NOTE: Earlier today I posted a paper from Joe D’Aleo on how he has found strong correlations between the oceans multidecadal oscillations, PDO and AMO, and surface temperature, followed by finding no strong correlation between CO2 and surface temperatures. See that article here:
Warming Trend: PDO And Solar Correlate Better Than CO2
Now within hours of that, Roy Spencer of the National Space Science and Technology Center at University of Alabama, Huntsville, sends me and others this paper where he postulates that the ocean may be the main driver of CO2.
In the flurry of emails that followed, Joe D’Aleo provided this graph of CO2 variations correlated by El Nino/La Nina /Volcanic event years which is relevant to the discussion. Additionally for my laymen readers, a graph of CO2 solubility in water versus temperature is also relevant and both are shown below:
Click for full size images
Additionally, I’d like to point out that former California State Climatologist Jim Goodridge posted a short essay on this blog, Atmospheric Carbon Dioxide Variation, that postulated something similar.
UPDATE: This from Roy on Monday 1/28/08 see new post on C12 to C13 ratio here
I want to (1) clarify the major point of my post, and (2) report some new (C13/C12 isotope) results:
1. The interannual relationship between SST and dCO2/dt is more than enough to explain the long term increase in CO2 since 1958. I’m not claiming that ALL of the Mauna Loa increase is all natural…some of it HAS to be anthropogenic…. but this evidence suggests that SST-related effects could be a big part of the CO2 increase.
2. NEW RESULTS: I’ve been analyzing the C13/C12 ratio data from Mauna Loa. Just as others have found, the decrease in that ratio with time (over the 1990-2005 period anyway) is almost exactly what is expected from the depleted C13 source of fossil fuels. But guess what? If you detrend the data, then the annual cycle and interannual variability shows the EXACT SAME SIGNATURE. So, how can decreasing C13/C12 ratio be the signal of HUMAN emissions, when the NATURAL emissions have the same signal???
-Roy
Here is Roy Spencer’s essay, without any editing or commentary:
Atmospheric CO2 Increases:
Could the Ocean, Rather Than Mankind, Be the Reason?
by
Roy W. Spencer
1/25/2008
This is probably the most provocative hypothesis I have ever (and will ever) advance: The long-term increases in carbon dioxide concentration that have been observed at Mauna Loa since 1958 could be driven more than by the ocean than by mankind’s burning of fossil fuels.
Most, if not all, experts in the global carbon cycle will at this point think I am totally off my rocker. Not being an expert in the global carbon cycle, I am admittedly sticking my neck out here. But, at a minimum, the results I will show make for a fascinating story – even if my hypothesis is wrong. While the evidence I will show is admittedly empirical, I believe that a physically based case can be made to support it.
But first, some acknowledgements. Even though I have been playing with the CO2 and global temperature data for about a year, it was the persistent queries from a Canadian engineer, Allan MacRae, who made me recently revisit this issue in more detail. Also, the writings of Tom V. Segalstad, a Norwegian geochemist, were also a source of information and ideas about the carbon cycle.
First, let’s start with what everyone knows: that atmospheric carbon dioxide concentrations, and global-averaged surface temperature, have risen since the Mauna Loa CO2 record began. These are illustrated in the next two figures.
Both are on the increase, an empirical observation that is qualitatively consistent with the “consensus” view that increasing anthropogenic CO2 emissions are causing the warming. Note also that they both have a “bend” in them that looks similar, which might also lead one to speculate that there is a physical connection between them.
Now, let’s ask: “What is the empirical evidence that CO2 is driving surface temperature, and not the other way around?” If we ask that question, then we are no longer trying to explain the change in temperature with time (a heat budget issue), but instead we are dealing with what is causing the change in CO2 concentration with time (a carbon budget issue). The distinction is important. In mathematical terms, we need to analyze the sources and sinks contributing to dCO2/dt, not dT/dt.
