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!
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Richard S Courtney says:
August 6, 2010 at 2:51 pm
Your argument certainly is, as you say, “simple math”. Indeed, it is so “simple” that it is wrong because it makes false assumptions then calculates the results of those assumptions.
There are no false assumptions in my math. The math is simply the sum of what is known and unknown in the mass balance. The result of what is known is that the sum of the unknowns is negative over the past 50 years. That is basic math and nothing else.
Do I really need to yet again explain why your assumptions are plain wrong?
Please read what I have repeatedly written – in as many ways as I could – above.
You may believe that something else than the emissions could be blamed for the increase. That is up to you, but that is completely baseless if nature as a whole acts as a sink for CO2.
“If the “the addition of man-made CO2” were directly responsible for the “the increase in total mass” then these two parameters would directly relate, but they do not. As I have repeatedly said (e.g. above at August 6, 2010 at 6:38 am):
“in some years almost the entire anthropogenic emission seems to be sequestered and in other years almost none of it”.
You responded tothat with a load of arm waving about “signal-to-noise ratio” that is pure twaddle.
If you find that the signal to noise ratio doesn’t play a role at all, that only proves that you have no background knowledge in these matters. If two variables influence a third one, independent of each other, then the influence where one is interested in may be weak, because the other variable interferes. In this case, temperature variations have a short term, but important influence on the rate of increase. Human emissions too have a weak influence on the rate of increase (but a strong one on the trend itself), but that is only certain after 2-3 years of trend.
Your mass balance calculations assume the residual is induced by the anthropogenic emission, so – if that is the case – then please explain why in some years almost the entire anthropogenic emission seems to be sequestered and in other years almost none of it.
My mass balance assumes nothing. It only shows that there is a negative residual from the seasonal changes. The negative residual varies, as can be seen as the green part of Fig 3. That is mainly caused by temperature variations, which influence the sink rate of oceans and vegetation.
Is the trend directly related to the emissions? That is what you need to prove, not assert.
Here is the correlation between emissions and increase in the atmosphere:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
If you know of any natural process that independently follows the emissions with such an incredible accurate trend (R^2: 0.9966) I want to see that.
And is the derivative of the trend mainly influenced by temperature? If so, then why is the trend not mainly influenced by the temperature?
Because most of the temperature variability is short term and levels out in a few years time. The long term temperature trend is small and near absent in the past decade.
Slioch says:
August 6, 2010 at 3:22 pm
Thanks for the addition. But as far as I know, volcano emissions (except in extreme periods) and outgassing are included as part of the natural cycle, together with other sources like carbonate rock weathering. At the other side, more permanent carbon storage on land from vegetation (peat, browncoal, coal) and in the oceans (calcite deposits) removes carbon from the cycle…
CO2 residence time is 5 to 15 years.
Dr. Robert H. Essenhigh (2009), Professor of Energy Conversion at The Ohio State University
Essenhigh, R.E. 2009: Potential dependence of global warming on the residence time (RT) in the atmosphere of anthropogenically sourced carbon dioxide. Energy & Fuels 23: 2773-2784.
(http://jennifermarohasy.com/blog/2009/04/carbon-dioxide-in-atmosphere-5-15-years-only/).
“The data source used was outcome of the injection of excess 14CO2 into the atmosphere during the A-bomb tests in the 1950’s/60’s which generated an initial increase of approximately 1000% above the normal value, and which then declined substantially exponentially with time, with [RT]= 16 years.”
12CO2 has a shorter residence time, about 5 years.
“The long-term (~100-year) rising atmospheric CO2 concentration is not from anthropogenic sources but, in accordance with conclusions from other studies, is most probably the outcome of the rising atmospheric temperature which is due to other natural factors. This further supports the conclusion that global warming is not anthropogenically driven as outcome of combustion. The economic and political significance of that conclusion will be self-evident.”
Also: Tom V. Segalstad
Associate Professor of Resource and Environmental Geology
The University of Oslo, Norway
Volume 12, Number 31: 5 August 2009
“The correct evaluation of the CO2 residence time — giving values of about 5 years for the bulk of the atmospheric CO2 molecules, as per Essenhigh’s (2009) reasoning and numerous measurements with different methods — tells us that the real world’s CO2 is part of a dynamic (i.e. non-static) system, where about one fifth of the atmospheric CO2 pool is exchanged every year between different sources and sinks, due to relatively fast equilibria and temperature-dependent CO2 partitioning governed by the chemical Henry’s Law (Segalstad 1992; Segalstad, 1996; Segalstad, 1998).”
