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!
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Friends:
Having left this discussion but continuing to observe it, I write to express my delight at observing that Arthur Rorsch has joined the debate.
Arthur is probably the most open-minded scientist it has been my privilege to be associated with since I first became profesionally involved in the practice of scientific research in the mid 1960s.
If anyone can cut through the ‘Gordion knot’ that has tied this debate to a standstill of opposing views then he can.
Richard
Far be it from me to presume to mediate, but it is one of my vocations. A most fabulous post and discussion. All commenters are to be applauded for the civility of the discourse. True peer review is in evidence. Both sides have stated their positions quite clearly for all to consider.
Science, however, is not a democracy. It only takes one vote to win. That vote is the Truth. When Truth casts its vote, science adapts and moves on. I think truth is about to cast its vote on this issue. Why? Because both sides are still listening to each other. Maybe unwillingly, but they are listening. We have Anthony and WUWT to thank for this. An idea whose time has come! Science and human endeavor can only benefit from this approach. And the conclusion/solution/resolution will be documented for posterity (until the next asteroid stike anyway (but maybe we’ll quickly figure out how to deflect the asteroid!?)).
I humbly suggest that we move to Part 2.
Ralph Dwyer
Richard S Courtney,
I am glad to see you come back too. I wish I could have continued our discussion at Jo Nova’s site but she filters all my posts now.
I enjoy seeing you try to rebut anything that might suggest CO2 is warming the planet no matter what the evidence.
To see how you argue that our emissions are inconsequential because natural variation is an order of magnitude larger is just amazing! (although perhaps not for the reasons you might be thinking) 😉
But I have to agree, just because we’re emitting more CO2 than ever before doesn’t mean it’s ours up there in the atmosphere. Although it might seem that way, because our emissions are always a positive contribution whilst natural variation seems to be close to balanced, you can’t tell for sure without looking at other evidence.
Perhaps the fact that CO2 hasn’t been this high for at least a few hundred thousand years adds a bit more weight to the argument. The 14C/12C ratio also seems to go against your desires.
I look forward to hearing your thoughts on these!!
“… add nothing to available knowledge concerning what I want to know.” <– at least you're open minded. 😉
Ralph Dwyer says:
August 8, 2010 at 6:33 pm
I humbly suggest that we move to Part 2.
I agree that most is said and the different points of view are clearly stated. I am a little in doubt if I would discuss the reliability of ice cores, other proxies and historical data first, before more fundamental items, as these pop up frequently in all debates.
Anyway, herewith I thank Anthony for the opportunity to debate this controversial item within the sceptic’s world with a lot of interested (and interesting) people. This kind of debate seems impossible in “consensus” world…
REPLY: that is the highest complement anyone could make for this forum, thank you. – Anthony
Ferdinand, whilst a discussion of ice core, stomatal and historic measurements would cause a huge firestorm of discussion I think it is important to do so. One of the issues at the heart of the present debate over the mass balance approach is the hypothesis that CO2 levels have fluctuated rapidly in the recent, historic past, and that we cannot trust the ice core measurements.
I am sure the ice core measurements for the most part are robust and, given corrections for gas age, are consistent with the modern IR measurements at, for example, Hawaii. I’m not sure how the historic measurements fit in, but suspect they may be affected by local effects associated with photosynthesis and plant respiration. You have to move a considerable distance away from vegetation, either vertically or horizontally to minimise these effects.
Having said this, however, I would be very happy to see a wider discussion.
Many thanks for setting down clearly your views for others to talk about.
Ferdinand Engelbeen says:
August 8, 2010 at 11:48 am
“Paul, if the vulcanism increased suddenly up to 300 times the current estimate, that is three times the current human emissions, and everything else remained constant (including sink rates), what would the increase of CO2 in the atmosphere do?”
We do not know. It depends, first, upon when this increase occurred, how rapid the increase was, and how long it lasted. Second, it depends upon where this increase occurred, how rapidly it was distributed and how far it went. Third, it depends upon what reaction there was to the increase on the part of all the other components of the carbon cycle system (including the human components). Your assumption that everything else remained constant is a nonsense.
So when you say: “I suppose that you agree that the total increase at the end of the first year would be:
8 GtC (emissions) + 24 GtC (volcanic) – 4 GtC (current sink rate) = 28 GtC increase in the atmosphere.”
my answer is NO, this is a non sequitur, the same error that dogs your whole thesis.
