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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Richard S Courtney said:
““The mass balance argument does not assume that a change in input will automatically be reflected in a change in the output. The only assumption it makes (regardless of what Richard S. Courtney and others keep asserting) is that any carbon entering the box representing the atmopshere that doesn’t leave the box, stays in the box. In other words, there is conservation of matter.”
No!
I do NOT dispute that “any carbon entering the box representing the atmosphere that doesn’t leave the box, stays in the box”! And you cannot cite or quote any occasion when I have disputed it because I never have.”
I think you have misread the paragraph that you have just quoted. In it I assert that the mass balance argument makes only one assumption (namely conservation of mass), but that others (including yourself) have asserted that it involves other assertions as well. This does not in any way imply that you dispute mass balance (that would be absurd). The structure of the sentence as written makes that perfectly clear.
Your own reply demonstrates that you do assert there are other assumptions (as I said). If we both agree that the assumption of conservation of mass is valid, then the invalid assumptions you mentioned in earlier posts must be something else.
Now you appear to have got a bit hot under the collar. I would greatly prefer it if the discussion could be conducted without accusations of dishonesty etc. It does nobody any good, and is not the way a scientific discussion should be conducted.
Now I have explained why conservation of mass is the only assumption made by the mass balance argument. It is now down to you to demosntrate the step in the chain of reasoning where these additional invalid assumtions that you have mentioned are implicitly introduced. If you want to discuss it in an even tempered manner, I would be happy to participate.
Thanks for answer Ferdinand.
What CO2-compound is included in nDIC besides the carbonates that are in equilibrium with Co2? We are talking about upper ocean layers and thus carbonates sedimenting is not in question.
By the way: I really agre with Ernst Beck that his later collected data strongly suggests higher Co2 levels around 1940:
http://hidethedecline.eu/pages/posts/co2-carbon-dioxide-concentration-history-of-71.php
I mention this again (and again) because a higher CO2 level before human emissions accelerated appears to be a problem for your point of views.
Beck did some rather “fresh” conclusions in the beginning, so ever since this has haunted Becks newer material no matter how strong his newer material is. I think its time we reconsidder CO2 levels around 1940.
K.R. Frank Lansner
Paul Birch: If we are trying to find out if the rise is natural or man made (or both), then the natural environment can be treated as being a single entity. That is obvious from the form of the mass balance argument.
If the natural environment as a whole is a net sink, then it isn’t the cause of the rise, as even if some part of it is emitting more than it takes in, there is some other part of it that more than compensates.
The rise being man made means that:
(i) man is a net source of CO2 to the atmosphere (establishing it as A cause of the rise)
(ii) the natural environment (as a whole) is a net sink, and has opposed the rise (establishing that it is not a cause of the rise)
(iii) as there is only us and the natural environment (as a whole), we must be the only cause of the rise.
(i) is obvious, (ii) is established by the mass balance argument (iii) is an obvious corollary of (i) and (ii).
Ferdinand Engelbeen says:
August 7, 2010 at 7:56 am
Paul Birch says: “I have to wonder what Ferdinand & Co think they mean by saying “the CO2 increase is man made”.
What any normal scientist or English speaker would understand by the claim is:”
Ferdinand says: “Depends what you mean by a “scientist”, and English is not my native language (it’s Flemish/Dutch)…”
Which is why I am prepared to allow that you might not quite understand the wording you’re using, so I am asking for clarification on what you think you mean, as distinct from what the English actually means.
Paul: “1) CO2 levels would not have increased if man had not emitted this CO2.
It doesn’t necessarily imply they would have stayed the same – they could have fallen – but if they would have risen at all then we could only say “part of the CO2 increase is man-made”.”
Ferdinand: “Agreed on the first part, disagreed on the second part:
CO2 levels would not have increased if man had not emitted this CO2. That is at least true for the past 50+ years and highly probable for the past 100+ years. Besides a small contribution (about 8 ppmv) from the temperature rise since the LIA, all of the increase is man-made.”
