Alan
Pollution is a loaded word. Check out
http://www.healthandcare.co.uk/great-gifts/salitair-salt-therapy.html?gclid=CNKH0-ur864CFdISfAodwHUpNA
for evidence that breathing salt is very good for people with lung
diseases. Osmosis is just as effective as anti-biotics at killing bugs
but harmless to large organisms The amount of salt we need to offset
the thermal effects of double pre-industrial CO2 is about 1% of what is
put up now by waves breaking on the beach.
Stephen
Emeritus Professor of Engineering Design
Institute for Energy Systems
School of Engineering
Mayfield Road
University of Edinburgh EH9 3JL
Scotland
Tel +44 131 650 5704
Mobile 07795 203 195
www.see.ed.ac.uk/~shs
On 19/03/2012 16:03, Alan Robock wrote:
Dear Mike,
I don't know how you do this 6 to 1 calculation. We found that the
e-folding time for stratospheric aerosols in the Arctic s 2-4 months,
with 4 months in the summer, the relevant time. (see
http://climate.envsci.rutgers.edu/pdf/2008JD010050small.pdf ) If we
compare this to the lifetime of tropospheric aerosols, on week, and
add a week to the 4 months for their tropospheric time, the ratio is
130 days to 7 days, which is *19 to 1, not 6 to 1*. Furthermore, the
health effects of additional tropospheric pollution are not
acceptable, in my opinion.
Alan
[On sabbatical for current academic year. The best way to contact me
is by email,rob...@envsci.rutgers.edu, or at 732-881-1610 (cell).]
Alan Robock, Professor II (Distinguished Professor)
Editor, Reviews of Geophysics
Director, Meteorology Undergraduate Program
Associate Director, Center for Environmental Prediction
Department of Environmental Sciences Phone: +1-732-932-9800 x6222
Rutgers University Fax: +1-732-932-8644
14 College Farm Road E-mail:rob...@envsci.rutgers.edu
New Brunswick, NJ 08901-8551 USAhttp://envsci.rutgers.edu/~robock
On 3/18/2012 5:49 PM, Mike MacCracken wrote:
Hi Stephen--My wording must have been confusing.
For stratospheric injections at low latitudes, the lifetime is 1-2 years.
The aerosols do move poleward and are carried into the troposphere in mid
and high latitudes. This is one approach to trying to limit global climate
change, and, as David Keith says, studies indicate that these cool the polar
regions, though perhaps not in the stratosphere.
Your cloud brightening approach is also to limit global warming. I'd also
suggest that we could offset some of the global warming by sulfate aerosols
out over vast ocean areas instead of sulfate's present dominance over, now,
southeastern Asia, China, etc.--so keeping or modestly enhancing the present
cooling offset. [And reducing cirrus may also be a viable approach.]
A third approach is to cool the poles (and this might be good for regional
purposes alone), but cooling also pulls heat out of lower latitudes and
helps to cool them somewhat. The Caldeira-Wood shows it works conceptually
(they reduced solar constant) and Robock et al. injected SO2 into
stratosphere to do (but the full year injection of SO2/SO4 likely spread
some to lower latitudes and the monsoons were affected). One thing Robock et
al. found was that the lifetime of sulfate in the polar stratosphere is
about two months, and so that means that the potential 100 to 1 advantage of
stratospheric sulfate is not valid, and we're down to 6 to 1 compared to
surface-based approaches such as CCN or microbubbles to cool incoming
waters, sulfate or something similar over Arctic area, surface brightening
by microbubbles, etc.--noting that such approaches are only needed (and
effective) for the few months per year when the Sun is well up in the sky.
As David Keith also says, there is a lot of research to be done to determine
which approaches or alone or in different variants might work, or be
effective or ineffective and have unintended consequences, much less how
such an approach or set of approaches might be integrated with mitigation,
adaptation, suffering, etc.
Best, Mike MacCracken
On 3/18/12 12:52 PM, "Stephen Salter"<s.sal...@ed.ac.uk> wrote:
Mike
I had thought that the plan was stratospheric aerosol to be released at
low latitudes and would slowly migrate to the poles where is would
gracefully descend. If you can be sure that it will all have gone in 10
days then my concerns vanish. But if the air cannot get through the
water surface how can the aerosol it carries get there? It will form a
blanket even if it is a very low one.
A short life would mean that we do not have to worry about methane
release. But can we do enough to cool the rest of the planet? Perhaps
Jon Egil can tell us about blanket lifetime.
Stephen
Mike MacCracken wrote:
The Robock et al simulations of an Arctic injection found that the lifetime
of particles in the lower Arctic stratosphere was only two months. In that
one would only need particles up during the sunlit season (say three months,
for only really helps after the sea ice surface has melted and the sun is
high in the sky). During the relatively calm weather of Arctic summer, the
lifetime of tropospheric sulfate, for example<kcalde...@carnegie.stanford.edu>
wrote:
That is just misleading. The third attachment is a top-of-atmosphere
radiation balance on the email I am responding to shows shortwave radiation.
The attached figure shows the corresponding temperature field from the same
simulation for the same time period. Note Arctic cooling.
Also, we should not focus on individual regional blobs of color in an
average
of a single decade from a single simulation.
The paper these figures came from is here:
http://www.atmos-chem-phys.net/10/5999/2010/acp-10-5999-2010.pdf
_______________
Ken Caldeira
Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
+1 650 704 7212kcalde...@carnegie.stanford.edu
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 Sat, Mar 17, 2012 at 1:31 PM, Andrew Lockley<and...@andrewlockley.com>
wrote:
Hi
Here are some model outputs which Stephen sent me. These appear to show
localized arctic warming in geoengineering simulations. This could be due
to
winter effects.
I assume this is the source for the controversial figure in the BBC quote
A
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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