Balancing the pros and cons of geoengineering

[John Nissen]

 

Hi all,

 

Alan Robock has said:

 

"Whether we should use geoengineering as a temporary measure to avoid the most serious consequences of global warming requires a detailed evaluation of the benefits, costs, and dangers of different options."

 

As you may already know, I am keen for rapid development and deployment of SRM (solar radiation management) in the Arctic, with some benefits (if successful):

 

B1.  Save the Arctic sea ice and associated ecosystem.

B2.  Slow (and preferably halt) Arctic warming. 

B3.  Reduce discharge of CO2 and methane, contributing to global warming and ocean acidification.

B4.  Reduce risk of massive methane discharge, sufficient to add several degrees of global warming. 

B5.  Slow the rise in sea level from Greenland glaciers.

B6.  Reduce risk of Greenland ice sheet destabilisation, and associated 6 metres of sea level rise.

B7.  Develop the SRM techniques to use at other latitudes.

 

B4 amounts to a reduction in the risk of such catastrophic global warming that human civilisation could not survive.

 

Against this we have the concerns of those who currently benefit from a warmer Arctic:

 

C1.  Oil and mining industries, prospecting in the Arctic region.

C2.  Traders who use the North-West passage.

C3.  Greenlanders and others who may prefer a warmer climate (cf. Inuit, who are having their way of life destroyed).

 

I think we should try to counter people's natural fears about SRM geoengineering, especially stratospheric sulfur aerosols.  What are the most frequent objections?  One often reads that the remedy (geoengineering) may be worse than the disease (global warming).  We need to present a balanced picture.

 

General fears:

 

G1.  Geoengineering is interfering with nature.  (I heard that fear only this morning.)

G2.  We've made such a hash of interventions in the past, we're bound to make a hash of geoengineering.

G3.  Moral hazard - geoengineering is a licence to continue CO2 pollution.

G4.  Geoengineering is being offered as a silver bullet, which it cannot be.

G5.  You'll need international agreement - and that will be even more difficult to get than agreement on emissions reduction.

G6.  Too expensive - we always underestimate.

G7.  Too cheap, so anybody could do it.

G8.  It will not work.  (We heard at the DIUS hearing "if emissions reduction doesn't work, why should geoengineering work")

G9.  It will work - but you might overdo it by mistake, leading to an ice age.

G10.  High risk of "unknown unknowns" turning out to be disastrous side-effects.

G11.  Our understanding is too limited. To quote the "Climate Safety report":

 

".. even with the extraordinary advances in climate science to date, our understanding of it has not developed to such a point as to allow confidence that deploying direct cooling techniques would not cause more harm than good." [1]

 

 

Specific fears of stratospheric aerosols (from Robock [2]):

 

S1.  Could have adverse effect on some regional climate(s) and ecosystem(s) [4]

S2.  Doesn't help with ocean acidification.

S3.  Ozone depletion.

S4.  Effect on plants (but more diffuse light has positive benefit?)

S5.  Acid rain (noting that Alan Robock has withdrawn this particular objection)

S6.  Effect on cirrus clouds.

S7.  Disappearance of blue skies (and appearance of red sunsets?) could have negative psychological impact.

S8.  Less sun for solar power.

S9.  Environment impact of implementation (e.g. if put sulfur in jetliners fuel).

S10.  If stop, previously suppressed global warming will spring back to hit you.

S11.  Cannot stop quickly enough, if you did need to.

S12.  Human error, with means of delivery, causing dreadful accident.

S13.  Moral hazard = G3.

S14.  Cost = G6

S15.  Commercial control of technology

S16.  Military use of technology

S17.  Conflict with current treaties

S18.  Control of the thermostat

S19.  Questions of moral authority  

S20.  Unexpected consequences = G10.

 

Alan has since withdrawn objections on acid rain, S5, and cost, S14, but added a new one [3]:

 

S21.  Ruin astronomical observations

 

Do we have any more benefits, concerns, general fears or specific fears to add to these lists?

 

Cheers,

 

John

 

 

[1] http://climatesafety.org/wp-content/uploads/climatesafety.pdf

 

[2]  http://www.thebulletin.org/files/064002006_0.pdf.  Also see [3].

