From the University of Virginia, comes yet another incomplete press release that doesn’t give the name of the paper or the DOI:
Salt marsh carbon may play role in slowing climate warming, study shows
A warming climate and rising seas will enable salt marshes to more rapidly capture and remove carbon dioxide from the atmosphere, possibly playing a role in slowing the rate of climate change, according to a new study led by a University of Virginia environmental scientist and published in the Sept. 27 issue of the journal Nature.
Carbon dioxide is the predominant so-called “greenhouse gas” that acts as sort of an atmospheric blanket, trapping the Earth’s heat. Over time, an abundance of carbon dioxide can change the global climate, according to generally accepted scientific theory. A warmer climate melts polar ice, causing sea levels to rise.
A large portion of the carbon dioxide in the atmosphere is produced by human activities, primarily the burning of fossil fuels to energize a rapidly growing world human population.
“We predict that marshes will absorb some of that carbon dioxide, and if other coastal ecosystems – such as seagrasses and mangroves – respond similarly, there might be a little less warming,” said the study’s lead author, Matt Kirwan, a research assistant professor of environmental sciences in the College of Arts & Sciences.
Salt marshes, made up primarily of grasses, are important coastal ecosystems, helping to protect shorelines from storms and providing habitat for a diverse range of wildlife, from birds to mammals, shell- and fin-fishes and mollusks. They also build up coastal elevations by trapping sediment during floods, and produce new soil from roots and decaying organic matter.
“One of the cool things about salt marshes is that they are perhaps the best example of an ecosystem that actually depends on carbon accumulation to survive climate change: The accumulation of roots in the soil builds their elevation, keeping the plants above the water,” Kirwan said.
Salt marshes store enormous quantities of carbon, essential to plant productivity, by, in essence, breathing in the atmospheric carbon and then using it to grow, flourish and increase the height of the soil. Even as the grasses die, the carbon remains trapped in the sediment. The researchers’ model predicts that under faster sea-level rise rates, salt marshes could bury up to four times as much carbon as they do now.
“Our work indicates that the value of these ecosystems in capturing atmospheric carbon might become much more important in the future, as the climate warms,” Kirwan said.
But the study also shows that marshes can survive only moderate rates of sea level rise. If seas rise too quickly, the marshes could not increase their elevations at a rate rapid enough to stay above the rising water. And if marshes were to be overcome by fast-rising seas, they no longer could provide the carbon storage capacity that otherwise would help slow climate warming and the resulting rising water.
“At fast levels of sea level rise, no realistic amount of carbon accumulation will help them survive,” Kirwan noted.
Kirwan and his co-author, Simon Mudd, a geosciences researcher at the University of Edinburgh in Scotland, used computer models to predict salt marsh growth rates under different climate change and sea-level scenarios.
The United States Geological Survey’s Global Change Research Program supported the research.
Contact: Fariss Samarrai fls4f@virginia.edu (and tell him to make complete press releases please)
===============================================================
After some searching, I found the paper and the abstract:
Response of salt-marsh carbon accumulation to climate change
Matthew L. Kirwan & Simon M. Mudd
- Nature 489, 550–553 (27 September 2012) doi:10.1038/nature11440
About half of annual marine carbon burial takes place in shallow water ecosystems where geomorphic and ecological stability is driven by interactions between the flow of water, vegetation growth and sediment transport1. Although the sensitivity of terrestrial and deep marine carbon pools to climate change has been studied for decades, there is little understanding of how coastal carbon accumulation rates will change and potentially feed back on climate2, 3. Here we develop a numerical model of salt marsh evolution, informed by recent measurements of productivity and decomposition, and demonstrate that competition between mineral sediment deposition and organic-matter accumulation determines the net impact of climate change on carbon accumulation in intertidal wetlands. We find that the direct impact of warming on soil carbon accumulation rates is more subtle than the impact of warming-driven sea level rise, although the impact of warming increases with increasing rates of sea level rise. Our simulations suggest that the net impact of climate change will be to increase carbon burial rates in the first half of the twenty-first century, but that carbon–climate feedbacks are likely to diminish over time.
