[geo] RE: Marine Cloud Brightening for the Southern Ocean

[SALTER Stephen]

Hi All

Ye gives welcome and rare support for work on marine cloud brightening but it 
is not quite accurate to say ‘real-time hurricane management’. If you want to 
moderate a hurricane tomorrow you are much too late.  You should have started 
last November and recorded the trajectory of sea surface temperatures along the 
path of the hurricane breeding oceans so as to get the pattern requested by 
Governments of hurricane affect countries in the spraying contract. You should 
aim to get this done by the start of the next hurricane season. Tropical storms 
provide useful rainfall so we should moderate rather than prevent. It would 
also be wise to avoid blame for the choice of temperature!
Ye is quite right to identify spray generation as a key problem.  Andreas 
Tsiamis has done a useful COMSOL multi-physics simulation of drop generation 
using the Stevenson sandwich nozzle design. He has numbers for pressure, drop 
frequency and drop diameter as a function of nozzle size. There were a small 
number of coalescence events leading to double-volume drops but these were 
removed with a one bar modulation at the drop frequency.  The results are in 
close agreement with the paper by van Hoeve at 
https://doi.org/10.1063/1.3524533. Camelia Dunare has used contact printing to 
etch the sandwich nozzles down to twice the diameter we need and is confident 
that the higher resolution of optical printing will get to the smaller nozzles 
needed. Engineering drawings for the housing of 200 mm are complete except for 
the high-frequency pressure excitation needed for mono-disperse spray and 
avoidance of the Aitken mode. The remaining problem is that while silicon has 
sufficient tensile stress it is also extremely notch sensitive. The 
instrumentation needed to measure spray size in the laboratory is quite 
expensive but we may be able to get access to the life savings of a gullible 
old-age pensioner. Drawings and design calculations for much of the rest of the 
vessel have reached the stage where they could go to potential sub-contractors.
Ye also mentions the intermittency of wind used for power generation.  Data 
from the trade-wind regions and southern oceans are encouraging and the sea is 
an excellent heat integrator.  We do not need exact day-by-day cooling.  We 
want a low dose over a wide area so changes of wind direction are welcome. It 
might be desirable to spray under clear skies into air masses which will later 
move to regions with higher relative humidity.  Being able to choose time and 
place (and stop at short notice) is welcome but cooling next week is soon 
enough.
It is unfortunate that ignorance of a new field is so often used as an argument 
to prevent funding of research that might remove that ignorance. Perhaps this 
is the result of career anxiety by timid administrators.

Breathe safely

Stephen Salter
Emeritus Professor of Engineering Design
School of Engineering
Mayfield Road
Edinburgh EH9 3DW
0131 650 5704
https://www.youtube.com/watch?v=o-0h14RFq4M=155s
https://www.youtube.com/watch?v=0BBVTStBrhw
https://www.youtube.com/watch?v=ZBB6WtH_Ni8



From: Ye Tao 
Sent: Friday, March 4, 2022 9:30 AM
To: Robert Tulip ; 'Planetary Restoration' 
; 'geoengineering' 
; 'healthy-planet-action-coalition' 
; 
hpac-steering-cir...@googlegroups.com; noac-meeti...@googlegroups.com; 'pfieko' 
; 'Ron Baiman' ; SALTER Stephen 
; 'Peter Wadhams' 
Subject: Re: Marine Cloud Brightening for the Southern Ocean

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.

Dear Robert,

Thanks for directing attention and effort to SRM, away from carbon capture 
fantasies that distract and harm.

I support funding MCB research of the wind-powered type proposed by Stephen.  
This is because MCB using fossil-fuel ships is counterproductive due to 
unsustainable fuel consumption requirements.  The chemically benign nature and 
better spatial resolution of sea salt MCB are a couple of the many important 
advantages over SAI.  Another important application is real-time flood and 
hurricane management, something no other SRM approach seems capable of.

A central challenge in the way to realizing Stephen's wind-powered proposal is 
the development of an energy-efficient system for seawater droplet production 
at the required monodispersity, sub-micron size, and flux.If these 
parameters cannot be simultaneously satisfied, several orders of magnitude 
increase in deployment energy and material costs would result.  So there is 
substantial uncertainty, after what will certainly be a multi-decade research 
program, on if such a system could be invented and developed.

Another challenge is wind intermittency and its high-frequency directional 
changes.  Their impact on the achievable duty cycle of a single vessel and the 
resulting areal coverage efficiency have not been taken into account in 
existing 

Re: [EXTERNAL] [geo] Re: Marine Cloud Brightening for the Southern Ocean

[Jonathan Marshall]

Australia is also well placed to build upon its existing. and long term. 
support for more fossil fuels, and a technology neutral position which always 
means encouraging more fossil fuels and the release of massive amounts of 
GHG

jon
___
From: geoengineering@googlegroups.com  on 
behalf of rob...@rtulip.net 
Sent: Friday, 4 March 2022 2:32 PM
To: 'Planetary Restoration'; 'geoengineering'; 
'healthy-planet-action-coalition'; hpac-steering-cir...@googlegroups.com; 
noac-meeti...@googlegroups.com; 'Ye Tao'; 'pfieko'; 'Ron Baiman'; 'Stephen 
Salter'
Subject: [EXTERNAL] [geo] Re: Marine Cloud Brightening for the Southern Ocean

As Daniel mentioned, Australia is well placed to build upon its existing 
support<https://www.nature.com/articles/d41586-021-02290-3> for marine cloud 
brightening for the Great Barrier Reef.

Australia could seek international agreement to test MCB in international 
waters, working with scientists and governments.  Deployment would aim to 
mitigate factors that have accentuated unstable weather in Australia.

Paul Beckwith provided this explanation of possible MCB technology - 
https://paulbeckwith.net/2021/06/20/autonomous-spray-ship-deployment-to-cool-planet-via-marine-cloud-brightening/<https://paulbeckwith.net/2021/06/20/autonomous-spray-ship-deployment-to-cool-planet-via-marine-cloud-brightening/>

Robert Tulip


From: 
planetary-restorat...@googlegroups.com<mailto:planetary-restorat...@googlegroups.com>
 
mailto:planetary-restorat...@googlegroups.com>>
 On Behalf Of Daniel Kieve
Sent: Friday, 4 March 2022 11:55 AM
To: Robert Tulip mailto:rtulip2...@yahoo.com.au>>
Cc: Planetary Restoration 
mailto:planetary-restorat...@googlegroups.com>>;
 geoengineering 
mailto:geoengineering@googlegroups.com>>; 
healthy-planet-action-coalition 
mailto:healthy-planet-action-coalit...@googlegroups.com>>;
 
hpac-steering-cir...@googlegroups.com<mailto:hpac-steering-cir...@googlegroups.com>;
 noac-meeti...@googlegroups.com<mailto:noac-meeti...@googlegroups.com>; Ye Tao 
mailto:t...@rowland.harvard.edu>>; pfieko 
mailto:pfi...@gmail.com>>; Ron Baiman 
mailto:rpbai...@gmail.com>>; Stephen Salter 
mailto:s.sal...@ed.ac.uk>>
Subject: Re: Marine Cloud Brightening for the Southern Ocean

Hi All,

As Robert says, given the geopolitical situation, a focus on direct cooling of 
the Antarctic ( via MCB in the Southern Oceans) makes perfect sense as opposed 
to the Arctic. With the Australian Government's existing support for Marine 
Cloud Brightening to help save the Great Barrier Reef, we'd be hitting the 
ground running ( relatively speaking).

