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A biased economic analysis of geoengineering

Filed under: — group @ 11 August 2009 - (Español)

Guest commentary by Alan Robock – Rutgers University

Bjorn Lomborg’s Climate Consensus Center just released an un-refereed report on geoengineering, An Analysis of Climate Engineering as a Response to Global Warming, by J Eric Bickel and Lee Lane. The “consensus” in the title of Lomborg’s center is based on a meeting of 50 economists last year. The problem with allowing economists to decide the proper response of society to global warming is that they base their analysis only on their own quantifications of the costs and benefits of different strategies. In this report, discussed below, they simply omit the costs of many of the potential negative aspects of producing a stratospheric cloud to block out sunlight or cloud brightening, and come to the conclusion that these strategies have a 25-5000 to 1 benefit/cost ratio. That the second author works for the American Enterprise Institute, a lobbying group that has been a leading global warming denier, is not surprising, except that now they are in favor of a solution to a problem they have claimed for years does not exist.

Geoengineering has come a long way since first discussed here three years ago. [Here I use the term “geoengineering” to refer to “solar radiation management” (SRM) and not to carbon capture and sequestration (called “air capture” in the report), a related topic with quite different issues.] In a New Scientist interview, John Holdren, President Obama’s science adviser, says geoengineering has to be examined as a possible response to global warming, but that we can make no such determination now. A two-day conference on geoengineering organized by the U.S. National Academy of Sciences was held in June, 2009, with an opening talk by the President, Ralph Cicerone. The American Meteorological Society (AMS) has just issued a policy statement on geoengineering, which urges cautious consideration, more research, and appropriate restrictions. But all this attention comes with the message that we know little about the efficacy, costs, and problems associated with geoengineering suggestions, and that much more study is needed.

Bickel and Lane, however, do not hesitate to write a report that is rather biased in favor of geoengineering using SRM, by emphasizing the low cost and dismissing the many possible negative aspects. They use calculations with the Dynamic Integrated model of Climate and the Economy (DICE) economic model to make the paper seem scientific, but there are many inherent assumptions, and they up-front refuse to present their results in terms of ranges or error bars. Specific numbers in their conclusions make the results seem much more certain than they are. While they give lip service to possible negative consequences of geoengineering, they refuse to quantify them. Indeed, the purpose of new research is to do just that, but the tone of this report is to claim that cooling the planet will have overall benefits, which CAN be quantified. The conclusions and summary of the report imply much more certainty as to the net benefits of SRM than is really the case.

My main areas of agreement with this report are that global warming is an important, serious problem, that SRM with stratospheric aerosols or cloud brightening would not be expensive, and that we indeed need more research into geoengineering. The authors provide a balanced introduction to the issues of global warming and the possible types of geoengineering.

But Bickel and Lane ignore the effects of ocean acidification from continued CO2 emissions, dismissing this as a lost cause. Even without global warming, reducing CO2 emissions is needed to do the best we can to save the ocean. The costs of this continuing damage to the planet, which geoengineering will do nothing to address, are ignored in the analysis in this report. And without mitigation, SRM would need to be continued for hundreds of years. If it were stopped, by the loss of interest or means by society, the resulting rapid warming would be much more dangerous than the gradual warming we are now experiencing.

Bickel and Lane do not even mention several potential negative effects of SRM, including getting rid of blue skies, huge reductions in solar power from systems using direct solar radiation, or ruining terrestrial optical astronomy. They imply that SRM technologies will work perfectly, and ignore unknown unknowns. Not one cloud has ever been artificially brightened by injection of sea salt aerosols, yet this report claims to be able to quantify the benefits and the costs to society of cloud brightening.

They also imply that stratospheric geoengineering can be tested at a small scale, but this is not true. Small injections of SO2 into the stratosphere would actually produce small radiative forcing, and we would not be able to separate the effects from weather noise. The small volcanic eruptions of the past year (1.5 Tg SO2 from Kasatochi in 2008 and 1 Tg SO2 from Sarychev in 2009, as compared to 7 Tg SO2 from El Chichón in 1982 and 20 Tg SO2 from Pinatubo in 1991) have produced stratospheric clouds that can be well-observed, but we cannot detect any climate impacts. Only a large-scale stratospheric injection could produce measurable impacts. This means that the path they propose would lead directly to geoengineering, even just to test it, and then it would be much harder to stop, what with commercial interests in continuing (e.g., Star Wars, which has not even ever worked).

Bickel and Lane also ignore several seminal papers on geoengineering that present much more advanced scientific results than the older papers they cite. In particular, they ignore Tilmes et al. (2008), Robock et al. (2008), Rasch et al. (2008), and Jones et al. (2009).

