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michael sweet | January 16, 2017 at 20:09

Your comment to D-C-S
"You need to look up some peer reviewed papers."

The link provided by D-C-S was correctly validated with 736 Citations:-
See all › 736 Citations See all › 62 References

Siegenthaler U, Sarmiento JL. 1993. Atmospheric carbon dioxide and the ocean. Nature
Article in Nature 365(6442):119-125 · September 1993 with 61 Reads
DOI: 10.1038/365119a0

Your first link; read carefully the section 'Carbon Cycle and Atmospheric CO2'.
This section fully contradicts your position.

Your second link; this is to a Blog frontpiece managed by, Robert Monroe, a journalist. This point was made in a previous comment to Rob Dekker but there was no response from him to the comment.

It appears that you are confused about the CO2 that enters the ocean and is re-emitted to the atmosphere (Short-term Global Carbon Cycle) and the CO2 that eventually sinks to the bottom of the ocean and remains there (Long-term Global Carbon Cycle).

There is no scientific dispute about the CO2/Oceanic fux.

If you want an IPCC published paper with clear explanation to help try:-
Look at Fig 7.3 for a good visual representation of what is happening.

Rob Dekker

DCS said

If CO2 emission were to stop in the short term then CO2 absorption by the oceans would almost stop in the short term

You just keep on going with this myth, don't you ?

If we stop emissions today, then tomorrow CO2 concentration in the atmosphere is virtually unchanged. So the oceans will continue their absorption rate, and not almost stop in the short term.

Are you playing games, trying to see how far you can go denying basic physics ?

Rob Dekker

Regarding the Scripps paper, you mentioned

Monroe revert to type, with a conclusion in his own words that were not supported by the referenced paper.

to which I asked :
I am really looking forward to your explanation of where Monroe's summary was "not supported by the referenced paper" as you claim.

Still waiting for that explanation, D-Penquin


Rob Dekker | January 17, 2017 at 06:13

I am enjoying the debate but definitely not playing games. I think it would be great if we could 'drill down' to the point(s) where our respective opinions diverge and then, hopefully, form a consensus point of view.

For example, my reply to your comment below might be a starting point. Perhaps you could pick up on one or more of my responses and point out where we differ and why.

Rob Dekker | January 17, 2017 at 06:17

It is very difficult to explain something that is not there but I will try.

1. Monroe fails to differentiate between the atmospheric CO2 that is absorbed by the ocean and then emitted back into the atmosphere over the short-term and the atmospheric CO2 that is processed by interaction with the ocean and then sinks to the ocean bed where it remains as sediment for the long-term.

2. Monroe fails to account for the Atmospherice/Ocean CO2 flux that controls the absorption and emission rates of CO2 at the surface ocean.

3. Monroe fails to account for the change in sign (-ve to +ve and +ve to -ve) as the concentration level of CO2 in the atmosphere is reduced beyond the hydrostatic CO2 molecular pressure equilibrium point at the surface ocean.

Therefore, in my opinion, Monroe's summary is incomplete and misleading.

Does this explanation help?


Michael Sweet, D-Penguin:

I don't know how many times I need to repeat this: The CO2 transfer between the atmosphere and the ocean is driven by the concentration in the atmosphere, in particular by the difference from equilibrium, not by the rate of emissions of CO2.

The CO2 transfer between the atmosphere and the ocean is driven by the concentration in the atmosphere, in particular by the difference from equilibrium, not by the rate of emissions of CO2.

The rate of absorption by the ocean is proportional to the deviation from equilibrium.


Instead of differential equations you may use parables like JC to his disciples.
Either way, what Rob Dekker says makes a lot of sense and if scientists have calculated that those are the rates of carbon trapping... The ocean surface will not notice that you and everybody else stopped burning fossil fuels. The ocean surface just notices that the CO2 concentration is 400 ppm and swallows as much as dictated by that concentration and by the rest of conditions, next year 398 ppm, next year it will be 396 ppm and so.


Rob Dekker:

Apparently you didn't understand my last comment. I don't know how to address that problem at this time. Maybe I'll think of something later.

Do you agree with one of the points in particular?

The points were:

1. The effect of transfer of CO2 between the atmosphere and the near-surface ocean is fast compared to significant effects of longer term processes (such as ocean circulation and removal of carbon from the ocean as dead plankton sink to the bottom and end up in the sediment). So as CO2 is emitted on an annual basis, a corresponding proportion of it goes into the oceans on an annual basis. It states "The gas-exchange rate is fast enough to ensure that surface-water CO2 is near equilibrium with the atmosphere (except in ocean regions where vertical water exchange is vigorous) … The global mean ΔpCO2 is so small because surface sea water reaches chemical equilibrium with the atmospheric CO2 concentration within a year, whereas the timescale for downward transport from the surface to deeper layers in the ocean is considerably longer." on page 121 of the article at this link: https://www.gfdl.noaa.gov/bibliography/related_files/us9301.pdf

2. As about 30% of added CO2 has been absorbed by the oceans on an ongoing basis, the short term relationship between emitted CO2 and CO2 absorbed by the oceans is approximately linear in the short term.

3. If there is a linear relationship between two variables (that are each a function of time), such as y = m x + b (x & y variables, m & b constants), then the rates of change of those variables are proportional. In the example, (Δy / Δt) = m (Δx / Δt) for average rates, and (dy / dt) = m (dx / dt) for instantaneous rates.

4. If the rate of CO2 emission were to halve in the short term then the rate of CO2 absorption by the oceans would about halve in the short term. If CO2 emission were to stop in the short term then CO2 absorption by the oceans would almost stop in the short term, but would continue at a slow rate due to longer-term effects.

Your claim that "Back to first principles: if we eliminate CO2 emissions today, atmospheric CO2 would go down at a rate of about 50% (25% to oceans and 25% to land plants). This suggests that if we would cut emissions by 50% today, that atmospheric CO2 levels would stay level (at least for a little while)." is wrong because, as stated at the link that I posted, "SURFACE SEA WATER REACHES CHEMICAL EQUILIBRIUM WITH THE ATMOSPHERIC CO2 CONCENTRATION WITHIN A YEAR" (bold added).



Yes, you got it right.





navigante: PS

Differential equations are extremely relevant to the topic at hand, but one can easily get by without them in the current context, mainly because equilibrium between surface sea water and atmospheric CO2 concentration is reached so quickly.


Quasi-equillibrium. CO2 keeps sinking



Yes, I also mentioned that in earlier comments.


"Thus, the main rate-determining step for oceanic uptake ... is the vertical water transport"
the same paper says. Which leads me to believe that in one year ~8 ppm reduction (of the order, not equal to), and next year would be similar, a process of decades, but as Rob and others said above, it would be very noticeable.

Note that the sinking is so slow that the atmosphere-ocean CO2 transport seems to be in equilibrium (is not, it is in Quasi-equillibrium and will be the following year, and the following and so for a few tens of years)



That would refer to the long term rate. However, if there were a sudden significant increase or decrease in the CO2 emission rate then the absorption rate by the near-surface ocean would respond rapidly, not to the rate change, but to the ongoing change in the atmospheric CO2 concentration.


D_C_S | January 17, 2017 at 18:54

D-C-S, I entirely agree with you. My argument has always been the SAME as your argument.


D_C_S | January 17, 2017 at 18:54

Are you confusing me D-Penguin with FishOutofWater?

We were both D and I changed to D-Penguin to avoid confussion. FishOutof Water still posts as D but not contributed to this discussion for a long time.


Hello all-- great blog, and you finally got me to sign in with The Great Absorption Rate Debate.

I think DCS is both right and possibly wrong, so let me see if going back to basics helps clarify.

Assume a container with water and air-- in effect a closed system.

After some time, the air and water will reach an equilibrium concentration of CO2-- "the right amount" in the water, and "the right amount" in the air.

Now, let's say we add X CO2 to the air, and it takes just a second to evenly mix in the air.

There will now be some elapsed time t before a new equilibrium is reached between water and air.

In an identical container with identical initial condition, we add 2X of CO2, and it likewise takes a second to evenly mix in the air.

If it takes the same time t to reach its new air/water equilibrium, then it is proper to say that the rate of absorption has doubled, [x/t, 2X/t], as a consequence of doubling the rate of increase of CO2 in the air.

That's the "DCS is right" part.

But the question is, will t indeed be the same in each case? In this simple example, where there is simply molecular exchange across a plane surface boundary, I would say "yes" as long as the water is reasonably far from saturation.

DCS is claiming that, in the short term, where deep mixing causes little change, the closed system analogy is correct. What isn't clear to me, though, is whether "equilibrium is achieved in a year" is sufficiently precise to tell us that t is in fact independent of the rate of increase of CO2 in the air. DCS?

(Please note-- I have no expertise on the real-world situation so I am asking that without preconceived answer.)



