This interesting essay by Dr. Spencer is reposted from his blog, link here:
Global Warming Causing Carbon Dioxide Increases: A Simple Model
May 11th, 2009 by Roy W. Spencer, Ph. D.
Global warming theory assumes that the increasing carbon dioxide concentration in the atmosphere comes entirely from anthropogenic sources, and it is that CO2 increase which is causing global warming.
But it is indisputable that the amount of extra CO2 showing up at the monitoring station at Mauna Loa, Hawaii each year (first graph below) is strongly affected by sea surface temperature (SST) variations (second graph below), which are in turn mostly a function of El Nino and La Nina conditions (third graph below):
Click for larger images
Click for larger image
During a warm El Nino year, more CO2 is released by the ocean into the atmosphere (and less is taken up by the ocean from the atmosphere), while during cool La Nina years just the opposite happens. (A graph similar to the first graph also appeared in the IPCC report, so this is not new). Just how much of the Mauna Loa Variations in the first graph are due to the “Coke-fizz” effect is not clear because there is now strong evidence that biological activity also plays a major (possibly dominant) role (Behrenfeld et al., 2006).
The direction of causation is obvious since the CO2 variations lag the sea surface temperature variations by an average of six months, as shown in the following graph:
So, I keep coming back to the question: If warming of the oceans causes an increase in atmospheric CO2 on a year-to-year basis, is it possible that long-term warming of the oceans (say, due to a natural change in cloud cover) might be causing some portion of the long-term increase in atmospheric CO2?
I decided to run a simple model in which the change in atmospheric CO2 with time is a function of sea surface temperature anomaly. The model equation looks like this:
delta[CO2]/delta[t] = a*SST + b*Anthro
Which simply says that the change in atmospheric CO2 with time is proportional to some combination of the SST anomaly and the anthropogenic (manmade) CO2 source. I then ran the model in an Excel spreadsheet and adjusted an “a” and “b” coefficients until the model response looked like the observed record of yearly CO2 accumulation rate at Mauna Loa.
It didn’t take long to find a model that did a pretty good job (a = 4.6 ppm/yr per deg. C; b=0.1), as the following graph shows:
Click for larger image
The best fit (shown) assumed only 10% of the atmospheric CO2 increase is due to human emissions (b=0.1), while the other 90% is simple due to changes in sea surface temperature. The peak correlation between the modeled and observed CO2 fluctuation is now at zero month time lag, supporting the model’s realism. The model explained 50% of the variance of the Mauna Loa observations.
The best model fit assumes that the temperature anomaly at which the ocean switches between a sink and a source of CO2 for the atmosphere is -0.2 deg. C, indicated by the bold line in the SST graph, seen in the second graph in this article. In the context of longer-term changes, it would mean that the ocean became a net source of more atmospheric CO2 around 1930.
A graph of the resulting model versus observed CO2 concentration as a function of time is shown next:
If I increase the anthropogenic portion to 20%, the following graph shows somewhat less agreement:
Click for larger images
There will, of course, be vehement objections to this admittedly simple model. One will be that “we know the atmospheric CO2 increase is manmade because the C13 carbon isotope concentration in the atmosphere is decreasing, which is consistent with a fossil fuel source.” But has been discussed elsewhere, a change in ocean biological activity (or vegetation on land) has a similar signature…so the C13 change is not a unique signature of fossil fuel source.
My primary purpose in presenting all of this is simply to stimulate debate. Are we really sure that ALL of the atmospheric increase in CO2 is from humanity’s emissions? After all, the natural sources and sinks of CO2 are about 20 times the anthropogenic source, so all it would take is a small imbalance in the natural flows to rival the anthropogenic source. And it is clear that there are natural imbalances of that magnitude on a year-to-year basis, as shown in the first graph.
What could be causing long-term warming of the oceans? My first choice for a mechanism would be a slight decrease in oceanic cloud cover. There is no way to rule this out observationally because our measurements of global cloud cover over the last 50 to 100 years are nowhere near good enough.
And just how strenuous and vehement the resulting objections are to what I have presented above will be a good indication of how politicized the science of global warming has become.
REFERENCES
Michael J. Behrenfeld et al., “Climate-Driven Trends in Contemporary Ocean Productivity,” Nature 444 (2006): 752-755.
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One more time–atmospheric CO2 is going up at 50% of the rate that CO2 is being added from fossil fuel combustion. If we assume that Spencer is right, and fossil fuels only account for 10% of the increase in CO2, then the rate of increase of CO2 in the atmosphere needs to be about 10X higher or we have radically over estimated the amount of fossil fuels that are being consumed. The CO2 needs to be going somewhere. If it is not going into the ocean, where is it going? Forests are being cut down in the tropics and are, perhaps, increasing in the Northern Hemisphere, but that would not account for the massive amount of CO2 that Spencer speculates is being released from the ocean–enough to dwarf the amount of CO2 being released from fossil fuels.
