RealClimate logo

An open letter to Steve Levitt

Filed under: — raypierre @ 29 October 2009

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

2 trillion Watts/(.15 X 250. Watts per square meter)

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

(4 Watts per square meter) X log2(1.3)

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

807 Responses to “An open letter to Steve Levitt”

  1. 601
    Lawrence Coleman says:

    For some sober reading take a look at arctic report card link-
    Under atmosphere and mean air temps going back to 1900. Take a look at the I the only one expecting a new record air temp for the 2010 northern summer and a corresponding record shrinkage of summer ice area. The graphic is pretty convincing isn’t it! This site is my one-stop shop for arctic conditions analysis.
    Congratualtions! Gavin for a timely mention in Science daily re: your greenhouse gasses interactions study.

  2. 602
    PHG says:


    “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…”.”

    To give you some further perspective on our project, 35% of the cost of $2500/kw is contained
    in the installation labor and cranes, foundations, grounding, 34.5 kV collector system, 34.5/240 kV
    substation, 240 kV transmission line, fiber optic based SCADA system, wind farm voltage control system,
    cold weather package and extended warranty.

    Now I can also slap a single turbine in a local farmers field, connect to a 25 kV distribution line
    and reduce the installed cost to around $1800 to $1900/kw. One could also select lower cost turbines
    such as fixed blade induction generators as compared to double fed induction generators or full convertor generators albeit with reduced efficiency and loss of certain control features.

    In terms of the ROI, we evaluate projects based on a ratio of the net present value of cash flow generated
    divided by the net present value of maintenance and operating expenses plus capital costs. For renewable projects we would like to just make money, ie: a ratio of 1 to 1.1 which gives at most a 10% ROI or
    roughly a 10 year payback.

    Wind turbines are evaluated over a 20 year period as that is the maximum lifetime the manufacturers will certify. Some will extend to 25 years after inspection of the tower and foundations to ensure there is no
    fatigue cracking etc.

    I’m not familiar with Australian installations but have looked a bit at the wind industry in Denmark,
    primarily because of the high ratio installed wind capacity. Unfortunately, it’s difficult to sort
    out specific pricing because Denmark decided to go the subsidy route to encourage not only local
    installation of wind turbines but also to develop an export market in turbines, which they appear
    to have been very successful at. Also Denmark is geographically small, with a much denser population
    and with strong utility connections to Sweden/Norway and Germany. I would expect them to have a lower
    installed cost for those reasons alone.

    “There’s actually a heck of a lot to be done making turbines that respond better to low wind conditions.”

    Possibly, although it would be site specific. Our wind regime is a Class II category with an average
    wind speed of 8.5 m/s. The turbine is designed to reach peak efficiency at the average wind speed, at
    higher speeds the turbine blades are adjusted to maintain a constant power output up to the cutout speed
    of 20 to 22 m/s where the turbine shuts down to avoid damaging mechanical stresses. The cut in speed
    is 3 to 3.5 m/s but the amount of power and time at those low speeds are minimal. To move to a lower
    speed would require longer rotor diameters and compromise performance at higher wind speeds.

    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).

    There is always arguements about which approach is the best distributed generation close to the load versus larger scale wind farms. To maximize the output of the turbine it needs to be sited away from adverse effects such as local geographic features which may contribute to turbulence. Hence the 65 to 100 m towers and
    spacing to reduce wake losses. Ultimately to reach any kind of high percentage of penetration of wind
    into a generation mix I believe the large wind farm is the best approach although there is nothing
    wrong with smaller scale wind turbine installations as well.

  3. 603
    Hank Roberts says:

    > reported to regenerate itself … they seek it out for use and for sale

    That sounds like wishful thinking. A claim that the surface rises slightly isn’t proof even of the observation; it’s certainly no basis to claim that anything “regenerates in situ” by biological activity and shouldn’t be extrapolated into claims that bacteria are doing anything in particular.

    Take off an overburden, underlying material may expand when exposed to more air and water, even by roots growing into the material. Occam’s razor here.

    I vaguely recall the earliest miners believed the metal ores grew back too.

  4. 604
    Rod B says:

    Patrick 027, the Indiana legislature did in fact pass a law setting pi at 3.2. IIRC, this was primarily in response to lobbying (and suspected bribery) from a textbook publisher who mistakenly made pi = 3.2 in a textbook destined for Indiana schools, and didn’t want to bear the expense of reprinting. Lasted for a couple of years, as I recall. Not perfectly relevant here, other than another reminder that science is not perfectly shielded from non-science forces.

  5. 605
    Eric Rasmusen says:

    This post mischaracterizes what the book says about the problem with solar cells. Its point is that their production generates lots of carbon dioxide. Note that the post does NOT quote the book— a deliberate omission? For the quote— and its context— see

    [Response: See here, and here. – gavin]

  6. 606
    Mark says:

    PHG I would have thought that, although Australia may be somewhat cheaper for some of those elements, the Danes reckon 1500 euros installed. Average costs is hard to figure out because any tenable period for finding a reliable average is long enough to show some considerable change in the technology.

