While this article makes a strong case, looking at SST and CO2 can also be revealing:
A review of this WUWT post might also be instructive: A look at human CO2 emissions -vs- ocean absorption
From Columbia University: Oceans’ Uptake of Manmade Carbon May be Slowing
First Year-by-Year Study, 1765-2008, Shows Proportion Declining
(Click on image to view larger version)
Carbon released by fossil fuel burning (black) continues to accumulate in the air (red), oceans (blue), and land (green). The oceans take up roughly a quarter of manmade CO2, but evidence suggests they are now taking up a smaller proportion.
Credit: Samar Khatiwala, Lamont-Doherty Earth Observatory.
The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism during the industrial era suggests the oceans are struggling to keep up with rising emissions—a finding with potentially wide implications for future climate. The study appears in this week’s issue of the journal Nature, and is expanded upon in a separate website.
The researchers estimate that the oceans last year took up a record 2.3 billion tons of CO₂ produced from burning of fossil fuels. But with overall emissions growing rapidly, the proportion of fossil-fuel emissions absorbed by the oceans since 2000 may have declined by as much as 10%.
Some climate models have already predicted such a slowdown in the oceans’ ability to soak up excess carbon from the atmosphere, but this is the first time scientists have actually measured it. Models attribute the change to depletion of ozone in the stratosphere and global warming-induced shifts in winds and ocean circulation. But the new study suggests the slowdown is due to natural chemical and physical limits on the oceans’ ability to absorb carbon—an idea that is now the subject of widespread research by other scientists.
“The more carbon dioxide you put in, the more acidic the ocean becomes, reducing its ability to hold CO₂” said the study’s lead author, Samar Khatiwala, an oceanographer at Columbia University’s Lamont-Doherty Earth Observatory. “Because of this chemical effect, over time, the ocean is expected to become a less efficient sink of manmade carbon. The surprise is that we may already be seeing evidence for this, perhaps compounded by the ocean’s slow circulation in the face of accelerating emissions.”
The study reconstructs the accumulation of industrial carbon in the oceans year by year, from 1765 to 2008. Khatiwala and his colleagues found that uptake rose sharply in the 1950s, as the oceans tried to keep pace with the growth of carbon dioxide emissions worldwide. Emissions continued to grow, and by 2000, reached such a pitch that the oceans have since absorbed a declining overall percentage, even though they absorb more each year in absolute tonnage. Today, the oceans hold about 150 billion tons of industrial carbon, the researchers estimate–a third more than in the mid-1990s.
For decades, scientists have tried to estimate the amount of manmade carbon absorbed by the ocean by teasing out the small amount of industrial carbon—less than 1 percent—from the enormous background levels of natural carbon. Because of the difficulties of this approach, only one attempt has been made to come up with a global estimate of how much industrial carbon the oceans held—for a single year, 1994.
Khatiwala and his colleagues came up with another method. Using some of the same data as their predecessors— seawater temperatures, salinity, manmade chlorofluorocarbons and other measures—they developed a mathematical technique to work backward from the measurements to infer the concentration of industrial carbon in surface waters, and its transport to deep water through ocean circulation. This allowed them to reconstruct the uptake and distribution of industrial carbon in the oceans over time.
Their estimate of industrial carbon in the oceans in 1994—114 billion tons—nearly matched the earlier 118 billion-ton estimate, made by Chris Sabine, a marine chemist at the National Oceanic and Atmospheric Organization in a 2004 paper in the journal Science.
Sabine, who was not involved in the new study, said he saw some limitations. For one, he said, the study assumes circulation has remained steady, along with the amount of organic matter in the oceans. “That being said, I still think this is the best estimate of the time variance of anthropogenic CO₂ in the ocean available,” said Sabine. “Our previous attempts to quantify anthropogenic CO₂ using ocean data have only been able to provide single snapshots in time.”
About 40 percent of the carbon entered the oceans through the frigid waters of the Southern Ocean, around Antarctica, because carbon dioxide dissolves more readily in cold, dense seawater than in warmer waters. From there, currents transport the carbon north. “We’ve suspected for some time that the Southern Ocean plays a critical role in soaking up fossil fuel CO₂,” said Khatiwala. “But our study is the first to quantify the importance of this region with actual data.
The researchers also estimated carbon uptake on land, by taking the known amount of fossil-fuel emissions and subtracting the oceans’ uptake and the carbon left in the air. They were surprised to learn that the land may now be absorbing more than it is giving off.
They say that until the 1940s, the landscape produced excess carbon dioxide, possibly due to logging and the clearing and burning of forests for farming. Deforestation and other land-use changes continue at a rapid pace today—but now, each year the land appears to be absorbing 1.1 billion tons more carbon than it is giving off.