Find two years with the same average max temperature for the same month. (It’s not very common.) Then look up the minimum.
Central England August 1898 average temperature for month 20.1°C max and 12.1 min.
Central England August 2009 average temperature for month 20.2°C max and 12.4 min.
Central England July 1882 average temperature for month 20.0°C max and 11.1 min.
Central England August 2000 average temperature for month 20.4°C max and 11.2 min.
Bobl says:
September 27, 2012 at 6:11 am
There is no difference in opinion here: CO2 emissions are increasing slightly exponential over time which leads to a slightly exponential increase in the atmosphere and a slightly exponential increase in uptake rate. The net result is that the ratio of increase in the atmosphere (the “airborne fraction”) is in remarkably linear ratio with the human emissions:
http://www.ferdinand-engelbeen.be/klimaat/klim_img/temp_co2_acc_1900_2004.jpg
and
http://www.ferdinand-engelbeen.be/klimaat/klim_img/acc_co2_1900_2004.jpg
If the human releases were steady, the CO2 levels would go assymptotical to a new equilibrium somewhere higher than the old equilibrium, just sequestering all the human emissions in quantity. And if human emissions would stop today, CO2 levels would go back to about 290 ppmv, which is the equilibrium level for the current temperature, with an e-folding rate of ~53 years (~40 years half life time)…
This paper is full of assumptions which are accepted without question — the world is warming, carbon dioxide is causing it, etc. It makes no attempt to evaluate those assumptions. It accepts the so-called ‘consensus view’ but does not actually offer any science to support that view.
Ferdinand Engelbeen:
For convenience, I am answering two of your posts to me in this post
At September 27, 2012 at 6:29 am you write
We are interested in the cause of “what happens in the atmosphere: an increase of CO2, a decrease or a steady state”.
If the error in the estimates of natural emissions completely dwarfs the magnitude of the anthropogenic emission – and they do – then it cannot be known if “what happens in the atmosphere” is a result – in whole or in part – of variations of the natural emissions.
But you assume the natural emission and sequestration have the same variation now as in the past and assert, “See the anthropogenic emission has caused the increase of CO2 in the atmosphere”. Your assumption is unjustified so your assertion is unjustifiable.
Your post at September 27, 2012 at 7:44 am implies that I do not consider both fast and slow processes in the carbon cycle. That implication is misleading because you know my view of the processes which I have repeatedly stated including on WUWT.
For clarity, I again post my view of the main processes is as follows.
Mechanisms of the carbon cycle
The IPCC reports provide simplified descriptions of the carbon cycle. In our 2005 papers
(ref. Rorsch A, Courtney RS & Thoenes D, ‘The Interaction of Climate Change and the Carbon Dioxide Cycle’ E&E v16no2 (2005) )
we considered the most important processes in the carbon cycle to be:
Short-term processes
1. Consumption of CO2 by photosynthesis that takes place in green plants on land. CO2 from the air and water from the soil are coupled to form carbohydrates. Oxygen is liberated. This process takes place mostly in spring and summer. A rough distinction can be made:
1a. The formation of leaves that are short lived (less than a year).
1b. The formation of tree branches and trunks, that are long lived (decades).
2. Production of CO2 by the metabolism of animals, and by the decomposition of vegetable matter by micro-organisms including those in the intestines of animals, whereby oxygen is consumed and water and CO2 (and some carbon monoxide and methane that will eventually be oxidised to CO2) are liberated. Again distinctions can be made:
2a. The decomposition of leaves, that takes place in autumn and continues well into the next winter, spring and summer.
2b. The decomposition of branches, trunks, etc. that typically has a delay of some decades after their formation.
2c. The metabolism of animals that goes on throughout the year.
3. Consumption of CO2 by absorption in cold ocean waters. Part of this is consumed by marine vegetation through photosynthesis.
4. Production of CO2 by desorption from warm ocean waters. Part of this may be the result of decomposition of organic debris.
5. Circulation of ocean waters from warm to cold zones, and vice versa, thus promoting processes 3 and 4.
Longer-term processes
6. Formation of peat from dead leaves and branches (eventually leading to lignite and coal).
7. Erosion of silicate rocks, whereby carbonates are formed and silica is liberated.
8. Precipitation of calcium carbonate in the ocean, that sinks to the bottom, together with formation of corals and shells.
