Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

It would be good to know if something about my calculations here are 
fundamentally wrong. I am no aerosol expert by any margins, and as seen, my 
model is pretty much the most simple possible thing that I could make on 
this, but it does seem to give an indication against the "double 
catastrophe" thesis. Please let me know if I am wrong on this

On Monday, 15 August 2022 at 16:15:09 UTC+1 Gideon Futerman wrote:

> I've just tried running some really simple equations to look at forcing, 
> so I thought I would share my back of the envelope calculations and see 
> what you all think.
> So I tried to calculate what would happen to forcing in a 5Tg of soot 
> released (likely due to a regional nuclear war) combined with a termination 
> shock, possibly due to cascading impacts of the nuclear war on the global 
> economy, for example. I used a value of -15Wm^-2 for the maximum forcing 
> from the soot, and a e-folding time of 4.6 years [Robock  et al 2007]. I 
> then used a solar geoengineering forcing of -4Wm^-2 (the maximum forcing 
> from Pinatubo) and an e-folding time of 1 year.
> I treated the forcing relative to the nongeoengineered world prior to the 
> nuclear winter, so treated that as 0Wm^-2 and the forcing of the 
> geoengineered world before the nuclear winter at 4Wm^-2. The soot was 
> injected at the end of year 1. Immediately after soot injection at the end 
> of year 1, the forcing(geo) is -19Wm^-2 and the forcing(nongeo) is 
> -15Wm^-2. At the end of year 2, so 1 year after the soot injection, the 
> forcing (geo) is 14Wm^-2 and the forcing(nongeo) is 12Wm^-2, so the delta 
> for the forcing(geo) relative to their initial values is 16.7% less than 
> the delta forcing (nongeo).
> The two equations I used  for year 1 were as follows:
> y=0 (nongeo)
> y=-4 (geo)
> The two equations I used for the end of year 1 onwards were
> y=-15e ^(-1/4.6 * (t-1)) [nongeo]
> y=-15e^(-1/4.6 * (t-1)) -3e^(-(t-1)) [geo]
>
> The graph I got is here (https://www.desmos.com/calculator/duz3tlpkky)
> It seems to me for a relatively small scale nuclear winter and  a 
> moderately large SRM forcing that the forcing impacts of termination shock 
> are not negligable. This obviously doesn't necessarily translate to climate 
> respone
>
> I did a few others for other SRM and nuclear war scenarios, which I can 
> send through if people were interested.
> Obviously these calculations are massively simplified, back of the 
> envelope calculations, but I would nonetheless be interested in peoples 
> thoughts on it. Apologies if I have messed up somewhere
> Kind Regards
> Gideon
>
> On Sunday, 7 August 2022 at 01:36:17 UTC+1 Russell Seitz wrote:
>
>> I'm  surprised Alan should neglect to cite studies other than his own, as 
>>  climate responses to carbon aerosols in the atmosphere vary greatly. The 
>> recent literature is illustrative- a growing  concern is the impact of 
>> black carbon from satellite and spacecraft launches, which may warm the 
>> upper atmosphere rather than cool it:
>>
>> Journal of Geophysical Research: Atmospheres 
>>   1June2022
>>
>> The Climate and Ozone Impacts of Black Carbon Emissions From Global 
>> Rocket Launches
>> Christopher M Maloney 
>> 
>> , Robert W Portmann 
>> 
>> , Martin N Ross 
>> 
>> , Karen H Rosenlof 
>> 
>>  
>> https://doi.org/10.1029/2021JD036373
>>
>> Aerosol emissions from spaceflight activities play a small but increasing 
>> role in the background stratospheric aerosol population. Rockets used by 
>> the global launch industry emit black carbon (BC) particles directly into 
>> the stratosphere where they accumulate, absorb solar radiation, and warm 
>> the surrounding air. We model the chemical and dynamical response of the 
>> atmosphere to northern mid-latitude rocket BC emissions. We initially 
>> examine emissions at a rate of 10 Gg per year, which is an order of 
>> magnitude larger than current emissions, but consistent with extrapolations 
>> of space traffic growth several decades into the future. We also perform 
>> runs at 30 and 100 Gg per year in order to better delineate the 
>> atmosphere's response to rocket BC emissions. We show that a 10 Gg/yr 
>> rocket BC emission increases stratospheric temperatures by as much as 1.5 K 
>> in the stratosphere. Changes in global circulation also occur. For example, 
>> the annual subtropical jet wind speeds slow down by as much as 5 m/s, while 
>> a 10%–20% weakening of the overturning circulation occurs in the northern 
>> hemisphere during multiple seasons. Warming temperatures lead to a 

