Re: [geo] Background-Greenland collapse

[Jasmin S. A. Link]

Thank you Doug,

> If you would plan the potential deployment of SRM (especially on a 
large-scale) you would in the same way have to consider the potential 
side effects beforehand to assure to decouple a deployment of SRM from 
these potential side effects. Otherwise you would risk the accumulation 
in acidification of the oceans, self-reinforcing the reduction in 
biodiversity, loss in coral reefs, accumulating in social tensions (just 
to name a few of the interconnected potential side effects, cp. Figure 
3.1.,p.71 in the transdisciplinary network of potential side effects in: 
https://www.iass-potsdam.de/sites/default/files/2018-06/EuTRACE_report_digital_second_edition.pdf 
). <


Regarding ocean acidification and acid rain: Yes, putting up mirrors 
would not directly cause ocean acidification but SAI might cause acid 
rain (depending on the aerosol used). And no, it still is related via an 
indirect effect in terms of social behavior: If people comprehend SRM in 
a way as that there is some sort of technical compensation happening for 
their carbon emissions, they are likely to rather not reduce their own 
carbon emissions, but instead increase their own carbon emissions. This 
is marked in Figure 3.1. as "less necessity for direct emission 
reduction?" connected to a "rise of CO2 emissions", which causes 
multiple feedbacks such as the necessity to further increase the SAI 
deployment. I think, there have been more recent simulation studies at 
MIT on this kind of behavior that support the relevance of this 
potential indirect effect.


In my argument on the potential accumulation in acidification of the 
oceans, I had this indirect effect of the SRM deployment on the rather 
increased carbon emission behavior in mind: Officially applying a method 
to reduce global warming which might be understood as "fixing the 
problem with engineering" might rather reduce than increase individual 
mitigation efforts. (Of course, we know that the problem is not really 
fixed, but try to explain that to usual consumers who would know at some 
point that their government would regularly spend large sums of money on 
SRM and who might feel more comfortable to stick and increase their 
former behavior than to really change it, due to path dependence).


Best,

Jasmin


Am 15.08.2020 um 23:40 schrieb Douglas MacMartin:


Thanks Jasmin,

Agree that all the side effects of SRM need to be considered, and need 
to evaluate options holistically.


That said, SRM does not cause ocean acidification; CO2 causes ocean 
acidification.  So one should never list ocean acidification as a side 
effect.  (It is true that SRM doesn’t solve ocean acidification, but 
it also doesn’t solve car accidents… and no-one lists that as a reason 
not to consider SRM.)  Implicit in listing acidification in any 
discussion of SRM is an assumption that somehow we’re required to 
choose between reducing CO2 or using SRM, in much the same way that we 
have to choose whether to drive safely or wear a seat belt, but we’re 
not allowed to do both.


doug

*From:*geoengineering@googlegroups.com 
 *On Behalf Of *Jasmin S. A. Link

*Sent:* Saturday, August 15, 2020 8:32 AM
*To:* geoengineering@googlegroups.com
*Subject:* Re: [geo] Background-Greenland collapse

"The more advanced the process, the more momentum it has, and the 
harder it is to stop or reverse." The same can count for social 
dynamics. Self-reinforcing processes with the tendency towards a 
lock-in are path-dependent processes. That is, why it is not easy to 
just change carbon intensive behavior towards low carbon emission 
behavior. Many social, economical, and technical processes have the 
production of carbon emissions as side effects which accumulate during 
the intensifying self-reinforcing processes (cp. Figure 4 p. 63 in 
https://ediss.sub.uni-hamburg.de/volltexte/2020/10431/pdf/Dissertation.pdf 
).


But what about the side effects of SRM that would accumulate over time 
while deployment in an intensity of "driving the earth into a glacial 
period"?


It is necessary to decouple self-reinforcing processes from producing 
carbon emissions as a side effect. And try to potentially include the 
reduction of carbon emissions as side effects of new self-reinforcing 
processes that show the dynamic of "the more advanced the process, the 
more momentum it has, and the harder it is to stop or reverse".


If you would plan the potential deployment of SRM (especially on a 
large-scale) you would in the same way have to consider the potential 
side effects beforehand to assure to decouple a deployment of SRM from 
these potential side effects. Otherwise you would risk the 
accumulation in acidification of the oceans, self-reinforcing the 
reduction in biodiversity, loss in coral reefs, accumulating in social 
tensions (just to name a few of the interconnected potential side 
effects, cp. Figure 3.1.,p.71 in the transdisciplinary network of 
potential side effects in: 

Re: [geo] Background-Greenland collapse

[Kevin Lister]

Doug,

If it where only the Greenland ice sheet that was suffering catastrophic
and irreversible change,  we might be able to relax and wait 10 to 15
years,  but every part of the world and all it's ecosystems are facing
similar destructive change,  from the coral  reefs  to the subsea
permafrost.  This is happening as the global population is heading towards
10 billion with almost everyone already at each throats.