Natural processes that add CO2 to the system
9. Production of CO2 from volcanoes (by eruption and gas leakage).
10. Natural forest fires, coal seam fires and peat fires.
Anthropogenic processes that add CO2 to the system
11. Production of CO2 by burning of vegetation (“biomass”).
12. Production of CO2 by burning of fossil fuels (and by lime kilns).
Several of these processes are rate dependant and several of them interact.
At higher air temperatures, the rates of processes 1, 2, 4 and 5 will increase and the rate of process 3 will decrease. Process 1 is strongly dependent on temperature, so its rate will vary strongly (maybe by a factor of 10) throughout the changing seasons.
The rates of processes 1, 3 and 4 are dependent on the CO2 concentration in the atmosphere. The rates of processes 1 and 3 will increase with higher CO2 concentration, but the rate of process 4 will decrease.
The rate of process 1 has a complicated dependence on the atmospheric CO2 concentration. At higher concentrations at first there will be an increase that will probably be less than linear (with an “order” <1). But after some time, when more vegetation (more biomass) has been formed, the capacity for photosynthesis will have increased, resulting in a progressive increase of the consumption rate.
Processes 1 to 5 are obviously coupled by mass balances. Our paper (4) assessed the steady-state situation to be an oversimplification because there are two factors that will never be “steady”:
I. The removal of CO2 from the system, or its addition to the system.
II. External factors that are not constant and may influence the process rates, such as varying solar activity.
Modelling this system is a difficult because so little is known concerning the rate equations. However, some things can be stated from the empirical data.
At present the yearly increase of the anthropogenic emissions is approximately 0.1 GtC/year. The natural fluctuation of the excess consumption (i.e. consumption processes 1 and 3 minus production processes 2 and 4) is at least 6 ppmv (which corresponds to 12 GtC) in 4 months. This is more than 100 times the yearly increase of human production, which strongly suggests that the dynamics of the natural processes here listed 1-5 can cope easily with the human production of CO2. A serious disruption of the system may be expected when the rate of increase of the anthropogenic emissions becomes larger than the natural variations of CO2. But the above data indicates this is not possible.
The accumulation rate of CO2 in the atmosphere (~1.5 ppmv/year which corresponds to 3 GtC/year) is equal to almost half the human emission (~6.5 GtC/year). However, this does not mean that half the human emission accumulates in the atmosphere, as is often stated . There are several other and much larger CO2 flows in and out of the atmosphere. The total CO2 flow into the atmosphere is at least 156.5 GtC/year with 150 GtC/year of this being from natural origin and 6.5 GtC/year from human origin. So, on the average, 3/156.5 = 2% of all emissions accumulate.
The above qualitative considerations suggest the carbon cycle cannot be very sensitive to relatively small disturbances such as the present anthropogenic emissions of CO2. However, the system could be quite sensitive to temperature. So, our paper considered how the carbon cycle would be disturbed if – for some reason – the temperature of the atmosphere were to rise, as it almost certainly did between 1880 and 1940 (there was an estimated average rise of 0.5 °C in average surface temperature).
As temperature rises the rate of the main CO2 production processes 2 (decomposition of organic matter) and 4 (desorption from the oceans) would rise, as would the rate of the consumption process 1 (photosynthesis). However, the rate of absorption in the ocean (process 3) will not be increased. The rates of processes 1a and 2a will rise more quickly than the rates of processes 1b and 2b, but it is not obvious which would rise most. Obviously, the net result would be an increase of CO2 production by desorption from the oceans. This is a relatively slow process, because the mass transfer coefficient between the sea water and its surface is relatively low (the rates of both absorption and desorption in the oceans have time constants that are probably of the order of decades). This would mean that a disruption by a temperature rise would result in a relatively slow increase of CO2 production. Gradually, the consumption processes 1 (photosynthesis) and 3 (absorption in cold ocean waters) will increase and slow down the excess CO2 formation.