Well, I don’t quite know what you mean by “disagreed on the second part”, but you appear to be have switched back to arguing about the empirical facts, not what the phrase means. Do you in fact understand what “would” and “could” mean in English, that they describe conditionals, counterfactuals or hypotheticals? If you haven’t realised this, it may be one of the sources of the confusion.
Notwithstanding this question, you do now seem to be re-affirming that by “the CO2 increase is man made” you do mean (1) “CO2 levels would not have increased if man had not emitted this CO2”. If so, that’s absolutely fine.
But in that case your mass balance argument is totally invalid as a means of proving it, because there is no way it can answer the question of what would have happened in different circumstances. What would have happened matters – and needs to be proved before you can assign causation.
Paul: “3) CO2 levels have risen by no more than the amount of CO2 man has added to the atmosphere.”
Ferdinand: “No. That is flatly contradicted by the mass balance: CO2 levels have risen less than the amount of CO2 man has added to the atmosphere. And that is what makes that our interpretation of 1) is true.”
Once again, it seems your knowledge of either English or logic is letting you down. There is no contradiction between these two statements. Your statement “levels have risen less” is included in mine “levels have risen no more”. If you wish to exclude the equality “levels have risen neither more nor less” from your argument, that’s a more stringent requirement, but it’s up to you: are you now saying that if the level had been rising at a rate equal to that at which man has been adding CO2 the increase would not be man made?
Richard S. Courtney: wrote
“I dispute your assertion that the only input to the “box” that effects the mass
balance is the anthropogenic emission because – you assume – the carbon cycle is invariate. But I keep pointing out that THE NATURAL INPUTS AND OUTPUTS TO THE “BOX” VARY BY UNKNOWN AMOUNTS, so the mass balance argument is complete bunkum.”
Yes, exactly what I said, you assert that I have made assumptions other than conservation of mass.
The mass balance argument does not assume that the carbon cycle is invariate, of course natural sources and sinks vary and the actual fluxes are very uncertain. I have pointed out that the mass balance argument does not depend on the value of these fluxes. I’ll explain again. We agree about conservation of mass, so I assume you agree that
dC = E_anthropogenic + E_natural – U_natural
where dC is the change in atmospheric CO2, E_anthropogenic is anthropogenic emissions (assuming anthropogenic uptake is negligible), E_natural is total natural emissions (all natural sources – including subsea volcanos) and U_natural is total natural uptake.
A simple rearrangement gives:
E_natural – U_natural = dC – E_anthropogenic
so if you know dC and E_anthropogenic, you can work out (E_Natural – U_natural).
We have not assumed anything about E_natural or U_natural, not even that they are constant. All we are doing is indferring this net natural flux (over the observation period) from two quantities that we can measure with good accuracy.
This demonstrates that your claim that I assume the carbon cycle is invariate is not correct. We don’t need to know anything about the magnitude of the natural fluxes, we are only interested in the net flux, and you can work that out with a bit simple algebra, using one assumption – conservation of mass.
Paul Dennis says:
“Ferdinand Engelbeen is not making the assumption that the natural fluxes are invariant. He is merely pointing out that the rise in atmospheric CO2 levels is less than the anthropogenic flux to the atmosphere. The only solution under these conditions is that the rise is caused by the antropogenic flux. It so happens that about 50% of this flux is partitioned into the oceans and the terrestrial biosphere, with 50% remaining in the atmosphere.”
yes, spot on.
Ferdinand Engelbeen says:
August 7, 2010 at 9:00 am
quote
Oceans are the largest sinks and sources of CO2 and they are by far not saturated.
The upper ocean layer is certainly saturated and only by increasing the amount of CO2 in the atmosphere, or cooler oceans, one can push more CO2 into the oceans (and reverse for warmer oceans or less CO2 in the atmosphere).
unquote
The only paper I’ve seen that claims that the ocean upper layer is saturated did its research in shallow waters where wave action might be expected to make the atmosphere and water well mixed. It also had caveats about the measurements being difficult .
