Dear Mr. Levitt,
The problem of global warming is so big that solving it will require creative thinking from many disciplines. Economists have much to contribute to this effort, particularly with regard to the question of how various means of putting a price on carbon emissions may alter human behavior. Some of the lines of thinking in your first book, Freakonomics, could well have had a bearing on this issue, if brought to bear on the carbon emissions problem. I have very much enjoyed and benefited from the growing collaborations between Geosciences and the Economics department here at the University of Chicago, and had hoped someday to have the pleasure of making your acquaintance. It is more in disappointment than anger that I am writing to you now.
I am addressing this to you rather than your journalist-coauthor because one has become all too accustomed to tendentious screeds from media personalities (think Glenn Beck) with a reckless disregard for the truth. However, if it has come to pass that we can’t expect the William B. Ogden Distinguished Service Professor (and Clark Medalist to boot) at a top-rated department of a respected university to think clearly and honestly with numbers, we are indeed in a sad way.
By now there have been many detailed dissections of everything that is wrong with the treatment of climate in Superfreakonomics , but what has been lost amidst all that extensive discussion is how really simple it would have been to get this stuff right. The problem wasn’t necessarily that you talked to the wrong experts or talked to too few of them. The problem was that you failed to do the most elementary thinking needed to see if what they were saying (or what you thought they were saying) in fact made any sense. If you were stupid, it wouldn’t be so bad to have messed up such elementary reasoning, but I don’t by any means think you are stupid. That makes the failure to do the thinking all the more disappointing. I will take Nathan Myhrvold’s claim about solar cells, which you quoted prominently in your book, as an example.
As quoted by you, Mr. Myhrvold claimed, in effect, that it was pointless to try to solve global warming by building solar cells, because they are black and absorb all the solar energy that hits them, but convert only some 12% to electricity while radiating the rest as heat, warming the planet. Now, maybe you were dazzled by Mr Myhrvold’s brilliance, but don’t we try to teach our students to think for themselves? Let’s go through the arithmetic step by step and see how it comes out. It’s not hard.
Let’s do the thought experiment of building a solar array to generate the entire world’s present electricity consumption, and see what the extra absorption of sunlight by the array does to climate. First we need to find the electricity consumption. Just do a Google search on “World electricity consumption” and here you are:
Now, that’s the total electric energy consumed during the year, and you can turn that into the rate of energy consumption (measured in Watts, just like the world was one big light bulb) by dividing kilowatt hours by the number of hours in a year, and multiplying by 1000 to convert kilowatts into watts. The answer is two trillion Watts, in round numbers. How much area of solar cells do you need to generate this? On average, about 200 Watts falls on each square meter of Earth’s surface, but you might preferentially put your cells in sunnier, clearer places, so let’s call it 250 Watts per square meter. With a 15% efficiency, which is middling for present technology the area you need is
or 53,333 square kilometers. That’s a square 231 kilometers on a side, or about the size of a single cell of a typical general circulation model grid box. If we put it on the globe, it looks like this:
So already you should be beginning to suspect that this is a pretty trivial part of the Earth’s surface, and maybe unlikely to have much of an effect on the overall absorbed sunlight. In fact, it’s only 0.01% of the Earth’s surface. The numbers I used to do this calculation can all be found in Wikipedia, or even in a good paperbound World Almanac.
But we should go further, and look at the actual amount of extra solar energy absorbed. As many reviewers of Superfreakonomics have noted, solar cells aren’t actually black, but that’s not the main issue. For the sake of argument, let’s just assume they absorb all the sunlight that falls on them. In my business, we call that “zero albedo” (i.e. zero reflectivity). As many commentators also noted, the albedo of real solar cells is no lower than materials like roofs that they are often placed on, so that solar cells don’t necessarily increase absorbed solar energy at all. Let’s ignore that, though. After all, you might want to put your solar cells in the desert, and you might try to cool the planet by painting your roof white. The albedo of desert sand can also be found easily by doing a Google search on “Albedo Sahara Desert,” for example. Here’s what you get:
So, let’s say that sand has a 50% albedo. That means that each square meter of black solar cell absorbs an extra 125 Watts that otherwise would have been reflected by the sand (i.e. 50% of the 250 Watts per square meter of sunlight). Multiplying by the area of solar cell, we get 6.66 trillion Watts.
That 6.66 trillion Watts is the “waste heat” that is a byproduct of generating electricity by using solar cells. All means of generating electricity involve waste heat, and fossil fuels are not an exception. A typical coal-fired power plant only is around 33% efficient, so you would need to release 6 trillion Watts of heat to burn the coal to make our 2 trillion Watts of electricity. That makes the waste heat of solar cells vs. coal basically a wash, and we could stop right there, but let’s continue our exercise in thinking with numbers anyway.
Wherever it comes from, waste heat is not usually taken into account in global climate calculations for the simple reason that it is utterly trivial in comparison to the heat trapped by the carbon dioxide that is released when you burn fossil fuels to supply energy. For example, that 6 trillion Watts of waste heat from coal burning would amount to only 0.012 Watts per square meter of the Earth’s surface. Without even thinking very hard, you can realize that this is a tiny number compared to the heat-trapping effect of CO2. As a general point of reference, the extra heat trapped by CO2 at the point where you’ve burned enough coal to double the atmospheric CO2 concentration is about 4 Watts per square meter of the Earth’s surface — over 300 times the effect of the waste heat.
