For a another view on the CO2 issue, please see also the guest post by Tom Vonk: CO2 heats the atmosphere…a counter view -Anthony
Guest Post by Ferdinand Engelbeen
There have been hundreds of reactions to the previous post by Willis Eschenbach as he is convinced that humans are the cause of the past 150 years increase of CO2 in the atmosphere. For the (C)AGW theory, that is one of the cornerstones. If that fails, the whole theory fails.
This may be the main reason that many skeptics don’t like the idea that humans are the cause of the increase and try to demolish the connection between human emissions and the measured increase in the atmosphere with all means, some more scientific than others.
After several years of discussion on different discussion lists, skeptic and warmist alike, I have made a comprehensive web page where all arguments are put together: indeed near the full increase of CO2 in the atmosphere is caused by the human emissions. Only a small part might have been added by the (ocean) warming since the LIA. That doesn’t mean that the increase has a tremendous effect on the warming of the earth’s surface, as that is a completely different discussion. But of course, if the CO2 increase was mainly/completely natural, the discussion of the “A” in AGW wouldn’t be necessary. But it isn’t natural, as the mass balance proves beyond doubt and all other observations agree with. And all alternative explanations fail one or more observations. In the next parts I will touch other items like the process characteristics, the 13C and 14C/12C ratio, etc. Finally, I will touch some misconceptions about decay time of extra CO2, ice cores, historical CO2 measurements and stomata data.
The mass balance:
As the laws of conservation of mass rules: no carbon can be destroyed or generated. As there are no processes in the atmosphere which convert CO2 to something else, the law also holds for CO2, as long as it stays in the atmosphere. This means that the mass balance should be obeyed for all situations. In this case, the increase/decrease of the CO2 level in the atmosphere after a year (which only shows the end result of all exchanges, including the seasonal exchanges) must be:
dCO2(atm) = CO2(in1 + in2 + in3 +…) + CO2(em) – CO2(out1 + out2 + out3 +…)
The difference in the atmosphere after a year is the sum of all inflows, no matter how large they are, or how they changed over the years, plus the human emissions, minus the sum of all outflows, no matter how large they are, wherever they take place. Some rough indication of the flows involved is here in Figure 1 from NASA:
From all those flows very few are known to any accuracy. What is known with reasonable accuracy are the emissions, which are based on inventories of fossil fuel use by the finance departments (taxes!) of different countries and the very accurate measurements of the increase of CO2 in the atmosphere on a lot of places on earth, including Mauna Loa.
Thus in the above CO2 mass balance, we can replace some of the items with the real amounts (CO2 amounts expressed in gigaton carbon):
4 GtC = CO2(in1 + in2 + in3 +…) + 8 GtC – CO2(out1 + out2 + out3 +…)
Or rearranged:
CO2(in1 + in2 + in3 +…) – CO2(out1 + out2 + out3 +…) = – 4 GtC
Without any knowledge of any natural flow in or out of the atmosphere or changes in such flows, we know that the sum of all natural outflows is 4 GtC larger than the sum of all natural inflows. In other words, the net increase of the atmospheric CO2 content caused by all natural CO2 ins and outs together is negative. There is no net natural contribution to the observed increase, nature as a whole acts as a sink for CO2. Of course, a lot of CO2 is exchanged over the seasons, but at the end of the year, that doesn’t add anything to the total CO2 mass in the atmosphere. That only adds to the exchange rate of individual molecules: some 20% per year of all CO2 in the atmosphere is refreshed by the seasonal exchanges between atmosphere and oceans/vegetation. That can be seen in the above scheme: about 210 GtC CO2 is exchanged, but not all of that reaches the bulk of the atmosphere. Best guess (based on 13C/12C and oxygen exchanges) is that some 60 GtC is exchanged back and forth over the seasons between the atmosphere and vegetation and some 90 GtC is exchanged between the atmosphere and the oceans. These flows are countercurrent: warmer oceans release more CO2 in summer, while vegetation has its largest uptake in summer. In the NH, vegetation wins (more land), in the SH there is hardly any seasonal influence (more ocean). There is more influence near ground than at altitude and there is a NH-SH lag (which points to a NH source). See figure 2:
The net result of all these exchanges is some 4 GtC sink rate of the natural flows, which is variable: the variability of the natural sink capacity is mostly related to (ocean) temperature changes, but that has little influence on the trend itself, as most of the variability averages out over the years. Only a more permanent temperature increase/decrease should show a more permanent change in CO2 level. The Vostok ice core record shows that a temperature change of about 1°C gives a change in CO2 level of about 8 ppmv over very long term. That indicates an about 8 ppmv increase for the warming since the LIA, less than 10% of the observed increase.