With respect to ozone, they dismiss concerns about ozone depletion and enhanced UV by citing Wigley (2006) and Crutzen (2006), but ignore the results of Tilmes et al. (2008), who showed that the effects would prolong the ozone hole for decades and that deployment of stratospheric aerosols in a couple decades would not be safe as claimed here. Bickel and Lane assert, completely incorrectly, “On its face, though, it does not appear that the ozone issue would be likely to invalidate the concept of stratospheric aerosols.”

With respect to an Arctic-only scheme, they suggest in several places that it would be possible to control Arctic climate based on the results of Caldeira and Wood (2008) who artificially reduce sunlight in a polar cap in their model (the “yarmulke method”), whereas Robock et al. (2008) showed with a more realistic model that explicitly treats the distribution and transport of stratospheric aerosols, that the aerosols could not be confined to just the Arctic, and such a deployment strategy would affect the summer Asian monsoon, reducing precipitation over China and India. And Robock et al. (2008) give examples from past volcanic eruptions that illustrate this effect, such as the pattern of precipitation reduction after the 1991 Pinatubo eruption (Trenberth and Dai, 2007):

With respect to cloud brightening, Bickel and Lane ignore the Jones et al. (2009) results that cloud brightening would mainly cool the oceans and not affect land temperature much, so that it is an imperfect method at best to counter global warming. Furthermore Jones et al. (2009) found that cloud brightening over the South Atlantic would produce severe drought over the Amazon, destroying the tropical forest.

They also ignore a huge class of ethical and world governance issues. Whose hand would be on the global thermostat? Who would trust military aircraft or a multi-national geoengineering company to have the interests of the people of the planet foremost?

They do not seem to realize that volcanic eruptions affect climate change because of sulfate aerosols produced from sulfur dioxide gas injections into the stratosphere, the same that is proposed for SRM, and not by larger ash particles that fall out quickly after and eruption and do not cause climate change.

They dismiss air capture (“air capture technologies do not appear as promising as solar radiation management from a technical or a cost perspective”) but ignore the important point that it would have few of the potential side effects of SRM. Air capture would just remove the cause of global warming in the first place, and the only side effects would be in the locations where the CO2 would be sequestered.

For some reason, they insist on using the wrong units for energy flux (W) instead of the correct units of W/m^2, and then mix them in the paper. I cannot understand why they choose to make it so confusing.

The potential negative consequences of stratospheric SRM were clearly laid out by Robock (2008) and updated by Robock et al. (2009), which still lists 17 reasons why geoengineering may be a bad idea. One of those important possible consequences, the threat to the water supply for agriculture and other human uses, has been emphasized in a recent Science article by Gabi Hegerl and Susan Solomon.

Robock et al. (2009) also lists some benefits from SRM, including increased plant productivity and an enhanced CO2 sink from vegetation that grows more when subject to diffuse radiation, as has been observed after every recent large volcanic eruption. But the quantification of these and other geoengineering benefits, as well as the negative aspects, awaits more research.

It may be that the benefits of geoengineering will outweigh the negative aspects, and that most of the problems can be dealt with, but the paper from Lomborg’s center ignores the real consensus among all responsible geoengineering researchers. The real consensus, as expressed at the National Academy conference and in the AMS statement, is that mitigation needs to be our first and overwhelming response to global warming, and that whether geoengineering can even be considered as an emergency measure in the future should climate change become too dangerous is not now known. Policymakers will only be able to make such decisions after they see results from an intensive research program. Lomborg’s report should have stopped at the need for a research program, and not issued its flawed and premature conclusions.


Jones, A., J. Haywood, and O. Boucher 2009: Climate impacts of geoengineering marine stratocumulus clouds, J. Geophys. Res., 114, D10106, doi:10.1029/2008JD011450.

Rasch, Philip J., Simone Tilmes, Richard P. Turco, Alan Robock, Luke Oman, Chih-Chieh (Jack) Chen, Georgiy L. Stenchikov, and Rolando R. Garcia, 2008: An overview of geoengineering of climate using stratospheric sulphate aerosols. Phil. Trans. Royal Soc. A., 366, 4007-4037, doi:10.1098/rsta.2008.0131.

Robock, Alan, 2008: 20 reasons why geoengineering may be a bad idea. Bull. Atomic Scientists, 64, No. 2, 14-18, 59, doi:10.2968/064002006. PDF file Roundtable discussion of paper

Robock, Alan, Luke Oman, and Georgiy Stenchikov, 2008: Regional climate responses to geoengineering with tropical and Arctic SO2 injections. J. Geophys. Res., 113, D16101, doi:10.1029/2008JD010050. PDF file

Robock, Alan, Allison B. Marquardt, Ben Kravitz, and Georgiy Stenchikov, 2009: The benefits, risks, and costs of stratospheric geoengineering. Submitted to Geophys. Res. Lett., doi:10.1029/2009GL039209. PDF file

Tilmes, S., R. Müller, and R. Salawitch, 2008: The sensitivity of polar ozone depletion to proposed geoengineering schemes, Science, 320(5880), 1201-1204, doi:10.1126/science.1153966.