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

I've just tried running some really simple equations to look at forcing, so 
I thought I would share my back of the envelope calculations and see what 
you all think.
So I tried to calculate what would happen to forcing in a 5Tg of soot 
released (likely due to a regional nuclear war) combined with a termination 
shock, possibly due to cascading impacts of the nuclear war on the global 
economy, for example. I used a value of -15Wm^-2 for the maximum forcing 
from the soot, and a e-folding time of 4.6 years [Robock  et al 2007]. I 
then used a solar geoengineering forcing of -4Wm^-2 (the maximum forcing 
from Pinatubo) and an e-folding time of 1 year.
I treated the forcing relative to the nongeoengineered world prior to the 
nuclear winter, so treated that as 0Wm^-2 and the forcing of the 
geoengineered world before the nuclear winter at 4Wm^-2. The soot was 
injected at the end of year 1. Immediately after soot injection at the end 
of year 1, the forcing(geo) is -19Wm^-2 and the forcing(nongeo) is 
-15Wm^-2. At the end of year 2, so 1 year after the soot injection, the 
forcing (geo) is 14Wm^-2 and the forcing(nongeo) is 12Wm^-2, so the delta 
for the forcing(geo) relative to their initial values is 16.7% less than 
the delta forcing (nongeo).
The two equations I used  for year 1 were as follows:
y=0 (nongeo)
y=-4 (geo)
The two equations I used for the end of year 1 onwards were
y=-15e ^(-1/4.6 * (t-1)) [nongeo]
y=-15e^(-1/4.6 * (t-1)) -3e^(-(t-1)) [geo]

The graph I got is here (https://www.desmos.com/calculator/duz3tlpkky)
It seems to me for a relatively small scale nuclear winter and  a 
moderately large SRM forcing that the forcing impacts of termination shock 
are not negligable. This obviously doesn't necessarily translate to climate 
respone

I did a few others for other SRM and nuclear war scenarios, which I can 
send through if people were interested.
Obviously these calculations are massively simplified, back of the envelope 
calculations, but I would nonetheless be interested in peoples thoughts on 
it. Apologies if I have messed up somewhere
Kind Regards
Gideon

On Sunday, 7 August 2022 at 01:36:17 UTC+1 Russell Seitz wrote:

> I'm  surprised Alan should neglect to cite studies other than his own, as 
>  climate responses to carbon aerosols in the atmosphere vary greatly. The 
> recent literature is illustrative- a growing  concern is the impact of 
> black carbon from satellite and spacecraft launches, which may warm the 
> upper atmosphere rather than cool it:
>
> Journal of Geophysical Research: Atmospheres 
>   1June2022
>
> The Climate and Ozone Impacts of Black Carbon Emissions From Global Rocket 
> Launches
> Christopher M Maloney 
> 
> , Robert W Portmann 
> 
> , Martin N Ross 
> 
> , Karen H Rosenlof 
> 
>  
> https://doi.org/10.1029/2021JD036373
>
> Aerosol emissions from spaceflight activities play a small but increasing 
> role in the background stratospheric aerosol population. Rockets used by 
> the global launch industry emit black carbon (BC) particles directly into 
> the stratosphere where they accumulate, absorb solar radiation, and warm 
> the surrounding air. We model the chemical and dynamical response of the 
> atmosphere to northern mid-latitude rocket BC emissions. We initially 
> examine emissions at a rate of 10 Gg per year, which is an order of 
> magnitude larger than current emissions, but consistent with extrapolations 
> of space traffic growth several decades into the future. We also perform 
> runs at 30 and 100 Gg per year in order to better delineate the 
> atmosphere's response to rocket BC emissions. We show that a 10 Gg/yr 
> rocket BC emission increases stratospheric temperatures by as much as 1.5 K 
> in the stratosphere. Changes in global circulation also occur. For example, 
> the annual subtropical jet wind speeds slow down by as much as 5 m/s, while 
> a 10%–20% weakening of the overturning circulation occurs in the northern 
> hemisphere during multiple seasons. Warming temperatures lead to a ozone 
> reduction in the northern hemisphere by as much as 16 DU in some months. 
> The climate response increases in a near linear fashion when looking at 
> larger 30 and 100 Gg emission scenarios. Comparing the amplitude of the 
> atmospheric response using different emission rates provides insight into 
> stratospheric adjustment and feedback mechanisms. Our results show that the 
> stratosphere is sensitive to relatively modest BC injections.
>
> On Tuesday, July 26, 2022 at 10:20:44 AM UTC-4 Alan Robock wrote:
>
>> Dear Gid