One possible reason for the reversal, say the researchers, is that now, some of the extra atmospheric carbon—raw material for photosynthesis–may be feeding back into living plants and making them grow faster. “The extra carbon dioxide in the atmosphere may be providing a fertilizing effect,” said study coauthor Timothy Hall, a senior scientist at NASA’s Goddard Institute for Space Studies. Many other scientists are now working to determine the possible effects of increased carbon dioxide on plant growth, and incorporate these into models of past and future climates.
Khatiwala says there are still large uncertainties, but in any case, natural mechanisms cannot be depended upon to mitigate increasing human-produced emissions. “What our ocean study and other recent land studies suggest is that we cannot count on these sinks operating in the future as they have in the past, and keep on subsidizing our ever-growing appetite for fossil fuels,” he said.
In a related paper in Nature, Khatiwala describes how the research was done.
“That leaves no option; the only net source is human activity.”
This is argumentum ad ignorantiam. You do not know of any other option, therefore the premise must be true. This is a commonly employed logical fallacy. Process of elimination only works if you have a fully known, compact set of alternatives. The recent unanticipated global cooling cycle should give any reasonable person grounds to suspect that the AGW establishment is not so thoroughly omniscient.
“Increasing sensitivity of what to what”
Increasing sensitivity of the level of atmospheric CO2 to the input forcing. Natural release of CO2 far outweighs that of anthropogenic sources on a yearly basis; I have been citing 3% as a widely accepted upper bound. See the post Bart (11:36:11) : here for some background. Don’t let the fact that I was assuming Philip_B’s value of 4% instead of my usual 3% confuse you.
The CO2/H2O equilibrium is complicated:
http://www.chem.usu.edu/~sbialkow/Classes/3600/Overheads/Carbonate/CO2.html
The simplest explanation is the information in the above link is that, for a given pH, the warmer the temperature of the water – the higher the pressure of CO2 in the air that will be in equilibrium with it. The alkali content of the water (“hardness” if you prefer) will ‘pull’ the carbonic acid / bicarbonate / carbonate distribution towards the carbonate, making room for more CO2 to dissolve in the water while lowering the pH *very* slightly.
The heat capacity of the ocean overwhelms the trace concentration of CO2 in the air and makes the temperature the driver of this system.
Bottom line, the ocean becomes a HUGE sink for CO2, and the correlation between CO2 levels and temperature shown in the “experience curve” demonstrates that this system is in equilibrium, so minor fluctuations in the CO2 levels from other sources will be dealt with quantitatively.
The real source of CO2 in the atmosphere (and the driver for ‘global warming’ models) is therefore whatever is supplying heat to the oceans: solar energy or geothermal energy (recall the Mid-Atlantic ridge, ‘black smokers,’ and the multi-year Gakkel Ridge eruption, to name just a few).
Bart (11:24:20) :
“This is argumentum ad ignorantiam.”
Oh, please. It is no such thing. Just imagine what you need to happen, for your idea to work. You would need either the oceans or land/biosphere to be a net source of carbon. If you try to put forward any other hypothesis (a CO2 pipeline from Venus, or volcanoes, or..), that hypothesis can be immediately shown to be untenable. So we’re back to air, ocean and biosphere/land. Pick a source, and then try to figure out how it can possibly be consistent with the observed fluxes and isotope data.
“Increasing sensitivity of the level of atmospheric CO2 to the input forcing.”
I still don’t follow what you mean. You add carbon to the system; it builds up in different places. What’s the big mystery?
“Natural release of CO2 far outweighs that of anthropogenic sources on a yearly basis; I have been citing 3% as a widely accepted upper bound.”
And what is the natural flow back out of the atmosphere, Bart? Why is it that you fixate on the arrows going up in this diagram, but not the arrows going down?
http://en.wikipedia.org/wiki/File:Carbon_cycle-cute_diagram.svg
Supercrit,
I don’t know how you figured out how fast the gas would dissolve in solution, but here is the equation I came up with to figure out the pressure.
P= (Henry’s K)(moles of CO2 gas)(Volume of CO2 gas)(R)(T)
——————————————-
((Volume Tank)(R)(T)+(Henry’s K)(Volume of CO2 gas))(Volume CO2 gas)
where Henry’s K is the Henry’s law constant (variable)
R is the Ideal gas law constant
T is temperature
So, I’m wondering where you got the 50 to 1 ratio.
I think it comes from the natural sources (and sinks) of CO2 being 50 times what man produces.
We don’t need to look for a source we already know that.
The reason CO2 doesn’t go up as fast as 4ppm per year is that about half is absorbed by the sinks one of which is the oceans.
