Geo-engineering in vogue…
There was an interesting article in the NY Times this week on possible geo-engineering solutions to the global warming problem. The story revolves around a paper that Paul Crutzen (Nobel Prize winner for chemistry related to the CFC/ozone depletion link) has written about deliberately adding sulphate aerosols in the stratosphere to increase the albedo and cool the planet - analogous to the natural effects of volcanoes. The paper is being published in Climatic Change, but unusually, with a suite of commentary articles by other scientists. This is because geo-engineering solutions do not have a good pedigree and, regardless of their merit or true potential, are often seized upon by people who for various reasons do not want to reduce greenhouse gas emissions. However, these ideas keep popping up naturally since significant emission cuts continue to be seen as difficult to acheive, and so should be considered fairly. After all, if there was a cheaper way to deal with the CO2 problem, or even a way to buy time, shouldn't we take it?
First a little history [Update: See Spencer Weart's essay on the history of climate modification ideas]. Geo-engineering ideas first reached the public in the 60s when there was still a lot of enthusiasm for technical fixes of the world's problems. One example was suggested by the Soviets who wanted to melt the Arctic (either using soot or nuclear devices) in order to warm up their frozen North. More recently, there was a proposal to dam the Straits of Gibralter in order to prevent more saline Mediterrean Sea water (because of the Aswan Dam) from affecting the North Atlantic conveyor circulation (no, it didn't make sense to us either). With such a pedigree, geo-engineering is generally seen as fringe entertainment at best, although some of the new ideas concerning atmospheric carbon dioxide sequestration are being looked into seriously.
Edward Teller is the scientist most associated publicly with the idea of creating a stratospheric shield to prevent excessive global warming, though he built on an idea from Freeman Dyson (who has subsequently become a bit of global warming contrarian)*. However, as Teller's collaborator Stanislaw Ulam once said after discussing some new ideas with him: "Edward is full of enthusiasm about these possibilities; this is perhaps an indication they will not work". And given Teller's estrangement from the scientific community in his later years, it was not likely that the concept would be taken very seriously, and indeed it hasn't been.
*Which in turn built on a idea from Budyko…(see comment below).
But now Paul Crutzen has stepped into the fray. He has a much more solid reputation amongst climate scientists than Teller, and thus his ideas will be taken more seriously. I haven't seen the new paper yet (it's out in August) but there are a number of questions that need to be addressed before any geo-engineering proposal combatting global warming should be thought of as anything more than an interesting idea. First, the idea has to actually work, second, the side effects need to be minimal, and third, it has to be able to keep up with an increasing forcing from ever higher greenhouse gas levels, and fourth, it has to be cheaper than the simply reducing emissions at source. These are formidable hurdles.
Would it work? In most of the cases under discussion the target is the global mean temperature, and so something that balances the global radiative forcing of greenhouse gas increases is likely to 'work'. However, having no global mean forcing is not the same as having no climate change. A world with higher GHGs and more stratospheric aerosols is not the same as a world with neither.
Thus there will be side effects. For the stratospheric sulphate idea, these fall into two classes - changes to the physical climate as a function of the changes in heating profiles in solar and longwave radiation, and chemical and ecological effects from the addition of so much sulphur to the system. Physically, one could expect a slight decrease in surface evaporation (a 'dimming' effect) and related changes to precipitation, a warming of the tropopause and lower stratosphere (and changes in static stability), increased Eurasian 'winter warming' effects (related to shifts in the wind patterns as are seen in the aftermath ofvolcanoes). Chemically, there will be an increase in ozone depletion (due to increases in heterogenous surface chemistry in the stratosphere), increases in acid rain, possibly an increase in high cirrus cloud cover due to indirect effects of the sulphates on cloud lifetime. Light characteristics (the ratio of diffuse to direct sunlight) will change, and the biosphere may react to that. Dealing with the legal liability for these predictable consequences would promise to be a lively area of class action litigation…. On the positive side, sunsets will probably be more colorful.
Could it keep up? GHGs (particularly CO2) are accumulating in the atmosphere and so even with constant present-day emissions, the problem will continue to get worse. Any sulphates put in the stratosphere will only last a couple of years or so and need to be constantly updated to maintain concentrations. Therefore the need for the stratospheric sulphates will continue to increase much faster than any growth of CO2 emissions. This ever-increasing demand, coupled with the impossibility of stopping once this path is embarked upon is possibly the biggest concern.
How expensive would it be? I will leave the detailed costing to others, but stemming from the last point, the cost will continue to rise indefinitely into the future unless this proposal is coupled with an concommittant effort to reduce CO2 emissions (and concentrations) such that the need for the sulphates will diminish in time.
Crutzen's paper may well address these issues comprehensively (and I look forward to seeing it) but, in my opinion, the proposals are unlikely to gain much traction. Maybe an analogy is useful to see why. Think of the climate as a small boat on a rather choppy ocean. Under normal circumstances the boat will rock to and fro, and there is a finite risk that the boat could be overturned by a rogue wave. But now one of the passengers has decided to stand up and is deliberately rocking the boat ever more violently. Someone suggests that this is likely to increase the chances of the boat capsizing. Another passenger then proposes that with his knowledge of chaotic dynamics he can counterbalance the first passenger and indeed, counter the natural rocking caused by the waves. But to do so he needs a huge array of sensors and enormous computational reasources to be ready to react efficiently but still wouldn't be able to guarantee absolute stability, and indeed, since the system is untested it might make things worse.
So is the answer to a known and increasing human influence on climate an ever more elaborate system to control the climate? Or should the person rocking the boat just sit down?
28 June 2006 at 6:45 PM
The first time a tomato crop gets a frost in an area it never happened before the ‘geo-engineers’ will get sued.
28 June 2006 at 7:27 PM
And even if it was possible to cool the planet, this type of geo-engineering won’t stop our seas from becoming acidic and much of marine life being wiped out. It would still leave us with a much diminished planet.
28 June 2006 at 7:52 PM
This reminded me of a song. It begins
“I know an old lady who swallowed a fly…”
28 June 2006 at 8:17 PM
I read the article. It was interesting. However, if we are going to consider radical solutions (which we should), we should also consider standing down the greenhouse gas economy, except for essential services, for some periods of time each year. We could survive not driving our cars or running our factories and businesses for a few weeks each year if we plan it carefully. Like other forms of conservation planned annual stand downs of our economy could be a significant contributor to a mix of approaches and technologies that reduce greenhouse gas emissions.
28 June 2006 at 8:34 PM
Most credible scientists seem to suggest that reducing emissions is the only practical and prudent approach to mitigating climate change. However, geo-engineering may be worth exploring as a possible reaction to severe runaway climate impacts.
28 June 2006 at 8:38 PM
I don’t know if most skeptics are “good faith” skeptics, but if one assumes so, one can be more understanding of the techno-fix appeal. For one, if one already adopts the skeptic position that climate isn’t changing much anyway, then the techno-fix wouldn’t be as difficult or costly in their estimation (e.g., less sulfur would need to be pumped into the atmosphere). Of course, to argue that way, one would have to eat the argument that we’re insignificant and can’t influence climate (e.g., one might have to admit that aerosols were highly responsible for cooling from 1940-1970).
I have a different reason for liking the techno-fix, and Gavin alluded to it: “if there was a cheaper way to deal with the CO2 problem, or even a way to buy time, shouldn’t we take it?” Say we need 20 years to get our sh*t together and reduce emissions, but we only have 10 before the tipping point (where ice melting becomes irreversible, for example), maybe it’s worthwhile to pump out massive amounts of harmful junk, paint roofs white, whatever is possible, to avoid that tipping point. I’m thinking (hoping in vain?) that the techno-fix approach is also a bit of a practical response to geographic non-conformity in reducing emissions. That is, if some countries simply can’t/won’t alter their emissions trajectories on the needed timeline, perhaps by forcing them to emit sulfur is a way of putting the costs on them. Alternatively, for countries too small to absorb the costs (in terms of acid rain and other pollution in their own skies) strategic siting of sulfur emissions by other countries can make them bear the costs of their refusal to reduce CO2 emissions.
I dunno much about legal and other ways that countries interact, but it seems like there must be a way to pressure them (http://news.bbc.co.uk/2/hi/science/nature/5121334.stm). The link is for a story about German decisions weakening the attempts of other EU countries to reduce emissions. It would be nice if pressure points could be found that act in the opposite direction.
28 June 2006 at 8:57 PM
http://www.google.com/search?q=ocean+acidification+shell+%22food+chain%22&start=0
Seattle PI story among the first hits:
“You don’t have to believe in climate change to believe that this is happening,” said Joanie Kleypas, an oceanographer with the University Corporation for Atmospheric Research, a non-profit organization based in Boulder, Colo. “It’s pretty much simple thermodynamics.”
…
“Acidification is more frightening than a lot of the climate change issues … “
28 June 2006 at 9:54 PM
As someone said - if we are going to look at this we should at least look at the real cost of a combination of efficiency measures and renewable. I suspect the lower cost from efficiency combined with the higher cost of renewables would yield a net cost of zero to get off of fossil fuels.
28 June 2006 at 10:23 PM
I have to admit, the fact that this is being discussed makes me sick. The stratospheric sulphate will cause acid rain. If this acid rain is in any significant quantity it will send insurance bills soaring. Just look at the EPA’s acid rain projections:
“A 2005 study estimates that in 2010, the Acid Rain Program’s annual benefits will be approximately $122 billion (2000$),”
http://www.epa.gov/airmarkets/cmprpt/arp04/index.html
“When fully implemented by the year 2010, the public health benefits of the Acid Rain Program are estimated to be valued at $50 billion annually, due to decreased mortality, hospital admissions, and emergency room visits.”
http://www.epa.gov/acidrain/effects/health.html
Those are some big numbers.