As long as the anthropogenic production of CO2 is less than, say, 10% of the average natural production (2.5 times the present level), the CO2 level in the atmosphere might become 2.5 times higher than it was originally. However, it will eventually become much lower again, due to the delayed action of process 8 (the “true sink”).
The above considerations of available data strongly suggest that the anthropogenic emissions of CO2 will have no significant long term effect on climate. The main reason is that the rate of increase of the anthropogenic production of CO2 is very much smaller that the observed maximum rate of increase of the natural consumption of CO2.
In the light of all the above considerations it would appear that the relatively large increase of CO2 concentration in the atmosphere in the twentieth century (some 30%) is likely to have been caused by the increased mean temperature that preceded it. The main cause may be desorption from the oceans. The observed time lag of half a century is not surprising. Assessment of this conclusion requires a quantitative model of the carbon cycle, but – as previously explained – such a model cannot be constructed because the rate constants are not known for mechanisms operating in the carbon cycle.
Richard
UVA Today
Senior News Officer
Mr. Samarrai,
Your article, http://news.virginia.edu/content/salt-marsh-carbon-may-play-role-slowing-climate-warming-study-shows, contains statements regarding the mechanics of climate and carbon dioxide interactions which suggest a lack of understanding and scientific knowledge on your part. By doing so you cast needless doubt on the accuracy of the remainder of the article, the work of the researchers whom you depict, and the UVA Today image .
Carbon dioxide is not the “predominant” greenhouse gas as you claim. Water vapor is the primary greenhouse gas and is understood to account for approximately 95% of the greenhouse gas effect. Carbon dioxide makes up about 3.6 percent of the effect. The fraction of total carbon dioxide generated that is attributable to human activity is estimated at 3.22 percent. Thus human activity is estimated to contribute about 0.117 percent of the greenhouse effect…a long way from being “predominant.” “A large portion of the carbon dioxide in the atmosphere is produced by human activities”…NOT.
“A warmer climate melts polar ice, causing sea levels to rise.” Do you understand that there are two poles? If you are speaking of North polar ice (Arctic), it could all melt, as it has in the past, and there would be no change in sea level (try Googling Archimedes). The Antarctic (pole) has been adding to its total ice mass.
There has been no increase in atmospheric global temperatures for 12+ years; the rate-of-rise of sea level has recently stalled, and the longer term rate-of-rise remains stable at approximately 10-12 inches per century.
Does your “generally accepted scientific theory” include solar, solar radiation wavelength, and cosmic particle interactions?
I find it regrettable that such errors pass your editorial board.
Yours truly,
Charles Battig, MD
VA-Scientists and Engineers for Energy and Environment
Charlottesville
Now I understand. Man is Gaia’s way of freeing the precious carbon locked away where the Earth’s hungry biomass cannot reach it.
richardscourtney says:
September 27, 2012 at 8:49 am
If the error in the estimates of natural emissions completely dwarfs the magnitude of the anthropogenic emission – and they do – then it cannot be known if “what happens in the atmosphere” is a result – in whole or in part – of variations of the natural emissions
As said before, even without knowing any of the many natural emissions, we know the result: an increase of 4 +/- 2 GtC/year, that is average halve the human emissions, both in increase rate and natural variability. Thus whatever the natural emissions and sinks are, were, or varied over the (far) past, over the past 50 years nature as a whole was a net sink for CO2. That is all we need to know.
I was of course aware that you consider several processes. The problem I have is with:
It is absolutely certain that nature did not reach “a saturation point, and any extra will mostly accumulate”.
That implies that the fast processes are dominant. If that were the case, then indeed all extra CO2 would be sequestered in short time. But as only halve of the extra CO2 input is sequestered, even at 100 ppmv CO2 above dynamic equilibrium, that is not the case. The problem is that the fast processes are limited in storage capacity and the slow processes are limited in exchange speed.
Your reasoning is based on the huge exchanges which take place during the seasonal temperature swings. These are indeed huge, but limited: the global (NH+SH) temperature change over a year is about 1°C, mainly the influence of the NH (more land than ocean). The resulting global averaged CO2 swing is about 5 ppmv. Thus the seasonal temperature influence is not more than 5 ppmv/°C.
