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Gee-Whiz Geoengineering

Filed under: — raypierre @ 25 October 2007

Just about two years ago, Chemistry Nobelist, and atmospheric scientist Paul Crutzen opened a huge can of worms by suggesting that, since the world doesn’t seem to be getting its act together to significantly reduce CO2 emissions, it would be prudent to think about emergency measures in which we engineer ourselves out of the crisis by monkeying directly with the Earth’s solar radiation input instead of dealing with the CO2 content of the atmosphere. The specific proposal was to inject chemicals into the stratosphere that would form sulfate aerosols and hence block sunlight. Crude estimates suggest that the aerosol fix (if it is indeed a fix and doesn’t create more problem than it solves) is more technologically feasible than sci-fi dreams of sunshades at the Lagrange point. Not to say technologically feasible, necessarily, but not so far out as the other schemes. Crutzen’s idea, and related geoengineering proposals, have been discussed here on RealClimate. The subject is once more in the news, thanks to this chipper little op-ed by Ken Caldeira, which appeared in the New York Times this week.

Update: I just noticed that our original RealClimate piece was done before Crutzen’s article was published. You’ll find his article here (subscription not required).

The attraction of the proposal is that we are already conducting an uncontrolled experiment on aerosol-based geoengineering, through the sulfate aerosols injected into the troposphere by dirty coal plants. Along with a lot of nasty health and environmental consequences, this has had some inadvertent benefits in restraining some aspects of global warming. As coal plants get cleaned up in the future some of the cooling aspect of the tropospheric aerosols will be lost. Since aerosols last much longer in the stratosphere than they do in the rainy troposphere, the amount of aerosol-forming substance that would need to be injected into the stratosphere annually is far less than what would be needed to give a similar cooling effect in the troposphere, though so far as the stratospheric aerosol burden goes, it would still be a bit like making the Earth a permanently volcanic planet (think of a Pinatubo or two a year, forever). It might make sense to take a small portion of the aerosol that would have been dumped into the troposphere by retired dirty coal plants, and inject that directly into the stratosphere where it will restore the lost cooling effect while (hopefully) doing less harm than the old stuff dumped into the lower atmosphere. To go farther, though, and count on offsetting the entire unrestrained CO2 production of the coming century with engineered aerosols is fraught with peril.

Scientists just love to think about this kind of stuff, and I’m no different.Harvard is hosting a small workshop on aerosol-based geoengineering, and I have to say I’m looking forward to it. It’s like having a shiny new toy, and the chance that you might actually get to use it to play around with the real Earth and see what happens has a certain fatal attraction to it. Then, too, science thrives on a spirit of free inquiry, and it would be anathema to say that there are some things that just shouldn’t be thought about (though there are certainly some things that, once thought about, shouldn’t be built). But, there’s a real danger of jumping the gun and giving the impression that we already know we have a way out if things get too bad. Ken Caldeira’s Op-Ed is a case in point. “Which is the more environmentally sensitive thing to do: let the Greenland ice sheet collapse, or throw a little sulfate in the stratosphere?” is the way he frames the issue. To be sure, Ken only gets 400 words to make his case (which seems to be that the folks who work on this sort of stuff ought to get some more money), but those 400 words leave little room to explain the vast array of problems that need to be resolved before we can even begin to think of this as an out. Caldeira’s Op-Ed makes it seem like a slam-dunk, needing maybe only a diversion of 1% of climate research funds in order to do the trick.

Here are a few of the problems that need to be worked out: There’s the issue of the effect of the aerosols on stratospheric chemistry (think how unanticipated the chemistry of the Ozone Hole was), and the question of just where the aerosols would go once injected. There’s the question of the effect of the aerosols as cloud-condensation nuclei if they work their way into the tropical upper troposphere — an increase in high cirrus clouds could well lead to warming. Then, there’s the full range of possible effects on the atmospheric circulation. Held and collaborators (PNAS 2006) have implicated the joint effect of aerosols and greenhouse gases in the trend towards Sahel drought, and generally there are issues in what inhomogeneous aerosol forcing might do to things like the North Atlantic Oscillation. Also, a planet with a dim Sun and high CO2 is not the same thermodynamically as a planet with brighter Sun and lower CO2, because the reduced sunlight at the surface is not able to sustain as much evaporation, which has consequences for global rainfall. In a recent essay in Le Monde, Edouard Bard has pointed out additional problems with geoengineering.

In my mind, the most serious peril of sulfate geoengineering is one that stems from a problem that is not at all in dispute: the fact that the lifetime of CO2 in the atmosphere is centuries to millennia, whereas the lifetime of aerosols in the stratosphere is at best a few years. That means committing the future generations to continue the aerosol injection basically every year more or less forever. We’re banking a lot on confidence in future stability and prosperity of the world here. A patrician in the glory days of the Roman Empire might well have expected the Pax Romana to go on forever, but really nobody expects a Dark Age.

One also has to wonder whether the international treaties and organizations needed to agree on and execute a geoengineering scheme are significantly easier to realize than the agreements needed to decarbonize the energy future, which would offer safer and more durable climate protection. And once you open the Pandora’s box of geoengineered climate, what do you do if nations disagree about what kind of climate they want, or if some poor nation objects to suffering drought in order to cancel heat waves in Chicago? Great fodder for science fiction novels about climate wars, but I’d prefer not to have to think about it happening for real.

The problem is that geoengineering a sunshade is being sold as insurance long before anybody has any idea whether it would work and what the unintended consequences would be. It’s not really insurance. It’s more like building a lifeboat, but a lifeboat based on a design that has never been used before which has to work more or less perfectly the first time the panicked passengers are loaded into it. The problem is that by the time we know enough to have any confidence at all in this lifeboat, CO2 may have risen to the point where the lifeboat becomes not just a backup, but a necessity. Would diverting 1% of the world’s climate research funds into this problem clarify the issues in time? I doubt it. Would devoting 10% a year to the problem be worth it? I doubt that, too, in comparison to more pressing research needs.

Now, can we please get back to the serious business of trying to figure out how to economically reduce global CO2 emissions?


213 Responses to “Gee-Whiz Geoengineering”

  1. 101
    John L. McCormick says:

    RE # 92

    Dave, I disagree with your comment that:

    [in my view anyone on either side of the nuclear debate who characterizes the other side as all being irrational are themselves being irrational.]

    You likely are fairly agnostic about a nuclear power future but you also repeat the same litany of complaints the anti-nuke crowd throws up at every conceivable opportunity. Ironically, most of those voices tell us at every opportunity that civilization has only a decade or two to save the planet’s ecosystem from a global warming free fall that triggers eventual total chaos…meters of sea level rise, perpetual drought…. add your scenario here.

    Now, compare that sliver of open window opportunity to the anti-nuke campaigners slogans of disposal challenges, costs and risks for thousands of years. Is that a rational balancing of concerns or are those voices so ignorant of the progress being made by engineers in South Africa, China, France and elsewhere to take the pebble bed nuclear reactor to the commercial deployment stage in this next decade.

