” Alistair B. Fraser…, concluded bleakly, “Apparently, most teachers believe everything they teach.” … Cornell professor Donald Hayes, …. reported on results of sampling 788 textbooks used between 1860 and 1992: “Honors high school texts are no more difficult than an eighth grade reader was before World War II.” (And in an essay written over half a century ago Randall Jarrell complained that 1930’s textbooks were much easier than the ones from the 19th century!) So by now our teachers, and their teachers, and their teachers, have been dragged through the same swamp of bad textbooks. They know not what they do, and they know not that they know not….

No wonder CAGW has spread so easily.

Peder Larsen

Gail combs quotes that bit about “every C-14 atom losing an electron” and seems to suggest it’s not correct. She’s right that it makes the naive reader think the atom is losing a shell electron, but of course what is actually going on is nuclear decay, as a neutron becomes a proton by beta decay, emitting an electron and an electron anti-neutrino. Textbooks have a lot of sins for which they should answer, such as watering down the facts to make them” easier.”

SteveSadlov

I am gravely concerned that the concentration of CO2 is below 500ppm. To me, this means we are in a highly vulnerable state. This concentration (or lack of) has been fine during this fairly benign period of Geological History we’ve been in now since the commencement of the Quaternary. We have not had any really major disturbances other than the general dominance of high latitude Continental Glaciation for much of the Q. But no really big extraterrestrial strikes, no widespread volcanic catastrophes, etc. Not if but when the next one of these happens, if we are still below 500ppm I worry that photosynthesis will behave as if the level were far lower (e.g. due to the impacts of the disturbance). From there, a mass die off of photosynthesis based life could occur.

I personally believe that the isotopic signature in the current atmosphere is probobably anthropogenic. But you have hit on one of the most important mysteries in earth science: the PETM isotopic “excursion”. It has been asserted that the PETM was caused by fossil fuel burning as rifting in the north Atlantic separated Greenlandfrom Europe, but the timing really doesn’t work and current rifting through Africa and the Red Sea does not seem to be producing clouds of smoke from the ample petroleum in the region.
I once suggested tounge-in- cheek on Sks that a burst of cosmic rays converted nitrogen to C14, but this would not explain the C13, would it?

Julian Flood

The increase in light isotope C must be caused by fossil fuel burning because we can’t think of any other reason.
Except that warming seas become more stratified and starve the calcareous phytoplankton which usually preferentially fix light C and export it to the deep ocean. So, fewer phytos, less light C pull down, more 12C in the atmosphere.
Oh, yes, we’ve disrupted vegetation cover causing a lot of dust. Dissolved silica runs into the oceans where it feeds diatoms which are the little beasties that get first helpings of nutrients until the silica runs out. Diatoms are not as discriminatory against 13C as the calcareous phytos, so they export proportionately less 12C, signal in atmosphere goes up.
Oh, and of course there’s the fact that oil and surfactant polluted seas warm faster, stratify more, starving the phytos. And waves break less, less CO2 is driven into the ocean which means that phytos are CO2 starved. Some change their metabolism to C4 ( a better way of fixing carbon in times of C famine), C4 phytos outcompete C3 types and, as any fule know, C4 metabolism is less discriminatory against 13C which means proportionately more heavy C is exported to the deep ocean.
And oil polluted seas engage less with the wind,: this reduces currents, pulling up less nutrient-rich water from below. So this starves the phytos which export less light C.
But it must be us burning fossil fuel, because we can’t think of anything else it can be.
Unless the introduction of European earth worms has altered the silica run-off from those areas where they have been introduced to improve agriculture.
Or something else is happening we haven’t noticed yet.
But it must be us.
The graph used on Sceptical Science should be compared with others: far be it from me to suggest that Mr Cook would use sharp practice in his articles, but other depictions show that the ‘anthropogenic’ 12C signal begins in about 1700AD. Which is odd as even the intelligent men in Ironbridge hadn’t yet started destroying Gaia at that date. But it must be us. We can’t think of anything else. [puts fngers in ears] I’m not listening.
JF
PETM: sea erosion breaches a major oil reservoir. Kriegesmarine Effect happens. Big temperature rise. Would such a small event have such a large effect? Well, we are dumping enough light oil down our rivers every fortnight to cover the entire ocean surface and that’s giving us about .2 deg C/decade. During WWII the spilled oil was enough to drive the temperature up by .3 deg C in a few months. I think. All wwe need to do is clean up our act and watch what happens. I bet on cooling.

Bart

There is also the question of diffusion, i.e., how long it takes for the C12 rich gas input to disperse throughout the system. This topic was discussed on a recent thread.
An analogy is as follows. Suppose you have a bucket of water with an incoming flow at the top, and an equal outgoing flow from a hole at the bottom. To the incoming flow, you add about 3% more of blue dyed water. A new equilibrium will be established when the height of the water in the bucket increases 3%. But, before the dye has thoroughly diffused, the water will be bluer at the top than it is at the bottom.
Now, pump in an additional clear water flow near the bottom from an unknown source at a rate which continually increases the level in the bucket over the observation time interval. Where does the blue water now aggregate?

MrD

Can anyone please explain to me why the measured increase in atmospheric CO2 is almost linear; yet the worlds population increase & usage of CO2 generating fuels would more likely be exponential during the 20th C?
Something is not right!