So, let us look at the yearly CO2 input into the atmosphere based upon the Mauna Loa record, that is, the change in CO2 concentration with time (Fig. 3).
Here I have expressed the Mauna Loa CO2 concentration changes in million metric tons of carbon (mmtC) per year so that they can be compared to the human emissions, also shown in the graph.
Now, compare the surface temperature variations in Fig. 2 with the Mauna Loa-derived carbon emissions in Fig. 3. They look pretty similar, don’t they? In fact, the CO2 changes look a lot more like the temperature changes than the human emissions do. The large interannual fluctuations in Mauna Loa-derived CO2 “emissions” roughly coincide with El Nino and La Nina events, which are also periods of globally-averaged warmth and coolness, respectively. I’ll address the lag between them soon.
Of some additional interest is the 1992 event. In that case, cooling from Mt. Pinatubo has caused the surface cooling, and it coincides in a dip in the CO2 change rate at Mauna Loa.
These results beg the question: are surface temperature variations a surrogate for changes in CO2 sources and/or sinks?
First, let’s look at the strength of the trends in temperature and CO2-inferred “emissions”. If we compare the slopes of the regression lines in Figs. 2 and 3, we get an increase of about 4300 mmt of carbon at Mauna Loa for every degree C. of surface warming. Please remember that ratio (4,300 mmtC/deg. C), because we are now going to look at the same relationship for the interannual variability seen in Figs. 2 and 3.
In Fig. 4 I have detrended the time series in Figs. 2 and 3, and plotted the residuals against each other. We see that the interannual temperature-versus-Mauna Loa-inferred emissions relationship has a regression slope of about 5,100 mmtC/deg. C.
There is little evidence of any time lag between the two time series, give or take a couple of months.
So, what does this all show? A comparison of the two slope relationships (5100 mmtC/yr for interannual variability, versus 4,700 mmtC/yr for the trends) shows, at least empirically, that whatever mechanism is causing El Nino and La Nina to modulate CO2 concentrations in the atmosphere is more than strong enough to explain the long-term increase in CO2 concentration at Mauna Loa. So, at least based upon this empirical evidence, invoking mankind’s CO2 emissions is not even necessary. (I will address how this might happen physically, below).
In fact, if we look at several different temperature averaging areas (global, N. H. land, N.H. ocean, N.H. land + ocean, and S.H. ocean), the highest correlation occurs for the Southern Hemisphere ocean , and with a larger regression slope of 7,100 mmtC/deg. C. This suggests that the oceans, rather than land, could be the main driver of the interannual fluctuations in CO2 emissions that are being picked up at Mauna Loa — especially the Southern Ocean.
Now, here’s where I’m really going to stick my neck out — into the mysterious discipline of the global carbon cycle. My postulated physical explanation will involve both fast and slow processes of exchange of CO2 between the atmosphere and the surface.
The evidence for rapid exchange of CO2 between the ocean and atmosphere comes from the fact that current carbon cycle flux estimates show that the annual CO2 exchange between surface and atmosphere amounts to 20% to 30% of the total amount in the atmosphere. This means that most of the carbon in the atmosphere is recycled through the surface every five years or so. From Segalstad’s writings, the rate of exchange could even be faster than this. For instance, how do we know what the turbulent fluxes in and out of the wind-driven ocean are? How would one measure such a thing locally, let alone globally?
Now, this globally averaged situation is made up of some regions emitting more CO2 than they absorb, and some regions absorbing more than they emit. What if there is a region where there has been a long-term change in the net carbon flux that is at least as big as the human source?
After all, the human source represents only 3% (or less) the size of the natural fluxes in and out of the surface. This means that we would need to know the natural upward and downward fluxes to much better than 3% to say that humans are responsible for the current upward trend in atmospheric CO2. Are measurements of the global carbon fluxes much better than 3% in accuracy?? I doubt it.