Trenberth, K. E., and A. Dai (2007), Effects of Mount Pinatubo volcanic eruption on the hydrological cycle as an analog of geoengineering, Geophys. Res. Lett., 34, L15702, doi:10.1029/2007GL030524.

329 Responses to “A biased economic analysis of geoengineering”

  1. 301
    Patrick 027 says:

    Steve, I’m sorry but brevity didn’t seem to be working. It’s gold but not iridium. The stream-of-consciousness quality is a result of my trying to be fast and allow some loose ends (…) to avoid too much detail; I have thought about these things before.

    A few points of clarification/correction on the ‘ideal’ free market health insurance:

    0. Some genetic conditions are not inherited – though they might have inheritable probability, which is what would be charged for (same for inheritable epigenetic risks). Actually, parental decisions regarding child lifestyle, place of residence, etc, could be lumped into the same formulation (?).

    “charge per act of unprotected you-know-what” …, “multiplied on a time-of-month variation”

    … more generally, any variation in fertility, including ongoing pregnancy – and also, given that all actions to achieve pregnancy only lead up to one pregancy at a time at most, those should be counted differently (?). Twins would be two-for-one, unless behaviorally dependent, or genetic factors for multiples, etc. Adjustments for whether pregnancy is carried to term or not, etc, since the medical costs covered by insurance would be distributed over time… it gets complicated as the real world is complicated, though the principles are easy enough to understand.

    (and in fairness to Palin, who might not actually have been demonstrating soci-ali-st tendencies, depending on where the emphasis should be placed in here statements (ie of course insurance companies ration care based on how much a customer is worth to society, as measured by how much the person can pay or have someone pay for him/her self (setting aside when they cheat their customers) – but admitedly that is different than ‘subjective judgements (or is it?) – of course it is still a strawman argument she was waging):

    The free market can determine that the cost of such an idealized free market system is too great for the benifit. People could choose not to get such an insurance plan, not wanting to deal with the totalitarian nature of it and various psychological and even potentially moral discomforts (?). The monetary impact is a reduced willingness to pay. The insurance company might not be able to make a profit with that type of plan, so the plan won’t be sold. Two alternatives are to just treat genetic risks as unknown (would actually save on genetic information costs), and cover the related costs with an equal charge per customer – or to not cover pre-existing conditions. Even if it is outlawed (PS public policy) to discrimate based on genetics directly, any determination of expense based on a medical exam would not presumably off a discount if the high blood pressure was hereditary as opposed to due to chosen behavior, and therefore would be more unfair to some people.

    In general, accuracy has cost; sometimes the better option is a less accurate approximation that has less cost. This applies to AGW policy – if we can’t determine whether the emissions tax should be $10 per ton CO2 or $500 per ton of CO2 … well let’s just go with something in between, or since we are at zero, start lower and adjust depending on results or lack thereof and other new information.


    Other point –

    If you tried to buy love, it would be devalued. But suppose you wanted the chance to fall in love with someone who wanted to fall in love with someone who knew a lot about AGW. Well, then you might want to invest in yourself, specifically in your knowledge of AGW. At some point you might buy a book, or buy biofuel or electricity or food to fuel your transport to the library (although one of those has a nice additional benifit), or buy internet service, etc. You might spend some freetime studying, trading some other opportunity/use of time for that purpose. You would also try to stay alive.

    You would take care of your eyes, buy glasses, or bionic vision someday, to enjoy scenery. Etc.


    End general economics. As long as the subject matter has turned this way, if this is still open in a few days, I might post a more specific idea for AGW policy.

  2. 302
    CM says:

    Interesting comment by the chair of the Royal Society geoengineering study on the “moral hazard” argument against geoengineering (which I for one have raised a couple of times in this thread):

    While we need to take seriously the possibility that geoengineering will undermine efforts to reduce emissions, it is based on an assumption which has not yet been tested empirically. Indeed, it is possible that geoengineering could have the opposite effects. … Feedback during the focus groups [conducted for the study] suggested that the very notion that something as drastic as geoengineering may be required dramatically underlines the seriousness of the problem.

    (John Shepherd, “Do mention the ‘G’ word”, New Scientist, 5 Sep 09 / online 3 Sep)

    More study needed, no doubt.

  3. 303
    CM says:

    Mark (re #291), I did read Stephanie’s original comment (#216). She didn’t say that, either.

    I do appreciate your point that, if the civilization that support our whole money system is at stake, monetary valuations are a questionable guide to policy. The effects of climate change can be game-changers, and it raises questions of equity on global and centennial scales. The IPCC discusses some of the difficulties (AR4 WG3, ch. 2).

