Bishop Hill A new look at the carbon dioxide budget
Jul 30, 2013 Climate: carbon budget As readers are probably aware, I don't spend a lot of time on new hypotheses about global warming. Apart from intermittent looks at Svensmark's cosmoclimatology work, I've tended to concentrate on mainstream science and its relationship with policy, as well as a lot of "meta" stuff like peer review.
However, I was recently sent a paper by reader David Coe that piqued my interest. It seemed to me to be put together pretty well, and was about an area of the science that I knew nothing about. Being somewhat wary about this kind of thing though, I've sought expert opinion, and this suggests that at least some of what is said is good and new and interesting. So I am going to post the paper up, with the caveat that it is only a discussion paper and parts of it may be wrong. Readers are cordially invited to throw stones at it.
The paper is written in four parts, which I will post at a rate of one every 3-4 days.
Here is the first part, which sets out the problem.
Reader Comments (122)
doughie
The coal seams are on the continental plates. They are unlikely to subduct directly, which mostly happens to sea floor material beyond continental shelves.
However, material eroded from coal seams and deposited as deep sea sediments would subduct.
If there are meaningful transmission bands the type of person to elucidate might be a Spectroscopist rather than an Oceanographer
There is, indeed, a fundamental conflict between the two claims that A) CO2 has been remarkably stable over hundreds of years and B) anthropogenic inputs, which are tiny relative to the natural flows, can significantly upset this balance.
A CO2 regulatory system which can be so easily influenced under the second assumption cannot remain stable as per the first in the face of random natural fluctuations. It would necessarily exhibit an effective random walk over lengthy time periods, with the divergence from an initial point growing as the square root of time.
Atmospheric CO2, as Murry Salby has explained, and as this graph almost trivially shows, is overwhelmingly a result of integrated variation in average global temperature.
@Clive Best,
"The peak for atmospheric OLR occurs for ~ 300ppm which just happens to be that found on Earth naturally. Can this really be just a coincidence ? It is almost as if convection and evaporation act to generate a lapse rate which maximizes radiation cooling by CO2 to space."
OLR = Outgoing longwave radiation, from
http://climateaudit101.wikispot.org/Glossary_of_Acronyms
Interesting observation. And thank you, Dr. Best, for lots of other cool, interesting stuff at
http://clivebest.com/blog/
Cheers -- Pete Tillman
Professional geologist, amateur climatologist
Why the title "budget" and not presenting a first balance of carbon emitted vs carbon retained in the
atmosphere?.
Boden at al. at CDIAC publish the total tons carbon emitted since 1750.
Thus following approximation:
Total emitted carbon up to 2009: 350’000’000’000’000 kg or 2.91·10e13 kmole
Mass of air: 1013 mbar over 510'072'000 km2 corresponding to 5.268·10e18 kg or 1.82·10e17 kmole
(this is simplistic bot not too wrong).
Expected concentration increase if no other carbon sink is available: ( 2.91·10e13/1.82·10e17) = 160 ppm
Observed concentration increase: 388 – 280 = 108 ppm
It can be interpreted that 108/160 = 68% of the total emitted carbon have remained in the atmosphere
and 32% were absorbed as additional biomass or as carbonates in sediments.
When looking at the yearly additions this ratio remains in the same order of magnitude.
Picking up on the following from the paper:
"Furthermore there appears to be no physical or chemical reason why two totally different
processes, photosynthesis, and organic respiration and decomposition should balance......not
a positive Net Biome Production?"
"Would we not expect these biological mechanisms contributing to Rh, to be temperature
dependent and thus also to be seasonally variable? If we wish to arrest vegetative decay, do
we not simply freeze it? In the case of Point Barrow and Alert, ....... flux source Rh that, according to TAR, would be expected to achieve that rebalance, has also shut down because of sub‐zero Temperatures."
The processes of photosynthesis and decomposition need not balance but are obviously linked through the carbon cycle and in the absence of a massive perturbation in the mechanisms of the processes e.g. plant or bacterial evolution or the modification of the environment e.g. reduction in light and temperature etc. are dependent on each other.
A large transient pulse in biological mechanisms or the environment could cause a gigantic imbalance between the rates of decomposition and photosynthesis that explains the production of fossil fuels. Significant environmental perturbations to these mechanisms occur in a gradual annual cycle that causes a phase displacement between the processes. In the Northern hemisphere with its greater mid and high latitude land mass the environmental perturbations are greater as surface temperature variations are far higher.