[Final warning, N.]


navegante | January 17, 2017 at 19:46

"Thus, the main rate-determining step for oceanic uptake ... is the vertical water transport"
CORRECT - BUT the oceanic 'up-take' (long-term event) of CO2 is not the same as the absorption (short-term event) of CO2 at the Atmospheric/Oceanic interface. The vertical water transport returns most of the CO2 back to the surface ocean; only a small fraction will sink to become sediment on the ocean bed.

"Note that the sinking is so slow that the atmosphere-ocean CO2 transport seems to be in equilibrium (is not, it is in Quasi-equillibrium and will be the following year, and the following and so for a few tens of years)
NOT CORRECT - BECAUSE the absorption at the surface ocean is dependent on the Atmospheric/Ocean CO2 flux, that is, the diferrential between the hydrostatic molecular pressure of CO2 in atmosphere and ocean respectively. The current flux value is -ve, if the CO2 concentration in the atmosphere decreases then the hydrostatic molecular pressure decreases and the absorption of CO2 at the surface ocean decreases. This process would continue until the hydrostatic molecular pressures equalised, at the equilibrium point the ocean absorption would be equal to emission. If the process continued, the hydrostatic pressure of CO2 in the ocean would be greater than in the atmosphere and the ocean absorbtion would be less than the emission of CO2 returning back into the atmosphere. That is, flux sign would reverse and become +ve and there would be a net gain of CO2 by the atmosphere.

NOTE When scientists refer to the percentage of CO2 absorbed by the ocean, they are referring to absorption at the surface ocean and NOT the CO2 lost in the vertical transport in the middle ocean that eventually gravitates to form sediment at the ocean bed.


zebra | January 17, 2017 at 21:37

Unfortunately the analogy is not entirely correct. To all intents and purposes the system is an open system because the ocean could, in theory, absorb all the CO2 presently in the atmosphere.

What you have to consider is the 'ability' of the water to absord the CO2 and this is determined by the CO2 concentration in the Air and water respectively. This relationship is called the Air/Water Co2 flux. For a more detailed explanation of the Atmospheric/Oceanic CO2 flux please refer to my comment D-Penquin | January 17, 2017 at 22:38 in reply to Navegante.


zebra | January 17, 2017 at 21:37

Just a postscript: D-C-S is correct.


zebra | January 17, 2017 at 21:37

I should have started with:-
Great that you are enjoying it and hope that you continue to post your comments, whichever side of the debate.

There are also some great contributions and opions on Global sea ice records broken (again), this is the current subject; just in case you had not bothered to give it a read yet.


Ok just please somebody answer these 2 questions: how does a region of ocean interface somewhere in the Pacific notice that one year before a virus killed all human kind and emissions have stayed zero ever since?. And, why in that moment the ocean will start to release CO2 overall, instead of keeping uptaking CO2?
I dont get it :) sorry

james cobban

Navegante et al, I think D_C_S and D-Penguin are arguing that the surface of the ocean is already in equilibrium with an atmosphere containing about 400 ppm CO2, with a time lag of about a year. So the ocean cannot absorb any more CO2 unless the atmospheric concentration were to rise. Of course, it did rise in the course of the last year, to about 403ppm, so the ocean can continue to absorb CO2, at least for another year. If we emit more CO2 in that time, then the ocean will continue to absorb that new CO2, and so on. If we stopped emitting all CO2 today, then in about a year the oceans would attain equilibrium a year from now with an atmospheric CO2 of about 403ppm, moving from their current equilibruim with an atmosphere of 400ppm.

This, at least, is how I understand their position. I don't have the knowledge to comment on the validity of their argument, but D_C_S provides a link that states, as he says, that "SURFACE SEA WATER REACHES CHEMICAL EQUILIBRIUM WITH THE ATMOSPHERIC CO2 CONCENTRATION WITHIN A YEAR" (bold added).

The surprise to me, if this is correct, is that the surface ocean basically does not provide any short-term CO2 absorption potential at all (after a one-year lag), because it is already nearly at equilibrium with the atmosphere.

In your scenario, then, humans would stop emitting CO2 and it would stay at 403ppm. The oceans are already in equilibrium with a 400ppm atmosphere, and so would continue to absorb CO2 until they came into equilibrium with the 403ppm atmosphere, which would take about a year, at which point they would stop absorbing any further CO2.

Is this about right, D_C_S and D-Penguin?

r w Langford

The word "surface" means just that, it does not mean several kilometres of atmosphere.Equilibrium between two surfaces is significantly different from an atmosphere and an ocean. Perhaps that is part of the misunderstanding?


james cobban | January 18, 2017 at 01:21

James, D-C-S and I agree on the 'principles' of the matter with possible minor variations on the details that may be due to style of presentation or interpretation.

My position is:-
Atmospheric/Ocean CO2 flux is currently -ve and increasing slightly at the present time, that is, the surface ocean is absorbing more CO2 than it is emitting back into the atmosphere. The reason for this, despite a slight reduction in anthropomeric fossil fuel emissions over the past two years, is that the concentration level of CO2 in the atmoshere has increased because of the 'lag' that you referred to and possibly other factors.

However, the point is, that the 'equilibrium' state is not a constant(it is sometimes referred to as a quasi-constant). At the present time, the carbon part of CO2 entering into the atmosphere, breaks down as follows:-
1. Anthropomeric burning of fossil fuels that enter the atmosphere is ~10Gt pa
2. Total carbon entering the atmosphere is ~38Gt pa
3. Total carbon entering the surface ocean is ~24Gt pa
4. The increase of carbon entering the circulation of the intermediate deep ocean is ~2.8Gt pa
5. The carbon falling by gravity to become sediment on the ocean bed is approaching ZERO (that is, taken out of the Global Carbon Cycle for millenia)
- The Atmospheric Sink contains ~870Gt
- The Vegitation, Soil and Detrius Sink contains ~2,300Gt; additionally, the ground contains ~3,500Gt (fossil fuel reserves).
- The Ocean Sink (sediment) contains about ~150Gt of carbon; additionally and in circulation, the Top Ocean contains ~920Gt, the Biota contains ~3 Gt, the Intermediate and Deep Ocean sediment contains ~37,300Gt.

So, the Atmospheric/Ocean CO2 flux will only move towards equilibrium if the CO2 concentration levels in the atmosphere reduces sufficiently to allow the atmospheric molecular pressure of CO2 to equal the hydrostatic pressure of CO2 in the Ocean. If reduction continued the ocean would obsorb less CO2 than it emitted.

Therefore, the time taken to reach 'equilibrium' will be, mainly determine by a function of the rate of decrease of the concentration level of CO2 in the atmosphere and time.
Other factors come into play; for example, sea surface temperature (CO2 is absorbed more quickly in colder than warmer water), the capacity of the other sinks to absorb CO2 from the atmosphere, the weather and the turbulance of the sea.

Rob Dekker

DCS, could you please confirm or deny that james cobban summarized your position correctly ? A simple yes or no would greatly help in moving this discussion forward.

Rob Dekker

Sorry to drive this through, but regarding the Scripps paper you said :

with a conclusion in his own words that were not supported by the referenced paper.

When I asked you (twice) about which conclusion you are talking about you answered

It is very difficult to explain something that is not there

And you elaborated on something that was NOT in Monroe's paper.

So WHICH conclusion IN HIS OWN WORDS are you talking about ?

Its kind of important, because you are accusing Monroe of writing something that is not in the referenced paper, but when confronted you are stating only things that Monroe never wrote.

So what exactly is it that bothers you about Monroe's paper ?

Rob Dekker

Sorry. That last sentence should read as follows :

So exactly WHICH conclusion that Monroe drew IN HIS OWN WORDS was not supported by the referenced paper ?


James Cobban,

This is about correct if you include the hypothetical constraints as I described in my previous comment-- we assume a negligible time for the CO2 to mix into the atmosphere, and we disregard transport removing CO2 from the surface water.

Also, remember that this refers to direct molecular exchange between air and water, and disregards the other mechanisms that transport CO2 into the ocean or sequester it from the atmosphere and ocean.

To try to simplify D-Penguin's explanation: At the (hoped for) magical moment when we stop putting fossil carbon into the atmosphere, the other mechanisms-- deep ocean transport, mineralization, biomass, and so on-- will engage in a push-pull kind of contest. So, for another simplified scenario:

We have my closed container with water and air at CO2 equilibrium. There's a little island in the middle with a plant growing on it, and in the water is a clam. Depending on which is growing faster, CO2 molecules will cross the surface boundary in one direction or the other to establish new (lower) equilibrium points.

Of course, as I said, I don't know all the numbers for the incredibly complex real-world interactions. I think that even the scientists who work on this would tell you that they are not all that clear on how long it will take to "draw down" the CO2 to pre-industrial levels.

It probably will be slower than we would like, but whether that requires active human intervention is also not clear.

Bill Fothergill

I was away from the internet for several days and, upon my return, have discovered that it's Groundhog Day on this thread.