And then there really is no simple rule of thumb for Henry’s law with temperature but there is an equation.
Henry’s Constant for temp T = H time e to the exponent -2400(1/T-1/298)
and I apologize for being in a hurry and not doing sub and superscripts for the above equation.
thanks
bob,
I got 1:50 ratio at 25 deg C from slide 23 of Tom Segalstad’s presentation:
http://www.slideshare.net/stevenfoley/gw-tom-segalstad
And Wiki gives “Partial pressure of CO2 in seawater doubles with every 16 K increase in temperature”
So, if this is right it looks like a sea temperature change of only 0.00032 deg C is required to see an outgassing of 2ppm of CO2!
Wow!
Sorry, correction:
Sea temperature increase of ~ 0.08 degrees needed to increase atmospheric CO2 by 2ppm.
Stil a ‘Wow!’ result?
There is an annual dip in CO2 caused by something water temp/flora/algae/etc.
http://img175.imageshack.us/img175/9698/manyco219992001.jpg
If absorbed by flora/algae (living stuff) then presumably the rise from the dip would be less than the fall into the dip – some CO2 would be retained by the growth. This is not apparent.
If it is sea water then its the wrong way up – summer would be higher CO2 (warm water). Also sea water is not saturated by CO2 so would it breathe with temperature?
Since 1974 the depth of the annual dip in CO2 (Start april end August) has increase from 14.5 to 20ppm approx:
http://img183.imageshack.us/img183/1212/depthofptbarrowdip.jpg
If warming is happening then sea water and air temp will be warmed to the same value where absoption occurs earlier each year:
days from jan 1st = -1.945E-04x + 2.377E+02
plot here:
http://img89.imageshack.us/img89/1610/barrowdateofminiman.jpg
Note that in Barrow there is little/no change in the date of minimum (.0002 days/year) but temperature has significantly increased.
There is an annual dip in CO2 caused by something water temp/flora/algae/etc.
http://img175.imageshack.us/img175/9698/manyco219992001.jpg
If absorbed by flora/algae (living stuff) then presumably the rise from the dip would be less than the fall into the dip – some CO2 would be retained by the growth. This is not apparent.
If it is sea water then its the wrong way up – summer would be higher CO2 (warm water). Also sea water is not saturated by CO2 so would it breathe with temperature?
Since 1974 the depth of the annual dip in CO2 (Start April end August) has increase from 14.5 to 20ppm approx:
http://img183.imageshack.us/img183/1212/depthofptbarrowdip.jpg
If warming is happening then sea water and air temp will be warmed to the same value where absorption occurs earlier each year:
days from Jan 1st = -1.945E-04x + 2.377E+02
plot here:
http://img89.imageshack.us/img89/1610/barrowdateofminiman.jpg
Note that in Barrow there is little/no change in the date of minimum (.0002 days/year) but temperature has significantly increased.
This will probably kill the thread but what the hell – sometimes you just gotta…
The Ordovician era. I came across an article on it from the palaeos web site (see link below). This era just after the Cambrian and its explosion of life has something interesting to say on the current climate debate.
http://www.palaeos.com/Paleozoic/Ordovician/Ordovician.htm
In AGW narrative a “plan B” exists in the shape of ocean acidification. We all know CO2 is increasing (leave aside for now whether its anthropogenic or not). Basically, if CO2 cant be relied on to warm the atmosphere, then at least it will “acidify” the oceans and dissolve all the beautiful coral. A kind of reserve catastrophe on the subs bench.
So what does the Ordovician era have to say on this subject?
(1) During the ordovician, atmospheric concentration of CO2 was 8-20 times higher than now.
(2) The Ordovician was a good era for marine lifeforms, including those with calcified parts (which contribute most fossils). “It was also one of the largest adaptive radiations in the Earth’s history.” In particular, it was the era in which corals first evolved.
(3) Did the oceans acidify due to the high atmospheric CO2 and kill of the coral? Evidently not.
(4) What kind of catastrophic warming was caused by the high atmospheric CO2? This kind: the era ended with one of the severest ice ages in earth’s history, of the “snowball earth” variety, with glaciers covering what is now the Sahara.
Christian creationists (who of course dont represent all christians) recognise history only 6000 years back. For AGW proponents, the earth began in 1850. However for the CO2 linked AGW hypothesis to hold water, it needs to be credible in the context of well established palaeohistory of climate. In the Ordovician, the hypothesis fails absolutely.
carrot eater (12:07:39) :
“Oh, please. It is no such thing.”