There are a lot of physicists that are calling for an energy Manhattan project yet their voices fall on death ears. And it’s not just republicans that don’t seem to hear them. I mean you never see articles in the newspapers pushing for an energy Manhattan project. Those that do hear the physicists seem so say “what can we do?” and yet there seems to be so many possibilities to me. I even made a website listing them:
http://www.logicalscience.com/technology/
An energy Manhattan project would require $10 billion a year. $10 billion a year is nothing in relation to the $3 trillion energy industry or even the acid rain induced medical bills. I’m currently writing an article about this on my website to convince all the right wingers/neocons I know. Liberals are easy to convince when it comes to the environment. Republicans require a different approach. Ironically, after doing some research for this article, global warming went from primary concern to a mere “secondary” concern simply because there are so many other threats we have to deal with. Threats that seem to go ignored.
28 June 2006 at 10:40 PM
Re #3: Great (or not so great!) minds think a like. Just last night in another forum commenting on this article, I called it the “swallow a spider to catch the fly” approach. Not that I think these things aren’t worth thinking about…especially as backup plasn if we get desperate. But, I do find it ironic when these approaches are often put forward by the same folks who say that the science is fraught with uncertainties. To me, this is the sort of approach that requires far more certainty in our understanding of the full climate system than to simply try to reduce our perturbation on the system (which I guess is basically the point of Gavin’s rocking-the-boat analogy).
28 June 2006 at 10:41 PM
Nuclear energy needs and deserves climate scientists’ endorsement. Efficiency and renewables are fossil fuel tax beneficiaries’ code words. They mean whatever doesn’t work; whatever keeps the oil and gas tax money coming in.
Public money has those strings attached. Taking it and not endorsing nuclear energy is not at all a morally neutral act; it’s going along to get along.
I won’t be upset if this comment does not appear.
— G. R. L. Cowan, former hydrogen fan
28 June 2006 at 11:11 PM
Re #1: If a geo-technical fix has widespread unanticipated negative consequences (ala John Miller’s famous quip about fertilizing the subtropical Pacific with iron, “Give me a freighter full of iron filings and I’ll give you another ice age” - or words to that effect - we’ll have a real Tragedy of the Commons.
28 June 2006 at 11:19 PM
There are these wild swings, in posting themes. Is this a system just a trifle chaotic, perhaps ??
Just recently, we have a plea and post to look more carefully at paleoclimate, as perhaps as one of several possibilities–and reasonably measured ideas– for better understanding of the underlying present geophysics at work in global change melting , and now this really far out global engineering idea, from a Nobel prize winner, no less.
Ok, maybe chaos is bit of a natural phemonenon. But…??
from an interested, and duly amazed, non climate scientist type.
28 June 2006 at 11:22 PM
Oops - I meant geo-engineering fix.
As I recall,it was Willard Bascom, an engineer-turned-oceanographer who coined the slogan, ” The solution to pollution is dilution” back in the early ’70s to justify using the ocean as a dumping ground. While that sometimes works on a small scale, it clearly has backfired on a global scale. That is one of the problems with engineers - they are trained to solve practical problems but often fail to see the big picture, or fail to appreciate the esthetic components of possible solutions.
29 June 2006 at 12:16 AM
I remember hearing that the US temperature was raised noticeably after 9-11 when planes were grounded, giving credence to the theory that air plane jets act as a noticeable shadow reflecting UV away from earth. I am afraid of “our” ability to control gases in such a large proportion to make a difference, and by the time we do, if might be too late to belatedly find out another unintended consequence. I am thinking of so many 19th century colonial screwups such as goarse in NZ, brought in for farm fencing, which took over the country rapidly… So maybe there is another way to do something but more nimbly in case it backfires.
Perhaps a quick fix would be to launch into space some large object to act as a partial light shield (modular construction could be enlarged in space, honey comb form allowing some light). It need not cover the earth, just the poles. — The closer we get it to the sun, the smaller the object need be. Thrusters would make sure it would attain an orbit around the sun mimicking the Earth’s. This object would be positioned to be a partial shadow of the North pole in its summer, and the south pole in its summer. Effects would be able to be tracked immediately and if they do other unintended consequences, it could be removed immediately.
On a related note, I also remember seeing that one of the methods they are looking into for meteor deflection, is to attract it to a space craft and nudge it using thrusters. Perhaps we can use a meteor as a light shield — force it into a similar orbit shielding parts of the north pole, or south pole.
Does any of this make sense?
[Response: No, it doesn’t. A meteor, or even several thousand meteors, would not have enough cross section area to block the amount of sunlight you’d need to block. There were proposals to build a shield either with mylar mirrors or with an orbiting ring of copper needles. The mirror is hard to keep in place and maintain, and the problem with the needles is that if you’ve overdone it and don’t like the climate you like, it’s hard to gather up the junk and undo the damage. –raypierre]
29 June 2006 at 12:27 AM
The Romans had a phrase for such things that they borrowed from the Greeks: Deus ex machina or ἀπὸ μηχανῆς θεός ápo mēchanēs theós, (OK, I copied the last one) http://en.wikipedia.org/wiki/Deus_ex_machina for those of you who slept through classics.
29 June 2006 at 12:44 AM
What if we did inject sulphate aerosols into the stratosphere, and then a large volcanic eruption occurred? It would be too late to change our minds. Would we then experience a “year without a summer”, as has happened after other large eruptions? Any safe geo-engineering solution must provide the capability for almost immediate adjustments, so we can compensate for natural fluctuations that are out of our control. Civilization may be much less robust to sudden severe climate changes then it was in the 18th century.
29 June 2006 at 1:23 AM
When I was a kid in 1950’s Los Angeles, watching folks drop like flies from smog inversions, a proposed solution to air pollution was to blow up a mountain at the periphery of the Valley - using an atomic device! - so the smog would be blown into the desert through the gap in the mountains.
Hmmm. So the solution to Global Warming is… the world should generate its power using high-sulphur coal?
Frankly, I like the A-bomb idea better.
JF
29 June 2006 at 1:25 AM
There is a lot of cold water at the bottom of the ocean. It can be pumped to the surface and discharged through perforated fabric hoses so that it will mix with the surface water and lower the surface temperature. The enormous pump power required to pump the enormous quantity of cold water can be supplied by using the OTEC (ocean thermal energy conversion) technology developed in the 70’s and later.
29 June 2006 at 1:32 AM
Eugene, look at the geometry and sizes to get an idea how big a sunshade is needed and what shape the shadows are since the Sun is so much bigger than Earth
http://domeofthesky.com/images/annularB.gif
http://domeofthesky.com/images/moonUmbra2.jpg
“… the sun is about 400 times farther from the earth than the moon, and its diameter is approximately 109 times greater than that of earth.”
http://www.perseus.tufts.edu/GreekScience/Students/Kristen/Aristarchus.html
29 June 2006 at 1:52 AM
I can’t wait for the movie where the hero and heroine struggle to set off matching volcanoes on either side of the world with split second timing. Global warming has reach critical…a suicidal CEO is intent on thwarting their plans because his son did not get into Harvard.
29 June 2006 at 1:56 AM
There is only one number that fortells the fate for humans, and that number is how many parts per million co2 is in the atmosphere. Levels on Earth will soon force the North Atlantic current to shut down. Humans will lose the northern and southern icecaps, as well as the mountain glaciers.Superstorms will bankrupt the insurance industry as well as the reinsurance industry. Carbon taxes will bring co2 to above $170 per ton,US, and you will need a permit to exercise outside, never mind driving a vehicle. Oh, by the way, the sulpher dimming idea is just plain dumb.Also, by the way, many earthlike planets have suffered the same fate. Earth is in no way special, having thus shown so far the total paucity of vision and intelligence from the “dominant” species.Good luck, humans.PS,I thought that most people who read this website had already passed global warming 101.P.PS. if it seems that I am both arrogant and highly educated it is because I am.
29 June 2006 at 1:56 AM
This is wat i believe………..A general prediction of global warming does not just suggest that there will be an average higher world temperature. It also proposes that there will be greater variations in temperature with more extremes of local heat and cold, higher or lower precipitation, more storms and more droughts.
29 June 2006 at 2:34 AM
I do not think that cooling the planet artifically is even close to a good idea. How are we to know the consequences of our cooling actions? Who’s to say that the cloud bursting in China is not encouraging wild fires in the states? It is much better to fix the problem rather try to engineer a band aid solution.
29 June 2006 at 2:54 AM
The only real benefit to this proposal I can see is the prospect it offers of separating researchers who really don’t believe Global Warming is taking place (if there are any) from those who are merely taking the money and running their mouths according to the wishes of their paymasters.
The former will oppose this desperately, because they’ll see it as giving chemotherapy to a patient misdiagnosed with cancer; the latter will rush to embrace it because that’s what their bosses will want. Their bosses will want it, of course, because they think it may buy them a few more years to do with the world as they will, even though they will realize the scheme is ridiculous.
29 June 2006 at 5:20 AM
Re: 13
Certainly the idea of a solar shield at the Lagrange point between the Earth and Sun has been mooted. It’s certainly better than sulphate aerosols, with the minor problem that an accident or metorite strike could destroy the whole thing in a single go..
As others have pointed out, it would still not prevent ocean acidification, and the overall heat distribution may well change.
Re:17
An interesting idea, but I’d like to see the underlying calculations. What proportion of the oceans would have to be overturned each year (the natural rate being circa 0.1%).
