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Carbon Dioxide in Atmosphere 5-15 Years Only

IF carbon dioxide emissions from fossil fuels only stayed in the atmosphere a few years, say five years, then there may not be quite the urgency currently associated with anthropogenic global warming.    Indeed it might be argued that the problem of elevated levels of atmospheric carbon dioxide could be easily reversed as soon as alternative fuel sources where found and/or just before a tipping point was reached.   The general consensus, however, is not five years, but rather more in the range of 50 to 200 years.     

But in a new technical paper to be published in the journal ‘Energy and Fuels’, Robert Essenhigh from Ohio State University, throws doubt on this consensus.   Using the combustion/chemical-engineering Perfectly Stirred Reactor (PSR) mixing structure, or 0-D Box, as the basis of a model for residence time in the atmosphere, he explains that carbon dioxide emissions from fossil fuels are likely to have a residence time of between 5 and 15 years.    He further concludes that the current trend of rising atmospheric carbon dioxide concentrations is not from anthropogenic sources, but due to natural factors.

Here’s the abstract:

The driver for this study is the wide-ranging published values of the CO2 atmospheric residence time (RT), , with the values differing by more than an order of magnitude, where the significance of the difference relates to decisions on whether: (1) to attempt control of combustion-sourced (anthropogenic) CO2 emissions, if >100 years; or (2) not to attempt control, if ~10 years.  This given difference is particularly evident in the IPCC First (1990) Climate Change Report where, in the opening Policymakers Summary of the Report, the RT is stated to be in the range 50 to 200 years; and, (largely) based on that, it was also concluded in the Report and from subsequent related studies that the current rising level of CO2 was due to combustion of fossil fuels, thus carrying the, now widely-accepted, rider that CO2 emissions from combustion should therefore be curbed.  However, the actual data in the text of the IPCC Report separately states a value of 4 years.  The differential of these two times is then clearly identified in the relevant supporting-documents of the report as being, separately: (1) a long-term (~100 years) adjustment or response time to accommodate imbalance increases in CO2 emissions from all sources; and, (2) the actual RT in the atmosphere, of ~4 years. As check on that differentiation, and its alternative outcome, the definition and determination of RT thus defined the need for and focus of this study.  In this study, using the combustion/chemical-engineering Perfectly Stirred Reactor (PSR) mixing structure, or 0-D Box, for the model-basis, as alternative to the more-commonly used Global Circulation Models (GCM’s), to define and determine the RT in the atmosphere, then, using data from the IPCC and other sources for model validation and numerical determination, the data: (1) support the validity of the PSR model-application in this context; and (2) from the analysis, provide (quasi-equilibrium) residence times for CO2 of: ~5 years carrying C12; and of ~16 years carrying C14, with both values essentially in agreement with the IPCC short-term (4-year) value, separately, in agreement with most other data sources and notably a (1998) listing by Segalstad of 36 other published values, also in the range 5 to 15 years.  Additionally, the analytical results then also support the IPCC analysis and data on the longer “adjustment time” (~100 years) governing the long-term rising “quasi-equilibrium” concentration of CO2 in the atmosphere.  For principal verification of the adopted PSR model, the data source used was outcome of the injection of excess 14CO2 into the atmosphere during the A-bomb tests in the 1950’s/60’s which generated an initial increase of approximately 1000% above the normal value, and which then declined substantially exponentially with time, with = 16 years, in accordance with the (unsteady-state) prediction from, and jointly providing validation for, the PSR analysis.  With the short (5-15 year) RT results shown to be in quasi-equilibrium, this then supports the (independently-based) conclusion that the long-term (~100-year) rising atmospheric CO2 concentration is not from anthropogenic sources but, in accordance with conclusions from other studies, is most probably the outcome of the rising atmospheric temperature which is due to other natural factors. This further supports the conclusion that global warming is not anthropogenically driven as outcome of combustion.  The economic and political significance of that conclusion will be self-evident.

