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.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Lets see. The six month lag shown in the plots above, is rate of change of CO2 per year and temperature anomaly per year. Neither have the scale of the effect there, and there is not obvious way to know if the scale of the effect is the same when the absolute temperature is -30C as when it is 30C. We can only guess. There might be a logarithmic dependence, or an exponential one for all we know.
I wonder if one took the measured values in the antarctic of temperatures and CO2 whether the effect of the plots above would be seen? Certainly antarctic CO2 has a smaller amplitude change due to seasonal variations.
My guess: Ice core records come from regions where there is ice, i.e. below 0C where there is no flora, so only the cold ocean bubbling mechanism will dominate for shorterm effects. How much in ppm C02 comes out when going from -30C to -10C? It might still follow temperature, but be too small to count. One would have to wait for the deep ocean rich in CO2 turnover to get an effect.
Joel Shore (12:02:13) :
**There is no evidence that I know of that this is the case. In fact, the dependence of temperature on concentration is expected to be approximately logarithmic…which is why people talk about how much change is produced by a doubling of concentration. (For a logarithmic function, the amount of change due to each doubling is a constant.)**
“The amount of change due to each doubling is a constant”
What does this mean? When you check the graph the change decreases significantly with each doubling.
Check slide 22 of David Archibald’s paper at:
http://www.davidarchibald.info/papers/Solar%20Cycle%2024%20-%20Implications%20for%20the%20Unites%20States%20David%20Archibald%20March%202008.pdf
anna v
I showed some plots of Greenland ice cores on the other thread. You pointed out the CO2 AIRS animations
http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/
Greenland is experiencing more or less the same range of changes of CO2 as the rest of the NH but for shorter times. So CO2 from these cores can reflect the temperate zone levels.
When you talk about temperatures of -30C this is not the temperature of the whole globe and vegetation would still be in abundance further south.
Paul Vaughan (12:50:17) :
Time-integrate monthly dCO2/dt at varying bandwidth (i.e. 1mo, 2mo, 3mo, 4mo, …). Note particularly what happens at multiples of 12. Consider related insight in conjunction with George’s & Leif’s comments.
I take it that you have done this and could share you results and conclusions? I would have thought that the accurate record is insufficienltly long to obtain much useful info – but prove me wrong.
I’m not sure what you are saying about leif and george’s comments. There are many ice cores, some have good resolution early on gradually getting worse as shear and compression take their toll. At end of first iceage the granularity is about 150years. Should show up rises in co2 similar to the current
“”” bill (11:51:36) :
George E. Smith (10:14:38) :
My understqanding is that the ice cores are not exactly like tree rings where each individual year can be isolated uniquely. So my guess is that the faster changes are being integrated by the nature of the resolution of the ice layers. The process Roy is asserting is beyond ice core resolution (I believe)
No – the entry into / out of an ice age should create a visible shift in the CO2 concentration easily within the measurement limits of ice cores
There should be a near instantaneous change in co2 when the temperature changes maintained at least for the time the temperature is changing or as I would expect a permanent step change until the temp returns to normal.
There is NONE – why? “””
I thought we were talking about resolving the six months or less time lag that Dr Spencer was talking about.
But if Leif Says that each single year can be positivlely identified (or implies that) well that’s good enough for me. All the tv programs I have seen on ice cores seemed to suggest that wasn’t that clear; but then that’s TV for you. I’ve got a Scientific American Article from fairly recent years that shows two Antarctic ice cores that over the last 1000 years show CO2 and temperature data going in exactly the opposite directions in the two cores.
So much for ice cores as a global indicator. It was in an article in which the author claimed that man started global warming 8000 years ago and stopped an ice age in its tracks.
Speaking of CO2 in the oceans; my CO2 expert at Scripps, says that only about 15 of dissolved CO2 is in the from of CO2, and that most appears as either HCO3- or CO3- – ions.
So a question for the Physical Chemists (which excuses me) what part of that mix, of CO2/CO3- -/HCO3- is in equilibrium with 385 ppm of CO2 in the atmosphere under the direction of Henry’s Law (and I do mean under equilibrium conditions) recognizing that real world may not be equilibrium.
I’m wondering whether Henry’s Law sets the CO2 gas in solution of whether it sets the total including the ionic species; or something else entirely.
I presume that when the water freezes, that all three species are largely excluded from the ice, but I wonder how much of that must then exit to the atmosphere.