The SUESS effect was first noticed to correct carbon dating before the 1950s when bomb testing first started. C14 is naturally produced by cosmic rays in the upper atmosphere and about 10kg are produced each year this way. After the industrial revolution the concentration of C14 began to get diluted slightly as fossil fuels were burned. This is because fossil fuels essentially contain no C14. The effect was first noticed by Suess who introduced a correction for carbon dating. A recent study from 2002[6] has measured that the effect up until 1950 was to decrease C14 concentrations by 2.4+- 0.35%. By 1950 CO2 levels had risen above pre-industrial values by about 12%. This also provides evidence that just 20% of the increase in CO2 levels by 1950 was due to fossil fuels.
Both these results imply that a maximum of just one quarter of the increase in CO2 concentrations since 1750 are of fossil fuel origin. This means that at least 75% of the observed increase in CO2 is of natural origin. Perhaps a further 15% of this could also be due to human causes – land change, deforestation but it is hard to avoid the conclusion that the majority of it is natural. How can this be ? Have we disrupted the overall carbon cycle such that each year there is a surplus in the recycling of natural CO2 ? Or is this 60% effect due to natural warming which would have occurred anyway ? It seems to me that there could be an error in the estimates that the IPCC use for the lifetime(s) of CO2 in the atmosphere?
The lifetime of a given sample of CO2 molecules is the time needed for 1/e of the CO2 molecules to leave the atmosphere. An unintended experiment was carried out in the 1960s due to nuclear testing which released large amounts of radioactive C14 into the atmosphere. C14 measurements show how this pulse of CO2 decayed with time and derive a lifetime value. The evidence from the delta C13 measurements, and the Seuss effect would support a lifetime of about 7 years. The direct C14 measurements give a value around 10 -14 years. In both cases the fraction of CO2 molecules in the atmosphere for current emission levels reaches a limit of < 10% of today’s atmosphere. It is only by assuming much higher lifetimes of over 100 years that the IPCC predictions are possible.
So the whole AGW model depends on a long lifetime for CO2. The IPCC carbon model (WG1) is described on page 213 of WG1 states :

The CO2 response function used in this report is based on the revised version of the Bern Carbon cycle model used in Chapter 10 of this report (Bern2.5CC; Joos et al. 2001 [1] ) using a background CO2 concentration value of 378 ppm. The decay of a pulse of CO2 with time t is given by:

a0 + sum(i=1,3)(ai.exp(-t/Taui)) , Where a0 = 0.217, a1 = 0.259, a2 = 0.338, a3 = 0.186, Tau1 = 172.9 years, Tau2 = 18.51 years, and Tau3 = 1.186 years.
If you look carefully at this formula you will see that it is made up of 3 independent CO2 lifetimes each with different amplitudes, plus a constant term implying that 22% of anthroprogenic CO2 will remain in the atmosphere for ever!
One objection I have to the form of this model is the concept of using 3 different lifetimes purely from a logical viewpoint, as it kind of assumes that there are 3 different types of CO2 molecule in different queues waiting to leave the atmosphere. I suspect that the model in this form also violates the second law of thermodynamics, since whether there are 3 holes in a bucket of water or just 1 large hole is irrelevant to the rate at which the water leaks out of the bucket !

The SUESS effect was first noticed to correct carbon dating before the 1950s when bomb testing first started. C14 is naturally produced by cosmic rays in the upper atmosphere and about 10kg are produced each year this way. After the industrial revolution the concentration of C14 began to get diluted slightly as fossil fuels were burned. This is because fossil fuels essentially contain no C14. The effect was first noticed by Suess who introduced a correction for carbon dating. A recent study from 2002 has measured that the effect up until 1950 was to decrease C14 concentrations by 2.4+- 0.35%. By 1950 CO2 levels had risen above pre-industrial values by about 12%. This also provides evidence that just 20% of the increase in CO2 levels by 1950 was due to fossil fuels.
Both these results imply that a maximum of just one quarter of the increase in CO2 concentrations since 1750 are of fossil fuel origin. This means that at least 75% of the observed increase in CO2 is of natural origin. Perhaps a further 15% of this could also be due to human causes – land change, deforestation but it is hard to avoid the conclusion that the majority of it is natural. How can this be ? Have we disrupted the overall carbon cycle such that each year there is a surplus in the recycling of natural CO2 ? Or is this 60% effect due to natural warming which would have occurred anyway ? It seems to me that there could be an error in the estimates that the IPCC use for the lifetime(s) of CO2 in the atmosphere?
The lifetime of a given sample of CO2 molecules is the time needed for 1/e of the CO2 molecules to leave the atmosphere. An unintended experiment was carried out in the 1960s due to nuclear testing which released large amounts of radioactive C14 into the atmosphere. C14 measurements show how this pulse of CO2 decayed with time and derive a lifetime value. The evidence from the delta C13 measurements, and the Seuss effect would support a lifetime of about 7 years. The direct C14 measurements give a value around 10 -14 years. In both cases the fraction of CO2 molecules in the atmosphere for current emission levels reaches a limit of < 10% of today’s atmosphere. It is only by assuming much higher lifetimes of over 100 years that the IPCC predictions are possible.
So the whole AGW model depends on a long lifetime for CO2. The IPCC carbon model (WG1) is described on page 213 of WG1 and states :

The CO2 response function used in this report is based on the revised version of the Bern Carbon cycle model used in Chapter 10 of this report (Bern2.5CC; Joos et al. 2001 [1] ) using a background CO2 concentration value of 378 ppm. The decay of a pulse of CO2 with time t is given by:

a0 + sum(i=1,3)(ai.exp(-t/Taui)) , Where a0 = 0.217, a1 = 0.259, a2 = 0.338, a3 = 0.186, Tau1 = 172.9 years, Tau2 = 18.51 years, and Tau3 = 1.186 years.
If you look carefully at this formula you will see that it is made up of 3 independent CO2 lifetimes each with different amplitudes, plus a constant term implying that 22% of anthropogenic CO2 will remain in the atmosphere for ever!
One objection I have to the form of this model is the concept of using 3 different lifetimes purely from a logical viewpoint, as it kind of assumes that there are 3 different types of CO2 molecule in different queues waiting to leave the atmosphere. I suspect that the model in this form also violates the second law of thermodynamics, since whether there are 3 holes in a bucket of water or just 1 large hole is irrelevant to the rate at which the water leaks out of the bucket !