    Global warming is not an environmental problem. The environment is the victim. It is an engineering and environmental challenge of superhuman dimensions.

    That the environmental community and activists are not heavily endowed in the science and engineering side of the issue they are so passionate about (and no more passionate than I) is understandable. It takes time and diverts attention from their campaigning to push back and grapple with the hard facts of the modern world and the rapidly expanding lesser-developed world.

    Electricity and petroleum are on a level with food and water to maintain survival of a massive civil population. As US population grows so does its demand of electricity and oil. All the hand waiving and admonitions of less-is-beautiful advocates will not change the direction of the increasing demand for electricity and oil throughout the world.

    Until we environmentalists put down the placards and banners and come to grips with the massive challenge of meeting the needs of an expanding world economy our movement will forever be typecast as made up of ludites and dreamers who really believe Americans will bicycle and walk to work even if the weather is ugly.

    The world does not work as the anti-nuke campaigners think it does. If there is an analogy to that thinking, I say it is the neo-con belief the US can dictate its terms of democracy-forming of people and nations we have no fundamental understanding who they are and how they operate.

    Search the pebble bed literature and see if some of your concerns might be alleviated, if only a bit.

  2. 102
    Hank Roberts says:

    Dean wrote:
    > Assume for a moment that … CO2 is not causing global warming

    Makes no difference; CO2 from coal is changing ocean chemistry far faster than it’s changing the climate.

    You should know this.

  3. 103
    David B. Benson says:

    Dan Hughes (93) — Of course nobody actually knows what size carbon tax causes how much CO2 emmision reduction. I’ve seen an estimate that $20–30 per tonne of carbon will cause (some) people to forego burning fossil fuels. But currently more than that is required to sequester carbon dioxide, although the sequestration could be subsidized.

    [Response: Also, the relationship between carbon tax and reduction is nonlinear, since the different opportunities for reducing emissions come with different costs. There are a fair number of rather cheap reductions out there that could be stimulated by a low carbon tax, but after a while you use those up, and have to have a higher tax to induce more. An alternate way to estimate reductions is to look at the incremental cost of a particular carbon-abating technology, e.g. building an IGCC coal plant and sequestering instead of building a pulverized coal plant. But basically, it's hard to know how the ingenuity of market participants will play out, which is why the basic idea seems to have been to implement a carbon tax or cap-and-trade system with some initial guess of price, then adjust it after more data comes in. Europe's problem was that they over-allocated permits, resulting in a crash of price. That experiment is therefore not yielding much information at the moment.

    Another thing to keep in mind is the distinction between the gross cost of a carbon tax and the net cost. If you charge $100 a ton for Carbon, that doesn't add up to $100 a ton cost for the whole economy. Some of that will be added back in to GDP through the spending the power company will do to build IGCC plants, and if the tax is made revenue-neutral through tax credits on hybrid vehicles or even just used to build more schools or pay for university tuition, you get something back into the economy. Certainly, the net cost to the economy is a lot less than the gross cost. It's the sort of question that economists, in principle, should be able to answer, but I myself don't have a lot of confidence in the kinds of models economists use to address such things. I'm sure there are economic studies out there that could shed some light on this issue, but don't expect miracles with regard to accurate forecasts. --raypierre]

  4. 104
    dean says:

    Hank,

    Actually i wasn’t aware of that… thanks for giving me something to study up on.

    If that’s the problem, then why the heck are we complaining about global warming? Isn’t the real problem going to be the acidification of the seas? That’s a much more tangible problem with much closer timelines. And yet, you never hear a headline about that… it’s always about how we’ll be roasting in 100 years.

    [Response: It's an issue that comes and goes in the public mind. A while back Nick Kristof of the NYT devoted a whole column to it, even referring to "the savants at RealClimate" (presumably meaning Dave Archer in this instance). But really, don't you think we can worry about more than one thing at a time? Heat is a problem, and so is acidification. I guess the attraction of acidification is that the chemistry of it is so simple it's hard to take cheap shots at. Heat is different -- the basic physics is simple, but it has a lot of fancy add-ons that give us the present IPCC uncertainty. That makes it easier for skeptics to take pot-shots at, in a way that can be made do sound convincing to the uninformed. --raypierre]

  5. 105
  6. 106
    James says:

    Re #92: [Re. #86, actually your post strikes me as irrational.]

    I should point out that in that post I was comparing fusion to fission, and most of your counter-points would most likely apply just as well to both, at least so far as we can extrapolate to a presently non-working technology. But to respond to a few points that haven’t been adequately addressed (at least in the last few threads).

    [...there is still no concensus on a long term plan for the disposal of the nuclear waste that is guaranteed to be both safe and affordable.]

    However, the primary reason there isn’t such a consensus is the anti-nuclear lobby’s insistance that any such plan is unworkable, because nuclear waste is infinitely dangerous.

    [Or to point out that this waste will be highly radioactive for many centuries.]

    Indeed, just as the ore from which the fuel was derived had been radioactive for several billion years.

    [...published costs of nuclear-generated electricity never take into account the total lifetime cost of nuclear plants, including decommissioning, maintenance and waste disposal, so one is never able to compare like with like (it’s the only form of electricity in which overall costs are ignored)]

    This is hardly true. To begin with the petty, I’ve never seen an analysis of wind or solar that included decomissioning costs, either. What will we do with all those old solar cells & windmill blades in 50 years?

    The real flaw in that argument, though, is that the price of fossil-fuel power does not include the costs of waste disposal AT ALL. Their waste is just dumped into the atmosphere, and isn’t this site all about discussing the problems that is causing? Add the costs of GW to the fossil fuel price, and see how they stack up.

    [Or to point out that if a terrorist flew a plane into a nuclear reactor it would be far more serious than 09/11.]

    How so? You might remember that it wasn’t the impact of the planes that brought down the far more fragile WTC towers. It was ultimately the weight of the towers themselves. Fly a plane into a nuclear reactor with a proper containment structure, and you just put a thin plating of aluminum on the outside.

    As to the effects of nuclear accidents in general, consider that Chernobyl was a “worse than worst case” accident, yet the Earth kept on ticking just fine: no temperature increase, no Arctic ice melt, no ocean acidification… Indeed, it seems that for most creatures life in the so-called “dead zone” is a distinct improvement on previous condidtions.

    [Response: OK, enough on nuclear. This could go on forever, but let's not do that here. The best take-home point from this thread is that the fossil fuel industry does not pay for disposal of its CO2 waste at all. Everybody ought to start thinking of CO2 from fossil fuels as on a par with nuclear waste, and figure out how to level the playing field. Let's please leave it at that. --raypierre]

  7. 107
    catman306 says:

    Isn’t the problem really just our insistence on centralized production of electrical power? If I were king, all new energy requirements would be met by small local, non fossil fuel power sources: wind, tidal, geo-thermal, methane capture, solar, etc. Excess power would be fed into the grid. Fossil fuel plants would be phased out. Small is beautiful, and can be very green. Oh, almost forgot. Conservation would become a social value again. How has wasting electricity become a symbol of wealth? Who let that happen?