I have to wonder whether Ferdinand & Co are Georgists, because their arguments are almost perfect parallels. The mass-balance argument is almost identical to the notoriously fallacious argument by which Henry George “proved” that Rent on Land was to blame for all the evils of the world. They debate like Georgists too. Hard-pressed, they slide away into slightly different claims, subtle shifts of meaning, or endless appeals to irrelevant details, thereby avoiding the immediate charge, then, when the pressure is released, slide back again to the old fallacy. All this is the sign of a “crank” doctrine, not science. It’s not the original conjecture that’s unscientific – it might even be substantially correct – but the manner in which it is believed and defended. Unfortunately, even the hard evidence that might provide good confirmation or disconfirmation of the theory is then filtered through the veil of the underlying logical error, and so becomes worthless, confusing and confounding rather than enlightening.
Paul Birch,
I’m trying really hard to understand the difficulty others are having with the mass balance argument posited by Ferdinand Engelbeen here. Leaving that aside for the while there are other empirical data to which we have recourse. Namely measurements of the oxygen level of the atmosphere, 14-C systematics and 13C/12C stable isotope ratios. The results of the mass balance model, namely that the modern rise in atmospheric CO2 can be attributed to anthropogenic inputs with approximately 50% of these being taken up by oceanic and other sinks, is consistent with these other observations. I’m not sure if there exists, and certainly have never seen any other explanation that is consistent with all these empirical observations. Can you point me to any?
I’m open to being proved wrong on this but I suggest that Ferdinand and Dikran have stated the mass balance argument with absolute clarity and have been steadfast in their defence of it without recourse to sophistry of any kind.
Paul Birch wrote:
“I have to wonder whether Ferdinand & Co are Georgists, because their arguments are almost perfect parallels. The mass-balance argument is almost identical to the notoriously fallacious argument by which Henry George “proved” that Rent on Land was to blame for all the evils of the world. They debate like Georgists too. Hard-pressed, they slide away into slightly different claims, subtle shifts of meaning, or endless appeals to irrelevant details, thereby avoiding the immediate charge, then, when the pressure is released, slide back again to the old fallacy.”
Actually, no the claim is exactly as stated througout the thread. The mass balance argument established the the net environmental contribution to theobserved rise is negative. That has not changed one iota, simply because it is true (unless somehow conservation of mass is violated).
No additional details have been introduced (although Ferdinand and I have answered points made by the opposing side of the argument when they have arisen).
” All this is the sign of a “crank” doctrine, not science. It’s not the original conjecture that’s unscientific – it might even be substantially correct – but the manner in which it is believed and defended.”
It is rather a pity that after Ferdinand complemented the manner in which the discussion had been conducted that you choose that point to suggest that those who oppose your position are “cranks” and non-scientific.
“Unfortunately, even the hard evidence that might provide good confirmation or disconfirmation of the theory is then filtered through the veil of the underlying logical error, and so becomes worthless, confusing and confounding rather than enlightening.”
Blah blah blah.
I have twice now given a challenge to those who assert that the rise can be natural in origin to specify values for the fluxes comprising the carbon cycle such that the net contribution of the natural environment is positive AND such that the resulting rise in atmospheric concentrations is less than anthropogenic emissions. Never mind the uncertainty of specific fluxes, such a scenario is numerically impossible assuming conservation of mass. Go ahead prove me wrong.
That is a purely scientific approach (according to Popper). I have stated exactly how you can falsify the hypothesis, all you have to do is choose about a dozen positive numbers. I don’t even require that they should be realistic of the real carbon cycle, just demonstrate that it is numerically possible.
Ferdinand and Dikram,
Your hypothesis is not valid. The division of emissions into human and natural is false. Many human emissions of could be considered natural. They have replaced and could be replaced by what we call natural emissions.
For example, people burn wood, if it had not been collected by a man it would still have burned, or been eaten by termites. Then it would be according to your carbon cycle, a natural emission.
Your carbon cycle is faulty, leads to wrong conclusions and allows you to argue in circles
Roger,
“Your hypothesis is not valid. The division of emissions into human and natural is false. Many human emissions of could be considered natural. They have replaced and could be replaced by what we call natural emissions.”