This shows you do not understand the tenets of formal logic or the minimum requirements for proof. This is the kind of thinking which led humankind for centuries to believe that bleeding patients with leeches would cure illness, or that “night gases” were responsible for sickness, or that regular bathing was bad for your health. Not knowing of microbial life, they had exhausted all other possibilities, therefore, the logic of their conclusions appeared inescapable.
We like to imagine that we are intellectually superior to our forebears, merely because we know more. But, the processes of logic never change, and though the fallacies to which we cling may become more sophisticated, to them we remain magnificently vulnerable via our innate hubris.
“I still don’t follow what you mean. You add carbon to the system; it builds up in different places. What’s the big mystery?”
It doesn’t just build up, it also dissipates. The rate at which it builds up and dissipates is key to the entire puzzle. By placing a limit on the rate at which we are forcing the buildup (my 3%), we gain insight into the possible trajectories of its concentration as a result of our actions, and can falsify various hypotheses as to how it will all unfold.
“And what is the natural flow back out of the atmosphere, Bart?”
That is my whole point. And, that outward flow rate is lower bounded by the rate at which we are putting emissions into the air, the rate at which we have observed concentrations rise, and the plausibility of the given flow rate models.
carrot eater (10:45:25)
“The paper I had in mind was “Fate of fossil fuel CO2 in geologic time”, Journal of Geophysical Research, vol 110 (2005).”
I found the paper here. Color me unimpressed. A paper this sketchy would never have passed the peer review of the journals in my field in which I have been published. It is difficult to grasp his entire methodology given the level of detail. But, at the very least, I notice two things:
1) He states that “the maximum amount that could ultimately be released would seem to be about 5000 Gton C, on a timescale of several centuries.” He then projects his two significantly alarming accumulation projections based on “…2000, and 5000 Gton C are released following a Gaussian trajectory of 150 years half-width centered on the year 2100.” That is, he releases 40% and 100% of the entire reservoir in a mere 150 years.
2) The responses have a large transient, which indicates only the degree to which his forcing exceeds the bandwidth of his assumed system response, and when you are pumping out so much in such a short time, and assuming a 1000 year fundamental time constant, it is hardly surprising that you get a huge blip before the system eventually settles out in the very long term steady state to just barely above the level he started with.
In short, the worst case results in this analysis are almost completely conjectural, and depend critically on assumptions which are not based on real world behavior.
“The Global Carbon Project or somebody else must have stuff available to look at.”
Meaning, you have taken it on faith that “somebody else” has looked at this, and that is good enough for you. It is not good enough for me.
Bart (12:28:39) :
Spare me the lecture on unrelated matters. You are asserting that somehow, the accumulation of CO2 in the atmosphere could somehow unrelated to the carbon being added to the carbon cycle by use of fossil fuels (along with deforestation). Instead of speaking of leeches, you might put forth some hypothesis as to how this might be, and how such a hypothesis would be consistent with observations.
“It doesn’t just build up, it also dissipates.”
By dissipate, I assume you mean the accumulation in the oceans. If that’s what you’re interested in, just study what we know about ocean-atmosphere exchange.
“I found the paper here. Color me unimpressed. A paper this sketchy would never have passed the peer review of the journals in my field in which I have been published.”
It is a short one, yes; don’t read it in isolation. I just gave you a starting point. You can follow up on the rest of the literature from there. Archer has also a book on the topic.
“He then projects his two significantly alarming accumulation projections based on “…2000, and 5000 Gton C ”
He did it for 300, 1000, 2000 and 5000. The amount we’ve already emitted is in the 300 range, isn’t it? Why did you neglect to point that out? The rest of your points fall out from there, I’d say. What I’m meaning for you to look at is the actual physics. These aren’t mathematical abstractions; there are actual physical processes at hand.
“Meaning, you have taken it on faith that “somebody else” has looked at this, and that is good enough for you. It is not good enough for me.”
I’ll speak for myself, thanks. I had the impression you couldn’t get behind paywalls, so I was offering a place where you might find information, outside the literature. Chapter 7 of IPCC WG1 probably also has a review of the area.
carrot eater (16:23:34) :
“Spare me the lecture on unrelated matters. “
Spare me the pose. If you are uninterested in formal logic, there is no point in further discussion. You can go back to reading chicken entrails or beseeching burning bushes for enlightenment if that is what you choose, it does not really matter to me.
“He did it for 300, 1000, 2000 and 5000. The amount we’ve already emitted is in the 300 range, isn’t it? Why did you neglect to point that out?”
The increases for the first two cases do not appear to be particularly worrisome, so I focused on the latter two. That is why I stated “…his two significantly alarming accumulation projections…”.
