Gee-Whiz Geoengineering

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

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

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

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

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

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213 comments on this post.
  1. Max Wyvern:

    As a member of the Mars Society for the last several years, I’ve heard much talk of “terraforming” Mars to make it a warmer and wetter world suitable for human habitation. This notion is extremely controversial withing the Mars settlement advocate community; there being a split between ‘greens’ who love the idea, and ‘reds’ who hate it. Aside from the value or detriment of such a project’s effect on its target planet, a side benefit may be to learn a fair amount about what could possibly be done to Earth to produce the opposite effect; to ‘areoform’ our planet so to speak (although the goal is not to go so far as to create another Mars).

  2. Figen Mekik:

    To Caldeira’s credit he does say “This is not to say we should give up trying to reduce greenhouse gas emissions.”

    But, being from Ankara, Turkey, this idea really bothers me. I grew up there and Ankara is geographically in a large basin surrounded all around by mountains. And there’s lots of coal in Turkey so that’s what we used to burn, and talk about thermal inversion and ominous black skies!! We had to wear uniforms to school and I remember my white sleeves turning not gray or brown but black! by the end of the school day. And black water washing off my face when I got home and tried to clean up. Even as a 12 year-old I remember thinking if this is the soot that’s clinging onto my face and clothes in one day, what’s happening to my lungs?

    So burning coal was outlawed in Ankara, and we imported lots and lots of biogas from the then Soviet Union. But the air literally cleared! Fast. Sure, burning methane (biogas) produces a lot of CO2, but coal produces a lot of CO2 and soot! So if you have to pick the lesser of two evils…

    I realize it isn’t the same thing to have soot at eye level and injecting aerosols into the stratophere. And they will probably do this in the middle of the ocean or something far from people; but I find it ethically paradoxical to fight pollution with more pollution.

  3. Mark A. York:

    I sure hope so Ray. This follows a Wall Street Journal article I pasted here somewhere arguing for the same thing, by Reagan’s former assistant defense secretary in charge of star wars. It’s the same old do anything except stop the gas approach. How nice the NYT has followed suit with pie-in-the-sky op-ed’s. Expect more.

    We have some serious aerosols around here in LA now. They blotted out the sun two days ago in the afternoon. It was cooler, but eerie, like a nuclear winter.

  4. Walt Bennett:

    Oh but the scary part is that some will grab hold of this nightmare and proclaim: “Problem? What problem? I got yer solution right here…”

    Are we doomed to perish from our own collective madness?

  5. Paul Dietz:

    I am more concerned that some misplaced sense of squeamishness will lead to solutions like these being underinvestigated, when they may turn out to be necessary. Can you guarantee that CO2 emissions will be reduced enough, or even sincerely claim that it is likely the world will get its act together and reduce them enough?

    If not, then don’t be obstructive.

  6. J.C.H.:

    Any country could unilaterally do this sort of thing. I’ve even heard it suggested as a weapon.

    ” Stop stealing our sunshine or we’ll bomb you back to the stone age.”

  7. Steven T. Corneliussen:

    The highly similar WSJ op-ed piece that Mark A. York mentions was surely “Thinking Big on Global Warming” by Fred C. Ikle and Lowell Wood on Oct. 15. And just as Figen Mekik, above, points out that the NYT piece “does say ‘This is not to say we should give up trying to reduce greenhouse gas emissions,'” the WSJ piece said, “Clearly, we need both: adequately explored geo-engineering options for contingent climate stabilization, and truly effective, practical measures to reduce emissions of greenhouse gases.” Please note, though, that the WSJ piece also said: “But beware. Do not try to sell climate geo-engineering to committed enemies of fossil fuels. Although several geo-engineering options appear to be highly cost-effective, ideological opposition to them is often fierce. Fashionable blogs are replete with conspiracy theories and misinformed attacks. Because of this intimidating opposition, no serious geo-engineering research programs have been started.” I suppose that means that some writers of WSJ op-eds would call RC a “fashionable blog” that’s conspiratorially impeding research. That’d be easier to believe if it didn’t come from an op-ed page where the fashion used to be to declare it impossible that humans could affect climate at all, but where the fashion now is to declare that we can outright engineer it.