As one can see in Fig. 3 below, there is a variability of +/- 1 ppmv (2 GtC) around the trend over the past 50 years, while the trend itself is about 55% of the emissions, currently around 2 ppmv (4 GtC) per year (land use changes not included, as these are far more uncertain, in that case the trend is about 45% of the emissions + land use changes).
We could end the whole discussion here, as humans have added about twice the amount of CO2 to the atmosphere as the observed increase over the past 150 years, the difference is absorbed by the oceans and/or vegetation. That is sufficient proof for the human origin of the increase, but there is more that points to the human cause… as will be shown in the following parts.
Please note that the RULES FOR THE DISCUSSION OF ATTRIBUTION OF THE CO2 RISE still apply!
Typo: should be:
“The problem with that tack is that, of course, it produces scenarios which are absurd and which may therefore be regarded as unrealistic without the realisation that they expose a logical error. “
Slioch:
You and I have often disagreed, so I think it is proper for me to state when we agree.
At August 11, 2010 at 4:49 am you say:
“The mass balance equation does not prove that human emissions are the cause of the rise in atmospheric CO2. The most that can be said from the mass balance equation alone is that human emissions are more than able to explain the rise in atmospheric CO2.
In order to identify human emissions as responsible for the rise in atmospheric CO2 we need additional information from the environment – for example, that no other possible source of CO2 could be responsible (eg. that the volcano does not exist). Such information is not included in the mass balance equation and it alone therefore cannot provide such proof.”
Yes. Indeed, that is a clear summary of the arguments that I presented earlier in the discussion.
Indeed, I think it is the totality of what needs to be said about the mass balance argument: i.e. the mass balance proves nothing concerning whether the anthropogenic emissions are or are not contributing to the observed rise in whole or in part.
Richard
Slioch says:
August 16, 2010 at 3:54 am
Slioch/Richard,
So, the new figures would be:
Annual emission of fossil C to atmosphere = 9Gtons (8Gtons human and 1Gton new volcano)
Annual increase in atmospheric carbon = 4.5Gtons
and we therefore correctly state that the non-human environment is a net sink of CO2.
And you would STILL claim that THIS proves that the increase in atmospheric CO2 is entirely caused by human actions. And it that you would be wrong: in this case one ninth of the increase will have been caused by this new supervolcano.
There are lots of non-fossil inputs into the atmosphere which do contribute to the increase, if taken together with the human emissions. Besides volcanoes, also carbonate rock weathering: more SO2 from volcanoes (and humans…) may increase rock weathering too.
The difference in opinion is where you lump together the natural change with the human change in the inputs. One need to look at the human input separate from all the natural inputs (and outputs).
Without the human emissions there would be an instant reduction of same year CO2 levels in the atmosphere of 3.5 GtC with extra volcano, or 4.0 GtC without extra volcano (the longer term behaviour is for a different discussion). That means that in both cases, there is no increase at all with or without extra volcanic input, only a net loss. All the volcano does is modulating the loss. This can be seen in the natural variability in sink rate, which is about halve the emissions. It doesn’t make a difference if the natural inputs changed or the outputs or both: in all cases, without human emissions: no increase, only a loss. Thus the human emissions still are the sole cause of the increase, but the volcano influences the sink rate and in that way is part of the extra input flow and extra increase, besides lots of other natural inputs which may go up and down.
In summary:
An extra volcanic input would:
– Increase the total natural input with 1 GtC/year
– Increase the total natural output with about 0.5 GtC/year
– The new natural balance then would be -3.5 GtC/year, up from -4 GtC/year
– The human emissions being 8 GtC/year
– The net increase in the atmosphere then is 4.5 GtC/year, entirely caused by the human emissions.
That doesn’t mean that the input didn’t increase, thanks to the volcano, neither that the total CO2 mass in the atmosphere didn’t increase somewhat faster, thanks to the volcano, but again: without human emissions there would be a net loss, no increase at all.