Dixon

I heard about ‘fingerprinting’ CO2 emissions from burning coal based on carbon isotope ratios, down to particular production regions about 10 years ago, but it didn’t strike me as being convincing (I probably didn’t understand the science!). But as I recall anything to do with carbon isotopes always needs a fair pinch of salt, it’s one of those ‘great in theory, but damn hard in practice’ things. Can one of the regular commentators provide an overview primer of carbon isotopes as a post? As a commentator on this thread has already pointed out, living organisms are good at altering isotope ratios. As another pointed out, anthropogenic sources for CO2 might be plausible, but have the other mechanisms been ruled out, or is this just another Climate Science mantra reinforced by repetition rather than hard science?
Has anyone sampled the isotope ratio in carbon being emitted from black smokers?
Interesting comment about spilled oil, I need to think that through…

Julian Flood

Dixon wrote
‘spilled oil. I need to think that through.’
Search for the Ceres picture of the world, zoom in on the Mississippi overflow into the Gulf.
Find the earlier pictures of the Gulf oil spill and see the way the air above the slick is eating stratocumulus clouds at the edges.
Thinking is good! Wigley should have done it, then he would not have needed to ask ‘why the blip’.
JF

FerdiEgb

[You seem to be quick to think that your contributions are not being dealt with quickly enough . . they fall into the spam bin along with hundreds of other spam postings and it takes time to sift through the pile to release valid responses. . . reposting is pointless as are attempts to spur moderators to attend to your concerns . . everything is dealt with seriatim, you will be heard . . kbmod]
Well, it seems that this is one of the discussions which will return to WUWT every (few) month(s)…
One need to make a differentiation between direct measurements of the C13/C12 ratio and different proxies which have some relation with that ratio, but where confounding factors may be at work. That is especially the case for organic materials, influenced by a host of factors, like available light, nutritients even the CO2 concentration itself and also for inorganics made by organisms in shallow waters where pH, local concentration and depletion may play a role in de d13C ratio.
Ice cores give direct measurements of the C13/C12 ratio of CO2 in trapped air. These were measured by cold crushing the ice, cryogenic freezing, distillation of CO2 and measuring with a mass spectrometer.
The d13C level in the atmosphere over the Holocene can be followed in the Taylor Dome ice core:
http://medias.obs-mip.fr/paleo/taylor/indermuehle99nat.pdf
The average variability is +/- 0.15 per mil over the Holocene, up to 1,000 years ago.
The next ice cores one can use are the Law Dome ice cores. The combination of ice cores, firn and direct measurements allows us to reconstruct the full Holocene d13C changes up to today with increasing better resolution:
http://www.mendeley.com/research/stable-isotope-constraints-on-holocene-carbon-cycle-changes-from-an-antarctic-ice-core-1/
This can be compared to a proxy that is living in shallow and deeper waters (down to 200 m) where coastal influences are minimal: coralline sponges. The calcite deposit is isotopic identical to the surrounding seawater, which in the Carribean is rather fast refreshed and largely similar over the whole North Atlantic Gyre. The resolution of the calcite d13C ratio is 2-4 years over the past 600 years:
http://www.agu.org/pubs/crossref/2002/2001GC000264.shtml the full article is pay walled, but the most important graph, combining ice cores, firn and air d13C measurements with ocean surface measurements is here:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/sponges.gif
This shows some small pre-industrial variability of +/- 0.15 per mil d13C. Since about 1850, there is a faster and faster continuous drop of d13C of nowadays already -1.6 per mil d13C. There is no knowledge of non-human reasons like burning down about 1/3rd of all land vegetation or a similar natural disaster involving gas, oil or coal burning, And human releases fit the equation more than necessary to explain the downward trend…
Thus all together, the ice cores show conclusively the influence of human activities on the d13C ratio of the atmosphere. Proxies in the oceans need to be used with caution, as the influence of temperature on the d13C ratio must be separated from the influence of the addition of fossil fuel burning. As the first influence on coralline sponges is rather limited (+/- 0.15 per mil d13C over 350 years) and there is a direct correlation (with lag) between the measured d13C change in the atmosphere and in the sponges for recent years, the sponges show that humans are responsible for the d13C changes in the ocean’s surface layer.

FerdiEgb

clivebest says:
March 29, 2012 at 2:00 am
A recent study from 2002 has measured that the effect up until 1950 was to decrease C14 concentrations by 2.4+- 0.35%. By 1950 CO2 levels had risen above pre-industrial values by about 12%. This also provides evidence that just 20% of the increase in CO2 levels by 1950 was due to fossil fuels.
The common problem with this is that one need to make a distinction between the origin of the CO2 molecules which are in the atmosphere and the origin of the increase in total amount of CO2 in the atmosphere. Look at the example that Bart showed: we add a some blue colored water to a bucket where clear water is added to the top and leakes away at the bottom and is recirculated via a huge tank with near unlimited capacity. The water in the bucket wil be colored somewhat by the blue addition (which shows the origin), how much, that entirely depends of the ratio between colored and clear water addition. But the addition of blue water also increases the height of the waterlevel in the bucket. That is INdependent of the original flow in- and out. The original height of course depends of the initial flow, but the increase in height only depends of the additional flow.
So what is important in this case? What rests in the atmosphere of original human emissions (the blue coloured ones…) is not important at all, only the total increase (the increase in height) is important. The bomb 14C decline ratio only shows how fast the atmosphere is exchanging CO2 with other reservoirs (about 20% per year or a residence time of ~5 years), but that doesn’t say anything about how fast an excess amount of CO2 in total is removed (that is 4 GtC/year of the total 800 GtC in the atmosphere, or a 1/e decay time of ~55 years). Two completely different time constants without any relationship. Here a graph which shows (based on realistic figures) the difference between what happens with the total amount of CO2 in the atmosphere if humans should add 200 GtC from fossil fuel at once to the pre-industrial atmosphere and what happens to the human “fingerprint”:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/fract_level_pulse.jpg where FA is the fraction of “human” CO2 in air, FL the fraction in the ocean surface (not important here), tCA total carbon in air and nCA natural carbon in air.
The human fingerprint is gone after some 50 years, but the effect of the one-time addition on the total amount still is measurable after 160 years…
While I don’t agree with the Bern model, what they do is comparing the decay time between the atmosphere and different compartiments: the fastest is for the ocean’s surface, but that has a limited capacity (~10% of the increase), the medium term for the deep oceans and vegetation and the lowest for long-term processes like rock weathering, carbonate sedimentation,… My objection is that there is currently no limit in sight for the deep ocean and vegetation uptake, thus the slowest and residual terms are highly questionable.