Maybe we have slowed the ocean’s uptake and are now moving to a higher partial pressure of CO2 in the atmosphere to counter our restriction.
Ferdinand, I know you like correlations — could you have a look at the size of the petro-chemical industry vs the CO2 increases? It’s something I’ve wondered about.
JF
Frank Lansner says:
August 7, 2010 at 10:33 am
quote
We are talking about upper ocean layers and thus carbonates sedimenting is not in question.
unquote
Google Emiliania huxleyi for a counter example. This produces calcium carbonate in such quantities that the blooms show up from space as vast milky plumes.
JF
Dikran Marsupial says:
August 7, 2010 at 10:35 am
“If we are trying to find out if the rise is natural or man made (or both), then the natural environment can be treated as being a single entity. That is obvious from the form of the mass balance argument. If the natural environment as a whole is a net sink, then it isn’t the cause of the rise, ”
The natural environment cannot be treated as a single entity because it isn’t one. This is one of the things that is fundamentally wrong with the whole mass balance argument: it has many degrees of freedom, not just the one. You cannot legitimately say that the “natural environment as a whole” is the cause of the rise unless you include the whole of the natural environment, including man, who is also part of nature. The natural environment as a whole is not a net carbon sink, because the amount of carbon in the natural environment as a whole is neither increasing nor decreasing (transmutation nof elements excluded). It isn’t even true that the natural environment minus man is a net sink, because man can only add carbon to the natural-environment-minus-man by first removing that carbon from the natural-environment-minus-man. In fact, since the number of humans is increasing, and humans contain carbon, the natural-environment-minus-man is a net source.
You have ignored the specific points I made and repeat below. Please try to think about them:
The “natural environment” is not a single entity doing only one thing at a time. The rise is happening in one part of the environment (the atmosphere); other parts of the environment are removing CO2 from the atmosphere; still others are adding to it. The cause of the rise could be in any or some or all of those parts (of which the anthropogenic part is just one). Look at it yet another way. Humans are part of nature; it would be just as valid (and just as invalid) to lump the anthropogenic emissions in with the “natural environment”, and using the same logic ascribe the rise to tectonic activity, or bacterial decay, or anything else that, singly or in combination, has a sufficient magnitude.
You have also ducked out of answering my question of what you mean by “the CO2 is man made”. Please answer it. Give a clear definition or restatement of that phrase in other words.
Let’s look at the numbers to get a feeling for the most significant factors in atmospheric CO2 levels.
CO2 in air: 2 x 10^15 kg
Change in CO2: 1 x 10^13 kg/yr (.5 %)
Human CO2 production: 3 x 10^13 kg/yr (1.5%)
(http://www.eia.doe.gov/oiaf/ieo/highlights.html)
HCO3 in mixed ocean: 2 x 10^13 kg (1%)
(about 10% of the ocean volume mixes due to action of winds, down to 400m)
Total biomass: 2 x 10^15 kg
(Whittaker, R. H.; Likens, G. E. (1975). “The Biosphere and Man”, in Leith, H. & Whittaker, R. H.: Primary Productivity of the Biosphere. Springer-Verlag, 305-328)
Biomass CO2 equiv: 7 x 10^14 kg (39%)
(if you burned every living thing to CO2)
Which factor do you think dominates? Remember, almost everything uses oxygen and emits CO2 (plants too).
Consider this: In a warmer world, microbes will consume dead vegetation more effectively, converting cellulose and lignin to CO2. The soil exhales CO2. (http://en.wikipedia.org/wiki/Decomposition)
This biological response is consistent with the observations by Siegenthaler and others that CO2 levels in the atmosphere lag temperature change by 800 to 1200 years.
(Siegenthaler, U., Stocker, T., Monnin, E., Luthi, D., Schwander, J., Stauffer, B., Raynaud, D., Barnola, J.-M., Fischer, H., Masson-Delmotte, V. and Jouzel, J. 2005. Stable carbon cycle-climate relationship during the late Pleistocene. Science 310: 1313-1317.)