The “4 Watts per square meter” statistic gives us an easy point of reference because it is available from any number of easily accessible sources, such as the IPCC Technical Summary or David Archer’s basic textbook that came out of our “Global Warming for Poets” core course. Another simple way to grasp the insignificance of the waste heat effect is to turn it into a temperature change using the standard climate sensitivity of 1 degree C of warming for each 2 Watts per square meter of heat added to the energy budget of the planet (this sensitivity factor also being readily available from sources like the ones I just pointed out). That gives us a warming of 0.006 degrees C for the waste heat from coal burning, and much less for the incremental heat from switching to solar cells. It doesn’t take a lot of thinking to realize that this is a trivial number compared to the magnitude of warming expected from a doubling of CO2.
With just a little more calculation, it’s possible to do a more precise and informative comparison. For coal-fired generation,each kilowatt-hour produced results in emissions of about a quarter kilogram of carbon into the atmosphere in the form of carbon dioxide. For our 16.83 trillion kilowatt-hours of electricity produced each year, we then would emit 4.2 trillion kilograms of carbon, i.e. 4.2 gigatonnes each year. Unlike energy, carbon dioxide accumulates in the atmosphere, and builds up year after year. It is only slowly removed by absorption into the ocean, over hundreds to thousands of years. After a hundred years, 420 gigatonnes will have been emitted, and if half that remains in the atmosphere (remember, rough estimates suffice to make the point here) the atmospheric stock of CO2 carbon will increase by 210 gigatonnes, or 30% of the pre-industrial atmospheric stock of about 700 gigatonnes of carbon. To get the heat trapped by CO2 from that amount of increase, we need to reach all the way back into middle-school math and use the awesome tool of logarithms; the number is
or 1.5 Watts per square meter. In other words, by the time a hundred years have passed, the heat trapped each year from the CO2 emitted by using coal instead of solar energy to produce electricity is 125 times the effect of the fossil fuel waste heat. And remember that the incremental waste heat from switching to solar cells is even smaller than the fossil fuel waste heat. What’s more, because each passing year sees more CO2 accumulate in the atmosphere, the heat trapping by CO2 continues to go up, while the effect of the waste heat from the fossil fuels or solar cells needed to produce a given amount of electricity stays fixed. Another way of putting it is that the climate effect from the waste heat produced by any kind of power plant is a one-off thing that you incur when you build the plant, whereas the warming effect of the CO2 produced by fossil fuel plants continues to accumulate year after year. The warming effect of the CO2 is a legacy that will continue for many centuries after the coal has run out and the ruins of the power plant are moldering away.
Note that you don’t actually have to wait a hundred years to see the benefit of switching to solar cells. The same arithmetic shows that even at the end of the very first year of operation, the CO2 emissions prevented by the solar array would have trapped 0.017 Watts per square meter if released into the atmosphere. So, at the end of the first year you already come out ahead even if you neglect the waste heat that would have been emitted by burning fossil fuels instead.
So, the bottom line here is that the heat-trapping effect of CO2 is the 800-pound gorilla in climate change. In comparison, waste heat is a trivial contribution to global warming whether the waste heat comes from solar cells or from fossil fuels. Moreover, the incremental waste heat from switching from coal to solar is an even more trivial number, even if you allow for some improvement in the efficiency of coal-fired power plants and ignore any possible improvements in the efficiency of solar cells. So: trivial,trivial trivial. Simple, isn’t it?
By the way, the issue of whether waste heat is an important factor in global warming is one of the questions most commonly asked by students who are first learning about energy budgets and climate change. So, there are no shortage of places where you can learn about this sort of thing. For example, a simple Google search on the words “Global Warming Waste Heat” turns up several pages of accurate references explaining the issue in elementary terms for beginners. Including this article from Wikipedia:
A more substantive (though in the end almost equally trivial) issue is the carbon emitted in the course of manufacturing solar cells, but that is not the matter at hand here. The point here is that really simple arithmetic, which you could not be bothered to do, would have been enough to tell you that the claim that the blackness of solar cells makes solar energy pointless is complete and utter nonsense. I don’t think you would have accepted such laziness and sloppiness in a term paper from one of your students, so why do you accept it from yourself? What does the failure to do such basic thinking with numbers say about the extent to which anything you write can be trusted? How do you think it reflects on the profession of economics when a member of that profession — somebody who that profession seems to esteem highly — publicly and noisily shows that he cannot be bothered to do simple arithmetic and elementary background reading? Not even for a subject of such paramount importance as global warming.
And it’s not as if the “black solar cell” gaffe was the only bit of academic malpractice in your book: among other things, the presentation of aerosol geoengineering as a harmless and cheap quick fix for global warming ignored a great deal of accessible and readily available material on the severe risks involved, as Gavin noted in his recent post. The fault here is not that you dared to advocate geoengineering as a solution. There is a broad spectrum of opinion among scientists about the amount of aerosol geoengineering research that is justified, but very few scientists think of it as anything but a desperate last-ditch attempt, or at best a strategy to be used in extreme moderation as part of a basket of strategies dominated by emissions reductions. You owed it to your readers to present a fair picture of the consequences of geoengineering, but chose not to do so.
May I suggest that if you should happen to need some friendly help next time you take on the topic of climate change, or would like to have a chat about why aerosol geoengineering might not be a cure-all, or just need a critical but informed opponent to bounce ideas off of, you don’t have to go very far. For example…
But given the way Superfreakonomics mangled Ken Caldeira’s rather nuanced views on geoengineering, let’s keep it off the record, eh?