It all is a question of human emissions against the natural world…
Richard S Courtney says:
August 16, 2010 at 4:17 am
Indeed, I think it is the totality of what needs to be said about the mass balance argument: i.e. the mass balance proves nothing concerning whether the anthropogenic emissions are or are not contributing to the observed rise in whole or in part.
In which case you appear to have a very strange idea of what constitutes a mass balance!
Richard
Slioch, I am glad you have returned to the discussion, as I was beginning to understand your position more clearly. Please though could you answer my question which I believe would help to identify the the point of divergence:
Given that we both agree that the natural environment is a net sink, in what respect can it be considered a cause of the observed increase when it has been opposing the increase by taking in more CO2 than it emits?
I said earlier that the mass balance argument demonstrates that the natural environment is a net sink, but it doesn’t prove that the natural environment does not contain components that are not net sources of CO2 into the atmosphere. For me the existence of components that are net sources does not mean that the natural environment is a cause of the observed rise, because we know that other components of the natural environment are even stronger net sinks.
I have also pointed out that there is an obvious distinction between the anthropogenic and the natural, namely it is the anthropogenic that we control, and thus is the obvious means by which any attempts at mitigation will be implemented. You have yet to provide an argument why it is appropriate to seperate out volcanos from other parts of the natural environment (or indeed to lump us in with the natural environment).
As I have pointed out, while the environment is a net sink, any increase in emissions from a component of the natural environment isn’t causing a rise, it is merely weakening the net environmental sink.
N.B. the fossil origin of the carbon is a bit of a red-herring; a fair bit of the anthropogenic emissions is from land use change – i.e. deforestation, which doesn’t involve fossil carbon.
Hi Richard:
But, whilst we agree that the mass balance equation on its own does not prove that human emissions are the only source of the increase in atmospheric CO2, the mass balance equation on its own does show that human emissions are greater than the increase . Therefore it cannot be said that “the mass balance proves nothing concerning whether the anthropogenic emissions are or are not contributing to the observed rise in whole or in part”. If human emissions are positive, which they are, and the change in atmospheric CO2 is positive, which it is, then it is not justified to argue that human emissions are “not contributing” to that increase.
However, in consideration of the above supervolcano scenario, I resile from the statement, “The most that can be said from the mass balance equation alone is that human emissions are more than able to explain the rise in atmospheric CO2.” Since the eruption of the supervolcano resulted in an increase in 0.5 Gton pa in atmospheric carbon, with no change in human emissions, then that sentence would be better written: “The most that can be said from the mass balance equation alone is that human emissions are more than the rise in atmospheric CO2 and have contributed to that rise.”
The best analogy I can think of (using two bits of information I quoted earlier, namely total human emissions from fossil fuels 1850-2000 = 1620Gtons and total increase in atmospheric CO2 during that time = 640Gtons) is this:
The situation is analogous to having a barrel labelled “atmosphere” requiring 640 pints to fill it. If human emissions pour in 1620 pints then the barrel will be full (the rest will “spill” into the oceans and terrestrial biosphere). If at the same time warming oceans pour in some more and volcanoes and unknown source also adds some then it really doesn’t alter the fact that human emissions were more than able to fill the barrel all by themselves.
But to claim in the above analogy that Human Emissions alone caused the barrel to fill is not justified. Such a claim would make it impossible to also acknowledge any increase in atmospheric CO2 that is caused by my above example of a supervolcano eruption.
In my above example of an eruption of a supervolcano (based on annual emissions), a number of important conclusions may bear emphasis:
1. annual human emissions to the atmosphere are still more than the annual increase in atmospheric CO2, ie the natural environment is still a net sink.
2. the supervolcano eruption resulted in an annual increase in atmospheric CO2 of 0.5Gtons.
3. the mass balance equation alone is unable to attribute that increase in 0.5Gtons to the supervolcano.
4. it cannot correctly be said that the totality of the 4.5Gtons pa of atmospheric CO2 have been “caused” by human emissions, since prior to the supervolcano erupting the annual increase was only 4.0 Gtons pa.
Slioch:
“The most that can be said from the mass balance equation alone is that human emissions are more than able to explain the rise in atmospheric CO2.”
As I have pointed out, you don’t need the mass balance quation to know that, you just need to look at the emissions data and the atmospheric CO2 data. The reason that the mass balance argument allows a greater conclusion is becuase the added assumption (conservation of mass) allows us to determine that the natural environment is a net sink.