Consequently, I fired off three quick emails this morning; one each to David Archer, Pieter Tans and Ralph Keeling. In each case, I outlined the somewhat intransigent debate that has been rumbling on here for some time, and asked if they would be kind enough as to share their own perspectives.

With any luck, at least one of these gentlemen will be able to provide us with a definitive response.

David Archer is a professor in the Department of Geophysical Sciences at the University of Chicago, and is also author of various books, including "Understanding the Forecast", and, of particular relevance to this debate, "The Global Carbon Cycle".

His areas of research focus are ...
Global carbon cycle, climate change, aqueous chemistry

Pieter Tans is Chief, Carbon Cycle Greenhouse Gases Group at NOAA's Earth Systems Research Laboratory.

His team are responsible for the development and maintenance of NOAA’s Global Greenhouse Gas Reference Network.

Ralph Keeling is a professor at the Scripps Institution of Oceanography at San Diego. His main research areas are given as: Atmospheric Aerosols & Chemistry, Climate Sciences, and Past Climate Change.

Additionally, I asked Professor Keeling if he would care to comment on whether an article resident on the Scripps website represented an accurate summation of his position, or whether the author had inserted his own bias into the summation. The possibly contentious article being...


For James Cobban-- I was reminded by Bill's reference of one other thing I wanted to point out to you, which may be a source of confusion. (Also for Navagante.)

You should keep in mind that the ocean being in equilibrium with the atmosphere is not the same as the ocean being saturated. You said:

"the surface ocean basically does not provide any short-term CO2 absorption potential at all (after a one-year lag), because it is already nearly at equilibrium with the atmosphere. "

The potential is there, depending on degree of saturation, to absorb more CO2. But it will not happen unless the equilibrium is broken by more CO2 in the atmosphere.


It can also be broken by less CO2 in the water near the surface because CO2 is migrating (slowly) toward the bottom of the ocean


James Cobban:

That's pretty much in line with my position.



Three water tanks are each partially full. Their bases are all at the same horizontal level. There is a pipe from the base of the first tank to the base of the second tank. That pipe has a tap that is turned on, so water can rapidly flow between the first and second tanks. There is a pipe from the base of the second tank to the base of the third tank. That pipe has a tap that is turned off, but there is a small leak, so water can trickle at a slow rate between the second and third tanks. There is not a pipe between the first and third tanks.

Each tank is box-shaped (ie in the shape of a rectangular parallelepiped), with one vertical edge-direction. The horizontal dimensions of the first tank are 2 X 2, the horizontal dimensions of the second tank are 1 X 1, and the horizontal dimensions of the third tank are 10 X 10.

The water in the first tank represents atmospheric CO2. The water in the second tank represents the CO2-equivalent that is in the near-surface ocean. The water in the third tank represents the CO2-equivalent that is in the deeper ocean.

Each tank is only partially full. Initially, the level of the upper surface of the water is the same in each tank, so the water pressures are at equilibrium, and there is not any flow between the tanks.

Starting at some time, water is added to the first tank at an increasing rate, and the water level in the first tank rises. Driven by the difference between the water levels and pressures in the first and second tanks, water flows from the first tank to the second tank quickly enough that the water levels in those tanks are continuously almost the same, as they both rise, so they rise at about the same rate. Because the second tank has a smaller horizontal cross-section than the first tank, the volume of water in the second tank changes at a slower rate than the volume of water in the first tank, but the rate of change of each of those volumes is roughly proportional to each other and to the volumetric flow rate into the first tank, as the latter flow rate increaes. There is a trickle of flow from the second tank to the third tank, but that flow is negligible in the short term, and the rate of rise of the water in the third tank is very slow, so the water level in the third tank doesn’t nearly keep up with that in each of the other two tanks.

At some point the rate of flow into the first tank is halved. If the flow rate into the second tank were to remain the same then the water level in the second tank would rise faster than that in the first tank, which would contradict the fact that the flow between those two tanks is driven by the pressure difference and that it tends to equalize the water levels in those two tanks.

If the flow into the first tank were to stop at some time, then flow from the first tank into the second tank would quickly almost stop as the water levels in those tanks were equalized. However, there would still be a trickle of flow from the first tank to the second tank to compensate for the trickle of flow from the second tank to the third tank.

If the flow into the first tank were permanently stopped, then eventually the bulk of the added water would end up in the third tank because of its larger horizontal cross-section.


"A major factor governing the rate of uptake of CO2 by the oceans is pace at which global CO2 emissions are increasing over time. Over the past decades, fossil emissions (measured as tons of carbon) have grown at 2 to 4 percent annually, from around 2 billion tons in 1950 to 9 billion tons today. The oceans as a whole have a large capacity for absorbing CO2, but ocean mixing is too slow to have spread this additional CO2 deep into the ocean."



I usually have only a short time each day to read and reply to comments here, so I probably misinterpreted one of your comments as I read it in haste. I wasn't sure that I was interpreting it correctly at the time.


James Cobban:

That's pretty much in line with my position, except that the ocean would still be able to absorb CO2 at a slower rate because of ocean circulation, etc.


Great analogy DCS thank you. I see it that way too. That leak, as little as it is, it is responsible for a large fraction of CO2 removal already, isnt it?


Rob Dekker | January 18, 2017 at 07:56

Rob, no need to apologize for driving through on a point; If we are not driving, we will never reach the destination (well, you know what I am trying to say).

AND you make a valid point.

The following quotes are not edited but lower case changed to upper case to emphasise.

The Paper said:-
"A major factor governing the rate of uptake of CO2 by the oceans is the pace at which global CO2 emissions are increasing over time. Over the past decades, fossil emissions (measured as tons of carbon) have grown at 2 to 4 percent annually, from around 2 billion tons in 1950 to 9 billion tons today. The oceans as a whole have a large capacity for absorbing CO2, BUT OCEAN MIXING IS TOO SLOW TO HAVE SPREAD THIS ADDITIONAL CO2 DEEP INTO THE OCEAN."

Monroe (1) said:-
"The oceans as a whole have a large capacity for absorbing CO2, BUT OCEAN MIXING IS TOO SLOW TO HAVE SPREAD THIS ADDITIONAL CO2 DEEP INTO THE OCEAN."

Monroe (2) said:-
"As emissions slow in the future, the oceans will continue to absorb excess CO2 emitted in the past that is still in the air, and this excess WILL SPREAD INTO EVER-DEEPER LAYERS OF THE OCEAN."

Monroe (3) said:-
"The ocean uptake, when expressed as a percent of emissions, will therefore inevitably increase AND EVENTUALLY, 50 TO 80 PERCENT OF CO2 CUMULATIVE EMISSIONS WILL LIKELY RESIDE IN THE OCEANS, KEELING SAID."

My opinion:-
Monroe (1)
Correct - No Contradiction with Paper

Monroe (2)
Incorrect - Self-contradiction - Contradiction with Paper
The inference here must be that the CO2 in the oceans will eventually become sediment at the ocean bottom (WILL SPREAD INTO EVER-DEEPER LAYERS OF THE OCEAN).

Monroe (3)
This is not related to the Paper. However, it does relate to the preceeding sentence Monroe (2), or at least that is how it reads.
Again, the inference must be in this case, that 50 to 80 percent of the CO2 in the atmosphere will eventually be absorbed and "reside" in the ocean. So, it begs the question, which scenario does it fit into, the Paper and Monroe (1) or Monroe (2)?

In conclusion, the article is contradictory and misleading. I would think that nearly every reader of the Article would think that by reducing CO2 emissions into the atmoshere, eventually, the oceans will remove 50 to 80 percent of the remaining CO2 in the atmoshere. The Article fails to 'explain' what happens to all this CO2 that has been absorbed by the oceans. Where does it all go to? What is its 'final destination' in the Global Carbon Cycle?

So, again Rob, it was the lack of context and more about what was not said, amplified by the error (inconsistency).

I tried - Does this help?


navegante | January 18, 2017 at 19:14

"That leak, as little as it is, it is responsible for a large fraction of CO2 removal already, isnt it?"

Answer: No, it isn't.

A more realistic analogy would be:-

The tap is running at full bore into Tank 1 for a 1,000 years and two drips are lost through the leak from the connection between Tank 2 and Tank 3

The tap is turned to half bore and runs for a 1,000 years and one drip is lost through the leak from the connection between Tank 2 and Tank 3

THEN, consider how large the fraction of CO2 removed might be.

THEN, compare the real Oceanic Carbon Sink.
The total carbon captured from atmospheric CO2 over eons of years and deposited as sediment on the ocean bed is 150 Gt.

THEREFORE, how much carbon from atmospheric CO2 in the atmosphere over, say 1,000,000,000 years, has been deposited as sediment on the ocean bed each year.
150 Gt divided by 1,000,000,000 years
= 0.000000150 Gt per year
Atmospheric CO2 circulating in the Intermediate and Deep Ocean (where the carbon sediment eventually comes from) is 37,200 Gt.
The fraction of atmospheric CO2 absorbed by the ocean that escapes from the Intermediate and Deep Ocean to fall and form sediment on the ocean bed is such a small fraction that it can be considered as approaching ZERO.