*************

Notes

THE POTENTIAL DEPENDENCE OF GLOBAL WARMING ON THE RESIDENCE TIME (RT) IN THE ATMOSPHERE OF ANTHROPOGENICALLY-SOURCED CARBON DIOXIDE
by Robert H. Essenhigh,  Department of Mechanical Engineering, The Ohio State University, Columbus, USA. In press in the journal ‘Energy and Fuels’, but now available at ACS website http://pubs.acs.org/articlesonrequest/AOR-fAEJXMX3JgkNFmgAkdpu

Tom Quirk recently arrived at a similar conclusion using a different methodology, more here: http://jennifermarohasy.com/blog/2009/03/the-available-evidence-does-not-support-fossil-fuels-as-the-source-of-elevated-concentrations-of-atmospheric-carbon-dioxide-part-1/

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69 Responses to “Carbon Dioxide in Atmosphere 5-15 Years Only”

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  1. Comment from: John F. Pittman


    FE you state “”The flow of natural releases/sinks is not known, but the emissions and the increase in the atmosphere are known with sufficient accuracy over the past 50 years. “”

    Yet the estimate of how long it would take such as, on the order of 40 years, depends on knowing that flow or rate. Thus, the 40 year estimate is based on assuming it is constant, IIRC. Also, IIRC, the estimate of 100+ years depends on the unmeasured assumption that the sinks will be less effecient.

    So, it is not a matter of simple bookkeeping. And looking at the year by year change of the carbon balance it is hard to tell about those unmeasured quantities.

    Take for example: assume that the natural rate has slowly been increasing for 300 years. Next assume that it increases suddenly. From an unmeasured point of veiw, it would be claimed that the sinks had been exhausted. Yet that would not be true. Or the converse, assume that the world’s ecosystem has a lag and that it starts consuming CO2 twice as fast, one would not know if it was the sink increasing or the natural rate declining. The year by year rate could and has been trending. Do you know of a good paper on this? When I did it with what I could find on decade numbers, it indicated that the sinks were inceasing (or the natural flux was declining).

    Though I agree with the CO2 having increased by man’s input as can be easily seen with your difference equation. I am not in agreement that the CO2 measurements are correct.

    You state “”Thus I have no knowledge of any manipulation of the data of ice cores, and I have reasonable confidence in the CO2 (and other) data the ice cores show. If you have any proof of manipulation, or the real migration of CO2 out of the ice cores at -20 to -40°C, I am willing to consider that.”" I have no knowledge either of ice core manipulation nor do I have knowledge of manipulation of the “wet” chemistry measurements of CO2 that disagree with the ice core data. I do know however, that diffusion occurs in that I have been having to deal with it professionally for over 25 years in one form or another. Whether it makes a difference over the short-term unlikely. Over the long term, well it is modelled and I have used it successfully, as a function of temperaure^1.76. Power laws and centuries for t (time) do not give me confidence in the claims of no diffusion.

    If we only had to deal with CO2 for one day I would be in agreement. But that is not the case.

  2. Comment from: Ferdinand Engelbeen


    John F. Pittman April 19th, 2009 at 9:43 pm

    “Yet the estimate of how long it would take such as, on the order of 40 years, depends on knowing that flow or rate. Thus, the 40 year estimate is based on assuming it is constant, IIRC. Also, IIRC, the estimate of 100+ years depends on the unmeasured assumption that the sinks will be less effecient.”

    Forget for the moment the 100+ years, that is the IPCC scale after enormous releases of CO2 from burning all available oil and a lot of coal. The 40 years half life indeed is based on current sink rates, which are relative constant over the past 50 years (a little more coarse over the period 1900-1960, based on ice cores), the increase in the atmosphere is about 53% of the emissions:
    http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
    Thus, indeed the sinks are increasing, in ratio with the emissions (which is the case if the “old” equilibrium sink/source process acts as a simple first order process).