    Cost-benefit analysis may be a useful tool in many policy settings, like health care in a single country with a narrow range of welfare levels. It seems an important tool to assess and prioritize mitigation options in, say, the energy sector. But I don’t feel at all confident it can scale up to the big strategic issues in global warming policy — such as what role if any should be allowed for geoengineering.

  4. 304
    David B. Benson says:

    Oh, I should have put this geoengineering idea here.

    Irrigated afforestation of the Sahara and Australian Outback to end global warming

    Various potential side-effects are mentioned and some briefly analyzed. For example, to protect fisheries it seems that coastal Mauritania needs to remain desert.

  5. 305
    Mark says:

    re 303, so I missed that one.

    Read 255.

  6. 306
    Stephanie says:

    Mark, I think a number of other people have pointed out that you’re (deliberately) misconstruing my post and you don’t seem to have any interest in what I’m actually saying, so I can’t see the point in responding any further to your comments.

    #279 and 280: Ray and Kevin both summed it up well. “But in the case of AGW cost benefit analysis (CBA, in the jargon, apparently) we have cost estimates that range from 3% to 40% of global GDP. (As far as I can tell so far, all of the estimates are pretty shaky.) If we’re talking about the higher end of the range, though, we’re talking about negative economic growth. And if we get that, we get a situation where the logic for discounting gets turned upside down–”paying later” becomes proportionately more and more expensive.”

    In this case you’d be talking about a negative component to the discount rate. (Not to get too technical, but I think you all can handle this: one method for determining the discount rate is r = rho + eta*growth, where rho is the “pure rate of time preference” and eta is the “elasticity of the marginal utility of consumption” where rho and eta are both measured empirically. If growth is negative, you could indeed witness a negative discount rate.)
    Several other issues arise here, not least of which that rho and eta are both generally measured in an intra-generational context, whereas climate change is clearly an inter-generational public good, and therefore traditional measurements of rho and eta may not apply.

    When I mentioned that there has to be some balancing, that does not imply that we ignore the future damages, rather we have to recognize that it is not feasible to spend every dollar today to prevent all damages in the future. We do have to eat and protect ourselves from the elements, or there will be no future humans.

    #285: Hank: “Has anyone seen a pure economic analysis of the use of lead in paint and plumbing, making the arguments for and against continuing to use it?”
    I’m sure there has been and the benefits of banning it far exceeded the costs associated with replacing it and living with “inferior” substitutes. Lead in paint does cause increased lead-blood levels and there is a statistically significant association between blood-lead levels and IQ and academic performance.

    #287, Patrick: “Perhaps this is a case where there is too much nonlinearity to assign a cost that is independent of the future trajectory.”
    I think that’s probably an accurate statement. We need to make assumptions about what the future emissions trajectory will be, and that is part of (though not remotely completely) where the uncertainty in the estimates of future damages comes from. As I see it, all we can do is reevaluate periodically. Given the massive uncertainties surrounding the damages associated with climate change, and our presumably increasing knowledge, this would be necessary at any rate.

  7. 307
    Mark says:

    > Mark, I think a number of other people have pointed out that you’re (deliberately) misconstruing my post

    No, they’ve pointed out I’ve misconstrued.

    Please show this is deliberate.

  8. 308
    Ray Ladbury says:

    Actually, the case of catastrophic deflation due to climate change might be analogous to the sort of deflation that took place in the late dark ages/early middle ages. Populations decreased so severely that there was no one to work the land, which therefore lay fallow, leading to more starvation and deflation. Of course we are starting from a much higher population, but still, we might draw some lessons.

  9. 309
    Mark says:

    Ray, the plague killed off so many people that there weren’t enough to work the land.

    Therefore the landowners had to compete for workers.

    It ended serfdom.

    Problem is, we’ve taught hunters how to do cost accountancy but we haven’t taught cost accountants how to hunt.

    This is not good.

    Well, except for the hunted animals. Selfish little beggars…

  10. 310
    Patrick 027 says:

    “Populations decreased so severely that there was no one to work the land”

    However, there would be less demand for the products of worked land, and the remaining land workers, in an ideal situation (obviously not applicable to the historical context), would select the best land (within other constraints) so that there would be more food per unit land-work (Mao forgot that part, in his (Stossel-pronatalism and Republican-populist anti-intellectualism) expectation that more work always gives more food without any upper limit). Aside from variations in output/input ratio, however, one might expect a near balance between population and food production. Except:

    1. If the population starts to drop with an initial famine, the dropping population could sustain the famine, sustaining continued decline, whereas if the population drops initially without an initial famine, there could be an initial food surplus (?)