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Russell Seitz]

I'm  surprised Alan should neglect to cite studies other than his own, as 
 climate responses to carbon aerosols in the atmosphere vary greatly. The 
recent literature is illustrative- a growing  concern is the impact of 
black carbon from satellite and spacecraft launches, which may warm the 
upper atmosphere rather than cool it:

Journal of Geophysical Research: Atmospheres 
  1June2022

The Climate and Ozone Impacts of Black Carbon Emissions From Global Rocket 
Launches
Christopher M Maloney 

, Robert W Portmann 

, Martin N Ross 

, Karen H Rosenlof 

 
https://doi.org/10.1029/2021JD036373

Aerosol emissions from spaceflight activities play a small but increasing 
role in the background stratospheric aerosol population. Rockets used by 
the global launch industry emit black carbon (BC) particles directly into 
the stratosphere where they accumulate, absorb solar radiation, and warm 
the surrounding air. We model the chemical and dynamical response of the 
atmosphere to northern mid-latitude rocket BC emissions. We initially 
examine emissions at a rate of 10 Gg per year, which is an order of 
magnitude larger than current emissions, but consistent with extrapolations 
of space traffic growth several decades into the future. We also perform 
runs at 30 and 100 Gg per year in order to better delineate the 
atmosphere's response to rocket BC emissions. We show that a 10 Gg/yr 
rocket BC emission increases stratospheric temperatures by as much as 1.5 K 
in the stratosphere. Changes in global circulation also occur. For example, 
the annual subtropical jet wind speeds slow down by as much as 5 m/s, while 
a 10%–20% weakening of the overturning circulation occurs in the northern 
hemisphere during multiple seasons. Warming temperatures lead to a ozone 
reduction in the northern hemisphere by as much as 16 DU in some months. 
The climate response increases in a near linear fashion when looking at 
larger 30 and 100 Gg emission scenarios. Comparing the amplitude of the 
atmospheric response using different emission rates provides insight into 
stratospheric adjustment and feedback mechanisms. Our results show that the 
stratosphere is sensitive to relatively modest BC injections.

On Tuesday, July 26, 2022 at 10:20:44 AM UTC-4 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 UniversityE-mail: 
> rob...@envsci.rutgers.edu
> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>
> [image: Signature] 
>
>
> 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/

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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  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 
> *Sent:* Wednesday, July 27, 2022 6:10 PM
> *To:* Douglas MacMartin 
> *Cc:* gdebrou...@gmail.com; Daniele Visioni ;
> geoengineering 
> *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 
> 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 
> *Sent:* Wednesday, July 27, 2022 1:31 PM
> *To:* Douglas MacMartin 
> *Cc:* gdebrou...@gmail.com; Daniele Visioni ;
> geoengineering 
> *Subject:* Re: [geo] Nuclear Winter and SRM (including termination shock)
>
>
>
> Hi Doug,
>
> A

RE: [geo] Nuclear Winter and SRM (including termination shock)

[Douglas MacMartin]

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 
Sent: Wednesday, July 27, 2022 6:10 PM
To: Douglas MacMartin 
Cc: gdebrou...@gmail.com; Daniele Visioni ; 
geoengineering 
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 
mailto: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 mailto:ggfuter...@gmail.com>>
Sent: Wednesday, July 27, 2022 1:31 PM
To: Douglas MacMartin mailto:dgm...@cornell.edu>>
Cc: gdebrou...@gmail.com<mailto:gdebrou...@gmail.com>; Daniele Visioni 
mailto:daniele.visi...@gmail.com>>; geoengineering 
mailto: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

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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  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 
> *Sent:* Wednesday, July 27, 2022 1:31 PM
> *To:* Douglas MacMartin 
> *Cc:* gdebrou...@gmail.com; Daniele Visioni ;
> geoengineering 
> *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 
> 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  *On
> Behalf Of *Gilles de Brouwer

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Andrew Lockley]

If you consider the residual human population, the difference is huge.
Losing 0.1 of the last billion people alive would be losing 10pc of the
entire global population. Further, that might not be evenly distributed.
For example, it might mean the death of all - or almost all - of the
surviving people in the Indian subcontinent. Such concentrated additional
deaths would be a genetic and cultural catastrophe for the remnants of the
human race.