  8. 108
    David B. Benson says:

    catman308 (108) — Grid stability suffers under plans like yours which rely to heavily on non-steady sources such as wind and solar. This does not mean the problem cannot be solved, just that it has not be so far.

    http://biopcat.com

    recently reported on some organization starting to build a combined power plant using wind (when available) and biomass when there is no wind. This has the distinct advantage that the power sent to the grid is stable and reliable.

  9. 109

    Regarding chapter 1′s reference to Dr. Wong’s proposal to send C02 molecules into space ,http://www.economist.com/science/displaystory.cfm?story_id=9253976, there are questions other than the energy required to emit them. He doesn’t seem to be suggesting that we use thrust to rid them of the atmosphere, but rather the use of an electromagnetic “staircase”.( Theorically it’s possible to walk out into space given a long enough staircase).

    The fly in the ointment here is that the Earth since its beginning, has contained the same elements in the same amounts, with minor losses into space due to the space program. How much will we disturb this balance by ejecting carbon and oxygen atoms out of the system? If Dr. Wong is talking about significant amounts, our planet will have a different composition than it has had in all of the years of its existence.All six thousand years!(just kidding). In addition carbon and oxygen are essential elements for life in all it’s forms. Do we really want to deplete the Earth of their presence?

  10. 110
    Hank Roberts says:

    >really want to deplete the Earth … ?

    Probably. Mars and Venus still have mostly CO2 atmospheres.
    You can look at the total amount of carbon versus the amount in the atmosphere and figure the longterm difference is trivial.

  11. 111
    Matthew Kennel says:

    “Would diverting 1% of the world’s climate research funds into this problem clarify the issues in time? I doubt it. Would devoting 10% a year to the problem be worth it? I doubt that, too, in comparison to more pressing research needs.”

    Really? We already have plenty of very secure research outlining what appears probable to happen, and it looks quite horrible. We’re not going to learn, with more research, “oops, sorry nothing will happen, Rush Limbaugh was right.”

    I don’t know about “diverting” but allocating at least 10% of the scale of this this effort to exploring emergency mitigation is prudent risk management, even knowing full well how unpleasant the schemes are likely to to be.

    Avoiding looking at it completely is, in my opinion, analogous to strident opposition to nuclear power plants, hoping for some (physically unlikely) breakthrough in completely clean energy which can substitute for nukes and coal in scale and continuity, all the while new coal plants get built.

  12. 112
    Hank Roberts says:

    Thanks Ray for your inline response above
    http://www.realclimate.org/index.php/archives/2007/10/gee-whiz-geoengineering/langswitch_lang/in#comment-62995

    I think the oceans get less discussion partly because the “so what?” problem is greater for ocean biogeochemistry — what’s going to change and how can we tell? It’s much newer as an area of study.

    Good article here, a reminder that the beasties we rely on to take CO2 and turn it into nice sedimentary limestone layers are relatively recently evolved on Earth, not much older than our own primate line in fact. Until they came along able to live out in the deep sea and make sediment worldwide, most life in the ocean was in the shallows along the edge of the continents.

    The coccolithophores may have invented the planet that invented us.

    “A coccolithophore concept for constraining the Cenozoic carbon cycle
    J. Henderiks and R. E. M. Rickaby
    Biogeosciences Discuss.: 16 Published: 19 June 2007

    Abstract. An urgent question for future climate, in light of
    increased burning of fossil fuels, is the temperature sensi-
    tivity of the climate system to atmospheric carbon dioxide
    (pCO2). To date, no direct proxy for past levels of pCO2 exists beyond the reach of the polar ice core records. We pro-
    pose a new methodology for placing a constraint on pCO2 over the Cenozoic based on the physiological plasticity of extant coccolithophores. Specifically, our premise is that the contrasting calcification tolerance of various extant species of coccolithophore to raised pCO2 reflects an “evolutionary memory” of past atmospheric composition. The different times of evolution of certain morphospecies allows an upper constraint of past pCO2 to be placed on Cenozoic timeslices.

    “Further, our hypothesis has implications for the response of
    marine calcifiers to ocean acidification. Geologically “an-
    cient” species, which have survived large changes in ocean
    chemistry, are likely more resilient to predicted acidification….

    “… our ideas have implications for the future ocean. With fossil fuel burning and a predicted decrease in pH of ∼0.3 over the next 100 years (The Royal Society, 2005), the larger species will likely have an advantage over the now prosperous E. huxleyi, as the car-
    bonate system of the ocean reverses towards the acidity of the
    past. C. pelagicus has weathered large and abrupt changes in
    conditions in the geological past, e.g. the Palaeocene-Eocene
    thermal maximum (Gibbs et al., 2006), with no apparent im-
    pact on physiology, but the adaptive strategies of newcomer
    E. huxleyi may differ significantly, potentially leading to fu-
    ture non-calcifying descendants.”

    Scary? Only if you think about it.

  13. 113
    Matt says:

    #103 David Benson: I’ve seen an estimate that $20–30 per tonne of carbon will cause (some) people to forego burning fossil fuels. But currently more than that is required to sequester carbon dioxide, although the sequestration could be subsidized.

    Terrapass is charging folks $11/ton for carbon credits. Notet that driving a hummer requires just $80 to offset a year of CO2 production (roughly 6.2 metric tons) from driving.

    A hummer driver would spend about $3000 on gas for this year of driving. So, your figure would add about $240 to the $3000 gas bill. I doubt that would cause a hummer driver to change.

    I suspect a CO2 tax of $200/ton would start to make it economically challenging for drivers, as that would put CO2 tax at about 50% of gas cost for a hummer driver.

    Note, however, that a Prius puts about 1.9T of CO2 per year, so that would be a $400 tax to the prius driver, and it’s about the same % that they would have spent on gas, too.

  14. 114
    Dan Hughes says:

    re: # 103

    Do I correctly understand the situation to be that a ‘solution’ to the problem has been proposed and yet the effectiveness of that solution is not known? We mere engineers can’t get away with those kinds of solutions. Hand-waving doesn’t work, the hard work with arithmetic has to be done.

    Let me try again, but with a harder question. What level of carbon tax is necessary to ensure that at some time in the future the concentration of CO2 in the atmosphere will stabilize? Or even more difficult, what level of carbon tax is necessary to ensure that the Global Average Temperature will not increase above that already ‘in the pipeline’?

    Can carbon taxes be implemented in such a way that they are not regressive relative to persons who can ill-afford increased costs in energy-related products and services that are essential to their health and well-being?

    Failure to address such questions on a rational and quantitative basis explains in part why Lomborg has been able to gain traction.

    Can anyone point me to quantitative studies about the effectiveness of carbon taxes on reductions in CO2 emissions?