    2. If the population is starts to drop via illness that decreases productivity
    3. If population reduction by itself (via shrinking labor pool) or in combination with illness (reduction of trade – lower population density itself might reduce the linkages among populations, while fear of disease would be an impediment to trade on various scales

    (as in the scenario presented in ABC’s “Earth 2100”, which is the most depressing, most frightenning version of the near-future I have ever seen, in large part because it was so plausable and could so easily occur (unlike “Supervolcano” (realistic but unlikely within any one century) or “The Day After Tomorrow” (hyperbole and technical impossibilities with implausably happy ending for that scenario, relatively speaking), or “Armageddon” (unlikely-big threat, implausable happy ending, although I found the visual effects for the impact on Paris to be quite realistic), or “The Core” (besides motion in the outer core sustaining a magnetic field, everything else salient is just wrong – the core would never just stop, the magnetic field would take ~ 10(0?),000 times as long to decay if it did, and the effects would be nothing like what was depicted, except the part with the Northern lights, which would be fun) – all good movies nonetheless)

    reduces the efficiency increases that can be realized with specialization (including those who specialize in preserving accumulated knowledge).

    4. The proportions of labor shift,
    5. or if other feedbacks with a short time scale overwhelm adaptation capacity, so that overall behavior becomes self destructive (the prospect that someone will steal your food decreases the motive to produce any food – ie Congo within the last ~decade).

  11. 311
    Hank Roberts says:

    Stephanie, re 285, either you missed the irony or you missed the cost accounting — you’re adding accounting for externalized costs, and that’s not yet done very well. It takes public health action to deal with problems like lead plumbing and lead paint, because no accountant anywhere is going to tell her employer that they should take externalized costs into their bookkeeping and cut shareholder short-term profit. Not til the law forces it.

  12. 312
    Hank Roberts says:

    ps for Stephanie:


    “… new paint in many unregulated Asian countries greatly exceeds U.S. safety levels.

    The UC-led team analyzed 80 consumer paint samples of various colors and brands from four countries–India, Malaysia, China and Singapore–to determine the amount of lead and compare them with U.S. standards.

    About 50 percent of the paint sold in China, India and Malaysia–none of which appear to have regulations on lead–had lead levels 30 times higher than U.S. regulations. In contrast in Singapore, which has well-enforced regulations, only 10 percent of paint samples were above U.S. regulations, the highest being six times the U.S. limit….”

  13. 313
    Patrick 027 says:

    (It doesn’t require people stealing other peoples food to reduce food productivity – what can happen during war is deliberate destruction of farmland; the potato (growing underground) is harder to destroy, so growing potatos would give an adantage to people – potatos might also have been easier to grow than other crops in some climate conditions; however, some in Europe, such as in France, did not want to eat potatoes, for cultural/religious reasons, though the King tried to get them to do so.)

    (“so that overall behavior becomes self destructive ” – this can occur even when individuals or smaller groups act perfectly rationally – as in a negative sum game.)

    (PS what I understand (?) (feel free to correct me) of the transition from antiquity to middle ages:

    1. productivity of land decreased due to reduced soil fertility
    2. upper-class Romans poisoned themselves (via food, drink, and make-up) with lead, reducing their own fertility, intelligence, and sanity.
    3. Romans didn’t want to fight their own battles anymore, greater reliance on mercenary armies (?) (or slaves – not sure about that part).
    4. Was the empire just too big, geographically, to be sustainable?
    5. Huns, Goths, etc.
    6. Some type of century-millenial scale climate variation
    7. volcanic eruption ~ 535 AD causes short term climate change that is hypothesized to have given cattle (and people with cattle) advantage over horses (and people with horses) in central Asia, driving Avars out, Avars attack remaining portion of Roman Empire (now Byzantine Empire); also, changes in hydrology drive migration on Arabian peninsula that is linked to origin of Islam; also, climate change causes ecological disruption in Africa that might be origin of Bubonic Plague, plague spreads among those linked to Roman empire including Celts in Brittain but not so much Germanic tribes, so Germanic tribes come to dominate Brittain, meanwhile Plague depopulates regions allowing subsequent faster spread of Islam … etc.)

  14. 314
    RichardC says:

    307 Mark, he put parentheses around (deliberately) to show that it was only his opinion. That’s two misconstrues. Baseball, anyone?

    308 Ray, global warming or nuclear war would avoid the anti-societal influence of a plague. Also, we have pretty much filled up the planet resource-wise and prime-space-wise, so our production of food depends mostly on capital, water and land availability. Keeping enough farmers trained isn’t a problem. What if we use geoengineering to control temperatures and the oceans as we know them die? Simple sea lettuce rotting on a beach just killed a French horse and possibly a lorry driver. (That was from increased agricultural runoff, not CO2) Some say the increase in jellyfish is a harbinger of an anoxic event. Coastlines could become horrible places to live.

  15. 315
    Ray Ladbury says:

    Mark says of the Black Death: “Therefore the landowners had to compete for workers. It ended serfdom.”