Now if you can explain in what respect the natural envrionment is a cause of the rise, whilst being a net sink (and hence actively opposing the rise), then I will be in a better position to understand your stance on this.
Ferdinand Engelbeen:
August 16, 2010 at 5:29 am
I’m sorry, Ferdinand, but your explanation is absurd.
I’m not going to spend any more time trying to make you see your error – it is pointless. I’m out.
Slioch: “The situation is analogous to having a barrel labelled “atmosphere” requiring 640 pints to fill it. If human emissions pour in 1620 pints then the barrel will be full (the rest will “spill” into the oceans and terrestrial biosphere).”
This is a misleading analogy as the atmosphere doesn’t have a fixed capacity, and once full the rest doesn’t passively “spill” into the oceans and terrestrial biosphere, it is more the other way round, our emissions that is not actively taken up by the oceans and terrestrial biosphere stays sloshing around in the barrel.
A better analagy would be “we have a barrel of rainwater is shared by two households; one contains a single occupant (Ms Anne Thropogenic) who puts in 8 pints of water a day and takes out nothing. The other houshold, consisting of Mr Nat Uralenvironment who puts in 86 pints a day and takes out 90 and Ms Sue Pervolcano, who puts in 1 pint a day and takes out nothing. Ms Thropogenic notes that the level of water in the barrel is rising more slowly than she is putting water in. She know she is a cause of the rise by her own actions. She also knows (assuming conservation of mass) that the rise was not due to her neighbours. She can’t tell of course if one is a net source and the other a net sink, but is there a good reason to make a distinction between the actions of Mr Uralenvironment from Ms Pervolcano, given that they are both parts of the same houshold?
Say the water in the barrel had some monetary value, how should the profit made by the sale of the excess water be shared between the two housholds?
Slioch says:
“’m sorry, Ferdinand, but your explanation is absurd.
I’m not going to spend any more time trying to make you see your error – it is pointless. I’m out.”
Slioch, why not have a go at answering my question, which will show the divergence in our positions, namely “If the natural environment is a net sink, in what respect can it be considered to be a cause of rising atmospheric CO2”?
Dear Ferdinand,
You say: “In other words: you can’t make dFin positive as long as the emissions are higher than the increase in the atmosphere.”
I think I pointed out that the equation
[15b] 3.5 = 7*0.25 + dFin*0.25 than dFin has a value
7+dFin = 3.5/0.25 . dFin=14-7= 7
also [15b] fulfils the requirement that Fa<FemIN.
And also that the natural circulation is a net sink for dFin + FemIN
What makes you say:
“dFout is 0.4% of the total amount of CO2 in the atmosphere?”
I have no way to calculate a change dFout over the total outflow (FSout) with the order of magnitude, 100-150 GtC/y.
You considered the extreme case:
“Thus in [15] the equation reads:
[15a] 3.5 = 7*(1-0.004) + dFin*(1-0.004) with as result that dFin is much less than 0” (In fact near – 3.5 GtC/y)
What you suggest herewith is that the human emission strongly inhibits the natural inflow at the source (near the equator). We can imagine that an increased CO2 concentration in the atmosphere will have such an effect. (Henry) . But on the other hand this increased concentration will also increase the outflow at the sinks (near the poles). And the inflow by up welling is not only determined by the concentration in the atmosphere, but also by what the up welling water flow brings up. And also by what the down welling water flow takes from the surface. What do we know about these, independently changing flows and their balance?
I can image that by a natural process the total FSin dropped and the total FSout did not increase proportionally, only slightly, leading to a CO2 increase in the atmosphere, without attributing it to the increase of FemIN only.
So far most people have been thinking along the line that an increased natural inflow might be contributing to the accumulation. But it could also be due to a contribution of the reduction of the natural inflow, if the natural outflow does not change much.
If we fill in the original equation
Fa= FemIN(1-x) + dFin(1-x)
For Fa=3.5 and FemIN = 7, a value for x= 0.05 we find for dFin = -3.3
I think that by now that most people taking part in this discussion will not doubt that FemIN is influencing the accumulation process but that the mass balance is no proof that it is the sole cause.
Slioch says:
August 16, 2010 at 6:26 am
Please don’t go away…
If we look to the balance from the output side, one can imagine that the sink rate is reducing over time, if the oceans ability to take in CO2 is reducing. That is one of the themes the IPCC uses to warn us. Thus instead of:
1. annual human emissions to the atmosphere are still more than the annual increase in atmospheric CO2, ie the natural environment is still a net sink.
