This Week’s Finds (Week 310)

I first encountered Gregory Benford through his science fiction novels: my favorite is probably In the Ocean of Night.

Later I learned that he’s an astrophysicist at U.C. Irvine, not too far from Riverside where I teach. But I only actually met him through my wife. She sometimes teaches courses on science fiction, and like Benford, she has some involvement with the Eaton Collection at U.C. Riverside—the largest publicly accessible SF library in the world. So, I was bound to eventually bump into him.

When I did, I learned about his work on electromagnetic filaments near the center of our galaxy—see “week252″ for more. I also learned he was seriously interested in climate change, and that he was going to the Asilomar International Conference on Climate Intervention Technologies—a controversial get-together designed to hammer out some policies for research on geoengineering.

Benford is a friendly but no-nonsense guy. Recently he sent me an email mentioning my blog, and said: "Your discussions on what to do are good, though general, while what we need is specifics NOW." Since I’d been meaning to interview him for a while, this gave me the perfect opening.

JB: You’ve been thinking about the future for a long time, since that’s part of your job as a science fiction writer.  For example, you’ve written a whole series about the expansion of human life through the galaxy.  From this grand perspective, global warming might seem like an annoying little road-bump before the ride even gets started.  How did you get interested in global warming? 

GB: I liked writing about the far horizons of our human prospect; it’s fun. But to get even above the envelope of our atmosphere in a sustained way, we have to stabilize the planet. Before we take on the galaxy, let’s do a smaller problem .

JB: Good point. We can’t all ship on out of here, and the way it’s going now, maybe none of us will, unless we get our act together.

Can you remember something that made you think "Wow, global warming is a really serious problem"?  As you know, not everyone is convinced yet.

GB: I looked at the migration of animals and then the steadily northward march of trees. They don’t read newspapers—the trees become newspapers—so their opinion matters more. Plus the retreat of the Arctic Sea ice in summer, the region of the world most endangered by the changes coming. I first focused on carbon capture using the CROPS method. I’m the guy who first proposed screening the Arctic with aerosols to cool it in summer.

JB: Let’s talk about each in turn. "CROPS" stands for Crop Residue Oceanic Permanent Sequestration. The idea sounds pretty simple: dump a lot of crop residues—stalks, leaves and stuff—on the deep ocean floor. That way, we’d be letting plants suck CO2 out of the atmosphere for us.

GB: Agriculture is the world’s biggest industry; we should take advantage of it. That’s what gave Bob Metzger and me the idea: collect farm waste and sink it to the bottom of the ocean, whence it shall not return for 1000 years. Cheap, easy, doable right now.

JB: But we have to think about what’ll happen if we dump all that stuff into the ocean, right? After all, the USA alone creates half a gigatonne of crop residues each year, and world-wide it’s ten times that. I’m getting these numbers from your papers:

• Robert A. Metzger and Gregory Benford, Sequestering of atmospheric carbon through permanent disposal of crop residue, Climatic Change 49 (2001), 11-19.

• Stuart E. Strand and Gregory Benford, Ocean sequestration of crop residue carbon: recycling fossil fuel carbon back to deep sediments, Environmental Science and Technology 43 (2009), 1000-1007.

Since we’re burning over 7 gigatonnes of carbon each year, burying 5 gigatonnes of crop waste is just enough to make a serious dent in our carbon footprint. But what’ll that much junk do at the bottom of the ocean?

GB: We’re testing the chemistry of how farm waste interacts with deep ocean sites offshore Monterey Bay right now. Here’s a picture of a bale 3.2 km down:

JB: I’m sure our audience will have more questions about this… but the answers to some are in your papers, and I want to spend a bit more time on your proposal to screen the Arctic. There’s a good summary here:

• Gregory Benford, Climate controls, Reason Magazine, November 1997.

But in brief, it sounds like you want to test the results of spraying a lot of micron-sized dust into the atmosphere above the Arctic Sea during the summer. You suggest diatomaceous earth as an option, because it’s chemically inert: just silica. How would the test work, exactly, and what would you hope to learn?

GB: The US has inflight refueling aircraft such as the KC-10 Extender that with minor changes spread aerosols at relevant altitudes, and pilots who know how to fly big sausages filled with fluids.



Rather than diatomaceous earth, I now think ordinary SO2 or H2S will work, if there’s enough water at the relevant altitudes. Turns out the pollutant issue is minor, since it would be only a percent or so of the SO2 already in the Arctic troposphere. The point is to spread aerosols to diminish sunlight and look for signals of less sunlight on the ground, changes in sea ice loss rates in summer, etc. It’s hard to do a weak experiment and be sure you see a signal. Doing regional experiments helps, so you can see a signal before the aerosols spread much. It’s a first step, an in-principle experiment.

Simulations show it can stop the sea ice retreat. Many fear if we lose the sea ice in summer ocean currents may alter; nobody really knows. We do know that the tundra is softening as it thaws, making roads impassible and shifting many wildlife patterns, with unforeseen long term effects. Cooling the Arctic back to, say, the 1950 summer temperature range would cost maybe $300 million/year, i.e., nothing. Simulations show to do this globally, offsetting say CO2 at 500 ppm, might cost a few billion dollars per year. That doesn’t help ocean acidification, but it’s a start on the temperature problem.

JB: There’s an interesting blog on Arctic political, military and business developments:

• Anatoly Karlin, Arctic Progress.

Here’s the overview:

Today, global warming is kick-starting Arctic history. The accelerating melting of Arctic sea ice promises to open up circumpolar shipping routes, halving the time needed for container ships and tankers to travel between Europe and East Asia. As the ice and permafrost retreat, the physical infrastructure of industrial civilization will overspread the region [...]. The four major populated regions encircling the Arctic Ocean—Alaska, Russia, Canada, Scandinavia (ARCS)—are all set for massive economic expansion in the decades ahead. But the flowering of industrial civilization’s fruit in the thawing Far North carries within it the seeds of its perils. The opening of the Arctic is making border disputes more serious and spurring Russian and Canadian military buildups in the region. The warming of the Arctic could also accelerate global warming—and not just through the increased economic activity and hydrocarbons production. One disturbing possibility is that the melting of the Siberian permafrost will release vast amounts of methane, a greenhouse gas that is far more potent than CO2, into the atmosphere, and tip the world into runaway climate change.

But anyway, unlike many people, I’m not mentioning risks associated with geoengineering in order to instantly foreclose discussion of it, because I know there are also risks associated with not doing it. If we rule out doing anything really new because it’s too expensive or too risky, we might wind up locking ourselves in a "business as usual" scenario. And that could be even more risky—and perhaps ultimately more expensive as well.

GB: Yes, no end of problems. Most impressive is how they look like a descending spiral, self-reinforcing.

Certainly countries now scramble for Arctic resources, trade routes opened by thawing—all likely to become hotly contested strategic assets. So too melting Himalayan glaciers can perhaps trigger "water wars" in Asia—especially India and China, two vast lands of very different cultures. Then, coming on later, come rising sea levels. Florida starts to go away. The list is endless and therefore uninteresting. We all saturate.

So droughts, floods, desertification, hammering weather events—they draw ever less attention as they grow more common. Maybe Darfur is the first "climate war." It’s plausible.

The Arctic is the canary in the climate coalmine. Cutting CO2 emissions will take far too long to significantly affect the sea ice. Permafrost melts there, giving additional positive feedback. Methane release from the not-so-perma-frost is the most dangerous amplifying feedback in the entire carbon cycle. As John Nissen has repeatedly called attention to, the permafrost permamelt holds a staggering 1.5 trillion tons of frozen carbon, about twice as much carbon as is in the atmosphere. Much would emerge as methane. Methane is 25 times as potent a heat-trapping gas as CO2 over a century, and 72 times as potent over the first 20 years! The carbon is locked in a freezer. Yet that’s the part of the planet warming up the fastest. Really bad news:

• Kevin Schaefer, Tingjun Zhang, Lori Bruhwiler and Andrew P. Barrett, Amount and timing of permafrost carbon release in response to climate warming, Tellus, 15 February 2011.

Abstract: The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO2 concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate. We use surface weather from three global climate models based on the moderate warming, A1B Intergovernmental Panel on Climate Change emissions scenario and the SiBCASA land surface model to estimate the strength and timing of the PCF and associated uncertainty. By 2200, we predict a 29-59% decrease in permafrost area and a 53-97 cm increase in active layer thickness. By 2200, the PCF strength in terms of cumulative permafrost carbon flux to the atmosphere is 190±64 gigatonnes of carbon. This estimate may be low because it does not account for amplified surface warming due to the PCF itself and excludes some discontinuous permafrost regions where SiBCASA did not simulate permafrost. We predict that the PCF will change the arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42-88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration.

Particularly interesting is the slowing of thermohaline circulation.  In John Nissen’s "two scenarios" work there’s an uncomfortably cool future—if the Gulf Stream were to be diverted by meltwater flowing into NW Atlantic. There’s also an unbearably hot future, if the methane from not-so-permafrost and causes global warming to spiral out of control. So we have a terrifying menu.

JB: I recently interviewed Nathan Urban here. He explained a paper where he estimated the chance that the Atlantic current you’re talking about could collapse. (Technically, it’s the Atlantic meridional overturning circulation, not quite the same as the Gulf Stream.) They got a 10% chance of it happening in two centuries, assuming a business as usual scenario. But there are a lot of uncertainties in the modeling here.

Back to geoengineering. I want to talk about some ways it could go wrong, how soon we’d find out if it did, and what we could do then.

For example, you say we’ll put sulfur dioxide in the atmosphere below 15 kilometers, and most of the ozone is above 20 kilometers. That’s good, but then I wonder how much sulfur dioxide will diffuse upwards. As the name suggests, the stratosphere is "stratified" —there’s not much turbulence. That’s reassuring. But I guess one reason to do experiments is to see exactly what really happens.

GB: It’s really the only way to go forward. I fear we are now in the Decade of Dithering that will end with the deadly 2020s. Only then will experiments get done and issues engaged. All else, as tempting as ideas and simulations are, spell delay if they do not couple with real field experiments—from nozzle sizes on up to albedo measures —which finally decide.

JB: Okay. But what are some other things that could go wrong with this sulfur dioxide scheme? I know you’re not eager to focus on the dangers, but you must be able to imagine some plausible ones: you’re an SF writer, after all. If you say you can’t think of any, I won’t believe you! And part of good design is looking for possible failure modes.

GB: Plenty can go wrong with so vast an idea. But we can learn from volcanoes, that give us useful experiments, though sloppy and noisy ones, about putting aerosols into the air. Monitoring those can teach us a lot with little expense.

We can fail to get the aerosols to avoid clumping, so they fall out too fast. Or we can somehow trigger a big shift in rainfall patterns—a special danger in a system already loaded with surplus energy, as is already displaying anomalies like the bitter winters in Europe, floods in Pakistan, drought in Darfur. Indeed, some of Alan Robock’s simulations of Arctic aerosol use show a several percent decline in monsoon rain—though that may be a plus, since flooding is the #1 cause of death and destruction during the Indian monsoon.