See also : http://www.co2science.org/articles/V8/N48/EDIT.php
I have dealt with many physicists who think biology is a ‘soft’ science they can trivialize. Biology is a fantastic example of complex thermodynamics in action.
Sorry Paul, the argument I put forward is whether the observed rise is attributable to man or to nature (i.e. everything other than man) or both. That is perfectly straightforward, and a perfectly reasonable question.
The “humans are part of nature” line is transparent sophistry, you are basically saying that the rise is natural even if it is anthropogenic! It has also appeared in just about every discussion of the mass balance argument that I have encountered so far (so it isn’t even original). It usually pops up when it becomes clear to everybody concerned that the natural environment (as a whole) is a net sink and thus it is obvious that anthropogenic emissions are responsible.
Julian Flood, you write:
“Google Emiliania huxleyi for a counter example. This produces calcium carbonate in such quantities that the blooms show up from space as vast milky plumes.”
Exactly, the biosphere is withdrawing CO2 still faster and thats why human emissions is likely to have only temperary effect.
Already now we can see that for same temperature, the CO2 increase per year is falling significantly:
http://wattsupwiththat.com/2008/12/17/the-co2-temperature-link/
In the present discussion i show Ferdinand that pCO2 in oceans has actually stagnated in concentration:
http://hidethedecline.eu/pages/posts/co2-carbon-dioxide-concentration-in-the-oceans-72.php
The above illustration is from AR4 – however, IPCC forgot to tell that pCO2 appears stagnating. The indicator used by IPCC – pCO2 – Ferdinand Engelbeen believes cannot be used to indicate CO2 amount in upper ocean layors.
pH has been constant or a decade too in oceans:
http://hidethedecline.eu/pages/posts/ph-in-oceans-31.php
So with no changes in pH one should expect pCO2 rise if human activity presently had larger impact on CO2 levels than the withdrawel of CO2 that you refer to.
Finaly Engelbeen says that there is a lot of CO2 in the upper layers of the oceans that is not represented by the pCO2. But i this is calcium carbonate sedimenting out of the system, still the human influence is neutralized by natural factors.
My point is not that humans dont add CO2 (of course) but that this human Co2 faster and faster is omitted by nature including a growing biosphere. If human CO2 is still faster assimilated by a growing biosphere, this changes the “problem” claimed as consequence of Co2.
K.R. Frank
– The stagnating pCO2 as indicator of CO2 amount in upper layers of the oceans is important because CO2 concentration is in equilibrium with most CO2-compounds still in the CO2 still in the returning pool of CO2. Carbonates sedimenting out are no longer easily returned to the Co2 pool and to some represents degree “lost” CO2. More sedimenting carbonates means less CO2 despite humans.
Richard S Courtney says:
August 7, 2010 at 8:52 am
I write to provide a clarfication.
At August 7, 2010 at 4:41 am you assert:
“The fast equilibrium is only for the upper ocean layer, which follows the atmospherice increase with about 10% increase in mass for a 100% increase in the atmosphere. The 40 years equilibrium I suppose is for thermal (dis)equilibrium, not for CO2.”
Sorry, but that is incorrect.
Although it is true for a global temperature fluctuation lasting only a few years , it is not true for a long-term global temperature change that happens over decades.
A short term temperature fluctuation (e.g. seasonal or ENSO) only induces CO2 exchange between ocean surface layer and the air. So, the limiting exchange rate is that between air and ocean surface. And (as e.g. your Figure 2 shows) that rate is so fast that it responds to a equilibrium change (induced by a temperature change) almost instantly (i.e. within weeks).
But a long-term temperature rise depletes the CO2 in the ocean surface layer. So, in this case, the limiting exchange rate is between the ocean surface layer and deep ocean. And this exchange rate is very slow so establishing the equilibrium for a long-term temperature rise takes decades.
OK, no problem with a longer response time for sustained temperature changes.
This is merely one example of why your mass balance is wrong. It assumes the amount of CO2 exchanged seasonally between air and ocean surface is a constant, but it is not: the amount varies over decades as CO2 is transferred between the ocean surface layer and deep ocean in response to changing global temperature affecting the equilibrium state of the entire system.