Ferdinand Engelbeen says:
August 6, 2010 at 12:29 pm
quote
Julian, we don’t need to know the flows: as long as the increase in the atmosphere is less than the emissions, the emissions are fully responsible for the increase… No need to tackle other parts of the carbon cycle, except for better understanding of what happens in nature.
unquote
That would only be true if nothing else was varying. All the flows are varying for various reasons, some natural, some anthropogenic. Sinks are changing as well as sources. With 18 variables then I don’t see how you are able to say anything about attribution.
You keep saying, in effect, that the CO2 cycle can be treated just as a big box and that a change in input will automatically be reflected in the output. I do not see this as a logical argument. If the sinks are varying as well as the sources then back-calculating what caused what is not possible. What comes out is a reflection of all the variations, not just the variation in input. Yes, the new input will have an effect on the output but what it is, its proportion of the whole mass of effects, will also depend on the internal changes in the CO2 black box.
Imagine a lake with eighteen streams pouring into it controlled by valves with changing settings depending on temperature, business cycles, agriculture, deforestation, acid rain details from thirty years ago, while down at one end a little boy widdles into it. From it runs a series of pipes of varying diameter with valves which also change according to the season, the orbit of the planet, the amount of oil spilled on the lake surface by a passing Benjamin Franklin, how windy it is, whether the ducks are being fed too much bread, etc etc etc .
You know the bladder capacity of the little boy and the level of the lake. The level of the lake rises by an amount weakly correlated with the boy’s bladder capacity. Why is the lake level changing?
But I’m willing to learn. Perhaps if you follow through your logic very slowly and carefully, explaining how you know that the 4 Gt is not the residue of much larger, mostly sequestered, changes, then I’ll catch on. Don’t forget to allow for changing sinks.
Tell you what. Let’s see if any of the posters/lurkers on this thread can run up a simple model. A central reservoir fed and emptied by varying ducts should produce some answers which might clarify thought processes, not least mine. Perhaps the Treasury could fire up their hydraulic computer and model it on there — it’s just the right sort of problem.
JF
Mosher, re your request for a reduction in output from an increase in input — Google Chaotic Lorenz Water Wheel . In a sufficiently complex system nothing would surprise me.
Ferdinand Engelbeen, Dikran Marsupial, and Slioch: your posts are painful to read, they are so riddled with logical error. This is not algebra, it is calculus. In a feedback system, the feedback opposes change. Thus, when an external input pushes in one direction, the feedbacks pushing in that direction automatically relax to maintain the equilibrium. Your statements to the effect that the abstract accumulation of the anthropogenic input is greater than the overall rise prooves that the rise is anthropogenic are… how can I put this kindly… mindless. This is what feedback systems do.
Let’s consider a simple feedback system, that of your household thermostat. It is a modern thermostat which has the ability to maintain different temperatures in the day when nobody is at home and at night when somebody is. It’s summertime and somebody has set the thermostat to maintain 74 degF during the day, and 69 degF in the evening.
One evening, you find you are cold, so you bring out a space heater and turn it on full blast. Yet, the house stubbornly stays 69 degF. You go to sleep, and you wake up late to find the house is 74 degF. You calculate the heat put out by your little space heater, and determine that it has put out enough heat that the house should be 79 degF. Still, you conclude that the house has warmed because of your little space heater, because it is warmer, and the space heater put out heat, QED.
This is the situation here. The Earth’s carbon regulator doesn’t care about your little “space heater”. It’s running on its own program. And, your logic is akin to that of a witch doctor who … oh never mind.
Thank you Dr Engelbeem, for this article and for the tireless and polite way you have fielded questions, even some of the difficult ones.
That said, I was disappointed with this presentation.
Maybe I’ve been spoiled by the amount of effort other contributors like Steve Goddard, Willis Essenbach, and Bob Tisdale put into their presentations, always trying to use the latest data and making up their own graphs and images to illustrate their conclusions, yet here we have a presentation on one of the central planks of the AGW conjecture and all we get is a ten year old graph with out of date figures in it and the bald assertion (or should that be hunch) that because man is putting up 7GT of CO2 and 4GT are staying up, only man can be adding CO2 to the atmosphere. In a complex and chaotic system like the biosphere, this is simplistic in the extreme.
The updated figures from New Scientist are 120GT for Land, 90GT for Oceans, and 7.2 GT for man, but I’ve seen different figures in other comments here, which could be even more up to date, and that begs the question, do we even know definitively how much CO2 is going up from the various sources.
No account has been taken of the sequestration of CO2 by mans actions through agriculture and forestry, for instance. Even the act of dumping our rubbish in the ground and filling it over could be said to be “fixing” CO2 . If all that amounted to 4GT of carbon sequestrated, that would put a completely different complexion on the figures you present here.
