Thanks for the useful feedback and responses to this question everyone. Its not an area I have expertise in, so the feedback has been exceptionally useful, Kind Regards Gideon
On Thu, 28 Jul 2022 at 15:09, Douglas MacMartin <dgm...@cornell.edu> wrote: > I agree that the sign of the effect is unclear in addition to the > magnitude, that is, nuclear winter + termination is “better” at first than > nuclear winter alone, but “worse” afterwards if it is impossible to > restart; that of course is all contingent on how bad the nuclear winter is, > how much cooling is being offset, and your beliefs about how the use of SRM > does or doesn’t affect mitigation (that is, the circumstances in which > termination materially affects outcomes are those in which SRM is being > used to offset significant warming – so from a risk perspective, if the > counterfactual is that much warmer world, or the counterfactual a world > that had more mitigation, is essential). > > > > I agree that as researchers we should try to inform decisions, and hence > risks, and be responsive to stakeholder concerns. In this case, I think > the **much** bigger influence of SRM on nuclear winter comes from whether > it increases or decreases the risks of nuclear war, and what we can do in > terms of governance to affect that… > > > > *From:* Gideon Futerman <ggfuter...@gmail.com> > *Sent:* Wednesday, July 27, 2022 6:10 PM > *To:* Douglas MacMartin <dgm...@cornell.edu> > *Cc:* gdebrou...@gmail.com; Daniele Visioni <daniele.visi...@gmail.com>; > geoengineering <geoengineering@googlegroups.com> > *Subject:* Re: [geo] Nuclear Winter and SRM (including termination shock) > > > > I think this is going to get into more general philosophy/ethics around > Existential Risks, Longtermism and Global Catastrophic Risks, which whilst > interesting and useful, probably a bit orthogonal to what people are > turning to the geoengineering google group for. But basically, a difference > between 6 billion and say 6.1 billion or 6.5 billion is firstly important > from the perspective of deaths: that's still 100 million people. Secondly, > climatic effects, excess deaths on top of the nuclear winter (or reduced > severity!) etc are potentially relevant for whether it will "only" kill 6 > billion and whether it will lead to irrecoverable (not merely awful) > societal collapse, which from various longtermist perspectives is very bad. > Given how hard it would be to recover anyway, a "double catastrophe" could > make recovery much harder distinguish between a Global Catastrophic Risk > and an existential risk, which from various philosophical viewpoints is > very important. > > Thus, such a question ie whether SRM might increase/decrease the > likelihood of a global catastrophic risk being converted to an existential > risk (due to this Latent Risk of termination shock we have been discussing) > is of serious interest to many people, including potentially major funders > who are potentially interested in investing in SRM research. In that sense, > this impacts some potentially very important decisions for the future of > our field, and the distinction between 6 billion and say 6.5 billion, or > even if it just makes societal recovery 10% less likely to happen, it may > be absolutely vital. I am happy to explain this in more depth if people > need, although what I was really wanting to ask the list for was > fundamentally a question of physical science to try and answer this > application. > > Even if none of this has convinced you of the moral importance of it, the > question I was asking was fundamentally a physical one, responding to a > scientific assumption in Baum et al 2013 that I thought seemed potentially > unsound (that under nuclear war termination shock would lead to a double > catastrophe and not a slight softening of the first catastrophe). Given > that paper is one of only a handful papers published in this intersection > between SRM and Global Catastrophic Risk studies, such a claim is, even > from a physical/empirical rather than moral viewpoint, important to test. > Hence why I have posed this question. > > > > > > On Wed, 27 Jul 2022 at 19:59, Douglas MacMartin <dgm...