For the rest, I have to admit, I was not familiar with the currently claimed levels of output. I jumped to the conclusion that, after he had stated that “the maximum amount that could ultimately be released would seem to be about 5000 Gton C, on a timescale of several centuries,” and he then appeared to proceed to release it all over a 1.5 century interval, then by his own description, he appeared to have speeded up the process considerably. That, however, may not be the case, depending on what he meant by “Gaussian trajectory”, which suggests different types of functions in different disciplines. It could mean that his effective forcing interval is at least 300 years, which can fit the definition of “several”. The details of how that trajectory is formed are, lamentably, missing.
Regardless, it still falls flat, because in the time that anthropogenic emissions would be 2000 to 5000 Gtons, natural processes would add over 100 Tera-tons. So, we have a net 5% or so additional input at most. To get the type of amplification he is projecting, his model has to be extraordinarily sensitive to high frequency behavior (the model has to be dependent on derivatives of the forcing rate) or his marginal sensitivity has to be extraordinarily high (the system is very nonlinear), and his dominant time constants have to be extraordinarily and unrealistically long (the very fact that the rise in CO2 concentrations of the last 50 years is only half of the recognized anthropogenic forcing is not compatible with the asserted 1000 year dominant time constant).
I have argued each and every one of these points over this series of exchanges with you. If you can point me to sources which have detailed mathematical descriptions of the model or models, then I can deconstruct them for you and tell you precisely what is going on, and which parts of the models are, by my lights, reasonable and which are not. Otherwise, I believe we are at an impasse, and we no doubt both have more productive uses for our time than to continue reiterating points we have already made to one another.
Supercritical —
See the pink graph at the top of this thread. Increase of 0.265C corresponds to a rise of 40 ppmv CO2.
Correlation of SST with atmospheric CO2 is 0.996.
Sabine, who was not involved in the new study, said he saw some limitations. For one, he said, the study assumes circulation has remained steady, along with the amount of organic matter in the oceans.
The old Economics joke about this “technique” is “Given these conclusions, what assumptions can we draw?”..
The organic stuff in the ocean is not constant. The circulation has not remained steady. (PDO, AMO, … these things show change.)
They say that until the 1940s, the landscape produced excess carbon dioxide, possibly due to logging and the clearing and burning of forests for farming. Deforestation and other land-use changes continue at a rapid pace today—but now, each year the land appears to be absorbing 1.1 billion tons more carbon than it is giving off.
In other words, they have no clue and are ASSUMING it must be land use doing it… How can you on the one hand say continued and accelerating clearing of the Amazon now is raising CO2 but CO2 is being absorbed more on land, yet say that in the past when we had much more of the Amazon, it was absorbing less?
These folks are just making stuff up.
http://chiefio.wordpress.com/2009/06/02/of-trees-volcanos-and-pond-scum/
http://chiefio.wordpress.com/2009/02/25/the-trouble-with-c12-c13-ratios/
I also note in passing that this is Yet Another Article that purports to look at CO2 absorption into the ocean and completely ignores the issue of very cold rain acting as a “stripper column”. Anyone who does ChemE stuff knows that when you want to strip a gas of a contaminant one of the best ways to a counter current flow of solvent drops or mist. Far better than sitting over a puddle of solvent.
And we have a sky filled with cold falling water. Some is snow, some is sleet, some is just rain. ALL of it, even fog, an ideal CO2 absorber / stripper. Heck, wasn’t Acid Rain in part blamed on carbonic acid? Were not caverns in limestone reputed to be leached by carbonic acid in rain? How did we get so much carbonic acid without stripping CO2?
Yet they focus on a large flat body of water with minimal surface area and much slower flow rates as The Thing.
Just Silly.
If you would understand what happens in the air and to the gas mix, you must look at the CONSTANT global flow of thousands of tons of microscopic sized scrubber droplets of COLD water falling through that air and floating around as clouds. Not the warm interface of a quiet tropical sea…
I think they need to hire some ChemE guys in climate science departments …
contrarian,
thanks for mentioning the pink graph formula; I had not wanted to use it to broach the subject. But since you have, it seems that the Mauna Loa measurements of 2ppm/yr could be explained by a local sea-temperature increase of 0.0128 deg C/yr
Now apart from the physical near-impossibility of measuring such a temperature difference directly, there would be the question of where and how this heat could be coming from.
As I understand it, Mauna Loa is a shield volcano, and apart from the ‘runny’ lave-flows running into the local sea to heat it up, there is the possiblity of a local network of undersea hydrothermal vents also adding to local warming. We are looking at a temperature rise of around 13 thousanths of a degree!
[PS as an aside, might Mauna Loa’s NDIR measurement of airborne C02 in ppm, be more an actual example of an exquisitely sensitive thermometer rather than evidence of AGW?]
