Effect of CO2 levels on phytoplankton.
Story submitted by Don Healy
This article opens up a whole new vista into the relationship between CO2 levels, oceanic plant growth and the complex relationships that we have yet to learn about in the field of climate science. If phytoplankton respond like most plant species do, we may find that the modest increases in CO2 levels we have experienced over the last 50 years may actually create a bounty of micro plant growth in the oceans, which would in turn create the food supply necessary to support an increase in the oceans’ animal population.
At the same time, it would explain where the excess atmospheric CO2 has been going; much of it converted into additional biological matter, with only a limited existence as raw CO2.
There may well be a naturally balancing mechanism that explains how the earth was able to survive atmospheric levels of CO2 as high as 7000 mmp in past geologic history without turning into another Venus. Just surmising of course, but this fits with what we know about the response of terrestrial plants to elevated CO2 levels, so it is a plausible theory. Hopefully more studies along this line can clarify the situation.
From the article:
The diatom blooming process is described in the article by Amala Mahadevan, the author of the study and oceanographer at WHOI, as inextricably linked to the flow of whirlpools circulating the plants through the water and keeping them afloat.
“[The study’s] results show that the bloom starts through eddies, even before the sun begins to warm the ocean,” said Ms. Mahadevan.
This study explains the causation of phytoplankton’s phenology—the reasons behind the annual timing of the microscopic plant’s natural cycle—as it is influenced by the ocean’s conditions.
“Springtime blooms of microscopic plants in the ocean absorb enormous quantities of carbon dioxide, much like our forests, emitting oxygen via photosynthesis. Their growth contributes to the oceanic uptake of carbon dioxide, amounting globally to about one-third of the carbon dioxide we put into the air each year through the burning of fossil fuels. An important question is how this ‘biological pump’ for carbon might change in the future as our climate evolves,” said researchers.
WHOI describes the study as being conducted by a specially designed robot that can float just below the surface like a phytoplankton (only much, much larger). Other robots, referred to by WHOI as “gliders” dove to depths of 1,000 meters to collect data and beam it back to shore. Together, the robots discovered a great deal about the biology and nature of the bloom. Then, using three-dimensional computer modeling to analyze the data, Ms. Mahadevan created a model that corresponded with observation of the natural phenomena.
Full story:
http://www.thebunsenburner.com/news/cause-of-north-atlantic-plankton-bloom-is-finally-revealed/
==================================================================
Eddy-Driven Stratification Initiates North Atlantic Spring Phytoplankton Blooms
Abstract
Springtime phytoplankton blooms photosynthetically fix carbon and export it from the surface ocean at globally important rates. These blooms are triggered by increased light exposure of the phytoplankton due to both seasonal light increase and the development of a near-surface vertical density gradient (stratification) that inhibits vertical mixing of the phytoplankton. Classically and in current climate models, that stratification is ascribed to a springtime warming of the sea surface. Here, using observations from the subpolar North Atlantic and a three-dimensional biophysical model, we show that the initial stratification and resulting bloom are instead caused by eddy-driven slumping of the basin-scale north-south density gradient, resulting in a patchy bloom beginning 20 to 30 days earlier than would occur by warming.
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Allan MacRae says:
July 19, 2012 at 9:52 pm
Sorry to hear of your travails, Allan. Not that it is likely to be any comfort, but few have escaped the recent economic tumult unscathed. And, your daughter is well. Not bad really, all things considered, in this crazy world.
Bart says:
July 20, 2012 at 12:30 am
Let us look at another approach:
In a closed system, given sufficient time, there is an equilibrium between the pCO2 of water at room temperature and the pCO2 of the air above it.
Then we replace some of the water at the bottom with an amount of colder water of the same composition, without affecting the temperature of the water-air surface. The pCO2 of the surface and the atmosphere thus remains the same. The pCO2 of the colder bottomwater anyway is lower than that at the surface. When that heats up to room temperature, the pCO2 of the bottomwater will reach exactly the same pCO2 as the surface water and the pCO2 of the air. Thus no extra flux is generated.