So, one possibility would be a long-term change in the El Nino / La Nina cycle, which would include fluctuations in the ocean upwelling areas off the west coasts of the continents. Since these areas represent semi-direct connections to deep-ocean carbon storage, this could be one possible source of the extra carbon (or, maybe I should say a decreasing sink for atmospheric carbon?).
Let’s say the oceans are producing an extra 1 unit of CO2, mankind is producing 1 unit, and nature is absorbing an extra 1.5 units. Then we get the situation we have today, with CO2 rising at about 50% the rate of human emissions.
If nothing else, Fig. 3 illustrates how large the natural interannual changes in CO2 are compared to the human emissions. In Fig. 5 we see that the yearly-average CO2 increase at Mauna Loa ends up being anywhere from 0% of the human source, to 130%.
It seems to me that this is proof that natural net flux imbalances are at least as big as the human source.
Could the long-term increase in El Nino conditions observed in recent decades (and whatever change in the carbon budget of the ocean that entails) be more responsible for increasing CO2 concentrations than mankind? At this point, I think that question is a valid one.
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Steve hemphill,
Of course, there is diffusion above closing depth, although less and less, as the firn densifies. For the Law Dome ice cores, that is at 72 m depth, where the ice is closing, but still has open bubbles. Even above the closing depth, there is diffusion, but still a top-down gradient, which means that closing is faster than diffusion. As both firn CO2 and ice CO2 shows the same value, no differences caused by drilling methods, ice handling, ice/air diffusion, fractionation, etc. are showing up.
At closing depth, the difference in ice-gas age is about 40 years and the average gas age is ten years younger at the same depth with a spread of 8 years, that is the time needed to close all bubbles.
This is for the Law Dome ice core. I didn’t find direct figures for the Vostok ice core on the net (but remembered some +/- 600 years resolution).
There is a lot more coral decay/death than growth worldwide including the Great Barrier Reef.
http://www.msnbc.msn.com/id/4351294/
In any case, I want to (1) clarify the major point of my post, and (2) report some new (C13/C12 isotope) results:
1. The interannual relationship between SST and dCO2/dt is more than enough to explain the long term increase in CO2 since 1958. I’m not claiming that ALL of the Mauna Loa increase is all natural…some of it HAS to be anthropogenic…. but this evidence suggests that SST-related effects could be a big part of the CO2 increase.
2. NEW RESULTS: I’ve been analyzing the C13/C12 ratio data from Mauna Loa. Just as others have found, the decrease in that ratio with time (over the 1990-2005 period anyway) is almost exactly what is expected from the depleted C13 source of fossil fuels. But guess what? If you detrend the data, then the annual cycle and interannual variability shows the EXACT SAME SIGNATURE. So, how can decreasing C13/C12 ratio be the signal of HUMAN emissions, when the NATURAL emissions have the same signal???
-Roy
Roy, I have a gut feeling that a part of that R-squared on figure 4 could be a spurious result of the detrending. As you point out, Figures 1 and 2 share the same “bend” so what you are seeing on Figure 4 is in some part a consequence of both sets of detrended data sharing a tendency to positive anomalies early and late on in the time series and a negative anomaly in the middle.
Worth a check, based on a quadratic fit even if the square term may be bordering on insignificant.
Of all the people who follow this blog and comment regularly, I probably have the least amount of scientific and mathematical background. Nevertheless, the topic is of great interest and fascination to me so I have to base my beliefs, to a large extent, on logic, historical observation, accuracy of measured data and analysis of the obvious or perceived motivations of those on both sides of the debate. IMHO, one cannot look at the issue from those four perspectives and arrive at any position other than that of skepticism.
I tried to follow the comments on this thread over the last 72 hours until my head hurt. Finally, the comment by Norm K earlier today put things in a layman’s that I could follow. Thanks, Norm.
Eli, a link to the MSM? Seriously? Come-ON! That’s pathetic.
Hello,
Err, is this the same idea as,
http://www.rocketscientistsjournal.com/2006/10/co2_acquittal.html
The Acquittal of CO2 – Jeffrey A. Glassman PhD.