And E.M.Smith,
The idea of raindrops acting as powerful scrubbers leads to the question of crystallisation.
What is the difference in CO2 absorbitivity between the various phases of water?
And when there is a rapid phase-change, say when ice-crystals form, is there a consequent rapid release of C02?
supercritical —
The Mauna Loa figures are quite consistent with trends from other monitoring stations. There is also now a satellite which makes global measurements. The Mauna Loa readings do not seem to be a local effect.
http://cdiac.ornl.gov/trends/co2/sio-keel.html
Contrarian,
Even if the Mauna Loa figure of 2ppm/yr increase in atmospheric CO2 was not local, you would agree that a sea-surface temperature rise of 13 thousandths of one degree per year would be sufficient to cause such an increase?
supercritical (01:55:09) :
“Sea temperature increase of ~ 0.08 degrees needed to increase atmospheric CO2 by 2ppm.”
Well, plotting the Mauna Loa year-on-year increase against the year-on-year change in SST indicates the short term (~1 year) response of atmospheric CO2 to change in average sea surface temperature is about 5 PPM/C. This SST driven variation is superimposed on a gradual emissions driven increase in atmospheric CO2, partially off-set by ocean absorption and increased uptake by plants. (see “A look at human CO2 emissions -vs- ocean absorption” and the comments that follow, that Anthony referenced above, if you have not already done so).
The pink graph above hides the short-term temperature response because of the 21-year moving average of temperature increase. Only the top (100 – 200 meters or so) of ocean has changed much (~0.4C) in temperature past 50 years; the deep ocean (which has ~95% of the ocean’s volume and CO2 absorbing capacity) has hardly changed at all in temperature over that 50 year period. So the volume weighted average increase in ocean temperature over the past 50 years is tiny (probably in the range of 0.02C).
The 21-year lagged increase in sea surface probably correlates well with the increase in atmospheric CO2 because the slow, long-term SST rise is being driven by radiative warming from increased atmospheric CO2 (and other infrared absorbing gases), not because the CO2 level is being driven by sea surface temperature changes. Increases in SST (from about 1900 on) are consistent with a relatively low climate sensitivity to radiative forcing: a little under 1 degree C for the radiative forcing that comes from doubling CO2 in the atmosphere, as lots of people have observed. (Which is in contrast with the IPCC, which suggests ~3C warming for a doubling of CO2.)
E.M.Smith (00:32:05) :
I am not qualified to comment on the “stripping” action, but there is a hell of a lot of surface area there. Do you have any reliable references in which this is studied?
As another mathematically challenged lurker, following is a simple minded analysis I did back in mid 2004.
3) http://cdiac.esd.ornl.gov/ftp/ndp030/global.1751_2004.ems
From tables accessible at 2) and 3) we can do some decadal average annual analysis as:
Decade 1 2 3 4 5
Years ’54-63 ’64-’73 ’74-’83 ’84-’93 ’94-`03
Ave. annual fuel emissions (Gt/yr) 2.4 3.4 5.0 6.0 6.7
Percent change decade to decade 42 47 20 12
Ave. annual atmos. conc’n delta (ppm/yr) 0.8 1.1 1.4 1.5 1.8
Atmos. conc’n delta per Gt emission (ppB) 333 324 280 250 270
Implied atmospheric retention (Gt) 1.7 2.3 2.9 3.1 3.7
Airborne fraction (%) 71 68 58 52 55
Ocean uptake from fuel (Gt) 0.7 1.1 2.1 2.9 3.0
Deforestation factor (%) guesstimate* 1.03 1.06 1.09 1.12 1.15
Total emissions (Gt) 2.5 3.6 5.5 6.7 7.7
Airborne fraction of total (%) 68 64 53 46 48
Ocean uptake total (Gt) 0.8 1.3 2.6 3.6 4.0
*The above fuel emissions from 3) do not include any factor for deforestation/land use. Recent total emissions have been estimated by AGW advocates as slightly less than 8 Gt/yr total, giving about an additional 15% for deforestation/land use. As deforestation is to a degree linked to third world population, we can assume that factor was sequentially lower going back to prior decades. Using a higher factor for prior decades won’t change anything much. Column 3 fuel emissions data corresponds almost exactly with IPCC SAR figures.
While total average annual emissions have gone up by a factor of 3, ocean uptake has gone up by a factor of 5. That is hardly consistent with slow mixing or near saturation of surface waters. What seems to be happening is that increasing atmospheric partial pressure is increasing the rate of ocean uptake with the rate of increase slowed by surface
Steve Fitzpatrick,
I am not convinced that consideration of deep ocean water has any relevance, unless the surface water becomes somehow saturated with CO2 to the point where Henry’s law stops working.