Spencer’s speculations need to take into account the data on CO2 fluxes. Someone should explain the error in my reasoning or you should show why the increase in CO2 in the atmosphere is understimated.
Also Nick,
“I note the oddity of this post’s assertion that ocean warming is the source of the regular annual rise in CO2, when just a few days ago we had another of many posts asserting that the oceans are cooling.”
This might have been fair comment if you hadn’t already accepted the illogicality of a warming sea being a net carbon sink. It appears that you only look for discrepancies in the skeptic storyline when the IPCC storyline contains far more. The cooling, by the way, is only over the last 6 years.
Furthermore, you might have noticed on this site that the Mauna Loa measurements had been showing suspicious drops until “errors” were corrected. In reality, like the other corrections of outgoing radiation, radiosonde, satellite and ocean buoys, all of which were adjusted towards the hypothesis, the real problem is that too many people are so certain of the hypothesis that they just don’t believe what their instruments are telling them. But the raw, unadjusted data are all consistent. As Douglass noted though, some of the “corrections” make the data inconsistent.
There is no such thing as “conservation of matter”.
Modern physics has shown, even in supposedly closed systems such as Earth’s atmosphere, that the only player is energy-mass equivalence. That is why Earth’s radiation budget is so important in determining climate.
BACKGROUND:
My paper was posted Jan.31/08 at
http://icecap.us/index.php/go/joes-blog/carbon_dioxide_in_not_the_primary_cause_of_global_warming_the_future_can_no/
Carbon Dioxide in Not the Primary Cause of Global Warming: The Future Can Not Cause the Past
Despite continuing increases in atmospheric CO2, no significant global warming occurred in the last decade, as confirmed by both Surface Temperature and satellite measurements in the Lower Troposphere. Contrary to IPCC fears of catastrophic anthropogenic global warming, Earth may now be entering another natural cooling trend. Earth Surface Temperature warmed approximately 0.7 degrees Celsius from ~1910 to ~1945, cooled ~0.4 C from ~1945 to ~1975, warmed ~0.6 C from ~1975 to 1997, and has not warmed significantly from 1997 to 2007.
CO2 emissions due to human activity rose gradually from the onset of the Industrial Revolution, reaching ~1 billion tonnes per year (expressed as carbon) by 1945, and then accelerated to ~9 billion tonnes per year by 2007. Since ~1945 when CO2 emissions accelerated, Earth experienced ~22 years of warming, and ~40 years of either cooling or absence of warming.
The IPCC’s position that increased CO2 is the primary cause of global warming is not supported by the temperature data. In fact, strong evidence exists that disproves the IPCC’s scientific position. This UPDATED paper and Excel spreadsheet show that variations in atmospheric CO2 concentration lag (occur after) variations in Earth’s Surface Temperature by ~9 months. The IPCC states that increasing atmospheric CO2 is the primary cause of global warming – in effect, the IPCC states that the future is causing the past. The IPCC’s core scientific conclusion is illogical and false.
There is strong correlation among three parameters: Surface Temperature (“ST”), Lower Troposphere Temperature (“LT”) and the rate of change with time of atmospheric CO2 (“dCO2/dt”). For the time period of this analysis, variations in ST lead (occur before) variations in both LT and dCO2/dt, by ~1 month. The integral of dCO2/dt is the atmospheric concentration of CO2 (“CO2”).
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See also Roy Spencer’s (U of Alabama, Huntsville) take on this subject at
http://wattsupwiththat.wordpress.com/2008/01/25/double-whammy-friday-roy-spencer-on-how-oceans-are-driving-co2/
and
http://wattsupwiththat.wordpress.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/
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Earlier work by Kuo et al reached similar conclusions about the lag of CO2 after temperature.
Coherence established between atmospheric carbon dioxide and global temperature
ref. Kuo C, Lindberg C & Thomson DJ, Nature 343, 709 – 714, 22 February 1990.
Summary:
The hypothesis that the increase in atmospheric carbon dioxide is related to observable changes in the climate is tested using modern methods of time-series analysis. The results confirm that average global temperature is increasing, and that temperature and atmospheric carbon dioxide are significantly correlated over the past thirty years. Changes in carbon dioxide content lag those in temperature by five months.
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Keeling et al reached some similar conclusions in 1995.
Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980
ref. C. D. Keellng*, T. P. Whorf*, M. Wahlen* & J. van der Plicht†, Nature Vol 375 . 22 June 1995
OBSERVATIONS of atmospheric C02 concentrations at Mauna Loa, Hawaii, and at the South Pole over the past four decades show an approximate proportionality between the rising atmospheric concentrations and industrial C02 emissions1. This proportionality, which is most apparent during the first 20 years of the records, was disturbed in the 1980s by a disproportionately high rate of rise of atmospheric CO2, followed after 1988 by a pronounced slowing down of the growth rate. To probe the causes of these changes, we examine here the changes expected from the variations in the rates of industrial CO2 emissions over this time2, and also from influences of climate such as EI Nino events. We use the 13C/12Cratio of atmospheric CO2 to distinguish the effects of interannual variations in biospheric and oceanic sources and sinks of carbon. We propose that the recent disproportionate rise and fall in CO2 growth rate were caused mainly by interannual variations in global air temperature (which altered both the terrestrial biospheric and the oceanic carbon sinks), and possibly also by precipitation. We suggest that the anomalous climate-induced rise in CO2 was partially masked by a slowing down in the growth rate of fossil-fuel combustion, and that the latter then exaggerated the subsequent climate-induced fall
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Veizer (GAC 2005) is very interesting, and was quite controversial when published – see also Veizer and Shaviv (2003):
Pages 14-15: The postulated causation sequence is therefore: brighter sun => enhanced thermal flux + solar wind => muted CRF => less low-level clouds => lower albedo => warmer climate.
Pages 21-22: The hydrologic cycle, in turn, provides us with our climate, including its temperature component. On land, sunlight, temperature, and concomitant availability of water are the dominant controls of biological activity and thus of the rate of photosynthesis and respiration. In the oceans, the rise in temperature results in release of CO2 into air. These two processes together increase the flux of CO2 into the atmosphere. If only short time scales are considered, such a sequence of events would be essentially opposite to that of the IPCC scenario, which drives the models from the bottom up, by assuming that CO2 is the principal climate driver and that variations in celestial input are of subordinate or negligible impact….
… The atmosphere today contains ~ 730 PgC (1 PgC = 1015 g of carbon) as CO2 (Fig. 19). Gross primary productivity (GPP) on land, and the complementary respiration flux of opposite sign, each account annually for ~ 120 Pg. The air/sea exchange flux, in part biologically mediated, accounts for an additional ~90 Pg per year. Biological processes are therefore clearly the most important controls of atmospheric CO2 levels, with an equivalent of the entire atmospheric CO2 budget absorbed and released by the biosphere every few years. The terrestrial biosphere thus appears to have been the dominant interactive reservoir, at least on the annual to decadal time scales, with oceans likely taking over on centennial to millennial time scales.
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I think there are perhaps four cycles in which CO2 lags T:
1. A cycle of thousands of years, in which CO2 lags T by ~hundreds of years (Vostok ice cores, etc.)
2. A cycle of ~70-90 years (Gleissberg), in which CO2 lags T by ~5-10 years (this is contentious – Ernst Beck’s direct-measurement CO2 data supports, ice core data does not, and there is the important question of how much humanmade CO2 affects this cycle).
3. The cycle I described in my paper of 3-5 years (El Nino/La Nina), in which CO2 lags T by ~9 months.
4. The seasonal “sawtooth” CO2 cycle, which ranges from ~18 ppm in the North to ~1 ppm at the South Pole.
It is clear that T precedes CO2 in cycles 1, 3 and 4. For Cycle 2 we have conflicting and perhaps inadequate data…
Regards, Allan
Bill DeMott (02:03:40) :
There is a basic reason why this analysis by Dr. Spencer cannot be published in a scientific journal. As alluded to in at least one posting above, his analysis either assumes that the law of the conservation of matter does not apply or that there are order of magnitude errors in our estimates of the amount of fossil fuels that is burned and/or the change in atmospheric CO2.
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Bill – this is Ferdinand Englebeen’s mass balance argument, and it is an interesting one. However, it is possibly wrong. Richard Courtney makes a strong counter-argument. This debate has been gong on between them for some time – you can probably find it by searching ClimateAudit or wattsup.
To put it into perspective, the annual natural variation in CO2 in the North is ~18 ppm, versus the annual average growth of CO2 in the atmosphere of ~2 ppm. Is it possible that nature does not even see man’s contribution?
Note that since 1958 there have been 12-month periods in which CO2 did not increase at all.
Annualized Mauna Loa dCO2/dt has “gone negative” a few times in the past (calculating dCO2/dt from monthly data, by taking CO2MonthX (year n+1) minus CO2MonthX (year n) to minimize the seasonal CO2 “sawtooth”.)