    But Denmark, if anything, would be higher in those costs than the US.

    PS The ideas put forward have been to place them high up along the mainly rectilinear streets of a US city and use the buildings to duct winds into a more effective and constant flow.

    I’d find that oddly disturbing myself seeing a turbine that’s wide enough to cross the street sitting that high up. But ideas abound.

  7. 607
  8. 608
    arch stanton says:

    A few comments on biochar-

    I Have found Biochar for Environmental Management: Science and Technology, edited by: Lehman, Joseph, (2009) to be an excellent compendium of well documented essays mostly written to higher standards than what you typically find on the internet. You can read most, if not all of it on line trough Google Books here:

    General comments:

    In contrast to a couple previous comments biochar (charcoal) is produced by heating wood in the absence of oxygen. It drives of the aromatics which are themselves combustible and leaves relatively pure carbon. This reaction can be done in primitive relatively low efficient ways involving traditional kilns in which the energy for the reaction is derived by directly burning part of the feedstock, or it can be done using any of several rather high-tec methods in which all or part of the energy required is provided by outside sources. By manipulating the temperature and time (heat gradient) the output can be maximized for either biochar or condensate “bio-oil” that can be used as a liquid fuel. If all you want from the reaction is biochar the volatile gasses can be feed back to heat the containment vessel and make the reaction reasonably self- sustaining, possibly also with the collection of a small amount of condensate.

    There are a couple economic analyses given in the book. They are not particularly rosy and the admittedly contain many assumptions. Basically the general conclusions that I got from them was: IF you have a source of cellulose that would be burned anyway (logging debris for example). AND you can process it locally (with 50 km is used as an example) to avoid transportation costs. AND you can use it locally (it is much lighter than the raw material so “locally” in this case is somewhat greater than within 50 km). AND you incorporate it efficiently into fields (that would be plowed anyway). AND you consider the subsequent increase in productivity, it MIGHT be economically feasible if some form of carbon credit subsidy is allowed for the sequestration of the carbon (that would have been burned).

    How long it lasts in the soil is dependent upon many things. It is fairly inert. Some of it breaks down quickly; some of it is very stable and lasts for centuries. Part if it oxidizes directly to CO2, part of it is incorporated into the various humeric acids in the soil that can in themselves last for a century or longer. In one study a couple of years ago in northern boreal forests, biochar’s addition to the (rich) soil was actually found to increase the rate of decomposition of the (carbon rich) humus already in the soil.

    I am by no means an expert on the topic. I do encourage interested parties to review the book however. The essays are written from a variety of perspectives on a variety of topics.

  9. 609
    Jim Galasyn says:

    FYI, nominations for the 2009 Weblog Awards are open, and RealClimate has a few noms for Best Science blog: You might want to visit and show RC some love.

    Please don’t re-nominate, just click the little + button — this demonstrates that we can read instructions, unlike the WUWT posters.

  10. 610
    Mark says:

    Rod B, 607 I believe it was legislated because the Bible said it was 3.2.

    This is the origin of the strange wording by Patrick (The Skeptic’s Annotated Bible shows where it says this in the bible quite clearly)

  11. 611
    Mark says:

    OK, not 3.2. Wonder where I got that from? Maybe the Alabama hoax legislation or another attempt to show up local legislators lacking clues.

    The Indiana one didn’t get very far anyway.

  12. 612
    tharanga says:

    Eric, 605: the book mentions both production emissions and this waste heat issue. A reader of the book would have no idea whatsoever that the latter was such a triviality, so the context of the book does not help your case. The production issues are also not as daunting as a reader might take away from the book.

    The authors felt the need to write a few sentences about this issue. They should have actually given some quantitative analysis on their points, instead of leaving it with some hand-waving, giving the impression that the problems were worse than they actually are.

  13. 613
    Ben Lawson says:

    If you want to reach the same “vote” comment for RealClimate, follow this link:

  14. 614
    Bud says:

    RE: #609

    As amusing as it was to see a bunch of ‘me-too-me-three-me-seventy-seven’ comments from Anthony’s mob, I’m not keen on the idea of the Best Science Blog becoming a contest on which climate site has the most fans who give a toss about internet polls.

    [Response: Actually, I think it would be most illuminating if it came down to a race between the obvious (denialdepot) and the not-so-obvious (WUWT) parody science sites. It would clearly underline the difference between actual science and populism.- gavin]

  15. 615
    tharanga says:

    Gavin, I know it’s house policy not to trumpet your own publications, but the blogosphere is drawing odd conclusions from your group’s paper in Science, “Improved Attribution of Climate Forcing to Emissions.” It gives some interesting analysis of atmospheric chemistry and methane’s interactions with other forcings, but via Al Gore and Newsweek, the blogosphere has turned it into ‘now they say CO2 is not important, after all’. Perhaps some comment is in order.