FerdiEgb

climatereflections says:
March 28, 2012 at 5:16 pm
I run a small business on a cash basis.
Good analogy, except that in this case you know from the “red dot” customer that he added 2 dollars per year to your bussiness. A simple calculation learns you dat without that customer, you would have had a net loss of 1 dollar per year. The number of red dot bills still left in your cash register is not important, the in-out of total bills and specific red dot bills is what is important.
The same for the CO2 levels: we add about 8 GtC/year (based on fuel inventories -taxes- and fuel burning efficiencies) and we measure an increase of about 4 GtC/year. Thus nature as a whole is a net sink for atmospheric CO2, regardless of how much is exchanged with other compartiments during that year.

Carbon dating is over-rated and based on simplistic assumptions. First that all atmosheric C-14 is from N-14 decay and that this decay rate is constant based on non-constant solar/cosmic rays. The non-constant production rate becomes a greater problem over time, causing an increased proxy error. Carbon dating is based on the assumption that C-13/14 ratios are set by metabolism with atmospheric Carbon and then begin a fixed decay rate upon the death of the organism. Biologists in the sixties divided life into “Bacteria” and “Eukaruota”, only to further divide the single celled life forms into “Bacteria” and “Archaea” a decade later. This was based on RNA and metabolism differences of lifeforms in the worlds most extreme environments. Living in the intestional tracts of termites and cattle, thriving at high-temperature, high-pressure thermal vents, these “new” life-forms are abundant in the Antarctic and feed on “elemental” CO2 and CH4 flowing from under-sea vents. These “natural” Carbon sources have reduced C-14 and therefore, the marine animals that are fed further up the food chain have reduced C-14 ratios as well. Fresh killed seals and penquins have a “Carbon dated age” of over 3,000 years old. The “elemental” production of Carbon is NOT constant, and is UNKNOWN, introducing further errors.
See “Amazing ! New ! Wrongco’s Proxy Crock !” for more of the ridiculous proxy madness.

FerdiEgb

MrD says:
March 28, 2012 at 11:50 pm
Can anyone please explain to me why the measured increase in atmospheric CO2 is almost linear; yet the worlds population increase & usage of CO2 generating fuels would more likely be exponential during the 20th C?
The increase of CO2 in the atmosphere is slightly exponential, hardly visible as it is a fraction of the accumulated human emissions, which increase rather linearly over time. Here an oversight:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_emiss_increase.jpg

FerdiEgb

Julian Flood says:
March 28, 2012 at 10:30 pm
It is simple to show that the ocean temperature increase is not the cause of the CO2 increase or d13C decline: the temperature influence on CO2 pressure in seawater is too small (16 microatm/degr.C) and seawater CO2 has a too high d13C level (0-1 per mil for deep ocean waters, 1-4 per mil for ocean surface waters, the atmosphere is at -8 per mil). Thus any substantial release of CO2 from the oceans would increase the d13C level of the atmosphere while we observe a fast decline.
It is impossible to make a differentiation between the use of fossil fuels and of burning/decayling vegetation. But there is an alternative: we know with reasonable accuracy how much oxygen our fossil fuel burning uses. We know with some accuracy since 1990 how much oxygen is removed from the atmosphere. The difference is what the total biosphere is using or producing. It shows that the total biosphere (land and sea plants, animals and insects) is producing more oxygen that it uses. Thus the total biosphere is a net source of oxygen, thus a net sink for CO2 and preferably 12CO2. Thus leaving relatively more 13CO2 in the atmosphere and not the cause of the decline in d13C.
As oceans and biosphere are the only main huge sources and sinks, there is little doubt left that humans are entirely responsible for the d13C decline (and the CO2 increase). Other sources are too high in d13C (volcanoes, carbonate rock weathering) and too small in emissions. The difference in methabolism between C4 and C3 plants plays no role here, as both have d13C levels below atmospheric, thus both increase the d13C level when there is more growth than decay. And the earth is greening…

FerdiEgb

Mods, some large comment of mine disappeared in cyberspace… Thanks!

Werner Brozek

MrD says:
March 28, 2012 at 11:50 pm
Something is not right!

Exactly how linear and how exponential are we talking about? See the graph below. Would you happen to have a graph that shows the use of fuels is more exponential?
http://www.woodfortrees.org/plot/esrl-co2/from:1958/plot/esrl-co2/from:1958/trend

BioBob

FerdiEgb says: “It is simple to show…”
PLEASE. You make me cringe when I see such statements. You make it sound like humans have precise, extensive and comprehensive data and knowledge about biotic and geochemical process when, in fact, we have very little.
Can you give me accurate numbers for “delta” biotic, soils, & bedrock carbon mobilization resulting from the acidification of precipitation for the past 50 to 100 years over extensive portions of continents ? No.
Can you tell me the decadal variability of carbon mobilization from crustal movement, subduction, etc. No.
Can you tell me anything with known quantitative accuracy about the historical and / or spatial variability of geochemical processes ? No.
Can you tell me anything with known quantitative accuracy about the historical and / or spatial variability of biotic-chemical processes ? No
Restrain yourself to reality, please. We know just enough to begin interesting research which will decrease our ignorance about the issue.