Your colleague,
Raymond T. Pierrehumbert
Louis Block Professor in the Geophysical Sciences
The University of Chicago
Hi Mark,
We’ve been to seven different vendors, all world wide suppliers.
Because of the way they price the turbines they are all within 5% of each other.
We were hoping for a reduction in price due to the economic downturn,
turned out to be fairly minimal. One could get lower prices if you wanted to
take immediate delivery which was not possible for our project.
Turbines produced today are quite the impressive machines and are approaching the
theoretical maximum efficiency in terms of translating wind power to electrical power.
Most of the ongoing development is in larger machines and improving the reliability
of things like the gearbox. Of course, larger machines means more noise so siting can
become a challenge.
Thanks for your input.
PHG, California seems to be able to do better than you’re getting. Someone somewhere is able to repeat that.
PS you’re welcome.
“California seems to be able to do better than you’re getting. Someone somewhere is able to repeat that.”
cite plz
If only we could get actual installation quotes for solar/wind based on your beliefs/google searches. Do you have any vendors to recommend? If I can get a quote that shows a 10%+ IRR on 7 years or less for solar panels at my shopping centers, I’ll pay you the commission! Send info to my business address at ss1@rblre.com.
Here’s a real deflater to geo-engineering hopes, including possibly biochar (which I’ve been touting lately):
Geo-Engineering and Biochar: White Roofs, Black Dust and Slippery Slopes, http://www.climateark.org/blog/2009/06/release-geo-engineering-and-bi.asp#more
Philip (#484) said:
I think you missed something. With coal power, the extra heat to the atmosphere is calculated as all the energy in the coal burned, which already includes the 33% that is turned into electricity. With the solar cells, the extra heat to the atmosphere is calculated as the solar energy absorbed by the cells less the solar energy that would otherwise have been absorbed by the surface; the energy absorbed by the cells already includes the 15% that is turned into electricity. Since Raypierre in both cases includes the energy that is converted into electricity, he is in both cases counting all this energy as waste heat, isn’t he?
Mark, in 480 wants to know more about biochar.
Credit for discovering the benefits of biochar in the soil generally
goes to long lost Amazonians with their terra-preta soils. These soils
were found to be much more productive than surrounding soils, and the
difference was the addition of charcoal.
http://terrapreta.bioenergylists.org/ for more.
It works because the char has surface area in the range of 500 square
meters per gram. The surface area and the variety of pore sizes
adsorbs nutrients and provides an environment for the soil biota that
fix nutrients. It also helps store water; it’s somewhat more effective
at that than ordinary organic matter.
A few sites where you can start learning more:
http://groups.google.com/group/pnw-biochar-meeting-may-21-22-presentations/web/pnnl-presentations-with-descriptions?hl=en
http://www.biochar.info/
http://www.agnet.org/library/eb/430/
http://climatelab.org/index.php?title=Biochar
Thanks Ray for posting this educational rebuttal.
I do not think I am alone in holding the University of Chicago to a higher standard than just about any other educational institution, so it was particularly troubling to see a distinguished professor, even if only in Economics, apparently unable able to do sums.
-m
“…by your argument that all electricity eventually ends up as waste heat…”
Someone really said that? I guess yeah, if you’re talking about theoretical physics and the lifetime of the entire universe as a closed system, sure entropy wins. But realistically, in our little sliver of existence, no. If I use electricity to move a 20 ton bullet train across 100 miles, electricity was used to move mass, not generate waste heat. Same goes for burning coal in a steam locomotive – energy in the coal is being used to move mass. Extrapolate to gasoline moving all these cars around. I believe that’s called converting chemical energy to mechanical energy, or somethin’ like that.
[Response: Just think it through. What happened to all that kinetic energy? – gavin]
“Here’s a real deflater to geo-engineering hopes…”
Liked the article, Lynn. It takes a crafty politician to turn geo-engineering into an ominous boogieman. Of course they use the good old “slippery slope” argument – white roadways first, and next we’re… what? Only God knows! My only concern is that my wife would end up blind because she’d be staring at a white road every day on her 45 minute commute.
488 BPL
FWIW, global annual sediment flux into the ocean from all rivers is estimated at 25 GTon/yr.
Mark says:
“I now doubt that you are legitimate and are instead masquerading as a “moderate” in order to keep the doubt alive. “at least on this site” has killed your reputation as a thinking moderate.
Don’t say things to people you wouldn’t say to their face Mark. Especially assinine things like this that essentially prove John’s point about broad brush characterizations.
Gavin (inline at #508, 6 November 2009 @ 5:07 PM):
Hey, we really made out on the kinetic energy of Voyager. Say…this suggests a geo-engineering project just as reasonable as SO2, white roads and biochar that would also boost NASA’s budget and employ thousands. Someone should do the calculations.
Steve
“Just think it through. What happened to all that kinetic energy?”
It was used to do work. Work = F x d, right? Sure, you can equate that to “heat” on paper, but it’s not the kind of heat that goes into making the system’s temperature increase (thermal energy). Let’s consider the other portion of the mechanical energy equation – potential energy. If I drive the car up a mountain and park it at the top, I’ve converted chemical energy in the gasoline to potential energy, and as long as the car sits up on that mountain the potential energy isn’t going anywhere. Same principle applies if I use an engine to pull a buoyant sphere to the bottom of the ocean and attach it to a hook. As long as the that buoyant sphere is at the bottom of the ocean, that potential energy is locked down.