2. the supervolcano eruption resulted in an annual increase in atmospheric CO2 of 0.5Gtons.
3. the mass balance equation alone is unable to attribute that increase in 0.5Gtons to the supervolcano.
4. it cannot correctly be said that the totality of the 4.5Gtons pa of atmospheric CO2 have been “caused” by human emissions, since prior to the supervolcano erupting the annual increase was only 4.0 Gtons pa.
we then have:
1. annual human emissions to the atmosphere are still more than the annual increase in atmospheric CO2, ie the natural environment is still a net sink.
2. the reduction of ocean uptake resulted in an annual increase in atmospheric CO2 of 0.5 Gtons.
3. the mass balance equation alone is unable to attribute that increase in 0.5Gtons to the decrease in CO2 uptake.
4. even so, it can correctly be said that the totality of the 4.5Gtons pa of atmospheric CO2 have been “caused” by human emissions, even if prior to the reduced uptake the annual increase was only 4.0 Gtons pa.
For a reduced uptake, it is clear that the emissions are the sole cause of the increase. In the case of an increased (volcanic) input, it is intuitively less clear that the emissions still are the sole cause of the increase, but the kernel of our difference in opinion is that for a mass balance, one must put all natural inputs and outputs together and the balance of that shows that nature as a whole is a net sink, thus doesn’t add to the increase…
Ferdinand/Dikran
OK, I’ll try to get back to answer your questions, but it will be a while (twelve hours at least) before I can do so.
Arthur Rörsch says:
August 16, 2010 at 7:21 am
I think I pointed out that the equation
[15b] 3.5 = 7*0.25 + dFin*0.25 than dFin has a value
7+dFin = 3.5/0.25 . dFin=14-7= 7
also [15b] fulfils the requirement that Fa<FemIN.
And also that the natural circulation is a net sink for dFin + FemIN
What makes you say:
“dFout is 0.4% of the total amount of CO2 in the atmosphere?”
I have no way to calculate a change dFout over the total outflow (FSout) with the order of magnitude, 100-150 GtC/y.
You considered the extreme case:
“Thus in [15] the equation reads:
[15a] 3.5 = 7*(1-0.004) + dFin*(1-0.004) with as result that dFin is much less than 0” (In fact near – 3.5 GtC/y)
The basic problem with your equation [15] is that it only looks at the change in inputs and suppose that the outputs follow the inputs with a high rate. But that is not the case:
Suppose that in year one the human emissions are 7 GtC, no change in natural inputs, about 50% of the human emissions are absorbed by nature (3.5 GtC). Year two, the human emissions double to 14 GtC, no change in natural inputs. Do you think that the outputs suddenly double to 7 GtC? Of course that doesn’t happen, as the sink rate is not dependent of the increase in input, but depends of the total amount of CO2 (pCO2) in the atmosphere, which is only slightly influenced by the increased input (800 + 14 – 3.5 – dFout) where dFout may be around 0.2 GtC, due to the increase in delta between the current level in the atmosphere and the “equilibrium” level, but that is rather speculative.
All we know for sure is that at the current level of 800 GtC, the sink rate is about 3.5 GtC/year (2000 figures), that is a sink rate of about 0.4% per year of the total CO2 in the atmosphere. Of all CO2 in the atmosphere, including any (moderate) increase in input, only 0.4% is removed per year. Thus also only 0.4% of any momentary increase in CO2 due to human emissions, volcanoes, ocean warming,… Not 50% or 75%.
The total difference in natural inflow and outflow currently indeed is about 50% of the emissions, but if the emissions would halve or double, that wouldn’t change the outflow more than a few %, which means that the outflow may become 100% or 25% of the new emissions, because momentary changes in input and the correponding change in output would be only weakly coupled, only after a long period, both may come into equilibrium again. The same applies to momentary natural changes.
Anyway, only 0.4% of the total CO2 in the atmosphere is currently removed per year. Thus from any FemIN change or any dFin, only 0.004 parts are removed in the first year. That means that near all momentary changes remain in the atmosphere. And that equation [15a] in your example is mathematically correct, but physically impossible in the current carbon cycle: if 75% of the emissions and 75% of an extra natural input were absorbed in a year, then 75% of all CO2 in the atmosphere would be removed in one year, as the natural world makes no distinction between CO2 which is already in the atmosphere and CO2 which was added in that year.