    The (small) variability around the trend (thus the increase ratio) is mainly temperature induced, but with a maximum influence of 8 ppmv/°C, that doesn’t play much role over relative small temperature changes (except if we are plunging into a new ice age…). Of course, it is always possible that the ratio changes, but this is a ratio which is near fixed over the past 800,000 years…

    Compared to the surface temperature measurements, the current CO2 measurements are a dream for any scientists: the calibration procedures are quite rigorous and are an example of how to do that for any type of measurement. See the MLO procedures (the same procedures are in use for all baseline stations):
    http://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html

    For ice core CO2 measurements, there are a few more problems to overcome, and handling of the ice core is crucial to avoid huge deviations. But even there, the old wet methods (at best +/- 10 ppmv) were no match for the current ice core accuracy (+/- 1.2 ppmv). The main problem with the old methods is not the accuracy but where was measured: measurements over the sea and several coastal places overlap with the ice core CO2 levels. Measurements over land near huge sources/sinks still overlap in range but the diurnal range is extreme (250-600 ppmv is no exception), where the averages are completely biased to higher values, but still the ice core values are above the minima. See more about Beck’s historical data at:
    http://www.ferdinand-engelbeen.be/klimaat/beck_data.html

    A question to you: there is much more migration in sea ice (by salt inclusions) and in ice near melting point (as often is the case for mountain glaciers). For what kind of ice is your migration experience?

  3. Comment from: Tom L


    RW wrote… “1. Why did this ‘natural source’ of CO2 start pumping it out just when mankind started producing CO2 in significant quantities?”

    A question that you should be asking yourself is this. Since we know that 93% of all of the CO2 is in the ocean vs. 2% in the atmosphere, since the ocean/earth has gotten warmer since 1930, reqardless of the driver, why would you expect CO2 to have not increased. As sea water warms, it expells CO2.. No one questions that. Since the time when intense global industrialization really started to kick off – 1930 or so – the amount of atmospheric CO2 has increased at an average rate of only 1 ppm/year. Since the ocean contains 50 times more CO2 than the atmosphere, the slightest warming of the ocean would easily expell enough CO2 to account for most of that 1 ppm. This has certainly occured after nearly every past global warming period.

    I would think that the question you should be asking is how much of the increase in global CO2 is likely the result of oceanic warming.

    As for where the anthropogenic CO2 has gone, look at the carbon cycle. What goes up must go down and back into the earth. CO2 is 30 times more soluble in salt water and 70 more soluble than N2, so CO2 is removed more quickly than is Oxygen and Nitrogen. The carbon cycle is atmospheric CO2 enters the ocean as dissolved CO2. Much of it than becomes carbonic acid, which than unites with CA, Mg, and numerous other atoms to form various forms of caronates, mostly coral. Coral than morphs into limestone. That’s where your mankind CO2 end up!

  4. Comment from: eric adler


    Comment from: Tom L April 20th, 2009 at 4:07 am


    RW wrote… “1. Why did this ‘natural source’ of CO2 start pumping it out just when mankind started producing CO2 in significant quantities?”

    A question that you should be asking yourself is this. Since we know that 93% of all of the CO2 is in the ocean vs. 2% in the atmosphere, since the ocean/earth has gotten warmer since 1930, reqardless of the driver, why would you expect CO2 to have not increased. As sea water warms, it expells CO2.. No one questions that. Since the time when intense global industrialization really started to kick off – 1930 or so – the amount of atmospheric CO2 has increased at an average rate of only 1 ppm/year. Since the ocean contains 50 times more CO2 than the atmosphere, the slightest warming of the ocean would easily expell enough CO2 to account for most of that 1 ppm. This has certainly occured after nearly every past global warming period.

    I would think that the question you should be asking is how much of the increase in global CO2 is likely the result of oceanic warming.

    As for where the anthropogenic CO2 has gone, look at the carbon cycle. What goes up must go down and back into the earth. CO2 is 30 times more soluble in salt water and 70 more soluble than N2, so CO2 is removed more quickly than is Oxygen and Nitrogen. The carbon cycle is atmospheric CO2 enters the ocean as dissolved CO2. Much of it than becomes carbonic acid, which than unites with CA, Mg, and numerous other atoms to form various forms of caronates, mostly coral. Coral than morphs into limestone. That’s where your mankind CO2 end up!