  8. Anders Lundqvist:

    When it comes to climate issues, it seems to me that noone can guarantee anything until after the fact. I am a computer programmer, not a climate expert, but what I do know is that the more variables you throw into your program, the more unexpected things are going to happen. And those unexpected things are never the things you want to happen. So please – no more anthropogenic variables in the atmosphere!

  9. Thomas Lee Elifritz:

    The main problem that I have with the anti space crowd, is that they utterly fail to understand that the pursuit of a space based solar power satellite solution (as opposed to sunshade solution) will very likely generate the scientific and technological maturity which will enable us to chemically engineer ourselves out of the problem on the ground, at the source.

    The key term is ‘space based’. In the beginning we won’t be beaming energy back to Earth, we will be trying to figure out what to do with at the source – in space.

  10. Tom Geauvreau:

    Covering a problem with another problem is hardly a solution…

  11. Nigel Williams:

    Well, we better hurry, either way!

    Another variable with possibly unexpected consequences has been discovered – wind strength on the southern ocean. This, combined with continued growth in emissions is making bad rapidly worse.

    Unexpected Growth In Atmospheric Carbon Dioxide

    ScienceDaily (Oct. 23, 2007) — A team of scientists has found that atmospheric carbon dioxide (CO2) growth has increased 35 percent faster than expected since 2000.
    The study also states that global CO2 emissions were up to 9.9 billion tons of carbon in 2006, 35 percent above emissions in 1990…

    “What we are seeing is a decrease in the planet’s ability to absorb carbon emissions due to human activity,” Dr Canadell says.

    “Fifty years ago, for every tonne of CO2 emitted, 600kg were removed by land and ocean sinks. However, in 2006, only 550kg were removed per tonne and that amount is falling.”

    The decline in global sink efficiency suggests that stabilisation of atmospheric CO2 is even more difficult to achieve than previously thought. We found that nearly half of the decline in the efficiency of the ocean CO2 sink is due to the intensification of the winds in the Southern Ocean.”

    The Southern Ocean winds have increased in response to greenhouse gases and ozone depletion. The increase in winds has led to a release of natural CO2 stored in the deep ocean, which is preventing further absorption of the greenhouse gas.

  12. Alastair McDonald:

    You say that if we are going to continue burning fossil fuels at today’s rate or even greater, then because the life time of CO2 can be up to 1000 years, we will have to keep sending aerosols up into the stratosphere for that time. But the oil, coal and uranium are starting to run out, so how willwe be able to fuel this sulphate ejection system for the next millenium?

    OTOH, even if we stopped burning all fossil fuels tomorrow the climate would still warm, the Arctic sea ice will disappear, and the Greenland and West Antarctic ice sheets follow it.

  13. Philippe Chantreau:

    If we are going to explore (controlled) geo-engineering, there are ideas that make a lot more sense than the “Tellerian” sulfate aerosols pipe dreams. First there are many conservation measures that hold an enormous virtual supply. Only problem is, the right wingers/libertarians will freak out and unleash massive mind manipulation campaigns the moment anyone tries to pass legislation to generalize conservation measures as more than voluntary.
    So, why not systematically drill the Earth to the magma so we can generalize the use of geothermal heat? Not easy, but a lot less risky, a lot more predictable, leading to a possibly unlimited supply of totally clean electricity with the complete eradication of fossil fuel generated power. The corresponding expense might not be that much different than the gigantic subsidies expected by the nuclear industry, without all the waste and safety problems. What’s not to like?

  14. Stephen Pranulis:

    There is probably a law of human behavior that someone can cite here. Something to the effect that people tend to become squeamish or otherwise averse to the truly difficult task of challenging a culture’s norms of behavior, especially norms that may currently benefit their particular tribe or socio-economic group, even if those norms can be shown to be potentially lethal to the individual or group in the long term. To a number of WSJ readers and others, life styles or philosophies that threaten to dislodge them from their sweet spots on the pipelines of energy and wealth must be very very unsettling, enough to make them hope that deus ex machina solutions may allow them to stay at their current comfort level without any major unforseen negative consequences.

