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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Barry Moore says:
August 5, 2010 at 9:20 pm
Going back to fig 7.3 in IPCC 4AR they do state that an all time total of 244 GT of anthropogenic carbon has been released but 100 GT has been sequestered in the ocean floor as carbonates, someone mentioned chalk well here it is. That leaves 144 GT between the ocean land and air but the air has 165 GT
I am not at all responsible for the calculation errors of the IPCC…
The only figures of interest are the human emissions and what was measured as increase in the atmosphere. And these show that the emissions were larger than the increase. Thus the difference is somewhere absorbed by nature…
The null hypothesis I offer is bascially that the tail does not wag the dog.
The global ocean establishes the equilibrium level of atmospheric CO2. Absent anthropogenic CO2 the ocean would release a commensurate amount of CO2 to keep the equilibrium point exactly where it is today.
Prove it wrong.
Dave Springer: I’m afraid I don’t have the patience that Ferdinand apparently does, so I am not going to engage in a long debate on this issue, except to point out that:
(i) we don’t need to conduct an experiment to test the hypothesis by reducing anthropogenic emissions to zero, there are other experiments we could perform, for instance we could increase emissions exponentially and see if the resulting rise in atmospheric CO2 were in accordance with expectations. As it happens we have already performed that experiment, it has been ongoing for quite a while.
(ii) You say that the argument is dogma, and yet I have explained why we know that the rise is of anthropogenic origin, and yet you disagree, but have produce no counter argument, or identified any flaw in the reasoning. Are you sure you have identified where the dogma actually lies? ;o)
(iii) I set out a challenge to anyone wanting to assert that the rise is not anthropogenic, namely present a theory where the rise is of natural origin but that is consistent with the annual rise being lower than the level of anthropogenic emissions (as the observations show). I have an open mind, I have fullfilled Poppers requirements and stated how my theory can be falsified. The ball is in your court – go for it.
Dikran Marsupial says:
August 6, 2010 at 3:37 am
‘Imagine you share a bank account with your wife and you put in $8 a year [representing anthropogenic emissions], but never make a withdrawal. If you see that your annual balance [representing atmospheric CO2] rises by only $4 a year, then you know for a fact that your wife [the natural environment] is spending more than she deposits. That means she is opposing the rise in you bank balance, not causing it. You don’t know whether this is because she is spending $4 and depositing $0 a year, or because she is spending $1,000,004 a year and depositing $1,000,000. You know she had spent more than she has put in without going over the detailed statement of all transactions, you only need the balance.’
I understand what you are saying. But I also understand what the others are saying.
You are saying “I’m mad at you. You are spending more than you are depositing”.
While other are saying. “Before you can jump all over you wife, don’t you need to know the rest of the story? Is this a interest bearing account? If so, has the interest rates fluctuated? Have the Bank charges gone up or down? Are bank charge fluctuating a net gain or net lost? Did the bank make an error? If so, did the bank correct the error? Maybe she knows something you don’t?
I suggest comparing UAH satellite temps:
http://www.drroyspencer.com/latest-global-temperatures/
With figure 3 above showing increases of CO2.
Notice something?
The peaks and troughs so seem to match up!
Ok now here is an interesting research question …..why ?
Dave Springer
(i) I have already explained why the mass balance argument is not affected by uncertainties in the individual environmental fluxes between reservoirs here
(ii) For the natural environment to be the cause of the observed rise, it would have to be a net source of CO2 into the atmosphere. We know that none of the possible sources of “natural” CO2 that you mention have strengthened sufficiently to cause the natural environment to be a net source because we observe the annual rise in CO2 to be less than anthropogenic emissions. I made that point in the text you quoted, so you must have read it.
James Sexton says:
August 5, 2010 at 11:26 pm
James Sexton says:
August 5, 2010 at 2:39 pm
Humidity? Did we have more or less H2O then than we do now? Really? I’d like an answer to that.
In what manner does the arrangement of the continents have to do with any thing relating to our discussion? Do you really think that passes as an honest answer? Personally, I can’t conceive of a better insult to a person such as myself.
