Correlation of Net CO2 emissions with climate properties shows that the growth in CO2 may be natural
Story submitted by WUWT reader Steve Brown
The narrative of the catastrophic anthropogenic global warming has been challenged at many levels but this presentation by Professor Murry Salby, Chair of Climate at Macquarie University rips up the very foundations of the story.
The talk (in the video below) was given at the Sydney Institute 2nd Aug 2011
He elegantly shows that there is a solid correlation between natural climate factors (global temperature and soil moisture content) and the net gain (or loss) in global atmospheric content when the latter is averaged over a two year period. The hanging question remains, if natural factors drive more than 90% of the growth in CO2 how significant is the contribution of human generated emissions. The answer is simple… not very.
The talk has been covered in the past on Judith Curry’s blog, and an abstract of the talk is here . But this is the first time I have encountered a video of the talk or been able to see the slides which he referenced.
Fascinating.
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Colin said (April 19, 2012 at 8:00 pm):
“I used … the assumption that 50% of our CO2 is adsorbed into natural sinks. If you use 40%, you will find that the natural variation would have a total impact of about-4.6ppm.”
Does that mean you assumed that a proportion of anthropogenic CO2 emissions (40% or 50%) are immediately taken up by natural sinks and thereafter none of the atmospheric CO2 from those emissions are adsorbed?
“Look up the phrases “partial pressure” and “Henry’s Law”, then come back when you have learned that the solubility depends on the partial pressure and that the density of water is irrelevant”
The density of water becomes relevant as regards the much larger energy content than air.
The temperature effect on absorption capability for the more dense water is likely to outweigh any pressure effect in the much less dense air.
I want to see empirical evidence that the effect of the increase in CO2 in the air more than outweighs the effect of warmer water temperatures as regards CO2 absorption / emission rates.
Simply referring to Henry’s Law is irrelevant as only half the story.
Which process dominates out in the real world ?
Evidence please.
“Explain to me how long-term fluctuations are more or less than the sum of the short term fluctuations for the short time periods that comprise the long-term period.”
Two or more separate processes operating on different timescales ?
For example, short term fluctuations driven by seasonal changes and ENSO variability as against longer term solar variability on a millennium timescale affecting cloudiness, albedo and the amount of energy getting into the oceans.
Several of you are arguing the “material balance argument” which has been well-ventilated here and elsewhere between Ferdinand Engelbeen (for) Richard Courtney (against). I agree Richard on this question. This is not a static situation where a “bank balance” argument works.
In my opinion, it is more likely a series of dynamic time cycles, in which CO2 lags temperature at ~~1000 years on a long cycle, and ~9 months on a short cycle, and there are possibly other intermediate cycles as well that are not documented (the late Ernst Beck thought there was at least one intermediate cycle with a lag of ~~5? Years, as I recall).
This discussion has been ongoing since 2008 and earlier. Here is a more recent post.
___________
http://wattsupwiththat.com/2012/04/06/a-reply-shakun-et-al-dr-munchausen-explains-science-by-proxy/#comment-948287
RobRoy says: April 6, 2012 at 8:49 am
“It is my layman’s understanding that seawater, as it warms, releases CO2 dissolved therein. As seawater warms its ability to keep CO2 in solution decreases. This leaching of CO2 as the oceans warm is a great explanation for the correlation between temperature and atmospheric CO2 concentration. It explains why CO2 lags warming. Warming first then atmospheric CO2 increase. This is provable in a laboratory..”.
____________
First of all Rob, you are possibly on the right track – see Henry’s Law (1803) and the bit about temperature.
http://en.wikipedia.org/wiki/Henry's_law
Next, Shakun et al is nonsense. The paper is a veritable cornucopia of apples and oranges, grapes and bananas – and let’s not forget the watermelons.
It is interesting how often the global warming alarmists choose to ignore the Uniformitarian Principle AND Occam’s Razor.