Also, focus on MCB tech which only uses seawater / seasalt also maķes sense,  
given the evidence of its overwhelmingly benign likely effects ( if 
administered carefully) and the PR & political challenges associated with 
adding any substance to the atmosphere for geoengineering purposes.

Kind regards,

Daniel

On Thu, 3 Mar 2022, 22:24 'Robert Tulip' via Healthy Planet Action Coalition, 
mailto:healthy-planet-action-coalit...@googlegroups.com>>
 wrote:
Dear Ye, Peter, Ron, Stephen and all

I would like to ask the Australian Government to investigate methods to 
increase planetary albedo.  This is something the G20 should have on its agenda.

My view is that cooling the Southern Ocean using Marine Cloud Brightening 
should be a first topic to discuss for international agreement.  This would 
cool Antarctica, our planetary refrigerator, and appears likely to be able to 
mitigate sea ice melt, glacier collapse, the warming of ocean currents, extreme 
weather and biodiversity loss.  Antarctica might be an easier place to start 
than the Arctic in view of the geopolitics.

Ye, further to your comments below, it would be good for all methods to 
increase albedo to be studied.  I agree somewhat with your doubts regarding 
stratospheric aerosol injection (atmospheric chemistry uncertainties, acid rain 
risks, ocean ecosystem impacts, and inhibition of renewable transition) and 
could add ozone and hydroxyl effects as specific atmospheric chemistry 
concerns. For marine cloud brightening my assessment is that all of these 
effects are likely to be overwhelmingly benign, with significant positive 
benefits.  The atmospheric chemistry and rain distribution questions are likely 
to be primary.  MCB could be the simplest and safest and cheapest initial way 
to produce rapid cooling and mitigation of extreme weather.

I don’t accept that enabling a slower renewable transition is a big problem for 
the climate.  The effect on radiative forcing of cutting fossil fuel use can 
only be far smaller than the effects of direct albedo increase. It  is 
essential to use SRM to cut radiative forcing to buy time to mitigate extreme 
weather while CDR ramps up.   Emission reduction is likely to remain marginal 
to planetary cooling compared to SRM and CDR.

[geo] Re: Marine Cloud Brightening for the Southern Ocean

[robert]

As Daniel mentioned, Australia is well placed to build upon its existing 
support   for marine cloud 
brightening for the Great Barrier Reef.  

 

Australia could seek international agreement to test MCB in international 
waters, working with scientists and governments.  Deployment would aim to 
mitigate factors that have accentuated unstable weather in Australia.   

 

Paul Beckwith provided this explanation of possible MCB technology - 
https://paulbeckwith.net/2021/06/20/autonomous-spray-ship-deployment-to-cool-planet-via-marine-cloud-brightening/

 

Robert Tulip

 

 

From: planetary-restorat...@googlegroups.com 
  
mailto:planetary-restorat...@googlegroups.com> > On Behalf Of Daniel Kieve
Sent: Friday, 4 March 2022 11:55 AM
To: Robert Tulip mailto:rtulip2...@yahoo.com.au> >
Cc: Planetary Restoration mailto:planetary-restorat...@googlegroups.com> >; geoengineering 
mailto:geoengineering@googlegroups.com> >; 
healthy-planet-action-coalition 
mailto:healthy-planet-action-coalit...@googlegroups.com> >; 
hpac-steering-cir...@googlegroups.com 
 ; noac-meeti...@googlegroups.com 
 ; Ye Tao mailto:t...@rowland.harvard.edu> >; pfieko mailto:pfi...@gmail.com> >; Ron Baiman mailto:rpbai...@gmail.com> >; Stephen Salter mailto:s.sal...@ed.ac.uk> >
Subject: Re: Marine Cloud Brightening for the Southern Ocean

 

Hi All,

 

As Robert says, given the geopolitical situation, a focus on direct cooling of 
the Antarctic ( via MCB in the Southern Oceans) makes perfect sense as opposed 
to the Arctic. With the Australian Government's existing support for Marine 
Cloud Brightening to help save the Great Barrier Reef, we'd be hitting the 
ground running ( relatively speaking).

 

Also, focus on MCB tech which only uses seawater / seasalt also maķes sense,  
given the evidence of its overwhelmingly benign likely effects ( if 
administered carefully) and the PR & political challenges associated with 
adding any substance to the atmosphere for geoengineering purposes. 

 

Kind regards,

 

Daniel

 

On Thu, 3 Mar 2022, 22:24 'Robert Tulip' via Healthy Planet Action Coalition, 
mailto:healthy-planet-action-coalit...@googlegroups.com> > wrote:

Dear Ye, Peter, Ron, Stephen and all

 

I would like to ask the Australian Government to investigate methods to 
increase planetary albedo.  This is something the G20 should have on its agenda.

 

My view is that cooling the Southern Ocean using Marine Cloud Brightening 
should be a first topic to discuss for international agreement.  This would 
cool Antarctica, our planetary refrigerator, and appears likely to be able to 
mitigate sea ice melt, glacier collapse, the warming of ocean currents, extreme 
weather and biodiversity loss.  Antarctica might be an easier place to start 
than the Arctic in view of the geopolitics.

 

Ye, further to your comments below, it would be good for all methods to 
increase albedo to be studied.  I agree somewhat with your doubts regarding 
stratospheric aerosol injection (atmospheric chemistry uncertainties, acid rain 
risks, ocean ecosystem impacts, and inhibition of renewable transition) and 
could add ozone and hydroxyl effects as specific atmospheric chemistry 
concerns. For marine cloud brightening my assessment is that all of these 
effects are likely to be overwhelmingly benign, with significant positive 
benefits.  The atmospheric chemistry and rain distribution questions are likely 
to be primary.  MCB could be the simplest and safest and cheapest initial way 
to produce rapid cooling and mitigation of extreme weather.  