    Actually, no. Serfdom was around until the Enlightenment in Western Europe and until the beginning of the late 1800s in Russia and some of the Austro-Hungarian Empire. Initially, the landowners did compete for labor, offering very favorable terms and protection to workers who bound themselves to the land. Once bound, they became serfs.

    Also, while Plague was a large contributor to the die-off, famine was also significant, and one of the causes of the famine was the insecurity of farms with a continent full of marauding men at arms in the power vacuum after the fall of Rome.

    RichardC, I think we will find some parallels as our own population starts to decline. Just look at Eastern Europe now.

  16. 316
    Patrick 027 says:

    “Keeping enough farmers trained isn’t a problem.”

    Retraining existing farmers could be a problem. In one case (see “Against the Grain” by Richard Manning), farmers just couldn’t believe the results of a demonstration using sufficient but not excessive fertilizer, and continued out of habit or fear to practice the excessive status quo.

    Stephanie – maybe you could help me with this. You have “one method for determining the discount rate is r = rho + eta*growth, where rho is the “pure rate of time preference” and eta is the “elasticity of the marginal utility of consumption” where rho and eta are both measured empirically. If growth is negative, you could indeed witness a negative discount rate.)”

    Okay. For small scale intragenerational issues (setting aside the philosophical point that we are not exactly the same people from one moment to the next, so one could argue we really have obligations to our future selves, etc, and doing addictive drugs is an infringement on your future self’s freedom, but anyway…), it makes sense that there would be some pure time preference because of uncertainty in the future (that I could die tomorrow) – however, at the societal level this uncertainty should tend to be smaller, or could be made smaller by agreements to shape future trajectories (a feedback)).

    The net cost of climate change is the difference between what will be and what could have been. The uncertainty could be incorporated into that equation using probabilistic descriptions.

    If climate change contributes to a population and economic decline, that is part of the cost of climate change. However, if there is a population and economic decline, the cost of climate change for the time period could be reduced (not in proportion necessarily – for a given change in natural resources, a given population decline could result in greater than in proportion decline in the cost of climate change because of increased migration options and decreased ease of disease transmission, among other things perhaps. However, while a purely utilitarian calculation reduces the costs to people by reducing the number of people (who never existed in the first place – if we get into potential people we could end up regarding every moment spent not copulating with fertility drugs as mass murder, but anyway), the remaining people would experience the changed conditions and in fairness to them some additional moral value conceivably should be assigned; also, there could be a population recovery beyond that which would have to deal with the conditions they are dealt – or even if humans go extinct, if some other beings came upon the scene in the not too distant future (getting into tricky territory here, considering dolphins and apes – then again, we can’t give the same moral weight to individual dolphins if they do not abide by a moral code (how do dolphins treat each other? Well I guess it varies among species and individuals …) – however, we humans might prefer to leave things less of a mess than more of a mess even if we are not there to see it, regardless of obligations or lack thereof to nonhuman entities). There are also costs of depopulation, such as reduced specialization and mass market advantages and opportunities for niche markets, loss of ability to preserve knowledge of the past (a loss for us – while some of us might not experience it directly, it increases our hope for being remembered and known in some way if we can expect conditions to allow it, so…) (also a loss to the future who might learn from us, even possibly the distant future, even perhaps some distant bionic amphibious flying centaur/mermaid descendants of us or others if we go extinct, who excavate the remnants our civilation, buried in hundred million-year old sandstones, limestones, and lava flows, etc. (what minerals would metamorphic cell phones be made of?), and potential loss of human biodiversity, which could have a medical cost to future generations (although given the recent population explosion, assuming depopulation is not too unevenly distributed among populations, any loss in human genetic diversity going down to … 500 million (?) … would not be particularly more special than what could quickly be replaced with a population recovery.

    That being aside from the process of population decline, however (reduced life expectancy a problem; a reduction in birth rate not so much (which can be achieved by a combination of reduced fertility rate and increased generational spacing in time), and the ramifications of any change too rapid for easy adaptation, climate or economic or societal or all.

    But a negative growth, while itself being a cost of climate change, could also reduce the subsequent costs of climate change, and that would go for a negative growth rate due to some independent cause.

    …Except for the effect that greater economic power per person could reduce some of the costs of climate change by decreasing the net cost of adaptation – and/or it’s effect on standard of living, which might be one of the most straightforward metrics to use, if it can be defined well. This may include greater ease of adapting crops and other production/distribution processes to climate shifts due to greater economic resources including technological advances and reduced political tensions that could otherwise lead to self-destructive behavior for the whole of humanity. There is also the possibility of shifts in consumer demand – if the joys of cyberspace became great enough people might be able to make up for losses in physical reality, although I find that depressing so it is a cost to me. (PS I think we should assume most Earth people will continue to be largely carbon based organisms with dietary and psychological, etc, requirements and wants similar to those of most present day Earth people.)