Mostly, it might just plain fail to work. Guessing outcomes is useless, though.  Here’s where experiment rules, not simulations. This is engineering, which learns from mistakes. Consider the early days of aviation. Having more time to develop and test a system gives more time to learn how to avoid unwanted impacts. Of course, having a system ready also increases the probability of premature deployment; life is about choices and dangers.

More important right now than developing capability, is understanding the consequences of deployment of that capability by doing field experiments. One thing we know: both science and engineering advance most quickly by using the dance of theory with experiment. Neglecting this, preferring only experiment, is a fundamental mistake.

JB: Switching gears slightly: in March last year you went to the Asilomar Conference on climate intervention technologies. I’ve read the report:

• Asilomar Scientific Organizing Committee, The Asilomar Conference Recommendations on Principles for Research into Climate Engineering Techniques, Climate Institute, Washington DC, 2010.

It seems unobjectionable and a bit bland, no doubt deliberately so, with recommendations like this:

"Public participation and consultation in research planning and oversight, assessments, and development of decision-making mechanisms and processes must be provided."

What were some interesting things that you learned there? And what’ll happen next?

GB: It was the Woodstock of the policy wonks. I found it depressing. Not much actual science got discussed, and most just fearlessly called for more research, forming of panels and committees, etc. This is how bureaucracy digests a problem, turning it quite often into fertilizer.

I’m a physicist who does both theory and experiment. I want to see work that combines those to give us real information and paths to follow. I don’t see that anywhere now. Congress might hand out money for it but after the GAO report on geoengineering last September there seems little movement.

I did see some people pushing their carbon capture companies, to widespread disbelief. The simple things we could do right now like our CROPS carbon capture proposal are neglected, while entrepreneur companies hope for a government scheme to pay for sucking CO2 from the air. That’ll be the day!—far into the crisis, I think, maybe several decades from now. I also saw fine ideas pushed aside in favor of policy wonk initiatives. It was a classic triumph of process over results. As is many areas dominated by social scientists, people seemed to be saying, "Nobody can blame us if we go through the motions.”

That Decade of Dithering is upon us now. The great danger is that tipping points may not be obvious, even as we cross them. They may present as small events that nonetheless take us over an horizon from which we can never return.

For example, the loss of Greenland ice. Once the ice sheet melts down to an altitude below that needed to maintain it, we’ve lost it. The melt lubricates the glacier base and starts a slide we cannot stop. There are proposals of how to block that—essentially, draw the water out from the base as fast as it appears—but nobody’s funding such studies.

A reasonable, ongoing climate control program might cost $100 million annually. That includes small field experiments, trials with spraying aerosols, etc. We now spend about $5 billion per year globally studying the problem, so climate control studies would be 1/50 of that.

Even now, we may already be too late for a tipping point—we still barely glimpse the horrors we could be visiting on our children and their grandchildren’s grandchildren.

JB: I think a lot of young people are eager to do something. What would be your advice, especially to future scientists and engineers? What should they do? The problems seem so huge, and most so-called "adults" are shirking their responsibilities—perhaps hoping they’ll be dead before things get too bad.

GB: One reason people are paralyzed is simple: major interests would get hurt—coal, oil, etc. The fossil fuel industry is the second largest in the world; #1 is agriculture. We have ~50 trillion dollars of infrastructure invested in it. That and inertia—we’ve made the crucial fuel of our world a Bad Thing, and prohibition never works with free people. Look at the War on Drugs, now nearing its 40th anniversary.

That’s why I think adaptation—dikes, water conservation, reflecting roofs and blacktop to cool cities and lower their heating costs, etc.— is a smart way to prepare. We should also fund research in mineral weathering as a way to lock up CO2, which not only consumes CO2 but it can also generate ocean alkalinity. The acidification of the oceans is undeniable, easily measured, and accelerating. Plus geoengineering, which is probably the only fairly cheap, quick way to damp the coming chaos for a while. A stopgap, but we’re going to need plenty of those.

JB: And finally, what about you? What are you doing these days? Science fiction? Science? A bit of both?

Both, plus. Last year I published a look at how we viewed the future in the 20th Century, The Wonderful Future We Never Had, and have a novel in progress now cowritten with Larry Niven—about a Really Big Object. Plus some short stories and journalism.

My identical twin brother Jim & I published several papers looking at SETI from the perspective of those who would pay the bills for a SETI beacon, and reached conclusions opposite from what the SETI searches of the last half century have sought. Instead of steady, narrowband signals near 1 GHz, it is orders of magnitude cheaper to radiate pulsed, broadband beacon signals nearer 10 GHz. This suggests new way to look for pulsed signals, which some are trying to find. We may have been looking for the wrong thing all along. The papers are on the arXiv:

• James Benford, Gregory Benford and Dominic Benford, Messaging with cost optimized interstellar beacons.

• Gregory Benford, James Benford and Dominic Benford, Searching for cost optimized interstellar beacons.

For math types, David Wolpert and I have shown that Newcomb’s paradox arises from confusions in the statement, so is not a paradox:

• David H. Wolpert and Gregory Benford, What does Newcomb’s paradox teach us?

JB: The next guest on this show, Eliezer Yudkowsky, has also written about Newcomb’s paradox. I should probably say what it is, just for folks who haven’t heard yet. I’ll quote Yudkowsky’s formulation, since it’s nice and snappy:

A superintelligence from another galaxy, whom we shall call Omega, comes to Earth and sets about playing a strange little game. In this game, Omega selects a human being, sets down two boxes in front of them, and flies away.

Box A is transparent and contains a thousand dollars.
Box B is opaque, and contains either a million dollars, or nothing.

You can take both boxes, or take only box B.

And the twist is that Omega has put a million dollars in box B if and only if Omega has predicted that you will take only box B.

Omega has been correct on each of 100 observed occasions so far—everyone who took both boxes has found box B empty and received only a thousand dollars; everyone who took only box B has found B containing a million dollars. (We assume that box A vanishes in a puff of smoke if you take only box B; no one else can take box A afterward.)

Before you make your choice, Omega has flown off and moved on to its next game. Box B is already empty or already full.

Omega drops two boxes on the ground in front of you and flies off.

Do you take both boxes, or only box B?

If you say you’d take both boxes, I’ll argue that’s stupid: everyone who did that so far got just a thousand dollars, while the folks who took only box B got a million!

If you say you’d take only box B, I’ll argue that’s stupid: there has got to be more money in both boxes than in just one of them!

So, this puzzle has a kind of demonic attraction. Lots of people have written about it, though personally I’m waiting until a superintelligence from another galaxy actually shows up and performs this stunt.

Hmm—I see your paper uses Bayesian networks! I’ve been starting to think about those lately.

But I know that’s not all you’ve been doing.

GB: I also started several biotech companies 5 years ago, spurred in part by the agonizing experience of watching my wife die of cancer for decades, ending in 2002. They’re genomics companies devoted to extending human longevity by upregulating genes we know confer some defenses against cardio, neurological and other diseases. Our first product just came out, StemCell100, and did well in animal and human trials.

So I’m staying busy. The world gets more interesting all the time. Compared with growing up in the farm country of Alabama, this is a fine way to live.

JB: It’s been great to hear what you’re up to. Best of luck on all these projects, and thanks for answering my questions!


Few doubt that our climate stands in a class by itself in terms of complexity. Though much is made of how wondrous our minds are, perhaps the most complex entity known is our biosphere, in which we are mere mayflies. Absent a remotely useful theory of complexity in systems, we must proceed cautiously. – Gregory Benford

77 Responses to This Week’s Finds (Week 310)

  1. John F says:

    I too have enjoyed Benford’s novels, but liked Timescape best. The only two schemes I see mentioned here are ocean dumping (aka ocean sequestration), and sulfur aerosols. Because the vast bulk of the carbon in the proposed waste is cellulosic, it aerobically decomposes on the ocean bottom about an order of magnitude faster than the proffered thousand of years. To slow it down it would have to be buried in the sediment. Moreover, it simply isn’t that much carbon.

    It turns out silicaceous aerosols have unpublicized respiratory concerns I won’t belabor here, except to caution don’t try this at home, and high altitide sulfur (dioxide etc) aerosols have very publicized high altitude chemistry problems, and of course low altitude is just acid rain. The effects of any given aerosol distribution do not need much further experimentation. The most highly used Earth atmosphere radiative transfer codes, e.g. MODTRAN,

    http://en.wikipedia.org/wiki/MODTRAN

    have adequate aerosol models. As Benford says it is the evolution of any given aerosol distribution that is not well known, but further that evolution is not known to scale properly from small experiments.

    Benford here objects to geoengineering big changes in rainfall patterns because of unspecified special dangers. What are the main points of concern for example huge ocean fountains injecting huge amounts of water vapor, droplets, and sulfates upwind of the Sahara?

    • John Baez says:

      John F wrote:

      Because the vast bulk of the carbon in the proposed waste is cellulosic, it aerobically decomposes on the ocean bottom about an order of magnitude faster than the proffered thousand of years. To slow it down it would have to be buried in the sediment. Moreover, it simply isn’t that much carbon.

      Those would be killer objections if true. So, let’s see what Benford and Metzger say in their paper!

      They consider a variety of carbon sequestration methods. They start by listing seven properties any good method should have:

      Significant removal at global scales requires that methods: (1) deal with very large quantities of carbon, (2) sequester the carbon efficiently, and (3) are repeatable over centuries.

      Atmospheric CO2 carbon is accumulating at the rate of about 4-6 Pg (Pg, petagram, 1015 g, 1 gigaton) per year. For a successful carbon removal technology to have a significant impact on that rate of increase, the technology must remove and sequester at least 0.5 Pg per year (half a “stabilization wedge” [1]) over many years, at least as long as fossil fuel carbon is released to the atmosphere. Technologies that achieve lower rates are worthwhile in that they may have a cumulative effect, but individually they will not significantly affect atmospheric CO2 levels. Their individual global impacts will probably always be uncertain, given the other yearly variations in detected CO2 levels.

      There are additional criteria for practically implementing any proposed CO2 removal method: (4) permanence: securing the carbon sequestered from the atmosphere for thousands of years, (5) no side effects that produce unacceptable environmental damage, (6) rapid and certain implementation, capable of large-scale use within years, not decades (methods demanding lengthy development, or whose success is uncertain, are less desirable than those that are sure, practical, require little research, and can be implemented soon.)

      Finally, the best method will also be (7) economical. No matter how deep our crisis gets, politics and culture will select for economy of effort. Economics will matter, especially among the developing countries.

      So, regarding your point that the CROPS method won’t sequester “that much” carbon, Benford and Metzger are not demanding that it solve the whole problem: for that we’d need to sequester 4-6 gigatonnes per year. They’ll be satisfied if it takes a significant bite out of the problem: half a gigatonne per year.

