Dear Stephan,
Congratulations on your recent prestigious and well deserved award. I
agree with you that the term SRM needs to be differentiated with Cloud
Brightening.
But I hope you recall that cloud brightening can be achieved in multiple
ways not just by increased sea salt aerosol. Our model simulations show
that enhanced DMS production via limited iron fertilization (0.2
femtomolar (1.0E-12 molar) iron to 1 femtomolar over 1 percent of the
South Pacific) could achieve greatly enhanced dimethyl sulfide
production and sulfate aerosol, the main precursor to CCN and cloud
brightening in the clean marine atmosphere. Especially, north of the
Southern Westerlies were it is greatly needed to keep or restore the
southward shift and intensification of these winds.
Oliver
On 3/23/2012 5:37 PM, John Latham wrote:
Hello Michael,
Interesting scenario.
Yes, I'm aware of the efficient ice-nucleating properties of biological
aerosol.
I'm not sure, however, whether you have in mind
the role of ice in increasing outgoing LW radiation
or decreasing SW radiation.
Either way it's important to decide which type of cloud you wish to
modify - unless you propose creating clouds.
Seeding clouds with ice nuclei can prolong or reduce their lifetimes,
according to the amount of seeding. The fastest growth of ice in clouds
occurs when both ice and supercooled water coexist (in the same regions,
with much more of the latter than the former).
Before you write a proposal it's vital to determine whether the processes
involved are consistent with the (surprisingly tricky) cloud physics.
Good Luck, John.
John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: [email protected] or [email protected]
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: Michael Hayes [[email protected]]
Sent: Friday, March 23, 2012 9:21 PM
To: [email protected]
Cc: John Latham; [email protected]; [email protected]
Subject: Re: [geo] Re: Why exclusive focus on Sulphur?
Dr. Latham et al.,
After you submitted the HydeTellerWood paper last year, it did change many of
my concepts.
I have been working upon a possible concept criteria which could guide current
and future efforts. So far, I have only a few design criterion's.
1) Places a high value on social/political acceptance.
2) Have a high degree of environmental interface reaction down to the 3rd order
effects.
3) Be adjustable to seasonal/regional/special situational (political)
conditions.
4) Have positive ancillary social/environmental benefits.
As far as I know, we have no available work on nor consensus of concept design
value(s). Unfortunately, we are still in a stage which concepts are championed
by individuals under values they themselves promote. There is nothing
inherently wrong with that, however the developement of theiretical design
values would help on a number of different important levels.
The concept of large scale Geophysical Management Science (GeMS) is only
starting and there will be many concepts put forth. How do we 'judge' them?
Here is an example: Pseudomonas syringae
http://en.wikipedia.org/wiki/Pseudomonas_syringae
"Ice nucleating properties
P. syringae, more than any mineral or other organism, is responsible for the surface frost damage in
plants<http://en.wikipedia.org/wiki/Frost#Effect_on_plants>,[8]<http://en.wikipedia.org/wiki/Pseudomonas_syringae#cite_note-7>
exposed to the environment. P. syringae can cause water to freeze at temperatures as high as -1.8 °C (28.8
°F),[9]<http://en.wikipedia.org/wiki/Pseudomonas_syringae#cite_note-8> but strains causing ice
nucleation<http://en.wikipedia.org/wiki/Nucleation> at lower temperatures (down to -8°C) are more
common.[10]<http://en.wikipedia.org/wiki/Pseudomonas_syringae#cite_note-Chapter4-9> The freezing causes
injuries in the epithelia and makes the nutrients in the underlying plant tissues available to the
bacteria.[citation needed<http://en.wikipedia.org/wiki/Wikipedia:Citation_needed>]
P. syringae have ina (ice nucleation-active) genes that make Ina proteins which translocate to
the outer bacterial cell wall<http://en.wikipedia.org/wiki/Cell_wall> on the surface of
the bacteria where the Ina proteins act as nuclei for ice
formation.[10]<http://en.wikipedia.org/wiki/Pseudomonas_syringae#cite_note-Chapter4-9>
Artificial strains of P. syringae known as ice-minus
bacteria<http://en.wikipedia.org/wiki/Ice-minus_bacteria> have been created to reduce
frost damage.
P. syringae have been found in the center of hailstones, suggesting that the bacterium may
play a role in Earth's hydrological
cycle.[5]<http://en.wikipedia.org/wiki/Pseudomonas_syringae#cite_note-BBC25May2011-4>"
If a proposal were put forth using this as a key technology, how can we
accurately/objectively compare it to all others?
Michael
On Wed, Mar 21, 2012 at 2:17 PM, Ken
Caldeira<[email protected]<mailto:[email protected]>>
wrote:
I think there have been two main reasons for focus on sulfur, at least for the
stratosphere:
1. It can be released as a gas (SO2 or H2S) that can then oxidize to form
particles of approximately the right size, greatly reducing problems of
dispersion upon release.
2. Volcanoes did it and it worked. We may be able to be about as intelligent as
a volcano.
_______________
Ken Caldeira
Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
+1 650 704 7212<tel:%2B1%20650%20704%207212>
[email protected]<mailto:[email protected]>
http://dge.stanford.edu/labs/caldeiralab @kencaldeira
YouTube:
<http://www.youtube.com/watch?v=a9LaYCbYCxo>Climate change and the transition from
coal to low-carbon electricity<http://www.youtube.com/watch?v=a9LaYCbYCxo>
Crop yields in a geoengineered
climate<http://www.youtube.com/watch?v=-0LCXNoIu-c>
On Wed, Mar 21, 2012 at 7:30 PM, John
Latham<[email protected]<mailto:[email protected]>>
wrote:
Hello All,
I am probably missing a crucial point or two - if so please
correct me - but I am failing to understand the current almost
absolute focus on sulphur as a seeding agent.
In the case of stratospheric seeding the case for sulphur seeding
is of course strong, but even then it seems worthwhile to have a
serious look at alternatives. The attached comprehensive and
authoritative paper by Rod Hyde, Lowell Wood& Edward Teller
provides such an examination with rigorous physical understanding.
At the least, we need to know what alternatives exist in case
some problem arises with the use of sulphur aerosol.
In the case of tropospheric seeding with sulphur, as has already
been said, the public reaction is likely to be violently adverse.So
it seems vital to ask why this is the approach that so many people
seem to be advocating - or at least considering much more fully
than alternatives. Unfortunately I do not have the requisite
knowledge to name such, except to raise the possibility that
seawater aerosol seeding (which is of course central to the
in-cloud MCB idea) could also be used for out-of-cloud
tropospheric seeding. It is likely to be much more benign
than tropospheric sulphur seeding.
All Best, John.
John Latham
Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000
Email: [email protected]<mailto:[email protected]> or
[email protected]<mailto:[email protected]>
Tel: (US-Work) 303-497-8182<tel:303-497-8182> or (US-Home)
303-444-2429<tel:303-444-2429>
or (US-Cell) 303-882-0724<tel:303-882-0724> or (UK) 01928-730-002
http://www.mmm.ucar.edu/people/latham
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