@cornell.edu> > wrote: > > All of the above, with qualifiers… yes the climatic response would be > different, but personally I think 6B dead is so bad that whether it’s 6.01 > or 6.1 or 6.5 isn’t something that I feel matters particularly (nor do I > think it is particularly answerable). What decisions would depend on the > answer to that question? > > > > *From:* Gideon Futerman <ggfuter...@gmail.com> > *Sent:* Wednesday, July 27, 2022 1:31 PM > *To:* Douglas MacMartin <dgm...@cornell.edu> > *Cc:* gdebrou...@gmail.com; Daniele Visioni <daniele.visi...@gmail.com>; > geoengineering <geoengineering@googlegroups.com> > *Subject:* Re: [geo] Nuclear Winter and SRM (including termination shock) > > > > Hi Doug, > > Apologies for misinterpreting. Its a statement like this that I have been > looking for. > > When you suggest it isn't appreciably worse, is that a suggestion that > either: > > - The death toll/ the ability for society to recover would be no different > given the double catastrophe than the single catastrophe > > - The climatic response to the double catastrophe is no different than the > single catastrophe > > - The difference in death toll may be, say (and these are made up numbers) > 6 billion vs 6.01 billion > > Thank you so much for the clarification > > Best > > Gideon > > > > On Wed, 27 Jul 2022 at 17:58, Douglas MacMartin <dgm...@cornell.edu> > wrote: > > Of course there are more minor conflicts possible with less severe > outcomes… though if it’s a regional war that doesn’t itself end > civilization, I don’t see why one couldn’t restart SRM in a year or two if > desired. > > > > Gideon, you write: “I understand why there is aversion to me exploring > such risks;” I think you misunderstand everyone’s response here. It > isn’t an aversion to exploring them, nor a belief that we don’t need to > look at extreme but less likely scenarios, but rather, that this specific > risk doesn’t seem to many of us like there’s anything that needs to be > explored. That is, my view, and I think others, is that any nuclear war > severe enough to result in losing the ability to even restart SRM is so > severe that the nuclear war + termination isn’t appreciably worse than the > nuclear war itself. > > > > I 100% agree with the need to think through low probability but high > impact possibilities. > > > > d > > > > *From:* geoengineering@googlegroups.com <geoengineering@googlegroups.com> *On > Behalf Of *Gilles de Brouwer > *Sent:* Tuesday, July 26, 2022 11:11 PM > *To:* ggfuter...@gmail.com > *Cc:* Daniele Visioni <daniele.visi...@gmail.com>; geoengineering < > geoengineering@googlegroups.com> > *Subject:* Re: [geo] Nuclear Winter and SRM (including termination shock) > > > > FYI Updated nuclear winter analysis is so much worse than SAI that it's > pointless to consider. > > > > *Nuclear winter revisited with a modern climate model and current nuclear > arsenals: Still catastrophic consequences* > Alan Robock,1 Luke Oman,1,2 and Georgiy L. Stenchikov1 > Received 8 November 2006; revised 2 April 2007; accepted 27 April 2007; > published 6 July 2007 > > https://climate.envsci.rutgers.edu/pdf/RobockNW2006JD008235.pdf > > > Gilles de Brouwer > > > > > > On Tue, Jul 26, 2022 at 5:50 PM Gideon Futerman <ggfuter...@gmail.com> > wrote: > > Apologies, you are correct, I was using the ECS values from AR5 and forgot > it had reduced with AR6. I was also getting my range vs values mixed up. > > Nonetheless, a similar point still broadly stands- the ipcc suggests with > only medium confidence that it is "very likely" that ECS is between 2K and > 5K (not 6K as I had previously stated), putting a warming of anything above > 5K therefore at between 0-5% probability with medium confidence. > > Whilst I appreciate the desire to focus on the median ECS, I think it is > nonetheless important to consider the more extreme, fat tailed risks. Not > because these will happen or are likely to happen, but because in general > such worse case scenario, low probability high impact scenarios are > neglected. > > This is the same reason I care about SRM in concert with a nuclear war. > Not because I want to overplay how important SRM is under such a scenario, > but merely want to explore the worse case scenarios. I don’t think > (certainly hope not) that any of the scenarios the RESILIENCER Project > explores are likely, certainly none are the median scenarios. Rather, they > are those scenarios in the fat tails of the possible risks. > > I understand why there is aversion to me exploring such risks; I would > hate people to think that I am claiming the research community at large > should start focusing on such risks (which would be foolish). Nonetheless, > it seems odd to not at least some degree look at these more extreme, much > less likely, scenarios. > > > > On Tue, 26 Jul 2022, 22:33 Daniele Visioni, <daniele.visi...