I think it would be complacent to dismiss Gideon's concerns. Much of
interest may be revealed by modelling such clustered catastrophes. Some of
the results may give us answers to questions not yet asked.

In general, I think considering stacked disasters is wise. We currently
have several linked minor disasters - a regional war, a fuel price shock
and the beginning of a global famine. A small nuclear war on top is
unlikely, but it would be a brave man to argue it was impossible. While
these issues have a common cause, they aren't the same thing.

A

On Wed, 27 Jul 2022, 19:59 Douglas MacMartin,  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 
> *Sent:* Wednesday, July 27, 2022 1:31 PM
> *To:* Douglas MacMartin 
> *Cc:* gdebrou...@gmail.com; Daniele Visioni ;
> geoengineering 
> *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 
> 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  *On
> Behalf Of *Gilles de Brouwer
> *Sent:* Tuesday, July 26, 2022 11:11 PM
> *To:* ggfuter...@gmail.com
> *Cc:* Daniele Visioni ; 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 
> 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

RE: [geo] Nuclear Winter and SRM (including termination shock)

[Douglas MacMartin]

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 
Sent: Wednesday, July 27, 2022 1:31 PM
To: Douglas MacMartin 
Cc: gdebrou...@gmail.com; Daniele Visioni ; 
geoengineering 
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 
mailto: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<mailto:geoengineering@googlegroups.com> 
mailto:geoengineering@googlegroups.com>> On 
Behalf Of Gilles de Brouwer
Sent: Tuesday, July 26, 2022 11:11 PM
To: ggfuter...@gmail.com<mailto:ggfuter...@gmail.com>
Cc: Daniele Visioni 
mailto:daniele.visi...@gmail.com>>; geoengineering 
mailto: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 
mailto: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, 
mailto: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 C

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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  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  *On
> Behalf Of *Gilles de Brouwer
> *Sent:* Tuesday, July 26, 2022 11:11 PM
> *To:* ggfuter...@gmail.com
> *Cc:* Daniele Visioni ; 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 
> 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, 
> 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.
>

RE: [geo] Nuclear Winter and SRM (including termination shock)

[Douglas MacMartin]

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  On 
Behalf Of Gilles de Brouwer
Sent: Tuesday, July 26, 2022 11:11 PM
To: ggfuter...@gmail.com
Cc: Daniele Visioni ; geoengineering 

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 
mailto: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, 
mailto: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 
mailto: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 ini

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Andrew Lockley]

To address nuclear winter, consider this paper, Daniel Heyen, Joshua
Horton, and Juan Moreno-Cruz. 3/20/2019. “Strategic implications of
counter-geoengineering: Clash or cooperation?” Journal of Environmental
Economics and Management, 95, Pp. 153-177.

This offers a possible way out. Equipment to release short lived climate
forces could be ruggedised, making it largely impervious to nuclear war -
for example, by releasing gases into deep caves, which slowly find their
way into the atmosphere.

Similarly, as the nuclear winter ends and termination shock becomes an
issue (a nuclear summer), consider this paper.

An approach to sulfate geoengineering with surface emissions of carbonyl
sulfide
Ilaria Quaglia et al.
https://acp.copernicus.org/articles/22/5757/2022/acp-22-5757-2022-assets.html
This offers very similar technology for warming, which could be again set
up in deep caves, impervious to nuclear weapons.

Such systems could be designed with a "dead man's handle" control system -
in that they automatically release without intervention, either if not
manually reset or if a pressure drop or electromagnetic / seismic pulse is
detected, indicating a nuclear strike.