Realclimate.org and Gavin Schmidt have been “discussing” the idea, and Dr. Glassman has answered many of the questions raised…
http://www.rocketscientistsjournal.com/2006/11/gavin_schmidt_on_the_acquittal.html
Most “rebuttals” seem to revolve around the idea that the oceans can not or will not absorb much more CO2.
Motl Lobos discusses this on this thread.
http://motls.blogspot.com/2007/11/ocean-carbon-sink-henrys-law.html
Even I have managed a Layman’s simplified overview…
http://www.globalwarmingskeptics.info/modules.php?name=Forums&file=viewtopic&t=94
Whereever the idea came from, it is good to see it being more widely discussed.
Personnally, I believe it maybe THE one that puts the long awaited realistic view of CO2, and the natural processes effecting it climate science so desperately needs at present.
It does explain the 800 to 1,000 year lag between temperature change AND THEN CO2 level changes better than just about any other idea I’ve seen.
Hello again,
May I also add that thinking about the world’s oceans as I try to describe on this thread, may help, (as if peeled off a tangerine…)
http://www.globalwarmingskeptics.info/modules.php?name=Forums&file=viewtopic&t=232
After some consideration it may become apparent that the Vostock and Mauna Loa CO2 (processed) data appears to be a bit too similar (the raw data is effectively “unavaliable” at present), seeing as one is in a large natural CO2 sink (Vostock) and the other is in one of the world’s largest natural degassing areas, the Western Pacific (Mauna Loa).
Natural variation, that is really a big problem for THE climate science at present.
Norm K,
The problem is that atmospheric increases don’t react on the differential of the emissions (here expressed in Mt CO2, not MtC), but on absolute levels (in fact mainly the difference air-ocean pCO2). You compare emission increase rates with atmospheric CO2 level increases, but you should compare emission increases with CO2 increases…
The emissions totalised 80 GtC 1990-2002 and 22 GtC 2003-2005 (I have no figure yet for 2006).
The emissions, if these would accumulate in total in the atmosphere should give an increase of 2.93 ppmv/yr (1990-2002) and 3.51 ppmv/yr (2003-2005). That is +20%.
The increase in atmospheric CO2 over the same periods changed +22%.
Not bad for a process where the trend is mostly controlled by the emissions (a small variation due to temperature changes allowed…).
Dear Dr. Spencer,
The dCO2/dt relationsship you found is 4,300 mmtC/deg. C, which is 4.3 GtC/°C or about 2.1 ppmv/°C. I did find similar values: 2-4 ppmv/°C for El Niño, La Niña and Pinatubo temperature fluctuations. And 2.6 ppmv/°C for the global seasonal variations vs. global temperatures (land+oceans).
Thus we do agree about the influence of temperature fluctuations on CO2 rate of increase.
Where we disagree, is that you see the temperature as a one-way driver. It goes both ways: the temperature drop of the Pinatubo and the El Niña episodes show similar drops of CO2 rate of increase as the El Niño episodes the other way out.
If we may assume that the rate of increase vs. temperature currently observed is similar for longer-term influences (over decades) on absolute CO2 levels, then the observed 1959-2004 temperature increase of about 0.6°C has added about 1.3 ppmv of the 60 ppmv measured in the same period.
If we go the other way out, that the change in temperature was the sole driver of CO2 changes, then the temperature has added 60 ppmv for a change of 0.6°C, or 100 ppmv/°C, never seen in history…
I can’t place your remarks on 13C/12C ratios without figures and/or graphs…
“The increase in atmospheric CO2 over the same periods changed +22%.
Not bad for a process where the trend is mostly controlled by the emissions
(a small variation due to temperature changes allowed…).”
Oceans absorb and degass somewhere about 90 to 100 Gigatonnes annually, (IPCC figures)
so I’m not sure why you’ve added up 1990-2002, to get 80GtC, presumeably those are man’s emmissions.
They do sound more significant when added up 12 to 13 years at a time though..