These 12-month periods are (Year-Month ending):
1959-8
1963-9
1964-5
1965-1
1965-5
1965-6
1971-4
1974-6
1974-8
1974-9
Has this not happened recently because of increased humanmade CO2 emissions, or because the world has, until recently, been getting warmer?
Bill DeMott (02:03:40) :
“What mass balance (conservation of matter) estimates tell us is that the rate of increase in atmospheric CO2 is about half the rate of CO2 release from burning fossil fuels.”
Where did you get this from? Please post a link or prove this. What are the error bars on this estimate?
By the way, remember from your undergraduate thermodynamics that matter is always conserved in chemical reactions: fuel+air –> products of reaction (which includes CO2, H2O, CO, …). I’m not sure why you would invoke “mass conservation” in this case…
Mike (03:33:53) :
A newcomer to this stuff.
Is there a network of reliable (i.e. properly audited for accuracy) CO2 measuring sites throughout the world?
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Have fun Mike.
Regards, Allan
Barrow Alaska
ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/brw/brw_01C0_mm.co2
Mauna Loa
ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/mlo/mlo_01C0_mm.co2
American Samoa
ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/smo/smo_01C0_mm.co2
South Pole
ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/spo/spo_01C0_mm.co2
Maybe this observation couldbe incorporated in this simple model?
http://icecap.us/index.php/go/joes-blog/co2_and_temperature_relationship_shown_questions_flat_ice_core_co2_graph_du/
If AGW was real science, this provocative analysis would be welcomed as a great way to test the durability and reliability of AGW.
Instead, since any questioning of AGW gets in the way of powerful financial and political agendas, the discussion will not happen.
Those new flash ads bring my browser to a very slow pace, forces me to view them, can’t scroll, can’t switch windows.
They are detestable.
Earth-bound stations measure outgassing rate in situ. They do not measure resultant global atmospheric CO2 levels. There are no stations that measure sinks (since by definition they want to measure CO2 it would be a waste of money to measure where CO2 is not). All other current statistics about how much CO2 we have in the atmosphere circling and swirling around the globe in globby loopy mists are modeled extrapolations. They are estimates based on for example, gas station receipts and rate of CO2 plant absorption in green houses. In addition, the data has not been collected long enough to cover multidecadal oscillations. AIRS did show that CO2 increased during the time the satellite was measuring this gas, but there were many other variables that increased at the same time. Correlation does not and did not point to cause and affect One thing AIRS has discovered so far is that CO2 is not well mixed in the atmosphere. If the modelers got that one wrong, they should be spending their time performing other tests of falsification instead of standing on their bandwagon picking their noses.
Oh! We are safe! Just tax Mauna Loa!!!
Another relevant thread is the old measurements of CO2 by chemical methods,
http://wattsupwiththat.com/2008/07/25/beck-on-co2-oceans-are-the-dominant-co2-store/
If it is relevant to have temperatures measured at the surface in a grid, it is relevant to measure CO2 also, the way we measure rainfall next to the temperature sensors, since such value is placed on CO2 and its effect on the weather. We would then see, as we see with humidity for example, whether temperatures are higher when CO2 is higher. After all this famous green house effect will be stronger the denser the air ( more molecules ppm).
Lindsay H (04:15:10) :
Water evaporates from the oceans in some places while rivers feed water into the oceans in other places; yet we observe that sea level is roughly the same everywhere. Hard to believe that all this water can flow around the world so quickly!
JFA: See if you can add NoScript to your browser, so you can better control what uses your browser. My browser isn’t having difficulty with these ads so I told NoScript to allow everything on this page, but it may help you. (I’m not using NoScript as an ad blocker, just as a security tool. If someone makes their site too hard to navigate without JavaScript then they have to hope that I feel it worth the trouble to allow JS.)
A graph which shows both temperature and CO2 changes might be helpful. On this, you can see that temperature rises before CO2 rises, and temperature drops before CO2 drops. The analysis by Spencer uses statistics to confirm that this happens, but with the two on the same graph you can see it yourself.
http://www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.2/plot/hadcrut3vgl/isolate:60/mean:12/from:1958
I seem to have not gotten the right image incantation.
http://lh4.ggpht.com/_Rr87nljGjX0/SgrthyWC3II/AAAAAAAAAB0/wDkUStP47_A/s512/wood_for_trees_temp_co2.png
Perhaps, I am missing something elementary here, but when Spencer uses the 90%-10% split ocean-anthropogenic isn’t he saying that changes in ocean temp *determine* 90% of the variation of in CO2 concentrations, not that 90% of the increased CO2 in the atmosphere came directly from the oceans.