 

I don’t accept that enabling a slower renewable transition is a big problem for 
the climate.  The effect on radiative forcing of cutting fossil fuel use can 
only be far smaller than the effects of direct albedo increase. It  is 
essential to use SRM to cut radiative forcing to buy time to mitigate extreme 
weather while CDR ramps up.   Emission reduction is likely to remain marginal 
to planetary cooling compared to SRM and CDR. This is an important moral 
question regarding the strategic justification for geoengineering.  Slowing the 
renewable transition is a good thing to bring on board communities and states 
who now support traditional energy sources.

 

Sea salt is a safe natural product whose cooling effect can be cheaply 
optimised using the methods described by Stephen Salter. I would hope that only 
when NaCl is accepted as a good way to improve atmospheric chemistry should 
nations consider deploying atmospheric iron and sulphur, recognising that the 
scientific case for both is quite strong.

 

Robert Tulip

 

 

 

From: healthy-planet-action-coalit...@googlegroups.com 
  
mailto:healthy-planet-action-coalit...@googlegroups.com> > On Behalf Of Ye Tao
Sent: 

[geo] Re: Marine Cloud Brightening

[Michael MacCracken]

Hi Clive--

Because the Sun is only up in the Arctic for a few months during the 
year, there is no need to have the aerosol stay up through the whole 
year--and in the winter the stratosphere gets so cold that the particles 
contribute to ozone depletion, so one does not want to be increasing the 
particle concentrations in winter. But doing so in the spring (probably 
only needed in the months after the surface snow starts to melt) and 
early summer when sunlight is strong, has the potential to increase the 
albedo.


And yes, in the troposphere, particles are primarily removed by 
precipitation, but that really is only mainly occurring where there is 
convection, and for convection to occur, the surface has to be quite 
warm adn the atmosphere unstable. While that occurs in lower latitudes, 
in the Arctic as it comes out of winter, convection is not normally 
occurring, so particles injected there into the upper troposphere, 
assuming the circulation does not take them out of the region (and 
predictions of this could be used to determine when and where it would 
be optimal to make or not make an aerosol injection), won't get removed 
by precipitation (coalesence and condensation of water vapor might lead 
to particles growing so large they fall out of the atmosphere, but that 
is generally a slow process and so the lifetime of the particles might 
stretch out for several weeks, reducing how much has to be injected to 
keep a certain loading).


And one reason of increased effectiveness of the reduction of sunlight 
(calculated, as I recall, in the case I did as amount of effect per 
amount of aerosol needed) in these latitudes is a result of doing the 
reduction right where the snow and (sea) ice albedo feedbacks are 
strongest, so just as warming leads to an amplified warming in the high 
latitudes, so will a reduction in warming lead to an amplified effect.


So, a lot would need to be considered to put together an operational 
plan, but, thinking a bit idealistically about only the physics and 
engineering of it, conceptually possible, at least in my view.


Mike



On 1/30/22 7:34 AM, Clive Elsworth wrote:
But John is saying they could cool the Arctic with SAI injected 
/below/ the stratosphere.



On 30/01/2022 12:09 SALTER Stephen  wrote:


Clive

There is not much rain in the stratosphere where SO2 will be injected.

Stephen.

*From:* healthy-planet-action-coalit...@googlegroups.com 
 *On Behalf Of 
*Clive Elsworth

*Sent:* Sunday, January 30, 2022 11:59 AM
*To:* SALTER Stephen 
*Cc:* Ron Baiman ; Sev Clarke ; 
Peter Wadhams ; Chris Vivian 
; H simmens ; John 
Nissen ; Robert Tulip 
; geoengineering 
; Planetary Restoration 
; Shaun Fitzgerald 
; Hugh.Hunt ; Daphne Wysham 
; healthy-planet-action-coalition 
; Dermott Reilly 


*Subject:* RE: Marine Cloud Brightening


*This email was sent to you by someone outside the University.*

You should only click on links or attachments if you are certain that 
the email is genuine and the content is safe.


Stephen


As I understand it SO2 gets rained out more readily than CFCs, which 
eventually drift into the stratosphere. CFCs are stable in the 
troposphere and only get destroyed in the stratosphere by the more 
intense UV.



Clive

On 30/01/2022 09:50 SALTER Stephen  wrote:



Clive

How do you think that stuff got up to the Ozone hole?

Stephen

*From:* healthy-planet-action-coalit...@googlegroups.com
 *On Behalf Of
*Clive Elsworth
*Sent:* Saturday, January 29, 2022 11:22 PM
*To:* SALTER Stephen 
*Cc:* Ron Baiman ; Sev Clarke
; Peter Wadhams ;
Chris Vivian ; H simmens
; John Nissen ;
Robert Tulip ; geoengineering
; Planetary Restoration
; Shaun Fitzgerald
; Hugh.Hunt ; Daphne Wysham
; healthy-planet-action-coalition
; Dermott
Reilly 
*Subject:* Marine Cloud Brightening


*This email was sent to you by someone outside the University.*

You should only click on links or attachments if you are certain
that the email is genuine and the content is safe.

Stephen


I confess I'm not sufficiently familiar with atmospheric physics
to say whether aerosol particles released under the Arctic
stratosphere would substantially move up into it.


Either way, Marine Cloud Brightening seems the safer option to me
for the reasons you have given on numerous occasions. The
question is if it can be ready in time and with sufficient social
license.


I think you're aware of the University of Washington's MCB work:
https://faculty.washington.edu/robwood2/wordpress/?page_id=954


The video on that page is high quality and only about a month
old. I wonder if some collaboration might help speed things up?


Clive


On 29/01/2022 21:03 SALTER Stephen  wrote:



Clive

Here is something about the Brewer Dobson velocity.

Stephen

-- 
You received this message because you are subscribed to 

[geo] RE: Marine Cloud Brightening

[SALTER Stephen]

Clive
Yes but if the life is shorter you need more aircraft.
Stephen

From: healthy-planet-action-coalit...@googlegroups.com 
 On Behalf Of Clive Elsworth
Sent: Sunday, January 30, 2022 12:35 PM
To: SALTER Stephen 
Cc: Ron Baiman ; Sev Clarke ; Peter 
Wadhams ; Chris Vivian ; 
H simmens ; John Nissen ; Robert 
Tulip ; geoengineering 
; Planetary Restoration 
; Shaun Fitzgerald ; 
Hugh.Hunt ; Daphne Wysham ; 
healthy-planet-action-coalition 
; Dermott Reilly 

Subject: RE: Marine Cloud Brightening

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.
But John is saying they could cool the Arctic with SAI injected below the 
stratosphere.

On 30/01/2022 12:09 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive
There is not much rain in the stratosphere where SO2 will be injected.
Stephen.