I must admit to hearing quotes of CO2 has increased by 4% since 2002 (I think) ,
so that does not exactly tally with man’s emmissions either,
maybe a bit of exageration in the adding up (or the method used) to get to 22% perhaps…..
The hypothesis as I understand it is that a small change in temperature of the world’s oceans causes the Solubility pump to change the amount of CO2 “pumped”, this can (and does) easily dwarf man’s emissions.
Which seemingly they do. (Depending on how you add up, obviously.)
Derek,
The raw (hourly average from 4 measurements) CO2 data from Mauna Loa and other base stations (including the South Pole) are available at:
ftp://ftp.cmdl.noaa.gov/ccg/co2/in-situ/ The data are not pre-processed or deleted. Some bear flags, because of known (system or natural) disturbances of the measurements. These falgged data are not used for daily, monthly or yearly averages. But including or excluding the outliers doesn’t change the yearly average with more than a few tenth of a ppmv…
Ice core/firn data of Law Dome and South Pole atmospheric CO2 have a 20 years overlap and are similar for the same time period, within the +/- 1.2 ppmv accuracy of ice core measurements.
Several ice cores, measured by a lot of different teams show the same CO2 history.
10 base stations (see http://cdiac.ornl.gov/trends/co2/contents.htm ) and a lot more, measured by different teams and laboratories (continuous and via flask samples), measure the same trends, only influenced by the seasons, and a small altitude and N/S gradient.
That involves hundreds of people at tens of places and laboratories. I don’t think that all of them would cheat to keep their job, without anyone protesting against such a way of working…
Dear Stevo,
Sorry for the late reply… There are so many reactions that we needed more time (after all we still have a life besides these discussions…).
A few answers were already given in other responses:
– d13C/d14C levels don’t prove that humans are the sole cause of the increase in the atmosphere, but they prove that the deep oceans are not the cause of the increase…
– I did use your Segalstad example to show the difference between accumulation in % (the red dye) and the accumulation is mass (the extra inflow), all other variables being constant in total result.
Further:
– The solubility of oxygen in water is quite limited. Most of the O2 from vegetation photosynthesis is building up in the atmosphere. The other big oxygen user is vegetation decay. If decay and photosynthesis are in equilibrium (after a full seasonal cycle of one year), then no oxygen is added or substracted to/from the atmosphere. Since 1990 oxygen levels are measured with sufficient accuracy to detect a deficit of oxygen use from fossil fuel burning. That must be caused by the production of about 2 GtC, which released the extra oxygen.
Other sources or sinks of oxygen than vegetation and derivatives (humans… just part of the C and O cycles) are minor compared to vegetation.
– Past temperature cycles did lead to corresponding CO2 changes at different time scales. Short term, about 2-4 ppmv/°C, long term 8-10 ppmv/°C.
For short-term changes, the upper oceans are surely involved, as good as vegetation. For the oceans both directions of the flows are changed: increased temperatures increase the pCO2 of surface water, which results in more release at the warm side and less uptake at the cold side of the oceans. The result is less clear for vegetation, but in general one can expect more CO2 uptake with higher temperatures (more towards the poles). But in general, the oceans win in this case. That are the short term fluctuations we see. The long term changes may involve the deeper ocean temperatures and/or flows, which gives larger changes of CO2 for a similar temperature change.
You can find similar CO2/temp ratios if you use global (sea+land), sea only or UAH lower atmosphere temperatures. That changes the ratio’s in absolute figures, which may play a role. For the Vostok ice core (8 ppmv/°C) this is in fact compared to the calculated SH ocean temperatures (via dD and D18O measurements).
Anyway, whatever the (semi) global temperature you take, the effect of temperature on CO2 levels is surprisingly linear, despite many underlying processes are far from linear.
That is also the case for seasonal temperature changes: Both temperature and CO2 levels form more or less nice sinusoids, but maintain their ratio over the cycle (with some small lag for CO2).