CO2 lags temperature at all measured time scales from ~~600-800 years in the ice core records on a long temperature-time cycle, to 9 months on a much shorter time scale.
http://icecap.us/images/uploads/CO2vsTMacRae.pdf
We really don’t know how much of the recent increase in atmospheric CO2 is natural and how much is manmade – possibilities range from entirely natural (~~600-800 years ago was the Medieval Warm Period) to entirely manmade (the “material balance argument”). I lean towards mostly natural, but I’m not certain.
Although this questions is scientifically crucial, it is not that critical to the current “social debate” about alleged catastrophic manmade global warming (CAGW), since it is obvious to sensible people that IF CO2 truly drives temperature, it is an insignificant driver (climate sensitivity to CO2 is very low; “feedbacks” are negative) and minor increased warmth and increased atmospheric CO2 are both beneficial to humanity AND the environment.
In summary, the “climate skeptics” are trouncing the warming alarmists in the “mainstream CAGW debate”.
Back to the crucial scientific question – is the current increase in atmospheric CO2 largely natural or manmade?
Please see this 15fps AIRS data animation of global CO2 at
http://svs.gsfc.nasa.gov/vis/a000000/a003500/a003562/carbonDioxideSequence2002_2008_at15fps.mp4
It is difficult to see the impact of humanity in this impressive display of nature’s power.
All I can see is the bountiful impact of Spring, dominated by the Northern Hemisphere with its larger land mass, and some possible ocean sources and sinks.
I’m pretty sure all the data is there to figure this out, and I suspect some already have – perhaps Jan Veizer and colleagues.
Thylacine
Co2 absorption by the oceans and outgassing from them isn’t a simple either/or question. There are two processes at work. And they don’t operate at the same rate. Adding CO2 to the atmosphere results in an imbalance between air and ocean concentrations, tending to move CO2 into the oceans – this is a way, way simplified description of the chemistry of this process.
Competing with this is the fact that warmer water tends to hold less gas in solution, including CO2. But warming of the oceans happens much more slowly than increases in CO2 in the atmosphere.
So in the Ice Age situation there wasn’t an extra source of CO2 in the form of Fossil Fuels. So the temperature effect is what predominates.
In our current situation, the rate at which CO2 is being added to the atmosphere by human activity is the factor that predominates.
lazyteenager~
As of April 5th, CO2 is 394.45 PPM http://co2now.org/ (an alarmist page)
And you are saying 450?
FAIL.
Where are these numbers from?
The little gadget there in the right hand column says 392 ppm currently.
Blade says:
April 20, 2012 at 3:13 am
“”LazyTeenager [April 19, 2012 at 8:34 pm] says:
Currently we are above 450ppm.”
”
Where are these numbers from?
The little gadget there in the right hand column says 392 ppm currently.”
His alarmism is getting the better of him. Duck, he’s about to gleick.
By emitting 8 GT a year we increase CO2 partial pressure by a certain amount, increasing the speed of adsorption into the ocean. If we stopped emitting CO2, the balance of adsorption and outgassing would shift. It’s a dynamic process, not some simple fixed sums.
Some of the posts seem to assume that the release of CO2 by the oceans is the converse of absorption. Surely they are two quite different processes. The release of CO2 is caused by cold water from the deep oceans reaching the surface where excess CO2 is released. In contrast CO2 is scavanged from the atmosphere by organisms like plankton and crustacea. They, or their preditors, die and sink to the bottom. Thus the atmosphere and the oceans will naturally experience a gradual decline in CO2 which, over millions of years, has declined from many thousand parts per million to the few hundred we see today. I can only assume that the reason we have never reached the 150ppm where photosynthesis effectively stops is due to volcanos and presumeably some anaeobic processes in the deep oceans which pumps CO2 into the cold water that eventually releases it back into the atmophere when it reaches the surface. If I am right the balance of CO2 will be largely dependent on the fequency and power of el ninos added to the phase of the AMO and PDO. We are currently adding to this release but, as the lecture points out, it is a very small change and we, as yet, do not know if this will be significant compared with the variation in natural sources and sinks. That is the message I got and it is a very important one.