If the wild 18 ppm swing of CO2 in the arctic is biological as in permafrost peat bogs outgassing; why would those sources then take up the CO2 again, and wouldn’t those bogs give off CO2 while in the molten state, whereas the ocean gives up CO2 while freezing.
Enquiring minds want to know.
George
Ice core data gives about 40 year temp resolution and as said above 150 year CO2 at 12000 years ago.
These are the published data. Perhaps yearly info is available.
The general statement in this blog is that there is a 800year(ish) lag of CO2 from temperature hence there is no way CO2 controls temperature. This article suggest that the lag is 6 months. This disparity needs an explanation.
George,
I expect your shift key failed, and you meant 1%, which is about right. As I recall, it’s about 1% CO2, 88% HCO3- and 11% CO3–.
And yes, it’s the 1% that is in equilibrium with gas CO2. But there are linked equilibria. So if some extra CO2 dissolves, then the equilibrium of CO2 with HCO3- shifts to make more HCO3-, and there’s even a bit more CO3–. This is buffering, and the amount of dissolved CO2 stays at just over 1%.
In fact, the CO3– is in equilibrium with solid CaCO3, including shells, corals, etc, and that equilibrium can shift too, dissolving some CaCO3.
Re: anna v (13:09:22)
You’ve raised a lot of interesting points. I thank you, Dr. Spencer, Phil., and others (including those who have posted links to data) for causing me to take a far more careful look at CO2 than I have previously.
–
After taking a first exploratory look at some of the data, one important thing that seems to be escaping the (core) focus of the discussion is the substantial north-south asymmetry of Earth.
–
A comment I would offer to several who have posted:
Misrepresenting Dr. Spencer’s presentation is a questionable tactic. In particular, many have seriously misrepresented the meaning of the 90/10 split; the discussion barely even attempted to focus on what it really means. Also, many have failed in their interpretations to acknowledge the proportion of the variation explained by the demonstrative-model put forward to stimulate exploration, discussion, & learning.
I hope Phil. will take up Anthony’s offer. [Note: I found Phil.’s comments at Phil. (20:44:36) & Phil. (06:43:38) instrumental in this discussion.]
Anthony: Thank you for hosting this discussion. These discussions cause me to dig deeper – & in areas that might not regularly cross my mind.
– – –
Re: Leif Svalgaard (08:41:22)
I appreciate your concerns, but for balance I will comment on the downside:
That would leave the system wide-open to abuse by administrative-types who substitute overtime-hours for true talent. I have had more than my share of dealings with such folks who have unyieldingly-discordant domination instincts – and I know they would seize such an easy opportunity to deliberately engineer crippling inefficiency into the system — they simply cannot help themselves – and since their tactics can undermine the sustainable defense of civilization, critical stalemating effort needs to be invested in the maintenance of balance.
Perhaps there is a middle-ground approach that does not necessarily become yet another opportunity for “adminabalism” (administration+ballistic+cannibalism). We are naive if we let our guard down, thinking the science establishment is immune to:
1) ideologically-driven system-self-destruct political appointees & affiliates (on a mission to tear down institutions organized around values perceived as a political threat).
2) other (perhaps less-malicious) entities intent on governing which tools (such as low-confidence computer models) are employed to manage culture.
Most honest researchers I know are already nearly-overwhelmed, as stringent administrative controls creep deeper & deeper into the research arena. I would argue that the efficient-research solution is more liberation, not more control. Bright folks will have more time to cover more ground, spot research deficiencies, and innovate if they spend less time tied up with infighting & formal administrative processes that suck time, resources, & mental freshness.
I understand, appreciate, & respect the concern you have expressed; I add this comment with balance in mind.
– – –
bill (14:46:30) “I take it that you have done this and could share you results and conclusions?”
Based on the pattern in your comments, you really need to do these calculations for yourself. If you don’t have 10 minutes to do them in Excel, you can use the webpage mentioned upthread by others to gain insight in mere seconds:
http://www.woodfortrees.org/plot/esrl-co2/isolate:2/mean:1/scale:1/from:1990/to:2000
Adjust the “mean (samples)” “Value” upwards in increments of 1 (month) and notice what happens as you roll through multiples of 12 (i.e. 12, 24, 36, …). This should help you discern the manner in which samples integrated to annual (& subharmonic) resolution obscure seasonal signals.
A little more:
If you take the time to look at the Antarctica (“South Pole”) series [perhaps you have already done this, but perhaps without exploring time-integration], you will notice a 6 month phase shift. If you additionally look at the other sites, you will notice striking geographic variation in both amplitude & seasonal pattern.