If we are warming water by 15K, that means that every cubic kilometer of water overturned will absorb 4.2*15*10^15 J. (~6×10^16 J)
If we take total forcing as 4W/m2 x 5.1×10^14 = 2×10^15W
(for a year, this would be 3×10^7 x 2×10^15 = 6×10^22 J)
This implies 10^6 cubic kilometers. The volume of the cold, deep oceans is around 10^9 cubic kilometers. So we could in theory do this for 1000 years before the entire ocean was warmed to 15C. This would, I believe, raise sea levels by up to 10 meters. More to the point, within a relatively short time of starting this pumping scheme, natural ocean circulation would be disrupted.
Re: 9
Yes, replacing coal burning with nuclear would appear to be one of the easiest, pain-free ways to reduce CO2 emissions. But that’s a bit off-topic.
29 June 2006 at 5:37 AM
PLease don’t forget side effects :
as it was previously said here, it won’t prevent acidification of oceans but such molecules like sulphates are known to provoke acidic rains, and even atmospheric pollution for some sensitive organisms like lichens.
And the other question, like it was previously discussed for stabilisation of the ozone layer, is what quantities of enginered gazes would have been released to neutralise warming effects of carbone dioxide and methane ? Is the range compatible with the scale developped countries could be ready to give to such a strategy.
Really sceptic I am considering all these considerations in balance…
29 June 2006 at 5:42 AM
When will Humanity be able to live in harmony with its environnement ?
Trying to correct a problem by addind another layer of engineering is noting less that adding complexity and unpredictability to the system, running to a global disaster when no solution will remain to balance a higly modified complex oceano-atmosperic system…
29 June 2006 at 6:35 AM
There’s no reason to reduce CO2 in the first place.
CO2……. is good.
You guys not worked that out yet?
Seems you are a bit slow.
29 June 2006 at 7:16 AM
How about these radical geo-engineering concepts: conservation and birth control?
29 June 2006 at 7:34 AM
The opening sentence of this thread states,” … the global warming problem.” Can anyone here direct me to documents in which are described the processes and procedures that were used to arrive at an exact and accurate specification of ” … the global warming problem.” Exact and accurate specifications in the sense of the known/proven consequences if “the problem” is neglected and the rank of “the problem” in a list of pressing issues facing humankind world wide.
This blog in my opinion continues to accelerate its movement away from its originally stated purpose. As support for this statement I point to the increasing number of threads based on issues that appear in the daily newspapers and “news releases”.
[Response: The main reason for this blog was to provide context for the public discussion of climate change. And that’s what we do. For a detailed specification of the problem, read the IPCC TAR and references therein. - gavin]
29 June 2006 at 8:11 AM
I wonder why it is that these types of solutions seem more ‘possible’ than emissions reduction strategies? Is it the seductiveness of the grand project? Or perhaps, some other attribute of centralized solutions? Just what are the barriers that reductions face that these proposals avoid? Cheaper? For who, by what calculation?
Even if we didn’t face climate change, even if it were for reasons of health or aesthetics, wouldn’t pollution reduction be worthwhile anyway? Unless we can redefine what is ‘possible’, I find little reason for optimism.
29 June 2006 at 8:56 AM
The idea of spreading particles in the stratosphere to retard global warming did not originate with Dyson but, so far as I know, with the Russian climatologist Mikhail I. Budyko ca. 1974. This was in keeping with Soviet dreams of “conquering” nature, but even Soviet scientists were dubious about such schemes. See www.aip.org/history/climate/RainMake.htm (comments welcome).
[Response: Thanks! Serves me right for reading Teller’s papers a little too uncritically. - gavin]
29 June 2006 at 9:38 AM
Speaking of geoengineering, can anyone comment on this book: “Plows, Plagues, and Petroleum: How humans took control of climate” by William Ruddiman? I’m looking for a copy but the publisher’s blurb on the Powells Bookstore website gave me pause because it seemed to suggest that human-caused climate forcings were all that stood between us and another ice age (which sounds too much like the Western Fuels Assn. for my taste).
29 June 2006 at 10:29 AM
Re: #11 (arguing that we must go nuclear to reduce greenhouse gases):
Here is a letter I just sent to an author proposing the same:
———————–
Dear Mr. Sweet,
I just finished your book, Kicking the Carbon Habit: Global Warming and the Case for Renewable and Nuclear Energy, and I wanted to write to commend you for it.
However, I must add (as an undergraduate nuclear engineer who later taught nuclear plant operations in the Navy and who took a a master’s in engineering management while working at the Hanford nuclear reservation, before becoming an attorney) that the discussion of nuclear power needs significant expansion to address a key issue, one that you clearly recognize as critical when discussing other forms of energy. We can call this the EROEI (energy return on energy invested).
There is a growing realization that nuclear plants require so much embedded energy that they are net energy sinks for a non-trivial period, and that nearly all of this energy causes the release of CO2.
That is, the enormous amounts of energy that go into making the plants (particularly in concrete but also in various steels) and the fuel rods (mining, milling, enriching, fabricating) is not at all insubstantial.
Thus, it is incorrect to ignore this or to say that nuclear plants are essentially zero carbon plants. Sure, they don’t emit carbon (or anything else) while burning fuel, but that’s like saying that hydrogen is a zero carbon fuel by ignoring all the carbon released in making hydrogen.
Naval nuclear plants, for example, use such high-enrichment fuel (to avoid refueling requirements) that they _never_ produce net energy. And while civilian light water reactors do not require that kind of enrichment, new nuclear plants still start out with a huge carbon and energy debt to work off, which means it is years before they produce more energy than they consumed along the way (I have heard estimates exceeding 15 years when all the construction and fuel cycle energy use is accounted for).
Given that a plant ordered tomorrow would probably not carry base load for ten years, and would probably not reach an energy profit for at least another decade, it’s very unclear whether the commitment of $100 billion for nuclear plants is a very wise investment for the United States. On a CO2 reduction per dollar basis, I suggest that the same money would be far more effectively spent on national and local rail projects (to elminate truck transport and to slash airline travel), combined heat and power plants (such as Tom Casten proposes, which you seemed to dismiss far too lightly), conservation, and small, distributed generation projects.
Again, I want to commend you for the book, especially for the sections discussing the climate modelers, which was fascinating. And I do hope you will revise and expand the third section so that it offers lay readers a more rigorous look at the energy alternatives and the net energy return they offer.
29 June 2006 at 10:37 AM
Ahhh, the surgeon heals by cutting, the medical doctor by dispensing drugs, the chemist proposes more chemical reactions.
Maybe I’m just a simple engineer, but I would agree with comment #8 whole heartedly (no offense #8). Many issues are much too complex to be looked at from one point of view. When it comes to energy use and global warming, I believe the bigger the system you look at–both thermodynamically and economically–the more efficiency and renewables become the best possible solution. When you include energy subsidies on the supply side, include health care costs due to pollution, DoD costs to maintain supplies, costs due to global warming, etc., energy efficiency is cheap and easy. We need much better designs of our systems–the technology is already there.
A good intro to this way of thinking can be found in a Harvard Business Review paper by the folks at the Rocky Mountain Institute:
http://www.rmi.org/images/other/Businesses/NC99-08_HbrRMINatCap.pdf
29 June 2006 at 11:24 AM
JMG, type “Ruddiman” into the Search box at top of home page; Dr. Ruddiman has participated here in discussion of his work.
29 June 2006 at 11:30 AM
Re: 15
The study of temperatures after 9/11 showed that the difference between the daytime high and nighttime low temperature increased. Daily temperature variations are too great for the researchers to have determined if temperatures increased in an absolute sens, or not. If we were to block sunlight and leave the CO2 in the atmosphere, we would compress the day-night temperature variations, and the compression would increase over time. I have no idea of the long-term consequences of that. I don’t believe anyone else does either.
29 June 2006 at 11:33 AM
The idea that nuclear power is the answer to global climate change keeps popping up. Here are a few different views:
Nuclear Power: economics and climate-protection potential
http://www.rmi.org/images/other/Energy/E05-14_NukePwrEcon.pdf
Insurmountable Risks: The Dangers of Using Nuclear Power to Combat Global Climate Change
http://www.ieer.org/reports/insurmountablerisks/
A soon-to-be-published book by Helen Caldicott:
Nuclear Power is Not the Answer
http://www.helencaldicott.com/
By the way, the numbering of comments seems to sometimes change. It would be useful if someone could find a “technical fix” for this problem.
29 June 2006 at 1:22 PM
The [Update: See Spencer Weart’s essay on the history of climate modification ideas]. didn’t work for me. It just brought-up the same RealClimate article again.
[Response: Fixed. sorry!- gavin]
I seem to remember a number of suggested engineered solutions back in the early 90s or late 80s in “Newsweek” magazine (yes, quite a long time ago). I imagine they are mostly the same ones being discussed here.
I would worry in general about the cost, efficacy, and potential side effects.
Any potential particulates that could be introduced that would reflect sunlight but would not produce acid rain or other severe side effects?
Re#6- “if one already adopts the skeptic position that climate isn’t changing much anyway, then the techno-fix wouldn’t be as difficult or costly in their estimation”
I think a more appropriate skeptic position is that the climate isn’t changing much anyway due to anthropogenic GHG emissions.
Most skeptics (and even some believers of significant AGW) oppose expensive measures like Kyoto, and they would likely similarly oppose these “technical fixes” as being too costly with too little benefit and too many potential side effects.