Respectfully, you are wrong here. The division is not between human and natural. What you are calling human is actually based on the fossil fuel inventory and does not include the burning of, for example, wood. This would be classed as a natural, or environmental input.
After much thought I think the debate focuses on one aspect. Those who don’t agree with Ferdinand and Dikram’s analysis are implicitly posing a question about the possibility of “anthropogenic sinks” that are not being accounted for. It is implicit in Ferdinand’s and Dikram’s analysis that such sinks are not significant.
There is empirical evidence for this if one analyses the oxygen content of the atmosphere as a function of CO2 content. Here we can identify the key sinks for the excess CO2 as being oceanic dissolution and photosynthesis. There is no evidence of a hitherto unnoticed anthropogenic sink.
I think Dikram possibly pointed this out earlier but need to go back through all the contributions to be sure.
Roger Clague: Anthropogenic land use changes form part of anthropogenic emissions, which includes deforestation. So if old-growth forests are cut down for firewood, that IS included already in anthropogenic emissions. If it isn’t old-growth forest (i.e. it is “farmed” and is replaced) then there is no net long term contribution.
In old growth forests the CO2 released by termites or forest fires is balanced by CO2 taken in by new growth. However if you cut down the forest for firewood, there is no new growth to balance the emissions.
HTH
Dear Paul Birch,
You say about George Engelbeen, “that the doctrine may even be substantially correct”. I am inclined to say so too. With a chosen parameterisation of the equations for absorption from the atmosphere all three models we used, match with the MLO data over the period 1959-2000, if we assume that the anthropogenic emission is the sole cause of the gradual CO2 increase in the atmosphere over this period. But here starts the circular argument. If the parameterisation is not correct, because another source is contributing, than the doctrine does not hold. And with IPCC reasoning and use of parameterisation with models in our mind, we have to be very careful about the use of any model.
Next Dikran Marsupial is correct that de environmental contribution to the observed rise is negative. But he is not correct that any other unbalance, caused by the contribution of another source, would be a violation of the law of mass conservation. I have shown that in the table of my previous post.
dFout dFin dFin-dFout
3.50 0.00 -3.5
5.14 1.64 -3.5
6.75 3.25 -3.5
8.36 4.86 -3.5
9.96 6.46 -3.5
11.57 8.07 -3.5
13.18 9.68 -3.5
14.79 11.29 -3.5
16.39 12.89 -3.5
(The values for dFin above 0 represent the contribution of an (hypothetical) additional source to maintain the same value for dFin and dFout.)
Question: why are we interested in the investigation of a possibility of an additional source? The answer for me is, because we want to understand better the variability of CO2 cycles over longer periods than decennia. I am not really interested in the question whether the current CO2 rise is only Man-made. If it is, the atmosphere is than probably the safest and most useful place to store it in a diluted form.
PS I noted that if I transfer text from the blog into a Microsoft Word document, it appears in the letter type Giorgia. May be we are considered to be all Giorgists. Or are blog discussions by definition Giorgism?
Roger Clague says:
August 9, 2010 at 5:29 am
Ferdinand and Dikram,
Your hypothesis is not valid. The division of emissions into human and natural is false. Many human emissions of could be considered natural. They have replaced and could be replaced by what we call natural emissions.
For example, people burn wood, if it had not been collected by a man it would still have burned, or been eaten by termites. Then it would be according to your carbon cycle, a natural emission.
As already said somewhere in the 400+ reactions here: wood burning or food eating by humans is not considered as contributing to the human emissions, as the carbon contained in it was captured from the atmosphere in previous months/years.
It is the burning of fossil fuels, buried many millions of years ago in a quite different atmosphere, which makes the difference: that adds one-way to the current atmosphere, without fast compensation.
Paul Birch says:
August 9, 2010 at 3:32 am
my answer is NO, this is a non sequitur, the same error that dogs your whole thesis.
You simply are avoiding a straight answer.
Please show us, as Dikran asked, that one can have a real contribution of nature to the increase in the atmosphere while the net result is less than the human emissions.
Dikran Marsupial says:
August 9, 2010 at 6:02 am
In old growth forests the CO2 released by termites or forest fires is balanced by CO2 taken in by new growth. However if you cut down the forest for firewood, there is no new growth to balance the emissions.