Temperature was different then? No SH?T!!!!!! Again, I can’t conceive a better insult. Aren’t temperatures the [self snip] topic of our conversation!!??!!! Instead of being dismissive, why don’t you try to explain, for all the world to see, how you believe calcite deposits are relevant.
Sorry that I was a little short in my answer: I have underestimated the number of comments I need to respond to. And yours was rather OT for the subject.
But in short (!):
During e.g. the Cretaceous, ocean temperatures were (much) higher than today (more CO2 in the atmosphere), including the deep oceans, much higher ocean levels and no ice at the poles. Higher temperatures means more water vapor and more rain, causing more plant growth and decay. The continents were drifting away from each other, but still close enough to give free way to ocean flows over the large continuous ocean (which is the main cause of the warm poles…). In that period, enormous quantities of chalk were deposited by algues, like whole South England (the white cliffs of Dover). That reduced in part the amount of CO2 in the atmosphere (and oceans) in deposits which are not easely reached for release today. Still the mass balance holds: what is buried in oil, coal and chalk deposits was once a part of the oceans and atmosphere…
In the current constellation, the North Pole is not easely reached by ocean flows and the increase of the Himalayan heights pushed the western winds more to the north, including the building of the Gulf stream, bringing warmer, wetter air more northly. The availability of a lot of land in northern latitudes is easing the buildup of ice sheets over land, if the temperature drops low enough, which causes a chain reaction with feedbacks (like higher albedo)…
The effect of this all on CO2 levels is about 8 ppmv/C as seen in the Vostok and other ice cores. That only is true for the past probably few million years or so, not applicable for longer time spans where the geological circumstances were quite different.
Bob from the UK. The reason there is a correllation in the peaks and troughs is largely due to ENSO, which affects both temperatures and CO2. IIRC, according to the IPCC, the mechansim by which it affects CO2 is via the effects of El-Nino on the productivity of the terrestrial biosphere.
Old construction worker – I was tempted to add to the analagy a comment pointing out that someone was bound to over-extend the analagy and miss the point, pity I left it out.
The man represents anthropogenic emissions, the wife represents the natural environment (i.e. everything else). As I said, if someone can come up with an explanation why anthropogenic emissions are not the cause of the observed rise that doesn’t imply that the observed rise in atmopsheric CO2 will be larger than anthropogenic emissions, THEN they will have a plausible alternative. However all of the alternative explanations given in the thread thus far, fall at that first hurdle.
Dikran Marsupial says:
August 6, 2010 at 4:32 am
said, “Slioch’s conclusion is not only plausible, it is an understatement”.
Indeed.
There is, of course, another source of “new” CO2 emitted to the atmosphere, in addition to that produced by humans by burning fossil fuels or land-use changes, namely that produced by volcanoes. However, the amount of volcanic CO2, both terrestrial and sub-sea sources together, amount to only about one per cent of human emissions.
I phrase the situation as “the human contribution is more than able to explain the increase” (which is true) rather than “the increase is totally caused by human emissions” with this small caveat concerning volcanoes in mind. If we were living in a time of sudden increase in volcanic CO2 emissions (which we are NOT!!) such that say 10% or 50% of new CO2 came from volcanoes then this phraseology would, I think, be more necessary.
John Egan says:
August 5, 2010 at 8:10 am
As a left critic of AGW, [–snip rest for brevity–]
Prove undeniably, certifiably, and without ANY degree of doubt, that humans are –in any way– responsible for so-called ‘global warming.’
Prove it.
If you cannot, then all your words/pixels are worthless.
PROVE IT.
Further, PROVE –undeniably, certifiably, and without ANY degree of doubt– that there is NO OTHER AGENCY involved.
Prove it.
Can you?
Will you?
Dikran Marsupial says:
August 6, 2010 at 5:34 am
“I’m afraid I don’t have the patience that Ferdinand apparently does”
Nor do I.
“I am not going to engage in a long debate on this issue”
Smart move.
“except to point out that”
“(i) we don’t need to conduct an experiment to test the hypothesis by reducing anthropogenic emissions to zero, there are other experiments we could perform, for instance we could increase emissions exponentially and see if the resulting rise in atmospheric CO2 were in accordance with expectations. As it happens we have already performed that experiment, it has been ongoing for quite a while.”