29 June 2006 at 1:54 PM
We have ‘geoengineered’ the planet into its current state. More of the same in a different direction will only make things much worse. We (humans in general, but industrialized humans in particular) lack the wisdom to realize this. If we do ‘buy some time’ with one of the methods mentioned, we will surely use it to pump more GHGs into the atmosphere and expand our populations and wealth, not find real solutions. Do you think the US government is suddenly going to acknowledge that climate change is real, dangerous, and human-caused, and then take drastic steps to reduce CO2 emissions?
I would suggest that geoengineering projects may initially be proposed and started by well-meaning people…and it would rapidly go to heck from there. Who better to run global-scale geoengineering projects than big multinationals? Once these companies start running the projects, concern for poorer, militarily weaker nations will become secondary, as it is now. If Africans sue the US, is the US going to pay, or change behavior? In addition, once a major industry is underway, vested interests will automatically arise to sustain that industry, even if it is causing more harm than good. The American auto industry is a prime example.
Nuclear power is also not a solution. In addition to the problems mentioned in JMG’s post #35, there is also the risk of contamination. The world is getting less stable, and climate change and increased oil prices (and reduced supply) are only going to make this worse. Do we really want to build nuclear plants in a world that is becoming less politically, economically, and socially stable? Why not spend the $100B on conservation, on car-less cities, and so on?
There is a solution, but it is not popular, because it means significantly changing “the economy,” and this has been conflated with destroying the economy. Or, as one of your most senior leaders laughably said, “The American Way of Life is not negotiable.” (He must have been warning God or Mother Nature.) Living in harmony with our environment does NOT necessarily mean a decrease in our standard of living, and it could offer a better way of life. Ultimately, it will be the only solution.
29 June 2006 at 1:58 PM
BTW, the link to “Spencer Weart’s essay on the history of climate modification ideas” just brings me back to the RC home page. I tried it in Opera and Firefox.
[Response: Fixed. sorry! - gavin]
29 June 2006 at 2:10 PM
Five years ago, of 100 units of electricity generated using slightly enriched uranium, over 98 units were net of the enrichment process.
The recent licensing of a gas-centrifuge plant in the USA is part of a continuing process in which that fraction moves into the high 990s per thousand. For heavy-water-cooled and some gas-cooled reactors it has, of course, always been 1.000.
The hand-waving reference to “not at all insubstantial” energies invested in nuclear plant concrete is an appeal to innumeracy that I trust won’t get far here. Concrete requires high-temperature calcination of clinker, so that a tonne of it represents a 1.4-GJ energy investment, and this means a 1-gigawatt nuclear electric station that feeds 800 MW to a resistance-heated clinker kiln for a year would power the production of 18 million tonnes of concrete. So it can pay for its own concrete’s production in less than a month.
29 June 2006 at 3:24 PM
A few quick questions.
#1) For the solar shield to work, how big would it have to be? Roughly.
#2) At what point do scientists project the “tipping point” point will occur? In other words, at which year/CO2 ppm will a runaway greenhouse effect comes into play?
29 June 2006 at 4:28 PM
Something that wasn’t taken into account in the article or in the responses is that the climate is not static - it readilly changes with or without our help. The next ice age will be just as destructive as the worst case global warming predictions, is it okay that billions of people die because it’s ‘natural’ or should we do something about it? Geo-engineering will be required at some point (we’re near the end of the current interglacial period compared to the length of the previous ones) - should we investigate it now and find comprehensive solutions to climate change no matter the cause, or devote all our resources to a one-off solution to the unique problem we currently face?
The least expensive and most useful solution is probably to grab the low laying fruit in conservation and alternative energy, and make up for any shortcomings with geo-engineering. Then when mother nature throws us a curveball in the future, a field of hardened, experienced geo-engineers will be ready to save billions of lives.
29 June 2006 at 4:32 PM
re: #43– Thanks for suggesting that the energy cost of certain pieces of the nuclear process are low. I (and perhaps others here) would welcome pointers to any peer-reviewed reports you are aware of that assess the energy cost of the entire nuclear life-cycle (from mining through waste storage and monitoring) so that the overall EROEI for the entire nuclear energy life cycle can be known (the kind of thing being done for ethanol).
I think we very much need that kind of information if we are to make good choices. Certainly we would have to be able to show that kind of data to be able to get enough people to support the kind of “Coal/Nuclear Covenant” proposed by R. T. Pierrehumbert that we need [6 Chi J Intl Law ___, Winter 2006].
29 June 2006 at 4:36 PM
P.S. Sorry–forgot to add that the CO2 driven off in concrete production is a concern all on its own, isn’t it?
29 June 2006 at 4:55 PM
It’s worth noting that the IPCC WGIII 2001 report addresses geoengineering briefly in Section 4.7:
http://www.grida.no/climate/ipcc_tar/wg3/176.htm
On a separate thread here, and on http://groups.google.com/group/globalchange , I recently argued as follows
While I don’t find the following decisive, it is fair to point out that there is some evidence to the contrary. An anonymous correspondent on the globalchange list pointed out that the referenced section of the WGIII report addresses this point in an optimistic way.
My intuition is that models with more degrees of freedom may not yield such pleasant results. Has this been further investigated?
I’d also suggest that any geoengineering system which does not “fail safe”, i.e., quickly decay to natural conditions without explicit human maintenance, is far too dangerous to contemplate. We can’t risk iatrogenic disease in Gaia.
mt
29 June 2006 at 5:15 PM
Many of us have been saying for years that there is already in place some form of geoengineering, for whatever purpose, but the assertion is scoffed at.
Take a look at a particularly blatant current example of atmospheric manipulation on the NRL Monterey Weather Satellite site: www.nrlmry.navy.mil/sat_products.html
Here’s how to navigate the site:
Click on West Coast & EPAC (top left box)
Scroll down to Los Angeles-San Diego VIS thumbnail (right-hand side)
Click on that, then go up to bar on top to Previous, click on that to access Index of archives.
Scroll down to 20060624 sequence of June 24, 2006 (left column currently)
Click on 20060624.1900 for most blatant image (click to enlarge)
Look at 1600, 1630, 1700, 1730, 1800 to see the evolution of a completely unnatural pattern in the atmosphere.
This is only one recent example of many weather satellite anomalies that cannot be explained as contrails left by airliners. Something is going on here that needs to be taken into account.
[Response: The image in question shows a gravity wave that is close enough to the cloud layer to affect the relative humidity as it passes through (becasue of the vertical motions associated with the wave). Gravity waves are caused by winds intersecting with mountain ranges (lee waves etc.), moist convective activity, shear in the atmosphere etc. They resemble surface waves on the ocean, but exist in the atmosphere between layers of slightly different density. You only see them when they get accentuated by clouds in air that is close to 100% saturation. No mystery there…. but it is a good image. - gavin]
29 June 2006 at 5:33 PM
I will bet one thing about the idea of spreading white films on rocky deserts: the carbon offsetting industry will soon be trying to buy up the most convenient sites as ‘low-hanging fruit’.
I wonder if there is a particular need for local geo-engineering, in particular to protect peat bogs from carbon dioxide attack, see here, by introducing certain plants, or otherwise altering their ph or salinity. Or, if it turns out that warming is a threat to them, by deploying local passive wind- or solar- mist-making devices.
Less seriously, what about combining geo-engineering with carbon sequestration and burial? That is, take the oxygen-depleted air left over, lighter than normal air, and trap it in huge white polythene balloons short of full inflation. These would float around for ages, surely, reflecting sunlight?
Sulphates? What if someone drilled deep into the Yellowstone lake and breached the magma chamber? Would this be like loosening the valve on a bicycle tyre compared with piercing it, create a sulphate-dispensing geyser system, and save humanity from a future super-volcanic blast?
29 June 2006 at 5:37 PM
RE: #25 - You are correct. And you can count me among those who would constitute an intense opposition group. For the record, if there is any move to do anything more than carbon taxes or other subtle things such as reforestation, I will personally oppose it with every means I have available. There is way too much uncertainty to justify doing anything specific to try and overtly “cool” the earth directly. Let’s put it this way, imagine the worst case warming scenarios being stated within the legitimate scientific community. Let’s say we observed that we were well into such a scenario. Realistically, what would happen would be increases in consumption taxes and massive efforts globally like what was done to contain the dust bowl - tree plantings and the like. Assuming that everything really is as stated by the most vocal proponents of AGW, then we’d do like we’ve done with ozone, eventually tweaking PP CO2 down and if the AGW view is true, slowly cooling the climate. However, assume, on the other hand, that there are feedbacks we do not completely understand. Let’s say we take the aggressive engineering centric route and put reflective material on ice, pumped up abyssal waters, and put reflectors into orbit. Not understanding the feedbacks, we might induce a return to extended glaciation mode. Let me share something, it would be very, very difficult to undo that. Billions would die. Insurance? Heck, there would be no insurance companies left. We’d be thrown back into prehistoric existance. There is no way I would go with the program on such an aggressive approach. My own science and engineering ethics are far too strong to allow it.
29 June 2006 at 5:54 PM
Re: 26 by Andrew Dodds asking for calculations on pumping up cold water from the ocean bottom. Idea was originally proposed for hurricane suppression. To reduce the surface temperature of the Loop Current in the Gulf of Mexico by 3.5 deg C, water from 1000 m depth must be pumped up at the rate of 1.2 million cubic meters/s. This is 4% of the Florida Current transport. Modeling is required to determine whether this upwelled water increases the Florida Current transport. I would guess that it replaces some of the Yucatan Passage surface flow with Windward Passage deep water. The Sun will reheat the water as it flows downstream, but the atmosphere will be cooled along the path. The forced upwelling will increase the thermohaline overturning.