FerdiEgb says: “A simple calculation learns you dat without that customer, you would have had a net loss of 1 dollar per year.”
No. It is true that at some level we could argue that I wouldn’t have gained the extra dollar if I didn’t have that customer. But you are ignoring all the other customers who paid in much greater sums. It doesn’t make any sense to say that the guy who paid me an extra $100 wasn’t responsible for the increase, while the guy who paid me an extra $1 is responsible for the whole increase. Especially if there would have been an offsetting purchase from another customer if my $1 customer didn’t his $1 worth of my goods.
*Even if* humans were the only possible source of CO2-12, which is very doubtful, to conclude that humans are causing the general increase in CO2 requires two massive unproven assumptions: (i) we know what all the other sources and sinks are and what their amounts are, and (ii) we know how all the sources and sinks interact with each other with enough precision to be able to calculate how they interact with humans’ minor contribution.

FerdiEgb says: While I don’t agree with the Bern model, what they do is comparing the decay time between the atmosphere and different compartiments: the fastest is for the ocean’s surface, but that has a limited capacity (~10% of the increase), the medium term for the deep oceans and vegetation and the lowest for long-term processes like rock weathering, carbonate sedimentation,… My objection is that there is currently no limit in sight for the deep ocean and vegetation uptake, thus the slowest and residual terms are highly questionable.

I understand and agree with your point about the incremental increase to atmospheric CO2. However the problem I have with the BERN model is their constant – a0 term. This says that the response to a pulse of 1 unit of CO2 added to the atmosphere are 3 independent exponential decays PLUS a constant term a0 = 0.21. This would imply that 20% of man made CO2 will remain forever in the atmosphere! This cannot be correct since we know that 50 million years ago CO2 levels were several times greater than today.
So let’s instead take a simple model with a single (average) lifetime – Tau. We represent all human CO2 emissions as being one annual pulse per year added to an unperturbed atmosphere before the industrial revolution balanced at 750 Gtons of CO2. Then once a year a pulse of N0 = 5.5 Gtons of CO2 is added to the atmosphere due to human fossil fuel emissions. Each pulse then decays away with a lifetime Tau. Emissions at this level by man are assumed to continue forever. Then the accumulation of total CO2 in the atmosphere for year n is simply given by.
CO2( n) = N0( 1 +sum(i=1,n-1) (exp(-n/Tau)))
If we assume that n is very large then we can treat this sum as an infinite series and the atmosphere will eventually saturate at a certain percentage of anthropogenic CO2 concentration.
Multiplying both sides by exp(1/Tau) we can derive that the sum in the limit as n-> infinity is
CO2(n) = N0/(1-1/exp(1/Tau))
Taking some possible values for Tau we can calculate converged CO2 levels:
Tau Fossil Limit (Gtons) Fraction of 750 Gtons
5 30.3 4.0%
7 41.3 5.5%
10 57.8 7.75%
14 74.3 10%
50 272.3 36%
100 547.2 73%
200 1103 147%
In other words if mankind simply continued burning fossil fuels for ever at current rates – then the atmosphere would eventually stabilize at about double pre-industrial CO2 levels. So this on its own would lead to a ~ 1 degree rise in temperatures, ignoring climate feedbacks.

Bart

clivebest says:
March 29, 2012 at 1:57 am
“If you look carefully at this formula you will see that it is made up of 3 independent CO2 lifetimes each with different amplitudes, plus a constant term implying that 22% of anthropogenic CO2 will remain in the atmosphere for ever!”
The idea here is to model a “fat tail” response with a sum of exponentials. Presumably, the constant term models an exponential which has a time constant much longer than any interval of interest.
I’m not saying it is an accurate equation, just helping understand the theoretical basis.
FerdiEgb says:
March 29, 2012 at 7:27 am
“Ice cores give direct measurements of the C13/C12 ratio of CO2 in trapped air. These were measured by cold crushing the ice, cryogenic freezing, distillation of CO2 and measuring with a mass spectrometer.”
And, there is no reference, no “control” experiment possible to verify that the measurements of ancient CO2 are valid. We do not really know how the trapped gases diffuse through the ice over eons of time. We have only a model.
FerdiEgb says:
March 29, 2012 at 8:10 am
“…we add a some blue colored water to a bucket where clear water is added to the top and leaks away at the bottom and is recirculated via a huge tank with near unlimited capacity.”
It isn’t all recirculated. A goodly part is sequestered more or less permanently. The relevant question is, how fast is the rate of semi-permanent sequestration? I have seen no evidence which convinces me that anyone has a good handle on that rate.