If we delay SRM then the scale of the necessary intervention will grow with
the delay,  most likely exponentially,  and the risks of unintended
consequences or out right failure will grow accordingly. At the same time,
society could be at a point of break down making any coordinated plan
virtually impossible  and debates about agreeing on global governance
irrelevant.

Maybe some elements of the paper that was posted can be quibbled over,  but
the need to make an urgent start on SRM can't be.

Kevin

On Sat, 15 Aug 2020, 22:35 Douglas MacMartin,  wrote:

> Hi Mike,
>
>
>
> -  I don’t know (and I’m not sure anyone really does) how much
> Greenland ice sheet mass loss can accelerate, but agree that it won’t stay
> at the current rate.
>
> -  Mainly my point was that the media link Andrew sent was silly
> by implying that the 6m could happen in decades (even if it didn’t
> technically say that), and the paper doesn’t make any claims about how much
> the loss rate will accelerate… and to support the claim that geoengineering
> is the **ONLY** way to avoid catastrophic sea level rise requires
> evidence that we need to intervene now rather than over the rest of the
> century.  I do agree that there’s good reason to suspect that Andrew’s
> claim may be true, but it is certainly not supported by the paper he was
> referring to, and I don’t think we can prove that the claim is true.
>
> -  Paleo evidence makes it clear that staying at even the current
> CO2 levels for millennia would be catastrophic.  It doesn’t do a great job
> of constraining how rapidly we need to change, e.g. if CDR over the rest of
> the century would also be an adequate alternative to SRM.  (And paleo
> evidence also shows that it is possible to get ~5m of SLR in a single
> century, but that’s coming out of the last glacial when there was a lot
> more available to be melted, and that doesn’t say that it is possible to
> get anything close to that this century.)
>
> -  Arguably this is simply quibbling over whether we can prove
> we’re past the point where even aggressive CDR would work, or whether
> there’s simply a risk that we’re past that point, in which case arguing
> over whether that is 20% or 50% or 10% might not matter for policy.  I do
> agree that we are gambling with the climate, and with odds that no-one
> would accept in any other circumstance.
>
> -  Personally, given how little research has been done, I don’t
> think there’s strong justification for saying that the long-term climate
> consequences of waiting another 10-15 years for research (and to develop
> governance capacity) will be so bad that we should go ahead and deploy
> something now without doing the research (though if we did deploy something
> now, I’d worry more about the societal response than the physical issues).
> But, just like the US didn’t use the first few months of this year to
> prepare for covid when it knew it was coming, it would be truly awful to
> not do the research now, leaving us in the same boat yet another decade
> later.
>
> doug
>
>
>
> *From:* Michael MacCracken 
> *Sent:* Saturday, August 15, 2020 12:54 PM
> *To:* Douglas MacMartin ; andrew.lock...@gmail.com;
> geoengineering 
> *Subject:* Re: [geo] Background-Greenland collapse
>
>
>
> Hi Doug et al.--I'm a bit late to this particular conversation, but I am
> astonished by the suggestion that Greenland can only cause such a small
> potential rate of rise in sea level. There was just a kerfuffle with the
> IPCC authors on their draft projections of rates (see attached letter).
> While surface melt rate may be relatively slow as often calculated, it is
> not the main loss of mass process--ice stream flow is very likely the major
> loss rate once it gets going and the calculations that are done in most
> models do not include this term, nor do they include the effects of ice
> shelf thinning that is going on. From the peak of the last interglacial to
> 8 ka, sea level rose at an average rate of a meter per century while global
> average temperature rose at an average rate of a degree C per 2000 years,
> and the CO2 concentration was less than 300 ppm. The documentary "Chasing
> Ice" shows how fast ice can disappear, and not just in the ice stream
> calving that is the most amazing aspect of that film. And paleo evidence
> also makes very clear that ice sheets go away much faster than they build
> up.
>
> And the question is not so much when the cities will be under water as
> when it will become inevitable that they will be under 

Re: [geo] Background-Greenland collapse

[Russell Seitz]

Mike, Douglas thinks:
 "it is possible that neither of those options would arrest mass loss 
without cooling beyond preindustrial, and that over the ensuing millennium 
we would eventually lose our coastal cities no matter what we do, "

But it is curious how may former seaports have ended up stranded inland by 
sediment transport-  Troy and Pisa fpr instance.We need to consider  how 
many of "our" major coastal cities existed in recognizable form a hundred, 
let alone a thousand years ago? Modern demographics have driven the rise of 
skyscrapers out of former  swamps from Miami to Singapore, and experience 
architectural rollover on a time scale reckoned in generations, not 
centuries. 

