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  1. Yes, some of those geo-engineering recommendations scare me as well. However, the one topic that does not seem to have been covered as dramatically as it appears it should is the subject of Biochar and its ability to ‘sequester’ carbon into the soil in HUGE volumes, as well as the other benefits of preparing the soil for post-oil agriculture and providing some carbon-negative liquid fuel energy from agriwaste. (Biochar is not food Vs fuel).

    Some have claimed that an large enough agricultural area, possibly the size of France, could store all human Co2 emissions. (See my blog page here for a variety of links).

    Tim Flannery is at this year’s International Biochar Initiative conference, so I’m hoping to hear a report from him as to volumes, but written clearly for non-techies like myself.

    Cheers, and keep up the great work!

    Comment by David Lankshear — 20 Aug 2008 @ 7:38 AM

  2. Prof Barry Brook has a couple of good posts on this topic at his new blog It is worth a look. Another quality site backed by science like Real Climate.

    Comment by plover — 20 Aug 2008 @ 8:02 AM

  3. The geo-engineering experiment that we entered into upon the advent of the Industrial Revolution has yielded poor results, and it has been determined that the outcome will not be conducive to most life on Earth as we know it today. So why should we be insane enough to even consider entering into a whole new experiment to act as a band-aid for the failed initial attempt. There is no rhyme where there is no reason.

    Comment by Ron Crouch — 20 Aug 2008 @ 8:46 AM

  4. Geo-engineering is akin to Central Banks trying to keep the economy on track; it is to the scientific community what interest rates are to Central Banks; tools whose effects are mostly uncertain. And once you start interfering with a system that was previously self-regulated, it is virtually impossible to look back.

    Most Central Bank decisions are arguably not preventative but reactive e.g. in response to the current credit crunch, while the Fed – and its peers outside the US – are being granted increasingly more powers to regulate the financial markets.

    Detractors of Central Bank intervention even argue that they only make matters worse by focusing on short-term considerations and thereby create bubbles that would have never existed otherwise, for example by keeping the cost of credit artificially low.

    Furthermore, Central Banks can only intervene within the boundaries of their hosting nations: the US for the Fed, the Eurozone for the ECB… and unless they act in tandem with each other, or at least take a global view of the economy, they are bound to fail to have a positive impact. Similarly, how do we intend to settle the disagreements between countries that benefit from global warming and those who don’t? Whose decision will prevail?

    For those of us working in financial markets, the limitations and drawbacks of intervention should be obvious. I worry that geo-engineering is adding another layer of complexity to our societies, thereby making it more vulnerable to “system failures” (leading to runaway climatic change) and to human inability to foresee the consequences of their acts.

    But do we still have a choice not to intervene? Let’s remember that the Fed was born of panic, crises and crashes…

    Comment by Fabien Bulabois — 20 Aug 2008 @ 9:04 AM

  5. We need to distinguish between geo-engineering methods that only “mask” the rising CO2, by increasing the planetary albedo (sulfates, etc.) versus those that actually remove CO2.

    Even disregarding the concerns about effectiveness raised in this thread, sulfates and other albedo-based geoengineering approaches won’t prevent changes to ocean chemistry (“ocean acidification”) or other non-radiative impacts of a higher-CO2 atmosphere.

    Comment by J — 20 Aug 2008 @ 9:12 AM

  6. LOL Gavin.

    In case any of the rest of you missed the timeliness of the reference you should Google “methadone death” in news.

    (recatcha fortunecookie: comfort ping)

    [Response: Actually that’s just a coincidence. But possibly salutary. – gavin]

    Comment by Arch Stanton — 20 Aug 2008 @ 9:18 AM

  7. W. Edwards Deming, the great statistician and management theorist, showed that a lack of understanding of a system led invariably to its tweaking. Geo-engineering is the tweaking of the system rit-large. The system is our planet’s biosphere, and tweaking it may very well lead, as Deming warned, to sub-optimization, decay, and the eventual destruction of the system. The fact that such ideas as geo-engineering are being given such serious discussion is troubling.

    Comment by Andrew — 20 Aug 2008 @ 9:22 AM

  8. Yet another problem with geoengineering is that nobody will agree on what the “optimum” climate conditions are. Let’s say that India would (on the whole) benefit from Climate X while China would benefit more from Climate Y. We could see different groups each adopting their own geoengineering strategies (or working to sabotage their opponents’) in a struggle for control of the climate system.

    Likewise, once you start tampering with the climate, people will hold you responsible for every warm/cold/wet/dry anomaly. We already see this with arguments over whether hurricanes/fires/etc are affected by our “accidental” geoengineering experiment of pumping CO2 into the atmosphere. When you tell the rest of the world that you’re going to use sulfates to “set” the climate of the earth as if it were some kind of thermostat, expect to get the blame for every piece of bad weather anywhere (and no credit for good weather….)

    Comment by J — 20 Aug 2008 @ 9:22 AM

  9. J–wrt the optimum climate. In the absense of geopolitical concerns, we could define optimum climate as that which maximizes sustainable production of food from agriculture, aquaculture, etc., could we not? If that is the case, given that the infrastructure of agriculture all developed at a time when climate and CO2 were pretty stable (the past 10000 years), the preindustrial climate would likely be considered “optimum”.

    Comment by Ray Ladbury — 20 Aug 2008 @ 9:41 AM

  10. Ray,
    I don’t think your definition will work. First, what the maximum sustainable food production is, depends on what you want to produce (e.g., how much meat), and what technologies you have available. Second, there are other issues to consider – like disease, and rates of species extinction.

    Comment by Nick Gotts — 20 Aug 2008 @ 10:09 AM

  11. We not only need to stop all anthropogenic emissions of CO2 and methane as quickly as possible — which means ending all use of fossil fuels, ending deforestation, and ending “industrial” agriculture, especially animal agriculture — but we also need to reduce the existing anthropogenic excess of atmospheric CO2, bringing it back down to pre-industrial levels. The best way to accomplish this is through large-scale reforestation and organic agriculture techniques that sequester carbon in the soil. These approaches are not “geo-engineering”, which suggests imposing some kind of human control on the Earth system to maintain it in whatever state we think will suit us. Rather, these approaches are all about changing the way that we humans “make a living”, so as to bring ourselves back into sustainable balance with the rest of the biosphere and live within the carrying capacity of the Earth.

    Comment by SecularAnimist — 20 Aug 2008 @ 10:28 AM

  12. Notably, how does anyone balance temperature changes that effect ice sheets versus the failure of the Indian Monsoon?

    effect => affect

    Comment by llewelly — 20 Aug 2008 @ 10:36 AM

  13. Ray:

    Nice idea, but that sounds very speculative to me. I’m not sure there is a single distinct climate pattern that “maximizes sustainable production of food from agriculture, aquaculture, etc.” without making assumptions about things like the amount of meat in the diet, etc.

    More importantly there’s no sense in talking about this “[i]n the absense of geopolitical concerns”. It seems obvious to me that different countries would benefit more from different potential climate modifications. If we go down that road, no country is going to accept the idea that its own agriculture should suffer for the cause of maximizing productivity somewhere else.

    I agree that the best solution is to aim for as little anthropogenic tampering with the climate as possible. In my case, though, that conclusion comes from emphasizing the political and physical problems with geoengineering, not from an argument that a preindustrial climate would maximize productivity.

    Comment by J — 20 Aug 2008 @ 10:52 AM

  14. Andrew writes: The system is our planet’s biosphere, and tweaking it may very well lead, as Deming warned, to sub-optimization, decay, and the eventual destruction of the system.

    I hate to break it to you, but we’re already way beyond “tweaking.” We’re well down the curves of sub-optimization and decay, and the wholesale destruction of the biosphere is clearly visible on the near horizon.

    Add warming and ocean acidification into the mix, and it’s hard to see how even the smallest parts of the biosphere will survive to the end of this century.

    [Response: Let’s not get carried away. Some parts of the biosphere survived Snowball Earth and the KT impact event – they will survive us. – gavin]

    Comment by Jim Galasyn — 20 Aug 2008 @ 11:00 AM

  15. Geoengineering is no bowl of cherries, but if Robock wants to avoid Pat Michaels’ fate, Figure 1 will need extension into the post-fossil fuel era.

    Picking a modeling interval where switching off the aerosol shade coincides with peak oil and coal CO2 forcing is a choice guaranteed to produce an apocalyptic temperature snap-back.

    This amounts to sharp analytical practice, because Crutzen’s stated aim is getting us past the CO2 production peak, not throwing us off the top of it.

    Comment by Russell Seitz — 20 Aug 2008 @ 11:26 AM

  16. Nick, I would say that disease and species extinction would be considered as part of the adjective sustainable, and with 9 billion folks on the way, meat will be one helluva luxury under the best case scenario. My point is that agricultural production–on which all of civilization depends–is most likely to be optimal and sustainable for the conditions under which it evolved, that is if we don’t muck with the climate too much.

    Of course, the other thing about “geoengineering solutions” is that in addition to the undesirable side effects, the timescales on which they act are very much shorter than that of CO2. As such, it’s hard to view them as anything other than an act of desperation to buy more time.

    Comment by Ray Ladbury — 20 Aug 2008 @ 11:43 AM

  17. Instead of prevailing policies, with interest I follow when capturing CO2 from the air will be the lowest-cost system.

    Please see

    Stolaroff, Joshuah K., 2006. Capturing CO2 from air: a feasibility assessment. Thesis, Carnegie Mellon University, August 17, 2006, online

    “…We find that the cost of capturing CO2 with the complete system would fall between 80 and 250 $/t-CO2, and improvements are suggested which reduce the upper-bound cost to 130 $/t-CO2. Even at the high calculated cost, air capture has implications for climate policy, however dedicated engineering and technological innovation have potential to produce much lower-cost systems.“

    [Response: Marvellous. Does this mean you support a carbon tax of up to $250 ton-CO2 to pay for it? – gavin]

    Comment by Timo Hämeranta — 20 Aug 2008 @ 11:49 AM

  18. I wonder how far the analogy can be pushed. Methadone, for example, is far more addictive than heroin.

    Comment by Jeffrey Davis — 20 Aug 2008 @ 11:55 AM

  19. Re: #11 SecularAnimist

    ….wouldn’t the increase of certain types of vegatative biota also result in additional increases in CH4? If this is the case (which apparently it is), going ‘green’ may not be the answer.

    Comment by Rando — 20 Aug 2008 @ 12:03 PM

  20. Geoengineering of the atmosphere is suicidal. What if we got started and had some cooling. I claim with virtual certainty that the same political slimemolds that promoted BAU even in the face of rising temps will leap in glee at the prospect that we Solved The Problem.

    More mining, more pumping, more carbon releases. No alternative energy, no conservation, no carbon emission reductions. Losers before we even got started.

    We will have bought our fossil fuel consumption “right” at the cost of eternally geoengineering an entire PLANET. What will be the cost of this in real dollars? What political cost? And what treaty will bind all nations to this program for all eternity? What wars will erupt if someone decides not to play along? Which large nation will be the first to hold the rest of the world at ransom because they could destroy the planet by not supporting the geoengineering objectives?

    Then 30 years later when the budget for geoengineering runs out (it will) or the treaties break down (as they must) and the aerosols or shiny metal flecks or whatever leach out of the atmosphere… there is all that carbon, ready to murder us in our sleep.

    But people will want it, oh yes. They will hang on high any politician that doesn’t give them their energy binky. Just give them a pill they can take for this little “problem”, even if it is forever. But don’t ask them to change anything or look at how they live. They have a right to be the way they want to be, granted by God.

    I have faith that geoengineering will never take off. We don’t have the budget for it, we can’t craft the treaties in time, and the scale of the effort dwarfs individual nations. So, DOA and just as well. What will likely happen however is that the fossil energy industry will trot out geoengineering sooth-sayers to calm the masses and give politicians an excuse to hold off actually doing anything useful. We will have a pill for you! Just wait. Just a little longer… oops.

    — act fast decide fast —

    Comment by cat black — 20 Aug 2008 @ 12:27 PM

  21. I posted this over at Tamino’s site a couple days ago but his backache seems to have captured all the other bloggers attention. Then today I come here and see this entry and thought “how relevant”.

    Recent studies have shown a doubling of stratospheric water vapour, likely from increasing atmospheric heights due to global warming, overshooting thunderstorm tops from stronger tropical cyclones and mesoscale convective systems etc…

    Since sulfur dioxide reacts with water vapour in the stratosphere to form sulfuric acid droplets, would SO2 flux from volcanic activity cause even greater swings in global temperatures?

    I would assume that the increase in stratospheric water vapour would make for a thicker vail of sulfuric acid given a large volcanic eruption. Even a smaller eruption that manages to have an eruptive plume that reaches the stratosphere could very well have greater implications on global temperatures if there’s more water vapour for SO2 to react with.

    Perhaps in the future a large volcanic eruption (VEI 5-6 or greater) may cause 1-2°C swings in global temperatures as they rise further as we go from enhanced greenhouse effect to enhanced reductions in insolation from thicker sulfuric acid vails.

    I bring this up due to the eruption of the Kasatochi volcano, which had an estimated 1.5Tg flux of SO2. This is only around 10% of the SO2 flux from Pinatubo but it got me thinking…

    Anyone with any input on this I’d like to hear from.