      Indeed, I think it’s very dangerous to demand that any one method get rid of more carbon than this. It seems likely that the solution to global warming will require many different actions taken together.

      They argue, in fact, that 0.6 gigatonnes of carbon can be sequestered per year by their proposed method: taking crop residues and putting them at the bottom of the ocean:

      Global large-scale agriculture produces about 2 Pg of carbon from crop residues annually. If the average fraction of above-ground crop residue that can be removed sustainably is assumed to the same as that for corn, 0.3 [3, 30], the global crop residue supply is about
      0.6 Pg C.

      (By the way, I prefer the word ‘gigatonne’ to the word ‘petagram’ or the abbreviation ‘Pg’, simply because I’m trying to talk to a large audience, and I think more people can guess what ‘gigatonne’ means. But they all mean the same thing.)

      Now, what about your other question: will the carbon stay down at the bottom of the ocean for about a thousand years, or much less time? Benford and Metzger write:

      Crop residue oceanic permanent sequestration takes advantage of two characteristics of the deep ocean: (1) minimal mixing between the deep sea waters and the upper oceanic layer in contact with the atmosphere [35, 36], and (2) the relative stability of terrestrially derived organic matter in the sediments compared to marine organic matter [37-40], due to the cold, limited oxygen availability, and apparent lack of a marine mechanism for the breakdown of lignocellulose equivalent to that of the terrestrial lignin peroxidase systems.

      Only one part per thousand of the CO2 in the deep ocean layer below 1500 m leaks into the upper layer annually, on average [36]. Combined with the slow remineralization rate in marine sediments, deep ocean separation from the atmosphere would sequester carbon for thousands of years, thus it meets criterion 4.

      So, they have at least thought about your objections and tried to meet them. What do you think?

      • John F says:

        I think that organic decay rates on top of ocean sediment are much more rapid than indicated, several dozens of years rather than several thousands. For example it is rare indeed to find exposed shipwrecks undecayed after centuries.

        I tried to find a review article about exposed shipwreck wood degradation, maybe you can have better luck, but almost all dwelled on sediment buried wood. This one by Jurgens and Blanchette

        http://forestpathology.cfans.umn.edu/pdf/Jurgensabc.pdf

        focused on a particular wreck, and cool cellular stuctures remaining after all the cellulose etc decayed long ago.

      • John F says:

        I forgot to think about how to avoid zone mixing when dumping gigatons of bales from on top.

      • John F says:

        Found one, or rather the abstract. Gjelstrup-Björdal and Nilsson, 2008, Journal of Archaeological Science, 35, 862-872. “After 3 years, wood samples above the seabed were totally decomposed”

      • John Baez says:

        John F wrote:

        I think that organic decay rates on top of ocean sediment are much more rapid than indicated, several dozens of years rather than several thousands.

        I don’t think Benford and Metzger were saying it would take thousands of years for crop residues on the ocean floor to decay. I think they were saying it takes about a thousand years for the CO2 to reach the atmosphere:

        Only one part per thousand of the CO2 in the deep ocean layer below 1500 m leaks into the upper layer annually, on average [36].

        For what it’s worth, reference [36] is:

        • T. R. S. Wilson, The deep ocean disposal of carbon dioxide, Energy Convers. Manage 33 (1992), 627–633.

        They also cite a bunch of other interesting-sounding papers.

        Greenpeace came out with a vaguely relevant report:

        • Paul Johnston, David Santillo, Ruth Stringer, Rémi Parmentier, Bill Hare and Martina Krueger, Ocean disposal/sequestration of carbon dioxide from fossil fuel production and use: an overview of rationale, techniques and implications.

        A lot of it focuses on the idea of extracting CO2 from the exhaust of coal-fired power plants and pumping it down to the ocean floor, leaving it to rest there in liquid pools. This approach seems dumb compared to the Benford-Metzger approach in at least two ways:

        • it costs more to extract CO2 from smokestacks than let plants do the work,

        and

        • liquid CO2 pools on the ocean floor sound inherently shorter-lived than bales of crop residue.

        The Greenpeace report seems designed to deep-six the whole idea of ocean-floor carbon sequestration, but it’s still worth reading.

        • John F says:

          From Strand and Benford (which when I read it a couple years ago didn’t strike me as, you know, that Benford), the essence of CROPS is “biomass,
          which would be sunk in the ocean and eventually buried by sedimentation”, so the biomass has to dodge decaying before *eventually* burying.

          And there is this whole other elephant in the ocean of vertical mixing during the falling of billions of bales per year. From the Greenpiece report, deep “dumped CO2 could reach surface waters” an order of magnitude faster than CROPS suggests, not even taking into account “Mixing is unlikely to be uniform, but may take place at localised active regions, such as” such as dump locations.

  2. Is the CROPS method really that permanent? Won’t the straw bales decompose?

    Here’s my boring routine question/criticism: What about biochar?

    I would combine the CROPS scenario with pyrolization of the crop residues, harvesting the contained energy (wood gas) and sequestering the char coal (which is essentially non decomposing). Pouring the char into the ocean would be a waste: Use it in agriculture, first putting it in CAFO cesspools etc. (thus fixating the nitrogen and balancing the C/N ratio) then put it on the fields (thus vastly improving soil).

    Forget c20th organic farming! You (hominids) need carbon negative agriculture now.

    And there’s not only crop residues. Looking at North American forests, there’s a huge problem of forest residues (yes, residues of entire forests killed by the bark beetle). Next: To sequester the residues of the Amazon forest…

    • John F says:

      Florifulgurator,
      I’ve said before I think the main atmospheric-carbon-removal benefit from char is from increased humification, which occurs in aerobic (vadose) soil. Forbes et al. (2006, “Formation, transformation and transport of black carbon (charcoal) in terrestrial and aquatic ecosystems”, Science of The Total Environment, 370, 190-206) has the rather incredible estimate “The BC pool in marine sediments is significant and is considered to comprise 12–31% of sedimentary organic carbon (SOC) in the deep ocean”.

      Certainly char in sediment would have less decomposition, and I agree it would be a waste (no humification within sedimentation), but it may be the only thousand year solution.

      • John Baez says:

        Thanks for the carbon reference, John F! The abstract but not the paper is freely available here.

        By “incredible estimate” do you mean that you don’t believe this estimate, or just that it’s surprising?

        (My wife Lisa got a degree in classics, and she had a professor who took language seriously. He would sometimes tell a student “your paper is incredible!” It would take them a minute to realize that they weren’t being complimented.)

        • John F says:

          I find it surprising, and I don’t believe it (I expect it’s off by a factor of 2 or so). But being opinions about likelihoods of numbers it’s hard to say it’s actually unbelievable, which probably requires disagreement of a full order of magnitude or more.

        • John F says:

          Important letter I didn’t read when it came out, Dickens et al., 2004, “Reburial of fossil organic carbon in marine sediments”, Nature, 427, 336-339.

          http://www.nature.com/nature/journal/v427/n6972/full/nature02299.html

          Char is typically a few percent of organic carbon in marine sediment. “Inorganic” fossil black carbon weathered from rocks makes up a significant portion of the black carbon in deep marine sediments, eventaully reaching 6.5% of TOC 200 km offshore. This petrogenic carbon heavily skews decay age estimates, and the authors conclude that age estimates of thousands of years are based on underestimation of decay rates.

        • Phil Henshaw says:

          There’s a broad caution of high value that should be raised in all these discussions of how to get more out of the earth as more and more of our interventions have unexpected emerging complications later…

          When trying to design around emerging negative environmental responses to past solutions for other things, that design problem itself is direct evidence of a changed working environment. It indicates that easy solutions without unexpected negative consequences are running out.

          It’s a way to gage the degree of exhaustion of potential intervention in a complex system you are looking for ways to intervene in. The real caution is that:

          “When increasingly risky solutions seem everywhere, the most appealing solutions are ones for which the dangerous risks are hidden from the viewpoint of the researcher…”

  3. streamfortyseven says:

    “They got a 10% chance of it happening in two centuries, assuming a business as usual scenario. But there are a lot of uncertainties in the modeling here.”

    Forget it. 10% chance of something dire happening in two centuries, and spending $100 million a year to (perhaps) prevent it? As a taxpayer, I’m not buying that, and there’s not a single member of Congress who will buy it either. The time horizons on this are ridiculous, people just don’t care about things that will for sure happen after their projected lifetime (figure at most 50 years from now for most of the people here).

    Most people in the US and developed countries are nominally some flavor of Christian, which posits existence of an eternal non-Earthly reward of some sort, or atheist, which posits oblivion. Now, people in countries where the dominant religion features a belief in reincarnation may be encouraged to take action, since they might believe that they’ll have to deal with the consequences of their ancestors’ actions on down the line.

    As for children, a child born today will be 89 years old in 2100 AD. For most of us here, that would be a grandchild, and it’s more likely that they’ll be dead by 2100 AD than alive, given resource depletion and the current rate of population expansion. The world population is forecast to be 9.1 billion by 2050 (see http://www.unfpa.org/public/datafordevelopment/statistics) and if increase is linear, about 13 billion by 2100, the great majority of that in Asia. Any oil still produced by that time, as well as any coal or natural gas, will be staying there and will be burned there. I think it’s not unreasonable to predict that not a single forest will remain unburned by that time, so that most of the world will end up looking like Haiti, with about the same standard of living.

    The real spoiler to any means of controlling climate change is the increase in population in the third world and developing countries, and concomitant fossil fuel usage (and depletion) for food production, transport, and heating/cooling. Most of these countries have religions which hold fertility in high esteem, and so birth control is not likely to happen. Western food aid will continue to boost populations in these countries far beyond their natural carrying capacities, and as a side effect, production of greenhouse gases will also increase.

    • John Baez says:

      John wrote:

      They got a 10% chance of it [a collapse of the Atlantic meridional ocean circulation] happening in two centuries, assuming a business as usual scenario. But there are a lot of uncertainties in the modeling here.

      streamfortyseven wrote:

      Forget it. 10% chance of something dire happening in two centuries, and spending $100 million a year to (perhaps) prevent it?

      I think you’re being unfair here.

      First of all, a collapse of ocean circulation in the Atlantic leading to drastic climate change is only one possible consequence of global warming. It’s far from the most likely consequence, and it’s far from the one that’s likely to happen first. So we cannot fairly evaluate the benefits of fighting global warming based primarily on this particular calculation!

      Second of all, it’s very clear from Keller and Urban’s paper—or Nathan Urban’s interview here—that their calculation was just a ‘test run’ of some ideas that need to be explored in more depth. It’s not supposed to be a basis for policy decisions. It’s supposed to incite people to do better calculations of a similar sort.

      The real spoiler to any means of controlling climate change is the increase in population in the third world and developing countries, and concomitant fossil fuel usage (and depletion) for food production, transport, and heating/cooling.