  15. 115
    John McCormick says:

    RE # 114

    Dan, Charlie KIomanoff’s web page at http://www.carbontax.org has a wide variety of material relating to impact, effect and analysis on carbon taxes including his Congressional testimony. It is not the Wharton School page but it can link you to more of the material you want to read.

  16. 116
    Wacko says:

    I agree with Paul Dietz and Alvia Gaskill 1000% Please, this is no time to be a luddie about the geoengineering solutions! Global warming is worse than what “rational” scientists estimated.

    ’91 volcano eruption has dramatically shown the cooling effect which is mostly beneficial. Please, stop obstructing the geoengineering solutions – this is NOT the time to encouraging runaway greenhouse effect!!

    The time for the age of “niave and cautious” scientists is over. It is time for real engineers to provide social and engineering solutions (ie. ban coal, cool the earth, go to space, use bicycles, etc.). DO you really want to continue with the global warming experiment to see a dead planet or, at least, uninhabitable to the current species??

    I’m sorry for being an alarmist but I’m sick and tired of seeing a lot of naive outlook on life from this blogger.

    [Response: All you name-calling guys flinging around the "luddite" insult ought to get your history straight before parading your ignorance in public. Ned Ludd and his band of merry men were worried about the impacts of a technology that worked (all too well, from their standpoint). I, on the other hand, am worried about the impact of a technology that has unknown consequences for the environment, and which in some regards is definitely known not to work -- c.f the fact that it does nothing for ocean acidification, and also the implications of the mismatch in time scale between aerosols and CO2. --raypierre]

  17. 117
    James says:

    Re #113: [I suspect a CO2 tax of $200/ton would start to make it economically challenging for drivers...]

    It might be more effective to look at the effects of a carbon tax on electric generation. Currently fossil-fuel generation is cheaper than most non-CO2 producing types, largely because the plant operators don’t have to pay to dispose of their waste products. So then we just compute the price per ton needed to make fossil fuel generation more expensive than alternatives.

    And to change the subject back towards the thread: May I offer my own geoengineering solution? Balloons. Lots & lots of large, reflecting balloons floating around in the stratosphere, each doing its bit to increase the albedo.

    [Response: Did you mean ton C or ton CO2? Exercise for the readers: If that's per ton C, how much does the tax add to the cost of a gallon (or litre) of gasoline? How does your answer change if that number is per tonne CO2 instead? --raypierre]

  18. 118
    David B. Benson says:

    James (117) — That is quite clever, but it does not solve the problem that the oceans are becoming more acid, killing the corals, etc.

    I see no solution but to lower the CO2 concentrations to ‘basify’ the oceans.

    [Response: In fact, if geoengineering works, it will almost certainly make the problem of ocean acidification worse. If we can increase atmospheric CO2 without rich nations suffering, say, killer heat waves, then it's more likely that we'll just continue burning all the coal 'til it's gone. If the only problem is acidification of the ocean, it's made more invisible, and easier to ignore. --raypierre]

  19. 119
    Richard LaRosa says:

    1. Pump cold ocean water up from 1000 m depth and distribute it at the surface. I have a very tentative design using one cold-water pipe with two pumping plants, each bringing up 5 m3/s. We need to upwell about a million cubic meters per second to accomplish noticeable cooling of the ocean surface and the overlying atmosphere. Therefore 100,000 of these pumping stations are required. Pumping power is derived from the solar energy stored in the ocean surface by means of a heat engine that uses the temperature differential between the surface water and the upwelled water. This ocean thermal energy conversion has been under development for more than 90 years with no real success because the developers have attempted to export net power. Even in the tropical ocean, the temperature differential is so small that the heat engine can just about run itself with enough power left over to support housekeeping functions. Much of the available temperature differential is lost in the temperature drops of the evaporator and condenser heat exchangers. Attempts to export net power increase these temperature drops, leaving less temperature differential for the turbine working fluid, which lowers the engine efficiency and requires excessively large structures. The upwelling system maximizes efficiency by exporting only cold water and the nutrients that are dissolved in it. This enables phytoplankton to increase their food production. The benefits of cooling and increased primary production are spread over a large population, so the economic model provides no revenue stream to finance the development and operation of the system. So in addition to technical evaluation, we will need to improve the economics. Perhaps sufficient altruism will result from a proper appreciation of the global warming and fishery depletion threats to our collective survival. If the upwelling is done in the Caribbean, there would be economic benefit from the reduction of hurricane potential intensity, as explained in No. 3 below.

    2. Use floating solar collectors to evaporate seawater to increase orographic rainfall. Australia furnishes an ideal situation because it has a central desert which heats up by afternoon during most of the year. Heated air, which rises, is replaced by air drawn in from the coast. A mountain range on the east coast causes this ocean air to rise and expand, causing precipitation that provides fresh water to the inland slopes of the mountains. This was a fertile area used for agriculture and water supply, but it is suffering from a drought. A large area of the southeast coastal waters covered with solar evaporator rafts could increase the moisture content of this air inflow and provide needed rainfall. Of course it is not easy to maintain a uniform depth of seawater on a solar collector tray that is heaving and tilting in a rough sea. You don’t want to be heating some water only to have it slosh out of the tray when it rides a wave before it can evaporate. We will need some pumps operated by a photovoltaic panel to keep the water spread out over the evaporator tray. No battery storage is needed because the evaporator only works when the sun shines. The economic model is better here because the equipment and the benefits are concentrated near the heavily populated capital region of Australia. The development and operation could be supported through taxation.

    3. Ocean turbine arrays in the pasages between the Antilles Islands can provide electric power for utility customers and desalination plants on the islands. In addition, the turbine arrays can provide sufficient back pressure to cause some of the North and South Equatorial Current water to flow around the Antilles chain instead of entering the Caribbean Sea and passing through the Gulf of Mexico. The outflow from the Gulf is restricted by a decrease in depth and a narrow channel between the Florida coast and the Bahama Islands. The flow in this portion of the path is driven by gravity. Reduction of the flow volume would allow sea level to be lower in the Gulf of Mexico. My very approximate calculations indicate that extraction of 3 gigawatts from the current in the Antilles passages would lower the Gulf sea level by 1 cm. The proportionality between power extraction and sea level lowering might hold to greater values. In addition to pollution-free power for the Antilles Islands, the lowering of the Gulf sea level would benefit New Orleans and other cities. Furthermore the reduction of the Loop Current transport through the Gulf of Mexico would decrease its direct interference with the oil and gas operations in the Gulf, and reduce the amount of warm water accumulated inside the Loop and warm-core rings which detach from the Loop. Passing hurricanes gain strength from these warm water pockets, so this project would result in some decrease in the potential intensity of hurricanes in the Gulf, which would benefit the oil and gas industry. The economic model for this project looks encouraging.

  20. 120
    Julian Flood says:

    quote the problem that the oceans are becoming more acid, killing the corals, etc. unquote

    Well, if the oceans are not taking up CO2 as fast as expected, the acidification (actually it’s a reduction in alkalinity but let’s not quibble) rate will not proceed so quickly. Some news is good news. I was always suspicious of the study by the RS anyway: it relied on models and on studies of mixing in bays where wave action on the shore would have ensured complete equalisation of partial pressures.