    Comment by Tom Woods — 20 Aug 2008 @ 12:28 PM

  22. Methadone is a pretty good metaphor — kind of like saccharine, sugarless sodas, and decaf coffee. Not really facing the problem.

    Geoengineering works to enable and prolong high-carbon usage.
    Politicians will seize the panacea to demonstrate problem solving attention.
    Public mollified.
    Essential problem remains.

    Substitutes will do little to change the underlying habit and have unforeseen complications.

    Comment by Richard Pauli — 20 Aug 2008 @ 1:11 PM

  23. The public (including politicians and nontechnical managers) seem to have a taste for technical quick fixes to AGW, without regard for their feasibility or effectiveness. (e.g., “use radio reflective material on the polar ice caps”) Consider for example the discovery Channel program where they intend to “test” a group of such fixes and the interest in such fixes in some of the “fantasy futures” polls such as the one run by abc7news.

    This makes me wonder how firm a grasp on reality our society has given the recent poll that “Many think God’s intervention can revive the dying” (

    I am not sure that our society differentiates between, “God will save us” and “new technology that I do not understand will save us.” I think we should reread the story of Noah in the Bible. The real lessons are: 1) God does not save people. 2) The people that survive are the ones that understand technology (i.e., ark building), have self discipline, and work very hard. God did not give Noah an easy solution. Nothing about the AGW problem is going to be easy. This is not a lesson that people want to hear.

    Any solution to AGW will be technically/ logistcally complex and will require sacrifice. That will be a hard sell. Finding solutions to AGW is easy. Selling those solutions to the public is hard. Thus, we keep looking for solutions that are easier to sell to the public, rather than aggressively implementing solutions that we already know would work.

    Comment by Aaron Lewis — 20 Aug 2008 @ 1:17 PM

  24. Creating more acid rain, which comes from SO2 (also from NOx from cars), is no solution at all — acid rain destroys forests, lakes, soil, buildings, and lungs. It has tremendous costs and tolls.

    We need to drastically reduce both the CO2 and SO2 from going into the atmosphere, and the only way to do that is stop burning fossil fuels.

    Become energy/resource efficient/conservative. Reduce, reuse, recycle, & use alt energy. These are the best, easiest solutions, and can be done cost effectively for at least a three-fourths reduction in the U.S. We just need the will to do it.

    If people don’t have much upfront money & our govt is dragging its heals in helping, they can start with the most cost-effective measures, such as a $6 low-flow showerhead with an off-on switch, which can reduce hot water use by half & save over $100 per year on water and energy bills. Then with those savings invest in compact fluorescent bulbs, insulate, caulk windows. Move closer to work on next house move. And there are hundreds of other low-cost and free measures that save $$$ without lowering living standards. Eventually one might even save enough to buy a Sunfrost refrigerator (uses only 10% the energy, costs $2600, but saves enough to pay for itself in about 12 years, counting also less veggie spoilage — and goes on to save hundreds every year. Then, who knows, maybe one could save enough for an energy efficient hybrid, EV, or plug-in EV, or at least a good down-payment for one.

    This all takes time, and we should have started down this path 20 years ago. What a shame and waste. Light trucks were only 10% of the car market in 1980, but in recent years (with SUVs, which are classified as light trucks) about 50% of the new car market. They emit 47% more pollution and 43% more greenhouse gases than regular cars. Even though auto efficiency has vastly improved, we’ve been going backwards full-speed behind. Considering SUVs/trucks are more dangerous to their drivers & passengers, and to others on the road, this is utter craziness.

    And don’t get me started on peak oil, which John Q public has known about since the 1970s, but apparently had a concussion and forgot about it — probably in an SUV roll-over accident.

    Comment by Lynn Vincentnathan — 20 Aug 2008 @ 1:41 PM


    We spent some time discussing this paper before its publication as can be seen from the back and forth between Alan Robock, Tom Wigley and myself in the link above.

    Of note is my comment:

    “As noted, the models do not consider the possibility of an equilibration of the climate with a steady increase in aerosol as would actually occur. Thus, the modeling is deficient in addressing this important reality.”

    And Alan’s response:

    “I am not sure what you mean by “important reality.” As we point out in the paper, such scenarios could be investigated, but first you have to decide on how you want to control the climate. Do you want to keep it constant? Cool it back to pre-industrial times? Tom Wigley already used a gradually ramped up aerosol loading in his 2006 Science paper, and other presented such scenarios at AGU. What we present is the climate equilibration to a constant SO2 emission and gradually changing anthropogenic forcing. The results are as interesting as any other hypothetical forcing scenario.”

    So it is important to consider the assumptions made in these modeling studies in assessing their value in predicting changes in precipitation.

    I also point out that the predicted decreases in precipitation from the modeling are within the normal range, although a prolonged decrease of the magnitude predicted might have a more significant impact on agriculture. The models don’t take into account lessened evaporation and adjustments to crop irrigation over decades that could compensate for the reduced rainfall.

    Those of us studying geoengineering, almost universally, do not advocate it as a substitute for emissions reductions, only to give time for the development and deployment of the replacement technologies.

    Thus, the methadone analogy used is inappropriate. The treatment of Type II diabetes is a better one.

    There is no hard evidence that aerosol geoengineering would (a) result in dangerous reductions in stratospheric ozone or (b) lead to harmful acid precipitation.

    While it is true that implementation of aerosol geoengineering alone or in combination with some other geoengineering technology or technologies will likely involve some trade offs, these have yet to be discerned and to cavalierly dismiss geoengineering as is still the conventional wisdom among the scientific community and the chattering class is itself a risk we cannot afford to take.

    Comment by Alvia Gaskill — 20 Aug 2008 @ 1:46 PM

  26. Richard (22), interesting scenario that gives one pause — the politicians will love it. Plus don’t forget their glee with the massive resources they’ll control and dole out with a major geoengineering solution.

    Comment by Rod B — 20 Aug 2008 @ 1:53 PM

  27. Re 17 Gacin

    when I write “with interest I follow when capturing CO2 from the air will be the lowest-cost system”, you ask: “Does this mean you support a carbon tax of up to $250 ton-CO2 to pay for it?” ???

    I see I’m dealing with a topic you aren’t familiar with.

    Well, it’s really advisable climatologists don’t mess with economy and technical innovations to solve the problems they try to foresee.

    [Response: I might say the same thing about lawyers and climate science, but that would be unproductive. Since air capture is always going to have a finite cost (and will always be more expensive than CCS at power stations and other point sources) (see our previous discussion), it places a cap on how expensive any other solution can be. But regardless, it still needs to be paid for. Why did you bring it up now in the first place? – gavin]

    Comment by Timo Hämeranta — 20 Aug 2008 @ 2:03 PM

  28. Proponents of geoengineering should probably read R.K. Merton’s “The unanticipated consequences of purposive social action”. Published in 1936, it is widely available on the web and still germane for all who practice science and engineering.

    Comment by BillS — 20 Aug 2008 @ 2:40 PM

  29. >
    coming up 404 not found at the moment.

    Do they address whether this much sulfate will cause a transient spike in surface ocean pH as it rains out? I’d guess the total is trivial once completely dispersed in the ocean but the transient might be a worry.
    (Not to mention whatever excess fossil fuel is burned during a geoengineering interval)

    Comment by Hank Roberts — 20 Aug 2008 @ 3:13 PM

  30. The person with their comment #8 has started a good point – the Geoengineering modelers did not consider the effects of war as nations decide to stop the experiment that might cause massive destruction in their countries … trying to get countries to agree and then not go to war for trivial reasons (such as non-existent WMD’s) is hard enough – the major threat of changing rain patterns for the ill and/or agriculture collapse is the stuff of nightmares for world stability. Then, simply trying to create the international law required, and prevent any resulting war if some major country suffers one or more of these possible problems, would appear to rule out any possibility of such an experiment ever really being attempted.

    Comment by DBrown — 20 Aug 2008 @ 3:13 PM

  31. I can only hope that those who wish to use Stratospheric Sufur Dioxide Injections to ‘Geoengineer’ us out of having to deal with ‘The Global Warming Crisis’ most pressing Consequences in a sensible ‘Al Gore-ish’ manner, can also figure out a way to ‘Geoengineer’ us a New Source of Oxygen! :-(
    Though no one seems to have considered this fact; put-ting all of that additional SO2 into the Atmosphere will only contrubute (along with the CO2) to the Acid Rain that will then itself contribute to the Major Issue of ‘Oceanic Acidulation’, which is itself predicted to reach ‘The Crisis Point’ by as early as 2030.
    This ‘other problem’ – which is also exacerbated by the increasing Atmospheric CO2 Levels, our Industrialized Farming Practices (the source of ‘Dead Zones’), and various other Industrial Processes – is threatening to kill off the Oceans Tiny (but very Important!) Phytoplankton; as it will soon begin to prevent them from forming their Carbonate Shells!!!
    Because Phytoplankton produce up to 60% of The Oxygen that we ALL Breathe, and we’ve already cut down TOO MANY oof The Rainforests’ Trees that are the source of the other 40%; just how are we going to replace BOTH of these Sources, once they’re BOTH gone! :-(
    Oxidizing Coal to make the Power to electrolicise(spelling?) H2O?!? :-(
    Got Maxwells Demon in a Bottle, do ya’ Dr. Wood?!?
    You must be NUTS – or out of synch with Oceanographic Sciences, Bubba!!! :-(
    Please apply that ‘Great Mind’ of yours to the problem of getting all of us off of our Carbon Junkie habits!!!
    Think: Old School ‘Yankee Ingenuity’ to the Rescue! ;-)
    If we Free our Minds – and do this thing Right, then the World will be bound to FOLLOW! ;-)

    Comment by James Staples — 20 Aug 2008 @ 3:49 PM

  32. Geoengineering can only be a feasible short-term “solution” in sync with a longer term one. We cannot commit to throwing out SO2 for centuries to millennia (the long CO2 lifetime), it does not solve ocean acidification, there are regional effects even if the global average remains unchanged, and other things. Actually removing the CO2 from the atmosphere is an interesting idea, but I don’t really know much about it.

    Comment by Chris Colose — 20 Aug 2008 @ 4:14 PM

  33. Alvia Gaskill,25, wrote :

    “There is no hard evidence that aerosol geoengineering would (a) result in dangerous reductions in stratospheric ozone or (b) lead to harmful acid precipitation.”

    Hang on. You seem to have this the wrong way around. I want hard evidence that it *would not* lead to a) or b) or any other similar catastrophic unpredicted results.

    I consider the proposal to be utterly irresponsible.

    I remember similar proposals, to fly ozone in balloons up to the stratosphere when the cfc disaster became apparent. And putting giant mirrors into space orbit, and so forth. The media and politicians just love a sci-fi techno-fix. But, IMO, all this proposed tinkering is like mediaeval medicine, ‘apply leeches and mercury and sheep-droppings’. The unfortunate patient is hastened to their demise.

    If it goes wrong, we don’t have a second planet from which to observe our mistake, and say ‘Hey, that’s not right, let’s try Plan B’. The dumb experiment we’re already conducting now, by failing to reduce CO2 emissions, is reckless enough, without adding more follies that multiply the problems we already have.

    Comment by CL — 20 Aug 2008 @ 4:30 PM

  34. Hey why don’t we just mandate a 25% increase in airline seat width and leg room then required contrail only flight altitudes until we figure the rest out?

    Comment by captdallas2 — 20 Aug 2008 @ 5:03 PM

  35. (1) Produce carbonaceous materials such as biochar or torrified wood from biomass.
    (2) Sequester in abandoned mines or carbon landfills.

    The cost is less than about $135 per tonne of carbon in developed countries and I opine about half that in the Global South.

    Just this, spending about 1–2% of WGP for the rest of the century reduces atmospheric CO2 to around 290—300 ppm (and solves the ocean acidification as well). Of course, it makes more economic sense to burn the torrified wood instead of coal, so reducing the proportion of the GP required for sequestering the excess carbon already added to the active carbon cycle.

    Comment by David B. Benson — 20 Aug 2008 @ 5:16 PM

  36. Presumably this doesn’t apply to geoengineering, where the direct effect of the engineering is to remove CO2 from the system (as in dumping slaked lime in the ocean)?

    Comment by Sam Vilain — 20 Aug 2008 @ 6:44 PM

  37. ..and surely the simple act of ‘putting’ 100Mt of anything up to 100km altitude will require the emission of a bit of carbon – like about 5e6 tonnes as a minimum if we get it there with 100% efficiency. As with most of these efforts we simply start chasing our tell to hell – basically!

    Comment by Nigel Williams — 20 Aug 2008 @ 7:35 PM

  38. A modest (apologies to Jonathan Swift) geo-engineering proposal:

    The 1400 watts per square meter we receive from the Sun at the top of our atmosphere translates to about 240 watts per square meter at the surface of the Earth when albedo and the Earth’s rotatation are taken into account.. This assumes a mean distance from the Sun of about 150 million kilometers. If the Earth were 152 million kilometers from the Sun we could reduce the Solar constant from 240 to about 235 watts per square meter!* Since a doubling of anthropogenic carbon dioxide in the atmosphere increases the energy forcing by about 4.5 watts per square meter, the 5 watts/meter^2 would offset the effects of a doubling of CO2!