Carbon dioxide is well mixed in the atmosphere so the polar regions carbon cycle is not isolated. Winter temperatures in the temperate zones are not sufficiently low to halt bacterial metabolism they just slow it.
The rate of photosynthesis is dependent on light intensity, availability of water and temperature. The rate of decomposition is sensitive to temperature but also dependent on the presence of organic detritus and water. Surface temperature lags maximum light intensity by 1-2 months. Autumn releases high levels of organic detritus, and there is increased availability of water. The population of bacteria and fungi has to be given time to grow and colonise the autumnal detritus pulse. In lower temperatures this population growth is slower so the relaxation time would be longer. The carbon dioxide produced is circulating within the Ferrell Cell and this will cause a further phase lag in the growth of surface carbon dioxide levels.
If conditions that exclusively favour decomposition in mid latitudes such as high winter temperatures and high rainfall and or exclusive photosynthetic conditions are unfavourable such as low summer light intensity due to high cloud cover etc. this analysis leads towards a trending increase in carbon dioxide concentrations that would be greater in the Northern Hemisphere. Although my gas fired central heating boiler is still doing its bit during the winter months.
"Arguably, 280 ppm was getting dangerously low, and we have saved the world from slow-moving disaster on a timescale of tens of millions of years. Maybe the next dominant species to come along will be grateful."
Thanks for that post NiV. A lot of the hysterics about CO2 seem to miss the point that it is not a pollutant but a vital part of the life cycle of almost every living organism on Earth.
Trago12
You may well be right. However, I repeat, what is the source of the arctic circle restorative CO2 flux which occurs during the winter months?
David, another couple of issues you might like to take on/in: O2 is not stable in a 'dead' atmosphere; its duration would be measured in fractions of geologic time. It was driven from 0% up to 20% by life, and is evidently maintained there.
Also, much (most?) of the sequestered CO2 is in the form of limestone. Orogenesis raises this old seabed to erodable heights, where it re-enters the biosphere. What happens to it? Does it drain into the seas and help maintain the CaCO2 buffer?
Finally, plants necessarily eat CO2 down to famine levels and then hover there. Our Gaia-given role seems to be to lift them back up to more (temporarily) healthy levels. Our CO2-release tech will have to become much more efficient to maintain a higher level, though. ;)
Brian H
It is my belief that photosynthetic activity is the primary driver for CO2 and O2 with the oceans providing the control element. In part 2 I try to explain and formulate mathematically the control equations which determine this activity. Human activities are simply a perturbation of this process. Hopefully Andrew will post this up in the next day or so.
David: The formation of sea ice could be the source of some of the CO2 that appears in the Arctic every winter. Freezing of surface water on land and moisture in the soil could also contribute. Lots of carbon dioxide can dissolve in water (and even more when it is colder), but individual carbon dioxide molecules probably don't fit into the crystal structure of ice. Dissolved salts are also released from water when it freezes for the same reason.
For obvious reasons, it would therefore be interesting to see how CO2 varies at high latitudes in the Southern Hemisphere. I believe there is a station at the South Pole, but it may be somewhat isolated from the coast where seasonal freezing occurs by the descending branch of the Ferrel cell. The local geography and winds certainly play a role in the amplitude of seasonal changes in CO2. The station on Moana Loa reported only measures CO2 at night when off-shore breezes bring fresh descending air from higher altitudes in the Central Pacific.
We now apparently have satellites monitoring near-surface CO2 concentration globally from space and hope to enforce any future emissions treaty by monitoring large emitters from space. http://www.cbsnews.com/2100-202_162-4748817.html
Sea ice contribution to the air–sea CO2 exchange in the Arctic and Southern Oceans
SØREN RYSGAARD et al
DOI: 10.1111/j.1600-0889.2011.00571.x
Tellus B
Volume 63, Issue 5, pages 823–830, November 2011
ABSTRACT
Although salt rejection from sea ice is a key process in deep-water formation in ice-covered seas, the concurrent rejection of CO2 and the subsequent effect on air–sea CO2 exchange have received little attention. We review the mechanisms by which sea ice directly and indirectly controls the air–sea CO2 exchange and use recent measurements of inorganic carbon compounds in bulk sea ice to estimate that oceanic CO2 uptake during the seasonal cycle of sea-ice growth and decay in ice-covered oceanic regions equals almost half of the net atmospheric CO2 uptake in ice-free polar seas. This sea-ice driven CO2 uptake has not been considered so far in estimates of global oceanic CO2 uptake. Net CO2 uptake in sea-ice–covered oceans can be driven by; (1) rejection during sea–ice formation and sinking of CO2-rich brine into intermediate and abyssal oceanic water masses, (2) blocking of air–sea CO2 exchange during winter, and (3) release of CO2-depleted melt water with excess total alkalinity during sea-ice decay and (4) biological CO2 drawdown during primary production in sea ice and surface oceanic waters.