    Only 1/2 of the CO2 of human origin ends up absorbed in the oceans or land. The other half ends up in the atmosphere. Comparison of the annual amount emitted by man, 8 Gtons, with the total increase in amount of CO2 in the atmosphere, 4 Gtons, shows that.

  5. Comment from: John F. Pittman


    CO2/ fresh water.

  6. Comment from: RW


    Tom L – it’s really boring hearing the same nonsense time after time, from people who obviously haven’t bothered to do the slightest bit of research. It’s idiotic to form opinions on scientific matters without doing research first.

    The rise in CO2 is not due to oceanic outgassing. CO2 concentrations in the oceans are also rising.

    Quite simple, really. If you’d even bothered to read this thread, you’d see some detailed workings from Ferdinand Engelbeen which demonstrate this clearly.

  7. Comment from: Ferdinand Engelbeen


    Tom L April 20th, 2009 at 4:07 am

    [i]“I would think that the question you should be asking is how much of the increase in global CO2 is likely the result of oceanic warming.”[/i]

    That is known for short term (oceans + vegetation): about 3 ppmv/°C around the current trend, with a lag of one to a few months. For very long term (oceans + ice sheets + vegetation): about 8 ppmv/°C between glacials and interglacials with a lag of 600 years to several thousands of years.

    Thus with the 1°C or so temperature increase since the Little Ice Age of 400 years ago, the maximum result of the warming is 8 ppmv CO2 increase, while there is a 100+ ppmv increase since the start of the industrial revolution, of which 60+ ppmv since 1960…

    Further, one need to take into account that quantities in a reservoir are not important: even if the (deep) oceans contain much more CO2 (in different forms) than the atmosphere, there is only exchange with the atmosphere if there is a pressure difference: if the CO2 pressure in the oceans is higher than in the atmosphere (at the warm equator and during summer in mid-latitudes) more CO2 is released to the atmosphere, more is absorbed near the poles and winter in mid-latitudes. The average is about 7 microatmosphere more CO2 pressure in the atmosphere than in the ocean surface, thus more CO2 is absorbed than released by the oceans, despite increased temperatures. See Feely e.a.:
    http://www.pmel.noaa.gov/pubs/outstand/feel2331/exchange.shtml

  8. Comment from: Author


    With the number of responses evidently now topping out (at 57) I thought that some short terminating comments might be in order. Regarding the questions raised, many or most will be seen to be answered by the full article that will be available when the next E&F issue is formally published – or which you can get immediately if you log in to ACS: this might be worth doing to be able in the future to keep track of articles being continuously published in E&F (and other ACS journals) on CO2 and on the atmosphere (check out past E&F issues in the library). On the matter of independent Climate Drivers (comment 14), this is looked at in this “Viewpoint” article http://pubs.acs.org/subscribe/journals/ci/31/special/may01_viewpoint.html if you can call it up. Finally, on the broader factor of which gases are GHG’s, the answer is: primarily water, at about 80%, with CO2 minor, at about 20% (and a 1% balance of other generally insignificant gases because of their low concentration and/or low optical absorbtivity/emissivity). So what’s the big deal about combustion-sourced CO2? Some of this is in this article: Essenhigh, R.H.: “Prediction of the Standard Atmosphere Profiles of Temperature, Pressure, and Density with Height for the Lower Atmosphere by Solution of the (S-S) Integral Equations of Transfer and Evaluation of the Potential for Profile Perturbation by Combustion Emissions: Energy & Fuels 2006, 20, 1057-1067. [available in any qualified technical library].

    Hope this may resolve some of the questions

  9. Comment from: peterd


    I am not sure who “Author” is here, but I find the responses to the various criticisms of the Essenhigh article, or abstract, to be rather cavalier. (“The questions are answered in the published article”? In my own experience using a good technical library at my closest university, journals such as this one are not always available. I have just wasted time trying to access the full article at ACS, but as Nick Stokes noted at the very start of the discussion, it is not accessible to non-subscribers; why waste readers’ time sending them in pursuit of material that they cannot read?)
    First, on the question of “independent Climate Drivers”, the reader might like to consult the response made to the earlier (2001) Viewpoint article by Ole John Nielsen: http://pubs.acs.org/subscribe/journals/ci/31/i12/html/12box.html