    In other words to erase the projected forcing of global warming by doubling the atmospheric CO2 we would merely have to move the Earth about 2 million kilometers further from the Sun, perhaps by “launching” our satellite Earth using the thrust needed by means of nuclear explosions on the floor of the Pacific (Don’t try this at home).
    I say ‘merely’ but there are downsides to this solution. For one thing we could overshoot and a possible outcome could be that we’d become a satellite of Jupiter! There would also be effects from the force caused by the initial acceleration in accord with Newton’s second law. Who knows what these effects would be. Momentous earthquakes? Seismic sea waves tens (hundreds?)of meters high? In that case we could resort to other geo- engineering solutions, e.g. building massive sea walls around contintental perimeters, beforehand.

    Or maybe we’d just be better off by switching to alternative fuels.

    * Total Solar radiation at a Solar surface temperature of 5800K and a radius of 7.0 x10^11m, Ss= 4piR^2xsigma(T^4)=
    The solar constant, on a unit normal area per unit time, falling to Earth is given by Ss=4pi(D^2)Se or Se=Ss/4pi(D^2)
    (from “Exercises in Environmental Physics” by Valerio Faraoni, Springer, 2006)
    , Se = Ss/4pi(D^2)= 3.95×10^26W/ 4xpi(1.50×10^11)^2=1398~1400W/m^2
    Adjusting for albedo and geometry 1400(1-.31)/4=241or about 240W/m^2
    If the Earth Sun Distance were 1.52 x10^11m then 3.95×10^26/ 4pi)(1.52×10^11)^2=1360W

    Comment by Lawrence Brown — 20 Aug 2008 @ 8:41 PM

  39. 1. Reference Book: “The Paranoia Switch” by Martha Stout. Coal companies push your buttons and pull your chain, just like George W. Bush, [edit] Senator McCarthy and others. MRI used to be called NMR. The name was changed to get patients into the scanner. Most Americans are paranoid of terrorists and all things nuclear. If the “human” brain had been designed by a competent god, the coal industry would not have a $100 Billion per year cash flow and George W. Bush would never have had a chance of being elected once. We all know that we have to convert all coal fired power plants to nuclear worldwide by 2015, but it won’t happen because the average American has an irrational fear of all things nuclear. To solve the global warming problem, the whole USA needs to be sent to a mental health professional. We have enough time and technology. It is only mental health and intelligence that is lacking.

    2. I infer that putting light deflectors at the first earth-sun lagrangian point L1 would be more expensive that putting SO2 in the stratosphere. Would the L1 solution meet with approval climate wise? The L1 solution would at least avoid the SO2.

    [Response: Worse. Much more expensive. How do you easily turn it off if it doesn’t work out? It doesn’t deal with acidification either etc… -gavin]

    3. I have heard a rumor that the US government is already putting something bad high in the atmosphere already. See Any comments on chemtrails in the sky?

    [Response: Paranoid delusions. – gavin]

    4. No, it isn’t a carbon tax that we want. We want the burning of coal to make electricity to be illegal, worldwide, and soon. A carbon tax that ramps up steeply with time would be inadequate. Cap and trade is not a guarantee either.

    5. Sequestering CO2 should be reserved for industrial processes because industrial processes are the second largest source of CO2. Burning coal to make electricity is both the biggest single source of CO2 and the biggest source of non-natural radiation and metallic poison. Coal contains: URANIUM, ARSENIC, LEAD, MERCURY, Antimony, Cobalt, Nickel, Copper, Selenium, Barium, Fluorine, Silver, Beryllium, Iron, Sulfur, Boron, Titanium, Cadmium, Magnesium, Thorium, Calcium, Manganese, Vanadium, Chlorine, Aluminum, Chromium, Molybdenum and Zinc. There is so much of these elements in coal that cinders and coal smoke are actually valuable ores. We should be able to get all the uranium and thorium we need to fuel nuclear power plants for centuries by using cinders and smoke as ore. The impurities in coal vary wildly from place to place. Chinese industrial grade coal is sometimes stolen by peasants for cooking. The result is that the whole family dies of arsenic poisoning because Chinese industrial grade coal contains large amounts of arsenic.

    6. Moving earth to a higher orbit: See “New Earths” by Jim Oberg. You do it by making large asteroids pass in front of the earth, exchanging momentum by means of gravity. This is not recommended without first figuring out the consequences for orbital stability. Also, we would have to inhabit the entire solar system first, and terraform Mars, rendering the project moot.

    I have zero financial interest in nuclear power, and I never have had a financial interest in nuclear power. My sole motivation in writing this is to avoid extinction by H2S gas due to global warming.

    Comment by Edward Greisch — 20 Aug 2008 @ 9:34 PM

  40. Since this is all depressing, perhaps a bit of levity regarding changing Earth’s orbit outward: World Jump Day.

    Comment by John Mashey — 20 Aug 2008 @ 10:57 PM

  41. OK, so geoengineering by putting a small amount of engineered sun dimming aerosol into the upper atmosphere isn’t a magic bullet (i.e. change in precipitation levels). What is the alternative?

    The reason I bring this up is: “There is no linear predictability in terms of how ecosystems respond. The phenomena of collapse is one that we have under-appreciated, partly because of the feed-back mechanisms that we are still trying to understand.” –Achim Steiner, head of the UN Environment Programme, Oct. ’07

    “Leemans and Eickhout (2004) found that adaptive capacity decreases rapidly with an increasing rate of climate change. Their study finds that five percent of all ecosystems cannot adapt more quickly than 0.1 C per decade over time. Forests will be among the ecosystems to experience problems first because their ability to migrate to stay within the climate zone they are adapted to is limited. If the rate is 0.3 C per decade, 15 percent of ecosystems will not be able to adapt. If the rate should exceed 0.4 C per decade, all ecosystems will be quickly destroyed, opportunistic species will dominate, and the breakdown of biological material will lead to even greater emissions of CO2. This will in turn increase the rate of warming” –Leemans and Eickhout (2004), “Another reason for concern: regional and global impacts on ecosystems for different levels of climate change,” Global Environmental Change 14, 219–228

    In other words, any other viable alternative scheme to geoengineering must stop Earth’s surface temperatures from rise above the rate of 0.4 C/decade. By the way, in my opinion, the elevated greenhouse gas levels already in the air, combined with the future emissions from machines already built, plus increased natural emissions from carbon sinks becoming carbon emitters (i.e. permafrost melting) will cause the rate of warming to top 0.4 C/decade by mid-century.

    “Few seem to realise that the present IPCC models predict almost unanimously that by 2040 the average summer in Europe will be as hot as the summer of 2003 when over 30,000 died from heat. By then we may cool ourselves with air conditioning and learn to live in a climate no worse than that of Baghdad now. But without extensive irrigation the plants will die and both farming and natural ecosystems will be replaced by scrub and desert. What will there be to eat? The same dire changes will affect the rest of the world and I can envisage Americans migrating into Canada and the Chinese into Siberia but there may be little food for any of them.” –Dr James Lovelock’s lecture to the Royal Society, 29 Oct. ’07

    “Peak temperatures may rise twice as fast as average temperatures as climate change hots up.” –“Summer scorchers outpace global warming,” The New Scientist, 20 August 2008

    Comment by Brad Arnold — 21 Aug 2008 @ 1:23 AM

  42. Re 27 Gavin,

    Frank Zeman speaks about sodium or potassium, but I had in mind ‘artificial trees’. I had discussed of this alternative e.g. with my dear friend Alan Robock. He is reluctant, but I see it very interesting and promising way of geoengineering.

    About the IPCC recommendations and prevailing policies I copy one of my emails last year:

    (Instead of emission reductions) “again I refer to the total abstention from other future possibilities, although all the concerns deal with possible futures.

    Please see again:

    Goettmann, Frédéric, Arne Thomas, and Markus Antonietti, 2007. Metal-Free Activation of CO2 by Mesoporous Graphitic Carbon Nitride. Angewandte Chemie Vol. 46, No 15, pp. 2717-2720, April 2, 2007

    If needed, the future solution is e.g. this Artificial Photosynthesis.

    Besides, Nature and Man gets the extra biomass urgently needed.

    The main message is that Human Ingenuity will resolve this CO2 problem (if it exists at all).”

    Comment by Timo Hämeranta — 21 Aug 2008 @ 1:38 AM

  43. Sorry to double post, but putting sulfate particles into the air to dim the sun is a strawman argument against geoengineering since using engineered particles instead would be much less expensive and could be designed to avoid damaging the ozone layer:

    “A much-discussed idea to offset global warming by injecting sulfate particles into the stratosphere would have a drastic impact on Earth’s protective ozone layer, new research concludes. The study, led by Simone Tilmes of the National Center for Atmospheric Research (NCAR) in Boulder, Colo., warns that such an approach would delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic.” –“Injecting Sulfate Particles into Stratosphere Could Have Drastic Impact on Earth’s Ozone Layer,” National Science Foundation, 24 April 2008

    But: “The economics of geoengineering are—there is no better word for it—incredible. According to Teller et al. (2003: 5), engineered particles would be even cheaper (mainly because of the reduced volume of material that would need to be put into the stratosphere); they estimate that the sunlight scattering needed to offset the warming effect of rising greenhouse gas concentrations by the year 2100 would cost just $1 billion per year.” –“The Incredible Economics of Geoengineering,” Scott Barrett, 6 December 2007

    The scheme of dimming the sun with engineered particles injected into the upper atmosphere is a short run strategy of buying time to impliment the long run scheme of changing the carbon budget of the Earth.

    “The Greens’ resistance to geo-engineering sits very uncomfortably with its message that the planet is screwed and we’re all going to die…It suggests that they don’t actually believe their own press releases, and that they know the situation is not as dire as they would like the rest of us to think it is…It suggests that Environmentalists regard science and engineering as the cause of problems, and not the solution.” –Climate Resistance, 24 March 2008

    Comment by Brad Arnold — 21 Aug 2008 @ 3:05 AM

  44. If people are interested in possible solutions to the energy issue without need of increasing CO2, then thermo-nuclear fusion is a good option.
    Direct drive thermo-nuclear fusion is a possible solution. A Navy group proposed a KrF direct drive laser implosion system that was peer reviewed by an international team of experts in the field and deemed not just viable but likely to succeed. The cost, under half a billion dollars for a proto-type power plant. Development time, under ten years. Such a plant could replace all coal plants without the massive and extremely radioactive waste from a regular fission plant nor the danger of a runaway melt down or extreme danger of a nuclear explosion from a breeder fission reactor.
    Of course, the DOE does not have the money for such a test plant so the proposal was turned down.

    Comment by DBrown — 21 Aug 2008 @ 7:35 AM

  45. At the EGU last year there was a very interesting panel discussion on geo-engineering (with Ken Caldeira a.o.). An important point of discussion was whether the possibility of geo-engineering could decrease attempts to reduce emissions. Measures that alleviate negative consequences induce risky behavior, eg seatbelts cause drivers to drive less safely. But that shouldn’t translate in not using seatbelts, was the response. There is a real risk of a trade-off between geo-engineering and emission reduction, but I don’t want to summarily dismiss it either.

    “I hope I never need a parachute, but if my plane is going down in flames, I sure hope I have a parachute handy,” Caldeira said. “I hope we’ll never need geoengineering schemes, but if a climate catastrophe occurs, I sure hope we will have thought through our options carefully.” ( and elsewhere.) Initial model simulations suggest that a high-CO2 world with geoengineering is likely to be closer to the pre-industrial world than a high-CO2 world without geoengineering. (

    The challenge is to investigate the consequences and viability of different schemes, while being careful that it is not being (ab)used as an alibi not to work on emission reduction, which should be the first and foremost strategy to prevent dangerous climate change. Thus, geoengineering schemes should only be put into practice when catastrophe is imminent, as a last resort. Who will decide on that is a tricky question of course, to which I don’t have an answer. Hopefully any such decision will be informed by science however, and not overpowered by lobby groups. The influence of lobby groups on the current public and political discussion does not bode well that we can prevent or substantially decrease their influence in the near future, when they may call to focus on geoengineering instead of emission reduction strategies (rather than focus on both, but in reverse order).

    On a more “practical” note: Isn’t the scheme originally proposed by Latham (1990, 2002) to seed maritime clouds with sea salt aerosol (to enhance their reflectivity) probably more benign than injection SO2 into the stratosphere? It doesn’t seem impossible or prohibitively expensive either (which a space-based sunscreen would be for example).

    Comment by Bart Verheggen — 21 Aug 2008 @ 8:11 AM

  46. Many thanks for the highly interesting post, Gavin! Realclimate is *the* site for me to get the ammo to fight the sceptics’ pseudo-arguments.

    I just tried to download Robock’s paper but got a “Not found” message. This seems to be the correct link now:

    Comment by MichaelT — 21 Aug 2008 @ 8:56 AM

  47. Of course, Gavin is correct — What I mean to say is that it’s hard to imagine the current biosphere, i.e., the the one humans evolved in, surviving this century.

    Jeremy Jackson sees three scenarios for the oceans over the next 20-30 years, from best to worst:

    Scenario 1: Carbon emissions capped, nutrient runoff stopped, overfishing stopped

    Dead zones decrease; too late for megafauna; small fish survive.

    Scenario 2: Carbon emissions not capped, but nutrient runoff and overfishing are stopped

    Acidic, stratified oceans; demise of calcified organisms; anoxia below thermocline.