Actually, I like that as a geoengineering solution. Everyone, please attach a trailer to your vehicle, fill it up with as much mass as it will haul, drive it to the top of the nearest mountain, park it there and walk away. Carbon energy sequestered – Nobel Prize please!
Mark (480) wrote:
“Do you have anything on how carbon sequestered in the active upper layer of the soil can both exist for centuries (though my previous interlocutor on this said thousands of years) AND manage to actively participate in the health of the soil at the same time?”
Chapter 6 in Biochar for Environmental Management Science and Technology Lehmann, Joseph (2009)
http://books.google.com/books?hl=en&lr=&id=w-CUty_JIfcC&oi=fnd&pg=PT117&dq=biochar+biota+substrate&ots=clh0GWVXB3&sig=TDdagWCnHWam4Po-SI1G2WdjBlQ#v=onepage&q=biochar%20biota%20substrate&f=false
I can’t help but wonder why reasonable people bother responding to Mark. He sometimes hits on-target, and in those instances, good for him. Probably 50% or more of the time, he makes various bizarre misreadings of content or intent, and he becomes increasingly aggressive, irritating and off-topic when these errors are pointed out to him. It seems to me that the only sensible way to deal with this behavior (so long as it isn’t moderated out) is to ignore him, and I would strongly recommend this to others tempted to engage with him in any argumentative context.
In shorter form: don’t feed the troll.
I stumbled across this interview with Graeme Pearman, an ex-CSIRO climate scientist – main expertise is on atmospheric science. It is worth a read as it discusses the psychological issues behind getting action to happen; indeed, Graeme Pearman has moved into researching the psychological aspects of decision making etc.
Steve (#512, 6 November 2009 @ 6:54 PM):
You say- “If I use electricity to move a 20 ton bullet train across 100 miles, electricity was used to move mass, not generate waste heat.”
I am not a physicist, but I do know that your train emitted heat for 100 miles to maintain speed against friction (which results in heat), and the remaining kinetic energy is turned into heat when it stopped. Otherwise, where did the energy go? This is pretty basic.
Steve
Steve, 512: You’re losing your energy balance. You have a toy train, sitting still. You push it forwards, applying a force, and it starts moving. You let it go. In the absence of friction or drag, it’ll go forever at the same velocity. F = ma. If F = 0, then velocity does not change.
But that doesn’t happen. The kinetic energy of the train would be lost over time, as friction and drag forces slow it down. The kinetic energy is lost to heat at the rails and the surface of the train. You have to push the train again to keep it moving.
So yes, the energy being put into the train is being lost continuously as heat, in a very real way. I agree with Gavin – if you follow through on what where your electricity is going, it’s eventually going to be lost as heat, somewhere.
Re 512 Steve – additional to 516 Steve Fish and 517 tharanga – of course, if you move all your trains uphill, there will be some potential energy stored – likely less than the energy input because of friction. A similar logic applies to regenerative breaking – you might not lose the energy to heat when you stop. But if this pattern continues indefinitely, eventually you’ll have all your trains on the top of Mount Everest, etc. What happens when you want to bring the trains back to complete the loops? If the energy didn’t end up as heat than it ends up in useful form and thus replaces energy input. Almost all energy input must at some point be to balance loss, since over time net storage is small (when metal doesn’t oxydize, it reduces the need to create more chemical energy by reducing oxydized metal).
Okay, maybe not all loss is heat. Radio waves are lost to space. You brought up a space probe – nice example. Some light energy is also lost to space as light. These are relatively small amounts, though.
(And of course, attempting to cool the Earth by increasing waste of light would be … well, wasteful, and likely occur with greater heating to supply the greater electricity, unless it is from hydroelectric or wind, etc…)
“If the energy didn’t end up as heat than it ends up in useful form and thus replaces energy input.”
Clarification – some useful energy is not used, but such energy tends to end up as heat (as it is not attended to – there is no incentive to stop if from increasing in entropy if it is not going to be used for a non-thermal purpose).
Clarification – “there is no incentive to stop if from increasing in entropy if it is not going to be used for a non-thermal purpose” … AT a lower temperature than it was.
Steve (#512),
I has a fascination as a child with trains and their rails. In the Winter, just after a long train had passed, one could melt snow very quickly on the rails which were heated by the train’s passage. All of the engine’s power in a train moving along at constant speed on the flat is going into heating those rails and wheel bearings and pushing air out of the way. Each vortex of displaced air eventually dissipates as random motions of molecules moving a little faster than they used to (at higher temperature). All the sound transmitted down the rail that lets you know the train is coming also ends up heating the rail. The jingle, and the rumble, and the roar in the air heats the air. It all turns to heat because you can’t destroy energy. It has to persist and heat is its final form.
Now, you can use electricity, for example, to boost the chemical potential of oxidized silicon or aluminum to make a solar panel or a soda can. But that is just heat delayed since that stuff will oxidize again eventually, releasing heat as it does so. You can build buildings and have potential energy stored in the roof, but that is going to tumble down eventually and the energy will be dissipated as heat. As I said earlier in the thread, really only light and radio waves are able to escape and not heat the environment.
