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:
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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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Roy,
In your model equation, what values were used for the variable “Anthro”?
What would happen if the Anthro component were simply omitted? Can a value be found for the “a” coefficient that results in the model fitting the observations even better?
It’s not the fact that warmists have an opposite opinion that pisses me off.
It’s the lack of sound arguments and open discussion, the manipulation, the lying, the cherry picking, the arrogance, the style and the political agenda that makes me mad.
This kind of articles shuts them up all right.
Eager to read the comment by Ferdinand Engelbeen
Our nice friend George said:
“Let’s face it; there aren’t a whole lot of zoogremlins swimming around in your favorite Champagne, but if you warm it up, it will outgas more CO2.”
Let’s also face that if you allow your champagne to warm you clearly cannot be trusted with champagne.
I like to mention the Nevada FACE facility where they measure background CO2 continuously in a desert environment and which for 10 years has shown little or no trend (though a lot of scatter). Nobody ever comments about it but I see it as important evidence. Presumably these scientists are doing the background measurements correctly otherwise the whole experiment would be pretty pointless.
http://www.unlv.edu/Climate_Change_Research/NDFF/co2_treatment.htm
I’ve been wondering why Kealing never chose a desert environment; a short drive from his office, after having already reported in his talks that he got low background readings in such environments. I mean why a volcano in the Pacific? What on earth was he thinking about? Even today on the ML website they say it’s the cleanest air in the world which is nonsense: It’s a volcano for Pete’s sake – and they admit they need to correct for it’s emissions! However that’s a side issue. It just makes me wonder about Kealing’s decision-making mechanism. But maybe he was a surfer.
No doubt Engelbeen will pop in and link his website and mention that the Antarctic station agrees with ML.
Interesting feature of Spencer’s analysis is that it implies Segalstad/JAworowski kind of criticism of IPCC interpretation of ice core records. If XX century rise in CO2 concentration up to 380 ppmv was mainly natural process than it is highly unlikely that highest concentration in previous 650 000 years could be only 280/290 ppmv, as “consensus science” assume. The most basic IPCC cornerstone simply must be wrong (as Segalstad and Jaworowski conjecture).
Well, some more simple arithmetic. We burn nearly 10 Gigatons of C per year. The atmospheric increase is about 5-6 Gt. The rest is thought to go into the ocean.
But if the ocean is a nett source of CO2 to the air, then where does it all go?
The April CO2 SPPI report is available: http://scienceandpublicpolicy.org/images/stories/papers/originals/april_09_co2_report.pdf
Rob (13:18:07) :
Since the middle of the last century, the Sun is in a phase of unusually high activity
There is good evidence that this is not the case. A starting point for you might be this: http://www.leif.org/research/Napa%20Solar%20Cycle%2024.pdf before we go to the next [more technical] level.
As Al Gore would say…. “Did they ever fit together?”
To Nick Stokes, re “Where does it all go”
The earth is obviously greening:
http://earthobservatory.nasa.gov/Features/GlobalGarden/
Now where do you suppose trees gets their carbon from? Maybe you can use some simple arithmetic.
If Dr Spencer is right then we should see a sharp fall in the rate of CO2 increase in the next year.
If you look at the annual mean growth rate of CO2 at Manu Loa (link below) then there does seem to be decrease over the last 3 or 4 years. Although year to year variability is high and is increasing.
BTW, the year to variability can’t be explained by the anthropogenic CO2 theory and is serious problem for it.
http://www.esrl.noaa.gov/gmd/ccgg/trends/
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.
Well, here’s what I don’t understand. After 90 thousand years of cold temperatures, when the CO2 levels are at their lowest, the temperatures start rising, and continue to rise for that eight century interval before the CO2 levels begin to go up. Similarly, after ten thousand years of interglacial, when the CO2 is at its highest, the temperatures start dropping, and continue to do so for eight centuries before the CO2 levels follow.
How is it that CO2 levels that have been stable for thousands of years cause 800 years of temperature changes in the first place?
JamesG
More simple arithmetic – the plant biomass is about 500 Gt carbon. This Spencer theory would imply an increase of about 10 Gt/year, about 2%. If that has been going on for a while, we’d notice. To put it another way, we’ve burnt in total over 300 Gt. That would be a 60% increase.
Your link says about 6% increase in productivity over 25 years (which isn’t quite the same).
“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.”
These things are not ‘assumed’.
“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?”
Why, of course. But we know that this portion is very small. How we know this should be common knowledge among anyone interested in climate science, but let’s run through it one more time:
Observation 1: concentration of atmospheric CO2 is rising steeply. It is 40% higher than it was at any point in the 800,000 years or so before 1800.
Observation 2: not only is the concentration rising steeply, but its isotopic composition is changing. After 800,000 years or so of little variation, the proportion of CO2 molecules containing a 13C atom began dropping sharply about 200 years ago.