A



On Wed, 27 Jul 2022, 12:44 Gideon Futerman,  wrote:

> Hi all,
> I think I ought to clarify what I am trying to do and repose the question,
> as well as respond to all the replies.
> What I am attempting to do is this: Under low probability scenarios of
> nuclear war with high SRM burden (maybe due to a large warming, either
> because of high emissions or high ECS and TCR, either being far in excess
> of either the most likely scenarios or of the median values), would the
> termination "shock" have any effect? Not just would it be dwarfed by the
> effect of nuclear war, but would it truly be negligible in comparison? If
> not, what would the effect be?
> Why do I care about this; after all, a global nuclear war capable of
> producing civilizational collapse enough to cause SRM termination would
> kill billions, and as Mike MacKraken suggests, would massively change
> society (what I am terming "collapse")?
> - From many philosophical worldviews, it is important to know if such
> collapse would be permanent or lead to human extinction, or whether it is
> recoverable. These obviously exist on a spectrum, and thus whether
> something like SRM contributes to it being easier/harder for recovery from
> collapse is really important.
> - Whilst it is true that, in terms of the arguments you have been making,
> nuclear war is the real and most important problem, it is still important
> to know if large scale termination shock contributes in any meaningful way
> to either slightly increasing or slightly decreasing the damages from the
> nuclear winter. Such relatively small changes (a single order of magnitude
> lower lets say) may be important in terms of whether a collapse is
> recoverable (note the word may, I would be happy to hear evidence to the
> contrary)
>
> Now onto responses to the points raised:
> In response to Alan and Gilles:
> In Alan's paper that Gilles cites, the temperature anomaly is less than
> 8K, and in Coupe et al 2019 which Alan cites on his website (as one of many
> excellent papers that he has co-authored), the temperature anomaly is of
> -10K. Of course, the impacts are not limited to cooling (nor the impacts of
> nuclear war limited to nuclear winter). Nonetheless, and please do tell me
> if I am missing something key here, it doesn't seem that the temperature
> anomaly that SRM termination would cause (be it +1K or +3K or others) would
> be entirely negligible. Of course, it would be dwarfed by the impact of
> nuclear war, which will cause the vast majority of the damage, causes the
> first catastrophe that causes civilizational collapse, and causes the
> deaths of billions. Nonetheless, I struggle to see how this by itself makes
> the impact of SRM induced forcing negligible. For instance, if, as Doug
> MacMartin is suggesting, SRM termination reduces the delta T from nuclear
> winter, even by 1K, surely that's somewhat significant. Please correct me
> if such an assessment is wrong. Similarly, if SRM makes the whole scenario
> worse, in the way that Seth Baum suggests in Baum (2013), then that is also
> significant. Even if it is small compared to the impact of nuclear winter,
> none of these plausible impacts seem negligible to me, even if we were only
> doing 1K of cooling with SRM (even less so if doing 3K of cooling). If I
> care about increasing the chance the civilizational collapse isn't
> permanent/ doesn't result in human extinction by any amount (be it 1 or
> 10%), then these questions seem significant.
>
> In response to Renaud and Andrew
> The catastrophe proposed in this scenario is a global catastrophe that
> essentially collapses civilisation, reducing the capacity of human
> organisation to such a degree that sustaining SRM would simply not be
> possible. This is the reason I somewhat doubt that a more 

RE: [geo] Nuclear Winter and SRM (including termination shock)

[kevin lister]

