I am thinking of how to get funding for in-lab Evaluation of Tetra Ethyl
Silicate Dissolved in Aviation Kerosene As a Means of Distributing
Stratospheric Aerosols for Geoenginering.
The two points below are relevant to this discussion but a bit muddled as this
is a rehash of my submission to the Royal Society
1)Possible Advantages of Silica.
Particle size. At these submicron sizes it is the size of the particle which
defines the wavelength of light which is reflected/diffracted. There have been
several papers, which have pointed out the difficulty of controlling sulphuric
acid droplet size and the problem of agglomeration of the droplets. (Papers
include that by Tilmes/Robock in the Royal Society's Philosophical Transactions)
It seems logical that the concentration of Tetra ethyl silicate in aviation
fuel would define the size of silica particles produced on burning. If so, the
particle size could be selected for maximum reduction in net radiation. There
would then be less material and fewer particles/droplets for the same level of
global cooling.
2)The most likely first application of a stratospheric aerosol sunscreen is
that proposed by Gregory Benfold "Saving the Arctic".
Combined with the aircraft distribution system, the proposal would be to spread
the aerosol by aircraft flying between 40 and 60,000 ft. from the time of first
Arctic daylight (April approximately) until late July approximately.
Ideally for very long stratospheric life, aerosols need to be injected at about
80,000 ft. If they are only injected at 50,000 ft. they will fall out of the
atmosphere in about three months. (Ken Caldera's lecture available on U tube).
In this case that is exactly what we want so that they would fall out by the
end of the Arctic summer and would not be present during the winter --.
Most of the arguments that aerosols will damage the ozone layer
assume that the aerosols are injected high in the stratosphere for long life.
In this case most of the injection would not reach the ozone layer. In
addition the aerosols would no longer be present in winter when the effect is
greatest.
It seems very likely that implementation of this type would succeed
in "saving the Arctic". In particular the target would be to eliminate
significant melting of the Greenland ice sheet or sudden loss of parts of it.
The same principle could then be applied to Antarctica.
The target should be zero sea level rise. If this could be
achieved the saving in costs of construction, relocating populations and lives
lost in flood disasters would be absolutely enormous.
john Gorman
ps this is a really good discussion -by everyone.
----- Original Message -----
From: Andrew Lockley
To: John Nissen
Cc: Alvia Gaskill ; [email protected] ; [email protected] ;
[email protected] ; [email protected] ; [email protected]
; [email protected] ; [email protected] ; [email protected]
Sent: Sunday, May 10, 2009 1:01 AM
Subject: [geo] Re: Balancing the pros and cons of geoengineering
Can't we modify the aerosol size, and deployment patterns, to make sure they
fall out quickly and don't go anywhere near India?
A
2009/5/9 John Nissen <[email protected]>
Very good discussion.
I'm trying to get a balance of pros (benefits B1-B7) and cons (specific
fears S1-S21). What I'd like out of our discussion is some kind of risk
assessment for the possible downside of a weaker monsoon, as this is considered
the biggest risk in the regional effects (S1). And we could make this
reasonably pessimistic, to be on the safe side - i.e. be cautious with the
application of geoengineering. On the other hand, we might be able to reduce
this risk, e.g. by neutralising sulphate aerosol; if there's a good chance of
this working, then we can factor that into the calculation. Or the risk might
be offset by a benefit in that region, e.g. improved summer water supply from
Himalayan glaciers?
So, what kind of impact would a weaker monsoon (ISM) have on India? What
is the probability of stratospheric aerosols deployed in the Arctic would
produce a weaker monsoon? Can this risk be significantly countered? Can it be
significantly offset?
Note that the risk on benefit side might be measured in terms of a risk,
without geoengineering, of millions or even billions of lives being lost
(especially if massive methane release adds several degrees of global warming,
B4). Alternatively we could measure in GDP lost - current global GDP (aka GWP)
is about $60 trillion I believe.
Cheers,
John
----- Original Message ----- From: "Alvia Gaskill" <[email protected]>
To: <[email protected]>; <[email protected]>
Cc: <[email protected]>; "Andrew Lockley"
<[email protected]>; <[email protected]>; <[email protected]>;
<[email protected]>; <[email protected]>;
<[email protected]>; <[email protected]>
Sent: Saturday, May 09, 2009 4:50 PM
Subject: Re: [geo] Re: Balancing the pros and cons of geoengineering
Stephen makes a good point that leads to a more general one. If there
are precipitation reductions associated with sunlight blocking schemes,
consideration should also be given to mitigating these, analogous to the
medications given to patients with Type II diabetes to combat the side effects
of the primary drug.
This is an oversimplification, but the way summer monsoons work is that
in the summer the land gets warmer than the ocean faster, creating a low
pressure area and this causes on shore flow as air moves from high to low
presssure. For some reason, Laki caused this to be muted. There were no
aerosols from Laki over India and it has been suggested there was a
teleconnected response (see the paper Stephen attached) although in paleo
climate the authors say the effects were direct, but don't give specifics. In
the case of Pinatubo, both the land and sea were cooled by the aerosol and the
land simply didn't heat up fast enough to generate the on shore flow.
If the Arctic only aerosol geoengineering does cause a reduction in the
ISM (Indian Summer Monsoon as there are other monsoons that affect India, but
this is the most important one), use of the cloud whitening to restore at least
some of the temperature differential should be considered. Likewise, in a
global aerosol scheme, with a global aerosol spread similar to that of
Pinatubo, the cloud whitening could also be used to create a temperature
differential, but at some point it becomes a race to the bottom, with the land
temperature simply too cool to initiate the low pressure area. In this case,
reducing the depth of the aerosol layer over the land may be the most effective
way to restore the dynamics.