    What do you think?

  17. 317
    Patrick 027 says:

    “setting aside the philosophical point that we are not exactly the same people from one moment to the next, ”

    Or maybe don’t set that aside – I guess that’s part of the reason for the pure time preference (If I don’t know me 50 years from now, I can’t plan his wellbeing as effectively as my own now. But I know that me 50 years from now, if he exists, will not be happy with me now if I don’t do enough for the future me…)

  18. 318
    Patrick 027 says:

    (Of course, some of what I do for myself now will benifit me in the future, and some of what I do for my future will benifit me now, just as it can benifit others to do something for me and can benifit me to do something for others.)

    Not that this doesn’t require the same analysis, but it might in some way be easier to just try to optimize our time-integrated reality from now to as far as we can work with to whatever degree we can work with it – and if we get it right, whatever net price signal is imposed on emissions will be, by free market logic, the true cost, up to the limitations of market accuracy, etc.

  19. 319
    Patrick 027 says:

    … It might be argued that we have a moral responsibility to ourselves in part because we are something special.

    … regarding preservation of nature and natural trajectories, when all else is equal, it makes sense to preserve because it is hard to go home again – ie you can’t just jump back and forth among different geological time divisions (aside from the aesthetic and scientific value of a natural state). On the other hand, natural trajectories will eventually bring about change, and even new geologic time divisions, so the preservation justification has a time decay (aside from aesthetic and scientific value) …

  20. 320
    Patrick 027 says:

    “It might be argued that we have a moral responsibility to ourselves in part because we are something special.”

    That was not what I meant – not that we don’t have moral responsibility to ourselves (although often it is the easy choice type – we can do the right thing for us and others without much effort in various everyday activities, so we don’t think of it as being moral).

    But what I meant was

    It might be argued that we have a moral responsibility not just to us, to preserve ourselves and our accomplishments, because we are something special, even if there is no other thing in particular to have responsibility towards.

  21. 321
    Mark says:

    OK, Ray, I knew that there were still “serfs” in name, but what I read from the discussion on that form of the institution was very different from serfdom before the huge die-off. It could be that such serfdom wasn’t all that different, but I suppose it depends on what historian you read and how you read it.

    NOTE: a die-off that wouldn’t have been so problematic if the concentration of wealth and the reduction of “productive workers” hadn’t been worsened by technology advances. The rich have much more to lose and could not do the work required. Someone on the poverty line doesn’t have much to lose, and if they can still get their own food, falling isn’t possible without external force. We’re in a much worse situation now. How many of us could grow our own food to feed us and our family? Without technology and its required infrastructure (set to a coastline roughly where it has been for the last 200 years), we wouldn’t survive and the powerful would be able to look after themselves but would have to put up with a much MUCH lower standard of living.

    Or pay thugs to take what they wanted from the dregs of society, trading the future of their family for comfort now.

    Who thinks long-term thinking would win here?

  22. 322
    Mark says:

    “307 Mark, he put parentheses around (deliberately) to show that it was only his opinion. ”

    Or was it?

    Are you reading something in, because I can’t find any grammar or IRC norm that says that’s how you indicate it.


    would fit that.



    bare parethesis is often used to indicate sotto voce, but that’s not opinion.

  23. 323
    Mark says:

    On this one:
    “2. upper-class Romans poisoned themselves (via food, drink, and make-up) with lead, reducing their own fertility, intelligence, and sanity.”

    MUCH earlier than that.

    Ancient Egypt used Arsenic and Digitalis for cosmetic reasons and, because the royal family were the children of the Gods and reincarnations thereof, they HAD to interbreed, lest they send the holy spirits into the unenlightened or diluted the holy soul.

    And the poor did just as badly, with their limited resources.

  24. 324

    The primary reason the Roman Empire in the west fell was insufficient civilian control of the military. When social problems arose, every General thought he could do a better job as Emperor than the sitting Emperor, and tried to take over. If he couldn’t do that, he tried to split off a piece of the Empire. The Romans spent more time fighting each other than fighting the external enemies, who took advantage of the situation to chip away at the borders of the Empire until they worked their way to the center. When the Gothic king, Odoacer, finally took Rome in 476 BC, he didn’t even bother to fire the last western Emperor, Romulus Augustulus. He just told him to go home.

    The bit about degeneracy and insanity doesn’t really explain anything. The Roman upper classes were degenerate and insane from the get-go. Caligula was around in the 40s AD; the Empire fell more than 400 years later. And the Empire in the east, now called the Byzantine Empire, lasted until the Turks took it over in 1453, with outposts holding out till 1461. Technically, the monastery at Mt. Athos, which is on an isolated island, is still the Roman Empire, though in practice the monks have to pay taxes to Italy.