    [Response: Yes, I noticed. Plus it got both Pielkes and Watts to say something nice about our work with climate models (at least implicitly). I do have a post on various methane related topics in the works (including some discussion of our Science paper), so we can discuss it then. – gavin]

  16. 616
  17. 617

    Hank, I’m reporting what the source said, not speculating myself (well, maybe a little with the bacterial activity bit.)



    Neither specifically addresses the regeneration question. However, the NatGeo link has this:

    The terra-preta charcoal, called biochar, attracts certain fungi and microorganisms.

    Those tiny life-forms allow the charcoal to absorb and retain nutrients that keep the soil fertile for hundreds of years, said Woods, whose team is among a few trying to identify the crucial microorganisms.

    “The materials that go into the terra preta are just part of the story. The living member of it is much more,” he said.

    For one thing, the microorganisms break up the charcoal into smaller pieces, creating more surface area for nutrients to cling to, Woods said.

    Possibly this dovetails with your idea of mechanical expansion via root action. But it definitely goes to the long-term stability–and, more, fertility–of the soil, whether or not it actually regenerates as claimed. (BTW, I was wrong to sniff at the “thousands of years” claim in the Wiki article, too–I’d misread the “450 BCE,” which does indeed give ages of over 2,000 years for these anthropogenic soils.

    But the takeaways ought to be that 1) the terra preta is effective and long-lasting as an amendment for tropical soils, 2) that there seems to be good support for the idea that it can be effective in sequestering carbon over a timescale of centuries to millenia, and 3) that it can be done cheaply and without much technology.

    Or so I read it.

  18. 618
    Dale says:

    I know this is off topic but I’m not sure when it would be appropriate.

    I’ve been following the discussions here for the past 18 months. Not having any degree in science (100 level biology course) I still enjoy science.

    I first became aware of the issue of Global Warming in a December 1988 edition of Time magazine while I was visiting Australia for its sesqui sentenial. Back in those days, as I remember only a minority of scientists bought into the idea. Over the years I’ve seen the majority of researchers in the different fields come more and more to accept the idea that man made CO2 is playing havoc with our world.

    I think what we need IMHO is an interesting narrative that explains how we got to the point of consensus. There were obviously many scientists in all different disciplines from engineering, physics, chemistry, biology, geology just to mention a few. Those doubting researchers then ran data and experiments that brought them to believe it as well. Make it an interesting and dramatic a story as possible(Sex it up)without using all the scientific facts that make peoples eyes glaze over! It might make it more compelling and easier for people to accept it. Just a thought.

  19. 619
    PHG says:


    “Oh, and some info on gridding up wind power:”

    Yes, being able to accurately predict wind is key to successful integration.

    There is an ongoing program in our area to accomplish the same thing.

    Thanks for the link, a good news story.


  20. 620

    Dr. Woods’ publication record is here:

    Certainly a productive researcher. . .

  21. 621

    Dale, I’m at work on such a project, more or less. It’s a series of articles, already familiar to a goodly number of readers on this site. Start here.

  22. 622
  23. 623

    In #609, the following:
    “FYI, nominations for the 2009 Weblog Awards are open, and RealClimate has a few noms for Best Science blog: You might want to visit and show RC some love.

    Please don’t re-nominate, just click the little + button — this demonstrates that we can read instructions, unlike the WUWT posters.

    Comment by Jim Galasyn — 9 November 2009 @ 11:54 AM”

    Thanks for the pointer — I went over there and gave another vote. I was struck by how many votes Wattsupwiththat got!

    Note to Mark: I am not suggesting that latter site is to be taken seriously.

  24. 624

    Mark: Rod B, 607 I believe it was legislated because the Bible said it was 3.2.

    BPL: There is no such passage in the Bible. Some people take a verse in I Chronicles to mean the Bible says pi = 3 because the chronicler describes Solomon’s molten pool as being 10 cubits across and 30 around, but there’s no reason to think the chronicler wasn’t simply giving an approximate figure. He was praising his king, not explaining mathematics, which he may well not have known anything about. The Hebrews had lived among the Egyptians, who estimated pi = 3.16, and the Babylonians, who estimated pi = 3.12. They would have used one or the other of those.

  25. 625
    David B. Benson says:

    Andrew Hobbs (584) — Of course it is not at all bizarre when transportation costs are taken into account. It may make perfectly good sense for the coal user to pay to have carbon offsets done on another continent, for example. If the carbon offsets include the prepartion and burying of biochar, that is a fairly local operation, avoiding significant transportatin costs.