Dear Gideon,  I think that you are grabbing the wrong end of the stick. The problem is that once nations have nuclear arsenals and are engaged in nuclear weapons races which require competing military industrial complexes and permanently expanding economies to fund these then there is an unstoppable commitment to increasing fossil fuel consumption. Ironically, the worse that climate change gets, the more nations will seek protection under their nuclear umbrellas and the more nations will resort to conventional war.  Thus nuclear weapons and the arms races they drive become the biggest cause of climate change and the resulting climate change lowers the threshold for nuclear war, as Renaud points out below.  Once we have nuclear war, as everyone has pointed out debates about SRM are irrelevant. The question now is how do we link security and climate change commitments in a world where competing nations have all adopted first strike responses with nuclear weapons. My view is that unless we have a modern day Baruch Agreement to do this will not succeed and this is not even on any agenda.  My past calculations using game theory and which I have supported with modelling indicate the chance of success without such an agreement is 1E-63. That is considerably less than finding a single atom on the plant in a random selection. Under this interpretation, commitments to high carbon emissions and eventual nuclear war are extremely high probability outcomes with current political system. Kevin   Sent from Mail for Windows From: Gideon FutermanSent: 27 July 2022 12:44To: geoengineeringSubject: Re: [geo] Nuclear Winter and SRM (including termination shock) Hi all,I think I ought to clarify what I am trying to do and repose the question, as well as respond to all the replies.What I am attempting to do is this: Under low probability scenarios of nuclear war with high SRM burden (maybe due to a large warming, either because of high emissions or high ECS and TCR, either being far in excess of either the most likely scenarios or of the median values), would the termination "shock" have any effect? Not just would it be dwarfed by the effect of nuclear war, but would it truly be negligible in comparison? If not, what would the effect be?Why do I care about this; after all, a global nuclear war capable of producing civilizational collapse enough to cause SRM termination would kill billions, and as Mike MacKraken suggests, would massively change society (what I am terming "collapse")? - From many philosophical worldviews, it is important to know if such collapse would be permanent or lead to human extinction, or whether it is recoverable. These obviously exist on a spectrum, and thus whether something like SRM contributes to it being easier/harder for recovery from collapse is really important.- Whilst it is true that, in terms of the arguments you have been making, nuclear war is the real and most important problem, it is still important to know if large scale termination shock contributes in any meaningful way to either slightly increasing or slightly decreasing the damages from the nuclear winter. Such relatively small changes (a single order of magnitude lower lets say) may be important in terms of whether a collapse is recoverable (note the word may, I would be happy to hear evidence to the contrary) Now onto responses to the points raised:In response to Alan and Gilles:In Alan's paper that Gilles cites, the temperature anomaly is less than 8K, and in Coupe et al 2019 which Alan cites on his website (as one of many excellent papers that he has co-authored), the temperature anomaly is of -10K. Of course, the impacts are not limited to cooling (nor the impacts of nuclear war limited to nuclear winter). Nonetheless, and please do tell me if I am missing something key here, it doesn't seem that the temperature anomaly that SRM termination would cause (be it +1K or +3K or others) would be entirely negligible. Of course, it would be dwarfed by the impact of nuclear war, which will cause the vast majority of the damage, causes the first catastrophe that causes civilizational collapse, and causes the deaths of billions. Nonetheless, I struggle to see how this by itself makes the impact of SRM induced forcing negligible. For instance, if, as Doug MacMartin is suggesting, SRM termination reduces the delta T from nuclear winter, even by 1K, surely that's somewhat significant. Please correct me if such an assessment is wrong. Similarly, if SRM makes the whole scenario worse, in the way that Seth Baum suggests in Baum (2013), then that is also significant. Even if it is small compared to the impact of nuclear winter, none of these plausible impacts seem negligible to me, even if we were only doing 1K of cooling with SRM (even less so if doing 3K of cooling). If I care about increasing the chance the civilizational collapse isn't permanent/ doesn't result in human extinction by any amoun

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

Hi all,
I think I ought to clarify what I am trying to do and repose the question, 
as well as respond to all the replies.
What I am attempting to do is this: Under low probability scenarios of 
nuclear war with high SRM burden (maybe due to a large warming, either 
because of high emissions or high ECS and TCR, either being far in excess 
of either the most likely scenarios or of the median values), would the 
termination "shock" have any effect? Not just would it be dwarfed by the 
effect of nuclear war, but would it truly be negligible in comparison? If 
not, what would the effect be?
Why do I care about this; after all, a global nuclear war capable of 
producing civilizational collapse enough to cause SRM termination would 
kill billions, and as Mike MacKraken suggests, would massively change 
society (what I am terming "collapse")? 
- From many philosophical worldviews, it is important to know if such 
collapse would be permanent or lead to human extinction, or whether it is 
recoverable. These obviously exist on a spectrum, and thus whether 
something like SRM contributes to it being easier/harder for recovery from 
collapse is really important.
- Whilst it is true that, in terms of the arguments you have been making, 
nuclear war is the real and most important problem, it is still important 
to know if large scale termination shock contributes in any meaningful way 
to either slightly increasing or slightly decreasing the damages from the 
nuclear winter. Such relatively small changes (a single order of magnitude 
lower lets say) may be important in terms of whether a collapse is 
recoverable (note the word may, I would be happy to hear evidence to the 
contrary)