    Second, the Viewpoint Essenhigh article linked above by “Author” was based, in part, on an astonishing mis-reading of the Mauna Loa seasonal CO2 variations (not “oscillations”), a mis-reading that was perpetuated in Essenhigh’s responses to two published criticisms of his article, in Chem. Innov. For the record, and to try and straighten this out one last time, at Mauna Loa CO2 levels peak in autumn and winter, then fall again, beginning around April, or early spring. See the data here: http://www.esrl.noaa.gov/gmd/ccgg/trends/
    As the climate warms through spring and early summer, the CO2 falls. Now, if is being suggested that warming oceans are the cause of global atmospheric CO2 increase, it becomes hard to reconcile this with the Mauna Loa data: as the oceans around Hawaii warm, and release CO2, the atmospheric CO2 should increase, which is precisely the opposite to what is observed at Mauna Loa in the northern summer, as pointed out in the two published responses. The Mauna Loa seasonal behaviour is inconsistent with the hypothesis of warming oceans as source of global CO2 increase. It appears that Essenhigh is totally confused about this.

    Third, “Author” above appears to claim that water vapour contributes about 80% to the total greenhouse effect, CO2 20%, and other GHGs can be ignored. In Essenhigh’s 2001 Viewpoint article, in Chemical Innovation, linked above, the number attached to water’s greenhouse contribution is given as 95%. So, which is it: 80% or 95%? In fact, neither figure appears to be very accurate, “on average”, and the role of GHGs other than water vapour and CO2 is downplayed.
    His data for water vapour is represented as some kind of Great Discovery, implying that atmospheric scientists have not recognized the importance of water vapour in the atmospheric radiative processes. Nothing could be further from the truth. Writing in Contemporary Physics, Sir John Mason stated that “. . . total net absorption [of infrared radiation] over the whole globe is about 75 × 1015 W, an average of 150 W/m2, roughly one-third by CO2 and two-thirds by water vapor” (Mason, B. J. Contemporary Physics, 1995, 36, 299–319). In the article by Kiehl and Trenberth mentioned in earlier posts here by Michael Hammer, those authors state: “For the clear sky, water vapor contributes to 60% of the total radiative forcing, while carbon dioxide contributes 26% to the clear sky radiative forcing.” Nothing in Essenhigh’s reasoning persuades me that these other estimates calculations for the contribution due to water vapour, taken from line-by-line calculations- are wrong.

  10. Comment from: peterd


    Correction: Sir John Mason stated that “. . . total net absorption [of infrared radiation] over the whole globe is about 75 × 10^15 W

  11. Comment from: Author


    In (partial) reply to Mr. peterd first let me say that comment, even if “alternative”, is still appreciated as it says that someone is listening, even if they don’t agree; but that can be resolved by discussion.

    On the first point. regarding web access to the paper, this is something I have no control over as it is set by ACS. Web posting ahead of journal publication is evidently the new style and I think we are going to see more of it from all journals. I can say that my copy of the “current” (March-April) issue of Energy & Fuels recently arrived so the next, May-June, issue should be within the next 2 months or so, and I expect to see my article in that issue; and if the university library that peterd goes to is a good one it will have Energy & Fuels. He can check that right away to see if it has past copies. Next, moving on to the Nielsen commentary that he cites, read my replies to that at the end of his commentary and you will find answers. I don’t think I need to say more on that one.

    On point 2, regarding the Mauna Loa oscillations (i.e., moving regularly up and down: and if that’s not an oscillation, I don’t know what is): the graphs clearly show that the levels peak in (late) spring, and bottom out in the fall. But (coming out of some partial background in geology as a component of my original Tripos degree in Natural Sciences at Cambridge) I have always understood that the sea temperatures round Hawaii were largely controlled by the sea currents moving from south(west) to north(east) so that – unexpectedly back-to-front – they were cool in the (northern) spring and warmer in the summer, which could then account for the CO2 oscillation driven by the sea emissions/removals. This could still be open-ended, but in the context of the overall matter of GW it is essentially on the side and can be taken out of the discussion for the time being. It doesn’t directly affect the main focus of the argument though it does remain an interesting point.