Observation 3: In the oceans, a similar drop in 13C is observed, and the quantity of CO2 in the oceans is found to be rising.
Conclusion: the oceans cannot be the source of the extra CO2, because if they were, then a) the amount of CO2 in them would be falling, not rising; and b) the δ13C in the oceans would have to be rising, not falling. Roy’s ideas fail to explain the observations, and must therefore be discarded.
Instead, we can see that obviously, the extra CO2 must be coming from a reservoir with a lower δ13C than both atmosphere and oceans. Who might know what that could be?
If, despite the isotopic evidence, you want to believe that warming has caused the rise in CO2, then you can see from ice cores that the relation between CO2 and temperature that held for 800,000 years or so was that a 1°C rise in temperature corresponded to about an 8ppm rise in CO2. Therefore, to explain the ~110ppm rise in CO2 since 1800, we require a temperature rise of 14°C. Hands up if you believe it’s got 14°C warmer globally since 1800.
“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… it would mean that the ocean became a net source of more atmospheric CO2 around 1930.”
The oceans are a net sink of CO2. Therefore, the model fails.
“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.”
How outrageously unscientific, to pre-emptively claim that all possible objections must be political. Strenuous and vehement objections are the only sensible scientific response to a deeply flawed analysis. Politics is irrelevant.
JamesG
In his autobiography Keeling says he took the job there because it was more fun and would be outdoors (he was a keen outdoors man) and better than the alternative offered-a job in an office based environment . Nothing more scientific than that, as he had no experience whatsoever of co2 analysis before taking up the job.
tonyb
It’s interesting. I was looking for a way to comment on Dr. Spencer’s blog but there was no link. I had a few questions for him, one related to data source and the other was why didn’t he do a multivariate regression to find the ratio between natural and AGW rather than hand match the temps.
Either way, it’s an interesting analysis and if we trust the long term temperatures it might be worthwhile to do the regression.
Or maybe CO2 and temperature are so loosely connected that the relationship won’t show for hundreds of years. How did CO2 and temperature get so closely coupled — Just because Al Gore says?
Joel
Your question may have been answered.
1) First the carbon dioxide needs to get into the ocean.
2) Second, the ocean needs to be cool enough to retain it for long enough to allow photosynthetic plankton to assimilate it.
3) Then the rest of the plankton food chain needs to really incorporate the carbon products into the biomass.
1) is not often considered thoroughly – there is not sufficient ocean surface area for effective diffusion of carbon dioxide from the atmosphere into the ocean to support the bulk of photosynthetic life there. The key source is precipitated rain water, saturated with carbon dioxide, mainly in temperate and subpolar zones. In tropical zones, both on land and in the ocean, the respiration of the biomass accounts for much of the circulating carbon.
2) Tropical oceans, and tropical landmasses recycle much of the carbon dioxide reaching the surface dissolved in rain directly back into the atmosphere. Subtropical desert regions consolidate carbon dioxide into carbonate minerals which fix sand dunes and mineral-rich lake deposits.
3) Biomass has two parts – the organic and the inorganic. The organic bit -protein, carbohydrate, lipid etc., and the inorganic stuff – shells, bones, dental stuff, maybe I can include resin and some resistant plant products here too, stuff that is not easily biodegradable. The organic stuff is readily recycled, but the inorganic stuff is either fossilized, or incorporated into sediments. Some scientists think that even the inorganic stuff is recycled into petroleum products, as long as there is a source of carbon and hydrogen, and the temperature and pressure are high enough.
Nicely done.
I, too, would suspect that you need a 95-5 run with an offset to flatten the curve. Potentially, there is also an algae bloom vs sunlight cloud modulation distractor…
FWIW I got sent down the C12 / C13 isotope ratio rat hole too. The Result:
http://chiefio.wordpress.com/2009/02/25/the-trouble-with-c12-c13-ratios/
Enjoy.
BTW, one of the simplest things wrong with the C12/13 ratio is that each fossil fuel has a unique ratio and it varies by deposit of “stuff”; so unless you know where all the past oil, coal, and gas came from and what it’s ratio was then, you must “guess”.
Another? How much CO2 comes from mid ocean ridges? Is it all the same ratio? How much from methane seepage from clathrates? With what ratio? What is the impact of ocean floor deposits and plate subduction on the CO2 ratios produced in the volcanos above those plates? With what time lag? Was the CO2 ratio different in the past when there was different “stuff” on the ocean floor? By how much? What’s down there now? How much oil, coal, gas is consumed by bacteria each year everywhere on the planet? With what ratios? …
You get the idea. What we don’t know swamps what we do. But that still doesn’t seem to stop folks from calculating fantasies to 2 decimal points…
Oh, and there are two major plant metabolisms (called C3 and C4 for the number of carbons in a key step). They consume C12 / C13 in different ratios. How much C4 metabolism biomass has existed on the planet at all times of interest for production of soil carbon (thus determining the ratio of releases from all soils…)? (Hint: Grasses are the major – but not only- C4 plant type. They are only about 6 million years old…)
It’s not a simple problem and the answer that “we know” is just hubris.
