Guest Post by Willis Eschenbach
There’s an interesting measure of atmospheric CO2, called the “airborne fraction”. The airborne fraction is the fraction of the CO2 emitted each year which remains in the atmosphere. When humans emit say 9 gigatonnes of carbon, only about half of that remains in the air. The other half of the emitted carbon is absorbed, “sequestered” in some semi-permanent fashion, by various carbon sinks in the land and the ocean.
Dr. James Hansen of NASA, another in the long line of climate alarmists who don’t mind shafting the poor with expensive energy, has come out with a most surprising statement in his latest paper, Climate forcing growth rates: doubling down on our Faustian bargain, hereinafter Hansen 2012. The statement involves Hansen et al.’s explanation for a claimed recent decrease in the airborne fraction. Here’s their graphic showing the changes in the airborne fraction since 1960.
Figure 1. Hansen 2012 Figure 3. I’ve added a vertical line highlighting June 1991.
[ORIGINAL CAPTION] Fossil fuel CO2 emissions (left scale) and airborne fraction, i.e., the ratio of observed atmospheric CO2 increase to fossil fuel CO2 emissions. Final three points are 5-, 3- and 1-year means.
I do wish people would show the underlying data and not just averages, but setting that aside, here are the authors’ claims about the drop in the airborne fraction (blue line) post 2000:
We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks. One mechanism by which fossil fuel emissions increase carbon uptake is by fertilizing the biosphere via provision of nutrients essential for tissue building, especially nitrogen, which plays a critical role in controlling net primary productivity and is limited in many ecosystems (Gruber and Galloway 2008). Modeling (e.g., Thornton et al 2009) and field studies (Magnani et al 2007) confirm a major role of nitrogen deposition, working in concert with CO2 fertilization, in causing a large increase in net primary productivity of temperate and boreal forests.
This is an interesting argument, but it has a few moving parts. Let me list them.
1) Increased coal use leads to increased net primary productivity (NPP) .
2) Increased NPP is evidence of increased carbon absorption.
3) Increased carbon absorption leads to increased biologically driven carbon sequestration.
4) Increased biologically driven sequestration explains the post-2000 decrease in airborne fraction.
I’m good with claims number 1 and number 2, but from there they get increasingly unlikely for various reasons. I’ll go get the data and show the actual airborne fraction, but first, let me quote a bit more from Hansen 2012, this time regarding Pinatubo.
Remarkably, and we will argue importantly, the airborne fraction has declined since 2000 (figure 3) during a period without any large volcanic eruptions. The 7-year running mean of the airborne fraction had remained close to 60% up to 2000, except for the period affected by Pinatubo.
and also …
Thus we see the decreased CO2 airborne fraction since 2000 as sharing some of the same causes as the decreased airborne fraction after the Pinatubo eruption (figure 3).
I looked at the chart, and I looked at the dates. Pinatubo was in June of 1991. Here’s what I get from the data:
Figure 2. Annual airborne fraction (red line), along with 7-year average (blue). Green line shows theoretical airborne fraction assuming exponential decay of excess CO2.
So to start with, from both his graph and mine I’m saying absolutely no way to Hansen’s claim that there was a “decreased airborne fraction after the Pinatubo eruption”. Hansen seems obsessed with Pinatubo. He previously has claimed (falsely) that it represented a successful test of his GISS climate model. See here, here , and here for a discussion of how poorly the models actually did with Pinatubo.
He is now claiming (again falsely) that there is some drop in the airborne fraction after Pinatubo. I’m sorry, but that’s a totally false statement. There’s no sign of any unusual drop post-Pinatubo in this record at all, neither in the annual data nor in the average data. The majority of the drop he seems to be pointing to occurred well before Pinatubo occurred …
In passing, let me comment that any reviewer who let any of that Pinatubo nonsense past them should resign their commission. It was the first thing I noticed when I looked at the paper.
There’s a second problem with what Hansen et al. have done. They say regarding their 7-year average (blue line) that: Final three points are 5-, 3- and 1-year means. Sadly, this means that the final point in the 7-year average is forced to be equal to the last point in the raw data … easily the worst choice of ways to handle the final points of any average, almost guaranteed to have the largest error.
But that method does have one advantage in this case. It greatly exaggerates the amount of the recent drop. Note for example that had the data ended one year earlier, the final point in his average would have had a value 60% … here’s what the 7-year average figured their way would have looked like if the data had ended in 2010.
Figure 3. As in Figure 2, but with the 7-year average ending in 2010 using their method. Note that the final point is forced to equal the 2010 value.