Pierrehumbert’s criticism of Levitt & Dubner’s solar panel analysis seems right. This though was a very minor part of their pitch. The major part concerned albedo geoengineering, whose harmlessness Pierrehumbert complains they presented as being settled.
Perhaps he missed mention on p199 of how Myhrvold, who is “quick to deny that he dismisses global warming itself”, is not “arguing for an immediate deployment of Budyko’s Blanket – but, rather, that technologies like it be researched and tested so they are ready to use if the worst climate predictions were to come true”.
“Don’t say things to people you wouldn’t say to their face Mark”
I don’t Jim.
Stop putting thoughts into other people’s heads that are actually in yours.
David in 506: “Credit for discovering the benefits of biochar in the soil generally
goes to long lost Amazonians with their terra-preta soils.”
No, I want to know about how carbon improves the soil without becoming part of the carbon cycle.
I know that char can improve the soil. I’ve got a garden myself.
But the statement is that biochar can exist unchanged for centuries.
The link I’ve been given earlier doesn’t show it:
http://books.google.com/books?hl=en&lr=&id=w-CUty_JIfcC&oi=fnd&pg=PT117&dq=biochar+biota+substrate&ots=clh0GWVXB3&sig=TDdagWCnHWam4Po-SI1G2WdjBlQ#v=onepage&q=biochar biota substrate&f=false
It turns up that char is helpful but there’s this bit in it:
“Where sufficient O2 is available, aerobic respiration will be the dominant metabolic pathway for energy generation, resulting in water (H2O) and CO2 as the primary metabolic products.
So please don’t insult my intelligence and make up what you’d like to answer. Give me the answer I ask for.
Where is the proofs of biochar in the soil both increasing its fecundity AND lasting without significant inclusion in the carbon cycle (which we are trying to remove CO2 from) and lasts for centuries.
Not the question you seem to want to answer “Where is the proofs of biochar in the soil increasing its fecundity”.
Answer the whole question.
““California seems to be able to do better than you’re getting. Someone somewhere is able to repeat that.”
cite plz”
FFS Steve, it’s in the freaking previous pages.
OK, for the hard of thinking, here you go Steve:
http://en.wikipedia.org/wiki/Wind_power#Growth_and_cost_trends
http://www.facebook.com/note.php?note_id=75824186023
http://www.sourcewatch.org/index.php?title=Comparative_electrical_generation_costs
http://en.wikipedia.org/wiki/Wind_power#Growth_and_cost_trends
All have been given before.
Heck, the Danes pay less than $2500 per kW for turbines. Australia doesn’t pay that much.
Someone is gypping PHG. Probably by spinning “Oh, it’s so risky to have a new style of power source so we need a 2 year ROI rather than 10 that you get from coal…”.
A thought if I may.
Even if I mayn’t.
I’ve asked before for any evidence or explication of this “mark is just mean” meme. None has been forthcoming but I HAVE recieved even more mealey-mothed “mark’s just mean” comments again.
It seems to me this meme is as strongly held and as unwarranted as the meme “CO2 lags temperature therefore AGW is false”. Both are immune to any counterintications and seemingly to the idea that any form of proof other than statement again and again is necessary.
And truly, hands up ANYONE who can say “CO2 never lags temperature”. Therefore isn’t there evidence of that meme “CO2 lags temperature” is actually true?
But why is it false?
Consider why. Then transpose.
Oh, and Jim B, any evidence or explanation of how you make this assertion “assinine things like this ” in #510 or do you just prefer being rude to people?
PHG: “Turbines produced today are quite the impressive machines and are approaching the
theoretical maximum efficiency in terms of translating wind power to electrical power.”
There’s actually a heck of a lot to be done making turbines that respond better to low wind conditions.
There’s a lot of work to make them fit in new niches (e.g. ducted turbines in city streets, to annul the wind farm problem of distance from energy source to energy sink).
The reason why prices didn’t drop is because wind power is cheap and demand for turbines still outstrips demand. And, being a free-market commodity, you see price increases.
After all, this is what you do with the energy output, isn’t it.
still outstrips supply…
Grrk.
Mark #523 said “No, I want to know about how carbon improves the soil without becoming part of the carbon cycle.”
I believe that David in #506 has already given at least three reasons for how it improves the soil and none involve metabolism of the charcoal.
“It works because the char has surface area in the range of 500 square
meters per gram. The surface area and the variety of pore sizes
adsorbs nutrients and provides an environment for the soil biota that
fix nutrients. It also helps store water; it’s somewhat more effective
at that than ordinary organic matter.”
And as for the turnover of charcoal in soil. Charcoal is almost pure inorganic carbon. There is no biological process which can metabolize inorganic carbon. The only ways of losing it from the soil has to involve non-biological physical or chemical processes.
“The jingle, and the rumble, and the roar …”
Okay, a physicist knows the lyrics to the Wabash Cannoball?