The difference is in an open system like the tropical upwelling, where the deep ocean waters are richer in CO2 than the surface waters, thus an increase in deep ocean upwelling will give an increase in CO2 releases. But the same increase in deep ocean circulation will give an increase in downwelling at the other side of the earth near the poles… Thus it depends of the unbalance between upwelling and downwelling. Which is more downwelling than upwelling…
Thus it depends of the unbalance between upwelling and downwelling. Which is more downwelling than upwelling…
Of course that is for the upwelling and downwelling of the amounts of CO2 dissolved in water, not about the amounts of water. Any unbalance in water up/downwelling would give a change in sealevel, which is not observed…
Allan MacRae says:
July 19, 2012 at 9:52 pm
Allan, while we disagree on the T or dT/dt point, I hope you will encounter better times in the near future, as life is already short enough…
Bart says:
July 20, 2012 at 12:30 am
Sorry, my reaction was not complete:
In the case of a continuous addition of CO2 enriched deep ocean waters, there is a continuous flow out of the sea surface at the upwelling places, depending of the seawater temperature and thus the pCO2 difference between the ocean surface and the atmosphere. The temperature dependency is about 16 microatm/°C. Thus with an increase of ~16 ppmv in the atmosphere, the extra flux falls back to zero. At the downwelling side, the same change in atmospheric pCO2 pushes more CO2 into the deep, which makes that an overall increase of ~8 ppmv is sufficient to compensate for an overall increase of 1°C of the ocean surface waters, including an enhanced CO2 circulation flow between the upwelling and downwelling places. The extra 8 ppmv is already reached with two years of human emissions (or 4 years minus the sink rate)… Thus still no continuous increase in CO2 levels in the atmosphere for an increase in temperature…
Bart says:
July 19, 2012 at 4:44 pm
If you did not perform moving averages on the temperature, then you did not compute dT/dt. The numerical derivative of T is very noisy, as one should expect, since the derivative operation amplifies high frequency noise. It looks like this.
Indeed it is very noisy, therefore I performed a moving average of the result. By using the monthly dT/dt, I introduce only 1/2 month fase shift, instead of 1/2 year, but also a lot of noise. The 12-month moving average of the result gives an extra shift of 6 months. But ultimately that is the result of the averaging, not of the process. For nature it doesn’t make much difference if the process in the first year of a change in temperature is time limited over 2-3 years or continuous. The difference between the two types of processes should be visible if the temperature remains constant over several years, but unfortunately there are no such periods in the past 50 years…
The 1992 Pinatubo eruption may be near such period, but that caused a different type of reaction: the scattering of sunlight by the ash in the stratosphere enhanced the photosynthesis by leaves which were normally hidden from direct sunlight for a part of the day. That reduced the CO2 increase rate below what was expected by the T or dT calculations…
fhhaynie says:
July 19, 2012 at 4:28 pm
Knowing the accumulation rate and anthropogenic emission rate does not make the natural input/output rate ratio constant as you must assume to make your mass balance work. I check my bank accounts each month and the accumulation rate is not constant. Both deposites and spenditures vary from month to month and the ratio is not constant and the longterm trend has been accumulation. Based on your model, you wouldn’t make a very good accountant.
Your reasoning is the other way out: what we observe is an increase in the atmosphere which is smaller than the human emissions. Thus whatever the inputs were and however they changed over the year(s) is not important for the mass balance. In all cases the sinks were larger than the sources over the past 50 years. With some small variations, but still more sink than source.
Any housewive with a houshold budget knows that if she adds 50 dollar in the morning into her wallet and at the end of the day, see finds an “increase” of 25 dollars, then she knows that all expenses and innings of the day were 25 dollar negative. No matter what the transfers during the day were, none of the other transfers is responsible for the “increase”.