 

[3]  Email from Alan Robock to the geoengineering and climate intervention groups on 9th April:

 

----

 

Dear All,

As some of you know, I published a paper last year:

Robock, Alan, 2008:  20 reasons why geoengineering may be a bad idea.
Bull. Atomic Scientists, 64, No. 2, 14-18, 59, doi:10.2968/064002006.

http://climate.envsci.rutgers.edu/pdf/20Reasons.pdf

which also produced a roundtable discussion:

http://www.thebulletin.org/web-edition/roundtables/has-the-time-come-geoengineering

Since then, I have been evaluating these reasons and two of them seem to
not be of concern, excess acid deposition and cost.  Our two papers on
these results, now under review, are:

Kravitz, Ben, Alan Robock, Luke Oman, Georgiy Stenchikov, and Allison B.
Marquardt, 2009: Sulfuric acid deposition from stratospheric
geoengineering with sulfate aerosols.  Submitted to J. Geophys. Res.

http://climate.envsci.rutgers.edu/pdf/AcidDepositionJGRsubmitted.pdf

Robock, Alan, Allison B. Marquardt, Ben Kravitz, and Georgiy Stenchikov,
2009:  The practicality of geoengineering.  Submitted to Geophys. Res.
Lett.

http://climate.envsci.rutgers.edu/pdf/practicality8NoFig3.pdf

But I have also been giving talks on the subject and two days ago a
member of an audience suggested another reason why geoengineering (with
stratospheric aerosols) may be a bad idea:

It would ruin Earth-based optical astronomy!

With the tremendous investment in equipment, and mountain-top
observatories to get above most of the junk in the atmosphere, not to
mention sophisticated signal processing algorithms to remove the
remaining atmospheric influence, how could astronomers stay silent and
allow permanent clouds that would block their seeing?

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

----

 

[4] Robock et al.

 

Regional Climate Responses to Geoengineering with Tropical and Arctic SO2 Injections

 

[quote] The safety and efficacy of the recent suggestion of injection of sulfate aerosols into the Arctic stratosphere to prevent sea ice and Greenland from melting while avoiding adverse effects on the biosphere at lower latitudes [Lane et al., 2007] are not supported by our results. While Arctic temperature could be controlled, and sea ice melting could be reversed, there would still be large consequences for the summer monsoons, since the aerosols would not be confined to the polar region.

[William Fulkerson]

Dear John:

I did not see a principal advantage of SRM listed.  That is that it is reversible, at least for sulfates in the stratosphere and for cloud whitening.

Cheers,

Bill

Bill Fulkerson, Senior Fellow

Institute for a Secure and Sustainable Environment

University of Tennessee

311 Conference Center Bldg.

Knoxville, TN 37996-4138

wf...@utk.edu

865-974-9221, -1838 FAX

Home

865-988-8084; 865-680-0937 CELL 

2781 Wheat Road, Lenoir City, TN 37771

[Eugene I. Gordon]

I don't get it. The potential benefits are mostly real and possibly essential. Most of the objections are hypothetical; but certainly something to be concerned about and not ignored. However, done in careful moderation they are reversible. There is no obvious runaway effect from geoengineering.

 

I would like to see a list of objections to a small controlled experiment. I anticipate that small controlled experiments do not invoke the list G1 through

G11. If correct such experiments will help to cull or eliminate the list without danger.

---

From: geoengi...@googlegroups.com [mailto:geoengi...@googlegroups.com] On Behalf Of William Fulkerson
Sent: Wednesday, April 29, 2009 10:53 AM
To: j...@cloudworld.co.uk
Cc: geoengineering; Brian....@manchester.ac.uk
Subject: [geo] Re: Balancing the pros and cons of geoengineering

[Alan Robock]

Dear Gene,

The problem with a small controlled experiment of stratospheric
geoengineering is that you would not be able to measure either the
resulting aerosol cloud or the climate effects. In fact, nature has
done this for us. The Kasatochi volcano in Alaska erupted in August,
2008, putting 1.5 Tg SO2 into the lower stratosphere. Climate model
experiments and observations both show that the effects were too small
to detect above weather variability. The only way to test the climate
effects of stratospheric geoengineering is to actually do it full-scale.