Richard, you are assuming points which never were said or implied: the seasonal changes play only play a role in the total mass balance, if there is an unbalance. If there is an unbalance within one year or over several years, due to any probable cause, that would show up in the residuals at the end of each year. But the residuals, including their variability, were negative over at least the past 50 years. Thus whatever caused the variability in the uptake of CO2, that was not strong enough to make that the natural flows were adding any net amount of CO2 to the atmosphere.
Further the long term influence of temperature on CO2 levels is not more than 8 ppmv/C, hardly noticable in the increase of over 100 ppmv we see nowadays.
Richard S Courtney says:
August 7, 2010 at 9:04 am
I object to you posting personal lies as a bolster to your assertions!
At August 7, 2010 at 5:30 am you say:
“I am waiting several years now for such an alternative explanation by Richard’s companions which doesn’t violate one or more of the observations…”
That is a demonstrable lie! You have had several such examples from me. Indeed, I provided one in my post to this thread at August 6, 2010 at 6:38 am.
Your errors are forgiveable. But your posting a demonstrable lie is not.
Richard, not the big words, please. I was referring to Arthur Rörsch looking for an alternative explanation for the increase in the atmosphere. Until now the solutions fail one or more observations.
The same problem with your examples, if we may look at one:
A change to average ocean surface layer pH of only 0.1 would reduce the ocean sequestration rate by more than is required to achieve the observed rise to atmospheric CO2 concentration.
A general reduction in pH of the oceans indeed would increase pCO2 of the oceans, leading to more outgassing and an increase in CO2 of the atmosphere. But that would violate several observations:
– More outgassing means a reduction of total carbon (DIC) in the upper ocean level, but we see an increase. The average flux is from the atmosphere into the oceans, not reverse.
– The 13C/12C ratio of the oceans (both deep and surface) is much higher than of the atmosphere. Even including the isotope fractionation at the sea-air boundary, that would increase the d13C/12C ratio of the atmosphere, but we see a decrease.
– Last but not least: the mass balance: if ocean outgassing would be the main cause of the increase, then the total increase in the atmosphere would be the sum of the extra outflow plus the human emissions. But the observed increase is less than the human emissions alone.
Thus the possibility of a pH decline as cause of the increase violates three observations. This is sufficient proof to reject that hypothesis.
Richard S Courtney says:
And of course, I knew that… sorry for being unclear.
Ferdinand Engelbeen says:
Actually, your insistence on this astounds me.
How do you know that our CO2 emissions are not completely nullified by some natural process, ie. oceanic uptake or increased plant growth, and it’s not SOME OTHER source that is the cause of the increase?
Honestly, 368 posts are basically all about this question, and you have failed to explain this. Your simple assertion that “it must be so” is the major sticking point here, and to use the word a second time, it is astounding to me that you can’t see it, and that you can’t see how this is circular.
Dikran Marsupial says:
August 7, 2010 at 12:20 pm
“Sorry Paul, the argument I put forward is whether the observed rise is attributable to man or to nature (i.e. everything other than man) or both. That is perfectly straightforward, and a perfectly reasonable question.”
No, it isn’t. This is a false dichotomy. The observed rise may be attributable to something other than man. It cannot be attributable to everything other than man. You are arbitrarily lumping disparate things together while ignoring the simple fact that they could be arbitrarily lumped together in numerous other ways. It is not sophistry to note that the same illogic you use to “prove” that man is the cause could be used to prove that any of the other sources is the cause (singly or in combination). It is not sophistry to note that, in science, man is part of nature; pretending otherwise leads to stupid blunders like this.
And you still haven’t answered my question: what do you mean by “the rise in CO2 is man made”? Do you mean “CO2 levels would not have increased if man had not emitted this CO2”. If not, then what do you mean?