There is little indication that the seasonal amplitude changed much over the past 50 years, thus the increase of CO2 had little influence on the fast processes that govern the seasonal variation. Thus the increasing sink capacity that removes about halve of the human emissions (as mass, not original molecules), is by the slower processes. Which don’t remove the increasing CO2 excess fast enough to keep pass with the human emissions…
The total CO2 flow into the atmosphere is at least 156.5 GtC/year with 150 GtC/year of this being from natural origin and 6.5 GtC/year from human origin. So, on the average, 3/156.5 = 2% of all emissions accumulate.
Common error, heard here many times.
Take a fountain where water is pumped from a bassin at the bottom and flows back into the bassin. The pump delivers 1,000 l/minute to the fountain. Besides some evaporation and spills, no water disappears and the level in the bassin stays equal. Now the maintenance guy opens a small supply valve in the input to the fountain, delivering an additional 10 l/min of water. The resulting (measured) increase in de bassin after some time is the equivalent of 10 l/min. Thus on average only 1% of all water inputs accumulate. But still 100% of the increase is from the additional supply…
For the CO2 balance (human input increased to the current 8 GtC/year):
158 GtC/year goes in, of which 150 GtC natural and 8 GtC human. 162 GtC goes out as the current mix of natural and human CO2, all in natural sinks. Net balance: an increase of 4 GtC/year, fully caused by the human emissions, even if that is not more than 5% of the inputs (and some more % of the outputs)…
As said before, both the biosphere and the oceans are currently net sinks for CO2. I think we all agree that the biopshere is a net sink (the “greening earth”). The absolute highest increase of CO2 from the oceans is maximum 16 ppmv/°C, no matter if that water comes from the deep oceans of 800 years ago or from the surface layer today. Thus no temperature increase or decrease from the past or the present can explain the 100+ ppmv since 1850, or 70+ ppmv increase since 1960.
Even if humans are (near) 100% responsible for the CO2 increase, that doesn’t mean that the influence of the increase is huge or catastrophical. That is a complete different discussion. But in my opinion, skeptics do a disserve to their cause by insisting that there may be doubt of the origin of the increase, which is an item where the “mainstream” science is very strongly rooted in real observations…
Ferdinand Engelbeen says:
September 27, 2012 at 11:54 am
“Thus whatever the natural emissions and sinks are, were, or varied over the (far) past, over the past 50 years nature as a whole was a net sink for CO2. That is all we need to know.”
The thoroughly discredited “mass balance” argument rears its ugly head once again.
“Take a fountain where water is pumped from a bassin at the bottom and flows back into the bassin.”
Completely inappropriate analogy. This fountain has a drain, which removes water permanently. That water has to be replaced. The level in the fountain reaches an equilibrium level when the rate of inflow matches the outflow rate through the drain. Add an additional 3% of inflow, and the level increases… wait for it… 3%.
This is an active feedback system – the drain responds to the pressure in the water column above it, expanding and contracting in such a way as to attenuate changes in the level due to variation in the inflow. Static analogies are not even remotely applicable.
The temperature to CO2 rate of change relationship accounts for almost the entire change in CO2 in every detail. There is no possibility of significant human forcing.
Ferdinand and Bart:
I now again find myself in the middle between the two of you: Ferdinand is certain the recent atmospheric CO2 rise has a completely anthropogenic cause and Bart is equally certain the cause is completely natural.
Me? I don’t know the cause and I want to know it. So, I again withdraw in hope that the continuing argument between the two of you will tell me what I want to know.
Richard
E.M.Smith says:
September 26, 2012 at 8:47 pmGlobal cement production (a big CO2 producer) used / released 377 M tons of carbon as CO2 in 2007. Oh, the panic… Yet to consume that would take about 200 x 300 miles of high growth trees (at full production) for a year. Not enough to even notice if replanted in some of the strip mined clear cut areas of The Federal Forests…
Ummmm…no. The Forest Service (mismanages more than 200 MILLION acres of forest, almost all in the West), wouldn’t know how to spell the word, clear cut. Since we were lied to during the Clinton administration that the NW Forest Plan would make National Forest land management more rational and still produce a steady stream of timber = jobs + gobs of cash, the Forest Service and more recently the BLM as well, have mismanaged the timber lands under their care.