Ferdinand,
“Thus whatever the inputs were and however they changed over the year(s) is not important for the mass balance. In all cases the sinks were larger than the sources over the past 50 years. With some small variations, but still more sink than source.” That statement is easily shown to be not true. If the sinks were greater than sources for the last 50 years, concentrations would have been falling. Your approach to “mass balance” assumes that because the accumelation rate is less than the anthropogenic emission rate, anthropogenic emissions are the sole cause and for your mass balance to work you postulate sinks greater than sources. I have shown you with my method of mass balance that there is a natural 200 year cycle change component in the accumulation data. That natural cycle accounts for most of the accumulation. The regression statistics includes both natural and anthropogenic and the R^2 are greater than 0.97. The resulting coefficients for both are highly significant with very narrow confidence limits. These results show your method to be flawed, but apparently, you are so vested in your method (that the IPPC uses) that you are not willing to accept it.
Ferdinand Engelbeen says:
July 20, 2012 at 2:36 am
“The pCO2 of the colder bottomwater anyway is lower than that at the surface.”
In my scenario, it isn’t. I have explicitly stated that the cold water I have introduced in has greater CO2.
For the Earth, the cold water downwells at the poles, and upwells in the tropics. The cold water naturally has greater CO2 content, but what matters is what is going out versus what is going in. So, what matters is the CO2 content of the cold water sinking at the poles versus the upwelling water in the tropics, which depends on the temperature of the upwelling water when it sank versus the temperature of the water currently downwelling at the poles.
“Thus it depends of the unbalance between upwelling and downwelling.”
Ah, I see now you got what I just stated. So, if the water currently upwelling sank at a time of colder temperatures than today, we should get a continuous pumping of CO2 into the atmosphere.
Ferdinand Engelbeen says:
July 20, 2012 at 3:53 am
If you do it correctly, you will get a phase mis-match such as I have shown. It is actually elementary. The fact that a derivative gives a 90 degree phase shift is well known. It is manifested obviously when you take the derivative of a sinusoidal term, e.g., d(sin(w*t))/dt = w*cos(w*t). The cosine leads the sine by 1/4 wavelength (90 degrees of phase).
fhhaynie says:
July 20, 2012 at 6:41 am
Dear Fred,
I was talking about the natural sinks larger than the natural sources. As long as no carbon is lost in space (which is very unlikely), we have a flexible mass balance:
increase in the atmosphere = human emissions + natural sources – natural sinks
of which two are known:
4 +/- 2 GtC/year = 8 GtC/year + natural releases – natural sinks
thus
natural sources – natural sinks = -4 +/- 2 GtC/year.
In all years since 1960, the natural sinks were larger than the natural sources:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em.jpg
with a temperature caused variability around the trend of +/- 1 ppmv (~2 GtC).
Except if you let disappear the human emissions in some black hole and replace it by a natural process that exactly mimics the human emissions in amount and isotopic ratio, that is the single cause of the increase in the atmosphere, besides a small contribution from temperature of maximum 8 ppmv since the LIA.
Other natural causes may have contributed in the variability in increase rate too, but the net result of all these natural contributions was more sink than source…
Of course, as the human emissions are quite monotonely slightly exponentially increasing over time, the resulting increase in the atmosphere can be fitted with some polynomial, but that does in no way prove that the increase is non-human…
Even the IPCC may have it sometimes right…
Bart says:
July 20, 2012 at 12:30 am
This is not a one shot deal. It is a repeating process in which a volume of lower CO2 warm water is replaced a like volume of higher CO2 cold water over and over again.
Sorry, overlooked this one this morning, was 3 AM here before going to sleep…
If you do that in a closed vessel in equilibrium between air and water with a certain CO2 content, then the CO2 enriched water will release some extra CO2 when warming up, thus increasing the pCO2 of the atmosphere. That process can be repeated, but the release of extra CO2 will reduce with each step, as the pCO2 of the atmospheric part is increasing. Ultimately a new equilibrium will be reached when all old liquid is replaced with the new liquid and no further release of CO2 from newly introduced cold water will occur at warming up to room temperature.