Coastal plains may be doomed, but  San Francisco  and Hong Kong are a ar 
cry from Houston and Lagos. Has the IPCC  mapped and counted  the fraction 
of current  coastal city  populations that can gain a meter of elevation by 
walking a kilometer inland from the neighborhoods in which they presently 
reside?  There's more at issue than urban islands like Venice. Cities have 
a life of their own , and wherever waterfronts  can migrate inland, 
waterfront properties will continue to be built behind them


On Saturday, August 15, 2020 at 12:54:14 PM UTC-4 Mike MacCracken wrote:

> Hi Doug et al.--I'm a bit late to this particular conversation, but I am 
> astonished by the suggestion that Greenland can only cause such a small 
> potential rate of rise in sea level. There was just a kerfuffle with the 
> IPCC authors on their draft projections of rates (see attached letter). 
> While surface melt rate may be relatively slow as often calculated, it is 
> not the main loss of mass process--ice stream flow is very likely the major 
> loss rate once it gets going and the calculations that are done in most 
> models do not include this term, nor do they include the effects of ice 
> shelf thinning that is going on. From the peak of the last interglacial to 
> 8 ka, sea level rose at an average rate of a meter per century while global 
> average temperature rose at an average rate of a degree C per 2000 years, 
> and the CO2 concentration was less than 300 ppm. The documentary "Chasing 
> Ice" shows how fast ice can disappear, and not just in the ice stream 
> calving that is the most amazing aspect of that film. And paleo evidence 
> also makes very clear that ice sheets go away much faster than they build 
> up.
>
> And the question is not so much when the cities will be under water as 
> when it will become inevitable that they will be under water--given that 
> consideration and the paleo sensitivity being something like 15-20 meters 
> per degree C warming (and this is not just me saying this, but see Eric 
> Rignot talk to the NAS last year--see https://vimeo.com/332486918 ).
>
> Based on this sensitivity, we're already past the point where it would be 
> good to have climate intervention underway if we want to avoid significant 
> and early risk to our cities with a very high likelihood (and this is the 
> criterion that is often used in building infrastructure--avoiding 1 in 100 
> year events or even rarer ones--consider the Dutch for their levees--1 in 
> 10,000 year storms).
>
> Mike MacCracken
>
>
>  
>
>
>
> On 8/15/20 7:03 AM, Douglas MacMartin wrote:
>
> What is not correct in the media report is this sentence: “This process, 
> however, would take decades.”  Well, I guess arguably that’s true, it’s 
> just it would take a LOT of decades.  Melt rate is currently of order 
> 1-2mm/yr equivalent SLR, so to get the 6m from melting all of Greenland 
> would take a few thousand years.  Obviously it can speed up a lot, but 
> “hey, it’s losing mass” does not remotely imply “therefore we only have a 
> few decades before we lose our coastal cities”.  So no, you can’t use this 
> study to claim that geoengineering is required to keep our coastal cities.  
> The problem with relying on mitigation+CDR is time-scale, but this study 
> doesn’t prove that our response time-scale needs to be faster than what CDR 
> can (at least hypothetically) provide.  
>
> d
>
> *From:* geoengi...@googlegroups.com  *On 
> Behalf Of *Andrew Lockley
> *Sent:* Saturday, August 15, 2020 3:40 AM
> *To:* geoengineering 
> *Subject:* [geo] Background-Greenland collapse
>
>  
>
> If this study is correct https://www.nature.com/articles/s43247-020-0001-2
>
> And is correctly reported here 
> https://mobile.reuters.com/article/amp/idUSKCN25A2X3
>
> Then it appears to back up a point that I have been making for a long 
> time: geoengineering is required, if we are to keep our coastal cities. I 
> do not see economic or political feasibility for large scale CDR to tackle 
> historic emissions, and thus the task must fall to SRM. 
>
>  
>
> Nobody has managed to rause an objection to this argument to date. I'd be 
> grateful if those who might disagree were to raise counter arguments now. 
>
>  
>
> If the situation is as I understand it, prevarication has 

RE: [geo] Background-Greenland collapse

[Douglas MacMartin]

Thanks Jasmin,

Agree that all the side effects of SRM need to be considered, and need to 
evaluate options holistically.