    The important observation is that there is an imbalance between the ocean and the atmosphere. The CO2 in the atmosphere should be going into the water but it isn’t. Why not? The wind speed is increasing. Why is that? If it’s windier then we’d expect more wave breaking to increase mixing.

    The comments about cooling are getting a little hysterical. Might I suggest that everyone read the proposal by Latham, Salter et al about using atomised water sprays — more hygroscopic nuclei in deficient areas of the ocean should raise albedo by increasing stratocumulus cover in the boundary layer — to cool selected areas? Wind-powered, instantly switch-offable if it looks like a bad idea, the proposal works by raising the Earth’s albedo. Looks good to me — Palle’s studies would suggest to the scientifically naive that albedo drop (about 7 or 8 watts/m^2 in 20 years) is a more potent cause of warming than CO2 (2 – 3 watts/ m^2). Latham and Salter’s proposal is a good, harmless way of buying time. (I don’t know where you will find it on line — I got a copy from one of the authors.)

  21. 121
    Hank Roberts says:

    CO2 dissolving in the ocean worldwide is physical chemistry.

    Dissolved CO2 being removed from the ocean, and clouds formed over the ocean, on our time scale, looks to be mostly biology.

    http://aem.asm.org/cgi/content/abstract/73/2/554

    http://www.fysik.lu.se/eriksw/aoe2001/EOS_AOE2001_Leck.pdf

    http://linkinghub.elsevier.com/retrieve/pii/S0924796306003174

  22. 122
    Fernando Magyar says:

    Re #68,
    “As a side benefit, sea life will flourish.

    Pretty much a win-win!’

    What makes you so sure? If you read further in that very same Wiki entry you can find plenty of reason to doubt that this would work on a large scale. You know, while were at it we might try terra forming Mars too.

    http://en.wikipedia.org/wiki/Iron_fertilization#Precautionary_principle

    “Precautionary principle

    Critics argue as follows. We do not know the possible side-effects of large-scale iron fertilization. Not enough research has been done. We should not risk iron fertilization on the scale needed to affect global CO2 levels or animal populations. Creating blooms in naturally iron-poor areas of the ocean is like watering the desert: you are completely changing one type of ecosystem into another.”

  23. 123
    Chuck Booth says:

    Re # 120 Julian Flood: “…the acidification (actually it’s a reduction in alkalinity but let’s not quibble)…”

    You are technically correct, and I suppose you could call it dealkalinization. However, term acidification has long been used to describe the reduction in pH of a solution due to the addition of acid (e.g., titrating seawater, from, say, pH 8.2 to pH 7.5 by the addition of HCl or by increasing PCO2).

    Re #119 Richard LaRosa:
    I don’t suppose you have considered the impact of such a scheme on plankton and plankton-based food chains, or microbial decomposition pathways in surface waters, etc? If so, I would be curious to know what you concluded, and where this analysis has been published.

  24. 124
    James says:

    Re #118: [That is quite clever, but it does not solve the problem that the oceans are becoming more acid, killing the corals, etc.]

    I think of geoengineering as analogous to a coronary bypass: it keeps you alive for now, but if you don’t use that time to address the underlying causes – stop smoking, exercising more, etc – pretty soon you’re back for another, maybe a transplant, or maybe just dead.

    Likewise, a geoengineering “solution” just deals with the first order problems of increased temperature caused accumulated CO2 to date. Keep on increasing the CO2, and even if you don’t overwhelm the geoengineering, the second & third order problems become more important.

    Though I think an albedo reduction could help with some of those problems, too. Cool the planet a bit, and that should increase the amount of CO2 held in oceans, and increase the oceans biological productivity, which would remove some CO2.

  25. 125
    AK says:

    Rather than sulfates, why not use slaked lime? It would cool, absorb CO2, and increase the pH of the Oceans when it got there. The burning process from limestone could be backended with a CO2 capture system, which CO2 could then be combined with ammonia to produce urea and sunk in an ocean trench (surrounded by concrete or something). Like sulphates, calcium carbonate is a natural constituent of air, so there’s little risk to the biosphere.

    Richard LaRosa # 119…

    Why not a bunch of geothermal power stations along the mid-Atlantic Ridge? The warm water would naturally float to the top, no pumps or pipes needed. The nutrients would fertilize algal blooms that would not only add to CO2 uptake but to the overall sink.

    The long-term problem I see with all this is that the only really expandable place for carbon to go as we burn fossil fuels is the bottom of the ocean. This involves a real risk of eutrification, which could be a much more serious problem than a few degrees temperature rise.

    [Response: Acidification yes, but not eutrophication. CO2 is not a limiting nutrient in the Ocean. --raypierre]

  26. 126
    Ken says:

    Re #9 The problem I have with the idea that a big space program will cure our ills is the notion that somehow a lot of R&D to do that is innately more productive than a lot of other R&D. I expect the improvements in technology needed to make large scale space solar power arrays would improve the prospects for solar power here on Earth, and undercut them due to the high cost of doing it in space. We don’t need the big space program, we need the R&D. Now, if the energy transmission aspects of space power proposals could feed Central Australian solar farms to Europe or North America economically… or (more ironically) Middle East solar farms…

    On climate engineering – it deserves looking into but the confidence levels re indirect as well as direct consequences need to be very high.

  27. 127
    Richard LaRosa says:

    Re:123 Chuck Booth. Upwelling cold deep water brings up the macro nutrients (nitrate and phosphate ions) and micronutrients (iron) that are abundantly dissolved in the deep water. These are needed by the phytoplankton to replace the nutrients that they use up in the surface water. I have some calculations of the additional biomass that will be created by upwelling a million cubic meters/sec, but I need to study the books that I have bought to be sure of my estimates. In particular, since sufficient ocean thermal energy (to run the heat engine) is available only in the tropics, the calculations must be specifically for the tropical ocean. This will involve species different from those involved in food chains in the temperate regions where natural upwelling brings up the nutrients. I hope to get some answers that can be published.

  28. 128
    Richard LaRosa says:

    Re:125 AK, I’m trying to bring up cold water for surface cooling. I know it has nutrients dissolved in it. Don’t want warm water and don’t know what’s coming from the Mid-Atlantic Ridge.

  29. 129
    Richard LaRosa says:

    Re#125, we want cold water for surface cooling. It’s heavy and won’t float to the top. This takes power, about 1.8 megawatt per pumping station. 100,000 stations take 180 gigawatts, supplied by the sunshine that heats the surface water.

  30. 130
    Hank Roberts says:

    http://www.insidebayarea.com/argus/localnews/ci_7311055

    ——excerpt follows, see link for full story ——-

    Foster City-based Planktos Inc. has invested $2 million in a controversial effort to spread as much as 100 tons of pulverized iron across a vast swath of ocean to stimulate the growth of carbon dioxide-gobbling phytoplankton. …

    Planktos will sprinkle iron dust around a 100 kilometer by 100 kilometer zone of open ocean and Coleman predicts the plankton community will mature within six months.