29 June 2006 at 6:26 PM
What if you look at geoengineering from a retail, as opposed to a wholesail model?
Example. Trans-pacific airliners. 4 times a day, a jumbo takes off from Sydney (35 south), and flies basically along the tropopause for 14 hours before landing at La (or SF) (35 north).
From an economic perspective, high sulfur fuel is cheaper than low sulfur fuel. The plane is already in (or near) the stratosphere, since that is the most fuel efficient elevation at which to fly.
There are very few viable renewable energy alternatives to avgas-powered jet flight.
There are few big interest groups who would oppose this particular measure.
So why not kit out trans-equitorial planes with engines that can use high S fuel, and relax sulfur emission restrictions on this sort of travel?
If you don’t pick the low hanging fruit first, where will you get the sugar rush needed to climb the tree?
29 June 2006 at 8:49 PM
Re airline emissions and contrails:
Night flights worsen climate-change peril Jun 14, 2006
http://news.yahoo.com/s/afp/20060614/sc_afp/climatewarmingplanes
Restrictions on night flights could ease the aviation industry’s fast-growing contribution to global warming …
… during daytime, these clouds [contrails] have a cooling effect because they are white and thus reflect some of the Sun’s energy back into space.
Meteorologists at the University of Reading, southern England, estimated the radiation caused by contrails …
Night flights account for only 22 percent of Britain’s annual air traffic but contribute between 60 to 80 percent of the greenhouse effect from contrails, the scientists found.
The study appears in Nature …
… passenger travel is growing at the rate of around five per cent a year …
In addition to rescheduling night flights for the daytime, planes could diminish their contribution to global warming by changing their altitude.
A study published last year in the journal Transportation Research suggests that the regions of “ice-supersaturated” air where contrails form is only about 500 metres (1,650 feet) thick.
29 June 2006 at 9:01 PM
Perhaps you are right, Gavin. Did you look at the entire
sequence I suggested, showing its evolution?
Here’s a very different example from 08 June. What is
the explanation for this? Ship trails? Starting and
stopping like that? More likely, advertent aerosols to
keep the eastern Pacific cool, whether ship-generated or
by aircraft.
29 June 2006 at 9:34 PM
Oops, the lengthy URL for the image referred to in comment 54 would not paste in your form. Once again, it is on the Naval Research Laboratory site (www.nrlmry.navy.mil/sat_products.html) on the Southwest VIS thumbnail, in the “Previous” archive for 20060608.1630
[Response: Ship tracks would be most likely. Again, these do not always appear - it is only when the ship exhaust (with all it’s aerosols) finds itself in very humid (but not already cloudy) air. -gavin]
30 June 2006 at 12:14 AM
If you want to get rid of the carbon rather than cool the Earth, build a bunch of machines that run off solar/nuclear/heat pump that draw in air and remove the carbon, leaving little black blocks everywhere.
Could be done by bioengineered plants too.
To cool the Earth, we could float white stuff that was breathable on the oceans. Have to make it sink ten metres during storms or something…
There are a lot of people thinking about this, I think deliberate climate control will be the next big thing for us, even after we solve the GHG issue…
[Response: Little black blocks of carbon are no good. They’ll just oxidize. Bacteria are too good at respirating carbon. You’d have to bury the blocks of carbon someplace — sort of like growing trees then burying them someplace where they can’t get oxidized. Nature can do that over a few hundred million years, but to do it on a short time scale is a lot harder. Here’s a calculation you ought to do: How much energy does it take to extract CO2 from the atmosphere and pump it into a geological formation (or make it into limestone, which is more costly)? Would you be better off using that renewable energy to replace some coal burning instead? –raypierre]
30 June 2006 at 12:16 AM
My turn.
If we look at the glacial cycle as a Hamiltonian energy cycle, then we are stuck at the top of the cycle at high potential heat storage and the natural phenomena causing us to go into kinetic energy phase at mid glacial is somehow stuck. In all probability, we will continue to heat up until something gives. Something will give in a thousand years or so without GHG or in 50 years with GHG. Putting out less fossil carbon is probably not enough.
In other words, we are stuck with way too much carbon, with or without man’s foul up. Sometome soon, we will have to learn how to scrub carbon from the atmosphere and store it, for at least a few hundred years, minimum. That should be enough time for us to get a longer term handle on stabilizing carbon.
The best carbon management is to simulate nature but do it much better. Ten thousand years at these temperatures means nature wants dead, deoxygenated seas and waterways, and we should get with nature’s program and help her out. We are fighting against nature if we think this garden of eden was meant to last.
[Response: There is absolutely no scientific support for your claim that “with or without man’s foul up” we are stuck with too much carbon. Statements like this are just noise, and they don’t help the discussion. –raypierre]
30 June 2006 at 3:49 AM
Just to play devils advocate — it seems to me there must be a nuclear solution (a la the Russians).
It wouldn’t pass all your stringent requirements, but it seems it could come into play at some point (say a few centuries from now when methane hydrates start floating up to the ocean surface at a good clip). Are there good papers available concerning geo-engineering aspects of nuclear bombs? How would you apply them most effectively? Melt the East Antarctic ice sheet to increase the pressure on hydrates, introduce stratospheric aerosols, induce upwelling of nutrient rich water, something else?
Perhaps discussing possible geotechnical solutions is a good way of demonstrating to the public the magnitude of the problem.
30 June 2006 at 5:29 AM
Great article. There’s a lot of cutting edge ideas floating around
30 June 2006 at 5:46 AM
Adopting energy efficiency measure such as 1/5th energy consumption light bulbs and hybrid cars makes more sense to me than attempting geo engineering projects that will take years to setup and execute.
30 June 2006 at 6:01 AM
I believe it’s scientifically (and technically) impossible, but well…politically…
It’s quite easy to understand that complicated problems (such as global warming) can’t have simple solutions; but this GeoEngeneering thing alas would be a “good” campaign theme - and would brown-nose people on “America saves the world” theme…
Reagan’s “Star Wars” or Strategic Defense Initiative couldn’t work, but this “splendid idea” [in which Edward Teller was already implicated (hmmm…)] cost at least 30$ billion. See articles in Wikipedia and MSN Encarta for project backgrounds and figures. (#25, #51)
30 June 2006 at 7:04 AM
Re #44 — “#2) At what point do scientists project the “tipping point” point will occur? In other words, at which year/CO2 ppm will a runaway greenhouse effect comes into play?”
The runaway greenhouse effect is something that happens to a planet early in its history when a feedback between hot surface temperatures and water vapor in the atmosphere becomes self-reinforcing. The oceans boil, sunlight photodissociates the water vapor, the hydrogen escapes, the oxygen combines with rocks. Carbon dioxide that would have gone into sea sediments as limestone instead remains in the atmosphere after the water vapor is gone, keeping the temperature in the hundreds of degrees C.
It is not likely that this can be done to Earth, except possibly billions of years from now when the Sun goes off the main sequence. The main danger from global warming is not a runaway greenhouse, but disruption of agriculture and the economy and resulting property damage and famine.
-BPL
30 June 2006 at 9:54 AM
In his book, “Collapse”, Jared Diamond asks: “Will modern technology solve our problems, or is it creating new problems faster than it solves old ones?”
If we try our hand on deliberately manipulating world climate, except by reversing the ways we have affected it already, I think I know the answer…
30 June 2006 at 12:14 PM
Regarding #53 (low hanging fruit) and some of the nuclear comments:
The low-hanging fruit is currently conservation, through better system designs: homes, building, vehicles, etc., and maybe even better city/town layouts to minimize congestion and wasted time. Insulating my parent’s 1958-era split-level home has a three-year simple payback; my Prius pays off at around 85,000 miles at $2.20/gal; Clackamas High School (Clackamas, OR, https://www.usgbc.org/chapters/cascadia/clackamas.pdf ) was built to use 44% less energy than building to standard building codes, at no extra cost. That’s an example of making money right from the start. Good system design is key. The trick is to make your system need much less energy to begin with, then it becomes much easier and economical to fulfill that energy need with wind/solar/other. Las Vegas, NV is a perfect example of wasted energy (very few homes use solar power!) and where building codes should be improved….
Growth in CO2 emissions can (probably) be stopped with current technology. Reversing it may be a problem, but we can attack that after implementing the easy and economical solutions first.
As for nuclear power, it has pretty-much lost in the somewhat-free market. Even the insurance industry won’t take on the risk–at least for the first $10B or so. There are a lot of energy subsidies floating around, but still the growth rate in nuclear power is much less than for wind and solar. Nuclear power may be needed at some time in the future, but my choice would be energy efficiency first.
30 June 2006 at 2:35 PM
One geo-engineering solution to the problem of rising atmospheric levels of CO2 is to pump it into the deep ocean:
P. G. Brewer, G. Friederich, E. T. Peltzer and F. M. Orr Jr.(1999) Direct Experiments on the Ocean Disposal of Fossil Fuel CO2. Science (16 July)
Vol. 305. no. 5682, pp. 362 - 366
http://www.sciencemag.org/cgi/content/abstract/284/5416/943
See also: Cauldera and Roy (2000) Geophys. Res. Lett. 27, 225, and commentary on this article by Smith, H.J. (2000)Ocean Dumping of CO2. Science (4 February)
Vol. 287. no. 5454, p. 769.
http://www.sciencemag.org/cgi/content/summary/287/5454/769a?