It completely ignores the elephants in the room, the tens of thousands of active volcanoes, and the millions of meteorites that rain down on the Earth each day. Both of these are unique in the sense that they are the only source of new CO2 into the biosphere, whereas Land, Oceans and man are just recycling CO2 already within. So far, all I’ve seen is guesses as to the contribution of CO2 from these sources.
They are also unique in the sense that they do not sequester CO2 in any way, yet we are asked to accept that the biosphere can handle the sequestration of this extra “new” CO2, but it chokes on the CO2 recycled within it by man.
I don’t deny that man is contributing to the rise in CO2 into the atmosphere, and I’ll hope that the next presentations further enlighten me, but on the basis of this one, I’m not encouraged.
Thank you again,
Paul Hanlon.
re: Dikran Marsupial says:
August 6, 2010 at 4:11 pm
and Ferdinand Engelbeen says:
August 6, 2010 at 4:47 pm
Yes, having slept on it, I think you are right. Atmospheric CO2 has been on a generally downward trend for the last few tens of millions of years, which suggests that the long term sequestration of carbon (via subduction of carbonates, for example) is more than able to compensate for the CO2 emitted by volcanoes. There is no reason to believe that this process does not continue into the present and that therefore the modest contribution of volcanoes continues to be sequestrated as part of the very long-term carbon cycle. In order for volcanic activity to be recognised as a net contributor to atmospheric CO2 one would need to demonstrate that there had been a recent large increase, greatly more than the long-term average, in volcanic CO2 emissions (or a cessation of sequestration) : and that is certainly not the case.
I think I’ve just provided myself with a falsification of the ancient proposition: in vino veritas!
Ferdinand:
This is becoming tiresome. You repeatedly attempt to excuse your errors by adding additional assertions. Now, at August 6, 2010 at 4:41 pm, you say:
“If you find that the signal to noise ratio doesn’t play a role at all, that only proves that you have no background knowledge in these matters. If two variables influence a third one, independent of each other, then the influence where one is interested in may be weak, because the other variable interferes. In this case, temperature variations have a short term, but important influence on the rate of increase. Human emissions too have a weak influence on the rate of increase (but a strong one on the trend itself), but that is only certain after 2-3 years of trend.”
Say what!? “temperature variations have a short term, but important influence on the rate of increase”? Have you never heard of Henry’s Law?
Global temperature is aserted to have increased over the last century. There is an exchange rate between ocean and air. Can you prove that the exchange rate provides equilibrium in less than (as you assert) 2-3 years? It is generally assumed that the rate would require about 40 years for equilibrium. Indeed, your own Figure 2 denies such a rapid adjustment to equilibrium as you suggest.
It is not science to make assumptions that provide circular arguments justified by assertions that have no basis in demonstrated reality.
Richard
Joseph Day says:
August 6, 2010 at 7:43 pm
CO2 residence time is 5 to 15 years.
True, but irrelevant here and irrelevant for any amount of CO2 in excess: the decay time for excess CO2 is around 40 years, based on the sink rates of currently 4 GtC/year, while the exchange rates of about 150 GtC/year are responsible for the residence time of about 5 years. The residence time doesn’t change the total amount of CO2 in the atmosphere, but influences its isotopic composition.
Julian Flood says:
August 6, 2010 at 8:23 pm
That would only be true if nothing else was varying. All the flows are varying for various reasons, some natural, some anthropogenic. Sinks are changing as well as sources. With 18 variables then I don’t see how you are able to say anything about attribution.
We only have rough estimates for what happens in nature, but even then, we know the exact net result of all the changes of the 18 (or more) variables, both on inputs and outputs, over a year: that is the difference between what is emitted and the increase in the atmosphere. That is what the law of conservation of mass dictates. That is visible as the net sink rate, the green part of Fig. 3 of the introduction. In all years over the past 50 years, there is no net addition by nature, only a net removal of CO2 out of the atmosphere. Regardless how large the many inputs and outputs were or how they changed over the year(s). That makes that the human emissions are the sole cause of the increase of CO2 in the atmosphere.
The graph shows that the net sink rate is variable, but quite moderate: +/- 1 ppmv (2 GtC) from year to year. Mainly the result of temperature changes at around 4 ppmv/C. That the changes are quite moderate may have to do with the opposite effect of temperature on oceans and vegetation. The variability is not more than halve the emissions.