    Jim Bullis, Miastrada Co. (585) — The change in South Carlina does not invovle any payments from govenements. The privately owned utility company, Souther Power(?), pays the woodlot owners for the torrified wood to burn in their 400 MW burner being converted from a coal burner while being relicensed. Sources such as sawdust have largely been in use for decades, at leat in Maine and around here; point sources of fuel are lower coast, so used all the sooner.

    Jim Bullis, Miastrada Co. (586) — Carbon neutral is a h**l of a big deal because right now the world economy is heavily carbon positive. With the hoped-for eventual replacement of coal burners by renewables, afforestation and biochar burial projects then contribute to being carbon negative. The sooner that happens, the better IMO.

    Steve Fish (588) — I believe the lack of soil nitrogen is thought, in the Ornstein et al. paper, to begin by first planting a crop of acacias.

    Patrick 027 (591) — I believe all those issues are addressed in the linked Ornstein et al. paper; the pdf is open access so everyone can read it.

    Mark (595) — THe previously linked report directs one to cases where the buried carcoal has lasted far longer than a mere 2000 years. The one case I recall, possibly not in the report, is charcoal deeply buried in the Ukraine, estimated to be about 40,000 years old.

    Richard Steckis (598) — Then by all means go for it!

    Kevin McKinney (600) — THere is a big difference between biochar, a form of mostly carbon, and terra preta, a soil including a larger than usual fraction of carbon, just from charcoal originally. Yes, it is possible for people to build soils rather than just deplete; good gardiners and farmers do it all the time. Putting some biochar into soils, most soils anyway, certainly helps to build soil amount and quality.

  26. 626

    To Dale: (#618) — The book by Weart comes close to your wishes; perhaps though it is a bit too technical.

  27. 627

    Sorry — the Weart book is THE DISCOVERY OF GLOBAL WARMING, by Spencer R. Weart, 2008. I just looked at it again — I suspect most people high school and above would have no trouble with it.

    Gavin Schmidt’s book, just issued, CLIMATE CHANGE is another possibility. More up to date than Gore’s AN INCONVENIENT TRUTH.

  28. 628
    David Miller says:

    Regarding weather changes from an open arctic from Lawrence Coleman in 601:

    You’ve brought up a good pointer to what I feel may be a huge “unknown unknown”. It strikes me that having all the extra energy absorbed “on top of the world” and expressed as warm and humid air that goes *somewhere* has to change normal weather patterns somewhere.

    If anyone has reference to any papers/models/studies on this effect I’d love to see them.

  29. 629
    David Miller says:

    Regarding significant percentages of “biochar” disappearing in the first few years:

    Has anybody seen studies of this? My guess is that the actual carbon would be very stable because it’s not part of any normal metabolic processes and doesn’t oxidize outside a fire.

    What’s usually called “biochar”, however, contains a percentage of ash containing water soluble minerals. These minerals (calcium, magnesium, phosphorous, potassium) would either leach out or be taken up by plants; it’s natural they’d be lost.

  30. 630
    Hank Roberts says:

    > Has anybody seen studies of this?

    David, look back in the thread a dozen or two responses, I posted an example of how to search, and an example of one paper from the search results. You can find this, if you use Google or Scholar.

  31. 631

    I followed up on the terra preta question via an email to Dr. Bill Woods, who is cited as the authority on the subject. I was startled to promptly receive a brief but pleasant note stating, among other things, the following:

    “Basically, the situation is that the microorganisms and fungi in the terra preta thrive, live and die, and produce biofilms on the minute surfaces of the soil particles and thus darken the soil again if 20 cm or so are left after the mining operation. All soils do this if there is sufficient life and nutrients. It’s just not common in the tropics.”

    So there is a regenerative process of some sort; it’s not clear to me just what, exactly, is being regenerated, other than the dark color and the enhanced fertility; nor what that means for the question of carbon sequestration. I’m hoping more information will be forthcoming. If so, I’ll update RC.

  32. 632

    625 David Benson,

    If you owe a bank a million dollars and it is due tomorrow, no one is going to be impressed by you working really hard today to raise $100. Your day will be “money negative” in the sense of the “carbon negative” way of talking. You might claim you did not hurt anything and actually could get credit for the $100 on your, but the money collector will come around just the same.

  33. 633
    Brian Dodge says:

    @Comment by Patrick 027 — 8 November 2009 11:45 PM

    According to a reliable source, (and by reliable, I mean “something I found quickly on the internet at a site which probably is maintained by people who don’t have a vested interest in lying to me, and whose statements can actually be easily cross checked”, not “something I’d bet more than a case of beer on”), the House passed the bill, but “According to newspaper accounts, Senators treated the bill as an occasion for frivolity, making numerous jokes and puns at the bill’s expense,” letting it die. But yeah, I woulda used it even if it’s only an urban legend.