    He is confident Planktos can have a certified product to market within 12 to 18 months. The entire effort is expected to cost $2 million.

    Once the company has received certification from U.S. and international officials, Planktos will be able to sell the carbon credits more cheaply than its competitors. Prices currently average $5 to $10 a ton. ….

    —- end excerpt ——-

  31. 131
    Bob Schmitz says:

    Re 130: This Planktos story is a good illustration of the risks of geo-engineering! They proposed to dump iron near the Galapagos archipelago of all places. Fortunately I read in the link provided that this bet is off. But it does illustrate that even smart engineers forget to take into account ‘trivia’ like doing your initial experiments near a biological hotspot. If enterprises like this one manage to find investment capital, it is likely that some poor 3rd world country will give out a concession, and potential damage will not be sufficiently scrutinized. If corruption would come into play, things could turn out even worse.

  32. 132
    Hank Roberts says:

    Here’s why biofuel isn’t enough of an answer, well stated:
    http://littlebloginthebigwoods.blogspot.com/2007/10/fuelish-fantasies.html

  33. 133
    Alvia Gaskill says:

    RE: 73 Going Public

    There’s an argument to be made in not sugar coating geoengineering as OTS technologies. But as I’ve pointed out before, the more typical response is to exaggerate the negative consequences, often without a sound basis for doing so.

    The other response is to attempt to censor the discussion, although with the recent upwelling of symposia (AGU in December), high-level meetings (Boston) and journal publications (Phil. Trans Royal Soc.), it seems unlikely that discussion time is over.

    The issue of censorship comes up in a recent issue of Science.

    http://www.sciencemag.org/cgi/content/full/318/5850/551

    GLOBAL CHANGE:
    Tinkering With the Climate to Get Hearing at Harvard Meeting
    Eli Kintisch
    Should scientists and engineers seriously consider large-scale
    alterations of the climate to stave off the worst effects of global
    warming? Several dozen top U.S. climate scientists will explore that
    controversial question next month in a 2-day invitation-only workshop
    at Harvard University designed to explore whether direct interventions
    might be needed to supplement efforts to reduce greenhouse gas
    emissions.

    Curbing greenhouse warming manually, so to speak, could offer a more
    immediate and possibly simpler solution to climate change than the
    massive overhaul of energy systems that would be needed to cut global
    greenhouse gas emissions. Ideas include removing CO2 from the
    atmosphere by forcing air through absorbers or stimulating plankton
    growth, and shading the planet with aerosols. But many prominent
    climate scientists have been leery of even discussing such
    possibilities for fear that they could provide policymakers with an
    excuse not to cut carbon emissions, or that the technology comes with
    serious side effects. As a result, says Harvard geochemist Daniel
    Schrag, who is organizing the meeting, discussions have occurred
    mostly among advocates. “I wanted to get the mainstream climate
    community … to look closely at this thing,” he says.

    The 8 to 9 November meeting will include climate heavyweights such as
    James Hansen of NASA, Kerry Emanuel of the Massachusetts Institute of
    Technology in Cambridge, and Mark Cane of Columbia University. Its
    focus will be on ways to lower the atmosphere’s temperature, including
    releasing massive amounts of sulfates into the atmosphere to mimic the
    natural cooling effects of volcanic eruptions. Such an approach was
    publicized last year by Nobelist Paul Crutzen, an atmospheric chemist
    at the Max Planck Institute for Chemistry in Mainz, Germany (Science,
    20 October 2006, p. 401).

    Scientists pondering geoengineering ideas argue that such cooling
    schemes could be hard to control and wouldn’t address the
    acidification of the oceans caused by CO2. Others worry that any
    discussion of the topic will undermine political momentum to cut
    greenhouse gas emissions. These include atmospheric scientist
    Elisabeth Moyer, who before leaving Harvard for the University of
    Chicago told Schrag that the conference should be held off campus or
    without publicity. “I had concerns about lending the conference the
    prestige of the Harvard name. … The conference can be viewed as an
    endorsement [of geoengineering],” she says. Even so, Moyer thinks that
    “it is critical to discuss the idea.”
    Hansen says better forest practices, advanced agriculture techniques,
    and geologic carbon sequestration could supplement the real emission
    cuts required to stave off dangerous climate change and avoid the need
    for geoengineering efforts. He hopes to spread that message at the
    meeting. “The potential for stabilizing climate is more than
    realized,” he says. But he agrees with Schrag that geoengineering
    should still be explored, as future policymakers might seek to do it
    whether or not scientists understand it. “I don’t think scientists
    should shy away” from the topic, he says.

    The fact that the meeting is taking place at all marks a new phase of
    urgency among climate scientists, says modeler Ken Caldeira of the
    Carnegie Institution of Washington in Stanford, California. In a 1998
    paper, Caldeira called the aerosol approach “a promising strategy,”
    although he argued that emissions cuts remain “the most prudent”
    course of action. “A decade later, a bunch of people are coming to the
    same point,” says Caldeira.

    Note the response of Elisabeth Moyer who is quoted as saying she thought the meetings should be held off campus or without publicity. Perhaps in an underground parking garage and Bob Woodward can take notes?

    The meeting is billed as a chance for all kinds of views to be expressed, not just those of supporters of geo. Good luck and maybe bring a taser just in case.

    A similar meeting was held almost a year ago at Moffet Field and was treated by some of the media like a war was being planned. BTW, where is the report on that meeting?

    The second example concerns the response from those would be Woodwards, the bloggers and is a virtual tutorial on exaggeration. This one comes by way of the folks operating the grist mill.

    http://gristmill.grist.org/story/2007/10/28/17223/112

    The mill workers apparently need some time off. They’ve been working way too hard. Working conditions must be Medieval at best.

    The Grist Man has imagined a conspiracy that would dwarf anything Scully and Muldar ever had to contend with. NRDC in bed with Exxon and BP. And Stanford and Princeton too! Oh my!

    He lumps all the geo ideas together, from aerosols to moving the Earth out of its orbit.

    But the biggest geo threat is carbon capture and sequestration, which he sees as the real get out of jail free card for big oil, big coal, big natural gas, big auto and any other biggies I may have left out. He thinks this will serve as a distraction for the funding and attention needed to develop renewable energy.

    This is kind of ironic, since the term geoengineering was originally coined to describe ocean disposal of carbon dioxide from power plants. He classifies the Stanford/NRDC work as geo, but the convention has been to treat carbon capture as a separate approach and their web site does so. Although geo is listed as one of the research areas funded by the Stanford grant program, to my knowledge, no work has been done.

    Grist Man correctly points out some of the potential problems with carbon capture, from leaking back into the atmosphere to how the technology will get transferred to China and India, implying they won’t be smart enough to use it properly.