Bishop.
to quote the author: why why why.
when you see someone proclaim violations of the second law, put the paper down.
when the number of exclamation marks is greater than zero, put the paper down.
David: Your "Unanswered Questions" in Section 1.2 appear to be somewhat naive to this chemist, who is familiar with rate equations and equilibria. Anytime the rate constants for transfer of CO2 between two reservoirs are fast enough, this part of the system will be near equilibrium (280 ppm pre-industrial for example).
It also sounds naive to ask what "controls" the partitioning of carbon dioxide between various reservoirs. The rate constants do. For a system at equilibrium between reservoirs 1 and 2, the amount of CO2 leaving reservoir 1 is k_12*[CO2_1], where k_12 is the rate constant for moving from reservoir 1 to reservoir 2 and [CO2_1] is the concentration of CO2 in reservoir 1. At equilibrium, the partitioning is determined by the ratio of the rate constants (which chemists call the equilibrium constant).
k_12*[CO2_1] = k_21*[CO2_2]
[CO2_1] / [CO2_2] = k_21 / k_12 = Keq
Rarely, the rate at which CO2 is transferred to a different reservoir won't depend on the amount of CO2 in the current reservoir. Plants growth can be limited by sunlight and nutrients as well as CO2. The rate at which CO2 enters and leaves the deep ocean depends on the rate at which water is convected to the mixed layer, not how much CO2 it might contain. (Also see Lake Nyos).
Why has half of anthropogenic CO2 emissions disappeared into various sinks? For me, why is the wrong question. IMO, the right question is: Is the IPCC's system of rate constants for CO2 transfer between various reservoirs consistent with the amounts and changes we measure? That includes CO2 with minor isotopes, which have different rate constants for some processes. How much can these rate constants be varied and still be consistent with observations?
Frank
Please take a look at Part 2 which, if all goes well, Andrew will be posting tomorrow. I think that you might find we are thinking along similar lines. Unfortunately for the past 30 years the IPCC contributors have been looking in other directions.
steven mosher
I understand that you may not like the style, born from frustration with reading inept science referenced by the IPCC. If you must take umbrage, however, please do it with the science and ideas. I believe that the explanation of CO2 partition between atmosphere, oceans and biosphere offered by the IPCC assessment reports does actually violate the second law, an act that any competent physicist would instinctively avoid. In an earlier comment I explained further why I believe that to be the case. If you disagree then please offer your counter argument. If you are correct I will be the first to acknowledge it.
Frank
With reference to your first post, when I first began researching these issues I considered that CO2 release by polar ice formation might provide the additional CO2 source required for the restoration of winter levels in the arctic. I concluded however that the effect was at least an order of magnitude smaller than was required.
As far as the reference to RYSGAARD et al is concerned, please read part 2 tomorrow to see why I am singularly unimpressed by such offerings. I will greatly appreciate your views, positive or otherwise. I am not expecting an easy ride.
Hi David,
I read through your post and thought that you hit some points well, such as the carbon balance but swung and missed when you got into the thermal aspects of the oceans.
Truthfully I hope to read far more on the carbon budget and some of the issues inherent to that analysis. It is an area of research which seems to be glossed over grossly in favor of modeling. The actual production and absorption of CO2 does not conform well with some satellite measurements showing more CO2 coming from warmer regions.
There are two aspects of your deep oceans statement which seem well off, you chose a figure of 100k years which is ~10 times longer than our current inter-glacial. This is fairly important as the size and volume of the glaciers covering the northern and southern hemispheres during the last ice age was huge. As they melted the water would have been very near freezing and possessing a greater density effectively sinking straight to the bottom dropping the deep ocean temperature significantly. The thermocline generally prevents convection mixing leading to conduction as the only applicable surface--> lower ocean level heat transfer and the same is true for the earth--> deep ocean transmission.
You may have however stumbled on one of the most interesting points at least for me. I recently did an essay on ocean acidification, I am currently working on one for nuclear power but more interesting to me and one of the fastest way to deconstruct the deep ocean cherry picking data set is a thorough process control analysis for a stepwise function. and while the ocean temperature change of a decade, assuming a well mixed system, may be ~.001 when I get the data from both Argos and ORAS4 that is an important amount of heat 6.98*10^17 KJ=6.98*10^20J which is a huge portion of the 2*10^23J cited by ORAS4.