    According to “ENVIRONMENTALLY SOUND DESALINATION AT THE PERTH SEAWATER DESALINATION PLANT,” Richard Stover, Gary Crisp, the real life energy requirements are 3kwh/m^3. Assuming I got my math right, this works out to ~83m^3/GJ, so your “back of the envelope” calculation is optimistically inaccurate, but within a factor of ~4. “The Water Footprint of Energy Carriers”, Winnie Gerbens-Leenes, Arjen Y. Hoekstra and Theo van der Meer states that the “Water Footprint” of crops in the US averages 60m^3/GJ, and corn only requires 18m^3/GJ, sugarcane 30m^3/GJ.This would imply that some crops could produce the energy required to desalinate the water required to grow them. Gerbens-Leenes figures show a worldwide range of water use from 9m^3/GJ yield for maize in the Netherlands to 356m^3/GJ for cotton in Zimbabwe, so there are clearly places where the crop-biofuel-electricity-desalination-irrigation won’t work, but with the right crop and careful attention to maximizing yield, irrigation effectiveness, and conversion efficiencies, farming could generate its water requirements from biopowered desalination. In “Feasibility of Biomass Energy Production to Support Local Water Self-Sufficiency” from the California Department of Food and Agriculture, they propose using the existing allocation of water to the Imperial Valley to grow crops which would be used to generate electricity which would be used to desalinate seawater for the LA-San Diego area. Their calculations show that the electrical power for desalination would only be about 50% higher than the powered required to pump the water over the mountains, and wouldn’t require construction of new aqueducts, pipelines, pump stations. It would also provide an economic boost to the Imperial valley, not incur job losses which would occur with reallocation of the water to the coast, and reduce the fossil carbon footprint of supplying water for future urban growth.

  34. 634
    Steve Fish says:

    David B. Benson ~#625, 9 November 2009 @ 2:56 PM):

    I have read the proposal, no need to repeat. Acacia was secondary to the suggested legumes. I repeat, Ornstein et al state that growing legumes/Acacia will make “sand” suitable for growing Eucalyptus. Are you defending this?


  35. 635
    David Horton says:

    #633 … and require somewhere to dispose of the salt other than dumping it on land or sea.

  36. 636

    Jim Bullis #580: we have some truly
    weird stuff in Australia. First, the feed-in tariff is paid for by a
    tiny increase in general electricity tariffs. Second, the government
    has will lend you up to $10k (AUD, about USD9k) @ 0% for home
    energy efficiency and clean power. Third, they allow you to claim 5
    times the actual energy value of your solar power in renewable energy
    certificates (aka phantom RECS). The first 2 make some kind of sense;
    phantom RECS don’t. Investing tens of billions of dollars in a big
    expansion of coal export infrastructure as is happening here makes
    even less sense.

    As for battery cars, I presume you are talking about vehicle to grid
    (V2G): a nice idea, but the car batteries need to be designed for this
    sort of discharge and recycle pattern, and you need a good fraction of
    the population to have their cars plugged in over peak demand (nice
    for power utilities: the last 1% of demand costs 100x the cheapest
    power). The best way to achieve that is to leave most of them at home
    over the working day, i.e., high use of public transport. That adds
    another potentially nice feature. If you have electric trains and
    buses with battery backup, they can run on the grid when power is
    cheap and plentiful and switch to battery when it’s not.

    If anyone thinks this is totally OT, let me add: this is the kind of
    stuff economists should be talking about, not misinterpreting the
    science to stir controversy as a shabby tactic to sell a book.

    there doesn’t seem to be any reason not to click “+” on every instance
    of a nominated blog. In any case, this is an initial vote to pick
    finalists. I encourage anyone posting comments there not to get into
    “you’re a bigger one” fights with denialists, but invite would-be
    voters to check realclimate for themselves to see if the attacks are

  37. 637
    Hank Roberts says:

    Well, heck, you want sulfates, there’s the natural way:

    “… Campi Flegrei is “one of the highest risk volcanic areas on Earth” and may now be primed for a blast. Isaia and colleagues found deposits from an intense period of eruptions around 4000 years ago. Before the eruptions the Earth’s crust rose by several metres all across the caldera. Worryingly, crustal uplift is exactly what has happened recently. Since the late 1960s, the port of Pozzuoli near the caldera’s centre has risen by around 3 metres. Hazard planners should prepare for eruptions in decades or less, Isaia concludes (Geophysical Research Letters, in press).”

    How big?

    >> The volcano has no visible cone but it dwarfs Vesuvius, and most of Naples is in its caldera

    “A major eruption, like the one 39,000 years ago, would leave large parts of Europe buried under a thick layer of ash ….”
    It sounds like the geologists, for decades jealous of the physicists’ ability to produce rapid energetic disassembly events, may be on the verge of discovering sin for themselves.

  38. 638
    Patrick 027 says:

    Re 636 – Philip Machanick – actually, my understanding is that Jim Bullis favors burning fuel in (very aerodynamic) vehicles (in hybrid electrics?), and when parked, using vehicle engines to supply electricity and heat to buildings/grids.