This raises some obvious biological concerns:
B. A. Seibel and P. J. Walsh (2001) Potential Impacts of CO2 Injection on Deep-Sea Biota. Science (12 October) Vol. 294. no. 5541, pp. 319 - 320 http://www.sciencemag.org/cgi/content/full/294/5541/319
[See also the Royal Society of the UK statement on ocean acidification due to rising atmospheric CO2 levels, June 2005; PDF available for free online at the Royal Society website)
Here are some alternative ideas:
K. S. Lackner (2003) A Guide to CO2 Sequestration. Science (3 June)Vol. 300. no. 5626, pp. 1677 - 1678
Abstract: Carbon capture and storage (or sequestration) is receiving increasing attention as one tool for reducing carbon dioxide concentrations in the atmosphere. In his Perspective, Lackner discusses the advantages and disadvantages of different methods of carbon sequestration. He advises against sequestration in environmentally active carbon pools such as the oceans, because it may merely trade one environmental problem for another. Better sequestration options include underground injection and (possibly underground) neutralization. Taking into account carbon capture, transport, and storage, the author concludes that in the short and medium term, sequestration would almost certainly be cheaper than a full transition to nuclear, wind, or solar energy.
http://www.sciencemag.org/cgi/content/summary/300/5626/1677
Re: #47 All of the estimates I have seen for emissions of anthropogenic CO2 into the atmosphere (5-7 billion metric tons per year; IPCC 2001 report) include cement production, but this is only a small % of the total.
30 June 2006 at 5:45 PM
My understanding is that we’ve already passed the “tipping point”. Read Science at:
http://www.sciencemag.org/cgi/content/summary/311/5768/1673
“A central feature of this long baseline is this: At no time in at least the past 10 million years has the atmospheric concentration of CO2 exceeded the present value of 380 ppmv. At this time in the Miocene, there were no major ice sheets in Greenland, sea level was several meters higher than today’s (envision a very skinny Florida), and temperatures were several degrees higher.”
This is just with 380 ppm, already higher than we’ve seen in 10 million years. We will pass 400 soon, and only with the most stringent controls could we hope to level off by 550 ppm, twice the pre-industrial level.
The truth is that we are already committed to enough warming to melt the Greenland ice sheets and flood Florida and all coastal cities, exactly the scenario depicted in Gore’s documentary. The tipping point has been passed.
The only solution at this point is technological remediation. It may be unpalatable, but we really don’t have any choice. CO2 levels are already too high and have “baked in” disastrous sea level rise. It’s only a matter of time at this point. In order to save our civilization we have to either remove CO2 from the atmosphere, or else take steps to reduce forcings in other ways.
And the truth is, we’re already manipulating the climate; not just via CO2, but in the wide variety of ways that mankind changes and influences the globe. It’s time that we recognize this and begin dealing with things on a conscious and intentional level. It is a myth that we can live in a “natural” world that is somehow free of human influence. Humanity is rapidly becoming a dominant force in many aspects of the planetary ecosystem, and we can no longer afford to pretend otherwise.
Here is Teller’s paper from Livermore Labs:
http://www.llnl.gov/global-warm/148012.pdf
He discusses both stratospheric particles (not necessarily sulfates) as well as space based shields. Those looking for more details on these proposals, like total mass requirements, will find some information here. Teller estimates costs of a few billion dollars a year starting around 2050. He points out that a ONE-TIME lump sum payment of a billion dollars invested for 50 years would generate enough interest to sustain the program indefinitely.
UCI physicist Gregory Benford further discusses these ideas in this podcast:
http://www.desmogblog.com/audio/gregory-benford-podcast
He suggests a pilot program at a cost of 1/10 of this, $100 million/year, targeted at protecting the arctic region and reducing the loss of polar ice. This way we could get experience with the technology and deal with any problems that arise before committing to a full scale effort.
If these kinds of numbers hold up, remediation will be far cheaper economically than conservation could ever hope to be. If global warming can be substantially dealt with by a one time charge of fifteen cents per person, we need to rethink our strategies and our emphasis.
30 June 2006 at 6:30 PM
Re 67: Start geoengineering:
“And the truth is, we’re already manipulating the climate; not just via CO2, but in the wide variety of ways that mankind changes and influences the globe. It’s time that we recognize this and begin dealing with things on a conscious and intentional level. It is a myth that we can live in a “natural” world that is somehow free of human influence. Humanity is rapidly becoming a dominant force in many aspects of the planetary ecosystem, and we can no longer afford to pretend otherwise.”
A. I am opposed to geoengineering projects, until we have reduced CO2 to pre-industrial levels and then realise we still have a problem. I realise this is considered “impractical,” but only because of a commitment to doing things as they are currently done.
B. Similarly, we have other things to do in an attempt to get the planet back in some sort of equilibrium that supports human life - and all the other lives, plant and animal, that we depend upon. Things like reduce overpopulation, pollution, loss of biodiversity, etc.
C. Humanity is not “becoming a dominant force,” we are one. The only people “pretending” we are not are denialists, as far as I can tell.
D. We have to live in a “natural world,” but of course it will not be free of human influence, any more than it is free of influence by deer and ants. The question is whether, at this ‘tipping point’ in human history, we make a conscious choice to return to living sustainably, or continue on our current path, where we believe we have the wisdom to control the planet’s ecosystem. History shows very clearly that we lack sufficient knowledge, wisdom, or humanity to be trusted with global systems.
“If these kinds of numbers hold up, remediation will be far cheaper economically than conservation could ever hope to be.”
Which pretty much proves that the numbers are wrong. The only way spending money costs less than not spending money is when crooked politicians do it. This is because they subsidize certain costs, distorting the true costs.
30 June 2006 at 6:35 PM
RealClimate Staff,
On the general topic of geo-engineering, have any studies been done to determine the effects of massive worldwide irrigation techniques on local or global climate systems? My stepfather recently suggested this as a possibly significant factor in global change, but this was merely over dinner and wine so I’m not sure to the extent that he or others have substantiated such claims. His field of expertise is soil-plant-atmosphere processes in the Arctic, along with complex systems (well, as far as I know). Being a lay-person I can’t attest to the validity of his theory, but it does seem to intuitively make sense. Any thoughts?
30 June 2006 at 7:03 PM
#67: “It’s time that we recognize this and begin dealing with things on a conscious and intentional level.”
I imagine an alcoholic who has been told by his doctor that his alcohol consumption has already damaged his liver and he needs to stop drinking alcohol completely or he will die. Instead, he decides that he will take conscious and intentional control of the functioning of his liver through various technological interventions, and since he is so much smarter than his dumb old liver, he will be able to improve its functioning so it can handle the alcohol and he can go on drinking.
30 June 2006 at 11:21 PM
Just a thought about the ocean overturning idea: how much methane would escape from thawing clathrates if we raised deep ocean temperatures even a few degrees, let alone 15?! An awful lot I think…
1 July 2006 at 12:46 AM
Re:71. My scheme for pumping up cold water requires much massive OTEC hardware to make a very small change in the surface temperature. There will be no increase in bottom temperature. Where did the 15 degree estimate come from?
1 July 2006 at 12:46 AM
Re:71. My scheme for pumping up cold water requires much massive OTEC hardware to make a very small change in the surface temperature. There will be no increase in bottom temperature. Where did the 15 degree estimate come from?
1 July 2006 at 2:51 AM
Richard, the deep ocean temperature increase is already documented.
Google will turn up examples; here’s one from a long time series; see the website from which this comes for more.
http://www.fou.uib.no/fd/1997/f/406001/IMG00004.GIF
1 July 2006 at 4:31 AM
“meteor, or even several thousand meteors, would not have enough cross section area to block the amount of sunlight you’d need to block.”
Gavin, how big of meteors are we talking about?
1 July 2006 at 10:40 AM
Hal,
That podcast is awesome. Seems too good to be true.
1 July 2006 at 1:04 PM
To me, the most hazardous aspect of the artificial stratospheric aerosol idea is the mismatch in time scales between aerosols and CO2. A good bit of the anthropogenic CO2 will stay in the atmosphere for a thousand years, whereas the aerosols will need to be renewed every few years. That means one is making the assumption that the world will remain rich enough and politically stable enough continuously over the next millennium to keep with the program. If there’s a world depression, or a global war that disrupts international cooperation for a few years, the planet would be hit with the full radiative forcing of all that CO2 in the space of just a few years. Talk about abrupt change!
The sulfate scheme is a lot like putting nuclear waste above ground in Manhattan, in a plywood shelter that needs to be rebuilt every two or three years to keep it from rotting.
1 July 2006 at 2:29 PM
Richard, in #72:
I got that 15o number from Andrew Dodds comment in #26, no opinion on the accuracy of the calculation. But regardless of the exact number the principals behind your idea require that warmer water replaces the cold water you are drawing up, no? You are taking heat out of the lower atmosphere and out of the upper oceans, it must go somewhere.
1 July 2006 at 2:37 PM
Sulphate aerosol cooling need not be maintained indefinately. The danger of the current climate change is its rapidity. Perhaps if we just slowed the warming, spread it out over a few centuries it would not be such a big problem, then the aerosols could be phased out. So now we only need political stability and cheap energy for maybe five hundred years, not a millemium, no problem, right?
Oh yeah. There’s that darn ocean acidification again…so eat less sushi.
1 July 2006 at 6:18 PM
This ongoing discussion of sulphate aerosol cooling is getting too confusing because some replies are really ironic comments (meant) to dismiss the idea and that is a good thing. But,some of us may be trying to follow the logic of loading aerosols into the stratosphere.
I’d like to focus on three aspects of artificial stratospheric aerosol geoengineering idea that could help move past this seemingly nonsensical idea.