FerdiEgb

clivebest says:
March 29, 2012 at 11:04 am
The a0 term is explained by the IPCC as extremely slow geological processes which remove CO2 from the atmosphere. That may be important if all other processes are exhausted, but the problem is in the a2 term: they limit the capacity of the deep oceans (and vegetation) to 34% of the emissions, while there is no reason for that. The deep oceans are far from saturated in CO2, thus can dissolve a lot more CO2. As the deep ocean carbon content is ~37,000 GtC all the CO2 emitted by humans since the start of the industrial revolution (~370 GtC) indiuced an increase of some 1% in the deep oceans, if that was the only sink. After some 800 years of mixing, that would return to the atmosphere and ultimately increase the atmospheric CO2 content with 1%, more or less permanently, awaiting the action of the slower removal processes. Only if we burned all available oil and a lot of gas and coal (3,000-5,000 GtC), that would significantly increase the atmosphereic CO2 content with a substantial amount over a long period of time.
Your calculation is right if you have a constant addition of CO2 by humans, but the human emissions are quite linearly increasing, leading to a slightly exponential increase in the atmosphere with an incredible lineair ratio to the accumulated emissions:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
As long as the year by year emissions increase, I don’t think that there will be a limit to atmospheric CO2 levels…

FerdiEgb

climatereflections says:
March 29, 2012 at 10:58 am
(i) we know what all the other sources and sinks are and what their amounts are, and (ii) we know how all the sources and sinks interact with each other with enough precision to be able to calculate how they interact with humans’ minor contribution.
We only know to a certain extent what the individual sinks and sources are and their variability. And we have little idea what the interactions are. But that is not important at all: we know quite exactly the result at the end of the year. Not only in gain or loss, but also the variability in gain or loss over the past 50+ years. Even if all or some of the input flows doubled or halved, that is near fully compensated by a similar increase or decrease of the output flows. See:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em.jpg
The average increase in the atmosphere is around 50% of the emissions, the variability of the increase is also about 50% around the trend. That is mainly a result in sink capacity changes due to temperature variability. But in all years nature as a whole was a net absorber of CO2, not a source. In this case, human emissions are the single non-natural source of CO2 (and hardly a sink). Thus one must compare the non-natural source to the combination of natural sources and sinks, no matter what the individual natural sources and sinks did or how they changed.
Even if you don’t do any bookkeeping at all during the day, and only know that you have added some 2 dollars of your own money at the beginning of the day to your cash register, you know that your bussiness is not going well if you find only 1 dollar extra in cash at the end of the day… And if that remains so for 50+ consecutive days, better look for another job…

George E. Smith

“”””” Gail Combs says:
March 28, 2012 at 7:40 pm
Since Coal is from dead plants so that is not the origin, I was wonder where the C-13 actually came from and ran into this little gem…
Many thanks to Geophysical Institute, University of Alaska Fairbanks for permission to use the following extract…
… The very rare carbon 14 is another matter, though, because it is radioactive. By losing an electron, every atom of C-14 eventually will decay into an atom of N-14; that is, it will turn into ordinary nitrogen….
1998 by Macquarie University
http://dwb4.unl.edu/Chem/CHEM869Z/CHEM869ZLinks/www.all.mq.edu.au/online/edu/egypt/carbdate.htm
That mess brings to mind this article:
…..“Publishers now employ more people to censor books for content that might offend any organized lobbying group, than they do to check the correctness of facts.” Unchecked errors spread: in 1999 the Boston Globe reported, “Some educators have traced the transmission of errors from one textbook to another and compare the process to the spread of a virus through a population.” “””””
Well Gail, how right you are; and the BGs 1999 report.
I just got back from two weeks in New Zealand; during which I visited the University of Auckland Physics Department, where I had meetings with three different Profs, including Prof Roger Davies, who authored the recent “Sky is falling” (clouds anyway!). So we had a good chat on that, and I got an unexpurgated copy of the paper.
Friend Myrrh will be horrified to learn that Prof Davies told me bluntly, that “there is no such thing as “heat” “. He might very well have added “or “light” either. Both are simply human psycho-physical responses to different parts of the electro-magnetic radiation energy spectrum. He jumped at my suggestion that “heat” is a verb; not a noun; he even liked that. He’s a Prof in the Environental Science section of the Physics Departmentwhich is not part of the Political Science department.
Prof Davies introduced me to Assoc. Prof Phil Yock, who is a particle Physicist and Astro-Physics also. Prof Yock was the Mentor of Dr Charles Alcock, who is now the Director of the Harvard Smithsonian Institute for Astrophysics, and presumably the boss of Dr Willie Wei Hock soon, and formerly Dr Sally Baliunas; who is now retired. I was there at the dinner, where Dr Alcock received a Distinguished Alumni Award from the Alum assn; they jokingly refer to them as the Iniversity Knighthoods.
So I was introduced to Dr Alcock, and mentioned Willie and Sallie to him, and he smiled when I mentioned Willie Soon, and said, he doesn’t always agree with Willie.
But back to Assoc. Prof Phil Yock, who called up my old Electronics instructor Prof Brian Earnshaw, now retired, and we had a beer and lunch together (with Yock).
So I happened to mention that every elementary text on electricity or electronics, contains a completely incorrect statement of “Ohm’s Law”.
Yock agreed, and then said; “we still teach it that way.”
So what they teach as “Ohm’s Law” says :- E = I x R, or I = E / R, or R = E / I ,your choice.
So then who made this discovery, and stated THIS law ?
“For a certain class of materials; namely metallic conductors, when all other physical conditions are held constant, the current flowing in the circuit, is linearly proportional to the applied Voltage.”
In other words; the ratio of the applied Voltage to the current flowing is a constant.
So r (ratio) = E / I = R = constant.
Well it actually WAS George Simon Ohm who made that discovery; so “Ohm’s Law” actually is:-
R = Constant. E = I x R is merely the definition of R (resistance).
And for most conductive materials, Ohm’s Law is NOT obeyed. Some folks say that incandescent lamps don’t obey Ohm’s Law; but they forget that little clause; “when all other physical conditions are held constant” ; and that includes the Temperature, which is nowhere near constant with an incandescent lamp, which actually DOES obey Ohm’s Law.
Prof Yock was not apologetic, that they still teach students that E = I x R is Ohm’s law.
How about I = Io.exp(qV/kT-1) which is the current relationship for LEDs (and other semiconductor diodes).
So failure to teach the original research results of science; but revamping it in other words, often leads to quite eroneous conclusions, and teachings.
Prof Davies introduced me to