    The Conspiracy Bus also veers off the NJ Turnpike and down a steep embankment when he implies that Princeton is conducting significant geo research at the behest of BP. The only geo research I found concerns some modeling of the efficiency of iron fertilization that was inconclusive. They are, however, carrying out studies related to carbon capture and sequestration.

    So by blurring the distinction between geoengineering and carbon capture, this blogger attempts to delegitimize any effort to continue to use fossil fuels and at the expense of geoengineering. As if it doesn’t get enough bad publicity already.

  34. 134
    AK says:

    Re 128, 129 Richard LaRosa…

    Sorry, I thought you were trying to fertilize algae with nutrient-rich bottom water. But I’m curious, if you bring cold, saline bottom water to the surface without warming it, what’s keeping it from turning around and floating back down?

    Some other thoughts…

    How about towing some icebergs from the polar regions out into the tropical doldrums? They’d not only cool the top water, but lighten it by diluting it. Not only that, but they might produce enough fog to increase the albedo by a significant amount.

    Speaking of albedo, how about a bunch of aluminized foam plastic “popcorn”. Just set it floating. One thing about that, if the effect turned out wrong, you could probably just gather it up like you would an oil spill.

    Or you could use pumice, real or artificial.

  35. 135
    John L. McCormick says:

    Some thoughts about geoengineering ideas……they are endless and limited only by our imagination; the most far-out can qualify for entry into the discussion if the sponsor cares to offer it.

    Good thing we are not discussing this in a legislative session or policy-formation Cabinet meeting.

    The foregoing commentary is evidence the world community will never get a collective handle on geoengineering because the ideas appear not much more than throwing paper in the air and hoping the ones that land on the x mark will actually be feasible. Humans are now more judicious when it comes to unilateral action on which the World Court can render a judgement.

  36. 136
    Richard LaRosa says:

    Re#134 AK,as you point out, cold deep water brought to the surface will sink unless it is distributed widely enough to mix with the surface water and reach an equilibrium temperature that will keep it near the top. The only method I have found so far is to discharge the cold water through a long perforated hose. This adds to the pumping power requirement. If the pumping plant is in a steady ocean surface current, the discharge hose can trail downstream. In a shifting ocean current the long hose can be a problem, especially if the current reverses, as in a tidal flow. I wish I could find a better way to spread the cold water at the surface.

  37. 137
    Walt Bennett says:

    All of this serious discussion of geo-engineering projects is enough to make me scared of you.

    I do not believe that geo-engineering is a fit topic for scientists.

    Engineers, maybe, but then that’s what they do.

    Scientists figure out how things work. If you like fancy ideas, write a novel.

  38. 138
    AK says:

    Re #135…

    IMO the way a discussion like this one could be most valuable is as a search for valuable, out-of-the-box ideas. It seems to me that a preliminary feasibility screen could be applied to every idea that comes up, rather than allowing them to depend on how hard a “sponsor” wants to push them.

    The more “far-out” an idea is, the less likely it is to have already been considered by experts and deemed unfeasible. This means the possibility always exists that an idea that comes up in a discussion like this might turn out to be the “magic bullet” that could cheaply and effectively solve the immediate “problem” of excess CO2.

    Personally I’m not at all sanguine about the existing climate models, and the possibility of a “tipping point” waiting unseen right ahead should not be neglected. This doesn’t (IMO) justify “turning out the lights”, but if something could be implemented to reduce CO2 to 280 PPM in a decade or so, and the side effects seemed predictable and containable, it should probably be considered.

    Along this line…

    An idea that I came up with a little while ago, that I’m coming to like more and more as I think about it, is to genetically engineer a new version of peat moss to be very fast-growing and tolerate brackish water and tropical climates. For containment, it could be designed without some essential parts of the reproductive apparatus (vegetative growth only) and made vulnerable to certain poisons or dependent on certain trace materials.

    Peat bogs generally contain their carbon until somebody digs them up, so given some minimal low-level hydrological engineering large area carbon sinks could be set up quickly, and if they work, the process could be expanded rapidly.

    I would guess the current level of knowledge of genetic engineering is up to such a project.

  39. 139
    Hank Roberts says:

    > peat moss
    The mass of the hypothetical peat moss would end up about equivalent to the mass of coal and oil burned, and the volume would be much greater. I suspect there are problems with the numbers involved there. The genetic engineering needed to make anything that complicated, let alone that manageable, is far beyond the current state of that art.

    Hey, why not invent a form of calcite-shell-forming plankton that would build floating cities instead?

  40. 140
    Richard LaRosa says:

    Re#137 Walt Bennett, my work is based on sound science and engineering. I have worked on my ideas for some time and have attempted to quantify them. People should examine them and ask detailed critical questions rather than dismiss them out of fear or ignorance.

  41. 141
    James says:

    Re #139: [The mass of the hypothetical peat moss would end up about equivalent to the mass of coal and oil burned...]

    And what’s to stop people from burning that peat as a source of energy?

    [Hey, why not invent a form of calcite-shell-forming plankton that would build floating cities instead?]

    I think it’s already been done, with the floating cities conveniently anchored, too. Coral :-)

  42. 142
    Hank Roberts says:

    > burning that peat
    If you want to _remove_ the excess carbon dioxide, that’s out.

  43. 143
    Walt Bennett says:

    Re: #140,

    In my layman’s opinion it is sheer hubris to believe we can safely geo-engineer any aspect of the environment. As I stated previously, our understanding of the atmosphere is so primitive that we cannot meaningfully anticipate the consequences of changing a single input.

    From this lofty perch we propose that we can leap off the cliff and teach ourselves to fly?

    A little humility toward the grand complexity of nature would seem to be in order.

    I do not dismiss the fact that work has been put in on this. Work gets put in on all kinds of ideas. Think away! No harm in thinking about things, right? Conducting some experiments and so forth.

    How you envision translating a little bit of knowledge into an action as definitive as an attempt to change global climate is staggering.

    There is a very serious skeptical argument to be made, and perhaps I am not the one to make it, though I have tried.

    Bottom line: the only way to know if ideas this large work, is to try them. Then you are stuck with the consequences, good or bad.

    The only approach that makes sense to me is to identify human activities that already influence the climate, and to moderate those activities. As the flower children might have said: to get in better harmony with nature.

  44. 144
    John L. McCormick says:

    Walt, I think you are doing just fine. Serious skeptical arguments might also miss the details that apparently escaped the ethanol industry and perhaps will doom the cellulosic enthanol industry.

    Take a moment to read (link below) the objective appraisal of the liklihood of cellulosic ethanol becoming commercial anytime soon, or ever, they will do themseles a large favor by not investing a dime in that dead end idea.

    Wish we had thought a bit more of the whole system and how pieces must fit when the Democratic candidates dished up corn ethanol to get the farm vote. We are really not a clever specie; we just think we are.