Rob Dekker

Thank you James Cobban, for clarifying DCS' position, and thank you DCS for confirming, and also for your great analogy (with the three tanks).

Now it is time to crank the numbers.

In the same paper (from 1993) where DCS found the statement that "surface sea water reaches chemical equilibrium with the atmospheric CO2 concentration within a year" :
there is figure 1 which shows the fluxes and storage of carbon (in and between the three tanks).

There you see that for an atmospheric increase of 3.4 Gton/year, the surface ocean absorbs about 0.4 Gton/year. That is only 12% of atmospheric increase. The bulk of the carbon that goes into the oceans descends down to the deep ocean. In DCS' analogy, the flow of water between the second and third tank is not a 'trickle' but in fact a solid flow of 80% of flow between the first and the second tank.

This makes sense, because the surface ocean not only has a short time constant, but also a very limited amount of storage capacity.

So, Navegante is right. The leak between tank 2 and tank 3 is responsible for a large fraction of CO2 removal. And that flow is very stable and tank 3 is insanely large (already contains some 38,000 Gton carbon (not a typo)).

Back to first principles : Given these numbers, if we stop emitting right now, atmospheric CO2 will start to fall at a rate of about 2ppm/year, (since all the carbon sinks continue as they are today), this rate of decline will be reduced by some 12%, because the surface ocean is no longer accumulating carbon. And (again in this super simple model) if we cut emissions in half today, CO2 atmospheric levels will level off, but after 1 year start to increase at 12% of previous rate.

Do we all agree on that now that the numbers are in ?

Rob Dekker

Important note is that we are working with a very simple model here.
That is good, to get the conceptual points agreed upon (which we seem to have a hard enough time with), but in reality ocean-atmospheric CO2 exchange and surface-deep ocean carbon exchange is pretty chaotic with wide temporal and spatial variability.

One example of that is at some point it looked like the Southern Ocean was not absorbing more carbon (like a 30 year 'pause') despite a sustained increase in atmospheric CO2. Work reported by Le Quere et al. [2007]. Later work showed that the Southern Ocean actually did pick up the pace again, but the natural variability in that sink is quite significant (nothing like "equilibrium" within a year or so).
David Archer did a pretty good piece on that development here at RealClimate :

Rob Dekker

D-Penquin, I don't see anything "misleading" in Monroe's paper.
Monroe (1) is sustained by the paper
Monroe (3) is sustained by Prof. Keeling's statement (and the bulk of evidence that comes with that)
Monroe(2) is Monroe's own statement, which is sustained by BOTH the paper AND Prof. Keeling's statements.

I guess we have to agree to disagree in this case.


Rob, I highlighted the words in two seperate sentences in the same paragraph, written by Monroe, that contradicted each other. One was correct and the other incorrect. An independent comment confirmed agreement with the correct version. You concluded that all three comments agreed. I do not understand that logic.

Agreed, we agree to disagree on this one.


Rob, do you think that this link from IPCC Climate Change 2007: Working Group I: The Physical Science Basis


could be a useful and simple model to help progress the debate? The link is to a very clear pictorial diagram and it is IPCC approved, so perhaps a good starting point.


For "both/all sides",

I don't know if this has been referenced previously, but I found it useful both in the descriptions and in the graphics that give some quantitative insights:


For DCS,

I don't want to overly complicate your analogy in an attempt to make it more congruent with the actual system-- it does help understanding-- but I think you have to at least add a pipe connecting the third tank with the first tank, with a one-way valve allowing flow from 3 to 1.

This is where I think Navagante and Rob Dekker may be missing the point. The third tank (ocean below say 1km) is going to return CO2 to the atmosphere by upwelling as described in the reference, in addition to returns from the surface ocean, when my plant on the island sequesters CO2 from the atmosphere and breaks the equilibrium.

james cobban

Thank you all for putting so much time and effort into explaining your various positions. I've certainly learned a lot about the flux of CO2 across the air/sea surface boundary.

But I'm still confused on the main point. D_C_S seems to be quite adamant that surface-to-deep-ocean mixing is a very slow process, contributing very little to a short-term reduction in atmospheric CO2. If he's right then if we stopped emitting CO2 today, then after a year or so CO2 would remain near 403ppm, with the ocean contributing to only a very slight yearly reduction - practically none at all.

But if Rob Dekker is right, then the transport of CO2 from surface-to-deep-ocean is much quicker, the equivalent of removing about 2ppm CO2 from the atmosphere each year. If we stopped emitting today, then, in simple terms, the oceans would continue to remove about 2ppm CO2 from the atmosphere for many years, presumably until some new (pre-industrial?) equilibrium was reached.

This is what I had always understood to be the case, but both sides seem to point to strong supporting evidence. Perhaps Bill will clear this up if/when he hears back from his scientist friends.

It's an important point since it would seem to add more than a touch of hopelessness to our situation if we cannot count on the oceans to quickly draw down the atmospheric CO2 after we stop emitting.

Is it possible that what's adding to the confusion is the difference between ocean-bottom sediment formation, which removes only an insignificant amount of CO2 each year, and surface-to-deep-ocean mixing, which perhaps transports relatively large amounts of CO2 to the deep ocean layers each year?



I think the reference I gave might be helpful if you have the time to read it.

The problem may be that people are visualizing mechanisms in different ways and conflating time-scales.

You are correct to note the difference between sedimentation and mechanical transport of "dissolved" carbon.

Sedimentation is actually "re-fossilizing" the carbon, whether in organic or inorganic forms. After all, where did the disgusting black goo come from in the first place?

But, if you look at the figure 7 in my reference, the deep water actually has a higher concentration of C (in various forms) than the surface. So, if you think about it, if you exchange deep and surface water, that in itself can create a dis-equilibrium such that the ocean becomes a source rather than a sink.

That carbon has not been sequestered like what's in the sediment, or what goes into terrestrial biomass that is preserved, or formation of minerals. It is being diluted, but if you disregard the sequestering processes, in the end you will still be somewhere above pre-industrial.

As I said earlier, I don't think you can get a definitive answer about the rate of reduction by scanning some papers, because the people who write the papers are not sure themselves. But I think we can be optimistic that if we stop burning fossil fuels in 100 years, humans will be OK (aside from other ways we like to destroy ourselves.)

Bill Fothergill

"Perhaps Bill will clear this up if/when he hears back from his scientist friends "

As if by magic...
Response No 1: From Pieter Tans at NOAA's ESRL

"Dear Mr. Fothergill,

What happens if CO2 emissions were halved suddenly? Over the last decade, not including the 2015-16 El Nino which has not finished yet for CO2, about a quarter of the emissions went into the oceans and another quarter into the terrestrial biosphere. We can expect that to continue initially so that the CO2 increase would stop, initially.

However, the ocean partial press of CO2 increases, while it does not in the atmosphere. Therefore the difference of atmosphere minus ocean partial pressures would eventually be cut in half (my guess - this can be modeled, though) so that the ocean uptake would also be about half.

I don't know how the terrestrial biosphere would react. It depends on the actual strength of the "CO2 fertilization" effect, and to what extent it is counteracted by nutrient deficits. Neglecting nutrients, pure CO2 fertilization would eventually peter out when atmos CO2 growth stops. Biomass would keep increasing until the accompanying increased respiration/decay balances the increased rate of photosynthesis. Since most of the respiration comes from the more "labile" recent biomass the majority of that balance could be restored in 10-20 years. However, in this half-emissions scenario CO2 keeps increasing, although at the slower rate. Therefore one would expect the CO2 fertilization effect to weaken also in 10-20 years, but not stop. I note, though, that human activities have a massive influence on nutrients so that would likely play a major role.

Henry's Law says that the solubility of CO2 in water decreases at higher temperature of the water. So a warmer ocean surface would dictate that more CO2 remains in the atmosphere. This argument is independent of the previous paragraph, and would work in parallel. The deep ocean circulation might slow down with a warmer surface ocean because the density of surface waters would decrease. This could really slow down, at least temporarily, ocean CO2 uptake. There are other potential knock-on effects such as build up of organic matter in deeper waters and oxygen deficits etc. I am not going to make predictions. There could also be stronger winds in the new climate that might stir up the ocean circulation....

We can actually predict the long-term partitioning of the extra CO2 between the oceans and atmosphere IF we assume that ocean circulation and ocean biology stays the same, and also assuming that the terrestrial biomass has zero net change since pre-industrial times. In other words if the partitioning of the excess CO2 depends only on known carbonate chemistry. In that case ~17% stays in the atmosphere "permanently" and 83% in the oceans.