FerdiEgb

Bart says:
March 29, 2012 at 11:37 am
And, there is no reference, no “control” experiment possible to verify that the measurements of ancient CO2 are valid. We do not really know how the trapped gases diffuse through the ice over eons of time. We have only a model.
The gas diffusion through ice was (theoretically) calculated, based on the “warm” (-20 degr.C) Siple Dome ice core which shows some remelt layers. That gives a theoretical broadening of the resolution for middle depths from 20 to 22 years and for the near bottom part from 20 to 40 years. But even so, that doesn’t change the average levels over that broader period of time, only that faster variations than the resolution wouldn’t be observed.
Even if that gives some fractionation of the isotope ratios, that would be seen in high fluctuations from sample to sample (if the sampling was over a too short time span). But the resolution gets better with increased accumulation rates, including a 20 years overlap with direct measurements at the South Pole for the period 1960-1980.
For the colder (-40 degr.C) ice cores in central Antarctica, there is no sign at all for any migration over 800,000 years. If that was the case, the rather constant ratio between CO2 levels and temperature (proxy) would fade over time with each 100,000 years period back in time.

FerdiEgb

BioBob says:
March 29, 2012 at 10:48 am
I totally agree that we do know very little about a lot of processes which influence the carbon cycle on seasonal to geological scales. But there are fundamental points which can be explained in a quite simple way.
We know that all oceans at all depths (except at the inflow of rivers) have a d13C level of ~0 to +5 per mil. We know that the atmosphere had an average of -6.4 to nowadays -8 per mil d13C. So whatever the exchanges were, it is quite certain (even including the fractionation at the sea-air border) that the oceans are NOT the source of the d13C decline in the atmosphere and thus NOT the cause of the CO2 increase. That is the only important point.
There may be other increased natural sources with low d13C (seeping methane, burning coal seems,…), but as nature as a whole is a net sink for CO2 over the past 50+ years, that means that either other natural sources decreased at a similar rate or some sinks increased at a similar rate. Thus however natural sources and sinks individually behaved over the past 50 years, the sum of all them together was a net sink, all 50+ years.
On the other hand, we know that if all human emissions remained in the atmosphere, the increase would have doubled and the d13C decline would have tripled, compared to what is measured. Thus not only is nature a net sink for CO2, but there is a natural exchange with higher d13C level CO2 (probably from the deep oceans) which replaced about 2/3rd of the human induced CO2 over time.
The change in d13C ratio and oxygen use (and other human induced gases like CFC’s) can be used to track several CO2 flows into where they are going and at what rate (including diffusion rates in firn for ice cores and distribution of flows in the -deep- oceans). See e.g.:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
So, indeed we know little, still have much to learn, but we do know several important things.

Reply: FerdiEgb

As long as the year by year emissions increase, I don’t think that there will be a limit to atmospheric CO2 levels…

It is clear that emissions cannot increase forever. We have about 50-100 years of economic Oil and Coal left . Optimistically there are probably also another 50 years of natural gas. Therefore emissions are bound to stabilise and atmospheric CO2 will level off by the end of this century and then slowly decline. This will happen independently of green eco-politics and anti-growth hype. We have a choice whether to use the next 50 – 100 years to develop radical new energy sources or follow the eco-route back to low density living. Should we give up growth and return to a quasi-neolithic “green” society based on sustainable energy ( wind, wood burning, and the sun) which could at most support 1/10th of the current world population, or should we invest in nuclear fusion ? All renewable energy is way too low density( 2-3 watts/m2 ) to support urban life – so It is either nuclear or neolithic. Take your choice.

FactChecker

Does anyone know what happened to Murry Salby? Did he disappear down a black hole? I haven’t heard mention of that guy for a long time now… anyone knows what happened to him?
http://wattsupwiththat.com/2011/08/05/the-emily-litella-moment-for-climate-science-and-co2/

Bart

FerdiEgb says:
March 29, 2012 at 12:19 pm
“The gas diffusion through ice was (theoretically) calculated, based on…”
Repeating what I stated, albeit with flourishes and handstands, does not change what I said.
“But that is not important at all: we know quite exactly the result at the end of the year.”
Still flogging that dead horse, I see. I honestly had a little glimmer of hope we had gotten through to you last time.

FerdiEgb

Bart says:
March 29, 2012 at 1:26 pm
Repeating what I stated, albeit with flourishes and handstands, does not change what I said.
See http://ns.geocraft.com/WVFossils/Reference_Docs/CO2_diffusion_in_polar_ice_2008.pdf
The estimate of migration speed in the Siple Dome is based on direct measurements, not on a model. Still theoretical, as migration near remelt layers is not necessary the same as through “normal” ice layers. Anyway migration speed is very low and doesn’t change the averages in levels or d13C ratio. Only changes the resolution.

Bart

FerdiEgb says:
March 29, 2012 at 2:57 pm
“The estimate of migration speed in the Siple Dome is based on direct measurements, not on a model.”
Not a chance. Nobody was around in the deep past to sample the air, record it, and have it available to compare to the derived measurement today.
Nothing is completely reliable until it has been tested in the lab, and the theory compared to observation in a closed loop fashion. That is why all new commercial products are tested thoroughly before they go to market, and sample tested thereafter to ensure maintenance of performance. You never know for sure what will come out when the theory is tested against reality. A precise match between prediction and observation on the first test run is, by far, the exception rather than the rule.