You keep saying, in effect, that the CO2 cycle can be treated just as a big box and that a change in input will automatically be reflected in the output. I do not see this as a logical argument. If the sinks are varying as well as the sources then back-calculating what caused what is not possible. What comes out is a reflection of all the variations, not just the variation in input. Yes, the new input will have an effect on the output but what it is, its proportion of the whole mass of effects, will also depend on the internal changes in the CO2 black box.
It is good practice to use a “black box” model if you have a lot of influences with unknown proportions and then look at the behaviour of the model. In this case the behaviour of the whole CO2 cycle is surprisingly linear for temperature changes (Vostok and other ice cores) and surprisingly linear for human emissions (45% uptake over the past 100 years). But that is for one of the next parts.
But I’m willing to learn. Perhaps if you follow through your logic very slowly and carefully, explaining how you know that the 4 Gt is not the residue of much larger, mostly sequestered, changes, then I’ll catch on. Don’t forget to allow for changing sinks.
Thanks. I don’t know exactly in how far the variability of the sink rate is caused by less or more oceanic outgassing and more or less uptake by vegetation. There are a few studies which show that the short term response to temperature changes is mainly a response by vegetation, while the long term response is mainly from the oceans. For the net effect, that is not really important, as in all years over the past half century, nature acted as a net sink…
Bart says:
August 6, 2010 at 8:31 pm
Ferdinand Engelbeen, Dikran Marsupial, and Slioch: your posts are painful to read, they are so riddled with logical error. This is not algebra, it is calculus. In a feedback system, the feedback opposes change. Thus, when an external input pushes in one direction, the feedbacks pushing in that direction automatically relax to maintain the equilibrium. Your statements to the effect that the abstract accumulation of the anthropogenic input is greater than the overall rise prooves that the rise is anthropogenic are… how can I put this kindly… mindless. This is what feedback systems do.
Agreed that the CO2 cycle acts as a system in equilibrium, disturbed by either temperature and/or the emissions. That is in fact the whole point. The response of the system is to reduce the impact of the disturbance: in this case the emissions increase the CO2 level in the atmosphere, decreasing the oceanic outgassing near the equator and increasing the uptake at the poles. That results in a sequestering of about 4 GtC/yr of the 8 GtC/yr emitted (partly in the oceans, partly in vegetation). Still the difference is 4 GtC/yr which shows up as increase in the atmosphere. In this case, the reaction of the system is less than the disturbance, mainly due to the slow uptake speed of the oceans. Thus anyway, the response of the whole natural cycle is an extra uptake, not a release, which shows that the emissions are the sole source of the increase in the atmosphere.
Joseph Day
Regarding Essenhigh (2009), the calculation of the residence time in that paper is fine, however it is also completely uncontraversial, the same result is given in IPCC reports. However Essenhigh is incorrect to say that a residence time of 5 years means that the rise cannot be of anthropogenic origin, becuase he fails to grasp the difference between residence time (the average time an individual molecule stays in the atmosphere – about 4 years) and adjustment time (the amount of time it takes for atmospheric CO2 to adjust to a change in the sources or sinks in the carbon cycle – 70+ years depending on the exact form of the model used to estimate it).
The adjustment time is what controls the rise and fall of atmospheric CO2, not the residence time. The reason is that the large seasonal fluxes constantly exchange carbon between the different reservoirs, however just swapping carbon molecules from one reservoir to another doesn’t change the total amount of carbon in each reservoir. The exchange fluxes are very large, so the residence time is short.
The rise and fall of atmospheric CO2 however depends only on the difference between total emissions and total uptake. This is much smaller than the magnitude of the fluxes, which is why the adjustment time is much longer.
Again this is very clearly explained on Ferdinands web page, and IIRC Ferdinand also explained the flaw in the reasoning in the comments on the blog article you mentioned.
Dear Anthony,
you wrote: “I don’t think Beck’s work is worth much in the context of trends because many of the historical samples he cites were done by less accurate chemical reduction methods and taken in cities with little or no quality control from point to point or metadata.”
That´s not true! This is Ferdinands propaganda.
I do not use data from cities and the chemical methods are well known in every analytical textbook and very accurate (0.33-3%). August Krogh and Otto Warburg had received their Nobel awards using these methods.
Please check the sources on my website.
Well, here’s the thing. I’ve read everything on this thread, and in spite of the fact that I am being ignored, I still come away with the feeling that this is 100% wrong.
I don’t like circular logic, just as I never liked when my parents said “because I said so”. There is nothing here that is anything BUT circular logic. The idea that “the mechanism doesn’t matter, only the results do” is wrong.