That said, SRM does not cause ocean acidification; CO2 causes ocean 
acidification.  So one should never list ocean acidification as a side effect.  
(It is true that SRM doesn’t solve ocean acidification, but it also doesn’t 
solve car accidents… and no-one lists that as a reason not to consider SRM.)  
Implicit in listing acidification in any discussion of SRM is an assumption 
that somehow we’re required to choose between reducing CO2 or using SRM, in 
much the same way that we have to choose whether to drive safely or wear a seat 
belt, but we’re not allowed to do both.

doug

From: geoengineering@googlegroups.com  On 
Behalf Of Jasmin S. A. Link
Sent: Saturday, August 15, 2020 8:32 AM
To: geoengineering@googlegroups.com
Subject: Re: [geo] Background-Greenland collapse


"The more advanced the process, the more momentum it has, and the harder it is 
to stop or reverse." The same can count for social dynamics. Self-reinforcing 
processes with the tendency towards a lock-in are path-dependent processes. 
That is, why it is not easy to just change carbon intensive behavior towards 
low carbon emission behavior. Many social, economical, and technical processes 
have the production of carbon emissions as side effects which accumulate during 
the intensifying self-reinforcing processes (cp. Figure 4 p. 63 in 
https://ediss.sub.uni-hamburg.de/volltexte/2020/10431/pdf/Dissertation.pdf ).

But what about the side effects of SRM that would accumulate over time while 
deployment in an intensity of "driving the earth into a glacial period"?

It is necessary to decouple self-reinforcing processes from producing carbon 
emissions as a side effect. And try to potentially include the reduction of 
carbon emissions as side effects of new self-reinforcing processes that show 
the dynamic of "the more advanced the process, the more momentum it has, and 
the harder it is to stop or reverse".

If you would plan the potential deployment of SRM (especially on a large-scale) 
you would in the same way have to consider the potential side effects 
beforehand to assure to decouple a deployment of SRM from these potential side 
effects. Otherwise you would risk the accumulation in acidification of the 
oceans, self-reinforcing the reduction in biodiversity, loss in coral reefs, 
accumulating in social tensions (just to name a few of the interconnected 
potential side effects, cp. Figure 3.1.,p.71 in the transdisciplinary network 
of potential side effects in: 
https://www.iass-potsdam.de/sites/default/files/2018-06/EuTRACE_report_digital_second_edition.pdf
 ).

Furthermore, with SRM you address the global mean temperature. If this would 
work at all, this would not imply the globally even reduction of temperature, 
regional effects may differ a lot, potentially increasing also the climate 
related risks for coastal cities, which you have mentioned as your main concern 
to safe.

Best,

Jasmin


Am 15.08.2020 um 13:19 schrieb Andrew Lockley:
The more advanced the process, the more momentum it has, and the harder it is 
to stop or reverse. It's unclear whether we could arrest mass loss, without 
driving the earth into a glacial period (colloquially, an ice age). I don't 
think there has been any serious modelling work done on ice loss reversal, or 
even if the models are capable of doing this with any useful accuracy.

On Sat, 15 Aug 2020, 12:03 Douglas MacMartin, 
mailto:dgm...@cornell.edu>> wrote:

What is not correct in the media report is this sentence: “This process, 
however, would take decades.”  Well, I guess arguably that’s true, it’s just it 
would take a LOT of decades.  Melt rate is currently of order 1-2mm/yr 
equivalent SLR, so to get the 6m from melting all of Greenland would take a few 
thousand years.  Obviously it can speed up a lot, but “hey, it’s losing mass” 
does not remotely imply “therefore we only have a few decades before we lose 
our coastal cities”.  So no, you can’t use this study to claim that 
geoengineering is required to keep our coastal cities.  The problem with 
relying on mitigation+CDR is time-scale, but this study doesn’t prove that our 
response time-scale needs to be faster than what CDR can (at least 
hypothetically) provide.
d
From: geoengineering@googlegroups.com 
mailto:geoengineering@googlegroups.com>> On 
Behalf Of Andrew Lockley
Sent: Saturday, August 15, 2020 3:40 AM
To: geoengineering 
mailto:geoengineering@googlegroups.com>>
Subject: [geo] Background-Greenland collapse

If this study is correct https://www.nature.com/articles/s43247-020-0001-2
And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3
Then it appears to back up a point that I have been making for a long time: 
geoengineering is required, if we are to keep our coastal cities. I do not see 
economic or political feasibility for 

RE: [geo] Background-Greenland collapse

[Douglas MacMartin]

Hi Mike,


-  I don’t know (and I’m not sure anyone really does) how much 
Greenland ice sheet mass loss can accelerate, but agree that it won’t stay at 
the current rate.

-  Mainly my point was that the media link Andrew sent was silly by 
implying that the 6m could happen in decades (even if it didn’t technically say 
that), and the paper doesn’t make any claims about how much the loss rate will 
accelerate… and to support the claim that geoengineering is the *ONLY* way to 
avoid catastrophic sea level rise requires evidence that we need to intervene 
now rather than over the rest of the century.  I do agree that there’s good 
reason to suspect that Andrew’s claim may be true, but it is certainly not 
supported by the paper he was referring to, and I don’t think we can prove that 
the claim is true.