    Scenario 3: Carbon emissions not capped, nutrient runoff not stopped, overfishing is/isn’t stopped

    Global dead zones dominated by jellyfish and microbes; coastal waters too toxic for aquaculture and human habitation.

    Watch his presentation from December, Brave New Oceans. Then take a X-a-n-a-x.

    Comment by Jim Galasyn — 21 Aug 2008 @ 10:32 AM

  48. Brad Arnold,
    The most general reason for doubt about proposed geoengineering solutions is the likelihood of unintended and unpredictable side-effects – a point that has been made repeatedly. Denialists are often very keen to point out that the climate system is complex, much remains to be understood, etc., etc. – so you would think denialist sites such as “Climate Resistance” would find this point easy to grasp. The fact that they pretend not to in the quote you give casts serious doubt on their honesty.

    Comment by Nick Gotts — 21 Aug 2008 @ 12:12 PM

  49. re 22 Richard “Methadone is a pretty good metaphor — kind of like saccharine, sugarless sodas, and decaf coffee. Not really facing the problem.”

    Errr, you forgot “clean coal”?

    Comment by Richard Ordway — 21 Aug 2008 @ 12:58 PM

  50. Jim, it’s not the whole biosphere at risk here, except for very human-centric definitions of biosphere. It’s mostly the charismatic megafauna that are in trouble (if you include people as charismatic; debatable, yes).

    I’m sure the beetles will be fine — creation has always had “an inordinate fondness for beetles.”

    That experiment has already been run in many ways — wildlife finds H. sapiens more troublesome than any other environmental factor, vide the Korean DMZ, the Chernobyl hot zone, and so forth.

    Once the people are out of the way, Earth abides.

    Oh, wait …

    Comment by Hank Roberts — 21 Aug 2008 @ 1:06 PM

  51. The primary issue is not warming per se, but distribution of heat. Increased CO2 causes the arctic to warm, which melts ice, which floods coasts. Add sulphur and the entire planet can cool, but the arctic will still warm (and oceans acidify) as mankind keeps adding CO2. I noticed the graph shows arctic injection as a possibility. Is that an attempt to address this issue? How well can the cooling effect be localized to the poles?

    Comment by Richard Caldwell — 21 Aug 2008 @ 2:16 PM

  52. RE: 29 I don’t think there would be any spikes in surface ocean pH or longer term impacts either. The quantities are just too small. Most of the aerosol would descend at high latitudes, but a significant fraction would also fall out globally, including over land. However, no studies have been carried out on the potential acidification impacts and would need to be before any large scale projects.

    RE: 43 The idea of designing engineered particles instead of using those formed by chemical reactions is just that. An idea. It isn’t clear if it could be done either to reduce potential ozone depletion or extend the lifetime and increase the backscattering of the particles. My prediction is that by the time such materials could be produced in the quantities required, we will no longer need them.

    RE: 51 Because of the way in which both upper tropospheric and lower Overworld stratospheric air moves, aerosol precursor added to either one at high latitudes is expected to drift south to around 30 degrees N within a few months. This is based on observations of volcanic eruptions at high latitudes. In addition to possible distal effects on monsoons, the aerosol formed cannot be contained to say within a few degrees of its formation and may require much more than if the area of interest to have the sunlight reduced is for example, 80 degrees N to the pole. There is still debate as to whether some kind of short term solar radiation reduction can be obtained by upper tropospheric releases that would have lifetimes of less than one season and that would not have spillover impacts like the ones mentioned here.

    Comment by Alvia Gaskill — 21 Aug 2008 @ 3:47 PM

  53. Edward Greisch wrote: “We all know that we have to convert all coal
    fired power plants to nuclear worldwide by 2015, but it won’t happen because the
    average American has an irrational fear of all things nuclear.”

    We most certainly don’t “have to” build any new
    nuclear power plants, let alone “convert” all coal-fired plants to nuclear,
    in order to eliminate all GHG emissions from electricity generation.

    The USA has vast commercially-exploitable solar and wind energy resources, that
    are more than sufficient to produce several times as much electricity as the entire
    country currently uses, and to electrify our transportation systems as well. This
    can be done using existing technology, and it can be done far more quickly and at
    much lower cost than building new nuclear power plants, with none of the toxic pollution
    and grave dangers of nuclear power. And the technology is rapidly improving and
    dropping in cost as it achieves economies of scale. Moreover, once the infrastructure
    for harvesting wind and solar energy is built, the “fuel” is ubiquitous,
    limitless, and free and there are zero GHG emissions — which is not true of the
    nuclear fuel cycle.

    By 2015 many, many gigawatts of new wind, solar photovoltaic and concentrating solar
    thermal electric generation will be online in the USA and other developed countries
    — long before even a single new nuclear power plant is operational. And in the
    developing world, where rural electrification is vital for human well-being and
    social and economic development, and where it is economically impossible to build
    or operate large centralized nuclear power plants and the grids to distribute their
    electricity, there is an revolution is small-scale distributed wind and solar electricity
    generation. China in particular is rapidly becoming a world leader in both the
    production and deployment of wind and solar technology.

    There is simply no need for nuclear power, so there is no need to deal with its
    toxic pollution and the grave dangers of catastrophic accidents or attacks on nuclear
    facilities or fuel transports, or the risks of nuclear weapons proliferation associated
    with the proliferation of nuclear power technology and nuclear fuels.

    Comment by SecularAnimist — 21 Aug 2008 @ 3:57 PM

  54. See: Changes in Earth’s Albedo Measured by Satellite
    Bruce A. Wielicki, Takmeng Wong, Norman Loeb,Patrick Minnis, Kory Priestley, Robert Kandel,
    Science 6 May 2005:
    Vol. 308. no. 5723, p. 825
    DOI: 10.1126/science.1106484

    They say:
    “Measurements from space since the 1970s give a global annual Earth albedo of ~0.29. The average incident solar radiative flux is 341 W m-2, so that a change in albedo of 0.01 represents a global energy balance change of 3.4 W m-2, similar in magnitude to the impact of doubling carbon dioxide in the atmosphere. Global albedo can change with changes in Earth’s cloud fractional coverage, cloud thickness, aerosol amount, forest cover, or snow and ice cover. For example, a 2-year change in albedo was caused by the large Mount Pinatubo volcanic eruption in June 1991. Stratospheric aerosols from the eruption increased global albedo by up to 0.007 because of the reflection of an additional 2.5 W m-2 of solar radiation over the following 2 years”

    People have pointed out many reasons to *not* want to do geoengineering via sulfate aerosols. Let me point out some more, akin to the decreasing relative usefulness of:

    – avoiding generating CO2 via efficiency
    – capturing CO2 at a power plant
    – capturing CO2 from the air later on

    Sunlight is useful:
    a) It’s necessary for plants, and slowing their growth worldwide is not a plus, and Liebig’s Law of the Minimum is relevant.
    b) Solar PV and CSP need it to convert to electricity, and reducing their efficiency is not a plus.
    c) Solar thermal systems on rooftops need it to heat water for household use or swimming pools.
    d) It can lessen use of electricity for lighting.

    SO, why on earth would we spend a lot of energy to *lessen* the useful energy we get from the Sun? I.e., raise the albedo high in the atmosphere?

    We have:
    Visible light ->
    surface ->
    useful energy + visible reflected + heat emitted

    and the real goal is reducing the emitted heat, either by increasing the fraction of captured useful energy, or increasing the surface albedo to reflect more of the energy in visible wavelengths.

    Why would we not want to:
    e) Convert more sunlight into electricity and useful heat at ground level, especially if the sun-capturing elements generate less waste heat than {surfaces they cover, powerplants displace}. People have proposed floating PV farms to cover lakes, for example [which might also reduce evaporation a little]. PV panels definitely improve dark roofs. Higher-efficiency PV generates less direct waste heat.

    f) Work hard to increase the albedo of built-environment surfaces, especially in sunny areas. For example, see p21-36Part 2 Cool Urban Surfaces and Global Warming, in a talk of Art Rosenfeld, CA’s famous efficiency pioneer.

    This doesn’t remove CO2 from the air, and it’s nowhere near as important as efficinecy & cutting back on GHGs, but it can certainly help with local UHI effects, and reduce power for air conditioning.

    I think e) and f) are likely to be negative-cost actions.

    g) Finally, if one can’t use some acreage for power, useful heat, or growing something useful, maybe one can find ways to raise its albedo terrestrially, which surely seems cheaper and safer than using energy to keep more sulfates in the atmosphere.

    I once did a humorous back-of-the-envelope calculation that 3 year’s world production of aluminum would suffice to cover Greenland with aluminum foil, which is probably not a Good Idea (covering ice is especially silly).

    Less crazy, might be to cover hyper-arid lands with mirrors on wooden frames (thus sequestering some carbon). Deserts at least already have lots of sand, although course, using them for solar power is preferable. If there are areas of tundra whose soils won’t let trees grow, that might work as well.

    More seriously:
    Some Albedos:
    .02-.35 water (depending on angle)
    .05-.20 asphalt
    .10-.27 urban areas
    .15-.20 tundra
    .25-.30 desert
    .75-.95 new snow

    It’s not obvious how one would practically do much to raise the albedo of oceans, but lakes might be plausible, and urban/asphalt can certainly be improved.

    Sulfates might try to raise the average albedo from .29 to .30 fairly uniformly. On the other hand, if one can raise about 2% of the globe by about .5, that gets the same .01 effect to offset the temperature effects of CO2 doubling. Land is 29% of the surface, so we’d need to raise albedo by .5 on 6.9% of the land.

    According to Rosenfeld’s pitch, dense urban areas are about 1% of *land*, and less-dense urban areas are another 1%, so that’s 2% of the 6.9%, leaving 4.9% of the land. Hyper-arid lands are supposed to be about 4% of land, but there’s plenty more arid land, and of course mirrors would raise albedo from .30 to .95 (at least), so it’s better than .5.

    This is *not* a proposal to start doing this, and obviously, I haven’t done any serious studies, just really rough numbers. It’s just an observation that:

    a) We should do all the obvious things (emission reduction, efficiency, albedo increase in normal built environment, solar power).

    b) BUT IF we feel the need to increase albedo for a while, global aerosol production seems dominated by local terrestrial changes.

    Comment by John Mashey — 21 Aug 2008 @ 4:25 PM

  55. I would like to hear some discussion of the proposed geo-engineering solution of fertilising the oceans with iron or other minerals so as to sequester the CO2 through plankton. My gut response is that this would cause massive algal blooms, but maybe I’ve misunderstood. What are the costs/benefits of this approach?

    Comment by James Haughton — 21 Aug 2008 @ 7:43 PM

  56. Can aerosols in high latitude winter atmospheres cause warming by trapping more radiation than they reflect?

    [Response: Very good question. Answer yes… but it’s a complicated story (aerosol type etc.) – we have a paper upcoming on just such impacts. – gavin]

    Comment by Lab Lemming — 21 Aug 2008 @ 8:31 PM

  57. I’m once again disappointed by RC’s dismissive attitude toward even stop gap proposals to blunt the worst effects of AGW via geoengineering.

    Methadone maintenance is one analogy, here’s another:

    The house (read planet) is burning down. The editors at RC would have us watch it burn down while saying we didn’t build it right in the first place, so we’ll just let it burn and build it again. I (and others) would say let’s throw some water on it (read geoengineering) and if we have to deal with some water damage, so be it.

    I’m not advocating that we shouldn’t address the root cause, fossil fuels. On the contrary, but looking at current climate trends scares the crap out of me and we may have to do something more drastic in the short term to prevent disastrous consequences.

    Question for RC editors and readers:

    If you were a subsistence farmer in the river deltas of Bangladesh and were given the choice of uncertain weather or the certainty of being flooded out of your home by sea level rise, which would you choose?

    Comment by Peter Backes — 21 Aug 2008 @ 8:36 PM

  58. Edward Greisch writes (predictably):

    We all know that we have to convert all coal fired power plants to nuclear worldwide by 2015

    What you know and what we all know exhibit some divergence.

    Comment by Barton Paul Levenson — 22 Aug 2008 @ 5:53 AM

  59. Peter Backes, 57

    I don’t think your analogies are very illuminating. The unfortunate Bangladesh farmer (and billions of others) is likely to get uncertain weather *and* sea level rise, and all the geo-engineering suggestions I have seen so far look to me as if they will guarantee additional woes without fixing the problem.

    It’s like the words of the doctor, ” The surgery was successful, but, er, the patient died..”

    All the info that is coming in concerning global prospects alarms me greatly, so I share your distress. Just that I think it would be wiser to cease the activities that we *know* already are making things
    worse. Well-meaning suggestions are fine, but mostly they appear to me to be ill-considered and just digging ourselves into a deeper hole. If we cannot protect the forests we already have, what’s the point in suggesting planting new ones in deserts, and so forth ? What’s the point in adding iron to the oceans and messing them up even more with algal blooms, etc ?

    I think everyone should watch the presentation that Jim Galasyn (thanks) posted. If that doesn’t wake people up to our dire situation, I doubt anything will. Here it is again

    Comment by CL — 22 Aug 2008 @ 6:28 AM

  60. Peter Backes #57: I think you completely missed what the RC post is trying to argue. It is not dismissive of geo-engineering as such. It is pre-emptive of naive technology faith, already being used today by the inactivists to justify not doing anything.