Final (more general) note:
Beware the hazards of drawing conclusions without investigating the sensitivity of parameter estimates to scale & localization in the presence of spatiotemporal heterogeneity.
bill (15:45:22) :
Ice core data gives about 40 year temp resolution and as said above 150 year CO2 at 12000 years ago.
I don’t know about temps, but the time resolution for 10Be [and for the annual rings] is one year…
Leif, I spit Coors Light on my puter screen!!!! Your statement is either (or both) the understatement of the year, or the overstatement of the year! It reminds me of the question, “Who is buried in Grant’s tomb?”
Re: Nick Stokes (16:26:17)
Thank you for these comments (on linked chemical equilibria), which make the picture a whole lot more interesting.
Could you (or anyone else) comment on the role of wind variations (& related surface roughness) in hemispheric, regional, local, & microspatial variations in these equilibria? – and perhaps also comment on how this varies across temperature gradients?
Maybe someone knows of a link to a really good primer?
Paul Vaughan (17:29:55) :
I appreciate your concerns, but for balance I will comment on the downside:
No balance is needed, nor wanted. If the review process is public and transparent, the system cannot be abused.
Leif Svalgaard (18:12:43)
“If the review process is public and transparent, the system cannot be abused.”
The “abuse” will come in the tedious time-consumption – i.e. scientists getting caught hostage by the process. Since each scientist’s time is finite, this will bite into time for innovation.
However, clusters of bright minds will naturally engineer means of balancing cumbersome administrative duties (“red tape”) with research objectives.
Leif Svalgaard (18:12:43) “No balance is needed, nor wanted.”
Paul Vaughan (19:03:44) :
“If the review process is public and transparent, the system cannot be abused.”
The “abuse” will come in the tedious time-consumption – i.e. scientists getting caught hostage by the process.
Not at all. I regularly review papers by other scientists. An example is my review of Dikpati’s prediction of a very large cycle 24: http://www.leif.org/research/Dikpati%20Referee%20Report.pdf
Not tedious, but necessary, and at times rewarding because the review forces one to focus on the idea [and even learn a bit].
Joel Shore (12:02:13)
Depending upon what you look at, the earth has never been more than 5-10 deg C warmer than it is now in the past 6 X 10^8 years. In the past 450K years it hasn’t been over 2-3 degrees above present. We have had 5000 ppm of CO2 and the temperature has never run away. We have only one source of heat, the sun. Our climate system varies by retaining more or less of that heat by whatever mechanism, and we certainly have very few facts about how it does that. What we don’t know about climate is far more than we do. I have been looking at this for 48 years, and without some new measured, real-world correlated facts you aren’t going to convince me otherwise.
Paul Vaughan (and George Smith)
Here is a good set of notes on dissolved carbonate chemistry. The last page (sec 6.2) is quite relevant here.
@E.M. Smith
“We’ve reach “Peak Fish” some decade or two ago. (As of now some 30% of all fish eaten is aquacultured so nobody cared much about the Peak Fish crisis…) The fastest we can harvest them from the ocean. Do you think that maybe hauling billions of pound of fish out of the ocean might reduce the quantity of carbonate pellets the fish in the ocean can excrete?
Do you think that might leave more CO2 in the ocean to outgas?”
Do you think the “dead zones” we have occasionally noticed off the coasts of continents might be symptoms of this?
Realism:
Steve Keohane (20:33:40) “What we don’t know about climate is far more than we do.”
Very refreshing to see non-partisan honesty.
George E Smith,
I’m not formally an expert but here’s my understanding to help your questions FWIW
(1) the balance of CO2, HCO3-, and CO3– is a whole equilibrium chain; changing one affects all; the net balance is that CO2 partitions between water and air at 15ºC approximately 50:1 by Henry’s Law; this proportion changes a tiny bit as the solubility decreases with increasing temp; but with the size of the oceans, a tiny change of temperature magnifies into a huge outgassing.
(2) the NH seasonal “wild swing” of CO2 is the effect of the temperate forests: Canada and the Russian taiga. In winter there is net exhaling of CO2 from rotting-down processes.
My chief sources here for understanding CO2 are:
Glassman http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html
Floor Anthoni http://www.seafriends.org.nz/issues/global/acid2.htm#carbon_situation (he explained why ocean acidification is more alarmist nonsense – because of the ever-present Ca++ ions, ready to make shells)
Segalstad http://www.greenworldtrust.org.uk/Science/Scientific/Segalstad.htm
and I’ve done my own page of notes on CO2 http://www.greenworldtrust.org.uk/Science/Scientific/CO2-flux.htm
Hope this helps
Gerald Machnee:
“if CO2 is the main factor in temperature increase, then the global temperature must increase EVERY year”
Not true at all. Why would CO2 stop weather?