      People argue a lot about precisely how much population increase contributes to the problem of global warming. Clearly it’s a big part of the problem! But exactly how much? Let me just contribute a few facts:

      From 1980 to 2007 the world-wide usage of power went from 10 to 16 terawatts. The population went from 4.4 billion to 6.6 billion. So, the power usage per capita must have gone from 2.2 kilowatts to 2.4 kilowatts.

      So:

      • The power per capita went up about 10%.

      • The population went up about 50%.

      • The total power usage went up 60%.

      So, during this time period we’d have to say population increase was the major driver of increased power consumption (and thus, to a large extent, carbon emissions).

      But in the years to come, increased per capita power consumption may become more important — at least, in a scenario where there’s not a worldwide economic collapse.

      The world population is forecast to be 9.1 billion by 2050 (see http://www.unfpa.org/public/datafordevelopment/statistics) and if increase is linear, about 13 billion by 2100, the great majority of that in Asia.

      I don’t think most people expect linear population increase after 2050. The best estimate from the United Nations 2004 report is the middle curve here, the orange one:

      Here’s what the report says (emphasis mine):

      Long-range population projections are reported to 2300, covering twice as long a period as ever covered in previous United Nations projections. These projections are not done by major area and for selected large countries (China and India), as was the previous practice, but for all countries of the world, providing greater detail. In these projections, world population peaks at 9.22 billion in 2075. Population therefore grows slightly beyond the level of 8.92 billion projected for 2050 in the 2002 Revision, on which these projections are based. However, after reaching its maximum, world population declines slightly and then resumes increasing, slowly, to reach a level of 8.97 billion by 2300, not much different from the projected 2050 figure.

      [...]

      Europe and Africa will be particularly out of phase. Europe will hit its low point in growth in 2050, Africa not till 80 years later, after all other major areas. From 2000 to 2100, Europe’s share of world population is cut in half, 12.0 to 5.9 per cent, while Africa’s almost doubles, from 13.1 to 24.9 per cent. While shares of world population for major areas will rise and fall over the following two centuries, the distribution by 2300 will resemble that in 2100. Smaller regions within continents exhibit divergent patterns. For instance:

      • Three African regions — Eastern Africa, Middle Africa, and Western Africa — will grow unusually fast in comparison to every other region through 2100, even though total fertility will be close to replacement by 2050.

      • Southern Africa is seeing a decline in life expectancy to a lower level than anywhere else, but life expectancy will rebound, rise quite rapidly, and overtake other African regions.

      • Asian regions will grow fastest to the west, slowest to the east, but in every case with growth rates, at least up to 2100, below Eastern, Middle and Western Africa. By 2100, Asia, instead of being four-and-a half times as populous as Africa, will be only 2.2 times as populous.

      • Latin America and the Caribbean is the most homogenous major area, with most of its regions following relatively parallel fertility and life expectancy paths.

      Northern America is unusual as the only region that will not experience negative growth, mainly due to projected migration up to 2050. (No migration is incorporated in projections beyond that date.)

      • Europe, like Asia, will experience higher growth to the west, lower growth to the east. Eastern Europe stands out with low life expectancy, and even in the long run does not catch up with other regions.

      I’m pretty sure none of these estimates take into account possible disruptions from peak oil, global warming, economic crises or warfare such events might provoke, and so on.

      • streamfortyseven says:

        Here’s a guy who seems to be expressing the same sort of skepticism I was, but putting it in mathematical terms – and finding a possible solution:

        “The use of a constant discount rate to study long-lived environmental problems such as global warming has two disadvantages: the prescribed policy is sensitive to the discount rate, and with moderate discount rates, large future damages have almost no effect on current decisions. Time-consistent quasi-hyperbolic discounting alleviates both of these modeling problems, and is a plausible description of how people think about the future.”

        from

        • Larry Karp, Global Warming and Hyperbolic Discounting University of California, Berkeley and Giannini Foundation.

        As to the UN projections after 2075 or so, do they say *why* they expect population to essentially stay constant for the next 125 years?

        • Nathan Urban says:

          streamfortyseven,

          Here’s a guy who seems to be expressing the same sort of skepticism I was, but putting it in mathematical terms – and finding a possible solution:

          You may be conflating “is” and “ought”.

          It’s certainly true that people don’t care as much about the future as the present. That’s one reason why economists use a discount rate. (It’s not the only reason; supposedly, even if you care equally about the future and the present, you’d still prefer money now to money later, so you can invest it.)

          On the other hand, you seem to imply that people shouldn’t be willing to pay to mitigate the risk of low-probability, high-impact events in the more distant future. The empirical observation about how people feel about money is independent of the moral question of whether people should care about the future (and how much).

          Karp’s paper doesn’t “solve” the problem of people not caring about the future. He merely reviews how changing the discounting assumption, in a way previously discussed in the economic literature, alters how much mathematical value is assigned to future climatic events. (He also has a followup paper on “catastrophic events” of the type we’re discussing.)

          That is, if you don’t want to assume that humans are “callous toward the far-distant future”, change the assumption about how much humans value the future! (Rather tautological, but the details are in how you choose to do this.)

          However, this neither addresses whether humans actually value the future environment using hyperbolic discounting (assorted psychological experiments notwithstanding), nor whether they should do so (it presumes they should but gives no specific moral arguments for that position).

          A good review of discounting focusing on the is-ought question or (“descriptive” vs. “prescriptive” or “normative” economics) is Quiggin (2008). I mentioned this paper in Week 303.

          By the way, I find your generalizations about how Judeo-Christians or atheists don’t care about anything that happens on Earth after they’re dead to be bizarre.

          Also, as John argues, I don’t think that population increase in the developing world is the real problem. It’s the increase in fossil energy demand if the developing world aspires to attain inefficient and carbon-intensive U.S. consumption patterns. I mentioned this previously when you brought up population growth.

      • John Baez says:

        Streamfortyseven:

        As to the UN projections after 2075 or so, do they say *why* they expect population to essentially stay constant for the next 125 years?

        Fertility rates worldwide are plummeting, while lifespans are increasing. In 2007, the only European country with a fertility rate above the replacement rate was Iceland, with 2.07 children per woman. The next highest were France at 1.98 and Norway at 1.9. In eastern Europe countries the average is just 1.3!

        More significantly, fertility is currently dropping fast in Asia, Africa, and Latin America! Check out this graph from page 6 of the 2004 report. Click to enlarge:

        The U.N. report predicts that fertility is heading down towards 1.87 worldwide by 2075. For some reason they predict that it will then rise again to replacement levels by 2155… but I don’t trust predictions so far in the future.

        Personally I would be very happy to see population stabilize at levels far below the current one.

        I don’t know what people expect to happen if a global economic collapse were to stop the ‘rising standard of living’ that typically makes fertility rates go below 2.

        • streamfortyseven says:

          The sort of global economic collapse (due probably in large part to peak energy and concomitant decline) I think we’re headed for will probably result in an increase in infant/child mortality due to malnutrition/starvation and poor pre-natal nutrition, thus the fertility rates in countries far beyond their carrying capacity would probably go below 1.00 … think Sahel: http://ec.europa.eu/echo/aid/sub_saharian/sahel_en.htm and http://www.gmfc.org/es/noticias/world-news-on-child-rights/871-one-in-four-children-in-the-sahel-region-of-chad-suffer-malnutrition

          I believe Mobus’ answer, the “politically incorrect” one he doesn’t want to state outright, is hinted at in:

          the other kind of hope, the one that dominates my thinking now, is that humanity will exercise some sensibility, some good judgment, and recognize the need to bow out gracefully. The actions taken thereafter might just increase the odds for a humanity in the future. Not unlike the man who seeks redemption while dying, perhaps humanity will exercise wisdom as a last act. There is a way to make this work.

          This looks like mass suicide to me, somewhat like the Depopulationists in

          • Whitley Streiber, Nature’s End: The Consequences of the Twentieth Century.

          where a worldwide movement is pushing for the voluntary suicide of 1/3 of the world population. Somehow I don’t think the Pope will go for it…

        • Phil Henshaw says:

          John, I think the important reason for why the UN projections are what they are is shown in your graphs. They’re projecting the past as the future.

          New factors, though, tend to enter the picture “a bit off the page”. Those graphs all depend entirely on continuing to deplete the earth’s resources at ever accelerating rates. That is what growth is based on, and what we have been doing during all of the history if economic development. It’s a short term process with as relatively abrupt dead end.

          Where it naturally ends is in a transition to one or another population limiting process. The choices depend on all the hidden dynamics as well as whether people respond realistically and change their problem definition while they have the time and resources to do so…

          That’s part of why learning is involved in steering natural systems, they keep doing new stuff for reasons you wouldn’t have seen till you got to them… I makes for a need to pay attention to how things out of one’s control are behaving.

        • John Baez says:

          Phil wrote:

          Those graphs all depend entirely on continuing to deplete the earth’s resources at ever accelerating rates. That is what growth is based on, and what we have been doing during all of the history if economic development. It’s a short term process with as relatively abrupt dead end.

          Yeah, I know. That’s why I said:

          I’m pretty sure none of these estimates take into account possible disruptions from peak oil, global warming, economic crises or warfare such events might provoke, and so on.

          The UN population projections will be reasonably accurate until something big comes along that they don’t take into account. Their projections march blithely to 2300 but almost surely something big will come along much sooner. I don’t know why they bothered to extrapolate existing trends to such a ridiculous extent. But I think they can be useful for the next 5-10 years.

          Most of the big things I can imagine would push populations further down rather than back up, but that could perhaps just be a shortage of imagination on my part.

        • Phil Henshaw says:

          John, Yes, but in addition to the OECD economic assumptions ignoring the predictable high costs of emerging environmental impacts like replacing depleting resources, their financial model lack even a cost category for emerging hidden complications such as all the ones we’ve been running into! It’s the rapidly growing hidden liabilities of intervening in the earth’s systems at ever increasing scale, that are the problem we’re dealing with. That won’t be solved by ever increasing the scale of our interventions and their hidden liabilities!

          That’s what I think is quite odd that people are not picking up on, a real cognitive gap. I think the blind spot is our ancient assumption that improving productivity will solve any problem. So we can’t define the problem of our having become TOO productive. The result is that we fall prey to attempting valiant but unexpectedly risky solutions with ever bigger hidden liabilities instead.

          Peak oil is just one of dozens of many new emerging “blowbacks” of our overinvestment in controlling a now fragile planet. Those include the societal conflicts coming from the mounting population/food pandemic, and the quite irresolvable sovereign debt crisis. How our mistaken “productivity” model causes them is clearly visible in how we manage money for past savings to have forever multiplying productivity in the future.

          The way I first understood it was in terms of that perceptual trap I mentioned yesterday. If you are looking to make increasing investments in an environment of diminishing returns, what you’ll be attracted to are investing more and more in things with hidden liabilities. You see the implication of that for finance, right? What that natural effect of growing investment in an unresponsive environment is a natural behavior exactly like what we saw in the world financial bubble and collapse.