  15. Lawrence Brown:

    Actually we don’t need to go to the extremes that Mr. Caldeira suggests. Since we receive about 245 watts/m^2 at the surface after allowing for geometry and albedo, and a doubling of CO2 from pre-industrial levels increases the energy rate by approx. 4.5 w/m^2, what’s needed is to to reduce the energy received by the Sun by that amount or more. The answer is obvious, as any fool can plainly see. Move the planet further from the Sun! We’re currently at a mean distance of about 150 million kilometers away from Old Sol. If we we’re to move to about 153 million kilometers, we could reduce the amount we receive by about 10 watts per square meter, down to about 235.

    We need to be careful of course not to overshoot. We wouldn’t want to become a satellite of say Neptune, and we’d have to be prepared for the inevitable consequences of earthquakes and seismic sea waves and God knows what else that would ensue from the force and accompanying acceleration necessary to move our mass, but these are details. I write this to you from my rubber room, where other inmates have their own ideas such as salting the oceans with iron, leading to a proliferation of algae blooms and possible destruction of plankton and with consequences for life up the food chain.

    The Earth isn’t a science lab, where you can purposefully perform an experiment and then negate all the results, good and bad. As Raypierre says, we’re already conducting an experiment by burning fossil fuels, and look what we’re possibly facing as a result! Scientists and engineers surely do love to think about this stuff, but they should remain thought experiments, until something practical and cost effective comes along. Ray’s analogy of the sunshade as well as other geo-technical solutions, as a lifeboat is very effective. This lifeboat is leaking badly.

    Perhaps the worst aspect of these technical “solutions” is that they give a de-facto green light to continue to put more CO2 into the atmosphere, Since oil production is expected to peak within decades if not sooner, nations will turn more and more to coal, which as Figen pointed out in an earlier post is a very dirty fuel.

  16. Greg Simpson:

    raypierre: “The problem is that by the time we know enough to have any confidence at all in this lifeboat, CO2 may have risen to the point where the lifeboat becomes not just a backup, but a necessity.”

    Can we be so sure that we haven’t already reached this point? It at least seems plausible that our best feasible efforts could still leave us with an intolerable carbon dioxide burden. It sounds like a good idea to start studying the possible down sides to geoengineering schemes now.

    Once we effectively stop emitting greenhouse gases we should be able to sequester carbon dioxide from the air fast enough to bring it down to an acceptable level at modest cost within a few centuries. That is, if we survive long enough with our technological civilization intact.

    [Response: A proven way to extract CO2 from the atmosphere and sequester it would change a lot of things — in effect it would change CO2 from a “from here to eternity” problem into something more reversible. It would open up a few more possibilities for deferring action until the right technology is developed, and then intensively applying it. The IPCC carbon capture and storage report suggests that growing biomass and burning it with carbon capture might work, to some extent. This, too, is a kind of untested lifeboat, and it would be dangerous to count on it before it’s proven technically feasible. I like it somewhat better than the aerosol sunshade, because you only have to sequester each bit of CO2 once. You don’t have to recapture it and do it over again the next year — assuming the sequestration isn’t leaky. –raypierre]

  17. Maurizio Morabito:

    The problem with geo-engineering solutions is that we literally have no idea of what the consequences would be. When people have “tinkered with nature” in the past hoping for a quick-fix, it has invariably meant a worse disaster than the one they were trying to avoid.

    We should always keep in mind the history of the misinformed attempt to eradicate the Australian grey back beetle by importing Cane Toads from South America in 1835. With the beetles living too high to be food, the Cane Toads have been invading the whole Continent since, at rates of 5 to 50 km/year and seemingly unstoppable.

    One wonders what we would do if injecting sulphate aerosols in the stratosphere were to cause a planet-wide cooling event far beyond the original intentions

  18. Edward Greisch:

    1. Yucca Mountain is full of nuclear fuel that needs to be reprocessed. We used to reprocess spent fuel rods until 1/2 ton of enriched uranium somehow wound up in Israel.
    2. Reference:
    by Alex Gabbard
    Oak Ridge National Laboratory
    Oak Ridge, TN
    Selections from the 19th Annual Conference
    March 14,15,16, 1996
    Nashville, Tennessee