From: 
healthy-planet-action-coalit...@googlegroups.com
 
mailto:healthy-planet-action-coalit...@googlegroups.com>>
 On Behalf Of Clive Elsworth
Sent: Sunday, January 30, 2022 11:59 AM
To: SALTER Stephen mailto:s.sal...@ed.ac.uk>>
Cc: Ron Baiman mailto:rpbai...@gmail.com>>; Sev Clarke 
mailto:sevcla...@me.com>>; Peter Wadhams 
mailto:peter.wadh...@gmail.com>>; Chris Vivian 
mailto:chris.vivi...@btinternet.com>>; H simmens 
mailto:hsimm...@gmail.com>>; John Nissen 
mailto:johnnissen2...@gmail.com>>; Robert Tulip 
mailto:rtulip2...@yahoo.com.au>>; geoengineering 
mailto:geoengineering@googlegroups.com>>; 
Planetary Restoration 
mailto:planetary-restorat...@googlegroups.com>>;
 Shaun Fitzgerald mailto:sd...@cam.ac.uk>>; Hugh.Hunt 
mailto:he...@cam.ac.uk>>; Daphne Wysham 
mailto:dap...@methaneaction.org>>; 
healthy-planet-action-coalition 
mailto:healthy-planet-action-coalit...@googlegroups.com>>;
 Dermott Reilly 
mailto:dermott.rei...@nanolandglobal.com>>
Subject: RE: Marine Cloud Brightening

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.
Stephen

As I understand it SO2 gets rained out more readily than CFCs, which eventually 
drift into the stratosphere. CFCs are stable in the troposphere and only get 
destroyed in the stratosphere by the more intense UV.

Clive
On 30/01/2022 09:50 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive
How do you think that stuff got up to the Ozone hole?
Stephen

From: 
healthy-planet-action-coalit...@googlegroups.com
 
mailto:healthy-planet-action-coalit...@googlegroups.com>>
 On Behalf Of Clive Elsworth
Sent: Saturday, January 29, 2022 11:22 PM
To: SALTER Stephen mailto:s.sal...@ed.ac.uk>>
Cc: Ron Baiman mailto:rpbai...@gmail.com>>; Sev Clarke 
mailto:sevcla...@me.com>>; Peter Wadhams 
mailto:peter.wadh...@gmail.com>>; Chris Vivian 
mailto:chris.vivi...@btinternet.com>>; H simmens 
mailto:hsimm...@gmail.com>>; John Nissen 
mailto:johnnissen2...@gmail.com>>; Robert Tulip 
mailto:rtulip2...@yahoo.com.au>>; geoengineering 
mailto:geoengineering@googlegroups.com>>; 
Planetary Restoration 
mailto:planetary-restorat...@googlegroups.com>>;
 Shaun Fitzgerald mailto:sd...@cam.ac.uk>>; Hugh.Hunt 
mailto:he...@cam.ac.uk>>; Daphne Wysham 
mailto:dap...@methaneaction.org>>; 
healthy-planet-action-coalition 
mailto:healthy-planet-action-coalit...@googlegroups.com>>;
 Dermott Reilly 
mailto:dermott.rei...@nanolandglobal.com>>
Subject: Marine Cloud Brightening

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.
Stephen

I confess I'm not sufficiently familiar with atmospheric physics to say whether 
aerosol particles released under the Arctic stratosphere would substantially 
move up into it.

Either way, Marine Cloud Brightening seems the safer option to me for the 
reasons you have given on numerous occasions. The question is if it can be 
ready in time and with sufficient social license.

I think you're aware of the University of Washington's MCB work: 
https://faculty.washington.edu/robwood2/wordpress/?page_id=954

The video on that page is high quality and only about a month old. I wonder if 
some collaboration might help speed things up?

Clive

On 29/01/2022 21:03 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive

Here is something about the Brewer Dobson velocity.

Stephen

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[geo] Re: Marine Cloud Brightening

[Michael MacCracken]

Dear Stephen--The atmospheric transport of gases and aerosols differs. 
For gases, atmospheric mixing dominates any consideration of different 
molecular weights up to altitudes of five to ten tens of kilometers. For 
aerosols, their mass and size introduce a fall rate that, depending on 
size, generally takes over in the upper troposphere/lower stratosphere, 
so say by ten kilometers or so. So CFCs get up to the stratospheric 
ozone layer by atmospheric mixing, generally in air in low latitudes. 
Getting aerosols into the stratosphere (unless they are chemically 
formed there, such as in the stratospheric ozone hole region) generally 
takes some sort of major injection mechanism like a volcanic eruption 
(or very major firestorm).


Mike

On 1/30/22 4:50 AM, SALTER Stephen wrote:


Clive

How do you think that stuff got up to the Ozone hole?

Stephen

*From:* healthy-planet-action-coalit...@googlegroups.com 
 *On Behalf Of 
*Clive Elsworth

*Sent:* Saturday, January 29, 2022 11:22 PM
*To:* SALTER Stephen 
*Cc:* Ron Baiman ; Sev Clarke ; 
Peter Wadhams ; Chris Vivian 
; H simmens ; John 
Nissen ; Robert Tulip 
; geoengineering 
; Planetary Restoration 
; Shaun Fitzgerald 
; Hugh.Hunt ; Daphne Wysham 
; healthy-planet-action-coalition 
; Dermott Reilly 


*Subject:* Marine Cloud Brightening

*This email was sent to you by someone outside the University.*

You should only click on links or attachments if you are certain that 
the email is genuine and the content is safe.


Stephen

I confess I'm not sufficiently familiar with atmospheric physics to 
say whether aerosol particles released under the Arctic stratosphere 
would substantially move up into it.


Either way, Marine Cloud Brightening seems the safer option to me for 
the reasons you have given on numerous occasions. The question is if 
it can be ready in time and with sufficient social license.


I think you're aware of the University of Washington's MCB work: 
https://faculty.washington.edu/robwood2/wordpress/?page_id=954


The video on that page is high quality and only about a month old. I 
wonder if some collaboration might help speed things up?


Clive

On 29/01/2022 21:03 SALTER Stephen  wrote:

Clive

Here is something about the Brewer Dobson velocity.

Stephen

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[geo] RE: Marine Cloud Brightening

[SALTER Stephen]

Clive
There is not much rain in the stratosphere where SO2 will be injected.
Stephen.