    A more proper metaphor would be: stocking up gasoline in your cellar, well knowing that the fire station is right across the street :-)

    Comment by Martin Vermeer — 22 Aug 2008 @ 7:45 AM

  61. I’m curious what all the geo-engineering naysayers would say _if_ we had a somewhat different situation:

    Due to a natural reduction in solar output (that has recently been understood to be long term), a new and apparently very severe ice age is starting. Should we be exploring geo-engineering solutions to mitigate this new natural global cooling?

    [Response: None of those statements are true. But just for fun, let’s assume they were – what is the easiest way to raise temperatures? Deliberate manufacture and release of HFC’s. Dirt cheap, no stratospheric injection required due to stability, GW potentials in the 10’s of thousands, little or no effect stratospheric ozone. What’s not to love? In other words, new ice ages are the very least of our problems. – gavin]

    Comment by Steve Reynolds — 22 Aug 2008 @ 2:03 PM

  62. Hank says, “it’s not the whole biosphere at risk here, except for very human-centric definitions of biosphere. It’s mostly the charismatic megafauna that are in trouble (if you include people as charismatic; debatable, yes).”

    LOL! I don’t disagree with taking the long view, but I do suggest that it’s more than just the charismatic megafauna at risk — it’s whole ecosystems in which those species are embedded. For example, remove the apex predators, like great sharks (which are already functionally extinct) and their entire ecosystem unravels in a trophic cascade, typically leaving a desert populated with a few opportunistic species. This has been observed off the N. Carolina coast.

    Personally, I’m horrified at the idea of witnessing the last dolphins and whales washing up dead, killed by starvation and neurotoxins from Karenia brevis algae blooms. Maybe that’s human-centric of me; I prefer to think of it as empathic.

    As Prof. Jackson says, “The future is bright for dinoflagellates.”

    Comment by Jim Galasyn — 22 Aug 2008 @ 4:17 PM

  63. Jim, 62, I was quite shaken by Jeremy Jackson’s lecture. The rise of slime.

    There are streams, ditches, ponds, locally here, amidst agricultural land. They appear devoid of life, just black slime. I think that this is because of run-off from the surrounding fields which are regularly blasted with chemicals to speed up the growth of monoculture of grass, which is converted into silage and fed to cows, (which are also forced in a similar way to maximize milk yield, and have very short and un-natural lives). Eutrophication.

    Compare those watercourses to the few relatively pristine and unpolluted streams left, which are actually still quite interesting to look into because of the varied species they contain.

    Seems we are doing a similar thing, writ large, for Earth. We end up with a few scavenging bands of humans, a bit like the Inuit, eating rats and cockroaches, wandering along the shores of septic, stinking seas, and looking for useful bits of metal amongst the detritus of the dead civilization that turned the forests into deserts.

    Does anybody think this is a good idea ? Does anybody think we will do anything effective to avoid that result, in the time we have available ?

    The way I see it, I cannot think of any greater crime that people have committed, or could commit. This awesomely beautiful fabulous planet produced us, and, instead of honour and respect, we turn it into a poisonous junkyard. We don’t deserve to survive.

    Whose to blame ?

    reCaptcha ‘next tyranny’

    Comment by CL — 22 Aug 2008 @ 5:58 PM

  64. Hey CL, have you seen Wall*E? I think you’d like it. The whole first act is a meditation on the scenario you describe, almost completely without dialog.

    Comment by Jim Galasyn — 22 Aug 2008 @ 8:36 PM

  65. Thanks for the tip, Jim. I just watched the quicktime trailers. Maybe I’ll see it complete someday.

    Do you ever walk the sea shore ? the quantities of manmade rubbish, mostly plastic, is astounding. It wasn’t like that, even thirty years ago. I guess the holocene-anthropocene era will be marked in the geological record by a layer of plastic fragments, fossilized dolls heads, compressed milk bottles, fishing net, and the like.

    Some people think that the human population will crash, back down to palaeolithic levels, and then start all over again, but maybe wiser. But the easily found ores and oil won’t be available, so I doubt that the sequence of events could follow the same course to rebuild civilization the way it has developed. And I doubt there’ll be much around to hunt and gather.

    Some people have faith in technological innovations to save us. Perhaps there’ll be some surprises, but seems very ‘iffy’ to me.
    But I don’t rule it out completely. I have some documents that record patented ideas to make horse-drawn vehicles more comfortable. Investors were very excited at the time and seem to have had no awareness or foresight that in a couple of years the early motor cars would make their transport obsolete.

    I came across a striking photograph, which kinda sums up the whole of human prehistory and history, complete with depleted, ravaged landscape, and our love of weapons and gadgets, and, judging by the guy’s eyes, mood altering chemicals.

    “All we have to do to destroy the planet’s climate and its biota and leave a ruined world to our children and grandchildren is to just keep on where we’re going today, just keep releasing greenhouse gases at current rates, just keep degrading and homogenizing and destroying our biological resources, just continue releasing toxic chemicals at current rates, and by the latter part of this century, the world won’t be fit to live in.” – April 2008, James Speth, Professor of Environmental Policy at Yale University

    reCaptcha, ‘urgently war’

    Comment by CL — 22 Aug 2008 @ 9:32 PM

  66. RE: 60

    I’ve been following RC for years and I don’t think I’ve missed the point of this post or of previous posts on this subject. RC does not like the idea of geoengineering, period.

    I don’t like the idea either. After all, we are already unintentionally geoengineering the planet with carbon emissions that desperately need to be brought under control.

    The question RC has not, in my opinion, addressed honestly is this: What if we find ourselves, despite all of our best efforts to rapidly control greenhouse gasses, past Dr. Hansen’s famous ‘tipping point’ in a few years? What if the forecasts say we are going to have a sea level rise of a meter or more before the end of the century? Do we do nothing?

    The subject of geoengineering is not going to go away because smart people hide away in their academic ivory towers. My hope would be that the folks at RC would take on this question in a serious manner and vet the short term solutions that would do the least harm and be the most predictable in result. If the climate starts to run away, you can bet someone’s going to do it whether RC participates or not.

    I’d like to suggest a subject line for a future RC post: “In Case of Emergency”

    Comment by Peter Backes — 22 Aug 2008 @ 9:37 PM

  67. I’m not opposed to geoengineering in principle, but we should be very sure that it will have the desired effects before we implement.

    There’s a semi-serious post at Cquestrate:

    This is easy. Simply wait for favorable winds and detonate a huge, clean nuclear device under an appropriate seaside limestone formation. … This energy can be used to efficiently and cheaply liberate the lime and simultaneously distribute it around the world via existing wind and ocean currents.

    Terrifying, but seductive.

    Comment by Jim Galasyn — 22 Aug 2008 @ 10:04 PM

  68. > huge, clean, nuclear
    Two out of three ain’t good enough.

    I like my idea better — carve big limestone or dolomite or chalk boats, float-tow them out above the handiest undersea volcano, equip them with ‘smart bomb’ heat seeking steering, and scuttle them so they dive right into the magma.

    More jobs, less fallout, comparable effect.

    Comment by Hank Roberts — 22 Aug 2008 @ 11:12 PM

  69. Peter Backes, nobody likes the idea of geo-engineering. And still we may end up having to resort to it.

    As for preparation, none is needed. There are two bottlenecks, a small one and a big one: (1) logistics, and (2) knowing what the heck you are doing, and how the system will respond.

    As to (1), less than even a small war, of which the US alone has a couple going as we speak.

    As to (2), it’s called climatology. We need urgently to get much, much better at it anyway, precisely because of the ongoing unintentional geoengineering. Intentional geoengineering is just one narrow application. Everything RC, and the scientists behind RC, are doing will benefit it if it comes to pass. Playing Dr Strangelove now is just sicko.

    Comment by Martin Vermeer — 23 Aug 2008 @ 1:39 AM

  70. Peter, #66. Well what we can do NOW is reduce our carbon output, extending the time over which we can ascertain what will work.

    Hank, #68, I think that idea is a bit silly. For any sufficiently large boat, neither stone has the required tensile strength. So you’d have to make large flotillas out of many smaller boats. And how will we get them? Convicts carving them and manhandling to the sea?

    You’d be far better off making something that will use seawater and carbon to create sequestered carbon in situ and dump it there. At least that way the mountain is freely coming to mohammed.

    Comment by Mark — 23 Aug 2008 @ 3:22 AM

  71. RE: 69

    Martin – Thank you for agreeing that geoengineering might become necessary! (and I have not been advocating that a geoengineering solution is necessary at this time)

    Of course the scientists at RC are a valuable resource on this subject – that’s why I’ve been chiding them to take it more seriously.

    With respect to the Dr. Strangelove analogy, I don’t agree. Better to have a plan to fight a fire before one starts. There’s nothing Dr. Strangelove about being prepared (and we’re not talking about a mine shaft gap).

    Comment by Peter Backes — 23 Aug 2008 @ 8:30 AM

  72. Assuming the methadone analogy is reasonable, does that mean that injecting aerosols as a “temporary fix” is so wrong? The point is that sometimes you need to buy time, and it seems to me there is a reasonable argument that in this case that is true. I’m not a climate scientist (I’m a mathematician), but from what I can gather things are pretty bad, and even if you make the Pollyanna assumption that global carbon usage could decrease significantly and quickly (say 2% a year for the next 40 years, hah hah) we’re still in deep doodoo. I mean is it better to let an addict die, or put them on methadone and give them a chance? They might die anyway, but is it worse? Other bad things might happen, but is it worse than being dead right away?


    Comment by Jeff — 23 Aug 2008 @ 10:29 AM

  73. Btw Hank, I posted your idea over at Cquestrate, with attribution. Fun discussion over there.

    Comment by Jim Galasyn — 23 Aug 2008 @ 10:47 AM

  74. As Hank notes, we are always free to do nothing and let Earth shed itself of most of us.

    As an alternative, I believe a climate “emergency” will happen fairly soon, such as an ice free Arctic Ocean, a resulting spike in Arctic temperatures, and a frightening acceleration of the melt of Greenland.

    Since such a scenario could quickly spin out of control and lead to the shedding of most people from Earth anyhow, I don’t see how we won’t try geoengineering…unless of course wars, cascading financial failures and resource shortages make such plans impossible to organize…back to paragraph 1.

    I’d rather RC take a more neutral tone on the subject of geoengineering and compare the various options dispassionately.

    Comment by Jason — 23 Aug 2008 @ 7:03 PM

  75. Jason, there’s no geoengineering proposed so far that’s credibly going to stop increasing the amount of CO2 in the atmosphere and the ocean, and anything else is missing the point given the rate of change in the oceans. You’re _seeing_ dispassionate assessments. Come up with a proposal that will keep the ocean pH constant and you’ll see passion.
    “strain receives”

    Comment by Hank Roberts — 23 Aug 2008 @ 10:42 PM

  76. Hank,

    How about this (however unlikely it is) as a scenario where geoengineering would be justified:

    Even with just above today’s CO2 levels, massive amounts of methane start to be released as the Artic warms in a large positive feedback effect. CO2 emissions are dramatically reduced in response, but geoengineering is needed to stop the methane emissions.

    Comment by Steve Reynolds — 24 Aug 2008 @ 10:39 AM

  77. In comment 27 gavin said,

    Since air capture is always going to … be more expensive than CCS at power stations and other point sources) (see our previous discussion), it places a cap on how expensive any other solution can be. But regardless, it still needs to be paid for. Why did you bring it up now in the first place?

    When I brought it up, I did so because it differs in kind from the sulphate aerosol thing. It is an exact remedy rather than an inexact one. Otherwise said, rather than being a SACTCAR measure, it is a BTRO one. So even if it did cost more, this would not suffice to dismiss it from consideration.

    In that previous discussion, Dr. R.D.Schuiling asserted the cost per tonne CO2 would be US$10-15. (Some discussion here has referred to the olivine dispersal idea as mine; it is not.)

    Captcha “into Puritani”

    Comment by G.R.L. Cowan, H2 energy fan \'til ~1996 — 24 Aug 2008 @ 12:01 PM

  78. Steve, your scenario is not unlikely at all; if fact, these new methane emissions may have been detected already. Large quantities of CO2 may also be released, on the order of 100s of gigatons.

    This positive feedback is very worrying, and it’s hard to imagine any geoengineering scenario that can mitigate it.

    Comment by Jim Galasyn — 24 Aug 2008 @ 12:18 PM

  79. Steve, once you assign any significant risk to the scenario of clathrates boiling out of the ocean sometime in the next half millenium or so, you’ll be arguing very hard for reducing the total CO2 in the atmosphere, along with Hansen — not continuing burning fossil carbon and adding other stresses like a sulfate cloud.

    Apropos setting off a nuclear bomb in a limestone, someone should look into the nuclear bomb tests done on Pacific coral atolls for any evidence it makes sense.

    “The bomb Bravo vaporized two complete islands of Bikini Atoll and part of Nam, the island at which it was detonated.” American Journal of Public Health.2001; 91: 1371-1376

    Too much water in any limestone material means way, way too much radioactive fallout downwind.
    The idea fails sanity check.

    Comment by Hank Roberts — 24 Aug 2008 @ 12:53 PM

  80. Apropos setting off a nuclear bomb in a limestone, someone should look into the nuclear bomb tests done on Pacific coral atolls for any evidence it makes sense.