Try Google Scholar; it’s still being debated how the carbon levels became so increased in those soils. Eliminate ‘biochar’ from the search and you see a different set of possible answers; it’s always worth modifying searches.
http://scholar.google.com/scholar?hl=en&q=dating+carbon+amazon+preta+-biochar&as_ylo=2007
For example:
The material may be soot accumulated inside buildings from cooking fires, rather than charcoal:
http://www.arch.cam.ac.uk/~maa27/Arroyo-Kalin2007_4974_ms.pdf
“… However, in settlement soils charcoal is concentrated abundantly in the very fine silt to clay sized fraction. This is a size fraction that can be associated with soot particles. How does this concentrate so significantly? There are probably a few ways but I would submit here that an important one we need to envision is a scenario where lightweight particles are buried easily rather than being displaced by human action, rainwater or wind. What is this scenario? Ethnoarchaeological studies, notably Zeidler and Stahl’s work with Achuar house in lowland Ecuador, strongly suggest that abundant ash, charcoal and small fraction bone are accumulated inside walled and roofed structures with earthen-floors, that is inside houses [41, 42]”
Andrew’s recollection is correct, he’s right that historically char was believed to be that way, but some recent research suggests most char isn’t almost pure inorganic carbon:
http://www.springerlink.com/content/e501h8h77224w674/
“… Considering results reported in the pyrolysis literature in combination with those obtained from controlled charring of plant material and soil organic matter (SOM), it has become clear that common models claiming char as a graphite-like material composed mainly of highly condensed polyaromatic clusters may be oversimplified.”
You know the point I’m trying in my stolid, plodding, boring fashion, to make here — the above are only examples.
Mark says (482), “If you insist you have an opinion despite knowing nothing, then that’s denialism again.”
Here’s an interesting qualifier: what’s a person called who has no scientific knowledge of climatology but whose opinion is solidly supportive of AGW? A “denier,” I suppose…
Mark does highlight an important point in there. You can only deploy wind and solar as quickly as these units can be produced, and both are exposed to swings in materials costs, just as anything else is.
A look at charts of silicon prices tells the story pretty well: silicon production was geared around the computer industry; with a surge in demand for solar, demand for silicon quickly exceeded supply and prices soared. The silicon supply will adjust to the increased demand over time, but it doesn’t happen overnight. This may give thin-film solar cells an advantage over traditional PV cells, as they will hopefully use less silicon per unit energy produced.
Mark, the part you are missing from the story is subsidies. Germany subsidises solar at a remarkable rate, and US wind investment follows something of a boom-and-bust cycle as subsidies lapse and then are renewed. I’m not saying subsidies are bad, but you can’t take a subsidised price and then say it’s inherently cheap. And yes, in some applications and areas, wind could well be competitive with fossil fuels, even without subsidy, but that doesn’t mean this is generally true for all users. Finally, it takes a bit of hubris to find very rough calculations on facebook which obviously aren’t equal comparisons nor appropriate cash flow calculations, and think that overrides the experience of people who are actually active in this market and build the things.
Re: #514, which reads
” It seems to me that the only sensible way to deal with this behavior (so long as it isn’t moderated out) is to ignore him, and I would strongly recommend this to others tempted to engage with him in any argumentative context.”
That would take all the fun out of it!
Re the discussion started by Mark’s question “Do you have anything on how carbon sequestered in the active upper layer of the soil can both exist for centuries (though my previous interlocutor on this said thousands of years) AND manage to actively participate in the health of the soil at the same time?”
Science 9 August 2002: Vol. 297. no. 5583, pp. 920 – 923 DOI: 10.1126/science.297.5583.920
The Real Dirt on Rainforest Fertility, Charles C. Mann
“A rich, black soil known locally as terra preta do Indio (Indian dark earth), it sustained large settlements on these lands for 2 millennia…”
“As a rule, terra preta has more “plant-available” phosphorus, calcium, sulfur, and nitrogen than surrounding oxisols; it also has much more organic matter, retains moisture and nutrients better, and is not rapidly exhausted by agricultural use when managed well.
The key to terra preta’s long-term fertility, Glaser says, is charcoal: Terra preta contains up to 70 times as much as adjacent oxisols. “The charcoal prevents organic matter from being rapidly mineralized,” Glaser says. “Over time, it partly oxidizes, which keeps providing sites for nutrients to bind to.” But simply mixing charcoal into the ground is not enough to create terra preta. Because charcoal contains few nutrients, Glaser says, “high nutrient inputs via excrement and waste such as turtle, fish, and animal bones were necessary.” Special soil microorganisms are also likely to play a role in its persistent fertility, in the view of Janice Thies, a soil ecologist who is part of a Cornell University team studying terra preta. “There are indications that microbial biomass is higher in terra preta,” she says, which raises the possibility that scientists might be able to create a “package” of charcoal, nutrients, and microfauna that could be used to transform oxisols into terra preta.”
According to http://www.jstor.org/pss/280517, the soils were seen to be widely distributed in the 1960’s and many studies (Sombrock-1966, Ranzani et al-1970, Vieira et al-1971, Smith-1980) indicated “anthropic origin”.
“Amazonian dark earths: explorations in space and time,” Bruno Glaser, William I. Woods (partly accessible through google books), shows carbon dating ages older than 1290+-30 years for all samples, up to 2k years, for one site studied. The clustering of dates indicated that most of the production of terra preta took place over a period of a few hundred years.
“Biochar for Environmental Management: Science and Technology” By Johannes Lehmann, Stephen Joseph (also in google books) states that some terra preta charcoal has been dated to 7k years old.