    I like the idea of converting existing residential furnaces into cogeneration plants (nice winter/night supplement to solar electricity, heat, and light, etc.). Jim Bullis’s plan seems a bit ungainly to me but maybe that’s bias on my part.

  39. 639
    Patrick 027 says:

    cogeneration plants –

    Preferably using thermoelectric or thermophotovoltaic devices.

  40. 640
    Patrick 027 says:

    Or… feed fuel into fuel cells and use the waste heat from fuel cells.

  41. 641

    PHG @ 619:

    Predict or react — don’t much matter since the total amount of wind energy produced is the same, assuming wind is allowed to run, rather than being idled.

    This is why efforts in Demand Response and storage are so important.

  42. 642
    Dale says:

    Once again I know this is off topic but I was wondering if anybody has seen this? “New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now.”

  43. 643
    Ike Solem says:

    Fossil fuels emit fossil carbon to the atmosphere, and that’s an unavoidable consequence of combustion. Trapping and permanently storing the carbon emissions would use as much energy as could be obtained from the fossil fuel.

    Thus, the real costs of fossil fuels – global warming, pollution, health costs, military conflict due to increasing scarcity – clearly demonstrate that renewables are cheaper in the long run. Even on a straight accounting basis, a power plant that uses free fuel (wind and solar) to generate electricity will obviously have lower costs than one that relies on a steady steam of coal or petroleum or natural gas. The only way this would not be true is if up-front and maintenance costs for wind and solar plants were far higher than for coal – but that’s not the case, is it?

    Consider nuclear, for comparison. Fuel costs are lower than with coal (tens of millions of tons of coal are replaced by hundreds of tons of LEU fuel), but upkeep and maintenance costs are higher – more water is used, and high temperatures and pressures are involved, and redundant processes are used to avoid accidents.

    Solar and wind, in comparison have all the low-cost fuel advantage plus low maintenance costs. The big barrier that needs to be addressed is energy transmission and storage – and let’s not forget more efficient technology for the energy consumer, as well. The Obama Administration’s push for a better grid is therefore encouraging – that was the central problem with the Pickens wind project for Texas, lack of distribution.

    The bottom line is that if fossil fuels vanished overnight, we would have the technological capability to replace those energy sources with wind and solar and photosynthesis. Take a look at the DOE’s new Direct Solar Fuels initiative, or even at ExxonMobile’s new algal biofuel program, for some examples. (One has to like Exxon for putting money into a truly clean hydrocarbon fuel program, rather than backing nonsensical “CO2 capture projects” as part of a greenwashing campaign, as Chevron and Conoco and BP and Shell like to do. At the very least, they will be better positioned for the future.)

    By the way, did anyone see this little notice on Leavitt’s book? Apparently someone posted the “global warming” chapter online under fair use laws, and the publisher (Harper Collins) is busy sending out cease-and-desist letters:

    SuperFreakonomic science fiction, Salon, Tues Nov 10 2009

    In the annals of bogus Digital Millennium Copyright Act (DMCA) takedown notices, the directive from Harper-Collins ordering Berkeley economist Brad DeLong to remove from the Web the PDF of Chapter 5 of “SuperFreakonomics” that he posted a few weeks ago is not actually an out-of-bounds request. There’s little doubt that DeLong actively wanted to embarrass “SuperFreakonomics” authors Steven Levitt and Stephen Dubner by exposing their “global warming” chapter to public scrutiny. Even bad publicity is usually welcomed by publishing companies, but in this case, the storm of ridicule showered upon “SuperFreakonomics” may ultimately be too much of a bad thing.

    In particular, see this quote from Elizabeth Kolbert, the New Yorker:

    To be skeptical of climate models and credulous about things like carbon-eating trees and cloudmaking machinery and hoses that shoot sulfur into the sky is to replace a faith in science with a belief in science fiction.

    This book wasn’t written by some quack, either, but by one of the nation’s “leading economists” at a school known for ideological conformity to the Milton Friedman vision of economics…

    Here’s a suggestion: put economics under the academic control of science departments, not business schools, and make economists learn basic science – such as thermodynamics, conservation of energy, etc. – and then you might see science-based economic arguments moving to the fore, rather than this kind of blatant industry propaganda.

    How to begin? First, economists should pick up a copy of the very authoritative Princeton Guide to Ecology – unlike with Leavitt, they put a few chapters online for free, and the one to start with is Ecological Economics:

    Don’t waste your time with Leavitt – read this instead:

    Ecological economics studies the interactions and coevolution in time and space between ecosystems and human economies. The rate at which humans exploit or harvest ecosystems services exceeds what might be regarded as a desirable level from society’s point of view. The consequences of this overexploitation are well known (e.g., climate change, biodiversity loss and extinction of species, collapse of fisheries, overexploitation of water resources). The objective of designing economic policy is to develop a system of regulatory instruments so that the state of the regulated ecosystems will converge toward the socially desirable outcome. The purpose of this chapter is to present an approach describing how economic policies might be designed to achieve this objective.