Steven Burnett
Thank you for your interesting comment. I am the first to admit to being no expert on the science of the oceans. I am simply asking questions that I have never seen asked before. I struggle with the concept that polar cooling results in a uniformly cold deep ocean. I have never been able to find calculations and heat balances that support that theory. All we ever get is airy fairy hand waving. As you say because of the thermocline barrier to mixing, heat transfer from the mixed layer will primarily be by conduction and it will be into the deep ocean. Add to this the thermal energy conducted through the earths core and it adds up to an awful lot of energy to dispose of. Unless that energy is shed the oceans will warm at 1degC every 10,000 years. Current polar icecaps contain less than 1% of ocean water content. I doubt that even in the last ice age that ratio rose above 10%. If so that would not be enough to chill the oceans to 3 degC.
The number 6 x 10^17kj keeps cropping up all over the place. It is the approximate heat input from the earh's core. It also appears again in my part 2 in a seamingly unrelated aspect. I hate coincidences.
David Coe: "My question is where does that energy go if it doesn't heat the deep ocean?"
As I understand it, ocean bottom water, along with any geothermal heat it may acquire from the underlying crust, travels around the deep ocean basins along the 'oceanic conveyor belt' until it returns to the surface - some of it in the eastern Pacific - to restart the cycle as surface water. So geothermal heat only has the duration of one conveyor belt cycle (1000 years?) to warm the bottom water (by about 0.1C?).
David: Heat conduction into the deep ocean by conduction is almost certainly negligible. Although I can't claim any real expertise, tt is my understanding that some vertical mixing is caused when horizontal currents run over obstacle on the rough ocean bottom and create eddies in the vertical plane. In shallower areas, rising and falling tides can also produce vertical mixing. Salt content can also play a role, because work must be done to bring colder water up from the deep ocean and replace it with warmer water, but this is easier when the warmer water is saltier.
Everyone is currently speculating about the possibility that the "missing heat" is diffusing into the deep ocean, but little is known about this and no one seems to talk about how well or poorly climate models handle this problem. (Silence makes me suspect that the models do poorly.) There are some observation concerning how far CFC's have penetrated into the ocean since manufacture began and probably work with the pulse of C14 released by atmospheric testing of nuclear weapons.
Thanks for the response David. I found the paper thought provoking.
My argument was that mixing occurs with the Ferrel Cell and Polar Cells throughout the year that would tend to dissipate spatial differences in carbon dioxide concentrations between temporate and arctic zones that would arrise due to differential rates of production by decomposition. Essentially this is a dissipative Second Law type argument. I just don't think the Air in the Polar Cell is thermodynamically insulate from mixing with the air from temperate latitudes. There is a little more to this..
There is an argument that suggests that this transport of air between the temperate and Polar regions may actually be much more efficient in Winter. This is because in Winter Polar Cell boundary moves to substantially lower latitudes and extending its circulation and influence over the mid latitude continental land masses. This should make the rate of distribution of the winter temperate latitude carbon dioxide pulse to the poles more efficient (whilst making it less efficient to the tropics).
So where does the carbon dioxide at the poles come from - The Polar Cell is picking up carbon dioxide as it drives winds across the Temperate Northern Continental land masses (where winter decomposition is high) and returning it through the upper atmosphere to the air above the poles - with the efficiency of the process aided by the seasonal increase in the size and strength of the Polar Cell in winter.
As there is more high and mid latitude land in the Northern Hemisphere the theory makes the prediction that the carbon dioxide cycle would have a greater Northern Hemisphere amplitude than it would in the Southern Hemisphere.
"The deep ocean is bombarded from top and bottom by incoming heat fluxes and yet it is
uniformly cold. WHY, WHY, WHY?
After decades of research and the expenditure of tens of billions of dollars in research
funding, is our knowledge such that we cannot even ask, let alone answer the most basic of
questions involving our world?"
Simply because the pressure of the atmosphere on the ocean surface sets the value of the latent heat of vaporisation which in turn sets the rate at which energy can leave the oceans to the atmosphere above.
If the pressure of the atmosphere were greater then the temperature of the ocean bulk would be higher and vice versa for a given level of ToA insolation.
A full discussion can be found here:
http://www.newclimatemodel.com/the-setting-and-maintaining-of-earths-equilibrium-temperature/