A lot of info on carbon in soil – “THE ORGANIC GEOCHEMISTRY OF CHARCOAL BLACK CARBON IN THE SOILS OF THE UNIVERSITY OF MICHIGAN BIOLOGICAL STATION”, William Hockaday Phd Dissertation
http://www.ohiolink.edu/etd/send-pdf.cgi/Hockaday%20William%20C.pdf?acc_num=osu1141850676
“Additionally, the polar surface functionality such as the carboxylic acid groups giving rise to the sharp peak at 172 ppm in the 13C NMR spectrum of the aged charcoal, may act in a manner similar to activated charcoal, chelating growth limiting minerals and polar organics, preventing them from leaching out of the soil. In any case, the fact that these soil charcoal particles are heavily colonized by filamentous microorganisms provides new insight to the role of charcoal in soil ecology, and another mechanism (in addition to cation exchange) to consider as an explanation of the fertility enhancement observed in charcoal amended soils (Glaser et al., 2000).
“Radiocarbon dating of BC in deep ocean sediments shows that there is a period of several thousand years (2,400-13,900yrs) between the production of BC and its eventual deposition to open ocean sediment (Masiello and Druffel, 1998).”
“…the data presented here show that a labile fraction of charcoal BC is chemically degraded in forest soil on a timescale of 100 years, and exported to a more transient DOC pool.”
So, some fraction of biochar is long lived, some fraction enters into the biochemical cycle in 100 years. What fraction goes where and how long it takes depends on what the source material is(woodchips, grass, sewage sludge, olive pits), the parameters of the production process(rate of heating, maximum temperature, duration of high temperature exposure, N2/O2/H2O flow rates; too many leftover volatiles can make biochar toxic to plants), and the environment where it is placed (soil type & pH, rainfall, temperature, crops & cropping system). There is a lot of research being done, and it so far looks promising for being a win, win, win process – sequesters carbon, can provide carbon neutral bioenergy from the volatile fraction, and can be used to better deal with waste currently dumped in landfills to generate methane.
Biochar part 2
I left out another promising “win” – benefits to agriculture.
As a geoengineering solution, it is attractive because we already know it works, at least on the engineering end.
Some unanswered questions are:
can it be scaled up to the “geo” level? (probably)
how can it be made as safe and effective as possible? (process control-a stone age culture with limited knowledge made it work; even if we aren’t any better at the “how”, we’ll have a better handle on the “why”)
what are the economics involved? (The value to agriculture and waste disposal alone may support starting small in niche markets, and gathering a lot of useful process control data. Since we don’t know how much AGW could cost, and don’t want to find out the hard way that it’s “too much”, the value of biochar carbon sequestration would have to rely on an insurance model – you don’t know how much burning down your house would cost, but you pay for insurance anyway)
Converting a reasonable fraction of Net Primary Production of the biosphere to biochar could draw down a large fraction of the CO2 currently emitted and sequester it for a significant number of years at a manageable cost; it won’t be a magic cure that will solve all our problems and allow BAU.
No doubt the policy spinmeisters and potential profiteers will argue about the meaning of “reasonable” “large fraction” “significant” “manageable” and just what is the probability of “won’t”. People whose knee jerk reaction that anything that might benefit the environment is that it must be just another hippy liberal watermelon(green on the outside, commie pinko on the inside) soc – ialist plot to take away their right to mix beer cans, glass bottles, junk mail, styrofoam fast food containers, food waste, and the odd lot of brass shell casings from the firing range/back deck in THEIR trash will argue “You scientists don’t know X to enough decimal places to prove it to me, and even though I’m not real sure what a decimal place is, or what ‘it’ is you want to prove, I still get to decide.”
Andrew Hobbs (530) — The standard claim for biochar at no more than root depth (in temperate zones) is that about 1/2 of the biochar re-eneters the active carbon cycle within a few decaedes. The remainder persists, it is stated, for many centuries. I don’t know how or why the former occurs, but decadal long experiments demonstate that it does.
526 Mark asks “for any evidence or explication of this “mark is just mean” meme. ”
Mark, how about your track record for [edited] comments? I suppose you could be saying cheery things that happen to get [edited], but most folks just assume they’re insulting.
“All of the engine’s power in a train moving along at constant speed on the flat is going into heating those rails and wheel bearings and pushing air out of the way.”
If it were, the train wouldn’t be moving – it would be sitting still.
“and the remaining kinetic energy is turned into heat when it stopped.”
That’s why I asked what if the vehicle is going uphill and stops? The kinetic energy goes into potential energy (basic physics).
Here’s your experiment:
Drive your train on tracks cross-country, all flats. Drive it till you’re out of coal. Don’t break – we all know it will eventually stop due to friction. Drive the same train along the same tracks, but tilted at a 45 degree angle. Drive it till you’re out of coal. Don’t break… you notice it stops! Turns out, the track was one of them fancy roller coaster tracks, so your train can go one direction but not the other. For both trains, mind you – we gotta have control over our variables!
One of these systems has coal energy “locked in”, the other doesn’t. How?
It’s the same principle behind the “locking in” of solar energy within the atomic bonds of the coal. Otherwise, why are we getting so bothered about igniting all the world’s fossil fuels in the first place? Yes, all the heat eventually escapes, from everything. But what we’re concerned about is the when and the where of it. Specifically, not all so fast while we’re around.
Nature takes a spectacular nano-machine it’s built called a Seed, and heats it. The seed organizes, builds, gathers. It creates an island of order in a sea of disorder. As long as some of that order remains, there is potential. Fossil fuels are the ghosts of many Seeds. As long as we don’t crack them open, Nature’s potential remains locked inside.