          So it seems to mean that if we were telling the financial system to produce ever growing returns, when the earth is producing ever greater hidden liabilities instead, then the cause of the wall street crash was the traders doing exactly what we asked them to do. Then the hidden liabilities everyone talks about, the greed and malfeasance and ‘bad luck’, that “somehow” turned out to permeate the system top to bottom, were then a direct natural environmental impact on the financial system… that fooled everyone. Do you see that?

        • John Baez says:

          Phil wrote:

          It’s the rapidly growing hidden liabilities of intervening in the earth’s systems at ever increasing scale, that are the problem we’re dealing with. That won’t be solved by ever increasing the scale of our interventions and their hidden liabilities!

          I agree that we may be reaching a situation where ever more desperate measures may only postpone a global economic/ecological collapse for shorter and shorter time periods.

          I think a lot of people have this feeling now. Artists often express feelings more clearly than scholars, so here’s what Thom Yorke of Radiohead had to say about their excellent song Like Spinning Plates:

          I focus on the most imminent ecological issues. You know, there are so many scenarios on the horizon at the moment that will result in mass suffering. For the most part in the West we worship a certain type of economics, which is like worshipping a false god. It’s a theory about economics which will collapse, and the sooner people realize that, the quicker they will be able to understand how we should be engaging with the world around us. To me, it’s like spinning plates: I’m not sure how long we can keep this trick going.

          On the other hand, it’s possible that geoengineering together with a wide range of measures aimed at lessening our negative impacts on the biosphere are what we need now.

          These are some of the issues I think people should be discussing here…

          So it seems to mean that if we were telling the financial system to produce ever growing returns, when the earth is producing ever greater hidden liabilities instead, then the cause of the wall street crash was the traders doing exactly what we asked them to do. Then the hidden liabilities everyone talks about, the greed and malfeasance and ‘bad luck’, that “somehow” turned out to permeate the system top to bottom, were then a direct natural environmental impact on the financial system… that fooled everyone. Do you see that?

          I’m not sure a “direct environmental impact” is the best way of describing the cause of the Wall Street crash, but I agree that the financial system was trying to pretend it could keep up a growth rate that it could not, in fact, keep up.

          I suppose that if the Earth had ten times as many easily exploitable natural resources as it actually does, the economic system might have kept up its promised growth rate for a while—until it hit the wall.

          And yes, I think we may be hitting the wall roughly around now. I’d love to be wrong on this.

        • Phil Henshaw says:

          Yes, the simple place to start is with understanding that, for whatever reason, wall street was trying to sustain a high growth rate in an environment that wouldn’t sustain it.

          That becomes the center piece of my systems research method, noting that growth is a system and there would naturally be some point of reversing potential for it in its environment, that it would necessarily cross as it progresses. That gives you a pair of leading questions, when will that occur and how do you respond.

          Currently the business community seems to typically a) not notice when it occurs and b) respond by being obstinate in believing we just have not tried enough wild schemes to get unsustainable growth to continue. The other response, all but completely unthinkable in our culture, is at that point of diminishing returns where limitless growth becomes dangerous, to switch the object of investment from exploiting to nourishing your environment.

          Keynes was actually the first to recognize that option, and got pilloried for it, of course. I’ve written various things on the subject. fyi search with “site:synapse9.com keynes”

        • John, geoengineering, especially as regards aerosols of silicates, or aluminum/alumina particles, or SO2, or H2S (which is poisonous on a parts per million scale – see http://en.wikipedia.org/wiki/Hydrogen_sulfide) may well have unintended consequences.

          I’ve already stated here that ultrafine particulate matter presents a danger to cardiovascular and pulmonary health, and is directly connected to increased mortality amongst infants, elderly, and those with COPD and asthma, and I think I’ve listed a number of studies below which talk about these things.

          Dr Benford states in a comment below as regards the possibility of these unintended consequences having a significant effect on human populations that “[t]he increased risk is trivial, and in the least populated region of the world. You’re citing dust densities orders of magnitude higher.”

          If high winds can take ultrafine particulates three thousand miles from their origination in China, clear across the Pacific Ocean to California, where they make a detectable contribution to air pollution (http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=876180), then it doesn’t matter if the ultrafine particulates used in geoengineering efforts are generated or initially dispersed in “the least populated region of the world” they will travel thousands of miles to other regions. Indeed, some of the radioactive fallout from the Chernobyl disaster made it all the way to the US – across Russia and the Arctic and Pacific Oceans (http://users.owt.com/smsrpm/Chernobyl/glbrad.html), so there are data which show this sort of dispersal can and does occur.

          From the graphics shown as to the dispersion and rainout of the Chernobyl fallout, it’s possible to have “hot spots” where the concentrations of ultrafine particulates are not trivial – and the same goes for H2S and SO2.

          On top of which, to disperse these particles it takes high-flying aircraft and the expenditure of *lots* of jet fuel. There’s been little said about how to get the particles up in the atmosphere and what quantities of particles are needed – if it’s going to be millions of tons, then that’s a lot of jet fuel, and it will be a continuing effort since the particles are not persistent past a couple of months and thus require periodic replenishment.

        • John Baez says:

          streamfortyseven wrote:

          John, geoengineering, especially as regards aerosols of silicates, or aluminum/alumina particles, or SO2, or H2S (which is poisonous on a parts per million scale – see
          http://en.wikipedia.org/wiki/Hydrogen_sulfide) may well have unintended consequences.

          Of course! I would even be so bold as to say it will have unintended consequences. Almost everything does. For example, if we try to play it safe by not using geoengineering, that will also have unintended consequences.

          So the possibility or even the certainty of our actions having unintended consequences can never by itself be a sufficient reason for not doing something.

          We always need to dig in deeper and evaluate the possible risks of doing something and compare them to the possible risks of not doing it.

          All this is a bit obvious, and you must know it already, so forgive me for the mini-lecture. I just had to get it off my chest.

          Now, on to the specifics!

          You raise some interesting questions that deserve comment from Benford (or me, if I get around to looking up some information). Note that Benford wants to test the results of putting hydrogen sulfide or sulfur dioxide into the troposphere over the Arctic, not diatomaceous earth. So, for now, I don’t think it’s worth spending a whole lot of time discussing the effects of silica dust. If so, here are some of my top questions:

          What are the amounts of SO2 or H2S that might be needed to cool the Arctic?

          Benford said “Turns out the pollutant issue is minor, since it would be only a percent or so of the SO2 already in the Arctic troposphere.” But what calculation gives this figure?

          How many jet flights would be needed per year to put that much stuff up there? What scale of operation are we talking about here?

          I have little sense of the order of magnitude involved! Benford said “Cooling the Arctic back to, say, the 1950 summer temperature range would cost maybe $300 million/year”. But what calculation gives this figure?

          You wrote:

          On top of which, to disperse these particles it takes high-flying aircraft and the expenditure of lots of jet fuel.

          You can work out how much jet fuel $300 million would buy to put an upper bound on how much jet fuel is needed, at least if Benford’s figure is correct. In 2005, total Jet A-1 fuel consumption represented 55 billion US Gallons or 208 billion litres. $300 million of jet fuel is roughly 1% of that. I wouldn’t call that a lot of jet fuel. And apparently aviation consumes only 2% of all fossil fuels burnt.

          Of course, putting enough SO2 into the atmosphere to cool the whole world is a much larger operation. But presumably nobody is going to be dumb enough to try that before trying just the Arctic.

          (And presumably nobody is going to be dumb enough to try that before trying the small-scale experiments Benford is proposing. It’s important, when contemplating these scary things, to remember that we have a number of points where we can say “whoops – it’s not working!” and quit. And the more points like this there are, the better. It would be the height of folly to dive into geoengineering without having lots of these “call it quits” points worked out.)

    • John Baez says:

      Thanks for the gloomy population links, streamfortyseven! I agree that this stuff is incredibly important and insufficiently discussed.

      If you haven’t already, you should look at this:

      • George Mobus, Past the point of no return, Question Everything, 17 February 2011.

      It’s a fascinating post, but annoying in three ways. First, the scary graph showing a population crash has no labels on its horizontal or vertical axis. Second, he doesn’t describe the calculation that gave this graph, though he alludes to a ‘computer program’. Third, he refuses to state his solution to the population problem, saying:

      I believe there is a solution to this problem. And I believe it involves human choices and intervention in the evolutionary process that brought us into existence.

      This section is not what I originally wrote re: what is a feasible solution. My readers will guess what might have been in this section. I sent an early draft to a number of people in the no- or negative-growth community, people who fully get that we have a serious problem. But a large number of those people were extremely uncomfortable with my feasible solution! Most granted that my arguments are basically sound regarding the fate of the human species if a solution cannot be found. But few were willing to accept the conclusions. My solution, to the modified problem statement, includes a maximally coercive action that is politically unacceptable (or at least politically incorrect!). The need, remember, is to find a way to reduce the population at a rate that will exceed the rate of decline of the carrying capacity. Most people in the ‘population reduction’ movement are queasy over what that will take (look carefully at the graph above and derive your own inferences).

      I think I know what will work. It doesn’t involve overtly killing anyone. It does seek to minimize pain and suffering. But it baldly admits to a stark reality. I may be alone in a willingness to face that reality. I’m not clear as to why that is the case. But I have no wish to offend the masses. That won’t help anyone. So let me just say that the feasible solution is only for the least faint of heart. Of course, if I’m the only one to accept this reality, it won’t matter. The worst will come to pass.

      • streamfortyseven says:

        I think his computer program is a work in progress, and you might be able to get more details here: http://xmile.pbworks.com/w/page/8402924/Relevant-projects-and-initiatives – especially http://faculty.washington.edu/gmobus/SystemsScience/DynSysMod-JenniferLeafFinalPaper.pdf

        “DynSysMod is being developed primarily to allow those interested in energy systems to test various aspects of, say, an alternative energy system such as solar photovoltaics or wind. I began this project in response to the difficulties I encountered in modelling what I call the Energy Systems Sustainability Criterion. This criterion is relatively simple to understand but fiendishly difficult to get a hold of in practice. It says that any energy conversion capital equipment (such as solar panels or wind turbines) must, in the long run, produce enough excess energy above that consumed in the economy, to maintain and replace itself when its useful life is over. At first glance this might seem like a simple thing to verify, but it has second and higher order aspects, such as there must be enough energy to account for the fraction of energy used to maintain and build the manufacturing plant where the capital equipment is produced (as well as cover other work-costs). A modelling language that breaks out the explicit flows and reservoirs of energy, as well as captures the first and second laws of thermodynamics, should be very helpful in determining how energy flows through such a complex macro-system.” (from http://faculty.washington.edu/gmobus/research.html)

        Here’s Mobus’ page on his work with Charles Hall, still not complete as of January 2011: http://questioneverything.typepad.com/question_everything/2009/12/economic-dynamics-and-the-real-danger.html and it’s a little bit more informative about where he’s basing his predictions but not much.