CO2 has also been correctly called "carbonic acid in the air" by Arrhenius in his 1896 paper. The added acid will eventually be neutralized by decreased calcification rates by organisms and by dissolution of a fraction of bottom calcium carbonate sediments. The net reaction is CO2(atm) + CaCO3 (solid) + H2O ---> 1 Ca(2+) ion + 2 HCO3(-) ions. Nice, it has been turned into a component of sea salt. The capacity of the oceans to hold carbon has increased. We cannot wait for that, however, current estimates are that it might take 3000-7000 years. It is another illustration of how current rates of fossil fuel burning outstrip the rates of natural processes by a factor of 100. This last number is the most important one to keep in mind.

Best regards,
Pieter Tans"

More to follow from Ralph Keeling & David Archer


CO2 has also been correctly called "carbonic acid in the air" by Arrhenius in his 1896 paper."

Bill, at that time CO2 was variously called carbon dioxide, carbonic acid gas or carbonic acid, sometimes in the same paper.

As for CO2 - ocean equilibrium, Arvid G Hogbom in his 1895 paper on carbon cycles put forward this theory:

8 Carbon dioxide can be considered to be supplied to the atmosphere chiefly through the following processes:
1) volcanic emissions, together with the following geological phenomena,
2) combustion within the higher air layers of carbonaceous meteors,
3) organic substances burning and decaying,
4) decomposition of carbonate rocks,
5) liberation of the carbon dioxide absorbed in sea-water as a result of temperature increase or reduction in atmospheric CO2 and partial pressure,
6) liberation of mechanically entrapped carbon dioxide in rocks when they decompose by weathering etc.



zebra | January 19, 2017 at 16:01

I agree with your proposed modification of the D-C-S model. I would also have to add that the 'trickle' should be a 'drip' to give a better visual 'quantitative' representation.

I think the next question is nicely summarised by James
james cobban | January 19, 2017 at 16:19
last paragraph.



Glad you agree.

But didn't I answer James' last paragraph in my 17:13 comment? We have to distinguish between transport, dilution, and sequestration.


zebra | January 19, 2017 at 17:13

"It is being diluted, but if you disregard the sequestering processes, in the end you will still be somewhere above pre-industrial."

Zebra, unfortunately the sequestration cannot be ignored; that is the only part of the process that takes atmosheric CO2 out of the equation. If it is not sequestrated it returns to the top office to re-enter the atmosphere.

This is the point that so concerns James.


james cobban | January 19, 2017 at 16:19

Absolutely correct James.

This IS the critic point. It is the point that I have been trying to get across throughout the debate but unfortunately you are the only person who seems to have recognized this critical distinction; whether you agree with one side of the debate or the other, I think, so far as you are concerned 'the jury is still out'.



"that is the only part of the process that takes atmospheric CO2 out of the equation. "

I thought that's what I said.

I think you may have a problem with conflating time-scales, though. Even without sequestration, in the longer term, there would be dilution, meaning that atmospheric CO2-- which is what we care about for the warming issue-- will in fact be reduced. The exchange between deep water and atmosphere slows things down, but in the end a new equilibrium will be reached. Maybe that 17% Pieter Tans suggests as a first approximation for the atmosphere? So if we double CO2, we get 280ppm plus (.17 times 280) at some point in the future.

That would be OK if it happens in a reasonable time. But again, what that time will be is what the debate is.

Bill Fothergill

Response No 2: From Ralph Keeling at the Scripps Institution in San Diego

(NB There are some parts of Professor Keeling's response which I have redacted. He has asked me to participate in the testing of a small piece of software, and the redacted sections relate entirely to that. The software is being kept out of the public domain until a time of Prof Keeling's choosing.)


I'm responding here via my gmail account because of a bouncing problem (see below).

I don't have time now to read the blog thread, but I appreciate the interest. The topic of how the sinks respond to emissions has subtleties and prone to being confused, even by very thoughtful people. The sinks respond to emissions only through the atmospheric loading, confirming one of the viewpoints. But there are still subtleties. I'm attaching a spreadsheet I've created for teaching purposes which calculates atmospheric growth versus emissions and which exposes most of the subtleties.

... REDACTED ...

A good exercise is to play around with typing new numbers in the orange squares to try to get atmospheric CO2 to stabilize at, say current levels. You will find that doing this requires that emissions be cut promptly by ~ 50% and then slowly cut further after that. Stabilization requires that the sources equal the sinks. The ~50% cut is required because the sinks currently absorb about 50% of emissions, and they CONTINUE to operate even after the emissions are cut because they respond to the atmospheric loading, not the emissions themselves.

In time, however, the sinks start to saturate, and take up less carbon, even while the atmospheric level stays constant. The allowed emissions therefore also decrease over time in order to not exceed the sinks. It's also useful to construct a stabilization scenario for a higher level, e.g. say 450 ppm. In that case, emissions can continue to rise for a while. But once you get close to the 450 threshold, you still need a ~50% cut with further cuts after that. Same logic.

... REDACTED ...

The spreadsheet doesn't address feedbacks of climate change on CO2 (e.g. CO2 release from warming tundra, changes in Henry's law with temperature, or changes in ocean circulation impacting the ocean sink). Many of these are still subject of ongoing research and not ready to be folded into such a simple model. They are likely to cause the spreadsheet to underestimate future rises, probably at a level similar to the seawater non-linearity issue. But the big driver of future CO2 rise is fossil-fuel burning, which is captured in this spreadsheet.

I hope this helps.


Bill Fothergill

Response No 3: From David Archer at the University of Chicago

"Hello Bill,

... Brief personal banter - redacted ...

I had a similar question a week or so ago; how much CO2 would we have to pull out of the atmosphere to reach 350 in a couple of decades? I used an on-line simplified carbon cycle / climate model called ISAM that I made a web interface for, at http://climatemodels.uchicago.edu/isam/ . The interface allows you to alter the CO2 emissions through time in the future and see atmospheric CO2, temperature, etc. It’s a simplified model but has been tuned to reproduce the results of more mechanistically realistic models. The answer is to get to 350 you have to take out the excess in the air, and some more that the ocean helpfully degasses as it tries to buffer atmospheric CO2 concentration.

So a screen shot of the model with CO2 emissions stopping at 2025 is here. You can see CO2 dropping slowly over the rest of the century, reaching about 380 by 2100. I set the bottom plot to show the carbon fluxes, and what is says is that the ocean continues to take up CO2 but at a reduced rate after it starts heading down.

Without a model, I’d have guessed that your idea #2 would have been right, but the model says the #1 people got it right.

I hope this helps restore harmony in your on-line community!


NOTE: In my email to David Archer, I outlined the two conflicting viewpoints as follows...

"The nub of the matter appears to revolve around how Henry's Law will affect oceanic carbon uptake. One side of the debate thinks that the current "high" atmospheric CO2 concentration will continue to drive CO2 into the oceans - albeit at a gradually decreasing rate - even if emissions were to cease altogether.

The other side maintains that it is only the fact that atmospheric concentrations are rising (at ~ 2ppm per annum) that is responsible for the continuing oceanic uptake. Consequently, if emissions ceased, this oceanic uptake would cease shortly thereafter because the atmospheric and dissolved CO2 partial pressures would basically rapidly attain equilibrium."

Therefore, when David refers to "idea#1", this means the viewpoint mentioned first in my original email. In other words, the viewpoint espoused by, amongst others, Rob Dekker and Michael Sweet.

The second viewpoint covered in my original email would therefore correspond to "idea#2" - the view held by, amongst others, D_C_S and D-Penguin.

Although "Henry's Law" was not explicitly mentioned in the ongoing debate (if it was, and I missed it, I apologise profusely) it seemed clear to me that it was differing perceptions as to the rate at which partial pressures (in the air and in the ocean) were changing - relative to each other - that was leading to the polarisation of viewpoints. Hence my reference to Henry's Law.

Note that David admitted his "gut feel" was at odds with what his model ended up telling him. This serves to reinforce the point that Ralph Keeling made regarding the subtleties at play here.

Bill Fothergill

After I had sent "thank you" emails to Pieter, Ralph and David, Pieter added the following observation...

" Bill,

I should have added after my comment about "decreased calcification rates by organisms" that this effect is likely to be an ecological disaster. In conjunction with warmer ocean surface temperatures it implies severe damage to most coral reefs, as well as many calcium shell building organisms at the base of the ocean food chain. The added CO2 eventually becoming a part of sea salt would be way too late to prevent a disaster.

Best regards,


zebra | January 19, 2017 at 21:55


I apologize about the confussion, my fault.

It was this part of James' comment, in his last paragraph, that I was referring to:-

1. "...ocean-bottom sediment formation, which removes only an INSIGNIFICANT amount of CO2 each year, and surface-to-deep-ocean mixing, which perhaps transports relatively large amounts of CO2 to the deep ocean layers each year?
(My capitals)

In his pen-ultimate paragraph James observed that:-

2. "It's an important point since it would seem to add more than a touch of hopelessness to our situation if we cannot count on the oceans to quickly draw down the atmospheric CO2 after we stop emitting."