In all seriousness, I expected this post to be a rationalization of the method used to determine that CO2 increase is man made, and I was willing to listen. Instead I find that it is nothing of the sort. If this is the definition of a basic tenet of AGW theory, then this post has, to me, confirmed the error of AGW theory.
It has not been proved that human activity is responsible for increasing CO2 levels. It has not been shown that the 285ppm “preindustrial” level is even accurate. There is nothing to demonstrate a credible argument against CO2 rise being the RESULT as opposed to the cause of recent warming, if they are even related at all.
Perhaps this would work in an educational environment where the student is expected to take your word for it and regurgitate the data in a test later, however that is not why I’m here. I was fully willing to read and ponder a credible explanation, instead I get something that is childishly inaccurate.
The underlying assumption that sinks are relatively stable is wrong. The stated assumption that any leftover accounting is anthropogenic is wrong, and the stated assumption that it is possible to accurately account for sources and sinks with current technology is doubly wrong. Maybe after a few years of data from orbital CO2 observation platforms we can begin to have an accurate assessment of CO2 sources and sinks, but not today.
If this was a debate, clearly it was won by Richard S Courtney, although it was obviously not a debate. In fact, I’d like to see a guest post by Mr. Courtney explaining why CO2 increase is NOT man made. Any chance of that?
Julian Flood
“You keep saying, in effect, that the CO2 cycle can be treated just as a big box and that a change in input will automatically be reflected in the output. I do not see this as a logical argument.”
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.
It is true that in the real world, a change in input will cause a change in output. This is because it is a dynamical system (that has been in approximate equilibrium for thousands of years prior to the industrial) if you peturb it with anthropogenic CO2 emissions then the system will respond in an attempt to restore the equilibrium. HOWEVER that is NOT part of the mass balance argument, which just estimates the net environmental flux from observations of the annual rise in CO2 and anthropogenic emissions, assuming only conservation of mass.
“If the sinks are varying as well as the sources then back-calculating what caused what is not possible. What comes out is a reflection of all the variations, not just the variation in input. Yes, the new input will have an effect on the output but what it is, its proportion of the whole mass of effects, will also depend on the internal changes in the CO2 black box.”
The mass balance argument only attempts to determine the net effect of the natural environment on atmospheric CO2. It does not attempt to back calculate what happened to individual sources or sinks, and it is not necessary to do so. All you need to show that the rise is of anthropogenic origin is to show that natural uptake exceeds natural emissions – which is a very straightforward bit of accounting.
“Imagine a lake with eighteen streams pouring into it controlled by valves with changing settings depending on temperature, business cycles, agriculture, deforestation, acid rain details from thirty years ago, while down at one end a little boy widdles into it. From it runs a series of pipes of varying diameter with valves which also change according to the season, the orbit of the planet, the amount of oil spilled on the lake surface by a passing Benjamin Franklin, how windy it is, whether the ducks are being fed too much bread, etc etc etc .
You know the bladder capacity of the little boy and the level of the lake. The level of the lake rises by an amount weakly correlated with the boy’s bladder capacity. Why is the lake level changing?”
Firstly, the mass balance argument is not based on a correlation, but on the rise being consistently less than anthropogenic emissions. The correlation may look weak because of the year-to-year variability, but that variability is never strong enough for the rise to exceed anthropogenic emissions at any point in the last fifty years, and so has absolutely no effect on the mass balance argument.
If you know that the rise was smaller than the amount the boy peed into the lake then you know that the net effect of everything other than the boy was to lower the level of water in the lake. You don’t need to know what happened to the 18 streams, or the other sources or sinks to know that. Again, the only assumption is that water is not spontaneously created or destroyed (conservation of mass) and must be accounted for. This gives:
[rise] = [boys pee] + [net effect of eveything else]
[rise] and [boys pee] are both measured, so we can infer [net effect of everything else] using:
[net effect of everything else] = [rise] – [boys pee]
If [net effect of everything else] is negative (i.e. [everything else] is a net sink) then the only explanation for the rise is the boys pee. That is the mass balance argument. It makes no assumptions about equilibria or changes in sources or sinks – it is equally valid whether they are changing or not – it is just inferring the net behaviour of the environment from quantities we can measure using one assumption and one assumption only – conservation of mass.
Hope that helps – I think the discussion has been derailed by assertions that mass balance makes assumptions that are invalid, however they are not assumptions actually made by the mass balance argument. There is only one, namely conservation of mass.