    What immediately occurs to me is two things. One, the originator of the idea can’t be serious and should therefore refrain from commenting, and two, the comminution efficiency of a nuclear explosion would be several orders of magnitude lower than that of proper rock pulverizers. For hard rock they typically take 25 kWh(e) per tonne if 80 percent of the mass is to be in sub-100-micron particles, 50 kWh(e) per tonne for 80 percent below 25 microns.

    Comment by G.R.L. Cowan, H2 energy fan \\\'til ~1996 — 24 Aug 2008 @ 1:54 PM

  81. Steve Reynolds, 76,

    “…but geoengineering is needed to stop the methane emissions.”

    What geoengineering do you think would be effective re methane emissions ?

    Someone thinks that “4.5 billion people could die from Global Warming related causes by 2012”

    Comment by CL — 24 Aug 2008 @ 2:05 PM

  82. I fail to understand why sequestering massive amounts of carbon fails to be ‘geo-engineering’.

    [Cpathcha cryptically remarks “partition both”.]

    Comment by David B. Benson — 24 Aug 2008 @ 3:01 PM

  83. Er, yeah.
    For those who like selling newspapers, this is the kind of article they like.

    A “weeks old” theory.

    “Bibliographic reference courtesy of Brad Arnold who has an extensive resrarch background on Global Warming.”
    He should have done more resrach.

    Comment by Hank Roberts — 24 Aug 2008 @ 3:13 PM

  84. Hank: “…you’ll be arguing very hard for reducing the total CO2 in the atmosphere, along with Hansen…”

    My scenario already assumed that. My point is whether it is prudent to have a well considered, researched, and maybe pilot tested plan in case that is not enough.

    Jim and CL,

    Stratospheric aerosols appear to be able to cause global cooling, but of course unwanted side effects could be a problem (unlikely to be worse than CL’s link though).

    Finding the best method and understanding its limitations seems to me to be worthy of considerable research effort.

    Comment by Steve Reynolds — 24 Aug 2008 @ 4:14 PM

  85. CL wrote in 81:

    Someone thinks that “4.5 billion people could die from Global Warming related causes by 2012″

    Where the heck is he pulling the figure 2012 from? Why should I give his opinion any weight? I know of some people out in the UK that still think the sun revolves around the earth. Doesn’t mean that I am going to regard the view any more credible.

    Don’t get me wrong: I believe that methane hydrates are a real threat. But the author you cite clearly isn’t an expert — the hydrate hypothesis (“clathrate gun”) goes back not weeks, but about eight years.

    Please see:

    Profile of James P. Kennett
    Tinsley H. Davis, Freelance Science Writer
    Proc Natl Acad Sci U S A. 2007 February 6; 104(6): 1751–1753.

    Comment by Timothy Chase — 24 Aug 2008 @ 5:00 PM

  86. > worthy of considerable research

    What direction for research does anyone see suggested after reading
    Robock et al ?

    [Response: Link updated – possibly Rutgers’ was having bandwidth issues (?) – gavin]

    Comment by Hank Roberts — 24 Aug 2008 @ 5:07 PM

  87. #82 David R. Benson “I fail to understand why sequestering massive amounts of carbon fails to be ‘geo-engineering’.”

    It doesn’t matter in the least whether you call it that or not. The point is that it would slow the increase in GHG concentrations in the atmosphere, without inevitable serious side-effects, which none of the other forms of geo-engineering proposed, so far as I recall, would do.

    Comment by Nick Gotts — 24 Aug 2008 @ 5:29 PM

  88. Hank Roberts (86) — Your link comes up 404 Not Found.

    Nick Gotts (87) — What are the bad effects of a sun screen at L1? Other than cost and that it does nothing for ocean acidification?

    Comment by David B. Benson — 24 Aug 2008 @ 6:27 PM

  89. We could use like 100 nuclear weapons in a massive ‘controlled demolition’ to set off the Toba supervolcano again!

    Or, you know, maybe that’s a bad idea…

    Comment by Lamont — 24 Aug 2008 @ 6:33 PM

  90. David, Gavin’s updated the link for Robock (thank you Gavin).

    > Sunscreen at L1

    1) building it locally
    2) getting it there (or some other appropriate location)
    3) keeping it there (it’s metastable, requires fiddling)
    4) getting back (see 2)

    There’s a preprint draft of Teller et al. (1997) here that elaborates:

    Attaining the ability to build a space elevator or three would seem to me more likely an accomplishment.
    Then we could try dumping material into the upper atmosphere or very near Earth orbit f in an energetically feasible way, and rely on its re-entering the atmosphere to remove it (and it might in the meantime bring down some

    If (heh) having a conductive element extending out that distance didn’t bring down the wrath of the ionosphere in a planet-sized lightning bolt, or something else we haven’t imagined. Remember those tether experiments.

    Basically I think it’s clear no one managed to successfully imagine the results of even the very simplest geoengineering humanity could accomplish — changing the level of CO2 by a few hundred parts per million.
    Nor the second simplest — inventing chlorofluorocarbons.
    Nor the interaction of the two.

    And people imagine we could rush into a far more complicated intentional change, without mucking up?

    Remember the Fermi Paradox. The odds are that we are right on track as a species to do what all the others ahead of us have done with their own planets. And it’s awfully quiet in the universe.

    Comment by Hank Roberts — 24 Aug 2008 @ 7:45 PM

  91. Andrew (a different Andrew than me) wrote: “W. Edwards Deming, the great statistician and management theorist, showed that a lack of understanding of a system led invariably to its tweaking.”

    Could you for example explain how our lack of understanding of a unified theory of gravity and quantum mechanics has led to tweaking of the universe?

    Deming is the guy who was credited for remaking the Japanese economy, figuring prominently in books celebrating the success of that economy. On the other hand, the issue of the 1990 “Kingdom of Denmark Nikkei Put Warrants” (which will Google easily enough if you are not familiar with those), pretty much sums up the “value” of all that management science the Japanese avidly sponged up at Deming’s knee. The Nikkei 225 closed 1990 at 38,916, and hasn’t been above 30,000 since July of 1990, and hasn’t been above 20,000 since March of 2000.

    Just put me down as a management theory skeptic, if not outright management theory denialist.

    Comment by Andrew — 24 Aug 2008 @ 11:23 PM

  92. Hank, the most credible way I see to reduce emissions is to wait for peak oil, natural gas and coal to kick in. As far as I am aware, only Dave Rutledge of Cal Tech has looked at the implications of fossil fuel limits on atmospheric GHGs.

    But alas, this even with a peak of 440 ppm co2, we are already overheated and I seriously doubt geoengineering would do what is required fast enough–get the atmosphere back to ca. 290 ppm co2.

    Even so, I would like to know how a combination of methods (no silver bullet) might add up. I haven’t read the paper you mention but am curious if they modeled a future with peak oil, etc. included or do they use the SRES scenarios?

    Comment by Jason — 24 Aug 2008 @ 11:53 PM

  93. See #54.

    Geo-engineering via:

    a) Continual atmospheric aerosol injection
    b) Putting mirrors in orbit

    lessen the amount of sunlight reaching the Earth, and do nothing to reduce CO2 issues.

    Can someone who is keen for either of give me some pointers to explain why the costs (in $ and energy) for those are *less* than the sorts of things that one of the world’s top energy-efficiency experts says we can do on Earth? You have to count the losses from having less sun for solar power and less sun for crops, and (maybe) for acid rain damage. I’d much rather:

    – absorb sunlight usefully where possible
    – reflect it where not, and thus raise the albedo of Earth at selected places

    *Please* look at that Art Rosenfeld piece. Is there some reason we must chase energy-expensive schemes with negative side-effects when there is a lot of low-hanging fruit that actually *saves* energy?

    Comment by John Mashey — 25 Aug 2008 @ 12:24 AM

  94. Timothy Chase, 85, I didn’t mean to suggest that article was in any way authoritative, just interesting to see how some folks think, and how the science gets muddled as it gets into the public arena. I guess the 2012 date is possibly intended to alarm and catch the eye to get readers. It worked on me that way :-)

    Thanks for posting the Robock link, Hank. If there’s a possibility of messing up the Asian and Indian monsoons, that rules it out, IMO.

    However, having been fervently anti-nuclear, I’d be willing to reconsider in the light of Blees and Hansen’s suggestions, if, IF, the waste problem and uranium mining problems were solved.

    But what if we end up with nuclear and coal and oil and renewables, wind, solar, geothermal, etc ? I remember people saying tv would kill the book, then cassettes and CDs, would replace the book, then computers…we seem to end up using all of them…the demand for lavish use of energy seems insatiable.

    In principle, we could have international treaties to ban the use of dirty fuels, but in practice, e.g. limiting nuclear weapons, protecting forests, oceans, rivers, CITES, etc, have rather limited record of success.

    We don’t seem to have a choice between good and bad, just bad or even worse.

    What if China, or USA, or Russia decide unilaterally to place some substance into the stratosphere or whatever ? I guess the rest of us will just have to accept the results, however awful and misconceived, just as we have to accept the results of ozone hole, rising sea level, and vapour trails from aircraft overhead.

    Comment by CL — 25 Aug 2008 @ 4:34 AM

  95. CL, you might want to reread Gavin’s opening post for this thread where he brought up Robock.

    Comment by Hank Roberts — 25 Aug 2008 @ 7:08 AM

  96. People are throwing out a lot of advanced concepts here without a lot of thought about feasibility.

    Sulfate injection–at best, this is a temporary solution. Aerosols decay on a timescale of months to years. CO2 keeps on giving. Aerosols decrease incident visible light and do nothing about IR–visible light’s a pretty useful commodity.

    Sun shield at L1–This is not a trivial proposition. First, it would have to orbit L1-so it’s not 100% stationary. Second, it would have to have sufficient propellant and guidance to maintain position and attitude even as it intercepted a significant amount of solar wind, light, etc. Third, the closest to this we have in current proposal is the sunshield for the James Webb Space Telescope. This is bleeding edge technology, and the scale of the L1 sun screen would be much larger. Fourth, radiation could be a siginificant life-limiting issue. Finally, again, we’re making the trade–visible light for IR. Not a good trade.

    Space Elevator–ain’t gonna happen. First, the center of mass of the elevator has to be at geostationary orbit. Not only does this require exceptionally strong fibers, the whole thing has to pass right through the radiation belts–again likely limiting lifetime and safety of the concept. I’ve never seen a satisfactory treatment of these issues–especially radiation. As far as I can tell, this is a pipedream.

    Climate change may demand that we embrace less than stellar strategies to buy time, and the longer we delay, the poorer our options become. Still, the best options we have at present remain conservation, increased use of renewables and low-tech ideas like biochar.

    Comment by Ray Ladbury — 25 Aug 2008 @ 7:25 AM

  97. Yes, Hank, you’re right. Silly of me. I’m actually trying to read everything on this site, to catch up on what’s been said since the beginning. It’s quite a lot ! Main question in my mind at this instant, why some think Lovelock’s Gaia is teleological ? Seems to me, Daisyworld is no more teleological than Darwin. The division between biology and geology, (life and non-life) is in our heads, an intellectual convenience we overlay upon reality. The way all the systems inter-relate, e.g. Great ocean conveyor, sequestration, etc,- looks very much like physiology to me, just that we don’t yet have any conceptual frame (e.g. other similar planets to compare) that permit deeper understanding of what Earth actually is…I’m rambling :-)

    reCaptcha, ‘success shivering’

    Comment by CL — 25 Aug 2008 @ 8:06 AM

  98. My engineering project only requires us to change the way people behave — special interests acknowledge our common bonds, ordinary folk willingly perform long-term sacrifices to mitigate incompletely understood consequences, etc.

    In short, I think we’re going to get the full measure of whatever it is that AGW has in store.

    captcha: Croker Emporium
    (I didn’t know captcha was a Michael Caine fan.)

    Comment by Jeffrey Davis — 25 Aug 2008 @ 8:45 AM

  99. Should we be more worried about earlier melting of methane hydrates in the shallow parts of the Arctic Ocean ?

    Comment by Colin Forrest — 25 Aug 2008 @ 1:19 PM

  100. Ok, sun screen at L1 is out. (Good!)

    Now lets get moving on useful ideas, such as biochar, producing lots of top soil, sequestering carbanacous materials deep underground, burning torrified wood instead of coal.

    {Capcha says “Mount leveled”. Must have recently visited Appliachia.]

    Comment by David B. Benson — 25 Aug 2008 @ 4:19 PM

  101. #88 – David Benson,
    Actually my #87 doesn’t imply there are any bad effects from a sunscreen at L1; but an obvious problem is geopolitical: if you can put a sunscreen there, who decides how much light is blocked, and on what schedule? Could it not be adapted for use as a weapon?

    #94 – CL,
    Actually, the ozone hole – or rather, the reaction to it – provides the best grounds we have for optimism about international agreements to curb AGW: the Montreal Protocol.

    Comment by Nick Gotts — 25 Aug 2008 @ 5:00 PM

  102. > on what schedule? … adapted for use as a weapon?
    Nick, read Teller’s piece and look for later work citing it. This is an idea that would produce a slight overall dimming. It’s not a steerable shadow. Remember how big around the Moon’s shadow is during an eclipse? This is nothing at all like that size, no central dark spot at all. There’s no schedule or selectivity possible, from the geometry involved.

    Comment by Hank Roberts — 25 Aug 2008 @ 7:06 PM

  103. A fairly new blog from one of my longtime favorite publishers has attracted seriously interesting posts by a variety of authors.