It is my opinion that debate leading from 2. would lead to some progress (hopefully).


Wow was this a great thread.
Thank you Bill F. for that!!!


zebra | January 19, 2017 at 21:55


The point that I am trying to make is that IF you take sequestration out of the CO2 circulation path through the ocean it is nearly all returned to the atmosphere (there are caveats) but this is the principle of the issue.

Then, the next point on in the debate would be; with less CO2 in the atmosphere, the Atmospheric/Oceanic CO2 flux presently -ve, tends to equilibrium and then to +ve with more CO2 being emitted from the oceans than absorbed by the oceans.

To me it appears that this is the point on which opinions on this blog thread diverge.



I think the input from the experts (great job Bill F) serves to validate what I have said all along, which is that pinning down the rate of atmospheric CO2 reduction is still a work in progress-- for them, much less those of us who aren't working at that level.

So, I have only been trying to clarify what is happening at a conceptual and "first approximation" level, so perhaps different "opinions" will at least be working from the same fundamental principles and terminology.

I suggest you look at the reference I gave, figure 7. This shows the pre-industrial distribution of C vertically as well as across basins. You seem to not understand that there was an equilibrium state reached somehow in the first place. This happened with all the same mechanisms-- like upwelling-- operating. It can't be the case that "more CO2 was being emitted than absorbed by the oceans", right?

So why would you think it would be happening when the future equilibrium is reached? It is obviously a contradiction in terms; by definition equilibrium means there is a balance.

I repeat my "diagnosis", which is that you are getting confused by the time periods involved. There will be periods where ocean to atmosphere transfers may affect things, but in the long term, dilution (even without sequestration) will result in lower atmospheric levels. Dilution means all the carbon is spread out between atmosphere, surface waters, and deep waters, so atmosphere will have less.


Bill Fothergill | January 19, 2017 at 22:45

"I hope this helps restore harmony in your on-line community!"

Broad grin and big chuckle!

Was there ever any dis-harmony?
No, we are all grown-up boys, exasperation er, well...yes.

Bill, nobody could call into question your work ethic and honest endevours, that I for one do not doubt and applaud. What a great idea to refer opposing views to the 'higher authorities'. It could become part of Blog 'due process', when opposing opinions develop, each side of the opinion agree on a statement to represent their respective viewpoint and then asked our learned friends to comment. NOT with the purpose of 'I'm right and you're wrong' but simply to help develop understanding for all.

Bill, please consider my responses to the replies you received:
- I entirely agree with the 'Side 1 View' that you presented and the responses.
- I did not agree with the response to the 'Side 2 View'
Not 'sour grapes', you simply mis-represented the Side 2 View (or at least my view, I cannot answer for D_C_S or others). I am certain that you presented the Side 2 View in good faith, I have no doubt about that.

So, there must be something missing and it is the missing something that I presently disagree with that leads Side 1 to the conclusion that, after emission cuts, the ocean will do the rest.

The bit that is 'missing' is what happens between the atmospheric CO2 being absorbed at the surface ocean and emitted from the surface ocean back into the atmosphere.

I really do not think that there is a disagreement about the 'absorbtion' side, its the 'emissions' side that I have an issue with.

Bill, I hope to God that you are right and I am wrong. If it is the other way round, it will take an effort on a Galactic scale to put right what we have all done wrong in the abuse of what is 'home' for all of us, Planet Earth.


zebra | January 20, 2017 at 00:22


The numbers refer to your paragraphs.
1. - Please refer to my comment addressed to Bill regarding the input from the experts.
- Not sure why you seem to imply that pinning down carbon levels somehow contradicts my opinion.
2. - That is exactly what I have been trying to do since this thread started - good luck.
3. - I always look at the links posted on comments and usually read the relevant part of the paper they refer to. When I looked at your link I recognised it from about 10 years ago, long before I signed up for Neven's Blog; along with what must be dozens of others much more recent than 2001 (date of your published Fig. if I remember correctly). Out of all the Global Carbon Cycle Figs. I have seen, I think the best presented one to aid this debate, was from an article published by the IPCC that I provided the link for in a previous comment. If anybody bothered to look I do not know.
- What would stop the Atmospheric/Oceanic CO2 flux changing from -ve to neutral to +ve? When pCO2 in the oceans increases and becomes greater than the pCO2 in the atmosphere, out pops a CO2 molecule; there are 37,200 Gt of them down there churning away and only about 920 Gt in the surface ocean, so still plenty of room for everybody being transported upwards towards the surface ocean by the thermal pump, ok, some of them lose their way and go sideways and a very, very few poor souls get caught by mother gravity and eventually sink to the ocean bed, in a calcified state and doomed never free to fly again in the sky for eons of years.
4. Same as 3. That one was easy.
5. Please look at the Fig. I provided the link for. There is another link that gives a more detailed picture of the various components to the diluted bits and what happens to them. Not sure if I linked that one.

All intended as a bit of humour to try and get a few ideas across, not at all intended as flippancy. Hope Neven doesn't censor me :).

Rob Dekker

Bill, thank you so much for consulting the experts on this, and reporting back to us their response. And if they read this blog thread, a big thank you to Pieter Tans, Ralph Keeling and David Archer for their valued insights.

Personally, I find Archer's interactive model the most interesting of the responses. It allows us to play with the parameters and see how atmospheric CO2 responds :

I trust that this model implementation settles the disputes on this thread about what happens when we cut emissions in half, and what happens when we cut emissions altogether today.



You misinterpreted my first paragraph.

I am not trying to take sides, but I am trying to correct what I see as a misconception on your part (your #3). If you are willing to address my simple scenarios, perhaps it will help. This is how many problems in physics have been resolved.

Say we have an initial condition where there is no CO2 at all, but all the mechanical processes operate-- evaporation and rainfall, ocean currents up and down, mixing by turbulence, and so on. Also, there are no lifeforms to sequester carbon, nor any interactions with rocks, and so on.

All that can happen is the "solution" process by which CO2 in water becomes various ions, as shown in the first figure of my reference, and of course the transport of CO2 molecules across the air-water interface.

Now, tell me what happens if

a) We introduce a charge of CO2 into the atmosphere.


b) We introduce a charge of CO2 into the ocean.

I say that in both cases we will eventually reach an equilibrium where molecules crossing the boundary in either direction will be about equal.

Please explain why you think this is not correct.

Bill Fothergill

"I hope this helps restore harmony in your on-line community!"

Broad grin and big chuckle!

Personally I think we all owe yet another big vote of thanks to Neven for providing a platform in which differing views can be discussed/debated in such a fashion.

I know that, yet again, I have been forced to think more deeply about a subject that would otherwise have happened. (When I say "deeply", I only mean by my own limited standards.)


zebra | January 20, 2017 at 14:01


A very appropriate response. I thoroughly support the Scientific Method.

Answers - Assuming conditions are no loss of CO2 made available to the surface water

a) The water will 'absorb' the available CO2 from the air at a decreasing rate until:
pCO2(air) = pCO2(water) BALANCED STATE

b) The air will 'absorb' the available CO2 from the water at a decreasing rate until:
pCO2(water) = pCO2(air) BALANCED STATE

Henry's Law applies in both cases a) and b)

Now, could you please tell me what happens when you go to the next step of the process, under the same conditions, when

c) We introduce a continuous and increasing supply of CO2 into the atmosphere
d) We introduce a continuous and increasing supply of CO2 into the ocean
e) What is the relationship between c) and if any?


Bill Fothergill | January 20, 2017 at 17:43

Indeed, many thanks to Neven for the opportunity. Well said.


zebra | January 20, 2017 at 14:01

e) What is the relationship brtween c) and d), if any?


Personally I think we all owe yet another big vote of thanks to Neven for providing a platform in which differing views can be discussed/debated in such a fashion.

Where would this platform be if it weren't for these interesting, speculative and respectful conversations? Thanks back to all of you.

I wasn't able to follow the whole discussion, let alone form an opinion about the subject, but one thing's for sure: We need to reduce emissions as fast as we can, and at the same time start drawing CO2 from the atmosphere.

An old friend opened a new topic on the Forum to draw attention to a relatively new project, aimed at putting the carbon back in depleted soils while restoring ecosystems and building up biodiversity again: Ecosystem Restoration Cooperative

I want to look into it this weekend to see how serious/thorough it is, but the first impression is good.


I think that the response by Pieter Tans supports my position.

Ralph Keeling and David Archer don't seem to answer the question specifically and directly. Neither of them mention emissions being "halved suddenly" as Pieter Tans does.

I agree with D-Penguin that my position was not presented entirely accurately in the email.

In any event, I don't see a need for further debate, at least on my part. The scenario probably won't happen anyways. Hopefully it does.



I think you meant to say "the Socratic Method", which is correct, but you will have to be patient because... I'm Socrates here!

Seriously, bear with me and go step by step.