As I understand it, Henry’s law is saying that the big factors driving the amount of CO2 to be found in the atmosphere, and in seawater, are a) the gas partial pressure and b) the temperature of the sea surface water.
If the atmospheric pressure of CO2 is to rise, then Henry’s law predicts that we would have to add ~50 times this amount to begin with, as ~ 49/50 of the extra amount will dissolve in the seawater, leaving only 1/50th in the air. So, for an observed increase of 2ppm in the atmosphere , where is that 100 ppm coming from?
But, we would not have to add any extra CO2 if we warmed the water by 0.08 degrees, because Henry’s law predicts that CO2 would then out-gas from the seawater until the atmospheric CO2 increased by 2ppm.
I conclude from these rough first-order considerations, that;
– The CO2 increase is more likely to come from a tiny amount of sea-surface ocean warming, than say from Anthropic or other sources.
– If Anthropic CO2 is estimated at say 4 ppm/yr, then Henry’s law predicts that 98% of this added amount will be absorbed by the seas, leaving the Anthropic increase as only 0.08ppm/year
(in other words, Man’s responsibility is for around 4% of the annual increase in atmospheric CO2. And, given a climate sensitivity of 1 degree for a doubling of CO2, then man’s activity speaks for one ten-thousanths of a degree per year, or so)
And unless someone can show that these considerations are way way wrong, I for one do not think that AGW is a starter.
Supercritical,
It is plausible (based mainly on Henry’s Law) but there are complicating factors, e.g., buffering. Seems the sort of question that could be answered experimentally, i.e., de-gassing a volume of seawater, introducing an atmosphere above it with a known concentration of CO2, and measuring the equilibrium points at different temps. Don’t know if anyone has done this.
Of course, if atmospheric CO2 is the effect, not the cause, of rising SSTs, then you need another energy source for the temp increase.
Steve F —
” Increases in SST (from about 1900 on) are consistent with a relatively low climate sensitivity to radiative forcing: a little under 1 degree C for the radiative forcing that comes from doubling CO2 in the atmosphere, as lots of people have observed.”
Yes. But if there is another driver of SST temps, then the sensitivity to CO2 is even lower.
The 50-year long period of increased solar activity (about 1950-2000), and the possible effect on cloud formation (and thus reduced albedo) has not been ruled out, as far as I know. I believe Dr. Spencer is working on this.
Supercritical,
For sure, there is nothing wrong with Henry’s law!
The ocean uptake is actually a bit more complicated, because much of the absorption/desorption is related to chemical combination of CO2 with carbonate ions to form bicarbonate. The pH of ocean water (about 8.3, I think I remember) and the level of dissolved carbonate gives the ocean substantial additional capacity for absorption of CO2 compared to what the partial pressure of CO2 in the atmosphere would yield over pure water.
To simplify things, let’s consider how much the top 100 meters of ocean could adsorb/desorb from the atmosphere for a 1C change in temperature, without considering the buffering action of carbonate ions. I choose 100 meters because that is where most of the year-on-year change in ocean temperature takes place.
One atmospheric pressure of pure CO2 in equilibrium with pure water gives a weight fraction of CO2 of about 2 grams/liter at 15C (about the average surface temperature of the ocean). At 388 PPM partial pressure (the present atmospheric pressure of CO2), the solubility in pure water at 15C would be about 2 * 388/1000000 = 0.000776 gram per liter. Increase the temperature by 1C, and the solubility would fall by 3.4%, or a change of about 0.000026 g/liter.
How much weight of atmosphere is above the ocean? ~1 kg per sq. cm. The weight of CO2 in all the atmosphere directly above one square cm is about 1000 * 0.000388 *44/29 = 0.59 gram. The factor of 44/29 accounts for the higher molecular weight of CO2 compared to N2 and O2. So all the CO2 in the atmosphere above 1 one square cm is about 0.59 gram.
Now consider how many liter’s of water lie below that same square cm of water surface if you go down to 100 meters (the region that subject to relatively rapid temperature changes). The volume is 100 meters * 100 cm/meter * 1cm sq. = 10,000 cm cubed, or ~10 liters. We calculated above that the concentration of CO2 in 1 liter of water in equilibrium with the atmosphere is ~0.000776 g at 15C, so in that 10 liters, the total weight of CO2 dissolved (at equilibrium with 388 PPM in the air) would be about 0.00776 gram, while the weight in the air above is about 0.59 gram. In other words, the top 100 meters would contain only about 1.3% as much CO2 as is in the atmosphere above. For a change of 1C in temperature, the dissolved CO2 in the top 100 meters (under 1 sq cm) would drop by ~3.4%, or about 0.034*0.00776 = 0.00026 gram. So if we warmed the surface of the top 100 meters from 15C to 16C, at equilibrium the ocean would off-gas 0.00026 g/cm sq.