I previously suggested using ammonia released from either planes or
balloons to react with the sulfate aerosol and drop them out as ammonium
sulfate. This idea as well as Stephen's could be applied to other locations
such as the Amazon, Eastern China and Africa where models indicate unacceptable
reductions in precipitation are a result of either aerosol geoengineering or
global warming. Of course, the ammonia wouldn't be of any value in a global
warming/no aerosol scenario.
I said in one the earliest papers I wrote on geoengineering that
eventually we were going to have to learn how to manipulate the climate to our
advantage. That includes both gross scale and fine tuning.
In a related issue, last year I posted a link from a group in the UK that
was carrying out some 130 different models of aerosol geoengineering. It was a
volunteer effort among universities. If they have done even a fraction of the
modeling, this work should be taken into account in designing new studies such
as Rutgers is proposing. Anyone have an update?
You may recall also that we spent some time last year discussing the
significance of the "little brown blotches" in absolute terms and now Ken also
raises the issue of their resolution.
http://en.wikipedia.org/wiki/Monsoon
Monsoons are caused by the larger amplitude of the seasonal cycle of land
temperature compared to that of nearby oceans. This differential warming
happens because heat in the ocean is mixed vertically through a "mixed layer"
that may be fifty meters deep, through the action of wind and
buoyancy-generated turbulence, whereas the land surface conducts heat slowly,
with the seasonal signal penetrating perhaps a meter or so. Additionally, the
specific heat capacity of liquid water is significantly higher than that of
most materials that make up land. Together, these factors mean that the heat
capacity of the layer participating in the seasonal cycle is much larger over
the oceans than over land, with the consequence that the air over the land
warms faster and reaches a higher temperature than the air over the ocean.[11]
Heating of the air over the land reduces the air's density, creating an area of
low pressure. This produces a wind blowing toward the land, bringing moist
near-surface air from over the ocean. Rainfall is caused by the moist ocean air
being lifted upwards by mountains, surface heating, convergence at the surface,
divergence aloft, or from storm-produced outflows at the surface. However the
lifting occurs, the air cools due to expansion, which in turn produces
condensation.
In winter, the land cools off quickly, but the ocean retains heat longer.
The cold air over the land creates a high pressure area which produces a breeze
from land to ocean.[11] Monsoons are similar to sea and land breezes, a term
usually referring to the localized, diurnal (daily) cycle of circulation near
coastlines, but they are much larger in scale, stronger and seasonal.[12]
----- Original Message ----- From: "Stephen Salter" <[email protected]>
To: <[email protected]>
Cc: <[email protected]>; "Andrew Lockley"
<[email protected]>; <[email protected]>; <[email protected]>;
<[email protected]>; <[email protected]>;
<[email protected]>; <[email protected]>
Sent: Saturday, May 09, 2009 6:43 AM
Subject: [geo] Re: Balancing the pros and cons of geoengineering
Hi All
The attached paper by Zickfeld et al shows, in figure 2, what might
happen to the Indian Monsoon if we do nothing. Cooling the sea relative
to the land should move things in the opposite direction.
Stephen
Emeritus Professor of Engineering Design
School of Engineering and Electronics
University of Edinburgh
Mayfield Road
Edinburgh EH9 3JL
Scotland
tel +44 131 650 5704
fax +44 131 650 5702
Mobile 07795 203 195
[email protected]
http://www.see.ed.ac.uk/~shs
Alan Robock wrote:
Dear Ken,
I agree. We need several models to do the same experiment so we can
see
how robust the ModelE results are. That is why we have proposed to the
IPCC modeling groups to all do the same experiments so we can compare
results. Nevertheless, observations after large volcanic eruptions,
including 1783 Laki and 1991 Pinatubo, show exactly the same precip
reductions as our calculations.
Even if precip in the summer monsoon region goes down, how important
is
it for food production? It will be countered by increased CO2 and
increased diffuse solar radiation, both of which should make plants
grow
more. We need people studying impacts of climate change on
agriculture
to take our scenarios and analyze them.
Alan
Alan Robock, Professor II
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:
[email protected]
New Brunswick, NJ 08901-8551 USA
http://envsci.rutgers.edu/~robock
Ken Caldeira wrote:
A few questions re claims about monsoons:
1. How well is the monsoon represented in the model's base state? Is
this a model whose predictions about the monsoon are to be trusted?
2. Since the believability of climate model results for any small
region based on one model simulation is low, for some reasonably
defined global metrics (e.g., rms error in temperature and precip,
averaged over land surface, cf. Caldeira and Wood 2008) is the
amount
of mean climate change reduced by reasonable aerosol forcing? (I
conjecture yes.)
Alan is interpreting as significant his little brown blotches in the
right side of Fig 7 in a model with 4 x 5 degree resolution (see
attachment).
How does the GISS ModelE do in the monsoon region? If you look at
Fig
9 of Jiandong et al (attached), at least in cloud radiative forcing,
GISS ModelE is one of the worst IPCC AR4 models in the monsoon
region.
So, while Alan may ultimately be proven right, it is a little
premature to be implying that we know based on Alan's simulations
how
these aerosol schemes will affect the Indian monsoon.
If you look at Caldeira and Wood (2008), we find that idealized
Arctic
solar reduction plus CO2, on average precipitation is increased
relative to the 1xCO2 world.
___________________________________________________
Ken Caldeira
Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA
[email protected] <mailto:[email protected]>; [email protected]
<mailto:[email protected]>
http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968
>
--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.
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