About temperature and flows/levels:
The first effect of temperature on ocean CO2 flows is to increase the outflows and decrease the inflows. That is a result of the increased pCO2 in the oceans vs. a steady pCO2 of the atmosphere (assuming no emissions).
But because of the change in flows, oceanic CO2 start to accumulate in the atmosphere. That leads to an increased pCO2 of the atmosphere, until the average pCO2 of the oceans and the atmosphere are again in equilibrium (at a higher level than before). This is a quite rapid process (for the upper oceans), but much slower for deep ocean temperature changes, which results in the above differences in ratios for short term and long term temperature variations…
I agree with you that a simple explanation is the best thing to do. But that is not that simple to make. I started a web page (yet far from ready), to explain that the “background” CO2 levels measured at Mauna Loa and other base stations have a real, global meaning. But even such a simple topic costs a lot of work (and even isn’t believed by several sceptics, who still think that the data are manipulated)…
See: http://www.ferdinand-engelbeen.be/klimaat/co2_measurements.html
And this kind of debates is necessary, but slows down the work at the web page…
Demesure,
As long as the emissions are larger than the increase in the atmosphere, there is not the slightest addition in mass from all natural flows together. If there was increased upwelling from the oceans, that need to be compensated by increased downwelling at the other side of the ocean, or increased uptake by vegetation. It doesn’t matter where the flows go, even if hundreds of flows change at the same moment: the only hard fact (within the limits of accuracy of emissions and CO2 measurements) is that the sum of all natural flows together over a year and over 50 years is negative.
That doesn’t solve the “missing link” mystery. But that is a mystery, exactly because we have a quite accurate overall mass balance, even if we don’t know the exact flows in/out nature.
Your position is the same as Richard’s: we don’t know the exact flows in nature, thus we can’t know which causes the increase of CO2 in the atmosphere.
My position is that we know that the sum of all natural flows was negative over near all of the past 50 years, thus nature has not added anything to the mass of CO2 in the atmosphere, thus the only cause (besides temperature) are the emissions.
Even if we assume that an unknown source that is producing CO2 it does not follow that the CO2 levels atmosphere would increase as much as they had if humans were not pumping the excess CO2 into the air since the human produced CO2 must go somewhere.
If one wants to argue that human CO2 is not causing the increases then one must show that some sort of feedback system exists that regulates the amount of CO2 in the atmosphere (i.e. the natural sources/sinks adapt dynamically to ensure that the CO2 level stays at some ‘set point’ which could change over time). If such a feedback system existed then one could argue that the sources of CO2 would increase (or sinks decrease) if humans were not adding CO2 to the atmosphere.
So the question becomes: does the data support the idea that nature tightly regulates the amount of CO2 in the air?
If such a mechanism exists then we must assume the set point is monotonically increasing since that is what we observe. We also must assume that this mechanism is not driven by year by year temperature variations like El NInos (i.e. El Ninos like humans simply add perturbations that must be absorbed).
A test for this mechanism would add the ENSO perturbation and the human perturbation and look for evidence that the climate system responds. For example, a large ENSO+human spike should cause an opposite response. This opposite response would lag the spike and should be observed as an undershoot in the following year (i.e. the climate seems to absorb more CO2 than would be expected given the temps+human emissions).
People with more up to date experience with control systems may have better ideas on how to test for the presence of a feedback mechanism that regulates the quantity of CO2.
I still I want to see that WWII bump vs. Postwar recession CO2 trough.
And if fuel consumption and industrial production dropped by a third or even more during the Great Depression that CO2 output only dropped under 20% and only very briefly. History seems to conflict with the ice core measurements.
But I still agree with Ferdinand and others as follows:
What I can’t seem to get away from is the exchange factor.
Every exchange factor between Atmosphere and Soil/Vegetation (even including agriculture) or Sea is negative but one. There is only one positive factor: Industry puts out 6.3 BTMC and absorbs ZERO. And 3.1 BMTC currently accumulates yearly in the atmosphere.