So how much of a change in the atmosphere doe this correspond to? It is, 0.00026g/1000g = 2.6 PPM by weight per degree change for the top 100 meters. Since atmospheric CO2 concentration is normally expressed as volume fraction (not weight fraction), the atmospheric change would be ~2.6 * 29/44 = 1.71 PPM by volume Now, since the ocean covers only ~70% of the Earth’s surface while the atmosphere coves 100%, the actual response would be higher by a factor of 1/0.7, or about 1.71 PPM/0.7 = 2.44 PPM per degree C. Note that this assumes equilibrium is established between the atmosphere and the top 100 meters of ocean (which may not be correct). Because of the buffering/chemical neutralization of carbonate ions, the actual rate of desorption/adsorption is higher than pure water. The year-on year change in atmospheric CO2 that can be attributed to changes in average ocean surface temperature is in the range of 5 PPM per degree C (as I noted in my earlier comment), due mostly to the much higher absorption capacity of buffered ocean water compared to pure water, partially off-set by less than perfect approach to equilibrium between the atmosphere and the ocean surface.
If you extend the above calculation for water to the bottom of the ocean (about 4000 meters deep on average, then the change in atmospheric CO2 per degree would be (for pure water) 40 times larger, or about 100 PPM per degree C change. For buffered sea water, the capacity of the whole ocean is substantially higher.
However, please keep in mind that the deep ocean (below a few hundred meters) has not changed by more than a couple of hundreths of a degree in the last 50+ years (if that!), so the CO2 in the deep ocean has not been released by surface warming.
In the real world, the deep ocean is always very cold (it is fed by sinking very cold water near the poles), and so it has an even high CO2 holding capacity. Upwelling water in the tropics actually out-gases CO2 as warms, while very cold water at high latitudes absorbs CO2. The ocean on average is a large sink for CO2 because the sinking very cold water absorbs more CO2 than the warming upwelling water out-gases. The cold water sinking now is not going to release that extra CO2 to the atmosphere until it return to the surface a long time from now (somewhere between 750 and 1500 years, depending on what circulation rate data is correct). So the ocean will continue to be a net absorber of CO2 for many centuries to come.
As the concentration of CO2 in the air rises, the weight of CO2 lost to the deep ocean will continue to rise.
Finally, the paper about loss of ocean uptake capacity (above) looks pretty shaky to me. I think the authors go about it ass-backwards. The simplest approach is to determine (chemically) how much absorption capacity there is for real ocean water samples by measuring at different CO2 concentrations in air. To try to estimate the ocean’s capacity based on uncertain historical records of land use and fossil fuel use is extremely uncertain.
E.M.Smith (00:32:05) :
I also note in passing that this is Yet Another Article that purports to look at CO2 absorption into the ocean and completely ignores the issue of very cold rain acting as a “stripper column”.
see (repeated below):
bill (09:15:54) :
There is an annual dip in CO2 caused by something water temp/flora/algae/etc.
http://img175.imageshack.us/img175/9698/manyco219992001.jpg
If absorbed by flora/algae (living stuff) then presumably the rise from the dip would be less than the fall into the dip – some CO2 would be retained by the growth. This is not apparent.
If it is sea water then its the wrong way up – summer would be higher CO2 (warm water). Also sea water is not saturated by CO2 so would it breathe with temperature?
Since 1974 the depth of the annual dip in CO2 (Start April end August) has increase from 14.5 to 20ppm approx:
http://img183.imageshack.us/img183/1212/depthofptbarrowdip.jpg
If warming is happening then sea water and air temp will be warmed to the same value where absorption occurs earlier each year:
days from Jan 1st = -1.945E-04x + 2.377E+02
plot here:
http://img89.imageshack.us/img89/1610/barrowdateofminiman.jpg
Note that in Barrow there is little/no change in the date of minimum (.0002 days/year) but temperature has significantly increased.
Surely in NH rain will be warm and less in summer = less CO2 uptake and Cool and more in winter = more CO2 uptake.
This does not agree with the 20ppm dip from spring to late summer seen at pt Barrow Alaska.
Also at the end of july / beginning of August the CO2 starts to be released back into the atmosphere from where ever it was stored. Woul slightly cooloing ocean give it up?
If plankton then warm water+sunlight= growth = uptake of CO2?
But does death of plankto release the CO2 back. If incorporated in shells would it not sink?
Land based growth would absorb for leaf growth but would decay release it back so quickly?
Thoughts?