So now, starting from equilibrium, we add another charge to either the air or the water.

Again, I say this will simply lead to a new equilibrium-- if we add it to the air, molecules will move to the water, and vice versa.


james cobban

Bill F, let me add my thanks to you for sending that email to Pieter Tans, David Archer, and Ralph Keeling. I think it speaks volumes to your character that all three scientists replied to you so quickly, and in such detail. It also speaks volumes of Neven's blog that such communication can take place between concerned citizens and the scientific community, and at a level that doesn't require the scientists to dumb it down. Where else but this blog can that happen?


zebra | January 20, 2017 at 20:20


Ok, short step by short step it is, I am sure will will get there eventually.



zebra | January 20, 2017 at 20:20


The following links will help, with agreed terminology and process identification, as the Q&A sessions progress

Climate Change 2007: Working Group I: The Physical Science Basis
Physical Science Basis

It would be interesting to seperately discuss the implications of the Figures in the links anyway. I think that eventually the Q&A sessions will lead to that discussion taking place...but I'll leave the decision on that one to Socrates!

Rob Dekker

zebra said

I think the input from the experts (great job Bill F) serves to validate what I have said all along, which is that pinning down the rate of atmospheric CO2 reduction is still a work in progress-- for them, much less those of us who aren't working at that level.

Not really.
The big boys had this all figured out already. For example : Hansen et al 2013 :
Look at figure 4, where the result is shown for cutting emissions at various times. See the steep decline after we stop emitting ? And how it levels off after centuries ? That is the ocean absorbing our past emissions. First quickly and then slower as our carbon ends up deeper and deeper into the oceans, and the air-ocean system obtains a new equilibrium.

And figure 5 in the same paper shows the result of what happens when we not immediately stop emitting, but instead lower emission by some set amount per year. The same effect of peak and then decline caused by oceans absorbing our past emissions is apparent.

And note that just a decade or two of WAITING (not acting) has a profound effect on the final equilibrium CO2 level that the planet will level off to as the oceans mix our carbon over the centuries ahead. Waiting right now makes it much harder for future generations to clean up the mess we are making right now.

Of course we could have used these figures during our argument, but it would have been sort of an appeal to authority. That is why I appreciate the discussion we had here, and I hope that the discussion did increase understanding of the way that our planet responds to our insanely fast pulse of CO2 into the atmosphere, and what will happen in the future once we start cutting emissions.

Just to show what happened with the carbon we emitted over the past century as it was absorbed by the oceans, here is an image from the article that zebra posted before showing where our carbon went in the oceans :

Note that the deep ocean (tank 3 in DCS analogy) is still in in its pre-industrial state, with plenty of space to mix carbon thoroughly in the decades and centuries ahead.
This is the reason why atmospheric CO2 levels will go down after we reduce/stop emitting.

As I stated before : The oceans (and the terrestrial biosphere) are trying everything they can, but they need a break to restore the damage we are doing by so rapidly dumping CO2 into the atmosphere.

Rob Dekker

Correction: "restore the damage" should read as "fix some of the damage".



Sorry, you are right that this goes too slow when real life interrupts the typing. But really there is only one more point to establish, and I will just assume that you will agree:

Since the system always goes to equilibrium, we can always detect an imbalance by measuring either side-- if there is excess in the water, we will see the concentration rising in the air, and vice versa. OK? Given that...

We have data that CO2 in the atmosphere was relatively constant for, say, the last 10K years, until we clever monkeys messed things up. That means the system, with all the same transport and mixing mechanisms operating, was in equilibrium.

Then, assuming we "stop today", humans added a charge of CO2 to the atmosphere. It doesn't matter that it took 150 years; as others have pointed out, that's a very short time relatively speaking given the size of the charge.

So now you get to explain your reasoning why the system doesn't just go to equilibrium. (Remember, we're putting aside any of the other effects like biological sequestration.)

I don't see how any other outcome is possible.


Rob Dekker,

There's pinning down and then there's pinning down... I am not familiar with how much consensus there is among those big dogs, and I thought the responses to Bill indicated considerable uncertainty.

But really the point I was trying to make was that the best those of us without complex models and supercomputers can do is get the descriptive physics right and maybe up/down, big/small, kinds of first approximations.

If I recall, the two "sides" started out trying to reach quantitative conclusions by just quoting particular sentences from some papers, which is kind of appeal-to-authority lite, maybe?

In the end, my best guess probably agrees with your assessment as I said to James: If we were to "end FF use" in 100 years, things would be OK in the long term, with some disruption. But, I strongly maintain that it is just a guess.


zebra | January 21, 2017 at 12:48


Your Paras. 1,2 and 3 - AGREED

Para. 4. This is important. The system has moved from what was to all intents and purposes a constant state to a dynamic state. I think you will agree.

Para. 5. Fair point and I accept the constraints.

"I don't see how any other outcome is possible."

I AGREE with the statement but what is the outcome that you are referring to? This is the point of divergence. Please read on...

I will enumerate the stages of the Model so that you can AGREE or DISAGREE (Socrates is back).

1. In a dynamic system between the atmosphere and oceans at the surface ocean the Atmospheric/Oceanic CO2 flux always tends to a balanced state.

2. The Atmospheric/Oceanic CO2 flux at the surface ocean can be -v, 0 or +ve.

3. pCO2(atm) and pCO2(ocn) represent the molecular pressures where pCO2(atm) is constant and pCO2(ocn) is variable at the surface ocean (a consequence of the dynamic system).

4. When the concentration levels of atmospheric CO2 continue to increase, the flux at the surface ocean becomes increasingly -ve (a consequence of the fact that the oceans have a capacity to absorb CO2 to a limit that tends towards infinity). Therefore, the oceans absorbtion of CO2 increase and emissions of CO2 increase as the system strives to achieve a balanced state.
pCO2(atm) > pCO2(ocn) -ve flux

5. When the concentration levels of atmospheric CO2 cease to increase, the flux at the surface ocean becomes decreasingly -ve. Therefore, the oceans absorbtion of CO2 decrease and emissions of CO2 INCREASE in relative terms as the system strives to achieve a balanced state.
pCO2(atm) > pCO2(ocn) -ve flux (but reducing)

6. The balanced state occurs approximately 10 years after the concentration levels of atmospheric CO2 cease to increase (this is the approximate time period of the absorbtion and emission cycle).
pCO2(atm) = pCO2(ocn) 0 flux
followed by
pCO2(atm) < pCO2(ocn) +ve flux
and then
pCO2(atm) = pCo2(ocn) 0 flux again

7. In the balanced state at the surface ocean atmospheric CO2 absorbtion will continue and oceanic CO2 emissions will continue (with a time lag. See point 6.) to maintain the balanced state of 0 flux.

8. In the balanced state the oceans can not continue to remove atmosperic CO2 at a rate that exceeds the oceans rate of emission of CO2 that is returned back into the atmosphere.

9. In the balanced state the oceans will play no part in further reduction of atmospheric CO2 without intervention.

I have set out a Simple Climate Model, in the real world there are caveats but I agreed to accept your constraints and this was fair. The caveats finesse the Model but do not change the principles.

If there is agreement on each stage of the Model, then that is the beginning of the debate, what follows determines the fate of the planet.


This looks looks like a 'straight forward' chemical engineering problem. Unfortunately, there are many aspects to the problem that are less well understood than desirable. E.g. mixing with depth, temperature, pH, etc... Looks are often deceptive.

You can think of this as akin to a standard problem assigned in chemical engineering classes - producing a five compartment model of blood and kidney function. That problem is easy by comparison. Blood in the tissues, blood in circulation, blood in the brain, blood in the lungs, blood in the liver, and blood in the kidneys are easily defined. So too are the interactions among these with mass transfers from one to another, and with fairly well defined parameters for various inputs from the air across the lung surface, through ingestion and out through excretion and urine.

This problem by comparison is vastly more complex. The tendency is to treat it as a computational fluid dynamics problem with the oceans broken into gridded layers by depth, latitude and longitude, and the same for the atmosphere.

That can work if the problem is setup sufficiently well with the necessary concentrations and interactions. However, the grid spacing with depth and across the surface has to be sufficiently fine to adequately capture the dynamics. And the time slices have to be defined based on the grid spacing so as not to result in absurdities in the calculations.

Then too there is the little problem of dynamic instability in the fluid flows that may necessitate even finer grid spacing and lead to greater uncertainties. Non-dimensional analysis and tests can go a long way toward warning when certain condition boundaries are approached or crossed, or when the behavior is likely to change in fundamental ways.

It doesn't take too long in pursuing this to realize that to do the problem well requires computational power greater than the entire computational power of all human devices taken together a century from now.

So what do? -> simplify. That risks missing major issues, but allows for computationally doable problem development and answers in reasonable time.

And this is precisely what has been done. But that begs the question of how well we understand the details of the systems and how well we have captured the interactions.