From: healthy-planet-action-coalit...@googlegroups.com 
 On Behalf Of Clive Elsworth
Sent: Sunday, January 30, 2022 11:59 AM
To: SALTER Stephen 
Cc: Ron Baiman ; Sev Clarke ; Peter 
Wadhams ; Chris Vivian ; 
H simmens ; John Nissen ; Robert 
Tulip ; geoengineering 
; Planetary Restoration 
; Shaun Fitzgerald ; 
Hugh.Hunt ; Daphne Wysham ; 
healthy-planet-action-coalition 
; Dermott Reilly 

Subject: RE: Marine Cloud Brightening

This email was sent to you by someone outside the University.
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Stephen

As I understand it SO2 gets rained out more readily than CFCs, which eventually 
drift into the stratosphere. CFCs are stable in the troposphere and only get 
destroyed in the stratosphere by the more intense UV.

Clive
On 30/01/2022 09:50 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive
How do you think that stuff got up to the Ozone hole?
Stephen

From: 
healthy-planet-action-coalit...@googlegroups.com
 
mailto:healthy-planet-action-coalit...@googlegroups.com>>
 On Behalf Of Clive Elsworth
Sent: Saturday, January 29, 2022 11:22 PM
To: SALTER Stephen mailto:s.sal...@ed.ac.uk>>
Cc: Ron Baiman mailto:rpbai...@gmail.com>>; Sev Clarke 
mailto:sevcla...@me.com>>; Peter Wadhams 
mailto:peter.wadh...@gmail.com>>; Chris Vivian 
mailto:chris.vivi...@btinternet.com>>; H simmens 
mailto:hsimm...@gmail.com>>; John Nissen 
mailto:johnnissen2...@gmail.com>>; Robert Tulip 
mailto:rtulip2...@yahoo.com.au>>; geoengineering 
mailto:geoengineering@googlegroups.com>>; 
Planetary Restoration 
mailto:planetary-restorat...@googlegroups.com>>;
 Shaun Fitzgerald mailto:sd...@cam.ac.uk>>; Hugh.Hunt 
mailto:he...@cam.ac.uk>>; Daphne Wysham 
mailto:dap...@methaneaction.org>>; 
healthy-planet-action-coalition 
mailto:healthy-planet-action-coalit...@googlegroups.com>>;
 Dermott Reilly 
mailto:dermott.rei...@nanolandglobal.com>>
Subject: Marine Cloud Brightening

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.
Stephen

I confess I'm not sufficiently familiar with atmospheric physics to say whether 
aerosol particles released under the Arctic stratosphere would substantially 
move up into it.

Either way, Marine Cloud Brightening seems the safer option to me for the 
reasons you have given on numerous occasions. The question is if it can be 
ready in time and with sufficient social license.

I think you're aware of the University of Washington's MCB work: 
https://faculty.washington.edu/robwood2/wordpress/?page_id=954

The video on that page is high quality and only about a month old. I wonder if 
some collaboration might help speed things up?

Clive

On 29/01/2022 21:03 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive

Here is something about the Brewer Dobson velocity.

Stephen

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[geo] RE: Marine Cloud Brightening

[SALTER Stephen]

Clive
How do you think that stuff got up to the Ozone hole?
Stephen

From: healthy-planet-action-coalit...@googlegroups.com 
 On Behalf Of Clive Elsworth
Sent: Saturday, January 29, 2022 11:22 PM
To: SALTER Stephen 
Cc: Ron Baiman ; Sev Clarke ; Peter 
Wadhams ; Chris Vivian ; 
H simmens ; John Nissen ; Robert 
Tulip ; geoengineering 
; Planetary Restoration 
; Shaun Fitzgerald ; 
Hugh.Hunt ; Daphne Wysham ; 
healthy-planet-action-coalition 
; Dermott Reilly 

Subject: Marine Cloud Brightening

This email was sent to you by someone outside the University.
You should only click on links or attachments if you are certain that the email 
is genuine and the content is safe.
Stephen

I confess I'm not sufficiently familiar with atmospheric physics to say whether 
aerosol particles released under the Arctic stratosphere would substantially 
move up into it.

Either way, Marine Cloud Brightening seems the safer option to me for the 
reasons you have given on numerous occasions. The question is if it can be 
ready in time and with sufficient social license.

I think you're aware of the University of Washington's MCB work: 
https://faculty.washington.edu/robwood2/wordpress/?page_id=954

The video on that page is high quality and only about a month old. I wonder if 
some collaboration might help speed things up?

Clive

On 29/01/2022 21:03 SALTER Stephen 
mailto:s.sal...@ed.ac.uk>> wrote:


Clive

Here is something about the Brewer Dobson velocity.

Stephen

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Re: [geo] Re: Marine cloud brightening coagulation comment - ACPD

[Stephen Salter]

Hi All

This paper raises some interesting questions.

They are using drop sizes from 10 nanometres to 10 microns.  We hope get 
as close to a mono-disperse spray of 0.8 microns as is possible.  If 
drag and inertia of drops are close, the relative velocities due to 
local turbulence will be low and collisions less frequent.   What would 
be the coagulation rates with a much narrower spread of drop diameters?


We also propose to give drops a negative electrostatic charge.  How will 
this affect coagulation?


If the coagulation rate varies with conditions, do they change slowly 
for the spray vessels to be moved to better places?


Stephen

On 20/09/2014 00:02, Andrew Lockley wrote:

Poster's note : The original paper (which should have been posted
first) is here:

http://www.atmos-chem-phys.net/13/10385/2013/acp-13-10385-2013.html

Reduced efficacy of marine cloud brightening geoengineering due to
in-plume aerosol coagulation: parameterization and global implications
G. S. Stuart1, R. G. Stevens1, A.-I. Partanen3, A. K. L. Jenkins2, H.
Korhonen3, P. M. Forster2, D. V. Spracklen2, and J. R. Pierce1,4

Abstract
The intentional enhancement of cloud albedo via controlled sea-spray
injection from ships (marine cloud brightening) has been proposed as a
possible method to control anthropogenic global warming; however,
there remains significant uncertainty in the efficacy of this method
due to, amongst other factors, uncertainties in aerosol and cloud
microphysics. A major assumption used in recent cloud- and
climate-modeling studies is that all sea spray was emitted uniformly
into some oceanic grid boxes, and thus these studies did not account
for subgrid aerosol coagulation within the sea-spray plumes. We
explore the evolution of these sea-salt plumes using a multi-shelled
Gaussian plume model with size-resolved aerosol coagulation. We
determine how the final number of particles depends on meteorological
conditions, including wind speed and boundary-layer stability, as well
as the emission rate and size distribution of aerosol emitted. Under
previously proposed injection rates and typical marine conditions, we
find that the number of aerosol particles is reduced by over 50%, but
this reduction varies from under 10% to over 90% depending on the
conditions. We provide a computationally efficient parameterization
for cloud-resolving and global-scale models to account for
subgrid-scale coagulation, and we implement this parameterization in a
global-scale aerosol-climate model. While designed to address
subgrid-scale coagulation of sea-salt particles, the parameterization
is generally applicable for coagulation of subgrid-scale aerosol from
point sources. We find that accounting for this subgrid-scale
coagulation reduces cloud droplet number concentrations by 46% over
emission regions, and reduces the global mean radiative flux
perturbation from −1.5 W m−2 to −0.8 W m−2.