The example in Oregon is most egregious. Conservative estimate of growing stock = 700 BILLION bd ft, growing at a net annual rate of more than 11 BILLION bd ft. The current harvest on FS lands in OR = less than 100 million bd ft. There is a wall of wood out there, and the Forest Service is pi$$ing it away, and flushing jobs and cash to the counties along with it.
richardscourtney says:
September 27, 2012 at 1:23 pm
Oh no you don’t! I was taking a powder on this one letting you two slug it out. But, I can only take so many times of seeing that utterly ridiculous and silly “mass balance” argument regurgitated before my resolve weakens.
Please continue – I really don’t want to go through the whole futile exercise again.
Bart says:
September 27, 2012 at 1:08 pm
I was waiting for your reaction…
The thoroughly discredited “mass balance” argument rears its ugly head once again.
As long as there is no destruction of matter, the carbon mass balance must be obeyed at any moment either static or dynamic…
Completely inappropriate analogy. This fountain has a drain, which removes water permanently. That water has to be replaced. The level in the fountain reaches an equilibrium level when the rate of inflow matches the outflow rate through the drain. Add an additional 3% of inflow, and the level increases… wait for it… 3%.
The fountain has a drain: via the pump and back into the bassin. But let’s assume that the fountain has a natural supply from an unregulated underground well and has an overflow drain at the other side. The level in the bassin above the overflow drain then will be proportional to the supply, any supply. Now we add some more water from the drinking water network of the town via a hose, slowly increasing that extra supply and then we measure the increase in the bassin: that is in average about halve the extra supply over time with some variability also at about halve the extra supply. Thus the drain in average removes about halve the extra supply. How much of the observed increase then comes from the natural supply?
The temperature to CO2 rate of change relationship accounts for almost the entire change in CO2 in every detail. There is no possibility of significant human forcing.
There are clearly two separate processes at work: a high frequency process of 1-3 years and a process that has at least a period of 200 years, as the curvatory of the trend over the past 50 years is not even 1/4 of a period and the end is not in sight (not even after 160 years if you may believe the ice cores). So there is no reason to think that the same processes are involved and any resemblence of the same factor for fast and slow (temperature) processes is entirely spurious. That implies that the fast response to temperature is from fast processes (but limited in storage capacity) and the increase is from slower processes, but mostly from the human emissions, or you are violating about all known observations, while slower process are responsible for the removal of the bulk of the excess CO2 in the atmosphere.
Bart and Ferdinand:
Oh yes I do again withdraw from the debate about the cause of recent rise in atmospheric CO2. I have been through this time and again for about a decade.
There is insufficient data to resolve the issue and the mind-bendingly mistaken ‘mass balance argument’ only serves to pretend sufficient data exists.
For example, nobody knows the variability of CO2 output from volcanoes and the ‘mass balance’ attributes its effect on atmospheric CO2 to the anthropogenic emission!
The two of you can debate your different certainties and – in the unlikely event that one of you says something new – then I and others may learn from that.
Richard
Ferdinand,
What are your thoughts on the reports that coal seam fires emit some 2% – 3% of all CO2? These fires are unquenchable, and they have proliferated since the start of the industrial revolution. There are thousands of them now. Would they not have the same isotope signature of mined coal?
D Böehm says:
September 27, 2012 at 2:24 pm
What are your thoughts on the reports that coal seam fires emit some 2% – 3% of all CO2? These fires are unquenchable, and they have proliferated since the start of the industrial revolution. There are thousands of them now. Would they not have the same isotope signature of mined coal?