Furthermore, we have no means to inject the SO2 if we wanted to.

Furthermore, existing observing systems for stratospheric aerosols are
difficult to use. The SAGE satellites are no longer working. There is
a spare SAGE III on the shelf at NASA, but there are no plans to launch
it. Calipso lidar can make episodic measurements along very narrow
tracks, but cannot measure the properties we want, like size
distribution.

We could start to design injection systems, such as from airplanes, and
test how well they produce small aerosol clouds, but how they would work
injecting SO2 or H2S into existing stratospheric clouds could not be
tested, except theoretically. Even if we can inject the precursor
gases, can we create particles of the desired size distribution?

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

On Wed, 29 Apr 2009, Eugene I. Gordon wrote:

> I don't get it. The potential benefits are mostly real and possibly
> essential. Most of the objections are hypothetical; but certainly something
> to be concerned about and not ignored. However, done in careful moderation
> they are reversible. There is no obvious runaway effect from geoengineering.
>
> I would like to see a list of objections to a small controlled experiment. I
> anticipate that small controlled experiments do not invoke the list G1
> through
> G11. If correct such experiments will help to cull or eliminate the list
> without danger.
>
> _____
>

> <mailto:wf...@utk.edu> wf...@utk.edu

[John Nissen]

Hi Bill,

 

I agree that the ability to halt deployment is an important advantage for stratospheric aerosol (compared to, say, space discs).  But I think S11 covers the risk of it not being removable quickly enough.  For example if there was some event, such as a large volcanic eruption, threatening to enlarge the ozone hole, then one might want to remove the sulfur aerosol quite quickly.  Ozone depletion only happens below a certain temperature, so one could apply sulfur aerosol in the spring such that most of it would fall out before the following winter.

 

Marine cloud whitening/brightening can be stopped almost instantaneously, and seems to have fewer potential side-effects than stratospheric aerosols.  However the technology probably requires a few years of development and manufacturing before it can be deployed on sufficient scale to save the Arctic ice.  We may not have that luxury of time, if the sea ice threatens to disappear even quicker than now expected, or if we want to minimise risk of consequences should it suddenly disappear.  (I regard SRM in Arctic as a supremely urgent risk reduction exercise.)

 

Cheers,

 

John

 

 

----- Original Message -----

From: William Fulkerson

To: j...@cloudworld.co.uk

Cc: geoengineering ; Brian....@manchester.ac.uk

[Stephen Salter]

Hi All

A comment about John's item G2 'that we make such a hash of everything
in the past that we are bound to make a hash of geo-engineering'.

Everyone likes to believe this but the reality is that we magnify the
hashes and ignore the many successes.

I was certainly very bad to introduce rabbits to Australia. But horses
to America? Potatoes to Europe?

Thalidomide was tragic. But antiseptics? Antibiotics? Anesthetics? Vaccines?

The Titanic sank but must most ships do not sink and do not get films
made about them not sinking.

I suggest that the success-to-hash ratio is at least a hundred to one
and we can improve it by having the time and money to do the research
properly.

Stephen

> *Regional Climate Responses to Geoengineering with Tropical and Arctic
> SO2 Injections*

>
> [quote] The safety and efficacy of the recent suggestion of injection
> of sulfate aerosols into the Arctic stratosphere to prevent sea ice
> and Greenland from melting while avoiding adverse effects on the

> biosphere at lower latitudes [/Lane et al./, 2007] are not supported

> by our results. While Arctic temperature could be controlled, and sea
> ice melting could be reversed, there would still be large consequences
> for the summer monsoons, since the aerosols would not be confined to
> the polar region.
>
> >

--
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

[jim thomas]

Bill
I don't see how you can consider SRM reversible. The modelling I've
seen (eg paper by Matthews and Caldeira) suggests that halting aerosol
injections will lead not just to a rapid jump in temperature but
indeed a jump to a higher global temperature than if geo-engineering
had not been attempted because of the weakening of carbon sinks. If
stopping is that dangerous than politically speaking this is not a
reversible technology. Once you've started it would be too dangerous
to stop

I'm talking here about aerosols specifically - I would be interested
to hear from Ken, Alan and others whether they would expect the same
dangerous jump in temperatures if a cloud whitening scheme were to
'switched off'.