    In the Leavitt Friedman Chicago view, these ecological factors are simply lumped as “externalities.” That’s translatable as: “things we don’t want to have to think about.”

  44. 644

    Patrick 027,

    Thanks for the succinct summary. You can remove the question mark after hybrids, though I try to retain flexibility here. It would make sense for many to simply use all electric for commuting, and since the aerodynamic losses are so low this becomes feasible. Yes, I would burn fuel, but only about a fifth as much as we do now in a typical car.

    But I see economics as a major system design consideration. My approach does not require people to buy extra stuff, rather they would be replacing stuff they now have with something that better meets their needs.

    Cogeneration is very effective if all the heat is used, and in fact the system is operated in that mode only when all the heat can be used. This is possible with machines in a household, but why not use the machines that are sitting outside and you already have paid for?

    I have to agree with you on the “ungainly” part, though it might be more a matter of what we are used to looking at than anything else. It is truly an impediment to widespread acceptance that I have to face. I think it will turn out that fashion and style are the enemies in the anti global warming campaign. I would not be against making things look nice, but when they are done based on the fashion designer’s misconceptions of aerodynamics, as is the prevailing practice in the auto industry, that has to be limited.

    The ungainly shape is what it takes to get the extremely low drag that made the huge airships feasible. Minor adjustments have been made based on guidance from Morelli, 1982 where he worked out ways to counter the ground effect with a car running close to the ground. I use some of his methods but mostly minimize the ground effect by holding the body as high as possible above the ground. The Aptera using the Morelli shape seems to have ended with a Cd of .15. I am looking for about half of that.

    There is a patent for a car that uses thermoelectric conversion using waste heat from an engine. This has merit though the very low efficiency of thermoelectric conversion means there is still a lot of waste heat.

    Household space heating is the best way I can think of to make use of the lowest temperature point in the heat using sequence.

    It seems conceivable that fuel cells could be used in the same way I use the engine in the car in combination with the heat using household. I can buy the right sized diesel engines today and these would work great, though there still needs to be work on catalytic converters to block NOx release, though that seems far closer than fuel cells. The Prius engine seems to have proven that gasoline can be used far more effectively than we used to think, about 37% thermal efficiency, so that is a technology that only needs to be scaled down to fit my needs. (Scaling down is a nice way to be changing things.)

    But if you can imagine such things working for cars, power generation, and trucks (coming soon) there might actually be workable solutions to global warming of a magnitude that is worth bothering with. Lets kick the hairbrained geoengineering out of the way. And while we are at it we need to do some kicking on the energy guzzling electric car approach and the “smart” grid which will perpetuate our heat wasting central power plant system far into the future.

    Thanks again. Jim

  45. 645
    Hank Roberts says:

    > Ike Solem says: 10 November 2009 at 2:10 PM …

    Bravo! Bravo!

  46. 646
    Naindj says:

    Ike Solem 643,
    These are very interesting thoughts.
    I have remarks/questions about maintenance costs.
    For me, the huge difference nowadays between fossil and renewable (wind or solar) is the scale.
    Fossil are cheaper essentially because you can build huge installations and bring some concentrated energy (coal, oils, gas…)
    Nuclear is even better for that. You have 1300 MW in a very small area. Hydraulic the same.
    Solar? Windfarm? You need a lot of space.
    And maintenance, as well as construction, is highly dependent on the number of facilities you need.
    But I am talking general things here (and I am sure I will be corrected by some smart people here). This is what I think. But I clearly lack of figures.
    Does anyone here have a reliable estimation of the return on investment (in terms of energy, so without any subsidy) of a wind farm, solar plant?

  47. 647
    David B. Benson says:

    Steve Fish (634) — Not all readers will have read the paper; I find repetition to be quite useful, if not strictly necessary, in this pecular form of communication.

    As for your question, I can only answer with the generality that many people in varied locations have found ways to cause deserts to become productive soils; Imperial Valley, California and much of Israel come immediately to mind. With regard to the Ornstein et al. idea, I recommend a pilot project in Tunisia.

  48. 648

    We could trade wierd stuff stories and I am not sure who would win.

    I have nothing against government trying to kick start a good thing with subsidies, but they can lead to some very wrong decisions when it gets to a large scale. You say that the public pays a tiny amount extra to pay for subsidies, but you will surely agree that if everyone acts to collect subsidies, it will not be so tiny.

    I saw a guy in a booth at a farmers market in Oregon last week from PGE talking about selling green credits. I kept on walking since I had looked at this before. Of course, if they want people to advance them money to build wind mills that is fine. However, it does not mean that when these folks plug in a car that the electricity will come from wind mills. In fact, whatever the windmills produce will be used regardless of the plug-in car. So when the car is plugged in, it will draw from the available reserve capacity, which will be coal, even in Oregon.