We are of Nature, and in a sense Seeds. We organize, build, gather – build islands of our own. Look around you. All of that order in the things we’ve built is an increase in entropy, and as long as it remains the potential is locked inside. If we cracked open some coal to make what you’re looking at, then some of that coal’s potential is locked inside, still – we transferred it’s entropy. And it isn’t getting out until it returns to the original state that us Seeds found it in.
So yes, all of the energy of the fossil fuels that have been burned to date will, eventually, be spread continuously and homogeneously throughout the biosphere. You could describe it in terms of an increase in thermal energy, if that’s your fancy. But for that to happen, everything that’s been built with those fossil fuels must return to it’s original state of disorder. We still have canyons upon canyons full of garbage – it’s got a waise to go.
Entropy – look it up if you don’t believe me.
Oops, sorry. Order is a decrease in entropy. Entropy is chaos. I got screwed up by Wiki’s “entropy is the potential for disorder”.
Mark, look up http://www.re-char.com to find out how biochar helps the soil, increasing productivity by 20% AND sequestering carbon for a long time….
re 540 Steve,
You quote: “All of the engine’s power in a train moving along at constant speed on the flat is going into heating those rails and wheel bearings and pushing air out of the way.”
Are you trying to create confusion by changing the stated premises that the train is moving at a constant speed and on the flat?
If you want to change the experiment to include energy needed to accelerate and go up hill, that would be a different experiment.
Looking up entropy in my handy old freshman physics book by Sears (Addison Wesley 1950), I find I am reading about the Second Law of Thermodynamics which Sears says “is the law of entropy.” Sears candidly says, “There is no concept in the whole field of physics which is more difficult to understand than is the concept of entropy, nor is there one which is more fundamental.”
So I doubt if we will get the concept of entropy thoroughly digested on these comment pages.
Now that I have the book open I note Sears also says regarding First and Second Laws of Thermodynamics, ” –every process that takes place in Nature,— must proceed in conformity with these two laws.” I rely on this to assert that wind and solar power are under this legal jurisdiction, contrary to some assertions. (Nature of course includes an important source like the sun which I will allow that we on earth can count as free of charge.)
That being said, I leafed back to the beginning of the chapter to find an explicit statement in this, an established reference, that states that “chemical energy can be converted directly to mechanical energy — in an electrolytic cell.” Of course moving electrons are a form of mechanical energy, but it is amazing how many think otherwise.
Thus, my frequent statement is validated that electrical energy is indeed a carrier of energy, like mechanical energy in form of a rotating drive shaft of a car is a carrier of energy. It most certainly is not a fuel that must be first made into heat and then converted to mechanical energy.
I strongly recommend reading “Entropy Demystified” by Arieh Ben-Naim.
Steve (540, 7 November 2009 @ 5:00 PM):
I am having trouble understanding what your point is so, to be clear– All of the energy released from burning a fossil fuel to move a vehicle (your bullet train example in #512) over some distance, stopped at the same altitude as it started from and cooled down, will have been converted to heat. Do you agree with this, and if not please answer the question, where is the non-heat energy stored?
In #512, you said– “It was used to do work. Work = F x d, right? Sure, you can equate that to “heat” on paper, but it’s not the kind of heat that goes into making the system’s temperature increase (thermal energy).” — But this is not true. Where is the non-heat energy stored?
Steve (the fish)
Rene post, 7 November 2009 @ 5:09 AM, inserted, delayed, as #522 and, thereby, bumping my #545 down to #546 (and everything else from there on down one #) and my response to Steve’s #540 to #541. Such unnecessary complications.
Rene:
What you say may be correct, but the main point is that Raypierre’s analysis of Levitt showed a complete disregard for physical reality. This fact makes anything else he said suspect. If you wish to support whatever Myhrvold has said on his own, this should be the subject of another topic.
Steve
545 David B. Benson,
Thanks, it looks interesting. At present, the readily understandable corollaries that in part explain the relations between heat and mechanical energy, whether it is in the form of moving mass or moving electrons, are adequate to establish the degree of our energy problems.
My main concerns relate to the fact that releasing vast amounts of heat in the process of making electricity is so widely accepted and even promoted by government action.
First concern is the fact of government promoting “smart grids” which are smart mostly for window dressing but in reality are intended to improve long distance transmission; and though this is fundamentally a good thing, the effect is more like ultimately perpetuating our system of central power plants where heat can not be used. Thus we reduce loss by a few percent, maybe, and continue to throw away 60% to 70%. And heat thrown away is CO2 emitted without benefit.
Second concern is government promoting of electric cars with associated batteries. This has little effect regarding CO2. However, it will be very effective in shifting from oil to coal, and though this will be important in foreign affairs, it will encourage energy guzzling by vehicles. And it could have a modest effect on CO2 emissions, the fact that energy guzzling will be very affordable will mean that energy will indeed by guzzled. And imagine trying to stop this once we learn that the taste of power is nearly perpetual due to the availability of cheap coal in vast quantities.
RodB:
“A person with common sense,” since they’re trusting that the experts in the field know what they’re talking about.
Thanks Lynne. Getting closer.
It’s a little light on facts, mind.
It says that there are papers saying how biochar can last 2000 years, but is this while it is increasing the plant carbon cycle or just left inert sitting there and doing nothing to the soil.
My concern is that biochar inserted into the soil to improve it will only sequester a relatively small amount of carbon and therefore be useful only as a stop-gap to buy some time.
As an agent to increase yields without pouring more chemical wonders on the ground it always made sense, but is this the benefit to concentrate on for this?