-  Paleo evidence makes it clear that staying at even the current CO2 
levels for millennia would be catastrophic.  It doesn’t do a great job of 
constraining how rapidly we need to change, e.g. if CDR over the rest of the 
century would also be an adequate alternative to SRM.  (And paleo evidence also 
shows that it is possible to get ~5m of SLR in a single century, but that’s 
coming out of the last glacial when there was a lot more available to be 
melted, and that doesn’t say that it is possible to get anything close to that 
this century.)

-  Arguably this is simply quibbling over whether we can prove we’re 
past the point where even aggressive CDR would work, or whether there’s simply 
a risk that we’re past that point, in which case arguing over whether that is 
20% or 50% or 10% might not matter for policy.  I do agree that we are gambling 
with the climate, and with odds that no-one would accept in any other 
circumstance.

-  Personally, given how little research has been done, I don’t think 
there’s strong justification for saying that the long-term climate consequences 
of waiting another 10-15 years for research (and to develop governance 
capacity) will be so bad that we should go ahead and deploy something now 
without doing the research (though if we did deploy something now, I’d worry 
more about the societal response than the physical issues).  But, just like the 
US didn’t use the first few months of this year to prepare for covid when it 
knew it was coming, it would be truly awful to not do the research now, leaving 
us in the same boat yet another decade later.
doug

From: Michael MacCracken 
Sent: Saturday, August 15, 2020 12:54 PM
To: Douglas MacMartin ; andrew.lock...@gmail.com; 
geoengineering 
Subject: Re: [geo] Background-Greenland collapse


Hi Doug et al.--I'm a bit late to this particular conversation, but I am 
astonished by the suggestion that Greenland can only cause such a small 
potential rate of rise in sea level. There was just a kerfuffle with the IPCC 
authors on their draft projections of rates (see attached letter). While 
surface melt rate may be relatively slow as often calculated, it is not the 
main loss of mass process--ice stream flow is very likely the major loss rate 
once it gets going and the calculations that are done in most models do not 
include this term, nor do they include the effects of ice shelf thinning that 
is going on. From the peak of the last interglacial to 8 ka, sea level rose at 
an average rate of a meter per century while global average temperature rose at 
an average rate of a degree C per 2000 years, and the CO2 concentration was 
less than 300 ppm. The documentary "Chasing Ice" shows how fast ice can 
disappear, and not just in the ice stream calving that is the most amazing 
aspect of that film. And paleo evidence also makes very clear that ice sheets 
go away much faster than they build up.

And the question is not so much when the cities will be under water as when it 
will become inevitable that they will be under water--given that consideration 
and the paleo sensitivity being something like 15-20 meters per degree C 
warming (and this is not just me saying this, but see Eric Rignot talk to the 
NAS last year--see https://vimeo.com/332486918 ).

Based on this sensitivity, we're already past the point where it would be good 
to have climate intervention underway if we want to avoid significant and early 
risk to our cities with a very high likelihood (and this is the criterion that 
is often used in building infrastructure--avoiding 1 in 100 year events or even 
rarer ones--consider the Dutch for their levees--1 in 10,000 year storms).

Mike MacCracken







On 8/15/20 7:03 AM, Douglas MacMartin wrote:

What is not correct in the media report is this sentence: “This process, 
however, would take decades.”  Well, I guess arguably that’s true, it’s just it 
would take a LOT of decades.  Melt rate is currently of order 1-2mm/yr 
equivalent SLR, so to get the 6m from melting all of Greenland would take a few 
thousand years.  Obviously it can speed up a lot, but “hey, it’s losing mass” 
does 

Re: [geo] Background-Greenland collapse

[Michael MacCracken]

Hi Doug et al.--I'm a bit late to this particular conversation, but I am 
astonished by the suggestion that Greenland can only cause such a small 
potential rate of rise in sea level. There was just a kerfuffle with the 
IPCC authors on their draft projections of rates (see attached letter). 
While surface melt rate may be relatively slow as often calculated, it 
is not the main loss of mass process--ice stream flow is very likely the 
major loss rate once it gets going and the calculations that are done in 
most models do not include this term, nor do they include the effects of 
ice shelf thinning that is going on. From the peak of the last 
interglacial to 8 ka, sea level rose at an average rate of a meter per 
century while global average temperature rose at an average rate of a 
degree C per 2000 years, and the CO2 concentration was less than 300 
ppm. The documentary "Chasing Ice" shows how fast ice can disappear, and 
not just in the ice stream calving that is the most amazing aspect of 
that film. And paleo evidence also makes very clear that ice sheets go 
away much faster than they build up.


And the question is not so much when the cities will be under water as 
when it will become inevitable that they will be under water--given that 
consideration and the paleo sensitivity being something like 15-20 
meters per degree C warming (and this is not just me saying this, but 
see Eric Rignot talk to the NAS last year--see 
https://vimeo.com/332486918 ).