  25. 325
    Mark says:

    “The primary reason the Roman Empire in the west fell was insufficient civilian control of the military.”

    Somewhat engendered by the unfortunate side effect of power concentration of people who used to think “I can do better therefore I’m in charge” changed their idea to “I’m in charge, so I do it better”.

    Tony Blair did this to a T.

    He became right purely because he was in charge.

    And therefore anyone disagreeing was wrong.

    And also in the rulers of Rome becoming completely hatstand.

  26. 326

    Fascinating factoid, BPL! I can’t forbear to mention that the Romans also had financial problems due to dysfunctional taxation mechanisms.

    Maybe the takeaway is that many disparate factors worked synergistically to bring down the Empire, accounting for the fact that historians have been arguing about “the cause” at least since the days of Gibbon.

    And maybe another takeaway is that a society’s response to climate change–as mentioned WRT Imperial Rome by Patrick in his comment–can be seriously constrained by structural and economic factors, or by leadership failures.

    Relevant for us.

  27. 327
    Patrick 027 says:

    “It might be argued that we have a moral responsibility not just to us, to preserve ourselves and our accomplishments, because we are something special, even if there is no other thing in particular to have responsibility towards.”

    If true, that would likely also apply to some moral value of preservation regardless of who is served by it. (Preservation of nature, however, means also allowing the next ice age to occur without interference.)


    While preservation has some more direct (aside from the economic effects and their repurcusions of adapting or losing infrastructural value in a rapid change) aesthetic and scientific value, there is also direct aesthetic and scientific value to AGW, in that ‘may you live in interesting times’ is both a blessing and a curse (think storm chaser videos), and AGW can be studied by science. However, there may be decreasing returns of both science and excitement with each incremental increase in AGW, and in addition to no longer studying the climate in a ‘natural state’ (or whatever remains of that), some paleoclimatic records would be lost (ice cores – although geologists would have easier access to the rock record in some cases), and biodiversity and ecosystems (although the die-off/changes could be studied). Of course I am not trying to suggest that such silver linings would outweigh the direct losses in nature as well as the net losses from ecosystem and climate services , ecosytsto the economy, etc (medical/health and agricultural resources, water and trade, physical comfort, property and infrastructure value, etc.), but just mentioning them for the sake of greater completeness.

  28. 328
    Patrick 027 says:

    Of course, each effect of climate change in isolation would be modulated by other effects. Other changes modulate the cost of climate change and climate change modulates the other changes.

    “However, while a purely utilitarian calculation reduces the costs to people by reducing the number of people (who never existed in the first place – if we get into potential people we could end up regarding every moment spent not copulating with fertility drugs as mass murder, but anyway), the remaining people would experience the changed conditions and in fairness to them some additional moral value conceivably should be assigned”

    Varies. Fairness is a moral good but obviously not the whole of it. We would like to end poverty; out of fairness some sacrifices on the part of the well-off could be justified (being careful of fairness, though), but bringing everyone down to the same level of poverty would be of little good. There is poverty today, war today, diseases that are hard to treat today; people suffer and die. It would be absurd to not advance politically, economically, and technologically, in the name of fairness.

    However, future generations will benifit from work done now and before – through economic investments and scientific/technological/cultural progress, etc. It would be allowable for the people of today and near future to benifit with some expense to future generations if it is more than balanced by benificial inheritance. Of course, not all is give and take; some of what we do for ourselves benifits the future and vice versa. And the cost of climate change (and other messes) could not only subtract from the net inheritance but also degrade the part that is or would be good (as has been suggested above by others).

    And inflation adjusted G(D/N)P and/or accumulated property value per capita wouldn’t probably be linearly proportional to quality of life/standard of living – in which case, economic growth would reduce the impact to standard of living of the same economic loss from climate change, although it wouldn’t be the same economic loss because of the economic growth, etc.

    This does suggest that a portion of emissions tax revenue could go to cuts in other taxes and equal per capita rebate as well as general long-term economic investments (whether in green power or efficiency, adaptation, or something not so directly related to climate, like medical advances) could be justified on the basis of paying back the future for the incurred climate change costs. This suggests that the net imposed price signal as defined by some form of emissions tax + efficiency and clean energy subsidy could be greater than the actual public cost of the emissions, the remainder justified by the future benifits that would help make up for the adaptation costs and losses (and also justified by the utility of public planning – such as helping new industries grow to the point where they can realize mass market advantages, overcoming habitual practices in building, etc.)

  29. 329
    Patrick 027 says:

    PS on the societal level uncertainty being less than individual uncertainty – we don’t know future individuals exactly (future versions of ourselves as well as new people yet to be determined), but the mix of individuals may be characterized in a more predictable way – and we know we have limited options to slow and halt population growth, although we should be doing what we can within moral guidelines (war, famine, disease, totalitarian stuff – is not a valid strategy), etc.