Ferdinand Engelbeen says:
July 20, 2012 at 11:17 am
“That process can be repeated, but the release of extra CO2 will reduce with each step, as the pCO2 of the atmospheric part is increasing. Ultimately a new equilibrium will be reached when all old liquid is replaced with the new liquid and no further release of CO2 from newly introduced cold water will occur at warming up to room temperature.”
Indeed. If you look back at my July 18, 2012 at 6:26 pm post, I specifically addressed this:
Thus,
And, it goes without saying that tau must be large, because that is what the data tells us is true.
Note the limit implied by
“dCO2/dt = -CO2 / tau + k * (T – To)”
The process stops when dCO2/dt = 0, which implies that CO2 asymptotically approaches tau*k*(T0To). But, along a timeline much less than tau, the equation approximately behaves as an integral without the -CO2 / tau term.
So, the question is, how long does it take for the process to stop, or deviate significantly from a straight integral? It takes as long as is necessary for the water downwelling at the poles to have the same CO2 content as the water upwelling in the tropics.
…CO2 asymptotically approaches tau*k*(T-To)“. Clumsy fingers.
“It takes as long as is necessary for the water downwelling at the poles to have the same CO2 content as the water upwelling in the tropics.”
And, the data tell us we’re not there yet.
Bart says:
July 20, 2012 at 1:01 pm
“It takes as long as is necessary for the water downwelling at the poles to have the same CO2 content as the water upwelling in the tropics.”
And, the data tell us we’re not there yet.
Except that the data show that the oceans are a net sink for CO2…
http://www.pmel.noaa.gov/pubs/outstand/feel2331/exchange.shtml
The average pCO2 of the global ocean is about 7 µatm lower than the atmosphere, which is the primary driving force for uptake by the ocean
The area weighted average fluxes calculated from the area delta pCO2 and wind speed show a net uptake:
http://www.pmel.noaa.gov/pubs/outstand/feel2331/mean.shtml
Fig. 6: This map yields an annual oceanic uptake flux for CO2 of 2.2 ± 0.4 Pg C/yr.
So, dream further that there is somewhere a permanent source of CO2 if you turn up the thermostat…
An average tells you little. What matters is the relative content of upwelling and downwelling THC.
But, ignore what the data are telling us if you like. Just don’t be shocked when everything you have convinced yourself to believe turns out to be wrong.
Wow. I wasn’t quite expecting such a long reply. *Groans at the thought of having to type-out a mini-essay*
“A 30% increase of CO2 in the atmosphere (+ 240 GtC to 1040 GtC) gives a corresponding 30% increase of free CO2 in seawater, per Henry’s Law.”
Sorry Ferdinand, but I don’t see how those figures you cited from the carbon-cycle show that the oceans are absorbing 30% of human-emitted CO2. I must say, I am struggling to follow the logic behind your arguments. As I understand, Henry’s law applies to all liquid, both sea-water and fresh-water. We know that on equilibrium the oceans must end up absorbing 98% of human-emitted CO2, as ordained by Henry’s law. This is exactly why there currently exists 50 times as much CO2 in the oceans than the atmosphere, because of Henry’s law. As far as I can tell, your argument is that the ‘equilibrium’ between atmospheric CO2 and DIC would take hundreds of years. I find this unlikely, due to the fact that the residence time of DIC in the surface-ocean is very short, meaning there can be no significant ‘bottle-neck’ as claimed by CAGW-alarmists. The residence time of 10 years for of DIC in the surface-ocean means that all CO2 in the surface-ocean (that includes anthropogenic CO2 too) can only remain there for 10 years, at the most before going down to the deep-ocean. Having considered your arguments (of those I could understand) I remain unconvinced.