How do you get away from that? I still don’t see how the scale or the variuability affects this whatever.
I dispute the alleged effect CO2 is supposedly having. (Ferdinand and others have also questioned what effect it has).
My current guess is that there has been a very modest tempoerature increase since 1979 that has been heavily influenced by recently introduced heat sink and waste heat causing incorrect data.
[…] Spencer Pt2: More CO2 Peculiarities – The C13/C12 Isotope Ratio 28 01 2008 NOTE: This post is the second in the series from Dr. Roy Spencer of the National Space Science and Technology Center at University of Alabama, Huntsville. The first, made last Friday, was called Atmospheric CO2 Increases: Could the Ocean, Rather Than Mankind, Be the Reason? […]
I need to retract my contention that the correlation in Figure 4 is amplified by the linear detrending. The “bend” in the CO2 graph does not carry through to the residuals (and of course Figure 4 graphs the residuals from the trend line, not raw emissions). In fact, the within year temperature effect has been depressed by its linear detrending – the superimposed pattern of temperature residuals of too positive at the beginning and end and too negative in the middle suppresses part of the signal. If we allow for the curve in the temperature trajectory (which I did by including a quadratic term) then the r-squared between “emission” and temperature residuals jumps from 0.23 to 0.34 and the sensitivity increases to over 6000 MtC per degree C.
This of course strengthens your conclusion that there is enough power in whatever influences annual fluctuations in temperature and carbon dioxide increase to explain their long term linkage as seen in both trends. but of itself, it does not unequivocally say which is cause and which is effect.
Max Beran,
Even with a 6000 Mt/°C, that is about 3 ppmv/°C (I calculated 2-4 ppmv), that doesn’t change the trend, as that is a two-way reaction on temperature. After the 1998 El Niño we had a 1999 La Niña. After that the trend did go back to around the average. After the 1992 Pinatubo, in 1993, temperatures returned to the “normal” trend. Thus the average influence of temperature on the trend is near zero.
If we may assume that the short term CO2/temp ratio and the longer term ratio are the same, then the 0.6°C increase in the period 1959-2004 has increased the CO2 level with 1.8 ppmv, while the observed increase is 60 ppmv… Even if we use the long term ratio (10 ppmv/°C for MWP-LIA), then the influence of temperature over the whole period is only 6 ppmv.
What one may not forget is the difference in scale between the different influences: There is a continuous trend of now 30% extra CO2 in the atmosphere, while humans have added about 60% more CO2. And we have seasonal to interannual variations, which are within +/- 1% (interannual) to +/- 3% (seasonal) of the CO2 levels. I don’t see how a small two-way variation can influence the trend itself (except for a small temperature contribution), besides their short-term influence on trend speed.
“The ability to model the carbon cycle in such a variety of ways means that according to the available data
(1) the cause of the recent rise in atmospheric carbon dioxide concentration is not known,
(2) the future development of atmospheric carbon dioxide concentration cannot be known, and
(3) any effect of future anthropogenic emissions of carbon dioxide on the atmospheric carbon dioxide concentration cannot be known.”
Thus according to the assertions we return at least 50 years back (and btw we could also save billions of $ of misdirected research…. write to Dubya or his successor, to Gordon Brown, to XXXX,… for saving lots of taxpayer money)… but, assuming that those propositions come out of personal thoughts, i.e. are seriously validated (and as such would deserve a true Nobel, isn’t it ?)… we are literally in the fog, and assuming that the anthro emissions have negligible impact would be no more than an act of faith. OK for me, I love accelerating in the fog and at the end the paradise is, but I wouldn’t impose such risk to an unwilling passenger… So, inch’Allah ?
Yves
We still have a few outstanding questions here…
To begin with:
Evan Jones:
<blockquote.I have noticed that when you but the ice core CO2 data into the air-measured CO2 there is a bigass divergence. You don’t need a PhD in snowballs to see that.