Indeed, forgot to include land use changes of old growth forests: these are normally in break-even or slighltly sinks for CO2. If you cut them whithout new growth or agriculture only (decreased carbon storage), that should be included in the emissions…
Dear Ferdinand,
Did not I provide the answer on the ‘balance?
Note a mistyping in my previous post
(The values for dFin above 0 represent the contribution of an (hypothetical) additional source to maintain the same value for dFin and dFout.)
Should read with a minus sign:
(The values for dFin above 0 represent the contribution of an (hypothetical) additional source to maintain the same value for dFin – dFout.)
Arthur Rörsch says:
August 9, 2010 at 6:03 am
Dear Arthur,
I was thinking a little further about your “two unknown” variables in your comments:
In fact there is only one unknown variable, as your own list of possibilities shows: the difference between the two unknowns is known, thus the knowledge of the input (or change in input) automatically fixes the output or reverse (for each year in the past 50 years).
Further, the absolute height of the input (or the output) doesn’t influence the total amount of CO2 in the atmosphere. It is the difference between the two which is important, as any change in the sum of the inputs must be compensated by an equal change in the sum of the outputs to obey the mass balance for a given year.
What you are doing is looking at an increase of the inputs as “extra” input and separate that from the equally large increase in outputs.
Any increase in one of the natural inputs indeed adds to the total mass of inputs, but doesn’t add to the total amount in the atmosphere, as long as the outputs need to increase with the same amount…
Arthur Rörsch says:
August 9, 2010 at 6:03 am
With a chosen parameterisation of the equations for absorption from the atmosphere all three models we used, match with the MLO data over the period 1959-2000, if we assume that the anthropogenic emission is the sole cause of the gradual CO2 increase in the atmosphere over this period. But here starts the circular argument. If the parameterisation is not correct, because another source is contributing, than the doctrine does not hold.
The mass balance doesn’t include any parameterisation and must hold for any combination of inflows and outflows and changes thereof. If you start with parameterisations, then indeed you are getting on thin ice…
Ferdinand Engelbeen says:
August 9, 2010 at 6:15 am
Paul Birch says: “my answer is NO, this is a non sequitur, the same error that dogs your whole thesis.”
Ferdinand says: “You simply are avoiding a straight answer. ”
The straight answer is NO. There could not be a straighter answer.
“Please show us, as Dikran asked, that one can have a real contribution of nature to the increase in the atmosphere while the net result is less than the human emissions.”
I’ve answered that many times over, both directly and through simple analogies using water flows.
There is “a real contribution to nature to the increase in the atmosphere while the net result is less than human emissions” if the atmospheric concentration would still have risen in the absence of human emissions. You yourself have admitted that this would have happened to some extent, as a consequence of the temperature rise over that period. How much is a quantitative question that depends up details of the various reservoir sizes, mixing rates, heat capacities and temperature dependences of the various solubilities, chemical equilibria and biological responses.
The level of water in a lake is determined by the amount of rainfall. The level of water in a drain is determined by the level of water in the lake, and thus by the amount of rainfall. The level of water in the drain is not determined by the quantity of water poured down it by a factory – not even if the increase in volume of water in the drain is less than the amount of water poured into it. The drain is the atmosphere. The lake is the other CO2 reservoirs, like the oceans, biosphere and sea floor. Rainfall is all the non-anthropogenic sources (note that it makes no difference to the argument if some of the rainfall goes down the drain, as well as the factory output).
Paul Dennis says:
August 9, 2010 at 4:38 am
“Paul Birch, I’m trying really hard to understand the difficulty others are having with the mass balance argument posited by Ferdinand Engelbeen here. Leaving that aside for the while there are other empirical data to which we have recourse. ”
Unfortunately, such empirical data are worthless while the debate continues to be framed on the basis of a fundamental logical error. Through that prejudicial error, the whole analysis has a built-in dogma that assumes the very conclusion to be tested.
So a short summary of how human CO2 has been claimed to cause all the rise.
* The average increase of 2 ppmv of CO2 over period measured by instruments.
* This calculates to a 4 GtC on a yearly basis.
* With 8 GtC emissions from humans thats means 4 GtC are missing.
* The oceans absorbed the missing 4 Gtc because we can’t find them.