Some musings:
I think I begin to understand the the difficulties that Paul Birch and others have had in accepting the arguments of Ferdinand and Dikran, and whilst I firmly believe that the latter’s conclusion – that human emissions have caused the recent increase in atmospheric CO2 – is correct and is supported by the logic of their arguments, I think there IS an additional silent assumption made in the “mass balance” argument that has been employed, which may be the source of the disagreement.
Let’s go back to Dikran’s 10:48am mass balance equation:
dC = E_anthropogenic + E_natural – U_natural
The other assumption made (besides conservation of mass) , was indeed acknowledged by Dikran with the words “assuming anthropogenic uptake is negligible”, but then it was passed over: I think is the source of the disagreement.
So, let me construct an, albeit rather odd, world where anthropogenic uptake is NOT negligible, indeed where it is much the same in magnitude as anthropogenic emissions. In this odd world, oddhumans don’t get oil and coal out of the ground: they MAKE IT by EXTRACTING CO2 out of the atmosphere and using their chemical wizardry (and plentiful solar energy!) to turn it into oil and coal, which they then burn nostalgically in their antediluvian cars and homes and factories etc, thereby releasing the CO2 in equivalent amounts back into the atmosphere. Yes, I know it’s barmy, but bear with me.
So, in this odd world, U_anthropogenic is close in value (though opposite in sign, of course) to E_anthropogenic (and is known with similar precision) and the mass balance equation can no longer ignore it and therefore becomes:
dC = (E_anthropogenic – U_anthropogenic) + (E_natural – U_natural)
But now, if in this oddworld we observe an increase in atmospheric CO2 and we ask the question, “what is the source of the increase?”, then we haven’t a clue! We know it can’t be oddhumans, because (E_anthropogenic – U_anthropogenic) is close to zero.
I find echoes of that difficulty in the writings of those who do not accept the mass balance argument.
So the moral of this tale is this: the mass balance equation involves TWO assumptions, the conservation of mass and the fact that U_anthropogenic is negligible. But that negligible nature of U_anthropogenic comes about ONLY because we real humans don’t make our coal and oil by extracting CO2 from the air: we get it by digging it up. And we dig it up from deep in the Earth where, until we disturbed it, it had no part in the short/medium term carbon cycle (ie that involving the atmosphere/oceans/biosphere): it was outwith the system and would have remained so substantially for millions of years if we hadn’t disturbed it. And that is the crucial point.
Only humans*, by extracting fossil fuels from the Earth’s crust and ADDING them as CO2 to the short/medium term carbon cycle are causing a NET increase in the amount of carbon in that carbon cycle. Only we are adding to the system and most of our additions from fossil fuels go into the atmosphere first. U_anthropogenic is negligible because we get our carbon out of the ground, not from the short/medium term carbon cycle, and that is why we can look at the mass balance equation and be sure that the rise in atmospheric CO2 is anthropogenic.
[* OK, a bit (less than 1% of human emissions) from volcanoes]
Frank Lansner says:
August 7, 2010 at 10:33 am
Thanks for answer Ferdinand.
What CO2-compound is included in nDIC besides the carbonates that are in equilibrium with Co2? We are talking about upper ocean layers and thus carbonates sedimenting is not in question.
Carbonate sedimentation may be one of the culprits, as mentioned by Julian Flood. But as one sees an increase of DIC (mainly bicarbonate and carbonate), while the pH remains flat, that is a contradiction, as with increasing DIC, one should expect a decrease in pH (as seen in the decade before the last one). That means that something else is working, which neutralises the pH decline. I really have no idea what that can be.
Maybe the deep ocean upwelling changed, bringing more deep ocean waters up to the surface…
The stagnant pCO2 may have as result that the increase of CO2 in the atmosphere is more readily absorbed, as the pCO2 difference air-water increases.
Ferdinand says:
“Further the long term influence of temperature on CO2 levels is not more than 8 ppmv/C, hardly noticable in the increase of over 100 ppmv we see nowadays.”
You are saying there is not positive feedback? If so I agree. Otherwise a 100 ppmv rise in CO2 would caused a very large rise in temperature. You say a rise in temperature causes a rise in CO2. That has not happened. So again, I agree.