As example, assume animals A and B live on an island. If animal A only eats animal B, then we could say that the population of A is determined by the population of B. Even if we (anthropogenically) parachuted As in by the thousands, they would still be ultimately be determined by the population of B(excess As simply die off).
Cheers, 🙂
The problem with Spencer’s ‘model’ is that he appears to have made a numerical error!
According to his graphs the present dCO2/dT ≃ 2ppm/yr
His best fit SST term is 4.6*SST, as the present SST anomaly is ~0.21 (from his graph) this gives dCO2/dT (from SST)≃ 0.97 or about half of the total this should mean that about half should be due to Anthro.
However he says that the Anthro term is 0.1*Anthro, since Anthro ≃ 4.2 dCO2/dT (from Anthro)≃ 0.42.
Clearly this is about 20% not 10% but clearly the equation as written doesn’t give the result as given in the graph, to do so would need a value for b of ~0.25 (about 50%). It’s possible that his equation for the Anthro term uses different units than presented in his graph but even so it’s inescapable that that term must yield about half the dCO2/dT not 10%.
So Spencer needs to go back to his spreadsheet and correct his math (and correct the description in his blog).
His model has flaws anyway, for example the SST term should at least have a dependence on [CO2] as well.
The CO2 cycle is very interesting, thank you Dr. Spenser for your time on this. I am still puzzling over this AIRS video, I’ll post a link below. This video shows that the highest annual concentrations of CO2 occur in April, approx. 40-60 deg. N. In the western hemisphere, it looks like Alaska and Canada are the big emmiters. This makes no sense to me, as things are just beginning to thaw from winter, from non-industrial, low-density habitation areas. The only thing I can imagine is a loss of snow and ice releasing CO2 from under the same. I suppose all the underwater and underground species have been respirating all winter, and that might be released.
http://tinypic.com/m/2l9dea/1%5DView My Video
Hmm. The PDO index also seems to lead the CO2 changes rather well.
http://www.woodfortrees.org/plot/esrl-co2/isolate:60/mean:12/scale:0.2/plot/jisao-pdo/isolate:60/mean:12/from:1958
AGW-ers:
The ocean is a net sink, no doubt, but the the interesting bit is what would the concentration have been without our emissions? It bothers me a little that the ocean becomes a source during strong ninos, and that there is not a widening gap between CO2 increase and temp graphs as the emissions increase.
counter-AGW-ers:
How do you explain this: http://en.wikipedia.org/wiki/File:Co2-temperature-plot.svg
and this: http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg
Temperature should have been 12 deg higher to explain the CO2 level, and you have to choose between a warm MWP or man-made CO2. You can’t have both MWP as warm as today and ocean as the source.
It seems, for me, a even more dangerous scenario that the warmer seas become a CO2 producer. If the hypotheses is correct, the antropogenic production will surely break the natural inbalance.
10% or 20% are very significant figures in a system.
The Monster (16:09:52) :
The long-term record shows that the CO2 changes trail the temperature changes by roughly 800 years. When I have tried to discuss this with True Believers, I’m told that there is a feedback process under which the changes are amplified by the increased release of dissolved CO2 from the higher temperatures, and I’m just too simple to understand the science, which has already dealt with fools like me, so shut up.
There is NO evidence that the rising CO2 causes any feedback. This is AGW bluster at its worst. This contains what you need to rebut it.
PaulHClark (23:03:16) : I found this a useful (and for me at least easy to read) piece when looking at CO2 and ocean carbon sinks – it also gives an explanation of Henry’s Law [Lubos Motl URL]
I’m very sorry to say Lubos has got it wrong AFAICT. He usually has my respect. The oceans hold a huge amount of CO2 and we therefore have every reason to suspect that atmospheric CO2 levels are very sensitive to small SST changes. Have a look at my page on CO2 and decide for yourself. The whole CO2 issue is an ever-changing mobile flux that is heavily dependent on the oceans and the biosphere and far less dependent on us to date. It is a strange coincidence that the rising CO2 rate is about half the emissions rate – but it is a coincidence that has mesmerised the whole of AGW.
Here are some useful figures (gigatons of carbon) to help get things in proportion:-
Atmosphere 700… Ocean “surface” 700… Biosphere 70… Total ocean 40,000… Fossil fuel reserves 12,000…
Annual natural flux 230… Annual human CO2 emissions 6…
The simple question is, would it help if there were no anthropogenic sources of CO2?
Another question would be – Will the adverse effects of global warming and climate change stop manifesting themselves if Al Gore went ahead and said there is no need to worry about fossil fuels since they have insignificant contribution to global CO2 levels?