Based on this sensitivity, we're already past the point where it would 
be good to have climate intervention underway if we want to avoid 
significant and early risk to our cities with a very high likelihood 
(and this is the criterion that is often used in building 
infrastructure--avoiding 1 in 100 year events or even rarer 
ones--consider the Dutch for their levees--1 in 10,000 year storms).


Mike MacCracken






On 8/15/20 7:03 AM, Douglas MacMartin wrote:


What is not correct in the media report is this sentence: “This 
process, however, would take decades.” Well, I guess arguably that’s 
true, it’s just it would take a LOT of decades.  Melt rate is 
currently of order 1-2mm/yr equivalent SLR, so to get the 6m from 
melting all of Greenland would take a few thousand years.  Obviously 
it can speed up a lot, but “hey, it’s losing mass” does not remotely 
imply “therefore we only have a few decades before we lose our coastal 
cities”.  So no, you can’t use this study to claim that geoengineering 
is required to keep our coastal cities.  The problem with relying on 
mitigation+CDR is time-scale, but this study doesn’t prove that our 
response time-scale needs to be faster than what CDR can (at least 
hypothetically) provide.


d

*From:*geoengineering@googlegroups.com 
 *On Behalf Of *Andrew Lockley

*Sent:* Saturday, August 15, 2020 3:40 AM
*To:* geoengineering 
*Subject:* [geo] Background-Greenland collapse

If this study is correct https://www.nature.com/articles/s43247-020-0001-2

And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3

Then it appears to back up a point that I have been making for a long 
time: geoengineering is required, if we are to keep our coastal 
cities. I do not see economic or political feasibility for large scale 
CDR to tackle historic emissions, and thus the task must fall to SRM.


Nobody has managed to rause an objection to this argument to date. I'd 
be grateful if those who might disagree were to raise counter 
arguments now.


If the situation is as I understand it, prevarication has no clear 
benefits, and we should thus move quickly to readiness for deployment.


Andrew

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Re: [geo] Background-Greenland collapse

[Jasmin S. A. Link]

"The more advanced the process, the more momentum it has, and the harder 
it is to stop or reverse." The same can count for social dynamics. 
Self-reinforcing processes with the tendency towards a lock-in are 
path-dependent processes. That is, why it is not easy to just change 
carbon intensive behavior towards low carbon emission behavior. Many 
social, economical, and technical processes have the production of 
carbon emissions as side effects which accumulate during the 
intensifying self-reinforcing processes (cp. Figure 4 p. 63 in 
https://ediss.sub.uni-hamburg.de/volltexte/2020/10431/pdf/Dissertation.pdf 
).


But what about the side effects of SRM that would accumulate over time 
while deployment in an intensity of "driving the earth into a glacial 
period"?


It is necessary to decouple self-reinforcing processes from producing 
carbon emissions as a side effect. And try to potentially include the 
reduction of carbon emissions as side effects of new self-reinforcing 
processes that show the dynamic of "the more advanced the process, the 
more momentum it has, and the harder it is to stop or reverse".


If you would plan the potential deployment of SRM (especially on a 
large-scale) you would in the same way have to consider the potential 
side effects beforehand to assure to decouple a deployment of SRM from 
these potential side effects. Otherwise you would risk the accumulation 
in acidification of the oceans, self-reinforcing the reduction in 
biodiversity, loss in coral reefs, accumulating in social tensions (just 
to name a few of the interconnected potential side effects, cp. Figure 
3.1.,p.71 in the transdisciplinary network of potential side effects in: 
https://www.iass-potsdam.de/sites/default/files/2018-06/EuTRACE_report_digital_second_edition.pdf 
).


Furthermore, with SRM you address the global mean temperature. If this 
would work at all, this would not imply the globally even reduction of 
temperature, regional effects may differ a lot, potentially increasing 
also the climate related risks for coastal cities, which you have 
mentioned as your main concern to safe.


Best,

Jasmin


Am 15.08.2020 um 13:19 schrieb Andrew Lockley:
The more advanced the process, the more momentum it has, and the 
harder it is to stop or reverse. It's unclear whether we could arrest 
mass loss, without driving the earth into a glacial period 
(colloquially, an ice age). I don't think there has been any serious 
modelling work done on ice loss reversal, or even if the models are 
capable of doing this with any useful accuracy.