    And is the ethanol craze a varient of geo-engineering?

    http://littlebloginthebigwoods.blogspot.com/ 2007/ 10/fuelish-fantasies.html

  45. 145
    John L. McCormick says:

    RE# 144

    Walt, try this link, the pervious one was broken.

    http://littlebloginthebigwoods.blogspot.com/2007/10/fuelish-fantasies.html

  46. 146
    Ray Ladbury says:

    It is interesting to me that the remediation approaches currently being considered for climate change can be classified into two categories:
    1)Geoengineering–approaches ranging from fertilizing the oceans to detonation of many nukes
    2)Econo-engineering (a term I just coined)–which looks at policy/fiscal changes ranging from cap and trade, carbon taxes, etc. to forcing everybody to live like the Amish.

    It is also interesting that those who understand the science are largely horrified by the geoengineering approaches, while those who are of a more business/economy bent (and are past the denial stage) are horrified by the econo-engineering approaches. In part, this may be due to the natural human tendency to attribute any adverse consequence to SEP (somebody else’s problem). However, I think it also reflects our level of comfort with our own state of knowledge about our specialties. Those who understand climate and geo/eco-sciences know we are altering the climate, since this is a very robust conclusion. We are much less comfortable with making predictions for what the consequences will be, and we have no comfort at all with our ability to predict the consequences of geoengineering efforts for a system as complicated as the global ecosystem.
    Similarly, I think most economists are comfortable with the conclusion that markets tend to work efficiently. They also know that most well meaning efforts to “improve” markets do more harm than good–in part because there is always somebody who wil try to work a scam on the market intervention.

    So we have the prospect of climate remediation playing havoc with the ecosystem or with the economy, and we don’t have sufficient understanding of either to fully anticipate the unintended consequences. And at the same time, we know that if we do nothing, the results will likely be severe for both the ecosystem and the economy. I can see why folks are a little nervous.

  47. 147
    Alvia Gaskill says:

    RE: 143 If we can’t understand the impact of changing inputs, then we better not attempt to reduce emissions, right?

    The scale and duration of any geoengineering experiment would have to be determined in advance so as to maximize the amount of knowledge to be gained, while limiting any negative impacts.

    Release 50 tons of H2S in the upper stratosphere once and there won’t be a measureable effect of any kind. Do 5000 tons a day for 6 months and there probably will. Likewise with proposals to increase clouds, redirect ocean currents, etc.

    Some have pointed out correctly that because natural variations or at least those that we are now calling natural can be confused with impacts from geoengineering, separating the natural from the man-made may be difficult.

    Pinatubo at one time was blamed for the midwest flooding in 1993 and a corresponding drought in the Sahel. However, there was flooding this year also in the midwest, although not as great as in 1993, obviously not due to a volcano. And there are droughts in Africa all the time that are expected to worsen due to global warming, irrespective of any geoengineering tests.

    At what scale would an aerosol test or program cause regional or global weather changes? Some of this can probably be estimated using modeling and data from previous volcanic eruptions, but the truth is, we will just have to perform the experiments in order to find out.

    The good news is that such experiments can probably be terminated after a few weeks or months, well before any long term changes have occurred. My desert cover plan involved a series of stages beginning with modeling and proceeding to progressively larger field trials. The same approach would likely be followed for any geoengineering project.

    I must emphasize that I was never in favor of doing field trials without first exhausting what we could learn from modeling and other implementation related studies. Where I differ from Ken Caldeira, Mike MacCracken, Paul Crutzen and various others is that I believe that the modeling and implementation work needs to be fast tracked and that this be treated as a “right now” emergency instead of one some unknown number of decades hence.

    To convince me otherwise, someone is going to have to show me with some certainty how real progress is going to be made on reducing emissions. To date, I am unconvinced.

    If we attempt to study this issue to death because we really don’t want to do it in the first place, we may wind up studying our own death and everybody else’s.

    RE: 137 Should “scientists” stay out of geoengineering and leave it to the “engineers.” Well, I got some news for you. There are no scientists or engineers. There are people who carry out studies in fields that involve these disciplines, but very few people are so limited in their knowledge base that they can’t contribute outside their field.

    Why do you think Google is hiring all those people who aren’t computer programmers or is it software “engineers” they call themselves these days to assist in organizing all the information in the world and placing ads next to it?

    To successfully develop geoengineering technologies is going to require the efforts of people from a wide range of backgrounds, just like the IPCC reports that aren’t all prepared by climate modelers.

    The basic science has to be addressed first, however, since it is that which drives the technology. Without Einstein’s E = mc2 there is no atomic bomb or nuclear power plant.

    So the scientist, whether a chemist or physicist by education or experience has a lot to contribute to the identification and development of geoengineering technologies. He just can’t do it all by himself.

  48. 148
    James says:

    Re #143: [In my layman’s opinion it is sheer hubris to believe we can safely geo-engineer any aspect of the environment.]

    Unfortunately we have been engaged in an unintentional geoengineering experiment: adding large amounts of CO2 to a planet’s atmosphere. The jury’s still out on whether we can do this safely, but the evidence to date is not looking good.

    We’ll see what happens, but it seems only prudent to think about what might be done in case the experiment starts to burn down the lab :-)

  49. 149
    AK says:

    Re: #139

    peat moss

    The mass of the hypothetical peat moss would end up about equivalent to the mass of coal and oil burned, and the volume would be much greater. I suspect there are problems with the numbers involved there. The genetic engineering needed to make anything that complicated, let alone that manageable, is far beyond the current state of that art.

    You’d need some quite extensive, and deep, peat bogs. However, AFAIK the amount of anthropogenic CO2 in the air is only a fraction of that created by burning all that oil and coal. IMO the best thing to do with it would be to gather it up periodically, wrap it in something waterproof, and drop it in a trench or alluvial fan.

    My back-of-the-envelope calculation says that removing 100 PPM from 5×10^8 Km^2 surface at 10 tons/meter^2 at 10% density (the rest being water) would take up 5000 Km^3. At 10 meters thickness that’s half a million Km^2, which is a pretty big deal. At 100 Meters thickness, it’s 50,000 Km^2, which is a manageable area, but growing that depth of peat bog might take more sophisticated hydrologic engineering.

    As for genetic engineering, I doubt “dropping out” a few genes necessary for the reproductive process would be difficult, and a little research a while back showed me that the regulation process of RuBisCo is already being studied in C4 grasses. Obviously, similar studies would have to be made of sphagnum, and perhaps a gene for RuBisCo and part of the regulatory process would have to be spliced in from some other plant.

    I’ll take your word for it that this sort of thing is beyond current technology, but I wonder how long it would stay that way, especially if there were a strong focus on it. The big advantage of this plan (IMO) is that it doesn’t really involve tinkering with the global system, just something not much bigger than agriculture.

  50. 150
    Walt Bennett says:

    Re: #147,

    [RE: 143 If we can’t understand the impact of changing inputs, then we better not attempt to reduce emissions, right?]

    That came off a bit glib, and it also inverts my point. “Reducing emissions” is not an action, it is a reaction to “Increasing emissions and learning that they harm the environment”.


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