* Bingo and conclusion, all the rise in emissions in the atmosphere are from humans.
No consideration of any natural changes in gasous exchange of CO2 over the period whats so ever because these are persumed to stay the same.
Is this just me (obviously not) or this idea scientifically flawed and not how science should be examined and anaylised?
Arthur Rörsch writes:
“Next Dikran Marsupial is correct that de environmental contribution to the observed rise is negative. ”
I really don’t understand how someone can agree that the net envrionmental contribution to the rise is negative (i.e. the environment has been removing more CO2 than it puts in) and yet not accept that the natural environment therefore cannot be a cause of the rise. However, agreement on the fact that the net contribution to the rise is negative is a major step forward in the discussion.
“But he is not correct that any other unbalance, caused by the contribution of another source, would be a violation of the law of mass conservation.”
No, that is not correct. It would only be a violation of the law of conservation of mass for the envrionment to make a positive net contribution to the rise IF the observed rise is less than anthropogenic emissions.
If the observed rise was greater than anthropogenic emissions, the mass balance argument would indicate that both man and the natural environment were contributing to the rise. But that is not what the observations show.
The key point is, that the uncertainty on the magnitudes of the environmental fluxes do not affect the mass balance argument. The net environmental contribution is computed from the observed rise and anthropogenic emissions, using the principle of conservation of mass. This means the uncertainty of the estimate of the net contribution depends on the uncertainty of the observed atmospheric CO2 levels and of anthropogenic emissions, NOT the uncertainties of our estimates of the magnitudes of the environmental fluxes.
Paul Birch says:
August 9, 2010 at 8:12 am
I’ve answered that many times over, both directly and through simple analogies using water flows.
There is “a real contribution to nature to the increase in the atmosphere while the net result is less than human emissions” if the atmospheric concentration would still have risen in the absence of human emissions. You yourself have admitted that this would have happened to some extent, as a consequence of the temperature rise over that period.
That is the fundamental difference in our opinions:
The temperature would have increased the CO2 level in absence of human emissions. But it didn’t, because there were human emissions which were much larger than the observed increase (except for the period 1850-1900). What Arthur, Richard and you do, is looking at (extra) natural inputs separated from the outputs and assume that these add to the increase. In that case all inputs are equal and human emissions are peanuts compared to the natural inputs.
But that is a wrong comparison: human emissions are hardly influenced by human sinks, while natural inputs are more than compensated by natural sinks. One need to compare the net contribution of humans with the net contribution of nature…
The level of water in a lake is determined by the amount of rainfall. The level of water in a drain is determined by the level of water in the lake, and thus by the amount of rainfall. The level of water in the drain is not determined by the quantity of water poured down it by a factory – not even if the increase in volume of water in the drain is less than the amount of water poured into it.
Sorry, that is completely wrong: as long as there is some resistance in the pipeline between the drain and the lake, both the level in the lake (influenced by rainfall) and the quantity added by the factory will affect the level in the drain, as any process engineer can tell you.
The drain is the atmosphere. The lake is the other CO2 reservoirs, like the oceans, biosphere and sea floor. Rainfall is all the non-anthropogenic sources (note that it makes no difference to the argument if some of the rainfall goes down the drain, as well as the factory output).
As long as there is a time factor in the uptake of extra CO2 from the atmosphere into other reservoirs (as is the case for both deep oceans and vegetation), then both the natural and anthro sources and sinks will influence the CO2 level in the atmosphere. In the case that the increase in the atmosphere is less than the net human emissions, then the net contribution of the natural exchanges is negative…
Mat G: The result stems from an application of the principle of conservation of mass to the observations. The principle of conservation of mass is very widely used in science, added to which it is intuitively obvious.
Now if you don’t think the excess anthropogenic carbon (the part that doesn’t end up in the atmospher) isn’t taken up by the natural environment (not just the oceans), then can you explain where it has gone?
If you think the argument is incorrect, a counter example would be the easiest way to prove it. Just give a set of positive values for the fluxes shown in figure 1, for which (i) the natural environment makes a positive net contribution and (ii) the resulting rise in atmospheric CO2 (assuming conservation of mass) is less than anthropogenic emissions. This is now the fourth time I have made that challenge – no takers so far, but I have an open mind, all I need is a correct counter-example to make me change it.