    Relevance here: ‘alternatives to geoengineering’

    Good writing. Recommended reading.

    Comment by Hank Roberts — 25 Aug 2008 @ 8:00 PM

  104. haven’t read through the comments yet, just wanted to quick mention/ask something…

    Over geologic time, chemical weathering of silicate rocks that contain Ca,Mg, and other cations, allows for the inorganic portion of that part of the carbon cycle that takes CO2, ultimately from rocks, and puts it back into rocks.

    While CaO is generally (as far as I know) produced from CaCO3, releasing CO2 in the process, I wonder if silicate minerals of the CaSiO3 (or more generally, … well, you get the idea) sort might be used to sequester carbon, speeding up the chemical weathering process. How much energy does it take to grind up typical igneous rocks? As long is the rock is ground up in the process, maybe some mining could be done, offsetting the money and energy costs of CO2 sequestration – maybe the Si could be used for solar cells, etc… and glass for mirrors… some of the mineral dust might be released into the air where it may have an aerosol cooling effect – it would buffer rather than add to acid rain, and would mitigate ocean acidification – tropospheric dispersal could allow for strategic release over the ocean without affecting land areas (perhaps too energy intensive given the short tropospheric residence time, but this aerosol cooling is not the sole purpose – it would take CO2 out of the atmosphere and/or reduce ocean acidification – or releasing it directly to the oceans would replenish the ocean’s ability to take up more CO2 ??) … Anyway, I’m not advocating we rely on this (risks and all that) – solar power looks cheap compared to oil right now anyway – but I just wanted to throw the idea out there. Basically I am wondering how energy intensive grinding up rock is. It can’t be too intensive for coal, or else it wouldn’t be useful as an energy source – but I’m guessing coal is a bit softer than granite or basalt (or andesite or syenite or gabbro or diorite…).

    — actually, on that aerosol cooling thing – maybe it could just be put on top of the obsolete oil platforms (obsolete except for being retrofitted with wind turbines) and the wind could scatter it.

    — Also, nanoparticle-TiO2 coated tarps could raise surface albedo and perhaps catalyse the oxidation of CH4 as the wind blows over it – well, that’s a bit farfetched perhaps.

    Comment by Patrick 027 — 25 Aug 2008 @ 10:38 PM

  105. Of course there’s coal gassification combined with fuel cells to boost efficiency. And using the waste heat. But whatever happennned to MHD? Did it not pan out?

    I advocate turning coal strip mines into solar farms (West Virginia could be a solar state? – not that I want more mountains to be flattened). I’d suggest storing solar heat in coal tunnels but maybe that’s too dangerous! Although maybe compressed air…??

    Comment by Patrick 027 — 25 Aug 2008 @ 10:44 PM

  106. Very little has been said about the idea of creating more marine stratocumulus clouds over the ocean, to increase planetary albedo. A temporary temperature not CO2 concentration fix, but it might buy us some time. Seemingly a fine aerosol of seawater droplets would do the trick…not as dangerous or irreversible as shooting millions of tons of SO2 into the stratosphere.

    I’ve put some papers up at


    Comment by Colin Forrest — 26 Aug 2008 @ 2:06 AM

  107. (104) Patrick 027 Says:

    “Basically I am wondering how energy intensive grinding up rock is. It can’t be too intensive for coal, or else it wouldn’t be useful as an energy source – but I’m guessing coal is a bit softer than granite or basalt.”

    Using the Mohs scale of hardness (which is an ordinal scale), coal varies from around 1.0 (lignite) to 3.0 (anthracite) to 5.5 (bituminous).

    Igneous rocks tend to be much harder, with basalt ranging from 6.7 to 7, and granite averages 7.0.

    On the whole, igneous rocks have about the same hardness as quartz or glass.

    {Capcha says “workable mouth.]

    Comment by Jim Eaton — 26 Aug 2008 @ 2:38 AM

  108. … wondering how energy intensive grinding up rock is.

    See comment 80.

    It can’t be too intensive for coal, or else it wouldn’t be useful as an energy source

    Gross electrical yield, if it were as hard to powder as hard rock, ~2000 kWh/tonne; net of pulverization, 1950-1975 kWh.

    Comment by G.R.L. Cowan, H2 energy fan 'til ~1996 — 26 Aug 2008 @ 9:12 AM

  109. Apropos the Arctic soil carbon store:

    Global warming time bomb trapped in Arctic soil: study

    PARIS, Aug 24 (AFP) – Climate change could release unexpectedly huge stores of carbon dioxide from Arctic soils, which would in turn fuel a vicious circle of global warming, a new study warned Sunday.

    And according to one commentary on the research, current models of climate change have not taken this extra source of greenhouse gas into account.

    Scientists have long known that organic carbon trapped inside a blanket of frozen permafrost covering one fifth of the world’s land mass would, if thawed, release greenhouse gases into the atmosphere.

    But until now they simply did not have a good idea of how much carbon is actually locked inside this Arctic freezer.

    To find out, a team of American researchers led by Chien-Lu Ping of the University of Alaska Fairbanks examined a wide range of landscapes across North America.

    They took soil samples from 117 sites, each to a depth of at least one metre, in order to provide a full assessment of the region’s so-called “carbon pool.”

    Previous estimates of the Arctic carbon pool relied heavily on a relative handful of measurements conducted outside of the Arctic, and only to a depth of 40 centimetres (15.5 inches).

    The study, published in the British journal Nature Geoscience, found that the stock of organic carbon “is considerably higher than previously thought” — 60 percent more than the previously estimated.

    This is roughly equivalent of one sixth of the entire carbon content in the atmosphere.

    And that is just for North America. The size and mix of landscapes in the northern reaches of Europe and Russia are about the same, and probably contain a comparable amount of carbon-dioxide producing matter currently held in check only by the cold, the study said.

    And the danger of a thaw is real, note climate scientists.

    Comment by Jim Galasyn — 26 Aug 2008 @ 12:20 PM

  110. Re 55 iron fertilization of HNLI open ocean waters – it does cause massive phytoplankton blooms – 100X the biomass, turns the water green enough to see by satellite – but much of the carbon taken out of the atmosphere gets returned by decay/respiration as it moves up the food chain, and much less gets sequestered with the detritus that rains down to the deep ocean, taking the iron with it. It’s not the magic bullet once thought. google “ironex” to find more detail.

    On another kind of geoengineering – what would be the effect of placing windmills in the arctic to spray a fine mist of ocean water when the air temperature is low enough during the winter to freeze it out into salty slushy snow? The idea would be to raise the air temperature so it would radiate away the excess heat absorbed by summertime open ocean, and create more wintertime ice/snow to insulate the methane hydrates and permafrost through the summer. Spreading salty snow over the arctic & adjacent land probably isn’t ecologically sound, but it might be better than runaway methane releases. My gut feeling is that by the time we have the sociopolitical wil to do something like this, it will be too expensive & too late.

    Comment by Brian Dodge — 26 Aug 2008 @ 6:33 PM

  111. Re 107,108,80,77


    “Some discussion here has referred to the olivine dispersal idea “…

    Well, I guess I should go back and read more – that sounds like what I was thinking of…

    Comment by Patrick 027 — 26 Aug 2008 @ 7:13 PM

  112. “The system is our planet’s biosphere, and tweaking it may very well lead, as Deming warned, to sub-optimization, decay, and the eventual destruction of the system. The fact that such ideas as geo-engineering are being given such serious discussion is troubling.”

    I agree, Andrew. The thought of it scares the hell out of me, especially the thought of artificially removing CO2 from the atmosphere. The consequences of removing too much would not be fun, since all chlorophyll-based plant life relies on it, and no plants = no life. The cure could be much worse than the disease.

    Comment by Tracy — 27 Aug 2008 @ 3:52 PM

  113. Tracy (112) — It is thought that humans have so far added an excess of 500 GtC to the active carbon cycle. That is a lot to remove so I’m certainly not concerned about removing too much.

    Comment by David B. Benson — 27 Aug 2008 @ 4:31 PM

  114. Tracy, where do you get the notion it would even be possible to remove “too much” CO2 from the atmosphere?
    Is that something you read someone suggests?

    Have you had high school chemistry? That would reassure you. You know how gas bubbles out of a carbonated beverage when you open it? That’s because the amount dissolved in the liquid is out of balance with what’s in the air around it.

    If somehow we had a huge outbreak of plants and ferns and mosses and lichen taking over the world and sucking up all the CO2 from the atmosphere — well, that would be returned as soon as any of it died naturally, but the oceans would be releasing CO2 even faster.

    Seriously, this isn’t something that can happen on the human time scale. Where did you get the idea from?

    Comment by Hank Roberts — 27 Aug 2008 @ 6:43 PM

  115. Gavin,

    You concluded:

    Recently I heard geo-engineering likened to climate change methadone – an emergency treatment to substitute one addiction (carbon emissions) with another. This seems rather apt, and like the analogous situation with heroin, methadone isn’t going to be a cure.

    Shouldn’t you have written “…, geo-engineering isn’t going to be a cure.”?

    Heroin addicts only recover when they accept what they are doing to themselves, and even then many continue on to a squalid death.

    We, like most heroin addicts, still seem to be in a state of denial. If geo-engineering is not the answer, can you provide any hope?

    Cheers, Alastair.

    Comment by Alastair McDonald — 28 Aug 2008 @ 4:56 AM

  116. #114 Hank Roberts
    If somehow we had a huge outbreak of plants and ferns and mosses and lichen taking over the world and sucking up all the CO2 from the atmosphere — well, that would be returned as soon as any of it died naturally, but the oceans would be releasing CO2 even faster.

    As I said in my brief (experimental, first) post, the key word was artificial. An outbreak of plants and ferns (hell, even triffids, why not :)) is fine by me. I’d rather it was an outbreak of trees since they’d store it for considerably longer. And er, plants respire too and produce CO2, they don’t just release it on decay, but I’m sure you know that!

    Seriously, this isn’t something that can happen on the human time scale. Where did you get the idea from?

    Where did I get the idea from? It’s that scary word geo-engineering, which after all means a quick technological fix that will achieve results within the human timescale.

    What’s the problem? Too much CO2 released into the atmosphere (which isn’t being absorbed, obviously, since CO2 levels have increased to what, approx 380ppm?) – therefore, the ‘simplistic’ technical solution is to remove it from the atmosphere, rather than prevent it from being produced in the first place. But yes, OK, the oceans will counterbalance – forgive me my stupidity – serves me right for posting late at night (and yes, actually, I do have A level chemistry, thank you)

    But OK, you’ve reassured this ignoramous that on a human timescale, removing more than 500+ GtC from the atmosphere isn’t feasible.

    Hey, I read this site to learn :) I know, you’re all scary climatologists who leap on us lesser mortals if we dare dip a toe in the climate change debate but you really need to do better at interpreting your data for a wider audience (not necessarily here, I know, you have no wish to dumb down, this is supposed to be about science, not politics etc). Because the Skeptics do a bloody good job at interpreting theirs! Unless you don’t want to win the battle for hearts and minds?

    Comment by Tracy — 28 Aug 2008 @ 8:50 AM

  117. Chuckle. The real climatologists are usually identifiable, and the Contributors who make the site happen are listed in the sidebar.

    Me, I’m just another reader, and I agree. Try interpreting in simple words as you understand what’s being written by the scientists — they’re good at telling folks like us when we get it right, get it wrong, or ask good questions.

    Comment by Hank Roberts — 28 Aug 2008 @ 2:59 PM

  118. Tracy (116) — Actually, removing the excess 500 GtC from the active carbon cycle can be done in less than a century by sequestering deep underground carbonaceous meterials such as biochar and torrified wood. The cost is about 15 of the world’s gross product during that interval.

    Comment by David B. Benson — 28 Aug 2008 @ 5:10 PM

  119. It seems to me that the geoengineers are only substituting one kind of pollution for another kind of pollution. So2 for Co2. Much as oil substituted for coal. Or Freeman Dyson’s mutant trees.

    The total energy content of the world is constant and the total entropy is continually increasing.

    The First and second laws of thermodynamics.

    Comment by Old Time Populist — 28 Aug 2008 @ 5:38 PM

  120. It seems to me that the geoengineers are only substituting one kind of pollution for another kind of pollution.

    That is true only if you exclude from the geoengineering category methods that directly remove CO2, such as olivine pulverization and dispersal, which can convert atmospheric CO2 to a stable solid mineral that could lie thinly over much of the world’s land surface without harm, or the above-mentioned burial of charcoal.

    Another way to look at the fear of overshoot in removing atmospheric CO2: it is possible to remove 500 GtC about as quickly as it has been added, just as it is possible for a porter in an Everest expedition to carry a load halfway up.

    Inadvertently removing far too much of it, putting the atmosphere into as unfamiliar a state as now, but on the other side of the preindustrial 280 ppm, would be like that porter’s forgetting to deliver his load at the intended camp, and instead carrying it on up to the summit.

    Comment by G.R.L. Cowan, H2 energy fan 'til ~1996 — 28 Aug 2008 @ 6:20 PM

  121. David, does this presume someone will have solved the problem of coal mine fires, since charcoal ‘mines’ would also be at the same risk, maybe more so since more oxygen would be available in such deposits? Or is the source of your numbers presuming these deposits could be kept from catching on fire in some reliable way?

    Stopping the current coal mine fires would make quite a difference to the current situation.