CO2 emissions have not increased exponentially but I take your point. They have increased. But the temperature of the global ocean has also increased. We know this from precision sea level measurements. Sea level rise is dominated by thermal expansion. Warmer water changes the surface CO2 equilibrium pressure causing either a slowing of CO2 absorption or rise in emission.
How do you propose to separate the effect of rising oceanic temperature and accelerated emission of anthropogenic CO2? This is called isolation of variables and is very important in all manner of investigation.
“(ii) You say that the argument is dogma, and yet I have explained why we know that the rise is of anthropogenic origin, and yet you disagree, but have produce no counter argument, or identified any flaw in the reasoning. Are you sure you have identified where the dogma actually lies? ;o)”
Cute. I’m certainly not holding the dogma. I offered a null hypothesis and asked how it could be disproven. That’s how science works. My null hypothesis could very well be wrong. You however are insisting the science is settled. Proven. Proofs are for math my friend. Science is about best explanations where every explanation is tentative and subject to possible falsification.
“(iii) I set out a challenge to anyone wanting to assert that the rise is not anthropogenic, namely present a theory where the rise is of natural origin but that is consistent with the annual rise being lower than the level of anthropogenic emissions (as the observations show). I have an open mind, I have fullfilled Poppers requirements and stated how my theory can be falsified. The ball is in your court – go for it.”
I have fulfilled your request. You simply dismissed it out of hand which is exactly what dogmatists do.
Ferdinand:
Thankyou for your post at August 6, 2010 at 4:26 am which addresses some of the points I posted at August 5, 2010 at 5:20 pm.
However, you ignore one of my points and selectively quote another (so misrepresenting it).
I can live with your not addressing one of my points because it could be said that you have addressed the issue in responses to others (although, as others have pointed out, your responses are pure ‘arm-waving’).
But in response to my writing:
“Thirdly, your argument is circular. You assume the rise in atmospheric CO2 concentration is an accumulation of the anthropogenic emission then say, “See, the emission is sufficiently large to provide more than the observed increase”. But a change to any other emission (or sequestration) that is larger than the rise could also be said to be sufficiently large to provide more than the observed increase.
And your only justification for choosing the anthropogenic emission as the cause is that we know its magnitude but we do not know the magnitudes of the variations to the (much larger) natural emissions and sequestrations!”
You have replied with the following selective quotation and response:
Your entire quotation of what I said is;
“Thirdly, your argument is circular. You assume the rise in atmospheric CO2 concentration is an accumulation of the anthropogenic emission then say, “See, the emission is sufficiently large to provide more than the observed increase”.
And your answer to that is:
“No, I didn’t assume that the rise in atmospheric CO2 was anthropogenic, I only compared the emissions with the increase in the atmosphere, which shows that it is impossible for the sum of all natural flows to have a net contribution to the rise. Which makes that the increase is solely the result of the emissions…”
But that completely ignores my point that;
“a change to any other emission (or sequestration) that is larger than the rise could also be said to be sufficiently large to provide more than the observed increase.”
Indeed, your ignoring this point proves that you DID (and do) “assume that the rise in atmospheric CO2 was anthropogenic”.
I point out that I said in my post at August 5, 2010 at 5:20 pm which you answered:
“There are several inputs and outputs to the atmosphere that are much larger than the anthropogenic emission. Indeed, as your first (not numbered) figure and your Figure 2 both show, during each year the CO2 in the atmosphere increases then decreases by an order magnitude more than the anthropogenic emission of a year. This increase and decrease within each year is known as the seasonal variation.
So, the annual increase to the CO2 in the air for a year is the residual of the seasonal variation of the year. And the residual is about an order of magnitude less than the seasonal variation which is induced by variations in the natural emissions and sequestrations.”
So, for example, a small reduction to the sequestration by the oceans of the seasonal natural emission could easilly account for the observed rise. And this is NOT “impossible” as you assert.
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.
Is such a change sufficiently large to be measurable? No.
Could such a change have occurred naturally? Yes.
