On 26 Jul 2022, at 17:20, Gideon Futerman <[email protected]>
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 <http://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 <tel:(848)%20932-5751>
Rutgers University E-mail:
[email protected]
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 <tel:(848)%20932-5751>
Rutgers University E-mail:
[email protected]
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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