    Comment by Hank Roberts — 28 Aug 2008 @ 6:47 PM

  122. Re #118: Oh dear. Not 15, but 1%, one percent.

    Comment by David B. Benson — 28 Aug 2008 @ 7:16 PM

  123. Hank Roberts (121) — If properly buried, there would be no oxygen present. One could assure this by pumping in CO2, which chemically binds to coal, so I suppose also biochar and torrified wood. The biggest unknown is just how long those buried carbonaceous materials would last before re-entering the active carbon cycle via the actions of micro-organisms.

    The best, most recent, estimate I could find, from some Chinese researchers, puts the world’s coal seam fires at about 1/2% of the total excess CO2 added.

    Far more important is cement production at about 4–5% (I think) of the total:,1518,575023,00.html

    Comment by David B. Benson — 28 Aug 2008 @ 7:58 PM

  124. To return to 350ppm CO2 or less, effort and expense will be required to remove the CO2 from the atmosphere. I’m a fan of both reforestation and carbon negative power plants that use forest and agricultural residue as feed stock and CCS on the exhaust stack. We must pursue these or similar activities to return to a healthy climate and will dial back our effort and expense as we approach the final CO2 target, with no chance of overshoot.

    My fear is that we craft a solution that we cannot control. One speculation is that the desire for a high yielding alga for bio fuel farming will lead to a genetic engineered monster, an alga that will use the C4 pathway for increased photo-efficiency and some type of altered oil content that will resist decay to allow for maximum yields. If a cell that nature has not seen before is developed and introduced on land or sea, under the best of intentions, we may have a green slime that cannot be controlled. We don’t need a synthetic cellular Kudzu.

    Comment by john ramming — 29 Aug 2008 @ 2:41 AM

  125. CO2 to cement:,1518,575023,00.html


    Comment by Arch Stanton — 29 Aug 2008 @ 9:04 AM

  126. > CO2 to cement.
    Hopeful; much covered:
    Tests haven’t been done yet. Time will tell.

    I’d think that eliminating all traces of salt from the product is important. I recall Berkeley has lots of old crumbling foundations made with ordinary concrete but using sea water, a century ago.

    Nowadays with rebar in concrete, corrosion is also a concern. Moss Landing is using gas as fuel, not coal, so their stack exhaust gas is far cleaner. Getting clean CO2 out of a coal plant is already a challenge (especially since the Clean Air Act is under so much attack and industry doesn’t _want_ clean coal exhaust, see the mercury rulemaking challenges).

    Comment by Hank Roberts — 29 Aug 2008 @ 10:30 AM

  127. >Much covered (elsewhere)
    True, but I was curious about what folks here had to say.
    As always, thanks for your thoughts Hank.

    Comment by Arch Stanton — 29 Aug 2008 @ 11:08 AM

  128. John, if you’re worried about the uncontrolled propagation of algae, we’re already very deeply into that scenario. Ocean dead zones, driven by nutrient runoff, are expanding globally; it’s sometimes called “the rise of slime” by oceanographers. The metabolic products from these algae are often neurotoxic and threaten coastal wildlife and humans.

    Comment by Jim Galasyn — 29 Aug 2008 @ 11:33 AM

  129. Jim thanks for the feedback. The conditions you describe are already underway, but they are reversible. Dead zones can retract if we reduce the nutrient runoff, increasing cost of energy and fertilizer will push us in this direction. Will we have the wisdom to be proactive and do more? Even the deep ocean becoming anaerobic can be reversed with great effort. If we allow our warming climate to go so far that it causes the shutdown of deep ocean currents responsible for maintaining oxygen levels for aerobic life, a MAJOR effort to reduce atmospheric CO2 could lead to the restarting of the deep ocean currents. Future generations may have no choice but to expend that MAJOR effort with the only alternative facing them being extinction. As hard as it may be to develop CCS, it is trivial compared to what the future will face if we do not face this AGW challenge in our own generation.

    Comment by john ramming — 29 Aug 2008 @ 1:14 PM

  130. Jim, my final thought did not get appended to the last post. My concern is that a genetically engineered “solution” may have severe consequences that are not reversible under any circumstances.

    Comment by john ramming — 29 Aug 2008 @ 1:17 PM

  131. This is the sort of surprise we have to expect — a change that slows down as temperature increase:

    ______excerpt follows_______

    The paper, published in a special edition of the Proceedings of the National Academy of Science, showed for the first time ….

    “The chemical details of how the atmosphere removes nitric acid have not been clear,” Francisco says. “This gives us important insights into this process. Without that knowledge we really can’t understand the conditions under which nitric acid is removed from the atmosphere.”

    An unusual aspect of the molecule helped it escape detection by scientists. The reaction involving this molecule proceeds faster as you go to lower temperatures, which is the opposite of most chemical reactions,” said Lester. “The rate of reaction also changes depending on the atmospheric pressure, and most reactions don’t depend on external pressure. The molecule also exhibits unusual quantum properties.”

    Comment by Hank Roberts — 29 Aug 2008 @ 4:01 PM



    Comment by Julian Flood — 30 Aug 2008 @ 5:30 AM

  133. David B. Benson #122:

    Oh dear. Not 15, but 1%, one percent.

    Eh, your typo is a classic :-)

    Comment by Martin Vermeer — 30 Aug 2008 @ 11:45 AM

  134. Does a low mean temperature help anyone if the poles stay warm and only the equatorial regions cool?

    Comment by Lab Lemming — 2 Sep 2008 @ 8:31 PM

  135. I hope now most reasonable people realize that natural greenhouse gas emissions from melting permafrost will soon overwhelm any cuts we make (i.e. any carbon dieting scheme is unfeasible):

    “…Researchers were investigating “alarming” reports in the last few days of the release of methane from long frozen Arctic waters, possibly from the warming of the sea…” –“Arctic sea ice drops to 2nd lowest level on record,” AP, 27 Aug ’08

    A frozen peat bog in western Siberia the size of France and Germany put together contains about 500 billion tons of carbon. Western Siberia has warmed faster than almost anywhere else on the Earth, with an increase in average temperature of about 3C in the last 40 years. More than half the land covered by the topmost layer of permafrost will probably thaw by 2050.

    There is even more Siberian permafrost is under the ocean, an area six times the size of Germany containing about 540 billion tons of carbon. That submarine permafrost is perilously close to thawing. Three to 12 kilometers from the coast the sea sediment is just below freezing. The permafrost has grown porous, there is a loss of rigor in the frozen sea floor, and the surrounding seawater is highly oversaturated with solute methane.

    “If the Siberian (submarine) permafrost-seal thaws completely and all the stored gas escapes, the methane content of the planet’s atmosphere would increase twelve fold. The result would be catastrophic global warming.” –“A Storehouse of Greenhouse Gases Is Opening in Siberia,” Spiegel, 17 April ’08

    Please excuse me for repeating myself, but there is a very inexpensive simple way to immediately cool the Earth: just put a small amount of aerosol into the air to dim the sun. We won’t be able to stop rapid ecosystem collapse without geoengineering. Soon melting permafrost will overwhelm any cuts we make to our emissions.

    Comment by Brad Arnold — 3 Sep 2008 @ 5:45 AM

  136. Brad Arnold, While I agree that the potential for outgassing from permafrost and clathrates is a serious concern, let me get this straight: You suggest that we should give up on controlling carbon outputs, despite:
    1)outgassing of ghgs will be a gradual process at first
    2)aerosols will have an effect lasting at most a few years
    3)we don’t understand all the possible side effects
    4)CO2’s influence on climate is one of the best understood, while aerosols remain among the least certain.

    That about got it? Excuse me, but wouldn’t it make more sense to play around with terraforming other celestial bodies first before mucking around with the only one we know can support life?

    Comment by Ray Ladbury — 3 Sep 2008 @ 7:58 AM

  137. I’m surprised that the same governments that blindly speak of carbon taxes and emission targets do not also talk of simple changes to building codes (for example). If every house and building had nice white roofs we would all save on electricity bills in summer and also greatly reduce the amount of IR conversion. OK it would would look funny to see every house with a white tiled roof, walls and patio etc but if we all knew it was saving us money as well as helping to save our climate we would gladly embrace it. On the other hand a new big tax…Collectively we need to start thinking of using a myriad of simple solutions and right away because it doesn’t appear that a new climate zero energy source capable of replacing fossil fuels is coming any time soon.

    Comment by David xke — 5 Sep 2008 @ 8:58 AM

  138. I believe that increasing the albedo of low lying clouds has been seriously suggetsed and a solution proposed. In essense unmanned ships would use wind power to seed clouds by pouring water vapour into the air. Apparently it has the backing of two climate modelling teams and could keep the climate stable for decades.

    Comment by pete best — 5 Sep 2008 @ 11:54 AM

  139. There is little probability that governments and industry will ever agree to serious carbon emission reduction plans. No one will seriously do anything until its almost to late.

    And then you are only left with geoengineering on funding scale that makes WWII look like a school lunch money. It would be far better for serious climate scientists and those environmentalists who dont subscribe to , 500 milion people in pre industrial society ideal, to seriously consider geoengineering options and study them in time to be able to give serious proposals to governments and industry 20-30 years from now when it finally becomes impossibly to ignore AGW and climate change.

    Comment by Aleksandar — 15 Sep 2008 @ 12:36 PM

  140. “No one will seriously do anything until its almost to late.”

    IMHO, that is where we are now. 2008. Almost too late.
    I agree, at some point, there will be an obvious upheaval of some kind, a trigger that panics the masses, and the shockwave to the politicians and CEOs and public will cause such alarm, that there will be a huge flurry of action, and it will be ill-considered, and counter-productive, and make matters even worse.

    ‘wanted territory’

    Comment by CL — 15 Sep 2008 @ 3:18 PM

  141. I am interested if there was rapid brief SO2 increase in March-April and July-August 2008 that might have caused the slumps in the global temperature possitive anomaly compared to the previous months,which can be seen from here by clicking on the wanted month. The drop in the temperatures is mostly due to cooler lands and it is clear because of the property that it warms and cools easier and faster than the water.I know that in March there was volcano eruption in Kamchatka,Russia region and in July in Alaska .It is clear that equatorial volcano event is more influential to the global climate than polar but the first case is followed by significant cooling of the Siberia after the warmest March there and this SO2 might have resided westwards due to typical East winds in this region In addition it is strange that in both cases SST in Nino region,which is belived to be the main reason for the short time fluctuations of the global temperatures, were slightly increasing and no other shear reason for these slumps can be found .
    In spite of searching the google neither I can find paper containing statistics for every recent volcanic activity and the quantity of SO2 ,nor any statistical graphics for the mean global SO2 consentration in ppm simular to those which are available fot the CO2.I would like to answer if someone knows a link for such data

    Comment by UnknownBG — 18 Sep 2008 @ 3:41 PM

  142. If somehow we had a huge outbreak of plants and ferns and mosses and lichen taking over the world and sucking up all the CO2 from the atmosphere — well, that would be returned as soon as any of it died naturally, but the oceans would be releasing CO2 even faster.

    Comment by SecularAnimist — 15 Oct 2008 @ 7:36 PM

  143. It all comes down to economics and politics. The graphs persons in special interest funded research is somehow far more linear, less complex and leads to a conclusion that geoengineering would solve most of not all of our problems. For one it is difficult to predict long term trends and SO2 is not a good replacement either. The intermediates could pose problems, and the threats to human health, lung disease, COPD and asthma are of concern. Currently only small fighter jets can get to the stratosphere and they cannot get enough S02 there to make a difference. Funding into this type of project could prove still quite expensive.

    Geoengineering with plants, bacteria and some plankton could provide more realistic and safe alternatives. Think about it, it is just basic chemistry, we could harnass carbon dioxide and capture carbon and increase plant biomass as well.

    Comment by jcbmack — 5 Nov 2008 @ 12:09 AM

  144. A little known option for removing carbon from the atmosphere is to collect, ship and dump agricultural (and commercial forestry) residues to the deep sea for long term burial.

    A recent publication on this claims high efficiency and immediate availability, based on existing technology. Admitedly some further research would be needed.

    Basically, this just might close the anthropogenic carbon cycle causing our problem.

    Comment by Pekka Kostamo — 31 Jan 2009 @ 2:57 AM

  145. Hat tip to:

    “… After a series of moderate succeses over the past decade, it seems that the idea of sequestering CO2 in the oceans might truely be dead and buried. Project LOHAFEX, a joint Indo-German group, succeeded in seeding an area of 300km2 with over 6 tonnes of iron, resulting in a doubling of plankton biomass in just two weeks. What the team didn’t factor was the power of the ocean’s food web. Instead of the plankton bloom undergoing a natural death and sinking to the ocean floor (along with the sequestered CO2), the phytoplankton became an instant food source for hungry copepods, who in turn were consumed by a swarm of larger crustaceans (amphipods – see inset picture).

    This ‘grazing effect’ was apparently absent from previous experiments, which instead stimulated the growth of diatoms. Diatoms differ from most phytoplankton in that they are protected from being eaten by protective shells made of silica. Whilst the experiment did succeed in providing new insights into the dynamics and ecology of plankton, to quote Ken Caldiera ‘I think we are seeing the last gasps of ocean iron fertilisation as a carbon storage strategy’.”

    Comment by Hank Roberts — 6 Jun 2009 @ 9:21 PM

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