      • streamfortyseven says:

        Mobus is being slightly disingenuous when he talks about not “overtly killing anyone”, because he has stated in the past, that “the other kind of hope, the one that dominates my thinking now, is that humanity will exercise some sensibility, some good judgment, and recognize the need to bow out gracefully. The actions taken thereafter might just increase the odds for a humanity in the future.” This is about voluntary suicide (or perhaps Jonestown-style “voluntary” suicide) as in “Nature’s End”, the book mentioned above. He’s a bit of a eugenicist here, he prefers to sacrifice the less intelligent and preserve the more intelligent – in his model, getting a low score on an IQ test might have lethal consequences…

        • John Baez says:

          Hmm. Since Mobus had said “My solution, to the modified problem statement, includes a maximally coercive action that is politically unacceptable”, I had guessed he was talking about mass sterilization or some other form of preventing childbirth.

          If his plan to save the world for “a future humanity” involved voluntary mass suicide, I don’t think this plan is realistic enough to bother thinking about. I also don’t think it fits well with any “eugenic” tendencies he might have (does he really???), since I suspect someone needs to have a fairly high IQ to be stupid enough to voluntarily commit suicide for general good. It would also be a great way to weed out any genetic tendencies toward altruism.

        • streamfortyseven says:

          Yes, I think Mobus has eugenic tendencies: from http://questioneverything.typepad.com/question_everything/2009/11/index.html
          and from one of Mobus’ comments on his article at http://questioneverything.typepad.com/question_everything/2010/03/sapience-intelligence-and-creativity-delineated.html: “I do think the bottleneck is upon us. If only the highly sapient beings on the planet were fertile it would certainly make matters simpler. But I suspect that should the forces of selection work as I think they might (not, incidentally unlike what happened each previous time there was major climate shifts) then higher sapience will have selective advantage and in the long run, Homo will achieve a yet more capable fitness level. We will no longer be obsessed with infinite growth, but will be content with the steady-state that at lower energy throughput is nevertheless sustainable.”

          It’s not humans doing genocide to other humans, it’s some unspecified force in nature creating an evolutionary bottleneck in which only “eusapient” humans survive. Functionally it’s the same as eugenics, the agent is “nature” instead of human intervention.

        • Phil Henshaw says:

          Steamfourtyseven… I always wonder about communities of intellectuals that each get one thing very very right, but don’t get them to connect have the whole picture turn out wrong as a result. Why does that happen anyway? It seems so common. Is it maybe like the six blind men and the elephant, that we don’t pay attention discussing any one subject in common…?

          I guess I’m questioning the use of George’s term “sapience” as if we knew what that was.

          There are so many remarkably well documented gaping holes in the economic model and sustainability concepts that most of the world hold as gospel it’s really almost more fascinating than frightening. To me it constitutes that “pattern that is out of place” begging for attention and saying “pay dirt” for the curious mind.

          One of several I use to play with the environmentalists these days is the curious fact that all the climate mitigation plans are predicated on continuing the one process that is most certain to continually multiply CO2. That’s compound growth in productivity in using natural resources to make money, of course. There’s no evidence of “decoupling” in the physical world, but in our minds it’s apparently rather easy! :-)

          It doesn’t take more than 10 minutes looking at the data to see that that is a mistake… but it seems to be taking me 10 years to get any of them to even acknowledge that when the survival of modern civilization seem possibly at risk it OK to ask such questions. What do you think of that evident disconnect?

          I think the human mind has dozens of features, and human culture hundreds of them, set up exclusively for our being small frightened creatures in an enormous threatening world. Now that the tables are turned we just don’t seem to think straight…

        • Web Hub Tel says:

          George Mobus has also been posting at http://TheOilDrum.com. I have commented before that he should concentrate on getting his energy flow arguments correct (using hybrid bond graphs maybe?) and leave the philosophizing for later. So far I haven’t seen much verification or even elaboration of his models. Building a complicated system dynamics graph of energy flows is much more tenuous than working out a predator/prey system — neglecting the stochastic aspects has got to be a great concern.

        • John F says:

          I think for Mobus the only feasible opposite of “overtly killing” is covertly. Hence the only feasible “other kind of hope” is the hope that those being killed won’t fight.

        • Phil, I think you’ve got something there – of course, going from a growth economy based on extraction of finite and non-renewable natural resources to a steady-state economy based on production of renewable natural resources (such as hemp, whose oil and fiber can be used as feedstocks for some many products we now get from crude oil), we’ve got to convince people who have a legal duty to ensure increasing profits to shareholders to stop doing so. Without a revolution in corporate law and regulation, that will be impossible, not to speak of the effect on those who depend on equity and bond markets for their income, and who will oppose the destruction of the means by which they get their money and power by damned near any means necessary, up to and including war – as we’ve seen in the ongoing resource wars in Iraq and Afghanistan.

        • Phil Henshaw says:

          Steamfourtyseven, Yes, you’ve identified the main cognitive barrier for using money in a sustainable way, that it’s “unthinkable”.

          However… not having explored the option for that reason has caused us to be unaware of the risks or the options for doing so. It is actually the far more profitable approach, to switch from exploiting your environment till it collapses and use your investment funds to steer you away from the emerging resource wars and have resources to use for nourishing your environment instead.

          Still, the odd reasons that humans don’t seem to recognize absolute physical necessity as something worth checking out, what we seem to be waiting for is some “moment of collective genius” to allow people to even poke around in the problems presented, and sort through the better and worse options for how to proceed. I’m joking a bit there, of course, but it does seem inexplicable that we act like the world environment is our own theory, and so there’s nothing to check out, or something.

          At least I’m beginning to get little trickles of interest in the starting point for the subject that Keynes provided. What he discovered is the certainty that when the physical processes of the economy stop expanding as fast then total financial savings will stop growing either by creditors spending them or losing them… So for creditors to choose to divest as much as they earn, in total, is a capital and profit preservation scheme, needed for the case when investors literally need to “give it away or lose it”. ;-)

      • John F says:

        Since we’re discussing geoengineering solutions to climate problems, and since I for one don’t want to sacrifice humans to someone’s poorly parameterized daydreams of pre-coal Gaia, perhaps we should redefine the geoengineering goals. How about instead using geoengineering to mitigate effects of climate problems on human populations?

        • Phil Henshaw says:

          What about instead of maximizing the burdens that we know need to be limited we maintain a safe distance from the hazards we don’t understand?

          That standard is actually the one used in lots of engineering practices already, isn’t it? It think a special problem comes comes in when you are a) working with money, and b)define the system you are interacting with using your own model… That’s the economists’s approach it seems anyway, but not a truthful engineering approach I don’t think.

  4. streamfortyseven says:

    This trend doesn’t help much in general, either: http://www.crypto.com/blog/copywrongs/

  5. Gregory Benford says:

    Most of these comments are quite off subject, so I’ll just reply to John F.

    The Metzger papers and the Strand one deal with dwell times at the ocean bottom. The thermocline is the real boundary, and plenty of work shows the return time to the atmosphere is ~1000 years.

    “Moreover, it simply isn’t that much carbon.”

    The papers give numbers, worked out with efficiencies, too.

    “It turns out silicaceous aerosols have unpublicized respiratory concerns I won’t belabor here…”

    The aerosols are less than 1% of those already in the Arctic troposphere (especially for SO2). The “very publicized high altitude chemistry problems” are mostly conjectural, though the Pinatubo eruption gave us qualitative data. In the Arctic, where the stratosphere is low, the reactions are muted and ozone not at real risk, since most O3 is far above the aerosol levels. And the aerosols come down in rain and snow, and the SO2 contributes very little to acid rain.

    “The effects of any given aerosol distribution do not need much further experimentation. The most highly used Earth atmosphere radiative transfer codes, e.g. MODTRAN…”

    These are adequate codes, but the details needed for a geoengineering experiment are not in them. One of the worst aspects of studying climate through codes is the paucity of any experiments, natural or artificial, that actually test the models.

    “What are the main points of concern for example huge ocean fountains injecting huge amounts of water vapor, droplets, and sulfates upwind of the Sahara?”

    I don’t know what this refers to, but getting excited about the predicted changes in monsoon rainfall ~5% is taking these models further than they can go. The annual variation in monsoon rainfall is larger than this, and so are the year to year predictions. Flooding is the major source of monsoon damage (see Pakistan last year). Decreasing it may well be a positive side effect, if it is there at all.

    All this discussion of future populations reflects an aspect of climate change I’ve noted everywhere: love of abstractions. So at Asilomar and here many talk of events a century from now, or panels and “governance” issues. Nobody asks what we can do now. In a decade or two, we will wonder why.

    • John F says:

      I appreciate your careful attention to numbers, eye for detail, and willingness to consider these few points of debate. I’m sure we agree that huge engineering efforts should be commenced.

      1. “The papers give numbers”. But they aren’t all realistic. For example, that corn residue making up fully half of the US CROPS contribution. That residue is not currently collected, actually is utilized in place, and you haven’t made the case that even a large fraction is likely to be collected, or how to collect. That’s not yet considering the economics, which is often to me almost as interesting as cutting the lawn with scissors. Cutting to the chase: if you’re paying to transport perfectly good corn stalks offshore and dumping them, why not ocean dump waste that otherwise would go to landfills?

      2. “adequate codes, but the details needed .. are not in them”. Even 20 years ago, Pinatubo data provided *validation* of the already-included moderate volcano model. In a more recent implementation, Pinatubo is a drop down menu item you can add at will. The validity of the scaling of vertical mixing parameters is always a concern, but a concern that wouldn’t be addressed by small experiments anyway. The evolution of aerosol size distributions is about the only other fudge factor I can think of, and is entirely empirical. Are there others that further small experiments would help understand?

      3. “I don’t know what this refers to”. Although mostly known in climate contexts as the “cloud whitening” alternative to stratospheric aerosols,

      http://en.wikipedia.org/wiki/Cloud_reflectivity_modification

      I suggest that the locally greatly enhanced evaporation and rainfall may provide greater benefits than just clouds. Then too, implementations of low altitude spraying of seawater are far (100%?) less likely to be obtruded upon by weaponization concerns of particulate aerosols.

    • streamfortyseven says:

      Dr. Benford has made a good argument for China continuing to use coal for power generation, as those power plants spew huge amounts of <2.5 micron particulate matter into the atmosphere, where it persists for weeks or months before being rained out. Ultrafine particulates from Chinese sources have been found in California, more than 3000 miles away from the source.

      As for geoengineering, there is apparently serious study going on with respect to particles of aluminum coated with alumina, to raise the albedo of the atmosphere sufficiently to reduce incoming IR and thus heating of the atmosphere: see http://ieet.org/index.php/IEET/more/maynard20100917 and http://www.pnas.org/content/107/38/16428 and http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Link&db=pubmed&dbFrom=PubMed&from_uid=20823254

      • Nathan Urban says:

        Even if you accept the need for climate geoengineering, it does not follow that, from a climate / health / environmental impacts perspective, the best way to do this is through continued use of dirty coal. (Consider, for example: tropospheric vs. stratospheric injection, radiative forcing of SO2 aerosols vs. black carbon, health impacts of particulate matter concentrated near point sources, and of course the greenhouse effect.)