    On point 3, regarding the change in (average) water concentration in the atmosphere, this was changed in the (cited) 2006 E&F article for reasons given, essentially to take into account the more rapid drop in water concentration with altitude than with the other gases (particularly, of course, CO2). But this still didn’t alter the final conclusions. Additionally, the factor of including water as a major GHG does have substantial background — but only in some sources. As alternative for example, there is Rotman’s book: “IMAGE: Integrated Model to Assess the Greenhouse Effect” (Kluwer: 1990) which completely excludes water as a GHG! And check out what you can of the radiation models. Water is very often minor – or omitted. The moment you properly add it in, CO2 then becomes minor (at about 20%), and adding in the factor that 95% of CO2 is from natural sources and only 5% from combustion, then for the total, 5% of 20% is 1%. That’s significant?

    Mr. petard, if you can’t access the 2006 E&F article and would like to check it, I can send you the article if you send me an e-mail address. This is mine: essenhigh.1@osu.edu.

  12. Comment from: Bernard J.


    On 24th April 2009, at 6:28 pm, peterd said:

    “For the record, and to try and straighten this out one last time, at Mauna Loa CO2 levels peak in autumn and winter, then fall again, beginning around April, or early spring…
    As the climate warms through spring and early summer, the CO2 falls. Now, if is [sic] being suggested that warming oceans are the cause of global atmospheric CO2 increase, it becomes hard to reconcile this with the Mauna Loa data: as the oceans around Hawaii warm, and release CO2, the atmospheric CO2 should increase, which is precisely the opposite to what is observed at Mauna Loa in the northern summer, as pointed out in the two published responses. The Mauna Loa seasonal behaviour is inconsistent with the hypothesis of warming oceans as source of global CO2 increase. It appears that Essenhigh is totally confused about this.”

    Except that Essenhigh is not confused, and peterd is.

    A cursory bit of fact-checking at the 6th grade level would hit sources such as:

    http://en.wikipedia.org/wiki/Keeling_Curve

    which quite nicely explains what is common knowledge, and trivial science…

    “The Keeling Curve … shows a cyclic variation of about 5 ppmv in each year corresponding to the seasonal change in uptake of CO2 by the world’s land vegetation. Most of this vegetation is in the Northern hemisphere, since this is where most of the [planet's] land is located. The level decreases from northern spring onwards as new plant growth takes carbon dioxide out of the atmosphere through photosynthesis and rises again in the northern fall as plants and leaves die off and decay to release the gas back into the atmosphere.”

    For the record, peterd, you are the party that requires ‘straightening out’.

    Big oopsadaisy, huh?

  13. Comment from: Ferdinand Engelbeen


    Robert Essenhigh,

    The main problem with your (and Segalstad’s and many others) approach is that the residence time (of about 5 years) of any molecule in the atmosphere (whatever the origin) has nothing to do with the excess life time of any additional CO2 (whatever the origin) injected in the atmosphere (which is about 40 years).

    The first is about how much CO2 molecules in the atmosphere are exchanged with CO2 from vegetation/oceans (about 150 GtC of 800 GtC) within a year over the seasons. The second is how much CO2 as mass is removed each year from the atmosphere into the other reservoirs (currently about 4 GtC/yr of 800 GtC). Thus while the first is about where the molecules CO2 reside (the quality), the second is about what the mass balance shows (the quantity).

    In your PSR example, if you add a small stream of red colored liquid to a PSR where 100 time more other (colorless) flows are added and removed (in equilibrium at start position). The 5 years residence time is about what the fate is of the color in the PSR, the 40 years residence time is about what the level in the reactor does if you stop the addition after a while.

    Even if 95% of all current CO2 is natural and only 5% human (due to year by year exchanges of molecules), that doesn’t change the fact that over 90% of the increase in mass (100+ ppmv) since the industrial revolution is caused by human emissions (maximum 10% by the temperature increase since the LIA), because nature (at least in the past 50 years) has always been a net sink of CO2. Thus the realistic influence of humans on the total radiation balance is about 7% (+30% CO2).