How could such a natural change have been induced? The following is one possibility.
Sulphur ions are released by sub-sea volcanism and are dissolved in the water. The provision of such dissolved sulphur ions will vary with the variation in the volcanism. Centuries after the ions have dissolved they will be transported to the ocean surface layer by the thermohaline circulation and then will provide the change to surface layer pH.
Has this happened or not? Nobody knows and nobody can know.
Is the time-delayed effect on the pH of the ocean surface layer likely to occur? Yes.
So, this possibility of a time-delayed effect on the pH of the ocean surface layer alone could be the entire reason for the observed rise in atmospheric CO2 concentration. Furthermore, it is a more plausible explanation for the observed rise than the anthropogenic emissions because in some years almost the entire anthropogenic emission seems to be sequestered and in other years almost none of it. Hence, the possibility of a time-delayed effect on the pH of the ocean surface layer alone defeats your entire argument.
And there are several other possible explanations for variations in the natural emissions and sequestrations that could be the cause of the observed rise in atmospheric CO2 concentration, too.
Richard
Alex says:
August 5, 2010 at 11:52 pm
Your putting of brackets in the mass balance Eq. is purely political. Mathematics tells us, addition is commutative and it is associative. Thus, your Eq. does not prove anything. Yet, it tells us that the “mankind CO2-emissions” is smaller than the uncertainties in the “natural” sources and sinks of CO2. Thus, the direct mankind CO2-emissions cannot be blamed for CO2 increase. This political preconceived satement diverts us from the search for the real cause of the observed CO2 rise.
OK, my math is a quite rusty, but as far as I remember, putting brackets around a sum of components doesn’t change the sum itself… And I have never heard of “political” brackets… But if you prefer, here without brackets:
dCO2 = in1 + in2 + in3 +… + emissions – out1 – out2 – out3 -…
with the knowns:
4 GtC = in1 + in2 + in3 +… + 8 GtC – out1 – out2 – out3 -…
or rearranged:
in1 + in2 + in3 +… – out1 – out2 – out3 -… = – 4 GtC
Still the natural flows are a net sink for CO2, no addition at all, whatever the variability of the individual flows. The year-by-year variability in total sink capacity is +/- 2 GtC over the past 50+ years, that is all.
Dave Springer says:
“The global ocean establishes the equilibrium level of atmospheric CO2. Absent anthropogenic CO2 the ocean would release a commensurate amount of CO2 to keep the equilibrium point exactly where it is today.
Prove it wrong.”
O.K. If the ocean establishes an equilibrium level for atmospheric CO2 (actually it is not only the oceans; the other elements of the natural carbon cycle also dictate the equilibrium), then the fact that the mass balance argument shows that the natural environment is a net sink means that the equilibrium level is below current levels. Q.E.D.
If we were already at the equilibrium point, then by definition natural emissions would be in balance with environmental uptake – but we know that is not the case.
Portland lemonade stand runs into health inspectors, needs $120 license to operate
Dang. I bet the little girl looked at her cash drawer at the end of the day and thought she’d made a profit.
So much for the cash drawer theory of anthropogenic CO2, eh? lol
Dikran Marsupial says:
August 6, 2010 at 3:37 am “Imagine you share a bank acount with your wife and you put in $8 a year [representing anthropogenic emissions], but never make a withdrawal. If you see that your annual balance [representing atmospheric CO2] rises by only $4 a year, then you know for a fact that your wife [the natural environment] is spending more than she deposits. That means she is opposing the rise in you bank balance, not causing it. You don’t know whether this is because she is spending $4 and depositing $0 a year, or because she is spending $1,000,004 a year and depositing $1,000,000. You know she had spent more than she has put in without going over the detailed statement of all transactions, you only need the balance.”
But you don’t know what she would have done if you hadn’t deposited any money in the bank at all! She might have reduced her withdrawals or increased her deposits (or some combination of the two) by $4, so that the balance would have risen by the same $4 a year, or by some greater or lesser amount, so that the balance might have risen faster or slower, or fallen. What wives do depends strongly – but unpredictably – on what their husbands do. What nature does depends on what man does. The sum does not and cannot answer the counterfactual.