If these are the result of human intervention (started in coal mines?) they should be added to the human input. If they are natural (and probably much older than human intervention), they add to the natural input. These are rather difficult to classify things at the edge of natural and human. The same e.g. for wood: burning wood is classified as not adding to the human input, as most of the released CO2 was sequestered a few years to a few decades before from the atmosphere. But if you cut a lot of forest for agriculture it is added, because there is an unbalance in carbon sequestered. The same for historical things: burning 600 year old oak wood is not adding to the human input, but 600 year old peat is…
Anyway, the “fingerprint” in isotope signature is the same, if you or nature burns wood or coal. But the fine point of the oxygen balance shows the difference: Substracting the more certain oxygen use from inventories of fossil fuel burning from the measured oxygen use, shows a small deficit in decrease. Thus the whole biosphere, including uncertain low-13C sources like coal seams burning and natural forest fires is a net source of oxygen, thus a net sink for CO2 and preferably for 12CO2 and thus not the cause of the increase in the atmosphere neither of the 13C/12C ratio decline measured in the atmosphere.
richardscourtney says:
September 27, 2012 at 2:13 pm
For example, nobody knows the variability of CO2 output from volcanoes and the ‘mass balance’ attributes its effect on atmospheric CO2 to the anthropogenic emission!
All what the mass balance says is that no material can be destroyed or created from nothing.
In the case of the carbon balance: what goes in must reside there or must go out, but the total amount of carbon in all reservoirs can’t be different before or after the movements.
Humans add 8 GtC/year. We measure an increase in the atmosphere of 4 +/- 2 GtC/year. No matter how high or how variable the natural inputs were, the mass balance must be obeyed. That means that the natural outputs must be 4 +/- 2 GtC larger than the natural inputs.
Thus if the volcanoes increased their input from 10 GtC/year to 20 GtC/year from one year to the next year, that has no effect on the mass balance: either the CO2 levels in the atmosphere increased with 10 GtC extra or – which is the case – the measured increase stayed within the +/- 2 GtC natural variability and some other natural process sequestered (part of) the extra 10 GtC. In all cases, the human input was larger than the increase in the atmosphere, thus the only cause of the increase, because nature was a net sink for CO2…
@ferdinand meeus Engelbeen
The validity of isotope analysis to deferatiate natural/antro CO2 emissions presupposes that there aren’t any processes in the atmosphere that will alter the isotope balance over time. Like maybe cosmic rays for example.
Isn’t C14 supposed to be created in the atmosphere by cosmic ray bombardment? Can you rule out something similar for C13
D Böehm:
Your post at September 27, 2012 at 2:24 pm mentions CO2 emissions from coal seam fires. Such fires have always existed and so have natural methane leaks and oil seepages. The methane oxidises to CO2 and the oil is degraded by biota to eventually become CO2.
Variations in these natural CO2 sources are completely unknown and will probably remain unknowable.
In fact, almost everything about the carbon cycle is unknown or unquantifiable. And it is this ignorance which causes difficulty in having certainty about causation of the recent rise in atmospheric CO2 concentration.
Bart says his processing of the atmospheric CO2 and the global temperature time series demonstrates the rise is completely caused by temperature change. He may be right, but his analysis relies on assuming measurement accuracies which the data do not have.
Ferdinand says the unknown variations in natural sources and sinks can be ignored so the rise must be completely anthropogenic. He may be right, but his analysis relies on the improbable assumption that natural variations can be ignored.
The bottom line is that there is insufficient data to resolve the issue.
Richard
Ferdinand Engelbeen:
I am not returning to the debate but I write to point out to onlookers that your answer to me at September 27, 2012 at 3:17 pm demonstrates why I do not agree with your mass balance argument. I anticipate that you will dispute this post but I shall not respond to that because my sole purpose is to demonstrate our disagreement to others.
Your post begins saying
Of course it is true that, “the total amount of carbon in all reservoirs can’t be different before or after the movements”. But so what? At issue is why the carbon has changed in one specific reservoir; i.e. the atmosphere.
If a volcano increases its CO2 emission then the reservoir of the Earth’s magma reduces its carbon and the reservoir of the atmosphere increases its carbon. The only data one has about changes in reservoirs is the increase in the atmosphere, and that tells nothing about the reduction in the magma, so the mass balance assumes the increase is from the anthropogenic emission. The increase is NOT from the anthropogenic emission: it is from the magma!
And the same accounting error is true for any other variation in natural emission or sequestration when conducting the mass balance.