“But lucky for us, seawater is a buffer, thus a lot more CO2 is dissociated than if it would have been fresh water: about 10% of the increase in the atmosphere, or 30 GtC. Thus after 2-3 years 10% of the increase in the atmosphere is absorbed by the ocean surface and there it stops.”
I have no idea what you’re saying here. Sorry, but trying to understand what you write is like trying to decipher ancient Egyptian hieroglyphics — crazy confusing.
“The ‘partitioning ratio’ of 1:50 says nothing about the ultimate distribution between the different compartiments: it is only a ratio of the current amounts.”
The 1:50 partitioning ratio states that on equilibrium 98% of any CO2 emitted into the atmosphere must be absorbed by the oceans. It’s that simple.
“Only the pressure differences between atmosphere and oceans (for the deep oceans at the sink and source places) counts, as that is the driving force for uptake and release, not quantities.”
And what happens when you increase the partial pressure of CO2 in the atmosphere? You create a disequilibrium in the 1:50 partitioning ratio and force more CO2 down to the oceans in order to restore equilibrium. The higher you increase the partial pressure the stronger the driving force of CO2 down to the oceans.
“In reality, what is fixed is pCO2(aq) for a fixed pCO2(atm)”
PCO2(aq) is not fixed by PCO2(atm). They are intereated and depedent on each-other. Increase PCO2(aq) and to restore equilibrium CO2 is forced into the atmosphere. Increase pCO2(atm) and CO2 is forced down to the oceans, with the amount being forced down being determined by the partitioning ratio.
“The Revelle factor has nothing to do with Henry’s Law. Henry’s Law says something about the ratio between pCO2(atm) and pCO2(aq). The Revelle factor says something about the ratio between a change in pCO2(aq) and the resulting change in DIC.”
As far as my limited-capacities are able to judge, the Revelle Factor is in total contradiction with Henry’s law. It’s rather simple to demonstrate this mathematically. For example, if we apply the Revelle Factor to water with low pH and low CO32 concentration, such as a carbonated-drink, the resulting value that we get for the Revelle Factor is ludicrously high. So high, making carbonated drinks would be a physical impossibility. As I have shown with the above calculation, the Revelle Factor applies to all water, more or less the same. The Revelle Factor is simply brought about by changes in the relative concentrations of DIC. I don’t understand why you would say that the Revelle Factor and Henry’s law are “independent of each-other”. Henry’s law gives us a fixed partitioning ratio between atmospheric CO2 and DIC and the Revelle Factor gives us a fixed partitioning ratio between atmospheric CO2 and DIC. Henry’s law gives us a fixed partitioning ratio of 1:50 whereas the Revelle Factor gives us a fixed partitioning ratio of 10:1. If they are independent of each-other then my name is Dancing Wizard Magicus Feeticus. Have you read Segalstad’s papers? He provides some lucid explanations.
“The same problem as always with “residence time”. The residence time is about how much is exchanged per year between the ocean surface and the deep oceans. That is about 10% per year. That doesn’t say anything about how much CO2 is removed out of the ocean surface into the deep oceans.”
*Brain melts* But.. it does. The IPCC say that the upper surface-ocean contains about 900 gigatonnes of carbon and the removal rate from the surface to the deep-ocean is about 90 gigatonnes/year. Therefore anthropogenic carbon can only accumulate in the upper surface-ocean for about 10 years before being transferred to the deep ocean. Furthermore, measurements of anthropogenic additions of nuclear-C14 produced through nuclear atmospheric testing in the 1950’s and 1960’s have revealed important information about the circulation-time of chemicals in the upper ocean. Measurements of nuclear-C14 show that the circulation for carbon in the upper ocean is between 10-20 years (Druffel, E.R.M; Williams 1990). The conclusion is simple and straightforward and I don’t see why you’re having such a hard time understanding it: all CO2 in the surface-ocean (be it natural or human) can only stay there for 10 years before being transferred down to the deep ocean. Therefore, there is no significant ‘bottle-neck’ blocking the circulation of CO2. Your claim of 100 years seems a massive exaggeration to me, and again, I am struggling to understand the logic behind your argument.