The next easier step is to do even courser correlative analysis and treat the problem as a summation of other problems (akin to what you all are discussing here). Then with those sufficiently defined, a course assemblage model can be developed that can be run on light duty computers (laptops even). This is of course at the expense of rigor. The World 3 model from the club of Rome is an example of this.

These do allow for a better understanding of the whoop and wow of the system. They might give us some idea about the stiffness of the problem and the likelihood that we will get kicked int he collective rears by that.

Stiff equations by the way, are equations in complex dynamical system that resist movement for long periods, then suddenly respond catastrophically. These tend to be driven by partial differential equations with tanking functions where some input accumulates until it overcomes some often undefined resistance, or result in a state transit in the system. The equations sometimes reveal this from simple analysis. Sometimes they don't.

The simple cases can often then can be thought of in terms of Rene Thom's Theorie' de la Catastrophe. In visual terms, the equation space is a multidimensional folded sheet. Movement across the sheet can encounter sudden transitions to other parts of the sheet. Reversal does not then reverse the transition. (Think hysteresis).

I applaud your efforts to think through these dynamics. It is useful.

I do encourage caution though in believing at any point that you have (any of us) captured all of the important or controlling aspects.



Sam | January 22, 2017 at 00:27


Great comments and fully appreciated.

The simple Model I produced was part of a discussion between Zebra and myself. Zebra suggested that a simple model free of all the advanced climate model caveats could be helpful in advancing the debate. I made reference to the omission of the caveats at the beginning and end of my comment, perhaps you missed that bit.

However, I also said that the caveats do not change the principles of the Model but do finesse events that should be incorporated into the model.

The points that you quite properly raised would then have become the next part of the discussion in the debate.

I think that your points are nicely addressed by:-


The effects of buffer and temperature feedback on the oceanic uptake of CO2

Chuixiang Yi, Peng Gong, Ming Xu and Ye Qi
Department of ESPM, University of California, Berkeley, USA"

It is a short letter, only three pages, excluding the References Section.


What particularly interested me were the Model parameters. The Calculus in the differential equations was well presented with easy cross-reference to the parameters.

It would be very interesting to read your comments regarding the controlling aspects in particular and the mathematics.


Sam | January 22, 2017 at 00:27


Also a usefull Figure that, I think, does cover the important or controlling factors is by Prentice, I.C. et al

Immediate Climate change 2001: the scientific basis: contribution of Working Group I to the Third Assessment Report of the Intergouvernmental Panel on Climate Change / Houghton, J.T. [edit.] . - Cambridge : Cambridge University Press, 2001 . - p. 183-237


Again, interested to hear your views.


Rob Dekker | January 21, 2017 at 05:33


The Figures in the link that you provided correctly represent the analysis of the reaserch paper. I do not beleive that they represent what you think they represent. The metrics and framework reference of the work is clearly explained in the section:-

Carbon Cycle and Atmospheric CO2 - Page 10

Rob Dekker

zebra said

I am not familiar with how much consensus there is among those big dogs, and I thought the responses to Bill indicated considerable uncertainty.

In this thread, Bill presented responses from the experts Pieter Tans, Ralph Keeling and David Archer. I thought their response was pretty consistent regarding the question of what happens if we cut emissions today.

Which "considerable uncertainty" are you talking about ?

Rob Dekker

D-Penquin said

I do not beleive that they represent what you think they represent.

What do you believe they represent and what do you believe that I think they represent ?


D-Penguin and Rob Dekker,

Sam says it all, far better than I could.

My final suggestion is that you will reach a better understanding if you stay within the bounds of whoop and wow.

So, carry on, and thanks. Quite a relief from trying to deal with Denialists who simply reject all physics and quantitative reasoning.

Bill Fothergill

Sam certainly did provide some very concrete examples. At a more generic level, much of the complexity can be captured when one whispers the ghoulish term "Navier Stokes Equations". To the uninitiated, these can be simply described as a set of equations which describe fluid flows.


For those of us who used (misused? abused?) them at university, they probably still haunt our darkest nightmares.

Some of you are possibly aware that the Clay Mathematics Institute set seven "Millennium Problems", in a hope that this would serve to spur on research into certain seemingly intractable reaches of mathematics. Two of these are probably relatively well known, even to non-mathematicians - the Riemann Hypothesis and the Poincare Conjecture. However, nestled amongst these Seven Deadly Sins is, you got it, The Navier Stokes.


michael sweet


In your model it appears to me that you have left out the transport of CO2 into the deep ocean. This occurs in the Arctic and Antarctic when deep water forms. This is the primary long term storage of CO2 in the ocean. Since the deep water circulation takes 1-2,000 years, it will be 1-2,000 years before the ocean reaches a new equilibrium.

This is discussed in the peer reviewed literature. How can you begin a discussion of ocean CO2 when you leave out the primary long term method of sequestration from the start? Where did you get your estimate of 10 years to a new equilibrium?

Above two posters call referring to the peer reviewed literature "appealing to authority". This completely turns the scientific method on its head. The literature vets arguments and tries to remove errors. If you do not reference your arguments to vetted studies you will repeat errors long ago corrected in the peer reviewed literature. Since scientists argue both sides of most issues, the literature can be cited by both sides.

Lack of reference to peer reviewed literature is the problem on "skeptical" sites. You have the same problem here if you do not reference the literature. Read Tom Curtis on Skeptical Science. Read Real Climate. The scientists on Real Climate always refer to the literature in any post they make, even though they are expert at what they write on. Amateurs need to provide a basis for their arguments. That lies in the peer reviewed literature. If you cannot find support for your argument in the literature that generally means that there is something incorrect in your argument.

You are reinventing the wheel with your discussions of ocean sequestration of CO2. Read the peer reviewed literature.


Rob Dekker | January 22, 2017 at 08:12


Your link:

Page 10 - Section:
Carbon Cycle and Atmospheric CO2

Direct Quote:
"...but it omits climate-carbon feedbacks, e.g., assuming
static global climate and ocean circulation."

So, you are looking at the Graph of a Static Model that presents differently to a Dynamic Model.

Direct Quote:
"Therefore our results should be regarded as conservative, especially for scenarios with large emissions."

This qualification, about the results, speaks volumes about the current research work brilliantly undertaken by the scientists at the behest of the IPCC.

This qualification of their work, by the authors themselves, is a massive understatement (typical of the scientific community) and reads as an iniquitous short sentence hidden away somewhere in another scientific paper.

Your position follows the Static Model and my position follows the dynamic model.

You might ask yourself why the research work follows the Static Model. You will find the answer in the IPC Metrics and Baseline Reference Frameworks presented to the scientific community.

You might ask yourself why the IPCC have, within the past three months, made a 180 deg turn on the Metrics and Baseline
Reference Frameworks.

You might ask yourself why the scientists are concerned that the new conditions for submission of new papers is November 2017; this is a process that usually takes up to four years. The scientists say they welcome the challenge (good luck).

The scientists have to submit abstracts and wait for approval (usually four months); apply for funding (usually four months); do the research (how long?); submit for peer review (how long?) then submit to IPCC by November this year.

I have tried to answer your question and if you disagree with my answer, point out where the disagreement lies, that is to 'debate'; referring me to another cherry picked graph without any reference to my response is not a 'debate', it is an attempt to re-inforce your opinion.


Hi. A very good reference for land and ocean uptake for anthropogenic CO2 is ar5 biogeochemistry chapter 6. It seems take Rob Dekker is correct inasmuch as if all anthropogenic carbon emissions were to cease, Atmospheric CO2 would decrease at about 2ppm initially. https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter06_FINAL.pdf


zebra | January 21, 2017 at 12:48


I explained. Presumably Socrates has grown weary and retired.

Conclusion of Debate:
Probably best not to continue debate because of high level of uncertainties.


michael sweet | January 22, 2017 at 14:42


Before you start telling me what I should do, why do you not practice what you preach? Read the posting properly before you comment.

Stop trying to teach your Grandmother how to suck eggs, it is very presumptuous of you.


SimonF | January 22, 2017 at 19:26


What is the difference to the link I posted, on three or four different occassions, apart from decadel reference
"Atmospheric CO2 would decrease at about 2ppm initially"
What part of Chapter 6 please?

Rob Dekker

D-Penquin said

Your position follows the Static Model and my position follows the dynamic model.

No D-Penquin, your model does not include ANY carbon feedbacks, so it's not dynamic. In fact, your model excludes the largest carbon storage tank on this planet : the deep ocean.

So your model is bunk.

Rob Dekker

D-Penquin, Hansen et al 2013 states explicitly :

We use the dynamic-sink pulseresponse
function version of the well-tested Bern carbon cycle
model [169], as described elsewhere [54,170].

How is your model better than the Bern carbon cycle model ?


D Peguin. Graphs on p473. It is so interesting that any reduction in first twenty years is quite big and if we were to cease all emissions now, we would be at the well advertised of CO2 safe level of 350ppm really quickly.

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