The air measures purport to start where the ice cores leave off. But is that raw or some funky adjustment to paste the ends together and make it look pretty? One thing is for sure: the air measure sure swoops off a heck of a lot faster than the ice cores!
I suppose that you have read that allegation, made by Jaworowski. But you better use a bit of salt with what he says. To make it clear: nobody ever has “but” the ice core data and atmospheric data together, without counting the layers for ice (which is the age at closing depth) and the CO2 level changes in firn (which give a nice trend from atmospheric to closing depth). The latter gives an idea of the gas age at closing depth (together with several other tests), as we have an overlap of about 20 years between ice bubble ages at Law Dome and South Pole atmospheric measurements.
See the following graphs (all from the Etheridge Law Dome measurements):
CO2 measurements in firn and ice with depth:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_firn.jpg
Overlap of SP air CO2 and ice CO2 levels:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_sp_co2.jpg
CO2 over 1,000 years (see the influence of the MWP and LIA, and of anthro emissions:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_1000yr.jpg
(will make a better scan, this one is blurred)…
Derek (18 Jan) :
Although the oceans exchange about 90GtC/season and vegetation about 60 GtC/season, most is turnover and the net change over a year is only -3 +/- 2.5 GtC (thus a net sink) over a trend, and the sink is increasing, while the emissions and the trend are increasing in time.
The 1992 Pinatubo cooling and the 1998 El Niño warming caused a decrease and an increase in trend (not in absolute value), of about 6 GtC/°C or 3 ppmv/°C. The total temperature increase 1959-2004 was 0.6°C, thus only 1.8 ppmv is caused by more ocean outgassing, the rest is from anthro emissions…
The trend of CO2 level is related to the quantity of CO2 released in the atmosphere. In fact, it doesn’t matter if you do that for one year, or ten years or 50 years: in all cases (with an ever increasing emission) you will find an increase more or less in ratio with the emissions, but more variability for shorter periods, as some years are warmer or colder than others, causing a temporarely variation in increase speed.
Spread over several years, the variations level out and in average reach near zero around the trend. That is clearly visible in graph nr.3 of Dr. Spencer in the introduction: The straight black line is the trend, the red one the emissions and the difference between both is the net sink in the oceans and/or vegetation.
Thus the emissions over 12 years (1990-2002) or 4 years (2003-2006) and the increase of CO2 levels over the same periods are thightly correlated, no matter how many years you group together.
The 4% you heard of is the increase in absolute level (about 370 ppmv) since 2002. The 20% is the increase in additional CO2 levels over a period of in average 8 years, caused by emissions increasing by 22% over the same time span…
Evan Jones (28 Jan),
About the Great depression: even if the industrial use of fossils fuels dropped about 30%, household heating still needed fuel (although maybe mostly wood?), thus a 20% drop in total seems reasonable…
I have plotted the Law Dome data (available at: http://cdiac.ornl.gov/trends/co2/lawdome.html ) here:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/law_dome_co2.jpg
As you can see, there is a peak around 1940 and a reduction thereafter. If you take into account that the ice core CO2 is smoothed (with about 5 years for LD 1 and LD 2, more for LD 3 and much more for Siple Dome, which were drilled in shallower ice layers), then we see a peak and reduction of about 1 ppmv CO2 1940-1945, which is within the accuracy of the measurements (+/-1.2 ppmv). The variation in emissions even is much smaller: about 0.1 ppmv. The emissions/yr simply are too small to be measured in ice cores, only after at least 3 years, the signal is better than the accuracy…
Emission figures (year/GtC):
1935 1.0
1936 1.1
1937 1.2
1938 1.1
1939 1.2
1940 1.3
1941 1.3
1942 1.3
1943 1.4
1944 1.4
1945 1.2
1946 1.2
1947 1.4
1948 1.5
1949 1.4
1950 1.6
It is only after 1950 that fossil fuel use increased rapidely.
Thanks for the figures. I will chew on this for a bit.
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