    • streamfortyseven says:

      Fine (<2.5 micron) and ultrafine particulate matter, which makes up the aerosols of which Dr Benford speaks, whether silicaceous or not, has a well-known effect on increased mortality due to COPD and cardiovascular events, as well as in the increase in childhood asthma:
      http://www.hsph.harvard.edu/epacenter/pubs.html and http://enhs.umn.edu/current/5103/particles/effects.html

  6. Web Hub Tel says:

    John, You might also want to interview Robert Metzger. My old boss graduated with him and said he was a very smart and interesting character. Another one of those researchers turned SciFi authors.

  7. Gregory Benford says:

    Some comments:

    streamfortyseven:
    The increased risk is trivial, and in the least populated region of the world. You’re citing dust densities orders of magnitude higher.

    John F:
    Dept of Ag estimates maybe 1/3 of crop residues should stay on the ground, mostly to prevent erosion. This is well studied, though some still think all of it should stay, though we do know that it has little nutrient value–that’s been engineered to go into corn kernels, etc. In Strand & Benford, all the efficients get spelled out, and objections answered.

    “The evolution of aerosol size distributions is about the only other fudge factor I can think of, and is entirely empirical. Are there others that further small experiments would help understand?”

    Plenty, mostly about behavior on scales less than 1000 km. There’s a whole research agenda to be worked out, especially since the Arctic is such an atypical place. If these climate models are so great, why didn’t they predict the Pakistani floods? You can’t use Pinatubo as a perturbation example; it was a huge effect worldwide, not fading away for over a year. The Arctic experiments will last maybe 4 months—another reason to do them first. Climate models are notoriously lousy at small scales ~1000 km, just where Arctic experiments begin.

    The Latham-Salter “cloud whitening” method needs testing, but there’s no money and nobody knows if it even works. Aerosols we do know lots about, as you say.

    Again, lack of real research in these areas is the surest sign that few take this seriously now. Wait a decade, when the droughts are severe, food prices are high, and the mass migrations begin. Actually, they’re already here.

  8. Alexander Kruel says:

    I already replied on LessWrong but thought I’d post here as well. Maybe Mr. Benford would be so kind and answer as well:

    I would like to ask you to write a blog post reviewing the arguments against mitigating climate change and in favor of contributing to a charity concerned with risks from artificial general intelligence and explain why you reject them, that you don’t understand them or accept the arguments and start working to mitigate risks from AI. It would be valuable to have someone like you, who is not deeply involved with the SIAI (Singularity Institute) or LessWrong.com, to write a critique on their arguments and objectives. I myself don’t have the education (yet) to do so and welcome any reassurance that would help me to take action, one way or the other.

    If you don’t have the time to write a blog post, maybe you, or Gregory Benford, can answer just the following question. If someone was going to donate $100k and asked you to pick the charity, would you choose the SIAI? A ‘Yes/No’ answer would be welcome if you are too busy, a short explanation if you’ve the time.

    Thank you!

    • John Baez says:

      Alexander wrote:

      I would like to ask you to write a blog post reviewing the arguments against mitigating climate change and in favor of contributing to a charity concerned with risks from artificial general intelligence and explain why you reject them, that you don’t understand them or accept the arguments and start working to mitigate risks from AI. It would be valuable to have someone like you, who is not deeply involved with the SIAI (Singularity Institute) or LessWrong.com, to write a critique on their arguments and objectives.

      I may try to do this after my interview series with Yudkowsky comes out. In case you’re wondering why I haven’t done this sooner: decisions like this require weighing lots of subtle issues. I often don’t feel extremely confident I’m doing this correctly, so I don’t feel it’s worth spending a lot of energy explaining my decisions or (especially!) convincing other people that I’m right. I prefer to use a lot of energy telling people about things that I do feel confident of. So, I try to spend a lot more time talking about facts I’ve learned rather than opinions I hold.

      This decision, too, could be mistaken. For one thing, it somewhat reduces the chance that my mistaken opinions will get corrected. But this effect is not as significant as you might think. I find that even when I don’t go out of my way to express my opinions, there’s no shortage of people willing to correct them.

      If you don’t have the time to write a blog post, maybe you, or Gregory Benford, can answer just the following question. If someone was going to donate $100k and asked you to pick the charity, would you choose the SIAI? A ‘Yes/No’ answer would be welcome if you are too busy, a short explanation if you’ve the time.

      If someone asked me to pick the charity, I’d probably start by asking why they want me making their decisions for them.

      In general, when people ask me for advice about issues like this, I try to help them achieve what they want to achieve — in their heart of hearts: it may take a while to ferret it out. I try not to use other people’s indecision as an opportunity to get them to become mere extensions of my will. So my natural tendency would be to find out what this person wanted to achieve and help them do it.

      • Desertopa says:

        Would it encourage you to answer the spirit of the original question if I asked what you would do with $100,000 if it were given to you on the condition that you donate it to a charity of your choice?

        • John Baez says:

          Ah, that’s a better question.

          And it’s good that you added the clause “on the condition that you donate it to a charity of your own choice”, because I was all ready with the answer in case you left that out: I’d have said “I’ll save the money for my retirement”. Given the shaky state of California’s economy, I don’t trust the U.C. pension system very much anymore.

          Since I haven’t ever been in the position to donate lots of money to a charity, I haven’t thought much about your question. I want to tackle it when I rewrite my will, but I haven’t yet. So, I don’t have an answer ready.

          If you held a gun against my head and forced me to answer without further thought, I’d probably say Médecins Sans Frontières, because I’m pretty risk-averse. They seem to accomplish what they set out to accomplish, they seem financially transparent, and I think it’s pretty easy to argue that they’re doing something good (as opposed to squandering money, or doing something actively bad).

          Of course, anyone associated with Less Wrong would ask if I’m really maximizing expected utility. Couldn’t a contribution to some place like the Singularity Institute of Artificial Intelligence, despite a lower chance of doing good, actually have a chance to do so much more good that it’d pay to send the cash there instead?

          And I’d have to say:

          1) Yes, there probably are such places, but it would take me a while to find the one that I trusted, and I haven’t put in the work. When you’re risk-averse and limited in the time you have to make decisions, you tend to put off weighing options that have a very low chance of success but a very high return if they succeed. This is sensible so I don’t feel bad about it.

          2) Just to amplify point 1) a bit: you shouldn’t always maximize expected utility if you only live once. Expected values — in other words, averages — are very important when you make the same small bet over and over again. When the stakes get higher and you aren’t in a position to repeat the bet over and over, it may be wise to be risk averse.

          3) If you let me put the $100,000 into my retirement account instead of a charity, that’s what I’d do, and I wouldn’t even feel guilty about it. I actually think that the increased security would free me up to do more risky but potentially very good things!

          Hmm, here’s a better idea:

          Could I get someone to create an institute, register it as a charity, and get the institute to hire me?

    • John F says:

      One avenue of criticism is that the weak vs strong AI transition suffers as much from the sorites paradox as any concept ever.

      http://en.wikipedia.org/wiki/Strong_AI

      Gray goo is unfeasible in an oxidizing atmosphere. If you try to follow the physical chemistry of fuel and transport, you too will be led to suspect that programmed self-reproducing microbots have cell membranes …

      I for one have met our new robot overlords, and they is us.

  9. jack fuller says:

    As we have learned from a number of literally “global” issues lately, it may or may not be good to “fool with Mother Nature”, to quote some famous source somewhere. This is certainly true in regard to political sensibilities that may be involved, say nothing of religious and ideological ones.

    And, indeed, the devils or angels should be given their due. Any proposed massive intervention in nature can be reasonably expected to generate corresponding comment and concern.

    What’s new about this is precisely the fact that it is new in the history of earth and humankind. Thinking and philosophy, not to mention experience, are yet essentially virgin regarding technologies that affect the entire planet.

    However, there does seem to be a fundamental wisdom that can nevertheless be applied in any age, namely to be prepared in our present state of ignorance to sacrifice if necessary a certain amount of what we have in order to better assure a better outcome.

    In other words, to “err on the safe side”.

    Amidst all the talk about “values”, it’s a constant mystery why that very worthy value is not universal among all ideologies. Perhaps, as with all important values, it’s because of the level of courage and potential sacrifice involved.

    • John Baez says:

      Jack wrote:

      “err on the safe side”.

      Amidst all the talk about “values”, it’s a constant mystery why that very worthy value is not universal among all ideologies.

      Well, one reason is that many ideologies propagate themselves in ways that destroy some of the people who hold them. So, to take some currently fashionable examples, you have ideologies that say you should “die for your country” or “become a martyr for your faith”. People who convince other people to embrace these ideologies may get further, at least in the short run, than people who say “err on the safe side”.

      (Imagine an organization called “Al Schmaeda”, based somewhere on the Afganistan-Pakistan border, whose leader constantly says “Allah wants us to err on the safe side”.)

      But a version of “err on the safe side” has become very important in policy debates, where it’s called the precautionary principle. As you’ll see by clicking the link, it’s been accepted by a number of important institutions. However, as you carry this principle toward its logical extremes, it becomes quite controversial. Erring on the safe side can become arbitrarily expensive, depending on how safe you want to be!

      (Of course, a deeper definition of “safe” would not consider it to be safe to spend too much money making the world “safe” in one particular way.)

  10. Giampiero Campa says:

    This is quite off topic, but, let me quote Benford:

    Few doubt that our climate stands in a class by itself in terms of complexity. Though much is made of how wondrous our minds are, perhaps the most complex entity known is our biosphere, in which we are mere mayflies. Absent a remotely useful theory of complexity in systems, we must proceed cautiously.

    I have to say that i don’t really agree with this quote. I mean, unless you want to define complexity as the sheer size of the data, memory or processing power needed to accurately simulate a system, it would seem to me that the richness of the structure of the system has to be taken into account.

    For example, one could argue that the biosphere processes are described by simple equations (e.g. navier-stokes + something else) and that it is just their instability and the size of the problem that makes it challenging.

    On the other hand, really understanding systems like the human genome, a computer, a 10+ million lines program, and to some extent the human brain, is challenging (i think) because their structure is very rich and not really self-similar.

    In other words, the “evolution equations” of these latter systems are much harder to “write down”.

    I don’t know, i hope i was able to express properly my point of view …

  11. Gregory Benford says:

    To Giampiero Campa:

    Agree complexity is hard to define. But genomics, for example, profits from experiments. I know something about this (genescient.com) and suggest that the climate cannot be well understood without experiment, either. Especially on the scales we want to first explore, ~ few thousand km.