Richard
Richard,
As usual I agree with your comments. I don’t think I was explicit enough in my question to Ferdinand, though. To clarify, it seems reasonable that although there were always some coal seam fires before the industrial revolution, rising industry must surely have resulted in many more fires. Numerous fires in Appalachia were started during the past century, and almost all of them are still burning. Wherever there are coal fields there are underground coal fires.
We really do not know all the sources of CO2, or all the sinks for that matter, or all the ways in which they interact. But we do know that there is no discernable global harm or damage as a result of rising CO2. We also know that the biosphere has benefited from the rise in that harmless airborne fertilizer.
If and when someone is able to post measurable, testable evidence of global harm due to CO2, I will pay close attention. But there is no such evidence at present. Therefore, the principle of parsimony argues against adding the extraneous and unnecessary variable of CO2 to the discussion of global warming. Without any evidence to the contrary, it appears that the added CO2 is a net global benefit, with no apparent downside.
D Böehm:
Your post at September 27, 2012 at 4:09 pm says you agree with my argument, and I confirm that I agree with your argument concerning the benefit to the biosphere of increased atmospheric CO2.
However, I have an overarching position concerning the anthropogenic global warming (AGW) hypothesis. That hypothesis has three assumptions as its components; viz.
1.
The anthropogenic greenhouse gas (GHG) emissions, notably of carbon dioxide (CO2), are to some degree accumulating in the atmosphere.
2.
The anthropogenic GHG emissions are causing the observed recent rise in atmospheric GHG, notably CO2, concentrations whatever proportion of the emissions is accumulating in the atmosphere.
3.
The recent rise in atmospheric GHG, notably CO2, concentrations is significantly raising the global temperature.
There are reasons to doubt each of these three assumptions. I am a climate realist and, therefore, I accept whatever empirical data informs about these assumptions. Hence, I am certain that assumptions 1 and 3 are untrue because they are denied by empirical data. However, as I have repeatedly said in this thread, available empirical data is not sufficient to know if assumption 2 is true or not.
Importantly, if any one of the three assumptions is untrue then the AGW-hypothesis is falsified. And the hypothesis is doubly falsified because assumptions 1 and 3 are untrue. If assumption 2 were also known to be untrue then the entire AGW-hypothesis would be known to be wrong.
Richard
Ferdinand Engelbeen says:
September 27, 2012 at 1:50 pm
We’ve been through this all so many times before. Your arguments are invalid. They simply do not recognize the dynamic nature of the system, and how such systems are required to behave by physical and mathematical laws.
richardscourtney says:
September 27, 2012 at 3:28 pm
“…but his analysis relies on assuming measurement accuracies which the data do not have.”
Individually. But, instantaneous measurement accuracy only indirectly limits our ability to estimate the states of an ongoing process. Processing and filtering data, to dig down beneath the errors in measurement and divine the underlying content, is the entire raison d’etre of Estimation Theory. When you get overall agreement this good, it isn’t happenstance.
“””””…..ntesdorf says:
September 26, 2012 at 2:43 pm
It all reminds me of the Aristotlelian Science of epi-cycles where the failure of the theory to predict events was gradually modified with ever increasing complexity to keep up with reality. Rather than re-think the CAGW theory, counteractive mechanisms are added continuously to the model ib order to explain the failures. Eventually people notice that the theory is falling apart……”””””
So do tell; what is your theory of an earth centric solar system that DOES NOT include Epi-cycles.
Einstein tells us there is NO absolute frame of reference, so you can choose anyone you like. If you put the earth as the center of the solar system, then you end up with epicycles. And if you are stuck with ancient instrumentation, then fitting the pieces into such a system, would likely require periodic updates as better observations became available.
Gee, even today, GISS keeps updating climateTemperature observations that are barely 150 years old. So I would say that Aristotle did a pretty damn good job with his epicycles.
I once read a whole textbook, with charts, all about the solar system epicycles.
So is this a new take on the old problem?
It is not the carbon emissions that are causing AGW, it is the destruction of wetlands?
george e. smith,
Here is a great orrerry. You can set it for Copernican or Tychaen views; a sun-centered solar system, or earth-centered epicycles [a little hard to see the choices unless you put the cursor on them].