Allan McRae wrote:
“Several of you are arguing the “material balance argument” which has been well-ventilated here and elsewhere between Ferdinand Engelbeen (for) Richard Courtney (against). I agree Richard on this question. This is not a static situation where a “bank balance” argument works.”
Who is Richard Courtney?
What you say is equal to saying that first principles, in this case the conservation of mass, do not always apply.
Any change in the balance of the atmospheric carbon dioxide mass needs to be accounted for by the same change in the sum of all the flux terms.
dMc is the change in the total CO2 molar ratio in the atmosphere.
dMc = Fin(a) + Fin(n) – Fout(n)
(Approximations for present day: dMc = 2.4 ppm/a; Fin(a) = 4 ppm/a)
where Fin(a) is the total flux from anthropogenic sources to the atmosphere, Fin(n) the total flux from natural sources to the atmosphere, and Fout the total flux into the natural sinks (ocean/biosphere).
If dMc < Fin(a), like it is the case in present day, then
dMc – Fin(a) = Fin(n) – Fout(n) < 0
If follows that
Fin(n) < Fout(n)
The CO2 mass flux from natural sources to the atmosphere must be smaller then the CO2 mass flux from the atmosphere to natural sinks in present day (with dMc = 2.4 ppm/a and Fin(a) = 4 ppm/a).
q.e.d.
First principle must apply. Always. "Dynamic time cycles" can't help you with going around this.
There are a lot of problems with Salby’s theory but the biggest and easiest to show is simple accounting.
Humanity is releasing around 30 billion tonnes of carbon to the atmosphere per year. The observed increase of carbon in the atmosphere is however only 15 billion tonnes. Now unless Salby has overturned the conservation of mass and found a way to make 15 billion tonnes of carbon disappear into nothing, or reinvented arithmetic so that 30 billion minus 15 billion isn’t 15 billion, that means that 15 billion tonnes of carbon is being removed from the atmosphere each year by the fast carbon cycle (evidence shows mostly by dissolution in the oceans).
If natural sinks are removing roughly half the carbon we emit to the atmosphere, as simple conservation of mass demands, that is exactly the opposite of what Salby is proposing. Instead of being the cause of the increase of carbon dioxide in the atmosphere, natural processes are in fact acting to moderate it ie without the action of natural carbon sinks the rate of increase of carbon in the atmosphere would be twice what it is, the full 30 billion tonnes/yr.
As usual in science things don’t rely on just one line of evidence though, even if this one is the most compelling. Multiple independent lines of evidence must support a theory.
Perhaps the most elegant is that atmospheric oxygen has declined at the rate one would expect from burning fossil fuels. One would not expect such a decrease in oxygen from natural carbon emissions.
Another compelling independent line is that shown by the decrease in carbon-14 in the atmosphere. C-14 is formed high in the atmosphere, where it forms a minuscule but measurable proportion of carbon atoms, and is taken up by plants just like the other isotopes of carbon. However, it has a half-life of 5730 years and so old organic carbon is depleted in C-14 relative to new organic carbon (hence why carbon dating works). Fossil fuels are so old there is essentially no C-14 left in them. A decrease in the proportion of C-14 in the atmosphere shows that the extra carbon has come from an “old” source ie fossil fuels rather than a “new” one.
To paraphrase my science teacher, maybe Salby has overturned the laws of physics, chemistry and mathematics. If he has, let him publish his results and book his ticket to Stockholm, but first perhaps he should check them thoroughly.