And you may be right about the mass balance hypothesis, but it comes across as somewhat of an argumentum ad ignorantiam assumption: since we don’t know all the possible sources and sinks, and we don’t know their magnitude for the most part, it seems you are saying, “Therefore, it must be all due to human emissions.”
Did I overstep by saying “all”? Sorry. That’s just one more unknown variable.
<rant>
The IPCC purports to know exactly how much CO2 is emitted in total. But it is somewhat of a leap to assume that human activity is more responsible than, for example, sea surface temperature.
And even if human activity is the cause of the rise, rather than a warming ocean, there are two relevant points: first, the planet warms and cools despite the rising trace gas, not because of it [except as you note, to a very small degree]. And second, there is no real possibility of convincing India, China, Russia, Brazil, and scores of other countries to tell their citizens to accept subsistence living, after the West has enjoyed the ride up until now. So this is really a pointless argument unless you can provide proof that an increase in CO2 is a demonstrably bad thing. So far, the evidence does not support that argument.
As Prof Richard Lindzen notes:
Which brings to mind the famous Marcus Aurelius quote:
Being interested in the question of temperature related to a tiny trace gas is fine. But too many folks take one step too far, and insanely advocate hobbling the primary basis for our standard of living — fossil fuels — based on extremely sparse knowledge, along with the certainty that no matter what we do or don’t do, CO2 will continue to rise as the planet warms, and 150 other countries refuse to curtail their CO2 emissions. [The Economist reported that China is now building 2 – 4 new coal-fired power plants every week, and intends to continue at that rate at least through 2024. Their population wants electricity, and they will have it from the cheapest source: coal.]
Prof Freeman Dyson also points out our lack of knowledge:
We do not even know what the parameters of the biggest CO2 sinks are, yet many in the ranks of the insane demand crazy solutions based on an almost total lack of knowledge.
So the important question is not whether human activity is the cause of increased atmospheric CO2. That question is academic. The important question is why nefarious people in the West [such as, for one example of many, Maurice Strong — who lives in China] do not utter a word of concern over the fast ramp-up of CO2 by China and many other countries. For our part, the U.S. is not increasing its CO2 emissions. Yet the evil leaders of the ranks of the insane always expect the U.S. and the West to cut our own throats, while giving a free pass to most of the world’s countries.
</rant>
Paul Birch says:
August 7, 2010 at 10:44 am
Indeed, the fine nuances of a different language are not always easy to grasp… Even if one uses the other language over a long time. Second try:
Paul: “1) CO2 levels would not have increased if man had not emitted this CO2.
It doesn’t necessarily imply they would have stayed the same – they could have fallen – but if they would have risen at all then we could only say “part of the CO2 increase is man-made”.”
Definitive answer:
Except for a small increase due to the temperature increase since the LIA, CO2 levels would not have increased if man had not emitted this CO2. Thus near all of the CO2 increase is man-made.
Some detailed background:
Based on the historical ratio: Temperature is the main driver over the past 800,000 years for CO2 levels, with some lag. In this case the LIA – current times warming of maximum 1 C would have increased the CO2 levels with not more than 8 ppmv. Other possibilities of natural causes of part of the increase (volcanic eruptions, ocean pH changes,…) are excluded at least in the past 50 years, as the mass balance excludes any addition from natural sources.
Well, I don’t quite know what you mean by “disagreed on the second part”
That was about the word “part” instead of “all” in the last sentence.
But in that case your mass balance argument is totally invalid as a means of proving it, because there is no way it can answer the question of what would have happened in different circumstances. What would have happened matters – and needs to be proved before you can assign causation.
I don’t see why the mass balance is invalid as a proof in this case: in the current circumstances, there is no room for any natural addition. In different circumstances, the result may be different. If e.g. some supervolcano would emit 5 GtC next year, then the mass balance at the end of the year should show a net increase of 9 GtC in the atmosphere, of which 8 GtC from human emissions and 1 GtC from the volcano in excess of the current average natural sink rate of 4 GtC. In that case nature as a whole is contributing to the increase in the atmosphere.