Sorry, that should read: “They are interrelated” not “intereated”.
BTW: You’ve said before that you’ve talked to Seglstad. Did you find any of his arguments convincing or worth consideration?
chipstero7 says:
July 20, 2012 at 6:45 pm
“…I am struggling to understand the logic behind your argument.”
The logic is that the outcome is predetermined: the rise in CO2 is due to humans. It is taken as axiomatic. However the physics must be tortured to support that conclusion, the result has to be right, because otherwise, there is no significant human attribution, and that violates the fundamental axiom.
Ferdinand Engelbeen says:
July 20, 2012 at 2:45 pm
Considering this further, the estimates are based on measurements of carbon ratios between the ocean and the atmosphere above it. An implicit assumption has been made that the situation is static, and the only exchanges are in line with static laws. But, in fact, what we have here is a transport phenomenon of dynamic flows, in which upper waters of the ocean are flowing to the poles and sinking to the depths, then upwelling again in the tropics.
Bart says:
July 20, 2012 at 3:24 pm
An average tells you little. What matters is the relative content of upwelling and downwelling THC.”
Look at the graphic here.The upwelling (blue to red) occurs most prominently in the middle of the Pacific, and off the horn of Africa. Where do you see the highest positive flux here?
Conversely, the downwelling occurs most prominently off the coast of Greenland, and below the tip of South American. And, these are the areas of minimum flux. Coincidence?
chipstero7 says:
July 20, 2012 at 6:45 pm
OK. I will try to make it as clear as can, step by step.
– The 1:50 ratio is the current ratio in carbon mass between the atmosphere and the oceans as a whole. It may that this will be the utimate ratio that will be reached in equilibrium, thus let us for the moment assume that this is what we will get after some time.
– The bulk of that carbon is in the deep oceans, which are quite isolated from the atmosphere by the “mixed layer”, which is in close contact with the atmosphere by wind and convection.
– The mixed layer rapidely gets in equilibrium with the atmosphere for CO2 levels, that process needs only 2-3 year for completion.
– The mixed layer contains ~1000 GtC, the atmosphere ~800 GtC, thus the ratio between these two is 1:1.25.
– Henry’s Law says that for a change in pCO2 in the atmosphere, the same change in pCO2 in water must follow (and reverse). But that is not a fixed ratio between pCO2(atm) and DIC, as you think, it is about a fixed ratio between CO2(atm) and free, gaseous, CO2 in water, whatever the concentrations of HCO3- and CO3–. Henry’s Law only considers the solubility of the same gas species between atmosphere and a liquid, not any other species in solution. There is no direct pCO2 from bicarbonate or carbonate: you can dissolve any amount of (baking) soda until saturation, no CO2 will be released (except when heated for baking soda, as you change the equilibria), despite total carbon levels many times exceeding these of the atmosphere…
– Thus an increase of 30% (~100 ppmv or 210 GtC) in the atmosphere would give a fast increase of 30% in free CO2 in the mixed layer of the oceans, as that is what Henry’s Law says. But as the amount of free CO2 in the mixed layer is only 1% of all CO2 there, that means that the amount of free CO2 increases from 10 GtC to 13 GtC, not really a relief…
– But seawater is a buffer. That means that some of the increase of pCO2(aq) will further dissociate into bicarbonate and carbonate, depending of the pH. In fresh water that is only 3% (the Revelle factor here is only ~1.03). Thus the 13 GtC only increases to 13.4 GtC, hardly a difference, if the ocean surface was fresh water. In the case of seawater, the Revelle factor is ~10, thus a 30% increase in pCO2 of the atmosphere gives a 30% increase of free CO2 in the ocean surface and a 3% increase in total DIC. That gives a total increase of ~30 GtC in the ocean surface, compared to ~3.4 GtC if that was fresh water. Thus the Revelle factor is not a restraint for the uptake of CO2, it mainly shows how much more can be dissolved in seawater than in fresh water.