Lastly, Salby contradicts his own theory and doesn’t even seem to notice when he notes that the rate of increase of CO2 in the atmosphere has continued to climb in the last decade while temperature increase has slowed. If, as Salby proposes, CO2 increase was caused solely by increasing temperature then surely CO2 increase should have slowed? Given his theory of a 120ppm CO2 increase for each 0.8C rise in temperature, when average temperatures were 4-6C lower during the last glacial maximum, atmospheric CO2 must have been minus 207-507ppm! Now we know Salby doesn’t care for the ice-core record of CO2 as it doesn’t agree with his theory (it in fact gives about 180ppm), but how exactly does he propose life continued without any CO2 in the atmosphere at all?
Jan P. Perlwitz says:
April 20, 2012 at 4:49 am
“If follows that
Fin(n) < Fout(n)
The CO2 mass flux from natural sources to the atmosphere must be smaller then the CO2 mass flux from the atmosphere to natural sinks in present day (with dMc = 2.4 ppm/a and Fin(a) = 4 ppm/a).
q.e.d.
First principle must apply. Always. "Dynamic time cycles" can't help you with going around this."
Okay, again in simple words for GISS employees:
Fin(n) and Fout(n) are not natural constants.
What’s the point of making the video semi-private? It won’t stop the Zwickian 451 firemen, but it does stop people who aren’t interested enough to get through the fence of linkages. The pseudo-science side is instantly heard any time you turn on any radio or TV or look at any magazine. It’s not wise to make the scientific side so hard to reach.
Stephen Wilde wrote:
“It would appear that the ice core record is too coarse to reproduce the atmospheric CO2 changes during the 1000 year cycle from MWP to LIA to date.”
This was the graphic with the data, which I referenced.
http://cdiac.ornl.gov/trends/co2/graphics/lawdome.gif
Apparently you didn’t even bother to look at it. You just come up with excuses why the data should be dismissed.
“Trends
The atmospheric CO2 reconstructions presented here offer records of atmospheric CO2 mixing ratios from 1006 A.D. to 1978 A.D. The air enclosed in the three ice cores from Law Dome, Antarctica has unparalled age resolution and extends into recent decades, because of the high rate of snow accumulation at the Law Dome drill sites (Etheridge et al. 1996). Etheridge et al. (1996) reported the uncertainty of the ice core CO2 mixing ratios is 1.2 ppm. Preindustrial CO2 mixing ratios were in the range 275-284 ppm, with the lower levels during 1550-1800 A.D., probably as a result of colder global climate (Etheridge et al. 1996). The Law Dome ice core CO2 records show major growth in atmospheric CO2 levels over the industrial period, except during 1935-1945 A.D. when levels stabilized or decreased slightly.”
(http://cdiac.ornl.gov/trends/co2/lawdome.html)
Well, you seem to do the thing with the hypothesis and the data the other way around. You test the data with the hypothesis. If the data are in contradiction to the hypothesis, you conclude the data must be wrong.
Why do people think that CO2 having been created will remain for ever. Plant life all over the globe, land and ocean, is busy converting CO2 gas to solid hydrocarbons. The more CO2 in the atmosphere the faster they convert it.
DirkH:
“Okay, again in simple words for GISS employees:
Fin(n) and Fout(n) are not natural constants.”
Your statement does not contain any argument. Of course, they are no constants. Who says they were? Since when does the mass balance equation only needs to be fulfilled, if one, some, or all of the terms were constants? The mass balance equation is one of the most fundamental equations in physics. Like the energy balance equation. The time dependence of the various terms in it doesn’t change this.
Really astonishing stuff. There’s still the question of levels of CO2 during earlier warm periods, though. Plant stomata here comes to the rescue and gives higher (and presumably better) estimates than the problematic ice core records. Plant stomata from the Eemian also give slightly higher CO2 levels than ice cores, but still only up to about 300 ppm: http://www.geol.lu.se/personal/msr/bjerknes.pdf
The argument is not pointless, but I will agree that it is not the one which will drive a stake through the heart of AGW. Unless and until the two time series start to diverge substantially in morphology, the superficial resemblance will be enough to convince most people that there is a cause and effect relationship.