With such a small real removal rate of CO2, dFin must be (strongly) negative and/or dFout strongly positive, but probably both, as indeed an increase of CO2 in the atmosphere both suppresses the outgassing near the equator as it increases the uptake in the polar oceans…
Do you think that the outputs suddenly double to 7 GtC?
Must read
Do you think that the sink rate suddenly doubles to 7 GtC?
Hi Ferninand,
Thank you for your response. Not at all sure where Bern get their numbers for recoverable reserves of fossil fuels of 3,000 to 5,000Gt. I imagine they are using GtCo2 rather than GtC thereby amplifying the numbers by a factor of three and then adding a 66% fudge factor.
The best numbers I can find for recoverable reserves are natural gas 90GtC, Oil 128GtC, coal 836 GtC, Total 1054GtC. Given that burning/using causes 50% of the C to go to atmospheric CO2 ( the rest goes to cars, boats, planes, packaging , tarmac etc)
that means that the maximum that can be dumped into the biosphere is 500GtC over the next 80 years – not 5000GtC.
With the biosphere weighing in at 43,00GtC the impact has to be trivial.
Typo last line
With the biosphere weighing in at 43,000Gtc the impact has to be trivial
Typo last line
Should read 43,000GtC not 43,00GtC
Ferdinand (FE) says:
FD: “The basic problem with your equation [15] is that it only looks at the change in inputs” My (AR) response:
AR: Not true. The equation [15] is derived from the one that contains de major flow through the system FSin, FSout which is considered to be a standard flow at an assumed equilibrium state FSin = FSout and which is of the order of magnitude of 100-150 GtC/y
Fa = FSin + FemIN+dFin – (FSout+dFout)
From that follows
FA = FemIN+dFin – dFout
FD: “and (the equation) suppose that the outputs follow the inputs with a high rate. But that is not the case”
AR: Not true. Just the opposite. I suppose that the changes in input and output happen independent from each other because they are ruled by the speed of the independent up welling and down welling water flows.
FD: “All we know for sure is that at the current level of 800 GtC, the sink rate is about 3.5 GtC/year (2000 figures), that is a sink rate of about 0.4% per year of the total CO2 in the atmosphere”
AR: Here you demonstrate again the use of your circular argument that a change in natural flows is not involved. So you cannot produce a value of dFout of 0.4 % without using the circular argument.
FD: “Anyway, only 0.4% of the total CO2 in the atmosphere is currently removed per year”
AR: Not true: The total (in and outflow) is of the order of magnitude of 150 GtC/y over an air reservoir of 700 GtC (year 2000 figure), makes the ratio 150/700 = 0.22, or 20 per cent. It indicates a refreshing rate of the atmosphere of 5 – 6 years, a value that today is very well generally accepted. This figure was long ago established from the removal of C14 from the atmosphere after the last nuclear bomb explosion in the atmosphere.
(You have been mixing up changes in in- and output with the total flows.)
FD: “Thus from any FemIN change or any dFin, only 0.004 parts are removed in the first year.”
AR: Wrong (not established) figure used here. But the possibility of such a low figure could be considered. In your former equation Fa= FemIN (1-0.004) + dFin (1-0.004) almost all the FemIN remains in the atmosphere. This could theoretically be the case if the system is operating near its saturation point. I doubt that on two grounds. (a) the annual fluctuation of Fa is of the same order of magnitude of the average value of Fa. Whereas the anthropogenic emission is steady. (b) the amount of anthropogenic CO2 in the mixing layer of the ocean is established at an surprising low level. ( Sabine at al, “The oceanic sink for Antorpogenic CO2”. Science, (305), 16 July 2004, page 367- 371.)
The concentration of CO2 from anthropogenic origin (aC) in the first 100 m layer is at an average of 50 µmol/kg. Since this layer is assumed to contains 2.5 mmol/kg total CO2 (tC), the aC/tC ratio is 0.02.
Lastly I agree with Slioch, (aug. 16,2010 3.54 am) “the mass balance equation is by itself insufficient and why, therefore, SOLE reliance on it to try to persuade people of human responsibility for the increase in atmospheric CO2 is likely to be counter-productive”
The question remains (for me) to what extend? Therefore we have to consider other evidence, but study it also critically whether or not the circular arguments creeps up again.