The residence time of sulphates is days to several weeks. When dissipated as sulfuric acid oceans, lakes and forests suffer unacceptable damage — intentionally increasing acidification of oceans sounds suicidal.
The source of the sulphates will likely be coal or heavy oil. What? more atmospheric CO2 to remedy climate forcing.
Finally, greenhouse warming warms the troposphere and thereby increases its depth and effectivly cools the stratopshere. Why then, would we think of further cooling the stratopshere and thereby decrease the ozone level in the statosphere over the arctic?
Can anyone help me understand the last point more clearly?
1 July 2006 at 10:03 PM
Anytime an acid chemically reacts with a carbonate compound the products are a salt, water , and carbon dioxide. Therefore, if sulfate aerosols are added to the atmosphere and generate sulfuric acid rain, as this acid reacts with limestone (calcium carbonate), the products would be calcium sulfate, water and CO2. Ultimately, you would be accelerating the chemical weathering of limestone and further INCREASING the CO2 content of the atmosphere. The carbon cycle would be in a kind of overdrive. CO2 levels could only remain stable if biological processes accelerated the carbon sequestration process to match the accelerated chemical weathering of limestone. A little inorganic precipitation of carbonates might augment the biological process, but I can’t imagine that any of these processes could match the accelerated chemical weathering of limestone which would be caused by seeding the atmosphere with acid causing aerosols. Why am I not seeing any hypotheses like this in the popular literature. Can someone please comment?
1 July 2006 at 10:35 PM
Well, I am not very impressed by the idea of just blocking sunlight as a GW solution by any means, hence the ironic comments, but my point is still valid. We do not need to hold the temperature where it is now, we just have to keep it from moving too fast. Hence the notion that any such solution can eventually be phased out and need not remain in place forever.
John, your last point: I think the cooling effect is at the earth’s surface, not in the stratosphere. Sulphates block visible light, which the stratosphere is transparent to. If anything, I’d expect some stratospheric warming from aerosols absorbing sunlight.
1 July 2006 at 11:49 PM
Re 65
“Las Vegas, NV is a perfect example of wasted energy (very few homes use solar power!) and where building codes should be improved….”
Ditto For Florida. Incidentally I drive a 1993 Suzuki Swift with a manual transmission it gets over 45 mpg on the highway at 65 mph with the AC on. If I reduce my speed to 55 mph and put the AC on low and am careful with aceleration and braking I can get almost 50 mpg with this car. That is comparable to most new hybrids with the exception of the Prius and the Honda Insight which can get better gas mileage.
So before we start with geo-engineering projects I would like to see a lot more done with already existing off the shelf technology and conservation.
It may be that if there isn’t a voluntary step in this direction then it has to be mandated. I don’t recall that my quality of life was significantly diminished back in the days when we had a 55mph speed limit. I calculate my yearly CO2 output for the driving that I do to be around 4000 lbs. I know I can find ways to do even better than that.
If everybody took mass transit when possible, walked a little more, rode their bicycles for short trips, turned down their thermostats, put their airconditioners on low and bought energy efficient appliances and lightbulbs, I really don’t think it would significantly alter our quality of life.
It would however have an immediate quantitative impact on the reduction of CO2 being released into the atmosphere.
So until I see the majority of the population adopting measures of conservation I too will be in vocal opposition to any geo-engineering projects.
I know this idea won’t fly but how about attaching a fuel surcharge to the amount of CO2 a private vehicle produces, for example if you drive a small hybrid you pay $2.00 per gallon at the pump, if you drive a top of the line gas guzzling SUV you pay $10.00 a gallon for the same fuel. If you can afford the luxury than pay for it. Don’t expect the rest of society to subsidize your comfort our expense.
2 July 2006 at 12:24 AM
The depth of the hostility towards the whole idea of geoengineering seems breathtaking to me. One may criticize a particular scheme as good or bad, but nowhere has it been proven that any and all geoengineering schemes are evil or worthless. There is a fear that such schemes may be regarded as a substitute for solving the underlying problems, and this is understandable; but this need not be so, and the underlying problems are not going to be solved overnight as some commenters too glibly suggest. I would say that 40-60 years is a reasonable minimum time to expect a transformation of society’s energy base to happen (terabucks’ worth of infrastructure will have to be replaced); but what about all the GHGs that will yet be dumped into the air in the meantime? Is it more virtuous just passively to accept the consequences of, say, 550-750 ppm carbon dioxide than to try to contain the thermal consequences until the levels can be brought back down? Where is the line between ideology and common sense?
2 July 2006 at 12:58 AM
Re #83
Hecker,
How is a decision made globally about which fix to try? And if a geo-engineering fix turns out not to work and ends up making the situation worse, will it be possible to repair the damage? And what will it cost? And who will pay for it? Those are some of my concerns.
2 July 2006 at 1:10 AM
Re:#83
I agree, but: geoengineering is a brand-new idea, and since earth is a large and complex system, there’s an immense amount we don’t know about the consequences. Noone would argue that surgery isn’t a life-saving option for many patients. But in the *early* days of surgery, a common outcome was: the operation was a success, and the patient died.
2 July 2006 at 2:14 AM
I’m debating climate change with my parents.
Could you please give me the name of the scientist who reported on the fact that the glaciers were getting bigger on the inside, but were melting on the outside. I heard on a radio show that he was hoping to put a “stop use” on the people who were cherry picking his report to say that the glaciers were getting bigger.
Any info on this would be helpful in getting my folks to listen up to the dangers their grandchildren may be facing.
Best regards,
Maggie
2 July 2006 at 3:30 AM
Maggie, here:
www.factcheck.org/article395.html
Scientist to CEI: You Used My Research To “Confuse and Mislead …
An editor of Science also said the ads misrepresent the findings of that study as well as a … The CEI ad “Glacier” quotes two studies in Science magazine, …
Here’s how I found that:
I searched google for: +glacier +scientist +ad +misrepresent
http://www.google.com/search?q=%2Bglacier+%2Bscientist+%2Bad+%2Bmisrepresent&start=0
That is the first item in the results
2 July 2006 at 3:40 AM
Ray, you were interested in the idea of setting up radiators tuned to the infrared frequencies in which the atmosphere is transparent (that IEEE paper discussed a while back).
Perhaps there’s a practical way to do it — you’ve seen the so-called ‘day-glow’ paints that are pure molecules reflecting green and orange and yellow, that are optically very bright because (I’m told) they are reflecting only one wavelength or narrow band, rather than being a mixture of different colors as pigments usually are produced.
We need a pigment that reflects efficiently in the useful infrared range, a pure paint color, for painting roofs and roads.
But — we know about ‘red tide’ blooms.
So, let’s ask someone to try to bioengineer by modifying some of our existing sea life an ‘infrared tide’ organism that will reflect from the sea surface in one of those useful frequency ranges, and
— eat up CO2
— thrive on the surface in an acidifying ocean
— reflect infrared out into space through the transparent window
— and die off and sink fairly fast so sequester material.
=== possibly producing some nice stable dense plastic ….
Of course this leads awful close to the nanotech ‘gray goo’ disaster scenario. Maybe gray goo reflects infrared (sigh).
[Response: I was much taken with the infrared transformer idea mainly because it turns into such a nice exam problem on radiative transfer. On a little reflection (no pun intended), I realized that it would be a lot simpler to just increase visible albedo and keep sunlight from turning to IR in the first place. Note that just reflecting thermal IR won’t do you much good. The original scheme relied on intercepting upwelling broadband IR and converting it to IR in the IR window channels where the atmosphere is fairly transparent. That’s a lot to ask of algae, bioengineered though they may be. Now, one could imagine bioengineering algae to increase ocean reflectivity, maybe even by emitting more DMSO to trigger low cloud production. However, talk about losing control — releasing genetically modified organisms into the environment would be a hard genie to put back in the bottle. The stratospheric aerosol idea looks benign by comparison.
Some might fault Crutzen for even discussing this, since it opens the door to all sorts of abuse where people could be left with the impression that we don’t need to do anything to reduce CO2 emissions since we can always engineer our way out of the problem. I myself think that there are only a very few cases where the spirit of free scientific inquiry should be quashed, and that if scientists have to start thinking to defensively about their curiosity-driven research we’ll all lose. For that matter, if people start thinking about the reality of needing to sustain a livable climate by needing to maintain a worldwide campaign to renew stratospheric aerosols annually, that might be an eye-opener and start to make the whole thing more real. There are cases where I think scientists need to refrain from lines of research they’d otherwise be interested in pursuing, but I don’t think this is one of those cases. Teller’s drive to the H-bomb –based as much on his desire to prove his point by building his toy, as by his politics — is a cases where one could argue that restraint would have been desirable. Developing miniature nukes or neutron bombs in the US is another, since one could argue that if we don’t build such things nobody else has the research capability to do it. Similarly, I don’t think scientists should be messing around with genetically-engineered bioweapons. People should be free to think about all sorts of wild and not so wild geoengineering proposals, as long as they don’t get oversold as a solution. The reason I don’t like the high-CO2 plus high Sulfate Aerosol proposal is that it seems like balancing a load of bricks on a broomstick and keeping the thing from toppling by giving it a nudge in the right direction each year. Better to solve the problem by taking away the bricks instead — or not putting them up there in the first place. –raypierre]
2 July 2006 at 4:42 AM
Re#84
Maggie, follow the link below.
http://www.realclimate.org/index.php/archives/2006/05/thank-you-for-emitting/
Within that article follow the “Update link”.
2 July 2006 at 8:16 AM
I for one am not hostile to the idea of geo-engineering per se, only concerned that it might be held up as another excuse for maintaining the status quo by those that have a vested interest in maintaining it.