Well said, Bart. One could go further and note that the function one is plotting is almost certainly multivariate, not single variable, which makes things far worse because your argument applies for each variable for which the superficial relationship exists, and because one then can actually choose which of them to emphasize when making the fit. Correlation is not causality, but often it is all we have, and we’re used to using the former to infer the latter even when we cannot really directly prove it. However, having multiple variables, and having causal relationships and covariance among those variables, is a ripe opportunity for omitted variable fraud — ignoring the other variables to focus attention on the correlation associated with the single variable we want to be the cause.
However, it isn’t really necessary to wait until the two time series diverge in the future, because they already diverge in the past. CO_2 as a sole driver is a lousy explanation — so far — for the climate variation observed over the last 5 million years, let alone the last 600 million. Furthermore, trying to analyze the dynamics of CO_2 balance in the atmosphere over a geological past where atmospheric CO_2 spent hundreds of millions of years at concentrations over 1000 ppm (or one part per thousand, a tenth of a percent or more!) is enough to give one a headache. CO_2 is sequestered in the oceans, in the soil, in the crust, carbon in various organic (non-CO_2) forms is bound up in rocks, in clathrates, in oil and gas and coal deposits. Because biology steadily and “irreversibly” depletes carbon (reversibly only on truly long time scales) without an equally steady source CO_2 levels would drop to where plant biology itself becomes rate limiting. This may have in fact happened at the coldest parts of the last glacial period.
Carbon dioxide does not explain the variability of the climate over paleontological time. It does not explain the variability of the climate over recent paleontological time, e.g. the Holocene. It might be a proximate cause associated with the recent gradual return to ice age conditions 3 million years ago, if long time scale modulation of e.g. volcanic and crustal CO_2 sources (one of the only sources of “new” carbon to replenish that which the biosphere steadily depletes) is a reality, but I find it difficult to assess this given the enormous and somewhat violent disagreement concerning just how much CO_2 is being released now by crustal activity. One group asserts that it is a tiny fraction of human emissions. Other groups point to studies that suggest that it is larger than human emissions (including studies that predate the CAGW controversy, which I am more inclined to believe but assessing bias of this sort is very difficult for a non-expert).
What is certain is that there is a lot of carbon bound up in the dynamic biosphere, and a lot more passively bound into the ocean, and still more bound into the soil and the Earth’s crust, and that many factors affect the way that carbon is moved around as CO_2 or otherwise. It may well be that the greatest impact humans have had on the CO_2 levels of the atmosphere comes from deforestation and land use changes, not from burning fossil fuels, and it may yet be that humans are still not the largest factor in the observed changes.
What is certain is that even when the CO_2 levels were as high as they are projected to rise over the next century if nothing at all is done about them, the Earth did not experience a climate catastrophe. It did, however, experience a serious climate catastrophe the last time CO_2 levels where close to half what they are now — ice age and a perilous dance between land-based plant die off and CO_2. Indeed, it may be that the progressive loss of land flora in ice ages may be the negative feedback that ultimately prevents snowball Earth — the cold increases until biological uptake by photosynthesizing plants cannot match e.g. crustal production of CO_2 and a dynamic equilibrium of sorts is reached. Without new CO_2 the very real greenhouse effect could easily have a negative “catastrophe”, and ice ages might well be the biological/geologically stable cold phase that persists until events that de-sequester large amounts of the stored carbon occur, e.g. increases in volcanism, warming that degasses the oceans and soils.
Calling all of this settled science is a bit of a joke, and trying to look at 200 or 300 years of data and interpreting two generally upward trending curves with very different patterns of fluctuation is proof of cause is a much bigger joke, when those patterns are not persistent and do not explain much larger excursions in the still recent geological past. The data suggest that CO_2 is probably responsible for just about the minimum warming that the GHE theory predicts, that overall climate sensitivity is neutral or even negative, and that something else is responsible for most of the temperature variation observed over geological time scales.