As you can see, their curious treatment of the 7-year average at the end of the data is the only thing that makes the trend look so bad. When changing the data length by one year makes that kind of change in an average, you can assume that your results are far, far from robust.
But neither of those is the main problem with their claim. The main problem is that the general slight decrease in the airborne fraction is an expected result of the exponential decay of the excess atmospheric CO2. As the green line shows, the actual results are in no way different from the value we’d expect to see. The green line shows the result of the exponential decay of the excess CO2 if we assume a half-life of about 46 years. The expected value decreases slightly from 1970 to 2011.
It’s worth noting that if CO2 emissions leveled off entirely, the airborne fraction would gradually decay to zero. This is because if emissions level off, eventually the excess CO2 level will be such that the annual sequestration will equal the annual emission with nothing to remain airborne.
To close, let me return to their claim:
We suggest that the surge of fossil fuel use, mainly coal, since 2000 is a basic cause of the large increase of carbon uptake by the combined terrestrial and ocean carbon sinks.
I must confess that I hadn’t looked at fuel use by type in a while, so I was unaware of a large spike in coal use.
Figure 4. Carbon emissions by fuel type. Note the steady rise of natural gas, which will only increase with the advent of fracking.
So yes, coal use has indeed spiked since 2000, with a jump in coal emissions putting it back out in front of oil. I assume, although I’ve not checked, that this is the result of the huge increase in coal for electricity generation in India and China. And good on them, the folks in that part of the planet desperately need cheap energy.
Returning to the claims in Hansen 2012, it is true that the carbon uptake by the various sinks has constantly increased over time. This increase, however, appears to be much more related to the exponential decay of the CO2, and has less to do with the changes in the biosphere. We know this because the change in the amount sequestered is much larger than the change in the NPP.
Here are the figures. In 1960 the natural sinks were sequestering about 1 gigatonne of excess carbon annually. By 2011, this had risen to 4.5 gigatonnes annually. I agree that CO2 fertilization is real, but clearly this 4.5-fold increase in total tonnage of excess carbon sequestered cannot all be the result of increased NPP from CO2 fertilization.
So while I’m glad to hear that Hansen thinks that coal is good for something, I fear his explanation for the increase in the amount sequestered is not correct. The increases in the amount sequestered have been much, much larger (450% since 1960) than the increase in the amount of sequestration due to greater NPP.
Before I leave, let me remind folks what cheap electricity and energy from coal does for us all, rich and poor alike, every day of the year.
Figure 5. Daily output of coal energy. SOURCE
That huge benefit to the poor and the rich is what Hansen is trying to get rid of … but he and others have very little with which to replace it. So all that happens is that the price of energy goes up, and the poor once again are impoverished the most.
Brilliant plan, that fellow Hansen truly cares about the future … he just doesn’t seem to care if he hurts people in the present.
My best to everyone,
w.
Bernie Hutchins says:
March 29, 2013 at 8:32 pm
Good question, Bernie. In a piece I wrote a while ago but the !@ur momisugly#$%^ wouldn’t publish in the journals, I showed that for a given dataset it is fairly trivial to determine the resulting average error from a given method of handling the endpoints in a centered average. Then all you have to do is try the various methods, and pick the one that gives the lowest you know is the best of your known options for that dataset.
So yes, while there may not be a “good” choice, there is certainly an objectively determinable best choice for a given dataset.
Regards,
w.
Thornton et al 2009) and field studies (Magnani et al 2007) confirm a major role of nitrogen deposition, working in concert with CO2 fertilization, in causing a large increase in net primary productivity of temperate and boreal forests.
I thought that was the interesting part. After water, nitrogen availability is the biggest limiter of plant growth. Increase nitrogen availability and you increase biosphere productivity.
I hear today the USA has issued new vehicle emission rules that will substantially reduce nitrogen emissions (by converting nitrogen oxides to nitrogen).
This is part of an ongoing process since the 1970s of reducing emissions of nitrogen oxides. I have never seen any study calculating how much this affects biosphere productivity. The EPA and all the rest of the regulatory agencies tinkering with things they don’t understand the consequences of.
I’d add, N2O is 300 times more powerful a GHG than CO2. Add in the ozone depleting properties of nitrogen gases and you have a significant GHG potential as well.
TonyfromOz says:
March 29, 2013 at 8:53 pm
I agree, and they and the Indians are to be commended for their work in this area. I meant nothing derogative, and nothing beyond what I said—it is likely the post-2000 spike is mostly China and India.
All the best,
w.