    If that has any (disastrous) consequences, that is a complete different question…

  14. Comment from: Ferdinand Engelbeen


    Robert Essenhigh,

    I have read your Viewpoint now, I don’t know how I did reach it, previous attempts failed…

    There are a few points where I differ in opinion:

    “The numbers are instructive. In 1995, the Intergovernmental Panel on Climate Change (IPCC) data on the carbon balance showed ~90 gigatons (Gt) of carbon in annual quasi-equilibrium exchange between sea and atmosphere, and an additional 60-Gt exchange between vegetation and atmosphere, giving a total of ~150 Gt (3). This interpretation of the sea as the major source is also in line with the famous Mauna Loa CO2 profile for the past 40 years, which shows the consistent season-dependent variation of 5–6 ppm, up and down, throughout the year—when the average global rise is only 1 ppm/year.”

    The point is that there is zero effect of the seasonal changes, as long as there is no change in average temperature. The effect of average temperature on the CO2 levels is small: currently 3 ppmv/°C around the trend, up to 8 ppmv/°C for the previous 800,000 years of glacials/interglacials. The latter includes long term changes in ocean currents and land ice/vegetation cover.
    Thus the increase of about 1°C since the LIA can’t have added more than 8 ppmv of the 100+ ppmv rise…

    And indeed as PeterD said, the seasonal variation is opposite to the general trend: warmer ocean degassing and vegetation growth are in opposite directions, where the summer growth encompasses the ocean degassing.
    Further, the average global seasonal variation (+/- 5 ppmv or +/- 10 GtC) is of the same order as the emissions (currently about 9 GtC), but the latter is one-way addition, the former only a cycle…

    Another point:
    “but no such profile with that [note: seasonal] amplitude is known to have been reported at any mainland location.”
    Please have a look at the seasonal profile of Schauinsland (now defunct):
    http://cdiac.ornl.gov/trends/co2/graphics/schauinsland.gif

    Next point:
    “the CO2 contribution to the atmosphere from combustion is within the statistical noise of the major sea and vegetation exchanges, so a priori, it cannot be expected to be statistically significant;”
    This is not true: The noise of the year-by-year (mainly temperature related) variability in natural sink capacity is +/- 2 GtC, while the average increase is + 4 GtC and the emissions are around +9 GtC. For every year in the past 50 years, nature was a net sink for CO2 and the average CO2 level increase is around 55% of the emissions. Even after 2-3 years already statistically significant above the noise caused by temperature (and precipitation). See:
    http://www.ferdinand-engelbeen.be/klimaat/klim_img/dco2_em.jpg

    And compare the accumulated emissions with the accumulation in the atmosphere:
    http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
    or temperature with the accumulation in the atmosphere:
    http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_1900_2004.jpg
    Which one is the cause of the increase of CO2 in the atmosphere…

    More reasons why humans are to blame for the CO2 increase:
    http://www.ferdinand-engelbeen.be/klimaat/co2_measurements.html

    But again, that humans are responsible for the CO2 increase doesn’t tell us anything about the impact of the increase on temperature/climate…

  15. Comment from: peterd


    Bernard P: I do not understand what point you are trying to make. The Wikipedia link you have given makes- in a different way, through explicit mention of the terrestrial growth and decay cycles- the same point I had tried to make. The seasonal CO2 variation around Mauna Loa is dominated by terrestrial uptake and release, not by the oceans, as Professor Essenhigh appears to claim. Essenhigh explicitly claimed, in his original Viewpoint article- and by providing the link back to it, I assume he still endorses his original arguments- that…“[i]n the literature, this [~5ppm seasonal] oscillation is attributed to seasonal growing behavior on the “mainland.” ” Essenhigh then went on to question this, asserting that “…there is lack of evidence for such behavior.” As Ferdinand Englebeen has noted separately here, there is abundant evidence for the influence of terrestrial growth and decay cycles on the CO2 variations.
    All of this is not to say, of course, that outgassing from the warm oceans does not occur. There is, however, good evidence that outgassing from warm oceans does not dominate the overall net oceanic uptake and the CO2 variations.
    We know that southern hemisphere CO2 “oscillates” with a much lower amplitude than does the northern hemisphere, only 2 ppmv or so, compared with 5-6 ppmv in the northern. If the oceans dominate the CO2 signal, then why is that variation so much smaller in the SH? After all, oceans are a much larger fraction of the SH than they are of the NH. The reason is, of course, the influence of terrestrial processes. (Most of the forests are in the NH, most of the ocean area in the SH.) The evidence is of a piece: the total CO2 data and d13C data fit together to support the notion that the terrestrial cycles dominate the seasonal variation, in the NH. “These data, therefore, indicate that the seasonal trend in [CO2] concentration observed in the northern hemisphere is the result of the activity of land plants.” (C.D. Keeling, Tellus, 12(2), 1960)