I think # 70 said it quite well by comparing the situation to that of an alcoholic looking for a technological fix to her problem.
I have no hostility toward the idea of liver transplants either, there are times when they may be necessary and its good to know the technology is available. Though the common sense solution would be to stop denying that we have a problem and cut down on the margaritas. That doesn’t mean the liver transplant won’t still be necessary.
When confronted with the truth of their problem the alcoholic usually denies it and tends to become hostile towards towards the person who tells them they should stop drinking.
I think the fact that we are even begining to discuss geo-engineering as a solution to global warming at least makes it harder to deny that we have a problem.
2 July 2006 at 10:17 AM
Just to remind everyone about http://www.tinyurl.com which boils your loooong URLs down to a small, easily pasted fragment.
2 July 2006 at 1:50 PM
Thanks for the help, you’re all dreamy!
2 July 2006 at 2:11 PM
[OT] About tinyurl etc, I don’t like not knowing what I am clicking on. I acknowledge the utility of a short, non-comma or other weird character filled URL for all the various ways blogs are written and read, but I rarely follow a tinyurl unless the person offering it has included an indication of where it will take me. (eg “check this independent.co.uk article here: tinyurl.com/ewkirq.html”)
2 July 2006 at 8:53 PM
This post brings out an important point, the inherently conservative nature of those who worry about climate change. Typically messing about with the environment has been a favorite of both the communists and the industrialists, groups who thought the road to progress was through industrial development. Environmentalism’s roots are among rural people, farmers and landowners.
The rightward shift of evangelicals is important, because part of the price they pay to their new party is to abandon stewardship, a very important part of all religion. We are seeing this play out today with the beginning of pushback. Right now there are at least two competing petitions. The one on the nothing to worry about side has been signed by Roy Spencer and S. Fred Singer.
The editors may want to cut the last paragraph
2 July 2006 at 8:56 PM
83 & 84:
I definitely agree that many conservation measures don’t require anyone to give up their lifestyle. And as better home, building, and vehicle designs become more prevalent, we will be getting even more services from the money we spend on energy. Regarding encouraging people to change behavior, I think consumers should be able to buy whatever vehicle they want, but I would suggest that they have to pay the external costs up front when they buy a vehicle: i.e., up front fees for health care costs (asthma, etc.), DOD costs (fighting for oil), global warming costs (this is a more difficult one to estimate), and pollution costs (CO, Unburned HC, NOx, SOx). This would be like taking responsibility for your actions. These fees could be ‘recycled’ into rebates for people to buy the top (say) five fuel-efficient vehicles. Similar measures could be enacted for homes and buildings.
84: It may appear that some of us are hostile to geo-engineering proposals, but that is only because we (global “we”) need to be spending our money on the best buys first. Example: when the NE had the large blackout several years ago, many of our wonderful senators and congressman were tripping over themeselves to give $100 million to the energy industry to update the ‘grid.’ As a consumer, I would be willing to bet that if a complete economic/engineering analysis were done, that amount of money would be better spent on making all the homes and businesses involved, more energy efficient. That way, the amount of electricity flowing over the grid would be reduced. This not only gives the grid a longer life, but it reduces people’s electric bills, pollution, CO2, etc. More money is now available for the next step in energy efficiency, whatever that may be.
Demand is key…consumers have the ultimate control, if we are just smart enough to use it.
2 July 2006 at 10:02 PM
>Response: There is absolutely no scientific support for your claim that “with or without man’s foul up” we are stuck with too much carbon. Statements like this are just noise, and they don’t help the discussion. –raypierre
True and I gave links (in the comments of another post) to some places you (collective realclimate - though including you singular) have refuted it.. But I think it is the next major denier talking point. So a really concise really clear rebuttal would be welcome. I wonder if the ill considered blog could do one.
3 July 2006 at 4:59 AM
Re: 72, 73:
If you pump cold water up to cool the planet, then that cold water will become warm. Furthermore, since in order to offset AGW you must have a net absorbtion of heat (of an amount equal to the extra AGW forcing) into the oceans, you will end up warming the oceans. You can’t get around this without seriously violating the laws of physics.
I chose 15K as a practical number for the temperature increase you could expect for a unit of water. Make that 1K and your scheme breaks down in just 70 years; the environmental side effects of overturning the entire ocean in 70 years would be fairly catastrophic, I expect.
[Response: Here’s a nice little calculation for people to try their hands at. Consider one square meter of deep ocean. Compute the energy needed to lift M kilograms per second of cold water from the bottom to the surface in that square meter column (using just the potential energy, ignoring possible frictional dissipation in pipes, etc.). Then compute the effective cooling rate of the cold water flux, in Watts (which is M * Cp * dT, where dT is the temperature difference between the surface water that gets pushed aside and the cold water that replaces it). How does this flux compare with the energy flux needed to do the pumping? Is this a winner or loser? It’s like an engineered hurricane, so far as mixing is concerned. Of course, you can’t do this forever since ultimately the deep water will warm up, but you could do it for a long time before you run out of temperature gradient. (Bonus points for figuring out how long, based on choosing M so as to offset 4 W/m**2 from CO2). –raypierre]
3 July 2006 at 1:10 PM
RE: #82 Coby, thank you for the insight on aeorsols and cooling the stratosphere.
If this thread has helped to shoot the legs off the idea of injecting sulphate aerosols into the atmosphere, could I take another shot at understanding the stratoshpere cooling concern — and this from the standpoint of launching reflective mirrors into orbit to cool the earth’s surface.
As you said, in #82:
John, your last point: I think the cooling effect is at the earth’s surface, not in the stratosphere. Sulphates block visible light, which the stratosphere is transparent to. If anything, I’d expect some stratospheric warming from aerosols absorbing sunlight.
You helped me understand transparency of the stratosphere; but it can be heated by UV absorption, primarily in the ozone (O3) layer.
Then from — http://earthobservatory.nasa.gov/Study/Tango/
I read the following:
“Ozone’s impact on climate consists primarily of changes in temperature. The more ozone in a given parcel of air, the more heat it retains. Ozone generates heat in the stratosphere, both by absorbing the sun’s ultraviolet radiation and by absorbing upwelling infrared radiation from the lower atmosphere (troposphere). Consequently, decreased ozone in the stratosphere results in lower temperatures. Observations show that over recent decades, the mid to upper stratosphere (from 30 to 50 km above the Earth’s surface) has cooled by 1° to 6° C (2° to 11° F). This stratospheric cooling has taken place at the same time that greenhouse gas amounts in the lower atmosphere (troposphere) have risen. The two phenomena may be linked.”
So, any attempt to reflect sun light back into space can have the effect of cooling the stratosphere and diminishing ozone concentration. That’s a bad thing. Am I getting it?
3 July 2006 at 1:57 PM
“Those who refuse to use arithmetic are doomed to failure.”
3 July 2006 at 4:09 PM
At my workplace lunchroom there is one of those cartoon-a-day desk calendars, only this one is a collection of proverbs from many cultures. The one for tomorrow (4 July) is interesting when thinking about people arguing that global warming has a “big project” solution:
“What you wish you readily believe”
(Hungarian)
3 July 2006 at 4:29 PM
“Here’s a nice little calculation for people to try their hands at…”
And once you figure out that problem, you can try estimating the likely impact of that warm, unstratified ocean on marine phytoplankton primary productivity that currently provides about 40-50% of our atmosphere’s oxygen.
4 July 2006 at 7:16 AM
Response to comments made about geoengineering article in NY Times.
Below I have responded to some of the comments related to the Times article and the subject of geoengineering. I coauthored the plan to cover the deserts with white plastic and was quoted in the article. I also want to point out that many of the proposed solutions mentioned in the article have been discussed elsewhere in a kind of periodic reinventing of the wheel process that seems to have occurred every few years since the mid 1980’s when the problem of global climate change first began to be taken seriously. See the links and books below for a pretty thorough coverage of the topic.
http://forum.europa.eu.int/Public/irc/env/action_climat/library?l=/geoengineering_optionspd/_EN_1.0_&a=i
http://www.tyndall.ac.uk/events/past_events/cmi.shtml
http://reason.com/9711/fe.benford.shtml
http://www.chooseclimate.org/cleng/mf.html
http://www.newruskincollege.com/gorbachevbushartificialcloudsinstitutenewruskincollegecom/id7.html
http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=1849&start=1
http://newton.nap.edu/books/0309043867/html/433.html
R.G. Watts, Engineering Response to Global Climate Change, Lewis Publishers, CRC, New York, 1997.
J.A. Edmonds et al., Future Atmospheric Carbon Dioxide Scenarios and Limitation Strategies, Noyes Publications, Park Ridge, New Jersey, 1986.
What is significant about the Times article to me is that Dr. Ralph Cicerone, president of NAS is now back on the side of promoting research in this area. Like so many scientists involved with the climate change problem, he has been to say the least, conflicted on the idea of geoengineering. In the early 90s he proposed and later changed his mind about a plan to inject large quantities of hydrocarbon gases into the stratosphere to solve the ozone depletion problem. Later in the decade, he came out against doing any geoengineering work. So for him to do a 180 on this along with Paul Crutzen picking up the Teller ball and starting to run either indicates we have reached a tipping point of sorts for geoengineering or the end of another cycle of debate on the issue.
For anything useful to come out of a debate on geoengineering, there must be serious research funding. I would doubt that more than $25 million has been spent in total since 1980 in government, academic and industry studies, hardly enough to answer any questions. The main funding agencies in the U.S: DOE, EPA, NSF, NOAA