AntonyIndia says:
March 29, 2013 at 8:09 pm
There appears to be a whole folder missing from the Columbia website. The link originally went to a folder on the website of Makiko Sato and James Hansen.
There is a document:
http://www.columbia.edu/~mhs119/EnergyConsump/
which shows a bit of it, China but not India. But the whole folder they reference has vanished, and as far as I can tell none of the documents in the folder is available anywhere on the web.
Go figure …
w.
No Stunad. CO2 is greening the planet.
The comment section in this article is priceless;
Sen. Inhofe ‘proud’ to be target of climate flick ‘Greedy Lying Bastards’
“Sen. James Inhofe (R-Okla.) sees criticism of him in a recent documentary about climate change as a badge of honor.
He’s among the targets in “Greedy Lying Bastards,” a recent film the claims to document fossil fuel industry-backed efforts to sow doubt about climate science and thwart emissions curbs.
“I was not surprised to see myself front and center on the promotional material for this climate-change movie, and quite frankly, I’m proud of it,” Inhofe told Tulsa World.
If the trailer is any indication, Inhofe appears repeatedly in the film. He’s also among the faces on one of the promotional posters, along with Exxon’s CEO and former Vice President Cheney.”
http://thehill.com/blogs/e2-wire/e2-wire/290961-inhofe-proud-to-be-target-in-climate-flick-greedy-lying-bastards
John –
A “true” moving average is generally understood to be non-recursive (FIR – Finite-Impulse-Response) AND Linear-Time-Invariant (LTI). In the case Willis mentions (dividing by 7, 5, 3, and eventually 1) the processing is not time-invariant (the “tap weights” are changing with time). In consequence, for example, any notion of “frequency response” loses it’s meaning. Your method is time-invariant but recursive. Nothing wrong with that – not-unlikely a better way here.
My concern is the notion of trying to exactly define a current value (energy if you will) while simultaneously exactly defining a time event (end of a time sequence). The “Uncertainty Relationship”, per Heisenberg, actually applies generally not just to quantum mechanics, but as a Fourier Transform property. Likely all it means here is that you can’t tell too much based on the last value(s). Willis pointed that fact out. Really this may be just saying that you actually DO need a LOT more data to speak of climate.
“The majority of the drop he seems to be pointing to occurred well before Pinatubo occurred …”
Willis,
I looked up, for the years 1990:1994,
CO2 growth ppmv 1.10 0.99 0.48 1.40 1.91
Total emissions Gton 6151 6239 6178 6172 6284
Airborne fraction: 0.395 0.350 0.171 0.501 0.671
There was a sharp drop in 1992, not sustained.
Willis says:
Because he can’t think of anything else?
Now, where are all those Warmists that said co2 is not plant food? Al Gore called it a pollutant. Here is that pollutant at work in a location near you.
http://youtu.be/P2qVNK6zFgE
I dont bother to read anything Hansen comes up with. The man has totally lost the plot and now lives in an Alice in Wonderland fantasy and the mad hatter’s world of logic.
Willis –
I would love to see your notes on treating endpoints and averaging. Is there a link somewhere?
Your comment really caught my attention as only 28 hours ago (although dated Mar 30) I posted a 24 page application note (AVERAGING – AND ENDPOINT GARBAGE) on my site. It is at:
http://electronotes.netfirms.com/AN395.pdf
Like you, I see that changing the length of the moving average enhances the error on multiple samples toward the end. I guess my main theme there was that engineers are likely good judges as to whether or not a time series corresponds to anything that is “real”. But when I suggest that engineers really should be running the world, I was told that “engineers don’t know anything – they just know how to make things work.” I am missing the insult here – somehow.
Bernie Hutchins
I wonder why they try so hard to make it complicated. Hansen needs to learn some basic chemistry and physical chemistry. The former tells us that stoichiometry determines how much carbon dioxide will be generated from a tonne of coal. The latter tells us how much photosynthesis will be affected by an increase in the partial pressure of carbon dioxide. Isn’t it ironic that Arrhenius determined much about the rates of chemical reactions? But then, I’m just a retired chemical engineer, what would I know?
It is important to note that during geologic times nature was able to remove over 3,500 ppm from the atmosphere. Does anyone know when the Earth is likely to see 1,000 ppm? My rough estimate certainly puts it well above 100 years and less than 220 years (based on last year’s annual rise). I am optimistic that humans will find (or have already found) reliable and abundant alternative energy sources by then. I am also optimistic about increased energy use efficiency through technology.
Hansen is getting closer, but is still hindered by overconfidence in a carbon cycle model with very large unknowns. And that’s just (his) known-unknowns that the IPCC also ignores.