On Sat, 15 Aug 2020, 12:03 Douglas MacMartin, > wrote:


What is not correct in the media report is this sentence: “This
process, however, would take decades.” Well, I guess arguably
that’s true, it’s just it would take a LOT of decades.  Melt rate
is currently of order 1-2mm/yr equivalent SLR, so to get the 6m
from melting all of Greenland would take a few thousand years. 
Obviously it can speed up a lot, but “hey, it’s losing mass” does
not remotely imply “therefore we only have a few decades before we
lose our coastal cities”.  So no, you can’t use this study to
claim that geoengineering is required to keep our coastal cities. 
The problem with relying on mitigation+CDR is time-scale, but this
study doesn’t prove that our response time-scale needs to be
faster than what CDR can (at least hypothetically) provide.

d

*From:*geoengineering@googlegroups.com

mailto:geoengineering@googlegroups.com>> *On Behalf Of *Andrew
Lockley
*Sent:* Saturday, August 15, 2020 3:40 AM
*To:* geoengineering mailto:geoengineering@googlegroups.com>>
*Subject:* [geo] Background-Greenland collapse

If this study is correct
https://www.nature.com/articles/s43247-020-0001-2

And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3

Then it appears to back up a point that I have been making for a
long time: geoengineering is required, if we are to keep our
coastal cities. I do not see economic or political feasibility for
large scale CDR to tackle historic emissions, and thus the task
must fall to SRM.

Nobody has managed to rause an objection to this argument to date.
I'd be grateful if those who might disagree were to raise counter
arguments now.

If the situation is as I understand it, prevarication has no clear
benefits, and we should thus move quickly to readiness for
deployment.

Andrew

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RE: [geo] Background-Greenland collapse

[Douglas MacMartin]

True that, whether one uses lots of CDR and/or SRM, it is possible that neither 
of those options would arrest mass loss without cooling beyond preindustrial, 
and that over the ensuing millennium we would eventually lose our coastal 
cities no matter what we do, but that we would delay that if we start solar geo 
sooner.  But (a) we don’t know and I think your second statement is correct, 
that we don’t have the modeling capability for that, (b) I’m more concerned 
about what we do in the next 50 years, myself, so questions of whether the 
cities are ultimately un-savable on timescales of centuries I don’t think 
matters for near-term decisions (c) personally I’m a lot more worried about 
Antarctic than Greenland, (d) nothing you said justifies your original claim 
(insofar as solar geo doesn’t guarantee keeping coastal cities over long 
timescales either).  I agree that starting solar geo today would result in less 
SLR by 2100 than not starting it, if emissions stayed the same, but the only 
thing we know in that sentence is the word “less”.

Your original claim was also based on the premise of throwing out all other 
options.  Yes, generally in any situation in life, if you refuse to consider 
all of the options but one, then yes, you have only one option.  That’s true, 
but only trivially.  Yes, if you rule out large-scale CDR to tackle historical 
emissions, then it is unequivocally true that SRM would be the only way to 
reduce temperatures beyond the current level.  That’s not exactly a profound 
observation…


From: Andrew Lockley 
Sent: Saturday, August 15, 2020 7:20 AM
To: Douglas MacMartin 
Cc: geoengineering 
Subject: Re: [geo] Background-Greenland collapse

The more advanced the process, the more momentum it has, and the harder it is 
to stop or reverse. It's unclear whether we could arrest mass loss, without 
driving the earth into a glacial period (colloquially, an ice age). I don't 
think there has been any serious modelling work done on ice loss reversal, or 
even if the models are capable of doing this with any useful accuracy.

On Sat, 15 Aug 2020, 12:03 Douglas MacMartin, 
mailto:dgm...@cornell.edu>> wrote:

What is not correct in the media report is this sentence: “This process, 
however, would take decades.”  Well, I guess arguably that’s true, it’s just it 
would take a LOT of decades.  Melt rate is currently of order 1-2mm/yr 
equivalent SLR, so to get the 6m from melting all of Greenland would take a few 
thousand years.  Obviously it can speed up a lot, but “hey, it’s losing mass” 
does not remotely imply “therefore we only have a few decades before we lose 
our coastal cities”.  So no, you can’t use this study to claim that 
geoengineering is required to keep our coastal cities.  The problem with 
relying on mitigation+CDR is time-scale, but this study doesn’t prove that our 
response time-scale needs to be faster than what CDR can (at least 
hypothetically) provide.
d
From: geoengineering@googlegroups.com 
mailto:geoengineering@googlegroups.com>> On 
Behalf Of Andrew Lockley
Sent: Saturday, August 15, 2020 3:40 AM
To: geoengineering 
mailto:geoengineering@googlegroups.com>>
Subject: [geo] Background-Greenland collapse

If this study is correct https://www.nature.com/articles/s43247-020-0001-2
And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3
Then it appears to back up a point that I have been making for a long time: 
geoengineering is required, if we are to keep our coastal cities. I do not see 
economic or political feasibility for large scale CDR to tackle historic 
emissions, and thus the task must fall to SRM.

Nobody has managed to rause an objection to this argument to date. I'd be 
grateful if those who might disagree were to raise counter arguments now.

If the situation is as I understand it, prevarication has no clear benefits, 
and we should thus move quickly to readiness for deployment.