Citation: Stuart, G. S., Stevens, R. G., Partanen, A.-I., Jenkins, A.
K. L., Korhonen, H., Forster, P. M., Spracklen, D. V., and Pierce, J.
R.: Reduced efficacy of marine cloud brightening geoengineering due to
in-plume aerosol coagulation: parameterization and global
implications, Atmos. Chem. Phys., 13, 10385-10396,
doi:10.5194/acp-13-10385-2013, 2013.

On 15 September 2014 22:21, Andrew Lockley andrew.lock...@gmail.com wrote:

Attached





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[geo] Re: Marine Cloud Brightening pros cons. Alan Robock criteria

[Alan Robock]

Dear John,

We are designing an MCB GeoMIP experiment so we can see how robust the 
results are from the climate models that have already done these 
experiments, but all differently.  In theory, there would be both 
benefits and risks, and these must be quantified.  From my list, you can 
cross our ozone depletion, no more blue skies and effects on remote 
sensing and astronomy, as well as other stratosphere-specific issues.  
But I think it is premature to claims that MCB would be safe and 
effective.  And detailed indoor computer modeling experiments will be 
needed to provide an environmental impact statement for outdoor 
experiments.  Indeed, a lot more research is needed.


Alan

Alan Robock, Distinguished Professor
  Editor, Reviews of Geophysics
  Director, Meteorology Undergraduate Program
  Associate Director, Center for Environmental Prediction
Department of Environmental Sciences  Phone: +1-848-932-5751
Rutgers University  Fax: +1-732-932-8644
14 College Farm Road   E-mail: rob...@envsci.rutgers.edu
New Brunswick, NJ 08901-8551  USA  http://envsci.rutgers.edu/~robock
   http://twitter.com/AlanRobock

On 6/3/13 4:56 AM, John Latham wrote:

To-: [rob...@envsci.rutgers.edu];[geoengineering@googlegroups.com]
From:-   [lat...@ucar.edu]

Hello Alan  Colleagues,

Yes, as  when convenient it would be interesting, Alan, to learn from you 
which of your 26 objections to stratospheric seeding apply to Marine Cloud 
Brightening (MCB): and, of course whether there are additional ones pertaining to 
MCB, which do not apply to the sulphur idea.
Consideration of MCB has not been evident in the recent plethora of blog 
submissions, so I would like to provide a list of its associated positive and 
negative qualities which  - in my view, on balance – provide a convincing case 
for being one of the SRM techniques to be selected for research support.

1.Computations from several top-class models agree in concluding that MCB – if 
it works – could maintain the Earth’s average surface temperature and the 
sea-ice coverage at both poles at roughly the current values, at least up to 
the CO2-doubling point.

2.Development of a system for spraying adequate quantities of sea-water aerosol 
is not yet fully achieved, but recent developments indicate a high likelihood 
of success.

3.Ship-tracks provide hard evidence of the capacity of aerosol to brighten 
clouds, but it does not follow that it can be achieved on the spatial scale 
required.

4. GCM computations indicate in one case that MCB deployment would produce 
unacceptable rainfall reduction in Amazonia, whereas in two other studies that 
is not so. Further work shows that the Amazonian rainfall loss can be 
eliminated by not seeding in a particular region. Provisionally, it seems 
possible that adverse rainfall effects can be avoided by judicious choice of 
seeding locations.

5.We have designed a three-phase field-test of MCB, based heavily on the 
larger, highly successful International VOCALS study, in which several members 
of our team played leading roles. Its scale would be about 100 km by 100 km, 
which seems too small to influence climate. Such a test would not be conducted 
without appropriate authorization. Please see reference below.

6. In principle, MCB is capable of being usefully applied on spatial scales 
much less than global. A paper on the utilization of MCB to weaken hurricanes 
was published in 2012 (see below). Another, on the protection of coral reefs 
has just been accepted. In both cases the idea is to reduce ocean surface water 
temperatures in appropriate oceanic areas.

Best Wishes, John.

10.  John Latham, Keith Bower, Tom Choularton, Hugh Coe, Paul Connolly, Gary 
Cooper,Tim Craft, Jack Foster,  Alan Gadian, Lee Galbraith, Hector Iacovides, David 
Johnston, Brian Launder, Brian Leslie, John Meyer, Armand   Neukermans, Bob Ormond, 
Ben Parkes, Philip Rasch, John Rush, Stephen Salter, Tom Stevenson, Hailong Wang, 
Qin Wang  Rob Wood, 2012, Marine Cloud Brightening, Phil.Trans.Roy. Soc. A . 
2012, 370, 4217-4262. doi: 10.1098/rsta.2012.0086

12.John Latham, Ben Parkes, Alan Gadian,Stephen Salter, 2012.
Weakening of Hurricanes via Marine Cloud Brightening (MCB),
Atmospheric Science Letters, DOI: 10.1002/asl.402







John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: lat...@ucar.edu  or john.latha...@manchester.ac.uk
Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429
  or   (US-Cell)   303-882-0724  or (UK) 01928-730-002
http://www.mmm.ucar.edu/people/latham

From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on 
behalf of Alan Robock [rob...@envsci.rutgers.edu]
Sent: 01 June 2013 18:03
To: geoengineering@googlegroups.com
Subject: Re: [geo] NASA Ames meeting

Dear Stephen,

My list of 26 problems is in slide 157 of

RE: [geo] Re: Marine Cloud Brightening pros cons. Alan Robock criteria

[John Latham]

Hello again Alan,

I agree entirely with your comments below, and look forward to 
learning the results of yr assessment.

All Best,John.



John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: lat...@ucar.edu  or john.latha...@manchester.ac.uk
Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429
 or   (US-Cell)   303-882-0724  or (UK) 01928-730-002
http://www.mmm.ucar.edu/people/latham

From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on 
behalf of Alan Robock [rob...@envsci.rutgers.edu]
Sent: 03 June 2013 17:09
To: John Latham
Cc: geoengineering@googlegroups.com
Subject: [geo] Re: Marine Cloud Brightening pros  cons. Alan Robock criteria

Dear John,

We are designing an MCB GeoMIP experiment so we can see how robust the
results are from the climate models that have already done these
experiments, but all differently.  In theory, there would be both
benefits and risks, and these must be quantified.  From my list, you can
cross our ozone depletion, no more blue skies and effects on remote
sensing and astronomy, as well as other stratosphere-specific issues.
But I think it is premature to claims that MCB would be safe and
effective.  And detailed indoor computer modeling experiments will be
needed to provide an environmental impact statement for outdoor
experiments.  Indeed, a lot more research is needed.