FerdiEgb: “we add about 8 GtC/year (based on fuel inventories -taxes- and fuel burning efficiencies) and we measure an increase of about 4 GtC/year. Thus nature as a whole is a net sink for atmospheric CO2, regardless of how much is exchanged with other compartiments during that year.”
Setting aside for a moment the question of whether human emissions can be said to have caused the increase, which is an interesting question, it occurs to me that there is another interesting issue here. If we go off of these numbers, it looks like natural sinks are increasing their rate of uptake by about 4GtC/year. This suggests that natural sinks have an ability to uptake much more today than they were uptaking, say, 50 years ago. After a decade, for example, natural sinks would be uptaking about 40GtC/year more than they were a decade previously. This seems to be in contradiction to the statements we sometimes hear that there is a particular amount of “normal” natural uptake (apparently not true) or that there is a careful balance beyond which the natural sinks cannot uptake any more (possibly true, but unknown).
Is this additional uptake over the last several decades reflected primarily in vegetation? Other sinks? Is it temporary?
Do the numbers for increases in CO2 overall match up with this increased uptake ability in nature and increased human emissions?

Bart

FWIW to anyone reading this thread: The fundamental reason I doubt that the recently recorded rise in CO2 is most significantly of human origin is the simple fact that accidents do not happen in Nature. If the feedback loop governing CO2 concentration is so weak as effectively to allow 100% accumulation of the anthropogenically released CO2 in the oceans and atmosphere, then it is too weak to have established an equilibrium and maintained it tightly for thousands of years before the Industrial Age.
Ferdinand has constructed a narrative which, superficially, appears plausible. But, it is based on unfounded confidence in measurements which have large error bars, models for the carbon cycle which have not been completely validated and are very likely substantially incomplete, and neglect of the fundamental dynamism of the system.
A similar narrative was constructed for Anthropogenic Global Warming and, so long as the Global Average Temperature Metric (GATM) appeared to be rising in the latter third of the 20th century, researchers had high confidence that the hypothesis was correct. But, then they hit a brick wall when the GATM stalled after 1998. The evidence that a global cooling cycle has now commenced, which will endure for the next 20-30 years, is compelling. And, it is now apparent that inconvenient facts which were neglected or ignored in constructing the AGW narrative should never have been ignored, e.g., in particular, the rising GATM of the early third of the 20th century which, with hindsight, we can now see is nearly identical to the rise in the latter third.
You cannot just neglect fundamental discrepancies with the knowledge base, and a plausible narrative, especially one which takes short cuts in neglecting inconvenient data or knowledge, is NOT proof. Until the discrepancies are resolved, the hypothesis remains just that.

FerdiEgb

climatereflections says:
March 29, 2012 at 4:04 pm
If we go off of these numbers, it looks like natural sinks are increasing their rate of uptake by about 4GtC/year. This suggests that natural sinks have an ability to uptake much more today than they were uptaking, say, 50 years ago. After a decade, for example, natural sinks would be uptaking about 40GtC/year more than they were a decade previously.
The uptake by nature seems rather linear with the increase in the atmosphere. From the long term past (ice cores) there is a quite nice relationship between CO2 en temperature (CO2 following temperature with a lag) of about 8 ppmv/°C. Based on that relationship, the CO2 level at the current temperature should be around 290 ppmv. In reality the CO2 levels are near 400 ppmv. That gives more pressure for CO2 to sink into the cold polar waters towards the deep oceans (and less pressure difference at the equator at the upwelling places) and more pressure to dissolve in alveoles water of plant leaves, all other confounding variables being equal. Compared to the steady state level of 290 ppmv, the extra sink rate is near linear in ratio with the pressure difference. All together, it looks like that nature as a whole is behaving as a simple first order process coping with a disturbance.
The emissions and increase in the atmosphere are directly coupled:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
not directly because of the emissions, but because the emissions lead to increased atmospheric CO2 pressure which leads to increased uptake. On a year by year base that gives:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em.jpg
where the variability around the trend is mainly caused by temperature variability (explaining ~60% of the variability). The 1992 Pinatubo eruption and the 1998 El Niño have a measurable impact. Using that impact, the short term influence of temperature on the rate of change is ~4 ppmv/°C.
Besides the natural variability, which doesn’t seem to increase or decrease over time, it looks like that the increase in uptake and the increase in the atmosphere are in a near constant ratio with the emissions, probably because the emissions continue to increase over time. I need to make an update for the past years, as there may be some impact from the economic crisis.
The uptake capacity of the deep oceans is enormous, as they are far from saturated for CO2. The same for vegetation, which have theoretically an unlimited storage capacity. The limiting factor is diffusion speed in the oceans and diffusion + reaction speed in plants. While the atmospheric CO2 pressure difference with the steady state doubles, the uptake speed in average increases with 50-55%.
Based on oxygen and d13C measurements, one can estimate where the extra CO2 is sequestered:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf

FerdiEgb

Bart says:
March 29, 2012 at 4:25 pm
If the feedback loop governing CO2 concentration is so weak as effectively to allow 100% accumulation of the anthropogenically released CO2 in the oceans and atmosphere, then it is too weak to have established an equilibrium and maintained it tightly for thousands of years before the Industrial Age.
The deep oceans and vegetation have sufficient capacity to allow sequestering of 100% of the emissions. As already explained to climatereflections, the limiting factor is the diffusion speed, which is directly proportional to the pressure difference between pCO2(atm) and pCO2(aq), all other confounding variables (water temperature, wind speed, sink and upwelling flows) being equal. The time factor is important here: historical CO2 had multi decades to millennia to maintain equilibria around the temperature dictated setpoint. The current injection of human emissions is higher than what the decay rate (~55 years e-fold factor) can cope with on short time intervals.

Bart

FerdiEgb says:
March 30, 2012 at 2:01 am
“The time factor is important here: historical CO2 had multi decades to millennia to maintain equilibria around the temperature dictated setpoint.”
It is important. As already explained, it is inconsistent with a tightly regulated atmospheric CO2 concentration.
“The current injection of human emissions is higher than what the decay rate (~55 years e-fold factor) can cope with on short time intervals.”
You think. We shall see.