Also the mass balance argument does not try to infer the behaviour of individual sources or sinks, only the net environmental flux. You only need to know the net environmental flux to determine whether the rise is anthropogenic or natural. If the net environmental flux is negative (i.e. it is a net sink) it can’t be the cause of the rise as it is opposing the rise by taking more carbon out of the atmosphere than it puts in. We know the net environmental flux is negative as the observed rise is less than anthropogenic emissions (see fig. 3) and the difference must be absorbed by the environment – it has to go somewhere. It is as simple as that.
paulhan says:
August 6, 2010 at 8:44 pm
Thank you Dr Engelbeem, for this article and for the tireless and polite way you have fielded questions, even some of the difficult ones.
That said, I was disappointed with this presentation.
Maybe I’ve been spoiled by the amount of effort other contributors like Steve Goddard, Willis Essenbach, and Bob Tisdale put into their presentations, always trying to use the latest data and making up their own graphs and images to illustrate their conclusions, yet here we have a presentation on one of the central planks of the AGW conjecture and all we get is a ten year old graph with out of date figures in it and the bald assertion (or should that be hunch) that because man is putting up 7GT of CO2 and 4GT are staying up, only man can be adding CO2 to the atmosphere. In a complex and chaotic system like the biosphere, this is simplistic in the extreme.
Thanks for the comment, I am no Dr (have a B.Sc. in chemistry, but changed the process control job for a M.Sc. job in process automation many years ago, now retired).
The fact that we have over 300 responses now, shows that there still is a lot of controversy. The ten year old NASA graph is in fact not very important and indeed need an update, but it does show the main storages of carbon and a rough indication of the exchanges between the different compartiments. What is important is graph 3, where the emissions, the increase in the atmosphere and the natural sink rate are plotted. That shows that the sum of all natural in and outflows of the atmosphere is negative over the past 50 years. Whatever the height or the changes of the individual flows over the year(s). Thus the mass balance shows that nature is not responsible for the increase in any way: it is a net sink, not a source of CO2 in the atmosphere.
It may seem simplistic, but as long as the observed increase is less than the human additions, there is no net contribution from the natural CO2 cycle and the human additions are the sole cause of the increase.
No account has been taken of the sequestration of CO2 by mans actions through agriculture and forestry, for instance. Even the act of dumping our rubbish in the ground and filling it over could be said to be “fixing” CO2 . If all that amounted to 4GT of carbon sequestrated, that would put a completely different complexion on the figures you present here.
I haven’t included land use changes, as these are quite uncertain. That accounts for about 20% more CO2 emissions than from burning fossil fuels.
I didn’t look up for all possible human induced sequestering in detail, but here my impression:
Sequestering rubbish is a very small player: all plastics worldwide present about 4% of oil resources (and burying it prevents emissions), natural materials (wood, paper,…) may represent larger quantities, but still pale against fossil fuel use, probably even against land use changes, with or without reforestration. Agriculture in general is a break-even operation: what is sequestered in one month/year is eaten/decaying in the next months/years, except for a slight increase in more permanent humus and root systems, as far as no forests were destroyed first.
As mentioned before, active volcanoes present about 1% of the human emissions and are part of the natural cycle. I have no idea how much CO2 meteorites add to the atmosphere, but I doubt that it is substantial. And that too is part of the natural cycle. As long as there is no enormous increase in volcanic activity or meteorite impact, that plays no role at all in the CO2 levels. Indeed nature could cope with all natural changes: CO2 levels decreased over the past tens of millions of years to the pre-industrial, temperature driven equilibrium. But nature can’t cope with the rapidity of the current emissions, as the mass balance shows…
BTW, the New Scientist page uses Gt CO2, NASA and most others use Gt C, as that isn’t influenced by CO2 transitions into other molecules.
Just to clarify:
(i) the mass balance argument tells us that the environment has been a net sink, but it does not explain why, nor does it attempt to. It is based on two sources of data (anthropogenic emissions and measurements of the observed rise in atmospheric CO2) and one assumtion and one assumption only, namely conservation of mass (hence the name “mass balance argument”).
(ii) The discussion of equilibria etc. is an attempt to explain why the natural environment is a net sink, and is independent of the mass balance argument.
(iii) The validity of any assumptions about equilibria, or what individual sources or sinks are doing has no effect on the validity of the mass balance argument, as the mass balance argument does not depend any such assumptions.
Richard S Courtney says:
August 6, 2010 at 11:43 pm
This is becoming tiresome. You repeatedly attempt to excuse your errors by adding additional assertions. Now, at August 6, 2010 at 4:41 pm, you say:
That is your opinion, not based on any scientific evidence…
“If you find that the signal to noise ratio doesn’t play a role at all, that only proves that you have no background knowledge in these matters. If two variables influence a third one, independent of each other, then the influence where one is interested in may be weak, because the other variable interferes. In this case, temperature variations have a short term, but important influence on the rate of increase. Human emissions too have a weak influence on the rate of increase (but a strong one on the trend itself), but that is only certain after 2-3 years of trend.”