Now onto responses to the points raised:
In response to Alan and Gilles:
In Alan's paper that Gilles cites, the temperature anomaly is less than 8K, 
and in Coupe et al 2019 which Alan cites on his website (as one of many 
excellent papers that he has co-authored), the temperature anomaly is of 
-10K. Of course, the impacts are not limited to cooling (nor the impacts of 
nuclear war limited to nuclear winter). Nonetheless, and please do tell me 
if I am missing something key here, it doesn't seem that the temperature 
anomaly that SRM termination would cause (be it +1K or +3K or others) would 
be entirely negligible. Of course, it would be dwarfed by the impact of 
nuclear war, which will cause the vast majority of the damage, causes the 
first catastrophe that causes civilizational collapse, and causes the 
deaths of billions. Nonetheless, I struggle to see how this by itself makes 
the impact of SRM induced forcing negligible. For instance, if, as Doug 
MacMartin is suggesting, SRM termination reduces the delta T from nuclear 
winter, even by 1K, surely that's somewhat significant. Please correct me 
if such an assessment is wrong. Similarly, if SRM makes the whole scenario 
worse, in the way that Seth Baum suggests in Baum (2013), then that is also 
significant. Even if it is small compared to the impact of nuclear winter, 
none of these plausible impacts seem negligible to me, even if we were only 
doing 1K of cooling with SRM (even less so if doing 3K of cooling). If I 
care about increasing the chance the civilizational collapse isn't 
permanent/ doesn't result in human extinction by any amount (be it 1 or 
10%), then these questions seem significant. 

In response to Renaud and Andrew
The catastrophe proposed in this scenario is a global catastrophe that 
essentially collapses civilisation, reducing the capacity of human 
organisation to such a degree that sustaining SRM would simply not be 
possible. This is the reason I somewhat doubt that a more local nuclear war 
could stop our capacity to carry out SRM, as I find the arguments in Parker 
and Irvine (2018) with regards to the requirements for termination shock to 
be robust and compelling, hence the scenario I have set out. 

In response to a lot of the general vibe of the conversation:
Of course nuclear war is the main thing to worry about; it is the dominant 
major catastrophe. However, what I am trying to do is a risk-risk analysis 
of what Tang and Kemp (2021) 
[https://www.frontiersin.org/articles/10.3389/fclim.2021.720312/full#:~:text=Stratospheric%20Aerosol%20Injection%20and%20Global%20Catastrophic%20Risk,-Aaron%20Tang1&text=Injecting%20particles%20into%20atmosphere%20to,the%20threat%20of%20climate%20change.]
 
describe as latent risk of SRM; key global catastrophic risks that are only 
activiated given certain scenarios. In particular, I am trying to test the 
robustness of the concept of "double catastrophe" of SRM being 
significantly worse than the "single catastrophe" given the same warming 
but no SRM, which is introduced in Baum et al 2013 
[https://gcrinstitute.org/papers/003_double-catastrophe.pdf] without much 
supporting evidence. I am sceptical that a nuclear war + SRM is worse than 
a nuclear war with no SRM; in fact, if anything, the former seems on first 
a

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gilles de Brouwer]

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 
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, 
> 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  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 

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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, 
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  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 UniversityE-mail:
>> rob...@envsci.rutgers.edu
>> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
>> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>>
>> [image: Signature]
>>
>>
>> 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 t

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Michael MacCracken]

There is a real question about how much smoke an India-Pakistan conflict 
could generate and loft. So, in a normal scenario, one shoots one's 
weapons at the other sides offensive weapons (missiles, control systems, 
maybe fuel storage locations, etc.) and not clear (at least to me) that 
this could create a hot enough fire to really loft much smoke--lighting 
the Kuwait oil fields did not really loft much, in part due to the 
typical inversion that prevails. Were the cities attacked, it is also 
just not clear there is enough burnable material to loft smoke, given 
wood is not a typical building material, at least in areas I have 
visited. And a war during the monsoon season would also not seem likely 
to loft much smoke. Might one hae enough to affect the weather--perhaps, 
but the thermal capacity of the oceans is very large and I'd suggest it 
would take a lot more smoke than that to cause a significant effect.


