Stephen,
I agree with your suggested costs being < 1 billion dollars a year, given
the most expensive expectations. I do not know how the RS (2009) figures
were calculated for Marine Cloud Brightening.
A point though is that the cooling of the poles is very well achieved
by sub-tropical solar reflection. The meridional poleward heat transport
is a major way that the system affects the polar ice reduction. The
large sub tropical area of the reflective SC clouds means that the solar
energy into the system is vastly reduced. The role of the atmosphere in the
atmospheric heat engine is to transfer heat to the poles, where the ice
melting is an important feature. Thus the MCB increased large direct
reflection near the equator, directly affects polar ice melt in a
significant manner. This is an extra critical factor c.f. the
stratospheric sulphur process.
However, I would also agree with you that the increase in albedo near
the poles in the summer would make a significant contribution in the
cooling of the poles ... I also agree this is very important; but I would
like to emphasise that in spring, winter and autumn, a large cooling could
be achieved with sub tropical MCB.
Thanks
Alan
On Fri, 29 May 2015, Stephen Salter wrote:
Hi All
From http://en.wikipedia.org/wiki/Insolation the variation of solar
input with season and latitude should be
shown below.
[IMAGE]
At midsummer there is about 540 watts per square metre going in to the North
pole compared with 440 going in to the
equator. In addition, around the Arctic there is a very high fraction of low
cloud cover, 80 to 90 % compared with
around 25% and a much lower boundary layer, about 200 metres so that much less
air has to be treated with salt nuclei.
The only requirements for slowing ice melt are mobility of spray vessels and
movement of air or water in a northerly
direction.
I was a bit puzzled by Ken's mention of a few billion dollars a year for marine
cloud brightening and would like to
collect references on this. My own figures were based on index linking of the
cost of Flower class corvettes in WW II
which were build in similar numbers and suggest a few billion dollars for a
fleet which might last for 20 years or more.
Please can people send me any other cost estimates?
However we can agree that the costs are 'in the noise'.
Stephen
Emeritus Professor of Engineering Design. School of Engineering, University of
Edinburgh, Mayfield Road, Edinburgh EH9
3JL, Scotland [email protected], Tel +44 (0)131 650 5704, Cell 07795 203 195,
WWW.homepages.ed.ac.uk/shs, YouTube Jamie
Taylor Power for Change
On 28/05/2015 22:38, Ronal W. Larson wrote:
List cc Ken, John Nissen, Stephen Salter
Ken’s message re cloud brightening seems to be important . Maybe well known to
those close to the field, but I
found much new - especially between about 6 and 18 minutes in Part 4
( https://www.youtube.com/watch?v=b3D6mx5SQo8 ) . Nice to see credit give to
Stephen.
Dr. Neukermans and a very few others have done a lot of impressive work (as
volunteers). His speaking style I
found convincing (including all of video #3 - none on cloud brightening). I
liked that some unpromising approaches
were also described. Only a little new (but obviously well justified) money is
now being sought.
One question I pose on behalf of John Nissen and others in AMEG is why the
Arctic’s lack of sunlight (mentioned at
about the 18 minute mark) is critical. On an annual basis I believe the
insolation is about the world wide average
(as the sun doesn’t set for quite a few months). Not knowing enough on the
whole topic, this technical advance
would seem to be very good news for John/AMEG - if this Arctic solar issue can
still be on the table.