Dikran Marsupial says:
August 6, 2010 at 5:34 am
“(iii) I set out a challenge to anyone wanting to assert that the rise is not anthropogenic, namely present a theory where the rise is of natural origin but that is consistent with the annual rise being lower than the level of anthropogenic emissions (as the observations show). ”
First, we are not asserting that the rise is definitely not anthropogenic. We are asserting that we do not actually know; that the evidence does not prove that it is. A contrary hypothesis would be the very simple one that CO2 is in approximate equilibrium between atmosphere and oceans, so the CO2 level has risen principally due to the rise in ocean temperatures since the Little Ice Age. Under this hypothesis it would have risen at almost exactly the same rate irrespective of anthropogenic emissions. More sophisticated variants of the theory would include absorption and circulation lags for both CO2 and heat, and in those the rise would typically happen a bit quicker with anthrop. emissions than without (and falls a bit later).
Ferdinand Engelbeen says:
August 5, 2010 at 10:09 am
Bill Yarber says:
August 5, 2010 at 8:19 am
I think you have seriously underestimated the impact on the oceans outguessing CO2 as they warm! Look at the ice core data
No I haven’t underestimated the impact of the oceans: over very long term (Vostok ice core) that is about 8 ppmv/C, the same for the MWP-LIA cooling (only visible in the high resolution Law Dome ice core). Currently the short term influence of temperature is about 4 ppmv/C around the trend, but the trend itself is largely from the emissions…
————————————————————————————–
Ferdinand,
Theres no doubt that humans have contributed towards the increase in atmospheric CO2 emissons and thankyou for your explanation, but the question is how much? The key debate in how much this relies on is the assumption that CO2 ice core data is good compared with realty. (instrumental data over the past 1oo or so years)
I had made a post yesterday at 3.40pm that shows scientific evidence that you have seriously underestimated the impact on the oceans outgassing CO2 as they warm. (unless see below at bottem)
The globe and regions of it have shown much lower increases in temperatures with much higher levels of CO2. There are concerns about the loss of atmospheric CO2 when the ice core samples are taken. How accurate would a snow/ice core sample taken from the surface now(or near), show CO2 to be compared with recent instrumental levels?
So why is the ice core data valid and why have you not taken into account the instrumental values of CO2 that don’t show this 1c/8 ppmv rise? With these major differences both can’t be right so which one is wrong and demonstrates different orders of CO2 outgassing from the oceans?
CO2 outgasses from the oceans the same amount via the the same rise in ocean temperature as it does now as then. You must see the very big problem here and can you explain this? Alternately are you suggesting the ice core data is right and the amounts were released from warming oceans from a 1c rise and that means extra CO2 shown from instrumental data is irrelevent and shows no/trace warming effect on the globe over the past 100 years.
Paul Birch
It is perfectly true that we don’t know what the wife would have done had the husband not deposited any money. However, that is irrelevant as we know what she actually did do, and it is what she did do that affected the balance of their bank account, rather than what she might hypothetically have done.
Likewise it is true that if we hadn’t produce anthropogenic emissions, we can’t know for certain what the environment would have done (although the null hypothesis would be that it would continue to follow its behaviour since the start of the current integlacial). HOWEVER, we know that the environment has not been a net source of CO2 as we can infer the net flux via the mass balance argument. So while (through some unspecified mechanism) the environment might have caused a rise in CO2, the obsevations show that it HASN’T.
A scientist doesn’t ignore the data, and the data show unambiguously (via the mass balance argument) that the natural environment has been a net sink throughout the industrial era. Note this is exactly what you would expect from a system in approximate equilibrium; if you disturb the equilibrium (e.g. by putting fossil carbon into the atmoshere) then the system will react to oppose the disturbance.
Julian Flood says:
August 5, 2010 at 11:40 pm
Ferdinand,
Do you have a copy of NASA’a Fig 1 above with error bounds? I’m particularly interested in the plus/minus figures for the carbon export into the deep ocean from the surface ocean. I think I’ve got them on my old computer but it’s a bit flakey, not least because I keep it in the shed.