Flanagan (13:08:37) :
Well, there’s nothing new here. CO2 desorbing from oceans is one of the most classical positive feedbacks in global circulation models. End of the story.
Exactly, any positive feedback from additional CO2 seems to be over. Shouldn’t we already have had a temperature “runaway” without any additional anthropogenic CO2 whatsoever?
When I first started looking into AGW for myself I was trying to disprove a colleague who was a skeptic. But when I read articles or blogs that supported the AGW theory, especially of the alarmist variety, I realized something was not right as the arguments in favour were fuzzy, not very clear, more like an illusion one must accept as a matter of faith. You could not grab hold anything substantial that would give clarity to how man alone was causing this warming, which did not seem substantial or unusual from a historical perspective, and how the problem could spiral out of control- other than the models say so.
But articles like Spencers exist in abundance on the the other side of the debate, and they encourage debate. They make no claims to certainty and do not insist the science is settled, and their articles tend to lift the fog on this fuzzy science, and are not hidden behind subscription walls. The science as they present it is logical and makes sense and relatively free of assumptions that are not supported by evidence or a healthy understanding of the process (eg. Climate models seem to minimize solar forcing, clouds and precipitation efficiency effects on climate due to a low level of understanding and lack of accurate historical data or observations).
Unfortunately, the alarmists will always denounce any articles that rock their world as being funded by Big Oil scientists, like Spencer is accused of, and fail to acknowledge there is a profit motive and political motive on their side. And since the debate is closed, this article like many others will simply be ignored.
Then there is peer review. Articles tend to not get published which challenge the establishments consensus. Peer review is a form of censorship. Einstein never had his great theories subject to peer review until he went up against Bohr and challenged the Quantum Theory as being incomplete. This theory had achieved consensus status in Copenhagen in 1927 and the science was said to be settled.
His first paper was rejected in 1935, Einstein had never heard about peer review before this and was furious the paper had been to others without his permission or knowledge who they were. In the past peer review took place after publishing, although before publishing scientists would send their drafts to other scientists they respected for comments. He then sent it in to a journal which did not do peer review and got published.
I have also discovered this corrosive influence is not limited to Climate Science but is pervasive in all science and even social sciences, including economics and history. Thats OT, so thats all I will say about that.
Monster,
The primary driver of climate change is the interaction of the earth’s orbital parameters: eccentricity, tilt, and wobble which were proposed by Milankovich more than a century ago and verified in the 1970-80s by the CLIMAP and SPECMAP projects. These cycles produce the large-scale glacial-interglacial oscillations. What happens on the shorter terms (millennial, century, and decade) can be attributed to other causes.
JamesG (15:31:32) : I’ve been wondering why Kealing never chose a desert environment; a short drive from his office, after having already reported in his talks that he got low background readings in such environments. I mean why a volcano in the Pacific? What on earth was he thinking about? […] It just makes me wonder about Kealing’s decision-making mechanism.
Let me think… I can put a CO2 station where I will spend years of my life in the boring stinking empty hot desert, or on the side of the mountain in a tropical paradise with fabulous vacation accommodations, floor shows, fantastic rum drinks, lush tropical forests to die for, and views that can’t be beat from the best beaches in the world.
Decisions decisions… (I don’t think it’s his “decision-making mechanism” that has issues 😉
Me? I’d have chosen South Island New Zealand … Then again, I like both beaches AND skiing… and roast leg of lamb, with those wonderful light red wines the Kiwis make … but the mind wanders… Oh, and the air would be really really clean and well mixed there, yeah, that’s it, well mixed.
I have recently seen dire predictions about higher atmospheric CO2 acidifying the oceans and disrupting the ability of shellfish to deposit calcium carbonate in their shells efficiently. No doubt this is the beginning of the fall-back position when temperature changes have obviously failed to follow CO2 levels.
RW, your points may be valid (or not) but I am struck by the way you so confidently assume that the whole business comes down to the variability of CO2. First, your line of argument completely fails to deal with the established facts that the world has been both much warmer and much colder than it is now, before the emergence of humans and after. Since everything that we’re observing now is clearly within the bounds of natural variability, why is it necessary to invoke human causation? In fact, why is it not specious to do so before carefully eliminating all possible natural causes?
Second, I know from my own line of work that when you try to explain the behavior of highly complex systems in terms of a single variable you’re going to be wrong. It’s called “excessive reductionism”, and it’s an unhealthy phenomenon, especially when you don’t really know what all the other variables are.