Say what!? “temperature variations have a short term, but important influence on the rate of increase”? Have you never heard of Henry’s Law?
We are talking about the rate of increase, not the effect of temperature on the increase itself. The first year after a temperature increase will show a huge decrease in increase rate (at about 4 ppmv/C), the next year that will be near zero, if there is no temperature change at all. This includes the direct effect of such a change on the equilibrium itself.
A numeric example: A sudden increase of 1 C, due to a super El Niño. First year change in increase rate: +4 ppmv, which means that near all 8 GtC of the emissions remain in the atmosphere or an increase of 4 ppmv. Second year change in increase rate: 0 ppmv (as the temperature remains high), 4 GtC remaining in the atmosphere, CO2 increase 2 ppmv. Third year, a small cooling – 0.5 C. Change in increase rate
-2 ppmv, 0 GtC or 0 ppmv remaining in the atmosphere…
The effect of a prolonged temperature change on the CO2 equilibrium is about 8 ppmv/C on long term. The average increase rate in the atmosphere is 2 ppmv/year, thus even a sudden and prolonged increase of 1 C will be surpassed by 4 years of emissions.
Global temperature is aserted to have increased over the last century. There is an exchange rate between ocean and air. Can you prove that the exchange rate provides equilibrium in less than (as you assert) 2-3 years? It is generally assumed that the rate would require about 40 years for equilibrium. Indeed, your own Figure 2 denies such a rapid adjustment to equilibrium as you suggest.
The 2-3 years equilibrium speed between ocean surface and atmosphere comes from Oeschger e.a., but Takahashi doesn’t find such a lag. See:
http://dge.stanford.edu/SCOPE/SCOPE_16/SCOPE_16_1.5.06_Sundquist_259-269.pdf
The seasonal variability of Fig.2 is caused by vegetation changes. These are very rapid and massive in the NH, giving faster changes in CO2 level than the ocean surface can cope with.
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.
It is not science to make assumptions that provide circular arguments justified by assertions that have no basis in demonstrated reality.
There is nothing circular in these arguments, neither in the mass balance equation. Everything based on the observations.
An error in my previous message:
The first year after a temperature increase will show a huge decrease in increase rate
That must be a huge increase in increase rate…
Seems that I wasn’t alert enough today:
which means that near all 8 GtC of the emissions remain in the atmosphere or an increase of 4 ppmv.
But as the effect of a sudden increase of 1 C is about 4 ppmv and the average increase in CO2 without temperature changes is 2 ppmv/year, the total increase is 6 ppmv, or 12 GtC, that is more than the human emissions. The law of conservation of mass still holds: the increase in the atmosphere in that case is the sum of the emissions + 4 GtC extra from the sudden warming.
Ferdinand Engelbeen says:
August 6, 2010 at 2:37 pm
Paul Birch says: “Anyone who has ever dealt with control systems, filters, transmission lines, feedback circuits or the like will know that what I say is true. Without a detailed understanding of the properties of the whole system, one cannot be sure that weird things like this won’t happen.”
Ferdinand says: “In my former working life it happened that I was a process automation engineer. Thus I may say that I have some experience. Still, even in the most weird non-linear system, if the instantaneous equilibrium is above the instantaneous level, there would be instantly switching from any sink rate to a source rate. Except if you have a different definition of equilibrium?”
By instantaneous equilibrium level I mean the steady state level that would obtain if conditions (such as surface temperatures) stayed constant at their current values. This may not be totally well-defined, since oscillations in the conditions may be part of the conditions, and one would then have to specify exactly what one is holding constant.
Allow me to describe two simple models in which such behaviour is manifest:
Take a U-tube and fill with water. The water level is the same in both arms; this is the equilibrium level. Now jiggle the U-tube. The water level oscillates; as one arm goes up the other goes down. Half the time the level in the righthand arm is below equilibrium. Stop the jiggling for a moment. Near the top of the tube, add narrow side pieces through which water can enter and leave the tube. On the right hand side, make it an adjustable constant flow source (such as a cistern of water at high level); this is the equivalent of our anthropogenic emissions. On the left hand side, leave it open, so that the water spilling through it runs away; this is analogous to the “permanent” deep sinks. The true equilibrium level is now the level of the overflow. The actual steady state level will be somewhat higher, and will depend on the rate at which water is added at the source (it also depends on the diameter of the overflow). Now start the jiggling again. The water level oscillates again as the water sloshes from arm to arm and back again. The average level in the right hand tube is still higher than the equilibrium level, and slightly above the previous steady state (because overflow rates scale as the square root of the head) . However, half of the time the level is less than this; and, if the oscillation is sufficiently strong, for some fraction of the time it will be below the equilibrium level even though the input flow is still continuing, and the right hand arm is still acting as a sink!