  16. Comment from: peterd


    Response to Professor Essenhigh:
    (1) E&F is available at my local (good) university library. But I must go there.
    (2) I will continue to chip away at the interpretation of the Mauna Loa data. In my first post here, I claimed that “…at Mauna Loa CO2 levels peak in autumn and winter, then fall again, beginning around April, or early spring.” I based my claim about the decline from April on a too-hasty inspection of the weekly Mauna Loa data, which are accessible somewhere within the NOAA site I linked. I cannot find that data quickly enough now, but I have the full data set through 2001 copied into an Excel sheet. In fact, a closer inspection of those weekly data indicates that the Mauna Loa maximum occurs more usually in May than in April, so “late spring” rather than “early spring” would be a more appropriate description. My mistake. However, the basic point remains: from May through September, when Mauna Loa CO2 is decreasing, the northern oceans are warming. So, how can the NH oceans’ warming be the major, or sole, cause of the fluctuations? (By the way, I still profess an aversion to the term “oscillation”, which I do not see used in the specialised literature. To me, the word implies a higher degree of regularity in the variations than does in fact exist; one thinks of those highly regular behaviours we all studied in high school physics. Such “oscillation” as exists is superimposed on a changing baseline. But this is just a quibble.)
    (3) I do not have home internet at the moment and any comments here must be made during my lunchtime (or out of!) work hours. My more detailed response to follow later.

  17. Comment from: Ferdinand Engelbeen


    peterd and prof. Essenhigh,

    The Mauna Loa data at 3,400 m show a delay and a smaller amplitude compared to near ground data like at Barrow or Alert. That was already noticed in the 1960′s by Bert Bolin (Sweden), where CO2 levels between ground level and altitude (from regular flights) were compared:
    http://www.ferdinand-engelbeen.be/klimaat/klim_img/seasonal_height.jpg

    The d13C variations are just opposite to the CO2 trends, which shows that vegetation is the dominant force of the CO2 variation over the seasons.

    The “cleaned” monthly data up to 2007 can be downloaded from the CDIAC web site:
    ftp://cdiac.ornl.gov/pub/trends/co2/
    up to date monthly data for Mauna Loa and “global” CO2 levels are at:
    ftp://ftp.cmdl.noaa.gov/ccg/co2/trends/
    And uncorrected hourly averages based on 40 minutes raw voltages of four baseline stations are at:
    ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/
    Where you can find daily and monthly “cleaned” averages too.

  18. Comment from: David Neisen


    Gentlemen and ladies, thank you for your spirited discussion regarding CO2, its causes and effects on and to the planet. As an interested party with NO scientific background, I have been able to understand and educate myself on this issue through your discussions. Apparently the science is not as Finalized and Determined as Mr. Gore would lead us chattering class to believe.
    I entered this comment to thank you all for furthering this debate and the scientific research on these types of issues. I thought I would download all of the comments and send them to friends so they too could learn from you… but I doubt they would spend the time to read pass the opening article.
    Thank you again, for allowing me to peek into your world to try and better understand our world.

  19. Comment from: Climate-gators at Copenhagen « The Tizona Group


    [...] models. The red lines are the models, the green lines are the observed data. Anyway, it probably doesn’t stay in the atmosphere for long [...]

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