Alan

Alan Robock, Distinguished Professor
   Editor, Reviews of Geophysics
   Director, Meteorology Undergraduate Program
   Associate Director, Center for Environmental Prediction
Department of Environmental Sciences  Phone: +1-848-932-5751
Rutgers University  Fax: +1-732-932-8644
14 College Farm Road   E-mail: rob...@envsci.rutgers.edu
New Brunswick, NJ 08901-8551  USA  http://envsci.rutgers.edu/~robock
http://twitter.com/AlanRobock

On 6/3/13 4:56 AM, John Latham wrote:
 To-: [rob...@envsci.rutgers.edu];[geoengineering@googlegroups.com]
 From:-   [lat...@ucar.edu]

 Hello Alan  Colleagues,

 Yes, as  when convenient it would be interesting, Alan, to learn from you 
 which of your 26 objections to stratospheric seeding apply to Marine Cloud 
 Brightening (MCB): and, of course whether there are additional ones 
 pertaining to MCB, which do not apply to the sulphur idea.
 Consideration of MCB has not been evident in the recent plethora of blog 
 submissions, so I would like to provide a list of its associated positive and 
 negative qualities which  - in my view, on balance – provide a convincing 
 case for being one of the SRM techniques to be selected for research support.

 1.Computations from several top-class models agree in concluding that MCB – 
 if it works – could maintain the Earth’s average surface temperature and the 
 sea-ice coverage at both poles at roughly the current values, at least up to 
 the CO2-doubling point.

 2.Development of a system for spraying adequate quantities of sea-water 
 aerosol is not yet fully achieved, but recent developments indicate a high 
 likelihood of success.

 3.Ship-tracks provide hard evidence of the capacity of aerosol to brighten 
 clouds, but it does not follow that it can be achieved on the spatial scale 
 required.

 4. GCM computations indicate in one case that MCB deployment would produce 
 unacceptable rainfall reduction in Amazonia, whereas in two other studies 
 that is not so. Further work shows that the Amazonian rainfall loss can be 
 eliminated by not seeding in a particular region. Provisionally, it seems 
 possible that adverse rainfall effects can be avoided by judicious choice of 
 seeding locations.

 5.We have designed a three-phase field-test of MCB, based heavily on the 
 larger, highly successful International VOCALS study, in which several 
 members of our team played leading roles. Its scale would be about 100 km by 
 100 km, which seems too small to influence climate. Such a test would not be 
 conducted without appropriate authorization. Please see reference below.

 6. In principle, MCB is capable of being usefully applied on spatial scales 
 much less than global. A paper on the utilization of MCB to weaken hurricanes 
 was published in 2012 (see below). Another, on the protection of coral reefs 
 has just been accepted. In both cases the idea is to reduce ocean surface 
 water temperatures in appropriate oceanic areas.

 Best Wishes, John.

 10.  John Latham, Keith Bower, Tom Choularton, Hugh Coe, Paul Connolly, Gary 
 Cooper,Tim Craft, Jack Foster,  Alan Gadian, Lee Galbraith, Hector Iacovides, 
 David Johnston, Brian Launder, Brian Leslie, John Meyer, Armand   Neukermans, 
 Bob Ormond, Ben Parkes, Philip Rasch, John Rush, Stephen Salter, Tom 
 Stevenson, Hailong Wang, Qin Wang  Rob Wood, 2012, Marine Cloud Brightening, 
 Phil.Trans.Roy. Soc. A . 2012, 370, 4217-4262. doi: 10.1098/rsta.2012.0086

 12.John Latham, Ben Parkes, Alan

[geo] RE: Marine Cloud Brightening pros cons. Alan Robock criteria

[John Latham]

Hello Olaf,

I should have mentioned that, re hurricanes  coral, our idea is to 
maintain the SST's in the appropriate areas at current values, 
using MCB to counter CO2 increase.

Trying to reduce SSTs below current values is a different
and possibly dangerous game, which we are not considering.

John.


John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: lat...@ucar.edu  or john.latha...@manchester.ac.uk
Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429
 or   (US-Cell)   303-882-0724  or (UK) 01928-730-002
http://www.mmm.ucar.edu/people/latham

From: Schuiling, R.D. (Olaf) [r.d.schuil...@uu.nl]
Sent: 03 June 2013 13:14
To: John Latham; rob...@envsci.rutgers.edu; geoengineering@googlegroups.com
Subject: RE: Marine Cloud Brightening pros  cons. Alan Robock criteria

Is there not a problem about reduction of photosynthesis, particularly for 
polar plankton? Olaf Schuiling

-Original Message-
From: geoengineering@googlegroups.com [mailto:geoengineering@googlegroups.com] 
On Behalf Of John Latham
Sent: maandag 3 juni 2013 13:56
To: rob...@envsci.rutgers.edu; geoengineering@googlegroups.com
Subject: [geo] Marine Cloud Brightening pros  cons. Alan Robock criteria


To-: [rob...@envsci.rutgers.edu];[geoengineering@googlegroups.com]
From:-   [lat...@ucar.edu]

Hello Alan  Colleagues,

Yes, as  when convenient it would be interesting, Alan, to learn from you 
which of your 26 objections to stratospheric seeding apply to Marine Cloud 
Brightening (MCB): and, of course whether there are additional ones pertaining 
to MCB, which do not apply to the sulphur idea.
Consideration of MCB has not been evident in the recent plethora of blog 
submissions, so I would like to provide a list of its associated positive and 
negative qualities which  - in my view, on balance - provide a convincing case 
for being one of the SRM techniques to be selected for research support.

1.Computations from several top-class models agree in concluding that MCB - if 
it works - could maintain the Earth's average surface temperature and the 
sea-ice coverage at both poles at roughly the current values, at least up to 
the CO2-doubling point.

2.Development of a system for spraying adequate quantities of sea-water aerosol 
is not yet fully achieved, but recent developments indicate a high likelihood 
of success.

3.Ship-tracks provide hard evidence of the capacity of aerosol to brighten 
clouds, but it does not follow that it can be achieved on the spatial scale 
required.

4. GCM computations indicate in one case that MCB deployment would produce 
unacceptable rainfall reduction in Amazonia, whereas in two other studies that 
is not so. Further work shows that the Amazonian rainfall loss can be 
eliminated by not seeding in a particular region. Provisionally, it seems 
possible that adverse rainfall effects can be avoided by judicious choice of 
seeding locations.

5.We have designed a three-phase field-test of MCB, based heavily on the 
larger, highly successful International VOCALS study, in which several members 
of our team played leading roles. Its scale would be about 100 km by 100 km, 
which seems too small to influence climate. Such a test would not be conducted 
without appropriate authorization. Please see reference below.