    Published by the
    Edited by Jack D. Arters, Ed.D.
    Conference Director
    The truth is, all natural rocks contain most natural elements. Coal is a rock.
    The average concentration of uranium in coal is 1 or 2 parts per million. Illinois
    coal contains up to 103 parts per million uranium. A 1000 million watt coal
    fired power plant burns 4 million tons of coal each year. If you multiply 4
    million tons by 1 part per million, you get 4 tons of uranium. Most of that is
    U238. About .7% is U235. 4 tons = 8000 pounds. 8000 pounds times .7% =
    56 pounds of U235. An average 1 billion watt coal fired power plant puts out 56
    to 112 pounds of U235 every year. There are only 2 places the uranium can go:
    Up the stack or into the cinders.
    Since a reactor full fuel load is around 11 tons of 2% U235 and 98% U238, and
    one load lasts about 10 years, and what one coal fired power plant puts into the
    air and cinders fully fuels a nuclear power plant.
    Compare 4 Million tons per year with 1.1 tons per year. 1.1 divided by 4 Million
    = 2.75 E -7 = .000000275 =.0000275%. Remember that only 2% of that is
    U235. The nuclear power plant needs ~44 pounds of U235 per year. The coal
    fired power plant burns coal by the trainload. The nuclear power plant consumes
    U235 in such small quantities yearly that you could carry that much weight in a
    3. See the rest of Alex Gabbard’s article. U238 can be bred into Plutonium and
    Thorium can be bred into Uranium. We can fuel our nuclear power plants for
    CENTURIES just by extracting uranium and thorium from coal cinders and
    4. See:

  19. Earl Killian:

    My personal opinion is that actually deploying aerosols would delay making the changes that need to be made anyway. However, I believe we must study the issue (but not by diverting existing research money) because if the ice starts to slide in Greenland or WAIS, we may find this is cheaper than trying to move cities and hundreds of millions of people and animals or building enormous levies. Still, the research should be kept in context: a desperate measure for desperate times. In that regard, it may be helpful to quote a Aldo V. Da Rosa’s textbook, Fundamentals of Renewable Energy Processes:

    “Since increased concentrations of CO2 can lead to global warming, some people have proposed increasing the emission of SO2 to stabilize the temperature because of the cooling effect of this gas. Even ignoring the vegetation-killing acid rain that would result, this proposal is the equivalent to balancing a listing boat by piling stones on the other side.”

    Indeed, should we have to resort to geoengineering, we are in a listing lifeboat.

  20. jimvj:

    The proposal of Gregory Benford et al. to pump nanoparticles with a size range that would selectively reflect UV radiation seems more seductive. About a million tons (per year?) could be fired by heavy artillery guns, or delivered by high flying planes, etc. The winds at altitude would disperse the particles very quickly.

    Since the particles have a relatively short (a few months) life at altitude, before falling back to earth, this would be akin to a small volcano erupting every few months or years.

    On the upside, this could increase plant growth rates and lifetimes at high latitudes, reduce skin cancer incidence, and cool the planet.

    On the downside, while this does nothing to neutralize the acidification of the oceans, it could give humans the false impression that CO2 is no longer a problem, and so let’s burn that coal/shale/tar as fast as we can. There is also the question of whether the nanoparticles would be health hazards, though the very low concentrations would suggest they are not.

    Is there anything in international law that would prohibit a very rich tycoon or nation from doing this unilaterally, if only to try to validate the concept?

  21. Figen Mekik:

    Please excuse the ignorance of my question but it popped into my head: wouldn’t injecting sulfate aerosols into the atmosphere produce sulfuric acid rain?

    [Response: The amount you would inject into the stratosphere would be small compared to what coal burning power plants already put into the troposphere, so the incremental effect globally on acid rain probably wouldn’t be the real problem. If the aerosols get concentrated in polar subsiding zones due to some unexpected stratospheric circulation — much as Titan’s haze congregates at the pole — that could be bad news regionally for the Nordic countries, I suppose. –raypierre]

  22. Fernando Magyar:

    Re #5, I for one intend to be as obstructive as possible to any such ideas until 1) I can be assured that they are absolutely necessary for survival. And 2) that those who are proposing such solutions have a deep understanding of the consequences. I am very much against maintaining the current status quo.

    To paraphrase Albert Einstein, you can’t solve problems with the same kind of thinking that created the problems in the first place.

    I would defer to Donella Meadows to say it better than I ever could, we need fewer, not more technological fixes:

    What we need is a paradigm shift away from our current economic model of continuos economic growth. Yeah, I know that that is heresy but what we have now hasn’t worked.