If you’ve followed that, let’s look at an even more interesting arrangement in which the level in the input arm is persistently below the equilibrium level. Lengthen the bottom of the U into a horizontal pipe, then add a third arm in the centre (making a squared off W). The equilibrium level is of course the same in all three arms. Shift the input to the middle arm. Start jiggling. Now, as the water sloshes back and forth, the venturi effect sucks water down out of the middle arm, pulling it below the equilibrium level. Even though “anthropogenic” water (cue the toilet jokes) is added in the middle arm, which continues to act as a sink for it, the level in that arm (aka the atmosphere) can remain below its equilibrium level indefinitely.
Now, I’m not saying that the real world CO2 “equilibrium” is like either of those models (I think it much more likely that CO2 sources do keep the atmospheric concentration somewhat above the equilibrium level, at least for most of the time); but in principle, it could be. One cannot rule it out by appeal to the mass balance, or some nonexistent pre-industrial constancy.
“But it happens that the whole CO2 cycle behaves as a simple, quite linear system for temperature changes, despite that a lot of underlying processes are far from linear.”
This is an extremely bold assumption. One that both the historical records and the known physics show to be quite unlikely. Temperature dependences of solubility and chemical equilibria are typically exponential. Absorption by reservoirs is quadratic (because reservoirs integrate rates). Weather is violently chaotic. And so forth. How important the nonlinearities may be is an open question; it cannot simply be hand-waved away.
Thank you for the reply.
I also mentioned forestry.
As for the volcanoes, I can only assume you are referring to Gerlath et al, a paper written in 1992. We hear that when Eyjafjallajokull was active, it was pumping 200-300,000tons of CO2 into the atmosphere daily, a rate of 50megatons per year. Kind of puts the 80-200megatons indicated in that paper into perspective, i.e. most likely wrong.
I would have thought we would have quantified this a lot better, before making the assertion that it is all man’s fault, as these sources have a direct effect on the Mass Balance Equation.
As for the New Scientist, I know they use what I call the scary figures, but I made the conversion into GTC before posting my comment.
440GTCO2 = 120GTC
330GTCO2 = 90GTC
26.4GTCO2 = 7.2GTC
CodeTech says:
August 7, 2010 at 2:31 am
I don’t like circular logic, just as I never liked when my parents said “because I said so”. There is nothing here that is anything BUT circular logic. The idea that “the mechanism doesn’t matter, only the results do” is wrong.
The results, only based on the assumption of the conservation of mass, show that, whatever the underlying mechanisms, nature is a net sink for CO2. That makes that the increase is fully attributable to the emissions. Nothing circular here.
In all seriousness, I expected this post to be a rationalization of the method used to determine that CO2 increase is man made, and I was willing to listen. Instead I find that it is nothing of the sort. If this is the definition of a basic tenet of AGW theory, then this post has, to me, confirmed the error of AGW theory.
The law of conservation of mass is one of the fundaments of chemistry. Any alternative explanation of the increase in CO2 of the atmosphere will violate this law.
If this was a debate, clearly it was won by Richard S Courtney, although it was obviously not a debate. In fact, I’d like to see a guest post by Mr. Courtney explaining why CO2 increase is NOT man made. Any chance of that?
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…
Paul Hanlon: Volcanic emission do indeed have an effect on the mass balance equation
dC = E_anthropogenic + E_natural – U_natural
volcanic emissions are part of E_natural, and so are properly included in the argument.
As to Eyjafjallajokull, if it is producing 50 megatons of carbon per year (assuming that figure is correct, I am happy to take your word for it), the if anthropogenic emissions are 5.5 gigatons of carbon per year (and that is the rather dated figure from Fig 1), then it is prducing only a tiny fraction (less than 1%) of the amount of carbon that anthropogenic emissions are, which is why volcanic emissions don’t leave a visible blip in the annual increase in atmospheric CO2. How many volcanos the size of Eyjafjallajokull erupt every year? Not many, which is why volcanos are not a big player. If you have a reference that gives higher estimates, then I’d be keen to read it.
by the way, if the figure for Eyjafjallajokull is 50 megatons per year of CO2, then that is only about (IIRC) 50/2.35 megatons of carbon, so it is an even smaller fraction of anthropogenic emissions than the 1% figure in my previous post.