So that was the portion about Henry’s Law and the Revell factor. In summary:
Henry’s Law gives a fixed ratio between pCO2(atm) and pCO2(aq), where pCO2(aq) is only about free CO2, not bicarbonate or carbonate. The Revelle factor shows how much the total dissolved carbon changes for a change in pCO2(aq) and thus indrectly for pCO2(atm).
Now the removal rate:
– The exchange rate between the mixed layer and the deep oceans is 10% per year. If we increase the CO2 concentration in the atmosphere with 100%, that gives an increase of 10% in the mixed layer. The exchange rate remains the same, thus the new concentration with 10% more CO2 sinks in the deep and the old concentration comes back. That gives a 1% drop in concentration in the mixed layer, thus the new concentration now is 109%. The next year (if we for the moment may assume that no refilling from the atmosphere takes place) the drop is 0.9%, not 1% anymore, as the extra CO2 in the mixed layer is already reduced. Thus the concentration is reduced to 108.1%, the third year, the concentration drops to 107.3, etc… Thus the removal rate is much longer than the exchange rate, plus that the extra concentration in water is only 10% of that in the atmosphere. Thus to remove the extra 100% from the atmosphere, that takes many times longer than 10 years…
Measurements of nuclear-C14 show that the circulation for carbon in the upper ocean is between 10-20 years
You forget that the 14C in the atmosphere is extra fast thinned by the emissions of 14C-free CO2 from fossil fuel burning. Without that, the overall sink rate (ocean surface + deep oceans + vegetation) is ~4 GtC/year for an excess 210 GtC, that gives an e-fold rate of ~53 years or a ~40 years half life time for any isotopic form of CO2 in the atmosphere. In the ocean surface alone it is 2-3 years, but at a maximum of 10% of the excess, as per Revelle factor.
At last, I have read the works of Segalstad and Jaworoski. And I had a debate with Segalstad at a skeptics meeting in Brussels. Sorry to say it, but I have an uneasy feeling that he omits relevant information, which may give some of his viewpoints a complete different meaning… Where he is completely mistaken e.g. is the mixup of the residence time of CO2 in the atmosphere and the “adjustment” time, the time needed to remove an excess of CO2 above equilibrium, as the above example shows…
“Henry’s Law says that for a change in pCO2 in the atmosphere, the same change in pCO2 in water must follow (and reverse). But that is not a fixed ratio between pCO2(atm) and DIC, as you think, it is about a fixed ratio between CO2(atm) and free, gaseous, CO2 in water, whatever the concentrations of HCO3- and CO3–.”.
But it is a fixed ratio between CO2 and DIC. You’re assuming that CO2(aq) and DIC and independent and that’s not the case. CO32, HCO3 and CO2(aq) all exist in chemical equilibrium with each other. If you increase CO2(aq) you automatically increase CO32 and HCO3 by a corresponding amount. You cannot change CO2(aq) without changing HCO3 and CO32. They all exist in equilibrium.
“Thus to remove the extra 100% from the atmosphere, that takes many times longer than 10 years”.
Thanks for taking the time to explain Ferdinand, but unfortunately, I couldn’t follow any of that explanation and it doesn’t makse sense to me. I guess we’ll just have to agree to disagree.
Bart says:
July 20, 2012 at 7:07 pm
Considering this further, the estimates are based on measurements of carbon ratios between the ocean and the atmosphere above it. An implicit assumption has been made that the situation is static, and the only exchanges are in line with static laws. But, in fact, what we have here is a transport phenomenon of dynamic flows, in which upper waters of the ocean are flowing to the poles and sinking to the depths, then upwelling again in the tropics.