Jim Thomas
ETC Group.

[Alvia Gaskill]

Shame on you. Were they white rabbits?

"I was certainly very bad to introduce rabbits to Australia. But horses
> to America?"

----- Original Message -----
From: "Stephen Salter" <S.Sa...@ed.ac.uk>
To: <j...@cloudworld.co.uk>
Cc: "geoengineering" <geoengi...@googlegroups.com>;
<Brian....@manchester.ac.uk>

[Alvia Gaskill]

The Kasotchi eruption column only went up to 35,000 ft, the Lowermost
Stratosphere, not the Lower Stratosphere, so no global or regional climatic
impact would have been expected. Concept correct, example wrong. What one
means by "full scale" has yet to be determined. A level that would produce
a measurable decrease in downwelling solar radiation might not have any
seasonally detectable climate impact even though the aerosol itself could be
measured. I would guess that 100,000 tons could be measured, 250,000 would
affect solar radiation and >500,000 would affect climate. Discrete samples
can be collected from existing high altitude aircraft so that size
distribution can be estimated. As to your continuous concern about aerosol
droplet size, I think it is important that everyone understand that there
are three scenarios being debated: droplets small enough to maximize
backscattering (about the size of the background aerosol), droplets the size
of the Pinatubo aerosol and droplets much larger than Pinatubo's. If the
latter is the general result, then it won't produce the desired effect. At
this point, we simply don't know. Unlike the volcanos, however, we have the
options of releases of precursor at different times, places and altitudes
some or all of which may enable us to tailor the droplet size, number and
distribution.


http://volcanoes.suite101.com/article.cfm/satellites_see_kasatochi_eruption

An explosive eruption occurred at Kasatochi Volcano (52.18ºN, 175.51ºW) on
the afternoon of August 7th, 2008, sending volcanic ash and gas 35,000 feet
into the atmosphere

Read more: "Satellites See Kasatochi Eruption: Volcano Erupts in Alaska's
Aleutian Island Chain August 7, 2008" -
http://volcanoes.suite101.com/article.cfm/satellites_see_kasatochi_eruption#ixzz0E5Ho14Kf&A

[Stephen Salter]

Jim Thomas

Switching on and off happens all the time already. The rate at which
the dimethyl sulphide needed to make cloud condensation nuclei is
produced by phytoplankton depends on the area of sea with the right
temperature and daylight and is turned on and off with the seasons. The
area of the clouds we are modifying depends on the variations of
atmospheric pressure. The rate at which salt aerosol is produced by
breaking waves depends on wind speed and shoots up very rapidly when it
exceeds 13 metres per second. These sources are being turned on and off
by much larger amounts than we would ever need but which we can easily
measure. We are just making a small nudge which will actually be quite
hard to detect. We are adding brakes, steering and a reverse gear to a
vehicle which at present has only an accelerator which has been jammed
hard down.

If a geoengineering solution is doing a good job why would we want to
switch it off? We might want to do so for every volcanic eruption until
the cooling system was needed again. If you have hundreds of
well-dispersed, independent sources, the probability of them all failing
simultaneously is vanishingly small.

Stephen Salter

--
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
S.Sa...@ed.ac.uk
http://www.see.ed.ac.uk/~shs

[Alan Robock]

Dear Alvia,

You can guess whatever you want, but I know of no examples of such low
stratospheric loading that had a detectable climatic effect. And I have
no idea what you mean by lowermost or lower stratosphere. The
stratosphere begins at the tropopause, which is lower in the Arctic and
higher in the tropics.

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

[Eugene I. Gordon]

You seem to be ignoring the fact that smokestack emissions and tailpipe
emissions of SO2 aerosols had a substantial cooling effect pre 1973 and were
outlawed in the US and Europe thereafter, at which time the cooling
immediately stopped and warming continued. That is documented in a NASA
paper.
I don't think there was any injection into the stratosphere.