Mike MacC

On 7/26/22 5:48 PM, Andrew Lockley wrote:
I'm not sure I agree with the framing that is being used here. We do 
not have to imagine a global cataclysm. Alternatively we could imagine 
that India is the only country engaging in geoengineering, and it 
engages in a locally catastrophic but limited war with Pakistan. In 
this case, we could consider a situation where the global economy was 
suffering little Direct damage, but there was a nuclear winter as a 
result of large urban fires. If both geoengineering hardware and know 
how is lost in the war, termination shock occurs simultaneously with 
nuclear winter. That might serve to hasten and worsen the sudden 
change in temperature coming out of a nuclear winter leading to a 
nuclear summer


A

On Tue, 26 Jul 2022, 22:33 Daniele Visioni, 
 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 
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 
Rutgers UniversityE-mail:
rob...@envsci.rutgers.edu
14 College Farm Road

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Andrew Lockley]

I'm not sure I agree with the framing that is being used here. We do not
have to imagine a global cataclysm. Alternatively we could imagine that
India is the only country engaging in geoengineering, and it engages in a
locally catastrophic but limited war with Pakistan. In this case, we could
consider a situation where the global economy was suffering little Direct
damage, but there was a nuclear winter as a result of large urban fires. If
both geoengineering hardware and know how is lost in the war, termination
shock occurs simultaneously with nuclear winter. That might serve to hasten
and worsen the sudden change in temperature coming out of a nuclear winter
leading to a nuclear summer

A

On Tue, 26 Jul 2022, 22:33 Daniele Visioni, 
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  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 UniversityE-mail:
>> rob...@envsci.rutgers.edu
>> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
>> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>>
>> [image: Signature]
>>
>>
>> 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 rel

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Daniele Visioni]

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  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
>> Rutgers UniversityE-mail: 
>> rob...@envsci.rutgers.edu
>> 14 College Farm Roadhttp://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

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Michael MacCracken]

I'm with Alan on this one.

With 3 C warming offset by SAI, if done thoughtfully the society and 
agriculture  would have been adjusting along the way, and then comes 
nuclear war to disturb that ongoing situation.


And as the SCOPE study on the consequences of nuclear war made clear, 
there is the matter of the direct damage. As that report noted it would 
take destruction of only a few of the world's financial centers to 
collapse international trade of medicines, seeds, fertilizers, grain and 
much more (computer chips, coffee). As we are seeing from the invasion 
of Ukraine, which is one of the top exporters of grains and fertilizer, 
disrupting this producing area has prospects for causing widespread 
starvation. For each of the major grains in international trade, 
something like 90% comes from typically five countries or so, with their 
exports going to of order 100 countries importing the grain in order to 
provide reasonably priced food for their people. And then add sudden 
disruption of the weather in these key zones and making it difficult for 
nations around the world, global nuclear war would be overwhelmingly worse.


What would happen to the conditions of the following years might be of 
theoretical interest, but the consequences of the first months and year 
would have created such disruption that the society you'd be considering 
would be almost unimaginably different.


Mike MacCracken

On 7/26/22 11:20 AM, Gideon Futerman 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 
Rutgers UniversityE-mail:
rob...@envsci.rutgers.edu
14 College Farm Road http://people.envsci.rutgers.edu/robock
New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock

Signature


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

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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 UniversityE-mail: 
> rob...@envsci.rutgers.edu
> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>
> [image: Signature] 
>
>
> 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 UniversityE-mail: 
>> rob...@envsci.rutgers.edu
>> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
>> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>>
>> [image: Signature] 
>>
>>
>> On 7/26/2022 10:03 AM, Gideon Futerman wrote:
>>
>> As part of th

Re: [geo] Nuclear Winter and SRM (including termination shock)

[Alan Robock ☮]

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
Rutgers UniversityE-mail: 
rob...@envsci.rutgers.edu

14 College Farm Road http://people.envsci.rutgers.edu/robock
New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock

Signature


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 
Rutgers UniversityE-mail:
rob...@envsci.rutgers.edu
14 College Farm Road http://people.envsci.rutgers.edu/robock
New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock

Signature


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?


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Re: [geo] Nuclear Winter and SRM (including termination shock)

[Gideon Futerman]

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 UniversityE-mail: 
> rob...@envsci.rutgers.edu
> 14 College Farm Roadhttp://people.envsci.rutgers.edu/robock
> New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock
>
> [image: Signature] 
>
>
> 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 
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>  
> 
> .
>
>
>

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Re: [geo] Nuclear Winter and SRM (including termination shock)

[Alan Robock ☮]

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
Rutgers UniversityE-mail: 
rob...@envsci.rutgers.edu

14 College Farm Road http://people.envsci.rutgers.edu/robock
New Brunswick, NJ 08901-8551 ☮ https://twitter.com/AlanRobock

Signature


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?



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