@gmail.com> > wrote: > > Dear Gideon, > not to pile on but I feel like this should be corrected: none of the most > current IPCC projections say that 550ppm have a 10% chance of leaving us > with 6K of warming. > > Even the most high sensitivity models in CMIP6 only show a ECS of, at > most, 5 per doubling of CO₂ (so 560), but the best estimate is still around > 3K given a whole range of approaches to estimate it. > > For more relevant IPCC scenarios during this century, given transient > sensitivity and more, scenarios that lead to 550ppm (considering also other > GHG, LUC, aerosols) like SSP2-4.5 have a median warming of a bit less than > 3K. > > How can surely say the IPCC is wrong and climate models are wrong, of > course. > > > > (Ça vas sans dire, I’m not trying to downplay climate change! But being > precise helps having better discussions :) ) > > > > > > On 26 Jul 2022, at 17:20, Gideon Futerman <ggfuter...@gmail.com> wrote: > > Dear Dr Robock, > > Whilst I would admit that 3K of cooling by SRM is unlikely, it is > certainly not out of the range of possibility. Given CO2 concentrations of > 550PPM have a 10% chance of leaving us with 6K of warming (and that > certainly doesn't seem to be an unreasonable amount of emissions given > mitigation trajectories), it certainly doesn't seem like there is a less > than 10% probability of a given deployment scheme being 3K of forcing. > > Secondly, why care about this if there is a nuclear war. Maybe you are > correct, and there is no worry. But if you care about post-nuclear war > societal recovery, it may be important to know whether SRM-driven > termination shock makes that more or less likely, or is entirely > negligible. Of course, the primary worry here is avoid the initial > catastrophe (nuclear war). Nonetheless, the question of whether SRM > termination shock under nuclear war has any effect (even if only 10% of the > magnitude of the effects of the nuclear war) is significant. > > I am trying to look at low probability, heavy tailed risks of SRM, > including how it interacts with other risks. This is why I want to look at > the (relatively unlikely) scenario which I have laid out. > > And apologies for the spelling mistake, spelling is certainly not my > strong suit! > > Kind Regards > > Gideon Futerman > > He/Him > > www.resiliencer.org > > On Tuesday, 26 July 2022 at 16:05:48 UTC+1 Alan Robock wrote: > > Dear Gideon, > > It is spelled "negligible." And nobody is suggesting enough SAI to > produce 3K cooling, because that means there has been no mitigation. > > A nuclear war could kill billions of people from starvation, and would > collapse civilization, surely reducing greenhouse gas emissions. Why would > you even worry about global warming and geoengineering then? That's why I > say your are comparing two things that are of completely different scales. > > > > > Alan Robock > > Alan Robock, Distinguished Professor > Department of Environmental Sciences Phone: +1-848-932-5751 > <(848)%20932-5751> > Rutgers University E-mail: > rob...@envsci.rutgers.edu > 14 College Farm Road http://people.envsci.rutgers.edu/robock > New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock > > On 7/26/2022 10:59 AM, Gideon Futerman wrote: > > Dear Alan Robock, > > When you say overwhelm, is the suggestion here that the increase in > radiative forcing from the termination of aerosol injection would be > entirely negligable compared to the nuclear winter scenario? > > If SAI were masking 3K of warming, and you got a nuclear winter driven > cooling of say 7K, surely the impact of the termination of SAI would not be > negligable, even if it would be significantly less than the cooling of > nuclear winter (ie