To make progress, he needs to suspend his overconfidence in CO2-attribution based on the likely flawed treatment of isotope-ratios. They appear to take no account of NON-photosynthetic biochemical mediation of CO2 oceanic dissolution rates (coupled with temperature etcetera) and hence isotope ratios too. (Not that I believe they’ve got the photosynthesis sorted).
The oceanic diffusive boundary layer is populated with micro-organisms. Some even like to eat oil. Just because the human eye can’t see them, it doesn’t mean they aren’t going anything. This planet has had an ocean surface for quite a long time now. Those micro-organisms have accumulated a few fancy tricks.
Carbon dioxide diffusing across the bio-filmed atmospheric boundary layer into mildly alkaline sea water is hydrated and ionized to bicarbonate, which prevents it immediately diffusing back out again. This hydration step is actually much slower than a diffusion limited reaction. Which makes it not surprising that ~100% of all living species use the enzymatic catalyst carbonic-anhydrase to speed up the reaction by a factor of about ten million. We couldn’t get the CO2 out of our lungs quickly enough without it. To assert or pretend it has no effect at ocean surfaces strikes me as unlikely, to say the least.
When I look in the IPCC AR5 documents for answers to these kind of doubts, I discover pitiful phrases like
The only confidence I can draw from reading such statements of brazen ignorance, is that no organization celebrating such incompetence could be remotely capable of organizing a functioning conspiracy.
Of course it is greening the planet. The biosphere is carbon limited. Carbon is cash. It is the dollar in the biological economy. There are other currencies to be sure, but when cold catches Carbon… We conduct an inadvertent experiment. Near the peak of an interglacial we increase the money supply (I get closer to 5 than 3.5% but whatever).
Short term sequestration would be both biomass and carbonate. Biomass is a checking account, carbonate is burying it in the backyard. I don’t like to see the airborne fraction going down, it’s a bad economic indicator.
Mods, do I have a comment in the spam box ?
m.
[Reply: Not any more 😉 -ModE]
An “airborne fraction” where did that come from?
Thanks Willis. Hansen’s all over the place. I commented on his latest droolings on another blog (before your more reasoned analysis appeared) with the single word ‘Bizarre’. He seems to be revealing himself to be what he always was, an overeducated idiot.
It’s instructive to watch a scientific ‘consensus’ previously termed ‘robust’, ‘solid’ and even ‘settled’ now dissolving into a series of desperate excuses – Trenberth and his abyssal heat; Hansen and his aerosols and carbon sinks; climate sensitivity may be a tad less than we thought; clouds from all sides now, etc, etc.
Bizarro climate science RIP, 1988-201?.
” Hansen seems obsessed with Pinatubo. ”
Exaggerating the effects of volcanic emissions, esp. Mt P is the corner stone of exaggerated effects of CO2. The more volcanic emissions can rigged (model parameters) to produce an assumed cooling in late 20th c. , the more CO2 can be rigged (amplified by model parameters) .
This is why all GCMs, except the new Hadley model, quietly “announced” on Christmas eve, get post-1997 so badly wrong.
This game only works when you have enough volcanoes to keep up the pretence.
Well done for such a clear demonstration of how messy “runny” means can give totally false results.
NASA would not have got a man on the moon if they used running means in their calculations, yet it is rife in climate science. There is a large part of the “professional” climate science community that has not got beyond high-school level data processing. If they were not allowed to use running means and fit linear trends , they’d be lost as to where to start.
I would credit Hansen for explicitly saying what he did. Most just run their running means up to the end. where the window is half empty. and probably don’t even realise it’s not valid, or at best assume it “does really matter”. ( This what Pratt did in his AGU “poster” fiasco, it took a week of arguing before he even admitted he’s not done it correctly. )
“In a piece I wrote a while ago but the !@ur momisugly#$%^ wouldn’t publish in the journals, I showed that for a given dataset it is fairly trivial to determine the resulting average error from a given method of handling the endpoints in a centered average.”
Maybe you’d like to publish here ? I’d certainly be very interested see how to establish an error on something like that.
Are these the ones your looking for?
http://www.columbia.edu/~mhs119/Sensitivity+SL+CO2/
taken from this page
http://www.columbia.edu/~mhs119/
“I do wish people would show the underlying data and not just averages,”
An omission you also make 😉 Having gone to effort of finding the data to produce your figure 3, a data source link would be good.
Simple oversight I’m sure since you do link the source for the coal data.
TonyfromOz says:
“In fact the Chinese are actively working on ways to even further lower emissions by working towards Advanced USC.”