6. In principle, MCB is capable of being usefully applied on spatial scales 
much less than global. A paper on the utilization of MCB to weaken hurricanes 
was published in 2012 (see below). Another, on the protection of coral reefs 
has just been accepted. In both cases the idea is to reduce ocean surface water 
temperatures in appropriate oceanic areas.

Best Wishes, John.

10.  John Latham, Keith Bower, Tom Choularton, Hugh Coe, Paul Connolly, Gary 
Cooper,Tim Craft, Jack Foster,  Alan Gadian, Lee Galbraith, Hector Iacovides, 
David Johnston, Brian Launder, Brian Leslie, John Meyer, Armand   Neukermans, 
Bob Ormond, Ben Parkes, Philip Rasch, John Rush, Stephen Salter, Tom Stevenson, 
Hailong Wang, Qin Wang  Rob Wood, 2012, Marine Cloud Brightening, 
Phil.Trans.Roy. Soc. A . 2012, 370, 4217-4262. doi: 10.1098/rsta.2012.0086

12.John Latham, Ben Parkes, Alan Gadian,Stephen Salter, 2012.
Weakening of Hurricanes via Marine Cloud Brightening (MCB), Atmospheric Science 
Letters, DOI: 10.1002/asl.402







John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: lat...@ucar.edu  or john.latha...@manchester.ac.uk
Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429
 or   (US-Cell)   303-882-0724  or (UK) 01928-730-002
http://www.mmm.ucar.edu/people/latham

From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on 
behalf of Alan Robock [rob...@envsci.rutgers.edu]
Sent: 01 June 2013 18:03
To: geoengineering@googlegroups.com
Subject: Re: [geo] NASA Ames meeting

Dear Stephen,

My list of 26 problems is in slide 157 of

RE: [geo] Re: Marine Cloud Brightening pros cons. Alan Robock criteria

[Doug MacMartin]

Hi Stephen,

 

Did you or Ben conduct a signal to noise analysis for this?  (Sorry, I
haven't read his thesis, nor walked through quantitative analysis myself.)
When we did our testing paper a few years back, we found that a global-scale
forcing of 1 W/m^2 would still take decades to get adequate signal to noise
ratio on precipitation effects on an area the size of India, for example.
If you forced 2% of the surface area with 50 W/m^2, the time taken I'd think
would be of the same order.  Maybe this isn't a big problem in a model one
can run for centuries, and if the result is robust across multiple models,
one might have some confidence in it.  But harder still (that is, need more
information) if you want to also identify how things depend on the month of
forcing, for example.  There's no magic inherent in a pseudo-random signal,
simply the ability to generate many uncorrelated sequences so you can test
multiple locations with the same model run (if the frequency response was
flat, you could do the same by using a different forcing frequency at each
location, for example).

 

Testing paper is here: MacMynowski, D. G., Keith, D., Caldeira, K., and
Shin, H.-J., Can we test geoengineering?
http://pubs.rsc.org/en/Content/ArticleLanding/2011/EE/c1ee01256h  Energy
and Environmental Science, 4(12), pp 5044-5052, 2011.

 

doug

 

-Original Message-
From: geoengineering@googlegroups.com
[mailto:geoengineering@googlegroups.com] On Behalf Of Stephen Salter
Sent: Monday, June 03, 2013 11:06 AM
To: geoengineering@googlegroups.com
Subject: Re: [geo] Re: Marine Cloud Brightening pros  cons. Alan Robock
criteria

 

Dear Alan

 

I was pleased to hear that you will be looking at marine cloud 

brightening and look forward to seeing your results.  I attach a note on 

an idea which might be able to get an everywhere-to-everywhere transfer 

function of all the effects. The first results from Ben Parkes show the 

intriguing result that spray from the Aleutian islands can reverse the 

drying effects in the Amazon caused  by spray off Namibia.  Can you 

offer any suggestions about causes of cross-hemisphere influence ?

 

I hope that modellers will be able to use the idea and vary spray time 

and place in the light of the phase of monsoons and el Nino.

 

Stephen

 

 

 

On 03/06/2013 17:09, Alan Robock wrote:

 Dear John,

 

 We are designing an MCB GeoMIP experiment so we can see how robust the 

 results are from the climate models that have already done these 

 experiments, but all differently.  In theory, there would be both 

 benefits and risks, and these must be quantified.  From my list, you 

 can cross our ozone depletion, no more blue skies and effects on 

 remote sensing and astronomy, as well as other stratosphere-specific 

 issues.  But I think it is premature to claims that MCB would be safe 

 and effective.  And detailed indoor computer modeling experiments will 

 be needed to provide an environmental impact statement for outdoor 

 experiments.  Indeed, a lot more research is needed.

 

 Alan

 

 Alan Robock, Distinguished Professor

   Editor, Reviews of Geophysics

   Director, Meteorology Undergraduate Program

   Associate Director, Center for Environmental Prediction

 Department of Environmental Sciences  Phone: +1-848-932-5751

 Rutgers University  Fax: +1-732-932-8644

 14 College Farm Road   E-mail:
mailto:rob...@envsci.rutgers.edu rob...@envsci.rutgers.edu

 New Brunswick, NJ 08901-8551  USA  http://envsci.rutgers.edu/~robock
http://envsci.rutgers.edu/~robock

  http://twitter.com/AlanRobock http://twitter.com/AlanRobock

 

 On 6/3/13 4:56 AM, John Latham wrote:

 To-: [rob...@envsci.rutgers.edu];[geoengineering@googlegroups.com]

 From:-   [lat...@ucar.edu]

 

 Hello Alan  Colleagues,

 

 Yes, as  when convenient it would be interesting, Alan, to learn 

 from you which of your 26 objections to stratospheric seeding apply 

 to Marine Cloud Brightening (MCB): and, of course whether there are 

 additional ones pertaining to MCB, which do not apply to the sulphur 

 idea.

 Consideration of MCB has not been evident in the recent plethora of 

 blog submissions, so I would like to provide a list of its associated 

 positive and negative qualities which  - in my view, on balance - 

 provide a convincing case for being one of the SRM techniques to be 

 selected for research support.

 

 1.Computations from several top-class models agree in concluding that 

 MCB - if it works - could maintain the Earth's average surface 

 temperature and the sea-ice coverage at both poles at roughly the 

 current values, at least up to the CO2-doubling point.

 

 2.Development of a system for spraying adequate quantities of 

 sea-water aerosol is not yet fully achieved, but recent developments 

 indicate a high likelihood of success.

 

 3.Ship-tracks provide hard evidence of the capacity of aerosol to 

 brighten