Andrew


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Re: [geo] Background-Greenland collapse

[Andrew Lockley]

The more advanced the process, the more momentum it has, and the harder it
is to stop or reverse. It's unclear whether we could arrest mass loss,
without driving the earth into a glacial period (colloquially, an ice age).
I don't think there has been any serious modelling work done on ice loss
reversal, or even if the models are capable of doing this with any useful
accuracy.

On Sat, 15 Aug 2020, 12:03 Douglas MacMartin,  wrote:

> What is not correct in the media report is this sentence: “This process,
> however, would take decades.”  Well, I guess arguably that’s true, it’s
> just it would take a LOT of decades.  Melt rate is currently of order
> 1-2mm/yr equivalent SLR, so to get the 6m from melting all of Greenland
> would take a few thousand years.  Obviously it can speed up a lot, but
> “hey, it’s losing mass” does not remotely imply “therefore we only have a
> few decades before we lose our coastal cities”.  So no, you can’t use this
> study to claim that geoengineering is required to keep our coastal cities.
> The problem with relying on mitigation+CDR is time-scale, but this study
> doesn’t prove that our response time-scale needs to be faster than what CDR
> can (at least hypothetically) provide.
>
> d
>
> *From:* geoengineering@googlegroups.com  *On
> Behalf Of *Andrew Lockley
> *Sent:* Saturday, August 15, 2020 3:40 AM
> *To:* geoengineering 
> *Subject:* [geo] Background-Greenland collapse
>
>
>
> If this study is correct https://www.nature.com/articles/s43247-020-0001-2
>
> And is correctly reported here
> https://mobile.reuters.com/article/amp/idUSKCN25A2X3
>
> Then it appears to back up a point that I have been making for a long
> time: geoengineering is required, if we are to keep our coastal cities. I
> do not see economic or political feasibility for large scale CDR to tackle
> historic emissions, and thus the task must fall to SRM.
>
>
>
> Nobody has managed to rause an objection to this argument to date. I'd be
> grateful if those who might disagree were to raise counter arguments now.
>
>
>
> If the situation is as I understand it, prevarication has no clear
> benefits, and we should thus move quickly to readiness for deployment.
>
>
>
> Andrew
>
>
>
>
>
> --
> You received this message because you are subscribed to the Google Groups
> "geoengineering" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to geoengineering+unsubscr...@googlegroups.com.
> To view this discussion on the web visit
> https://groups.google.com/d/msgid/geoengineering/CAJ3C-07%2BJc0dmp26W2_H08Rsrs1V_sjEs1pkG6xuZZ75OcTa%2Bw%40mail.gmail.com
> 
> .
>

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RE: [geo] Background-Greenland collapse

[Douglas MacMartin]

What is not correct in the media report is this sentence: “This process, 
however, would take decades.”  Well, I guess arguably that’s true, it’s just it 
would take a LOT of decades.  Melt rate is currently of order 1-2mm/yr 
equivalent SLR, so to get the 6m from melting all of Greenland would take a few 
thousand years.  Obviously it can speed up a lot, but “hey, it’s losing mass” 
does not remotely imply “therefore we only have a few decades before we lose 
our coastal cities”.  So no, you can’t use this study to claim that 
geoengineering is required to keep our coastal cities.  The problem with 
relying on mitigation+CDR is time-scale, but this study doesn’t prove that our 
response time-scale needs to be faster than what CDR can (at least 
hypothetically) provide.
d
From: geoengineering@googlegroups.com  On 
Behalf Of Andrew Lockley
Sent: Saturday, August 15, 2020 3:40 AM
To: geoengineering 
Subject: [geo] Background-Greenland collapse

If this study is correct https://www.nature.com/articles/s43247-020-0001-2
And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3
Then it appears to back up a point that I have been making for a long time: 
geoengineering is required, if we are to keep our coastal cities. I do not see 
economic or political feasibility for large scale CDR to tackle historic 
emissions, and thus the task must fall to SRM.

Nobody has managed to rause an objection to this argument to date. I'd be 
grateful if those who might disagree were to raise counter arguments now.

If the situation is as I understand it, prevarication has no clear benefits, 
and we should thus move quickly to readiness for deployment.

Andrew


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[geo] Background-Greenland collapse

[Andrew Lockley]

If this study is correct https://www.nature.com/articles/s43247-020-0001-2
And is correctly reported here
https://mobile.reuters.com/article/amp/idUSKCN25A2X3
Then it appears to back up a point that I have been making for a long time:
geoengineering is required, if we are to keep our coastal cities. I do not
see economic or political feasibility for large scale CDR to tackle
historic emissions, and thus the task must fall to SRM.

Nobody has managed to rause an objection to this argument to date. I'd be
grateful if those who might disagree were to raise counter arguments now.

If the situation is as I understand it, prevarication has no clear
benefits, and we should thus move quickly to readiness for deployment.

Andrew

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