I have yet to see truly convincing data and physical arguments to explain the latter. There is a tantalizing very long time scale correlation between cosmic ray flux and geological temperature over the last 600 or so million years, back to the limits of what we can infer using biologically derived markers in combination with radioactives, but this is hard going and not necessarily clear. There are variations in other proxies (including CO_2) that have some degree of synchronicity with this, but identifying cause and effect is difficult.
One thing that does indeed seem to be a possibility is that if we did reach 1000 ppm of atmospheric CO_2, this might be enough to re-stabilize a warm phase and put an end to the current ice age, so that the Holocene does not end but just keeps on going, as the Earth warms back up to the 1-2C warmer temperatures it had 5 million years ago and which appears to be the stable upper bound of geological temperatures on Earth. However, I suspect that the biosphere and oceanic sinks will not permit the CO_2 levels to remain that high unless whatever natural source was responsible for the high levels observed over most of the last 600 million years comes back into play.
rgb
“Why do people think that CO2 having been created will remain for ever. Plant life all over the globe, land and ocean, is busy converting CO2 gas to solid hydrocarbons. The more CO2 in the atmosphere the faster they convert it.”
I’m not aware of any science saying CO2 will last forever. In fact, the fact that half the CO2 we emit burning fossil fuels is removed by nature is precisely what proves Salby wrong. We put 30 billion tonnes of carbon into the atmosphere yet the amount of carbon in the atmosphere only increases by 15 billion tonnes per year – the other 15 billion is taken up by nature. Salby claims the opposite – that nature is causing the increase in carbon in the atmosphere.
If the increase from 280ppm before the industrial revolution to 393ppm today was due to natural sources then what happens to our 30 billion tonnes per year?
http://wattsupwiththat.com/2012/02/29/climate-deniers-are-giving-us-skeptics-a-bad-name/#comment-909729
Excerpt for perwitz:
I think Ferdinand’s “material balance argument” is incorrect because it inherently assumes that the climate-CO2 system is static, but it is dynamic, and the relatively small humanmade fraction of total CO2 flux may not be significant in this huge system, as it continues to chase equilibrium into eternity.
“This number is somewhat higher than the measured 392ppm by volume, but since CO2 is heavier than air, this makes sense, at least to me.”
And I am afraid only to you 😉
ppm = parts per million. It is irrelevant what the parts are made of, it is a statement as to their number. If I tell you I got 10 coins in my wallet, they will still be ten coins, even if you learn that 5 are Euro coins and 5 are Cents – the fact that the Euros are way havier than the Cents does not magically increase their number in the mix.
– as explained right in the first comment 447ppm by MASS, 392ppm by VOLUME as CO2 is heavier than air on average.
– also note the 392ppm is pretty suspect anyway as it’s a guess from measuring one area, it’s not like the whole atmosphere has been measured. (the 447ppm was a calculation)
That the rise in atmospheric CO2 is purely anthropogenic in origin is demonstrated by the fact that atmospheric CO2 levels are rising more slowly than cumulative anthropogenic emissions, which established beyind reasonable doubt that the natural environment is a net carbon sink. This means that the natural environment annually takes in more CO2 than it emits, and hence is opposing the rise in atmospheric CO2, not causing it.
It is well known that the annual change in atmospheric CO2 is correllated with ENSO for example, because change in ocean temperature causes change in the growth and dieback of terrestrial biota and becuase it affects the exchange of CO2 with the surface ocean. However this does not explain the long term rise in atmospheric CO2, just the inter-annual variability superimposed on top.
– just make that clear the entire CO2 pattern comes from that one measuring station in Hawaii.
Alan MacRae, Ferdinand’s argument does not assume that the carbon cycle is static. Look at the mass balance diagram on his website and you will see that the inferred fluxes are constantly changing.