There are quite a few publications on this work, with a few of the most recent
at
https://www.researchgate.net/publication/260755971_Sub-micrometer_salt_aerosol_production_intended_for_marine_cloud_brig
htening
http://www.economist.com/news/science-and-technology/21635983-scientific-studies-techniques-deliberately-modifying-clima
te-are
http://articles.latimes.com/2014/mar/04/nation/la-na-climate-engineering-20140305/2
Ron
On May 28, 2015, at 9:04 AM, Ken Caldeira <[email protected]> wrote:
Five YouTube videos of the 12 May event are available here:
https://www.youtube.com/playlist?list=PL4E3D946BECCF7DE3
The event is described here:
http://www.sri.com/newsroom/events/cafe-scientifique-silicon-valley-sri-two-novel-approaches-mitigating-climate-change
Part 1: Ken on solar geo and strat aerosols:
https://www.youtube.com/watch?v=-Y6p-B-KbiQ
Part 2: Ken on solar geo and strat aerosols:
https://www.youtube.com/watch?v=wo5Y-SPrybE
Part 3: Armand on marine cloud brighening:
https://www.youtube.com/watch?v=ZbpYGwu4KNA
Part 4: Armand on marine cloud brighening:
https://www.youtube.com/watch?v=b3D6mx5SQo8
Part 5: Ken and Armand answer questions:
https://www.youtube.com/watch?v=9KS9Nbe3Wzs
Cafe Scientifique Silicon Valley @ SRI: Reflecting Sunlight to Cool
Earth's Climate: Emulating Volcanoes and
Brightening Marine Clouds
May 12, 2015
SRI - Menlo Park, CA
This free Cafe event will feature presentations by two thought leaders on
climate change:
Caldeira and Neukermans
Ken Caldeira (l); Armand Neukermans (r)
Solar Geoengineering and Climate Change: Nearly everyone understands that the
most effective way to reduce
environmental risk associated with climate change is to deeply cut greenhouse
gas emissions as soon as
possible, yet emissions and atmospheric concentrations of greenhouse gases
continue to increase. If current
emissions trends continue, by the end of this century, nearly every summer in
the tropics will be hotter than
the hottest summer yet on record, raising the possibility of widespread crop
failures and famine. If climate
change does prove truly catastrophic, the only feasible way to cool the Earth
rapidly would be to use solar
geoengineering technologies, for example, by emulating the cooling effects of
volcanoes. While it is fairly
certain that Earth's climate can be cooled in this way, it is far less certain
whether such approaches could
ever really reduce overall risk and damage. Dr. Ken Caldeira, a senior climate
scientist at the Carnegie
Institution for Science, will present the science of solar geoengineering and
discuss what this science might
mean for society.
Marine Cloud Brightening: The National Academy of Sciences recently called for
research into
“geoengineering“. Dr. Armand Neukermans will describe the efforts of a group of
retired scientists and
engineers to develop a spray system that might enable a study of the
feasibility of marine cloud brightening
(MCB) for climate cloud studies, as well as possible climate intervention. MCB
aims to increase the
reflectivity of low-hanging ocean clouds, thereby reflecting more sunlight and
cooling the planet. This might
be done by increasing the droplet concentration in the clouds by spraying
seawater from oceangoing ships. The
proposed systems aims to create 1015 cloud nuclei from a glass of seawater. MCB
( if ever needed) might
conceivably be used globally or locally (e.g., for arctic melt shielding,
hurricane cooling, reef
preservation, or fog belt restoration).
About the Speakers
Dr. Ken Caldeira is a climate scientist working for the Carnegie Institution
for Science, Department of
Global Ecology at Stanford University. He investigates issues related to
climate, carbon, and energy systems.
His primary tools are climate and the carbon cycle models, although he does
field work related to ocean
acidification. Dr. Caldeira co-authored a recent National Academies report,
Climate Intervention: Reflecting
Sunlight to Cool Earth. A free PDF version is available.
Dr. Armand Neukermans has held research and management positions at KLA-Tencor,
Hewlett-Packard, Xerox, and
General Electric, and founded Xros, an optical switch company. He is the author
of 40 publications and the
inventor of more than 75 patents in diverse fields. He was named Silicon Valley
“Inventor of the year” in
2001. Since his retirement, he has been involved in environmental projects,
such as the foundation of the Big
Sur Environmental Institute, and in fostering the causes of social
entrepreneurs. He holds EE and ME degrees
from Louvain University, and a Ph.D. in applied physics from Stanford
University.
- See more
at:http://www.sri.com/newsroom/events/cafe-scientifique-silicon-valley-sri-two-novel-approaches-mitigating-climate-change#s
thash.S562iCyX.dpuf
_______________
Ken Caldeira
Carnegie Institution for Science Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
+1 650 704 7212 [email protected]
website: http://dge.stanford.edu/labs/caldeiralab/
blog: http://kencaldeira.org
@KenCaldeira
My assistant is Dawn Ross <[email protected]>, with access to incoming
emails.
Postdoc positions:
https://jobs.carnegiescience.edu/jobs/postdoctoral-opportunity-global-climate-modeling/
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Alan Gadian, Senior Scientist, NCAS, Leeds University, LS2 9JT , UK
Email: [email protected] or [email protected]
Tel: (+44)/(0) 113 343 7246 Mobile: (+44)/(0) 775 451 9009
... Maths of Weather conference, 21st-24th Sept, ERQUY, France
... http://www.ncas.ac.uk/MOW2015