    Go to this site to see an example of what a great thing technological solutions really are, every piece of plastic floating out in the Pacific Ocean today, was an engineered solution to some problem, well it looks like they didn’t think very much about the problems those solutions would create:

    Plastic Trash Vortex Menaces Pacific Sealife: Study
    by Deborah Zabarenko

    I think anyone advocating geo engineered solutions to climate change should take a sailboat ride out into the Trash Vortex in the Pacific.

    OTH, there may be the beginning of a silver lining in Peak Oil coming a bit sooner than expected:
    The report on coal is also very interesting:

  23. Dan W:

    Prof Makik, (21) I had the same thought. However, according to some calculations in Nature (Nature 447, 132-136 (10 May 2007) a few months ago, the amount of sulfur to be sent to the stratosphere (2 million tones/yr) to cool the planet would a small amount of what we annually put into the troposphere (>100 million tones SO2/yr).

  24. Hank Roberts:

    Ray, what are these experiments doing now in the upper atmosphere?

    I know it’s a favorite of the conspiracy people, but there’s a lot of academic work published.

    I can’t believe there’s a way to prime the pump of the upper atmosphere by tickling it from the ground to increase the heat export.

    But I do wonder what they’re doing with this system now, and what the folks doing this work would think of having something like a barium sulfate cloud dumped into the upper atmosphere and how they might interact.

  25. Figen Mekik:

    Thanks Dan W!

  26. Chris:

    I’m still entirely unconvinced by the idea. I see several problems with aerosols as “offsetting” the CO2. For one thing, they aren’t completely opposite in effect so I would suspect a lot of global inhomogenities in climate. Another thing, is you just replace one problem with another- more pollution, more acid rain, still not very good for ocean chemistry and the ocean acidification problem. There is also the difference in atmospheric residence time or the fact you’d have to keep increasing aerosols as CO2 increases, and at larger rates. What if in 200 years the aerosols stop? What if a pipe breaks? The CO2 is still there and that warming will show up big, and you get abrupt climate change.

    I think someone like Daniel Quinn would see such suggestions as just an example of how humans like to do more things that don’t work to fix lifestyles that don’t work- rather than say “how do we fix what is wrong” we should ask “how do we get the way we want.” — Chris

  27. PaulM:

    What we need to do in this situation is already a given, and we are currently proceeding down the path that will give us the results we need. Furthermore, this direction we are taking is past the point of no return. In short, we need to cull the herd and soon enough it will be happening. I conjecture in 200 years 80-90 percent of species will become extinct, and humans will lose about 80 percent of the population, a conservative estimate. The remaining people and surviving plant and animal life will have to adapt to 130 degree land temperatures, with the oceans being slightly cooler. There is even an outside chance we go the way of the other planets and become inhospitable to life. Hopefully there will be some relics of life on this planet after a few million years, that show we even existed. Anyways, tell your grandkids to think twice about having kids, for they may suffer because of a hot environment. We always talk about the world we leave our grandkids, the time to talk to them about what is to come has arrived.

  28. Larry:

    Would devoting 10% a year to the problem be worth it? I doubt that, too, in comparison to more pressing research needs.

    If we understand GW so well, what are the pressing research needs?

    We know the earth is warming.
    Most say it is man made.
    According to this site we know how CO2 and temp increase are related.

    I guess what we don’t know is how things like ocean currents, jet streams will respond, but what is there to study until it happens?

    [Response: We know enough to essentially rule out a very small climate sensitivity, but there’s still a lot to learn about how bad things could get on the high end. Changes in the ocean, ocean chemistry and biology on land and ocean need a lot of study. There’s all that ice dynamics stuff that had to be left out of the IPCC because it couldn’t be properly modelled yet. There’s a lot to learn about regional climate change. A lot to be learned about the carbon cycle on both ocean and land. Basically, there’s a lot to be learned about just how bad things could get. Also, of course, a lot to be learned about how to emit less CO2. –raypierre]

  29. Lou Miller:

    My idea of a thriller novel, with at least the plot potential of State Of Fear, has for years been a group of rogue scientists who drill down to near the magma of a volcano on a remote Indonesian island and drop a nuclear bomb down there to break things loose and start a real volcanic reaction–leaving us with lots of sulfates in the atmosphere. Why not use Mother Nature by giving her a little nudge? And the ending would have the mandatory blond (female) scientist member of the team ride the bomb down into the intense heat of the magma like Slim Pickens in Dr. Strangelove. Any takers?