you still get a nuclear winter)? I am trying to work out > if the "double catastrophe" as Baum calls it actually applies in the > nuclear winter scenario. So the question of whether the removal of the > contribution of SAI to radiative forcing (by termination) makes the nuclear > winter (and the resulting warming afterwards) worse, less bad or is > entirely negligable is important. > > Moreover might sunlight removal effects be important in the short term, > particularly if it were a relatively high SAI radiative forcing and > (relatively) minor nuclear winter (say about 6K of cooling)? Given up to > 50% of sulfate aerosols remain in the stratosphere up to 8 months after > termination, would the added impact of the sulfate aerosols on top of the > significantly more soot aerosols have an effect of sunlight available for > photosynthesis, so increase impact on food production in the early days of > the nuclear winter? Or would this simply be negligable in the face of the > radiation reduction from even a relatively minor nuclear winter? > > Kind Regards > > Gideon > > > > On Tuesday, 26 July 2022 at 15:20:44 UTC+1 Alan Robock wrote: > > Dear Gideon, > > A nuclear war would be orders of magnitude worse than any impacts of SAI > or termination. Soot from fires ignited by nuclear attacks on cities and > industrial areas would last for many years, and would overwhelm any impacts > from shorter lived sulfate aerosols. Of course the impacts depend on how > much soot, but a war between the US and Russia could produce a nuclear > winter. For more information on our work and the consequences of nuclear > war, please visit http://climate.envsci.rutgers.edu/nuclear/ > > > Alan Robock > > Alan Robock, Distinguished Professor > Department of Environmental Sciences Phone: +1-848-932-5751 > <(848)%20932-5751> > Rutgers University E-mail: > rob...@envsci.rutgers.edu > 14 College Farm Road http://people.envsci.rutgers.edu/robock > New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock > > On 7/26/2022 10:03 AM, Gideon Futerman wrote: > > As part of the RESILIENCER Project, we are looking at low probability high > impact events and their relation to SRM. One important worry in this > regards becomes termination shock, most importantly what Baum (2013) calls > a "Double Catastrophe" where a global societal collapse caused by one > catastrophe then causes termination shock, another catastrophe, which may > convert the civilisational collapse into a risk of extinction. > > > > One such initial catastrophe may be nuclear war. Thus, the combination of > SRM and nuclear war may be a significant worry. As such, I am posing the > question to the google group: what would happen if SRM (either > stratospheric or tropospheric- or space based if you want to go there) was > terminated due to a nuclear war? What sort of effects would you expect to > see? Would the combination worsen the effects of nuclear war or help > ameliorate them? How would this differ between SRM types? > > > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineerin...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/8d0d8c0a-0f0d-440c-9bb5-f8641560e4a0n%40googlegroups.com > <https://groups.google.com/d/msgid/geoengineering/8d0d8c0a-0f0d-440c-9bb5-f8641560e4a0n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineerin...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/b541017e-b87b-4492-b840-91e39d0b0601n%40googlegroups.com > <https://groups.google.com/d/msgid/geoengineering/b541017e-b87b-4492-b840-91e39d0b0601n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/419bee77-0d9a-416a-9b38-5fc6f584ba3cn%40googlegroups.com > <https://groups.google.com/d/msgid/geoengineering/419bee77-0d9a-416a-9b38-5fc6f584ba3cn%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAK73TM%2BA0dvOcYEOQd1_CKFE6YM1KZjTSQUo2HvZqhvRY4HMUw%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CAK73TM%2BA0dvOcYEOQd1_CKFE6YM1KZjTSQUo2HvZqhvRY4HMUw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAGQ2tEqL6%2BWSDBBQZnGjVwgPLz81mW7-hMjuRih_e6u9naRGcw%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CAGQ2tEqL6%2BWSDBBQZnGjVwgPLz81mW7-hMjuRih_e6u9naRGcw%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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