The measurements were done over several decades, over many area’s, thus showing the dynamic for all regions. The flux graphs are only for one year, 1995, which nowadays is used as reference year. Some of the regions changed over time from net sources to net sinks and in general the oceans increased in sink rate. But let’s have a look at what may happen of you change the temperature and/or concentrations of the deep ocean circulation:
The current exchange rate between the oceans and the atmosphere is ~90 GtC/yr out of the oceans and ~92 GtC/yr into the oceans. A large part is seasonal, especially in the mid-latitudes and another part is via the deep oceans: into the deep via the THC, mainly in the NE Atlantic and out of the deep in the tropical Pacific. My own estimate (based on the dilution of the “human” d13C fingerprint) is that about 40 GtC/year is exchanged between the atmosphere and the deep oceans. The exact height in exchange flux is not that important, but the change in flux is.
Now have a look at what happens if you have an increase of 1°C over all oceans, including the source and sink places (assuming constant deep ocean upwelling and concentration):
The current maximum difference in pCO2 between the warm pool and the atmosphere is ~350 microatm. That causes a source flux (into the atmosphere) of 40 GtC/year. With 1°C increase in surface temperature, the difference increases with 16 microatm. Thus the source flux increases to 41.8 GtC/year (CO2 fluxes are directly proportional to the pressure difference).
At the other side of the earth, the pCO2 difference is 250 microatm, giving 40 GtC/year of sink flux (assuming equilibrium at the start of the process). An increase of 1°C there also gives a change in 16 microatm, but that is at the cost of the sink rate, which decreases from 40 GtC/yr to 37.4 GtC/yr. In sum, there is an extra flux into the atmosphere of 4.4 GtC/yr. The first-year increase in the atmosphere thus is ~2.2 ppmv.
The following years, the incoming flux decreases somewhat and the sink flux increases somewhat, because of the increase of 2.2 ppmv in the atmosphere. The second-year increase in the atmosphere gets 1.9 ppmv. Ultimately after a few years, the increase in the atmosphere reaches ~16 ppmv, where the new ocean releases and ocean sinks are back into equilibrium, at an equal source/sink flux again of 40 GtC/year. That is without taking into account that the biosphere gives more sink with increased CO2 (which gives an overall average of 8 ppmv/°C)…
Thus an increase in sea surface temperature of 1°C only gives a maximum increase of 16 ppmv in the atmosphere within a few years.
Compare that to the continuous one-way release of 8 GtC (4 ppmv) per year from human emissions, surpassing the effect of a change of 1°C of the ocean’s surface within 4 years…
One can think of an increased circulation of the THC, or an increase of the deep ocean carbon content, but these are largely temperature independent on short term…
chipstero7 says:
July 21, 2012 at 5:36 am
But it is a fixed ratio between CO2 and DIC. You’re assuming that CO2(aq) and DIC and independent and that’s not the case. CO32, HCO3 and CO2(aq) all exist in chemical equilibrium with each other. If you increase CO2(aq) you automatically increase CO32 and HCO3 by a corresponding amount.
No, you are mistaken in the first sentence. Henry’s Law is only for the ratio of pCO2(atm) vs. pCO2(aq). Nothing else. Of course, there is a further dissociation into HCO3- and CO3–, but this dissociation is NOT constant, compared to pCO2(aq) or indirectly to pCO2(atm), because the chemical equilibrium changes, depending of the shift in pH with increasing or decreasing pCO2(aq) and the initial conditions of pH. That is where the Revelle factor comes in.
I couldn’t follow any of that explanation and it doesn’t makse sense to me
I know, it seems one of the most difficult points to explain. But think of a factory where you have invested some capital: The residence time is how fast the goods (and thus your capital) is going through the factory, the turnover time of capital and goods in the factory, while the adjustment time is the gain (or loss or break-even) of your money. While the turnover can be 1000% per year, the gain in general is much smaller…