  12. Gregory Benford says:

    Jack et al:

    My fave version of the precautionary principle is:

    NEVER DO ANYTHING FOR THE FIRST TIME

    That way, you’re perfectly safe from normal threats. But this isn’t. In geoengineering, we simply do not know how much hesitation is appropriate. We have at best a few decades of Business As Usual.

    Also the precautionary principle supposes that doing nothing is safe, i.e., some kind of equilibrium of threat. But all we know says this is untrue.

  13. Gregory Benford says:

    To John & streamfortyseven:
    Yes, $300 million to do the Arctic for a summer, and deliver several megatons of SO2. Sure, expending jet fuel–very little on a world scale.
    We can toss these numbers around but that’s not the point. If it works, and simulations say it should, the cost/benefit ratio is very small. In the long run, doing nothing (or just carbon restriction, which has consistently failed for obvious reasons) the ratio is large.

    • John Baez says:

      I was asking where these numbers came from: “only a percent or so of the SO2 already in the Arctic troposphere”, “$300 million to do the Arctic for the summer”, and now “several megatons of SO2“. I don’t mind if they’re only approximate; I just think it’s good to see the calculations.

      I can look around for references, of course.

    • streamfortyseven says:

      “if it works, and simulations say it should…” What simulations? Done with what software, what data? Publications? references?

      Several millions of tonnes of SO2 over the course of a summer, using 3 billion litres or 750 million galllons of jet fuel doing it… And how long does the SO2 stay up there in sufficient concentrations before it has to be replenished?

  14. John Baez says:

    A correspondent pointed out that Nathan Myhrvold is also interested in the sulfur dioxide idea. From an interview in New Scientist:

    Q: At the company you co-founded after leaving Microsoft, Intellectual Ventures, you’re working on a solution to climate change…

    A: Yes. As well as inventing for profit, we do inventions for humanity. One of the crazier ones we do is geoengineering. Right now it’s hard to have a good feeling that we’re going to solve the problem of climate change. Maybe the world will get its act together in time. But what if it doesn’t? I think it is prudent to have a back-up plan. One way to stop global warming is to make the sun 1 per cent dimmer. We can’t stop the sun, but if we put a little bit of material high in the atmosphere, we can scatter a little bit of sunlight back into space.

    Q: How would you do this?

    A: With sulphur dioxide. It’s good at scattering light, it’s natural, it’s in volcanoes and there’s lots of it there already. Our contribution was to think, how the hell are you going to get it up there in a way that’s reasonably cheap? We came up with the idea of taking a long hose and putting a string of balloons on it and pointing it up to the sky. All the calculations suggest that it works. That is about as far as we’re going to go with it. Our basic thrust is to get this out there, and hopefully people will take these ideas seriously and test them to see whether they work or not.

    Does anyone know how to find Myhrvold’s paper on this topic? (I’m sure I could do it if necessary…)

  15. Tom Leinster says:

    I don’t know where to find that paper, but I do remember reading about the sulphur dioxide aerosol idea in the much-pilloried final chapter of Superfreakonomics. Myhrvold features prominently there as a proponent of the idea.

    Personally I enjoyed Freakonomics a lot but thought Superfreakonomics was pretty dire. And apparently many climate scientists thought that this final chapter, on “global cooling” and geoengineering, was preposterous. That doesn’t mean that the idea itself is preposterous, of course. But I seem to remember that some of those criticisms of the book contained withering criticisms of Myhrvold’s proposals.

    This is just gossip, though, and obviously the right thing to do is to read up on it – as you’re trying to do.

    • DavidTweed says:

      I remember reading the one of the authors of Superfreakonomics talking about that chapter. IIRC, he basically said that they felt there was a misconception that they were making their own complete analysis of climate change whereas they felt their chapter was “we picked a bunch of people and talked to them, and here’s what we think given what they said” (i.e., they weren’t trying to validate what people told them, just think about the freakonomics side given what they were told).

      Of course, that raises the issue of what the reader would gain from reading the chapter, if it’s based on info that the authors themselves don’t necessarily believe to be accurate and haven’t investigated in detail.

    • John Baez says:

      Tom wrote:

      I seem to remember that some of those criticisms of the book contained withering criticisms of Myhrvold’s proposals.

      This is just gossip, though, and obviously the right thing to do is to read up on it – as you’re trying to do.

      Thanks—I’ll try to read that book and the controversy surrounding it, and then dig back to more serious literature. (I’d be even happier if someone else did, and told me the results.)

      Every proposal I’ve ever seen for any sort of geoengineering scheme has received withering criticism from someone or other. I believe one reason is that lot of people are opposed to geoengineering on principle.

      Indeed, there was an open letter opposing the Asilomar International Conference on Climate Intervention Technologies before it even happened. I think that’s going too far. I think people need to openly discuss geoengineering schemes, and policies regarding geoengineering. If you don’t let people discuss them openly, that’ll just drive the discussion ‘underground’, into realms cloaked by secrecy. Indeed, there are signs that could already be happening.

      Of course, just because a lot of people oppose something on principle, doesn’t mean it’s a good idea!

      But I think it means we have to examine their arguments in detail. It’s too easy to come up with arguments against doing something after you’ve already decided it’s a bad idea. The hard part is determining in some rational manner which idea is worse: some particular geoengineering scheme, or some alternative thing we’re likely to do (like ‘business as usual’).

      One big problem is the shortage of information. That’s why I like Benford’s idea: start doing experiments!

  16. John Baez says:

    Here’s a paper recommended by Gregory Benford, which addresses some of our questions about injecting sulfur dioxide into the stratosphere:

    • Alan Robock, Allison Marquardt, Ben Kravitz, and Georgiy Stenchikov, Benefits, risks, and costs of stratospheric geoengineering, Geophysical Research Letters 36 (2009), L19703.

    It looks quite readable.

  17. The Cosmist says:

    Is the case for climate apocalypse really so clear? Everyone admits that the climate system is incredibly complex and difficult to model, yet a lot of otherwise intelligent people seem prepared to dismantle industrial civilization based on these dubious models. I don’t understand how rational physicists can adopt this position (and of course neither do many eminent physicists, such as Freeman Dyson), but if there are some sources of information that make this clear I would like to read them.

    The predictions of the climate doomsayers have failed repeatedly (see for example James Hansen’s prediction in 1988 of a 2-4 degree temperature rise in the past decade: http://stevengoddard.files.wordpress.com/2011/03/paintimage834.jpg ), but despite their failures they seem to be ever more confident and shrill with every new apocalyptic projection. I don’t have any political agenda here, but to me something about this climate change hysteria doesn’t quite add up — I fear that those driving it *do* have political agendas and their proposed “solutions” are much worse than the original “problem”!

    • John Baez says:

      The Cosmist wrote:

      I don’t have any political agenda here…

      No? Your rhetoric—”climate apocalypse”, “climate doomsayers”—seems designed to get people heated up, rather than start a calm discussion. To borrow a phrase from you, I might almost call this rhetoric “shrill”.

      Personally I prefer a calmer approach. This blog is part of the Azimuth Project. Over on the Azimuth Library, we’ve been trying to compile reliable information on environmental problems and proposed solutions. If you want scientific reports on climate change, I suggest starting here:

      Reports, Azimuth Library.

      If you want to see some seriously considered plans of action, try this:

      Plans of action, Azimuth Library.

      You won’t find the word “apocalypse” anywhere in these reports and plans of action, I think—nor recommendations to “dismantle industrial civilization”.

      It’s true that drastically cutting carbon emissions would require dramatic action. For a good overview of the order of magnitude of this problem, see:

      Stabilization wedges, Azimuth Library.

      However, these measures are nothing like “dismantling industrial civilization”. And you’ll note the Gregory Benford, our interviewee here, is suggesting the possibility of less rapid cuts in carbon emissions coupled with temporary measures to cool the Earth.

    • Nathan Urban says:

      Please restrain your hyperbole. For someone who is supposedly rational, you seem quick to speak of “apocalypse” and “shrill” “hysteria” of people with “agendas”. You will find none of these words in, say, the IPCC report. And no one is talking about “dismantling industrial civilization”.

      As for climate models, they have their limitations, but there isn’t anything dubious about basic energy balance arguments. It’s certainly possible to argue about regional and local impacts. But if you’re talking about plain global warming, the general range predicted is based on estimates of climate sensitivity that are consistent across historical observations, paleodata through shallow and deep time, and the entire hierarchy of climate models.

      It’s common to assert that climate projections have “repeatedly failed”, but the basic picture has not really changed: estimates of climate sensitivity 20-30 years ago are similar to modern estimates, and certainly have not been disproven by subsequent observations.

      Hansen never made a prediction of 2-4 degree temperature rise in the past decade. It is easy to find what he did predict in his published research from that time, using GISS Model II. The newspaper article undoubtedly made a typo, either meaning 0.2-0.4 degrees/decade, or 2-4 degrees/century.

      • John Baez says:

        Nathan wrote:

        Hansen never made a prediction of 2-4 degree temperature rise in the past decade.

        After breakfast, I planned to look at the link provided to see what it said. The idea of Hansen claiming a 2-4 degree increase in one decade seemed completely at odds with everything I’ve read by him. For example, in 1993 Hansen estimated a temperature increase of 3±1°C for a doubling of carbon dioxide in the atmosphere—something that’ll take considerably longer than one decade to occur.

        Now I’ve had breakfast. I now see the link points to a newspaper article, not something Hansen wrote. The article is wrong. If ‘the Cosmist’ thinks otherwise, he should look at Hansen’s papers, which are publicly available, and show us where he made this supposed prediction.

        • Phil Henshaw says:

          I keep pointing to the underlying error in the assumptions of the climate mitigation model. The purpose of mitigation is to perpetuate an economy that naturally needs ever growing energy use.

          That’s what it is. That’s what it’s always been. That’s what won’t work at all except to generate hidden liabilities even greater than climate change. If you “automatically disbelieve” that, consider what happens if we exhaust our affordable energy resources without rebuilding our economy to run on expensive energy…

    • Phil Henshaw says:

      Cosmist… You seem to misunderstand the reasons why scientists believe in trying to project the consequences of natural processes. It’s because nature is out of our control, and not in any way shape or manner dependent on our theories.

      I grant that given the difficulty you express with the theory suggests even scientists might only have a slim chance of being right. Finding useful theories, though, is the only option available that would allow us to escape the consequence of walking straight into total disasters.

      To put it into the vernacular, it’s the standard precautionary principle that any wife or mother uses that’s being applied here. If think you are going to invite more people home for dinner than she thinks she has food to offer, you’ll get a good tongue lashing.

      If you object and just say you’re sure she could find more, and you’re coming with your gang anyway, you’re likely to find a locked or empty home to come to, as she will not be able to help you.

  18. [...] course, any generalization this vast admits many exceptions. I like Gregory Benford because he confounds naive expectations: he thinks global warming is a desperately urgent problem [...]

  19. [...] is what mathematician and climate activist John Baez has to say: Of course, anyone associated with Less Wrong would ask if I’m really maximizing [...]

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