I disagree with what you say here Tony. I suspect the Chinese do NOT care about CO2 emissions and don’t buy into CAGW. Instead they are working towards Advanced USC because it is more efficient and thus you get more energy out of every ton of coal which potentially means lower cost overall!
Implying that the Chinese are more interested in lowering CO2 emissions than they are in getting the most energy out of each ton of coal is NOT substantiated in my opinion.
I wish the US would start building lots of these Advanced USCs as well. We really need cheap and abundant energy here in the US if we are to remain a leading world power and maintain a high standard of living. In addition, need to have a low cost alternative to natural gas to help keep prices low due to competition.
Jimbo says:
March 29, 2013 at 11:07 pm
It is important to note that during geologic times nature was able to remove over 3,500 ppm from the atmosphere…”
//////////////////////////////////////////////
The Paleo record is a real problem to the CAGW conjecture and tipping points.
During the times when Earth had high CO2 levels (possibly twice the level that you cite), it was often accompanied by warmth. That being the case, the warm oceans would have had a lesser capacity to act as a carbon sink. One major issues is how did the planet sequester these high levels of CO2? Precisely what were the sinks? It is probable that the oceans could only have begun to play a role in increasing the carbon sink, once ocean temperatures began to fall. Given the heat capacity of the oceans, it is likely, there would have been a significant lag before they themselves could have contributed towards the reduction of CO2 levels.
Willis:
Thankyou for this item which contains some important information. But you have accepted a dubious assumption which Hansen and others have introduced. That assumption distorts the entire discussion and provides severe doubt to its conclusions.
As bw says at March 29, 2013 at 8:05 pm, your entire discussion is based on adoption of an unfounded and very, very improbable IPCC assumption. You, Hansen and the IPCC say
NO! It is NOT.
The airborne fraction is the increase to atmospheric CO2 concentration which occurs in the air each year and is expressed as a proportion of the anthropogenic emission.
And you continue from that important mis-statement saying
NO! That is NOT true.
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 you and others assert. 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.
Nature does not know whether a CO2 molecule was emitted from an anthropogenic or ‘natural’ source.
So, on the average, ~3/156.5 = ~2% of all emissions accumulate each year.
This is important because you, Hansen and the IPCC frame the discussion on the basis that the human emission is known to be responsible for the recent rise in atmospheric CO2 concentration, but that is NOT known.
It is extremely unlikely that the 97% natural CO2 emission is mostly back and forth cycling which can be assumed to be constantly in balance. This improbable balance may exist, but nothing else in nature is observed to be so in balance and constant.
An imbalance of less than 2% p.a. between the natural emission and sequestration would account for all of the observed rise in atmospheric CO2. And there are several possible reasons why such an imbalance may have occurred.
One example of such a possible cause of natural altered imbalance is variation to undersea volcanism centuries in the past. Increased undersea volcanism would release additional sulphur ions which travel with the thermohaline circulation until they reach ocean surface layer centuries later. The increased sulphur in the ocean surface layer would reduce the pH of the layer with resulting alteration to the equilibrium concentrations of CO2 in the air and ocean surface layer.
A change of only 0.1 in ocean average pH (which is much, much too small for it to be measurable) would induce a rise in atmospheric CO2 concentration which is larger than has been observed in the past century. Hence, undersea volcanism could be the cause of ALL the observed rise to atmospheric CO2 concentration. And there are other possible causes, too.
Please note that the human emission of CO2 would not affect this in any way: the changed equilibrium would be the same whether or not the human emission existed.
The unfounded assumption that
is important. It assumes the natural emission and sequestration is constant and in balance.
This improbable assumption of balance between the natural inputs and outputs provides the conclusion that emissions from humans are causing the rise in atmospheric CO2 concentration. And that unfounded conclusion is distorting energy and economic policies around the world.
I don’t know if the rise in atmospheric CO2 concentration is entirely natural, or entirely anthropogenic, or partly natural and partly anthropogenic. But I want to know.
The myth that natural emissions and sequestrations of CO2 are known to be in a constant balance needs to be dispelled if we are to determine the true causes of the recent rise in atmospheric CO2 concentration and, thus, to avoid distortion of energy and economic policies.
Richard
[Bolding fixed – I hope as you intended ~mod]
The next big thing that would answer all of the chemical imbalance problems of the Earth would be a method to atomically remove a proton and a neutron from an atom of Calcium converting it to an atom of Phosphorus, and if the process could be done with ground lime stone as the basic input, the output would be energy, water, CO2, and the neutrons being absorbed producing the energy.
If the process were net exothermic, use it to generate steam to drive generators.