I also agree with Slioch (aug. 162010 6.26 am): “I’m sorry, Ferdinand, but your explanation is absurd.”. I am looking forward to Slioch’s further considerations within a day or two.
Arthur Rörsch says:
August 17, 2010 at 3:41 am
FD: “Anyway, only 0.4% of the total CO2 in the atmosphere is currently removed per year”
AR: Not true: The total (in and outflow) is of the order of magnitude of 150 GtC/y over an air reservoir of 700 GtC (year 2000 figure), makes the ratio 150/700 = 0.22, or 20 per cent. It indicates a refreshing rate of the atmosphere of 5 – 6 years, a value that today is very well generally accepted. This figure was long ago established from the removal of C14 from the atmosphere after the last nuclear bomb explosion in the atmosphere.
(You have been mixing up changes in in- and output with the total flows.)
Sorry, here is a mixup between total natural in- and outflows of about 150 GtC over the seasons and the remaining net result of these flows at the end of the year. The net result is a 3.5 GtC sink. That is what is known from the calculated emissions and observed increase in the atmosphere. The height of this sink rate may be the result of the pressure of the current atmospheric CO2 mass over the current equilibrium pressure, whatever that might be. That has nothing to do with how much is exchanged with other reservoirs over the seasons, as these seasonal (and partly permanent) flows mostly bring in as much as they remove. Only the difference between all natural inflows and outflows, which is 3.5 GtC net sink, is what removes some of the total mass of CO2 out of the atmosphere at the end of the completed seasonal cycle. Thus from the 700 GtC in the (2000) atmosphere, only 0.5% is really removed into other reservoirs, even if 22% of all CO2 in the atmosphere is exchanged with CO2 from other reservoirs within a year.
The removal rate for the year 2000 is 0.5%.
The refresh rate for the year 2000 is 22%.
Refresh rate and removal rate have very little in common…
FD: “All we know for sure is that at the current level of 800 GtC, the sink rate is about 3.5 GtC/year (2000 figures), that is a sink rate of about 0.4% per year of the total CO2 in the atmosphere”
AR: Here you demonstrate again the use of your circular argument that a change in natural flows is not involved. So you cannot produce a value of dFout of 0.4 % without using the circular argument.
Even if some natural in and outflows doubled or halved, that doesn’t matter. The 3.5 GtC is what is known as the net result of all these flows, as that is the difference between the calculated emissions and the measured incease in the atmosphere. The 700 GtC (2000) also is measured, thus the 0.5% is simply dividing two known values, nothing circular here.
This difference in opinion must be resolved first, before we can further discuss the other equations…
Dear Ferdinand,
Concerning your comment, 3.5 GtC/y NET sink over the volume in the atmosphere 700 GtC, you may have a point. (A point I missed and interpreted wrongly). What you say here is: if you inject into a clean atmosphere 7 GtC/y (aC), it is so much diluted that a small fraction of it can only go out with a mainstream out of 150 GtC/y. I calculated meanwhile, from the first 7 GtC/y, goes out 1.22 GtC/y only. That is a fraction 0.17 from the 7 GtC/y input. But in the next years, when more aC is accumulating in the atmosphere, also more will go out. And it rises quickly with the years. I still have to check my calculations (with a constant standard input output of 150 GtC/y in the natural cycle) but you can imagine the principle. If I am not mistaken, then after 10 y input of 7 GtC/y, the ratio rises to aCout/aCin = 0.8 .
But this approach is very different from your original one, stating the mass balance as proof that most of the aC is accumulating.
Few people on this blog show an interest in our calculations. Your other opponents use different arguments. Therefore I propose we continue our discussion between the two of us (or with a third party which shows some interest and is willing to join) . Probably we can come up together with a theoretical model, how much of the aC is contributing to the accumulation in the atmosphere and what the influence of a natural changing cycle may be.
I am certainly willing to consider from the theoretical point of view that the aCin has a major influence. But by intuition I find it difficult to imagine that in my equation with a strong influence of aC, the natural inflow could have been reduced with 3 or more GtC/y to make up the balance you proposed (see also your figure 3).
Arthur Rörsch says:
August 17, 2010 at 12:38 pm
I calculated meanwhile, from the first 7 GtC/y, goes out 1.22 GtC/y only. That is a fraction 0.17 from the 7 GtC/y input.