  30. Andrew:

    Einstein once said that a problem can not be solved at the same level of awareness that caused it. Geoengineering is more of the same thinking that got us to where we find ourselves today – in big trouble.

    Our world’s industrial and economic systems are out of alignment with the earth’s ecosytem. The sooner we reach that level of awareness – focusing on renewable, clean energy, closed loop recycling, and making the waste from one process the fuel for another – the sooner we will solve the problem of which AGW is a very dangerous symptom.

  31. Wayne Davidson:

    Absolutely not, no fighting pollution with pollution! There is more room for creative solutions though, worth while geoengineering: extraction of CO2 complementing trees, yes by all means… We already know what happens when we tinker with the environment, a wide range of unexpected transformations occur. Like the melting of a wide region of Polar ice causes all kinds of meteorological dynamical changes causing droughts several thousand miles away. Adding sulfur to the statosphere would do some real serious direct or indirect chemical chain reactions, already known by past volcanic events, when stratospheric Ozone concentrations dip after strong eruptions.

  32. John Reimann:

    So, first the WSJ runs article after article denying or belittling the significance of human caused global warming. Then they turn around and run an article advocating that massive amounts be spent to mitigate it by sending pollution up into the atmosphere! Anybody see a contradiction here?

  33. James:

    Let me offer a rather more practical solution: explode a few nuclear bombs every now and then. Not enough to cause a full-scale nuclear winter, just a bit of nuclear autumn.

    I say this is practical because if it’s done early, the explosions can be targeted to uninhabited places, whereas if the world keeps on dithering, we’ll likely see a larger number exploded in inhabited ones.

    [Response: Umm, I know you’re just being ironic, but if I may for the moment pretend to take you seriously, I should point out that virtually all of the soot aerosols that cause nuclear winter come from combustibles ignited by the blast, not the blast itself. In the current theories the large(ish) climate effects come about because cities have a very hign combustible density. So, sorry, but nuking uninhabited areas wouldn’t do the trick, unless you’re talking about evacuating cities and doing large scale nuclear demolition. –raypierre]

  34. Vern Johnson:

    Sounds like George Bush better not get involved “deciding” anything in this direction.What is amazing to me is that Cheney and Addington have seen to it that Bush’s Presidential powers deprive the rest of us any input, either in the inane policy of pre-emptive war, torture, warrantless wiretaps or anything else. Just imagine what might happen if a US Justice Dept were to now conjure up powers for George that would allow him to act unilaterally in the “war on global warming”. Frightening prospect of the US dumping sulfates into the atmosphere purposely, or using their nuclear arsenal to activate volcanoes. Wow! Such hair-brained ideas I have not seen for a lifetime. Surely this web-site is not going to pay serious lip-service to such utter nonsense! Get serious.

  35. Pekka J. Kostamo:

    A minor contribution to the idea bank.

    Looking at the Arctic ice event this year, it seems to me that a major part of that particular problem came with warm waters flowing through the Bering Strait into the Arctic Sea. It is a narrow (85 km) and very shallow (55 m)strait with a continuous northward flow (1 m/s) that siphons warm surface water from the Pacific. See the thermal maps at

    A dam to cut this flow sounds like an easily doable engineering project. Not too expensive, either. The modification could even be considered reversible, in principle at least.

  36. Richard LaRosa:

    In addition to reducing greenhouse emissions, we can upwell cold water and nutrients to cool the surface and increase ocean food production. This will convert CO2 to orgnic matter. The pumping can be done with power derived by a heat engine from the solar thermal energy stored in the ocean surface water.

  37. J.C.H.:

    Why is there not more attention paid to white? The oil companies possibly would not lose a dime on a large reduction in CO2 emissions. Just have the reduction in hydrocarbon emissions dedicated instead to making massive amounts of quality white sheeting. The carbon would be sequestered. The oil companies would get their cash. Ordinary people would feel involved in fixing this mess by covering large areas of the ground with white film. It seems to me there are areas of the earth that could dedicate some land to be white year round without causing devastation to the environment. In other areas, roll it all back up and store it until the next season.