Paul: “3) CO2 levels have risen by no more than the amount of CO2 man has added to the atmosphere.”
Ferdinand: “No. That is flatly contradicted by the mass balance: CO2 levels have risen less than the amount of CO2 man has added to the atmosphere. And that is what makes that our interpretation of 1) is true.”
Once again, it seems your knowledge of either English or logic is letting you down.
Indeed my misinterpretation… The statement is true and as long as that is the case, there is no net addition from nature as a whole to the increase of the atmosphere.
Ferdinand:
You still do not get it do you?
The total sysem needs to be considered, and not only the net flux.
At August 7, 2010 at 1:43 pm you say:
“A general reduction in pH of the oceans indeed would increase pCO2 of the oceans, leading to more outgassing and an increase in CO2 of the atmosphere. But that would violate several observations:
– More outgassing means a reduction of total carbon (DIC) in the upper ocean level, but we see an increase. The average flux is from the atmosphere into the oceans, not reverse.
–
– The 13C/12C ratio of the oceans (both deep and surface) is much higher than of the atmosphere. Even including the isotope fractionation at the sea-air boundary, that would increase the d13C/12C ratio of the atmosphere, but we see a decrease.
–
– Last but not least: the mass balance: if ocean outgassing would be the main cause of the increase, then the total increase in the atmosphere would be the sum of the extra outflow plus the human emissions. But the observed increase is less than the human emissions alone.
–
Thus the possibility of a pH decline as cause of the increase violates three observations. This is sufficient proof to reject that hypothesis.”
No, no and no!
There is not sufficient data to observe the change in global total carbon in the ocean surface layer with sufficient accuracy for a determination of whether it has increased or decreased over the last 50 years.
The change to isotope fractionation does not match the assumption of an anthropgenic cause (the magnitude of the change differs from that expected from an anthropogenic cause by a factor of at leat 3 x). And the change in the isotope ratio with outgassing from ENSO variations shows that it is not posible to distinguish between ocean outgassing and the anthropogenic emissions. The effect of the pH change would be similar for the postulated pH change or a temperature from ENSO.
And the mass balance argument is complete nonsense when applied to a change to the system. All the mass balance would show is that the system has changed to alter the net flux of CO2 between the air and the rest of the carbon cycle WHICH IS WHAT WE SEE.
As I said, you still do not get it.
The mass balance indicates a change to the system but provides NO indication of any kind as to the cause of the change.
Richard
It would be good to know more about tne methane cycle and its link to the carbon cycle. There is more and more recognition of the existence of “tight gas”, methane trapped in sedimentary rocks. Wherever sedimentary rocks are exposed, eg sea cliffs, plate boundaries, there must be a flow of methane into the sea and atmosphere. This would be oxidised to CO2. Can the size of this flow be estimated?
Richard S. Courtney wrote
“The total sysem needs to be considered, and not only the net flux.”
No, if you aim to determine only if the observed rise is anthropogenic, natural or both, only the net flux is important. The rate at which atmospheric CO2 increases or decreases depends only on the difference between total emissions and total uptake, i.e. the net flux, the total volume of the exchange flux is irrelevant.
To demonstrate that, say total emissions were 10 GtC per year and total uptake were 9 GtC per year; obviously atmospheric CO2 would increase by 1 GtC per year. Now consider a situation where total emissions were 1000 GtC per year and total uptake were 999 GtC per year; atmospheric CO2 would still only rise by 1 GTC per year, even though the volume of the exchange flux is two orders of magnitude higher. It is only the net flux (1 GtC per year in both cases) that controls the rise.
Slioch: Yes, you could say that it was an assumption that anthropogenic upatke is negligible, so I’d happily concede that point. However, as you indicate anthropogenic uptake would need to reach half of anthropogenic emissions before it had any effect on the outcome. A pretty reasonable assumption!
You can also be 100% sure that any anthropogenic uptake will be recorded in great detail, because people will be selling it for those carbon credit things (note any re-forestation will already be implicitly included in land use change).