I have no direct figures, but the error estimates for the ultimate sequestering of CO2 in the oceans and vegetation (based on d13C and O2 balances) are +/- 30% for oceans and +/- 60% for vegetation. As the estimates for the fluxes are based on the same indicators, the error margins may be similar… See:
http://www.bowdoin.edu/~mbattle/papers_posters_and_talks/BenderGBC2005.pdf
For the deep oceans, I have my own estimate, based on the fact that the deep oceans still don’t show contamination by low 13C human carbon: with a refresh rate of about 40 GtC directly (or indirectly via the ocean surface layer) between the deep oceans and the atmosphere, the 13C response is a near fit to the emissions of fossil fuels:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/deep_ocean_air_zero.jpg
But that too is an estimate…
Paul Birch:
Thank you for your fine post at August 6, 2010 at 7:15 am.
Your post says all that really needs to be said: everything else is detail.
Richard
Paul Birch wrote:
“A contrary hypothesis would be the very simple one that CO2 is in approximate equilibrium between atmosphere and oceans, so the CO2 level has risen principally due to the rise in ocean temperatures since the Little Ice Age. Under this hypothesis it would have risen at almost exactly the same rate irrespective of anthropogenic emissions. More sophisticated variants of the theory would include absorption and circulation lags for both CO2 and heat, and in those the rise would typically happen a bit quicker with anthrop. emissions than without (and falls a bit later).”
However, if that were the case, then the annual rise in atmospheric CO2 would be greater than anthropogenic emissions (as both anthropogenic emissions AND the response to increasing ocean temperatures were adding to atmospheric CO2), and as I said, we know from observational data that this is not the case.
There is also as Ferdinand explainer earlier in the thread, the sensitivity of atmospheric CO2 to changes in temperature is far too low to explain the observed rise. Looking back in the paleoclimate data, you only get a change of 100 ppmv at glacial-to-integlacial transitions, when the change in temperature is much higher than the change in temperature between the LIA and now, so that explanation is inconsistent with what we know about past climate anyway.
Slioch Re: volcanos
Very true, however if volcanos started producing 20-50% of emitted CO2 then it would be producing enough for the natural environment to flip from a net sink to a net source, so at that point the mass balance argument would show that the natural environment were a cause of the rise, becuase the annual rise would then be greater than anthropogenic emissions.
Having said which, in science, understatement is generally preferable to overstatement.
Ferdinand Engelbeen says:
August 5, 2010 at 3:37 pm
Paul Birch says: We do not know! The natural cycle is so variable and uncertain, our understanding of all the relevant mechanisms so lacking, and our inability to carry out controlled experiments so limiting, that the realistic error range of any supposedly comprehensive “prediction” would far exceed the magnitude of the observed increase.
“Neither in the (smoothed) ice cores, nor today with very accurate measurements, there is any large variability visible: both the temperature swing over the seasons as the year-by-year variability show some 4 ppmv/C change, nothing more, over the past 50+ years. Thus the possibility of large swings is rather questionable.”
Even in your own graphs the year to year fluctuations exceed the trend increase many times over. The large swings are plain to see. The ice core proxies are not relevant because at best diffusion smears the data over centuries, and CO2 may also have been either lost or added systematically since the inclusions were formed. We know from other sources that extremely large departures from balance have occurred in prehistoric times (eg, supervolcanos have dumped extra CO2 into the air at rates exceeding ten thousand times the current rate of anthropogenic emissions; even ordinary volcanos can make quite a difference; while more speculative possibilities include the catastrophic overturn of CO2-filled ocean trenches, which could temporarily push the global CO2 level up to ~100,000ppm (~10%)!).
“Further, if we stop all emissions today, and the levels wouldn’t drop, then the IPCC is right to claim that (part of) the emissions would stay in the atmosphere forever?”
This seems gibberish to me. If we stopped emitting, CO2 levels would continue to rise and fall over time, as they have always done. The fraction of the atmospheric CO2 that mankind had at some time emitted would gradually fall, due to interchange with the other reservoirs; but it would never fall to zero because atmospheric CO2 makes up a finite fraction of the total.