    Then I picked up a weekend newspaper that described how the cost of wind systems had been vastly underestimated, deliberately, at the behest of the political leaders. Now Oregon folks will be paying far more than planned. And the developer says he would not have built the things without the subsidies. This is not good for the campaign against global warming.

    As for battery cars, they can be useful, but only if designed to not guzzle energy wherever it might come from.

    Using batteries in cars to help out the power company seems like a phony contrivance of an idea that the power companies love. Mostly because it will not amount to much, but also because they get to control the production. Oh yes, we get to think computers will magically make this work effectively. Ok. As far as I can tell there is not much power company enthusiasm for distributed cogeneration of any kind. (There is a provision in California law for small subsidies for this if “properly sized.” Not without some good reasons, the idea of letting the car sit there and produce electricity is not mentioned. (The Prius does not work very well for my car based cogeneration approach because the engine even in this car is too large and will produce too much heat for a household to handle.)

    I argue in general for individual cars which fit with the way people actually want to live and work, which is not in dense urban situations where mass transit functions well. The problem of distribution at both ends of the travel process is far more important than planning folks like to think. Hence, we are stuck with public systems that almost nobody rides on in city after city. Though far more likely to succeed, car pool lanes are far less effective than they have been advertised. (We trick ourselves by allowing mothers to use a kid to qualify as “high occupancy” so there are a few people in some carpool lanes, which cost many $billions. We were told that the carpool lanes take cars off the road, but much as we are in favor of mothers and babies, they do not represent cars taken off the road. — I could go on.)

    Even freight transportation is subject to the same distribution problem. Only when freight moves from a single point to another single point is a rail system really effective. Guess where that situation applies? Wrong Answer: Mass transit of people. Right Answer: Coal mines to coal fired power plants. The coal train is so remarkably effective that we really do not care much that the coal fired power plant throws away 70% of the heat produced from the coal. (You may have heard about Warren Buffet buying the BNSF railroad. This reality is not lost on him — 50% of BNSF revenue is from hauling coal.)
    And Warren Buffet might also realize that the big push to shift from oil to coal as the fuel for cars under the government encouragement to build electric cars will lead to ever larger coal train profits. This will help with oil dependence problems, but it will not be good for the global warming campaign.

  49. 649

    643 Ike Solem,

    You say, “The only way this would not be true is if up-front and maintenance costs for wind and solar plants were far higher than for coal –but that’s not the case, is it?

    It looks like it is the case when you include the need to keep back-up generation ready to cover the variability of wind and solar as well as count the cost of investment money that has to be put out up front, as well as the things you mention. In the search for truth, a clue is that investors are not willing to have any part of these renewable schemes unless the public subsidizes the costs, guarantees the rates, or penalizes the coal competititon in some combination of chicanery.

    Certainly all the real costs need to be considered including the human value judgments that are every bit as important. These need to be laid out clearly. It is not helpful to the campaign against global warming when there is a contrived attempt to put numerical values on the negative impacts of coal. We need to know how the effect are really manifested. Pretending that everything is numerical is only an annoyance.

  50. 650
    tharanga says:

    Ike: If you want to use “straight accounting basis”, without taking all those externalities (pollution, warming) into account, you should actually look up numbers, and not just make guesses. You can find ‘levelized’ costs for coal, gas, wind, solar, etc, in that construction, fuel, labor, financing, and maintenance costs are included. You’ll see that coal and natural gas still have the edge, though wind can sometimes be just as cheap (especially if you add in available subsidies), and local policies can make coal more expensive. Also, if use of wind requires new transmission lines or some facility for storage, you have to consider that as part of the cost of expanding wind; that doesn’t come free.

    See the discussions between me, Mark and PHG here. When you see numbers, keep in mind caveats that local circumstances can change the costs, and that promoters of a given technology like to quote the low end of the cost range. I trust the DOE’s numbers the most, but I can’t find the exact link now. So if you look around, you’ll see costs like 3-7 cents/kWh for traditional coal or natural gas; anywhere from 10-40 cents/kWh for various forms of solar; guesses at anywhere from 7-30 cents/kWh for newly constructed nuclear; wind anywhere from 5-10 cents/kWh.

    “The bottom line is that if fossil fuels vanished overnight, we would have the technological capability to replace those energy sources with wind and solar and photosynthesis.”

    It’d take several years to build the needed infrastructure, even if those other sources were reasonably priced.

    None of this should be interpreted as me saying “we can’t” or “we shouldn’t.” We should put in a carbon price to level the playing field, and maximum effort should be continued in R&D to reduce the costs of renewables. It just bugs me a bit when environmentalists are good with the science, but a bit dreamy on the economics.