  38. Chris:

    RE 33 and reply

  39. PHE:

    Geoengineering the atmosphere?
    A dangerous thing to even think about. If we get it wrong we could plunge into manmade global cooling, and what would that bring? Unstable weather patterns; reduction in crop growing season; large increase in cold-related deaths of humans; loss of Polar bears starving because they can’t get at the fish through the thicker ice; etc, etc.

  40. Pascal:


    I asked many times now, without a single answer, which is the opinion of realclimate contributors concerning the relative freshening of SH oceans.(look at Hadley SST data for example)
    I think you are agree that thermal flux in the ocean can change considerably the amplitude of global warming.
    At the limit the oceans are sufficiently cold to absorb completely the GHG warming.(mean temperature about 4/5°C)
    Is there some reality in this idea?
    For example the poleward shift of trade winds in SH?

    Can you, please, answer me?

  41. Eachran:

    Looks like we need a lot of geo-engineering to fix things, especially if the news everyday is bad.

    First a piece in The Guardian today to make you miserable and then some news from France to cheer you all up.

    ‘Uncertainty’ over climate change
    Press Association
    Friday October 26, 2007 6:43 AM

    Uncertainty about the extent of future global warming is in itself an indicator of serious climate change to come, scientists have claimed.

    In most areas of science, uncertainty weakens evidence and makes it harder to prove a hypothesis.

    But two US experts argue that climate change is different, because of the way its uncertainty is a reflection of sensitivity.

    “Feedbacks” in the climate system that can magnify global warming are so wide ranging and unpredictable that it becomes difficult to make firm forecasts.

    However, these are the very factors that are likely to contribute to high levels of warming.

    Scientists Dr Gerard Roe and Professor Marcia Baker, from the University of Washington in Seattle, have now produced a mathematical equation for climate modellers designed to take uncertainty into account. It links the probability of warming with built-in uncertainty about the physical process that affect how much warming will occur.

    Current projections point to average world temperatures to rise between 1.1C and 6.41C between 1990 and 2100. The equation shows that more extreme temperature changes – perhaps 15F (8C) – are possible, though not probable.

    “Uncertainty and sensitivity have to go hand in hand. They’re inextricable,” said Dr Roe, whose research is published today in the journal Science. “We’re used to systems in which reducing the uncertainty in the physics means reducing the uncertainty in the response by about the same proportion. But that’s not how climate change works.”

    An example of a feedback is the way a carbon dioxide-rich warmer atmosphere holds more water vapour, which is in itself a greenhouse gas. The increased water vapour then amplifies the effect on temperature caused by the original increase in carbon dioxide.

    “The kicker is that small uncertainties in the physical processes are amplified into large uncertainties in the climate response, and there is nothing we can do about that,” said Dr Roe.

    Copyright (c) Press Association Ltd. 2007, All Rights Reserved.

    And the news from France is that Mr Sarkozy yesterday announced that carbon taxes will be introduced in conjunction with a review of the tax system. If France can do it then the rest of Europe can and dare I say it the US and other states too.

    The devil is always in the detail so let’s wait and see what the French proposals are but we need carbon taxes urgently as the background for improving on current and developing new technology.

  42. Jim Cripwell:

    On another part of RC there was the following post. “This is off topic, but can anyone direct me to an explanation of the differences between the NASA temperature anomaly analysis and the Hadley center’s? I know the primary difference is at the poles, but I don’t understand the details.


    Comment by cce — 21 October 2007 @ 2:37 AM”

    I could not find any answer, but I am extremely interested in any answer, particularly if it could include the data from NCDC/NOAA. Can anyone lead me to any sort of answer?

  43. Kevin:

    These sorts of proposals to do something even more outrageous to try and counteract the last outrageous act remind me of a song from my childhood:

    There was an old lady who swallowed a fly.
    I don’t know why she swallowed that fly–
    Perhaps she’ll die.

    There was an old lady who swallowed a spider,
    That wiggled and jiggled and tickled inside her.
    She swallowed the spider to catch the fly.
    I don’t know why she swallowed that fly-
    Perhaps she’ll die.


    There was an old lady who swallowed a cow.
    I don’t know how she swallowed a cow!
    She swallowed the cow to catch the dog …
    She swallowed the dog to catch the cat …
    She swallowed the cat to catch the bird …

    There was an old lady who swallowed a horse–
    she’s dead, of course.