I fear that you are confusing the origin of the molecules and the origin of the increase in mass …
The full 7 GtC aCO2 from the human emissions is going into the atmosphere. Some 150 GtC (in first instance all natural nCO2) is mixed into the atmosphere, while 153.5 GtC of the mixed atmosphere (700 nCO2 + 7 aCO2) is absorbed, thus containing 1% aCO2, or 1.5 GtC aCO2 which is removed into other reservoirs.
That makes an increase in total mass of 3.5 GtC, which is fully attributable to the anthro CO2 emissions, despite that part of it already is removed by the refresh rate. But the refresh rate only exchanges molecules CO2 in the atmosphere with molecules CO2 from other reservoirs, it doesn’t change the total mass of CO2 in the atmosphere, except for the 3.5 GtC difference in inputs and outputs which is a net sink. The final increase of aCO2 in the atmosphere after a year at the other hand is 7 – 1.5 = 5.5 GtC on the total 703.5 GtC in the atmosphere, or 0.8%.
The second year is more problematic to calculate for attribution of the origin of the molecules, as part of the absorbed CO2 in the ocean’s mixed layer and vegetation simply returns in the next year (even already in the next season!). Only the deep oceans are still aCO2 free in the upwelling zone. If we use that to calculate the deep ocean – atmosphere refresh rate, we come to some 40 GtC exchange between the deep oceans and the atmosphere (based on d13C reduction).
Anyway, the attribution of the increase in mass in the second year still (in our opinion) remains 100% caused by the human emissions, as the emissions -again- are larger than the sink rate while the relative increase in aCO2 in the atmosphere depends on the refresh rate. Two more or less independent mechanisms. Thus even if in the future years a relative lager part of aCO2 is “outrefreshed”, that doesn’t change the fact that for each year that the emissions are larger than the increase in the atmosphere, the emissions are fully responsible for the increase.
But by intuition I find it difficult to imagine that in my equation with a strong influence of aC, the natural inflow could have been reduced with 3 or more GtC/y to make up the balance you proposed (see also your figure 3).
I suppose that in reality, because of the CO2 increase, that the release at the equatorial oceans is somewhat reduced, but tha the bulk of the difference is in enhanced uptake at the cold parts of the oceans and by vegetation.
Indeed, I suppose that there are not many lurkers are left here. Time for part two…
The Mass/Balance Equation was presumably introduced in an attempt to bring clarity and useful insights. While it may intuitively be an attractive proposition it is of limited use as an analytical tool. For one thing the error ranges on the large items completely swamp the small items that are of interest.
As an analogy it is like trying to analyse a major corporate with a single line Cash/Balance equation. It will balance alright but it is a pretty ugly way to do it.
Can I suggest that some tools be borrowed from the second oldest profession. What is needed is a start and end Balance Sheet (I have found they need to be at least a decade apart as the time frame of climate is a bit longer than a company) and a C Flow Statement for the period. Once all these numbers are agreed balanced and published, a sensible analysis and debate can begin.
Jim McK
“The Mass/Balance Equation was presumably introduced in an attempt to bring clarity and useful insights. While it may intuitively be an attractive proposition it is of limited use as an analytical tool.”
No, you will find it mentioned in the IPCC reports and many peer reviewed articles on the carbon cycle. The only evidence for a “missing sink” which has been the concern of carbon cycle research for a decade is from the mass balance argument, which shows that natural uptake must be larger than we could account for given the state of knowledge/uncertainty of indivudual fluxes.
“For one thing the error ranges on the large items completely swamp the small items that are of interest.”
No, that is incorrect, the mass balance argument estimates the net environmental flux from emissions data and atmospheric CO2 data, both of which are known with good certainty, not estimates of the natural fluxes (which are uncertain). The emissions data would need to be wrong by a factor of 100% before it changed the conclusion of the mass balance argument, and the uncertainty is nowhere near that large.
To add:
“Can I suggest that some tools be borrowed from the second oldest profession. What is needed is a start and end Balance Sheet (I have found they need to be at least a decade apart as the time frame of climate is a bit longer than a company) and a C Flow Statement for the period. Once all these numbers are agreed balanced and published, a sensible analysis and debate can begin.”
That is pretty much exactly how the mass balance argument procedes. The data are all available from the Carbon Dioxide Information Analysis Center. If you want to recalculate on a decadal rather than an annual timeframe, the data is there for you to do so; you will get the same result.