“Check the latest studies – The 13C is not only from fossil fuels”
Link to those ‘latest studies’ please.
George E. Smith:
“And yes I do believe that CO2 molecules can and do absorb long wave infra red radiation; that does not equate to raising the global temperature.”
That is a horrible self-contradiction. Whatever absorbs more radiation, gets warmer. There is more CO2, hence more absorption, hence…
anna v:
“The isotope card has been burned since it was noted that part of the algae/ plankton prefer the C13 way. There is lots and lots of them in the oceans.”
Do you believe that the algae and the plankton suddenly started going mental about 200 years ago, after hundreds of thousands of years of not doing very much? Why would they have done that?
Sorry I have not been able to respond…I was in Stockholm yesterday and Helsinki today. I quickly scanned the various comments that have been made, and would like to clarify….
The two coefficients in the simple model I used have different units…in fact, the anthropogenic one is unitless (just a fraction). I think someone pointed out that since the observed atmospheric rise is 50% of the anthropogenic emissions, then my “10% anthropogenic” fit is really 20%, which is true…I thought of this shortly after posting but was too busy traveling to do anything about it. Similarly, the “20% anthropogenic” fit is then really 40% anthropogenic.
In case anyone missed it, the main point of the post was not to advance a new and complete explanation of the connections between CO2 and temperature. It was to show there is very clear evidence that temperature — either directly or indirectly (through biological activity) does impact the atmospheric concentration of CO2…at least on interannual time scales. Now, since El Nino has been more prevalent in the last 30 years, isn’t it possible that *some* of the warming and CO2 increase during that time is natural?
It is a perfectly legitimate scientific hypothesis, and the fact that it is avoided like the plague illustrates how political climate science has become.
-Roy
Do you believe that the algae and the plankton suddenly started going mental about 200 years ago, after hundreds of thousands of years of not doing very much? Why would they have done that?
Please give a link for the hundreds of thousands of years of not doing very much.
200 years ago the temperatures started rising because of getting out of the little ice age, and the flora responded accordingly. One can imagine many reasons why a C13 rich strain might flower better with heat.
The argument about fossil fuel origin of C13 can hold only if there are no other sources of C13 in the game.
Roy W. Spencer (04:57:10) :
… It was to show there is very clear evidence that temperature — either directly or indirectly (through biological activity) does impact the atmospheric concentration of CO2…at least on interannual time scales.
But then doesn’t this lead on to my points that if temperature is pushing CO2 AND it is doing it with a 6 month lag it SHOULD appear in the ice core records as effectively zero lag between CO2 and Temperature. An 800(approx) lag is usually quoted?
Whilst biologic conditions during the iceage will be different (although still active in warmer latitudes) the entry into the icae age from temperatures (and presumably similar vegitation) that is similar to today should show only a 6 month lag:
entry into iceage CO2 falls 4000 years after temp starts to drop
http://img12.imageshack.us/img12/9952/iceage100200kbq5.jpg
exit from ice age (last) shows nearly simulateous co2 and temperature (which is pushing which?)
http://img11.imageshack.us/img11/6826/iceage040kkq1.jpg
Dr Spencer, ( or anybody else who has access to the data)
It would be really interesting if you could make the same plots of CO2 changes and temperature anomalies from the data of the antarctic only. i.e. antarctic temperature anomalies versus CO2 yearly changes.
It is interesting that with such a simple model a first order “explanation” can be found.
Gerald Machnee says:
It means exactly what it says: For a function like y = A + log(x), each doubling of x produces the same amount of change in y. So, going from 280ppm to 560ppm produced the same amount of change in y as going from 140ppm to 280ppm. This is in contrast to a linear function where the same amount of change in x produces the same amount of change in y…In particular, going from 280ppm to 560ppm would produce the same amount of change in y as going from 0ppm to 280ppm.
I don’t think what I said is in contradiction to what Archibald shows although I haven’t tried to look in detail at the quantitative values that he shows.
RW says:
Indeed…and a simple way to see this is to consider the seasonal cycle in a place such as here in Rochester. I think everyone would agree that it is a very significant feature of the climate here…and yet as we go from winter to summer, we do not see a steady temperature increase each day. I haven’t looked at the actual data but my guess would be, for example, that week-long periods in the spring with negative temperature trends are not at all uncommon.