    Clearly I internalised this important philosophical lesson at an early age, and thus find myself instinctively back away from such well-meaning suggestions.

  44. Alastair McDonald:

    Re #33 While using nuclear explosions to solve the problem of AGW is almost certainly less political acceptable than the alternative of building thousands of nuclear power stations, it could produce a solution that would be more effective if the situation becomes urgent.

    Ray, you responded that “… virtually all of the soot aerosols that cause nuclear winter come from combustibles ignited by the blast,” and that “… the large(ish) climate effects come about because cities have a very hign combustible density.” OTOH, if a nuclear weapon was exploded on or under the ocean surface, then water vapour would be ejected into the stratosphere.

    This could be done in the central Pacific Ocean, where it would be far from human habitation. It might require the evacuation of some islanders, but since rising sea levels will mean their evacuation anyway, this would not be a net loss. Another advantage is that the substance being injected is natural being water (i.e. no acid rain), and its persistence in the stratosphere is known to be short.

    Moreover, we do have experience of nuclear explosions over water. The Operation Crossroads tests by the US Navy in 1946 produced a frozen UK in the Spring of 1947. Weapon testing by the USSR in the Arctic during October 1961 resulted in heavy snowfalls in the UK in the winter of 1962/3 but it is difficult to draw conclusions since natural variability, the solar cycle and El & La Nini can also affect the global and local temperatures.

    Let’s hope that one of your colleagues at the Harvard meeting has given it some consideration.

  45. simon Edmonds:

    A cheap and sustainable method to produce electricity and water without CO2 emissions is the CETO wave energy technology. Its right here right now, only political and business lobbying stands in the way of a solution to this crisis. Our civilisation is in a race against time, all of our talk is going on while the clock is ticking and the threshold is approcaching quickly. GO FIGURE.

  46. Martin Vermeer:

    #23 Dan W: Can you say “taller smokestacks”?

    The other inmates agree ;-)

  47. Ray Ladbury:

    re 40: “only political and business lobbying stands in the way of a solution to this crisis.”

    Right! While promising, this is still unproven technology–in the sense of being able to generate and deliver power economically. There is no one solution.

  48. Tom Adams:

    One interesting thing about this is that (as far as I know) it could be done by a single nation or any coalition that has the resources. Contrast with the effort to reduce CO2 which requires agreements among all major emitting nations.

    So, a group of nations that are being most injured by global warming could do it.

    Of course, feasibility would depend on the cost and the sort of pressures that might come from the rest of the international community.

  49. PaulM:

    Number 45 has touched upon the only viable solution and number thirty reinforces this idea, for you cannot solve a problem with the same level of awareness indeed, and 45 and wave energy theory is “getting warmer” to the solution, pardon the pun. Remember, matter has the quality of acting either as a particle of wave, and the whole particle theory while intelligently presented, tended to push out the wave theory, and we have been going down that path ever since. Not to push quantum mechanics on anyone, but therein holds the solution, not only giving the planet energy it needs, but also cleaning up the planet also. We humans tend to take the path when the light bulb goes off, but in the case of atoms as matter it closed the door on waves from the get-go, and we went down that road and here we are. Needless to say, this round of humanity didn’t make the grade, and unless one doesn’t mind an oven environment we actually need to scrap ourselves and start from scratch. Maybe the next batch of intelligent creatures will fare better. The earth is like a remote village that never really got the chance to see what else is out there, at least not yet.

  50. Surly:

    We need geoengineering of people’s minds. Obviously, there are forces at work trying to prevent action on reducing CO2 production. If they can stall long enough, they will succeed and by default, we will be forced into grandiose geoengineering strategies to save ourselves. The science fiction lover in me appreciates such scenarios and fixes and even at times thinks such fixes will lead us into technological advances we wouldn’t have had without such a crisis, but the ordinary human in me fears our hubris.

    “Swallowing the Horse” — sounds like a great title for a science article on geoengineering and its potential foibles.

    [Response: Gee, I wish I had thought of that title before I wrote that post. Can I keep it in mind for the future? In a similar vein, you could think of the old Ray Ventura song, “Tout va tres bien, Madame la Marquise.”]