[Alvia Gaskill]

The term "lowermost stratosphere" or LMS is commonly used as indicated in
the excerpt from this college level textbook produced by NASA and has been
popularized by TAMU professor Andrew Dessler among others as a Google search
shows. An eruption that goes above the tropical tropopause in the Arctic,
i.e. into the Overworld stratosphere (>53,000 ft), would produce aersosol
that would tend to run downwards towards the midlatitudes as was the case
with Novarupta and if large enough, affect global climate. An eruption like
Kasatochi would produce short lived aerosol that would be rapidly removed
from the LMS even though the sulfur burden was more than sufficient to alter
climate if injected into the Overworld. Since we have had this discussion
previously, it would be helpful and less time consuming on my part if you
would not deny facts simply because I am the one presenting them and/or
because they contradict your stated beliefs against geoengineering. Neither
one of those benefits anyone.

http://www.ccpo.odu.edu/SEES/ozone/class/Chap_6/6_5.htm
5.1 Mean Meridional Circulation in the Overworld and the Lowermost
Stratosphere
For time scales greater than several months, the mass flux through the
tropopause is ultimately driven by large-scale processes related to the
Brewer-Dobson circulation. To show this, it is helpful to further divide the
stratosphere into the overworld and the lowermost stratosphere. The
overworld is the region above the 380K isentropic surface. The lowermost
stratosphere is the dark shaded region between the 380K isentropic surface
and the tropopause. Figure 6.19 shows schematically these two layers of the
stratosphere and the dynamical processes that occur in each.

In Figure 6.19, the tropopause is shown by the thick line using pressure
coordinates. The tropopause is near 300 mb at the pole and 100 mb in the
tropics. Transport in the overworld is controlled by the Brewer-Dobson
circulation. That is, the strength of the upward STE in the tropics and
downward STE in the extratropics is controlled by the hemispheric
Brewer-Dobson circulation rather than by smaller scale, local transport
processes at the tropopause boundary. For material descending into the
troposphere, once it crosses from the overworld into the lowermost
stratosphere, the time scale for it to cross the tropopause is on the order
of a season. The actual transport from lowermost stratosphere into the
troposphere is governed by smaller scale extratropical processes such as
blocking anticyclones, cut-off lows and tropopause folds, discussed below.

http://atmo.tamu.edu/profile/ADessler

http://geotest.tamu.edu/userfiles/216/dessler1995.pdf (attached)

[John Gorman]

This scare ,that stratospheric areosols would result in an even more global
warming if stopped, has appeared in many articles. I therefore read the
relevent papers fairly carefully and my reading is that temeratures would
simply rise quickly to where they would have been without geoengineering.
i.e. exactly what one would expect.

There is no overshoot and no lasting effect.

These are of course the model simulations -I think one of them might have
been Ken's- but I suspect that Mount Pinatubo would give the same conclusion
.

In articles this is often coupled with the suggestion that geoengineering
has been done instead of emissions reduction but noone here is sugesting
that.

John Gorman

----- Original Message -----
From: "jim thomas" <jimtho...@gmail.com>
To: <wf...@utk.edu>
Cc: <j...@cloudworld.co.uk>; "geoengineering"
<geoengi...@googlegroups.com>; <Brian....@manchester.ac.uk>
Sent: Wednesday, April 29, 2009 5:10 PM
Subject: [geo] Re: Balancing the pros and cons of geoengineering

[John Nissen]

Dear Professor Hansen,

Congratulations on your noble efforts to persuade our UK government to adopt
CCS, which have now borne fruit [1]. However, if it becomes generally
recognised that drastic global emissions reduction, even with CCS, would be
insufficient to halt Arctic warming and sea ice retreat (in turn threatening
massive methane release and Greenland ice sheet disintegration), then there
may be panic measures taken with geoengineering. The geoengineering is
likely to involve stratospheric sulphate aerosols [2]. But measures taken
in panic can be dangerous. There has been insufficient experimentation with
the aerosols, and, according to Alan Robock (see email below), the aerosol
effect is difficult to observe except with full-scale deployment. In
particular he is concerned that none of the SAGE satellites, used to measure
aerosols from volcanoes in the past, may be currently available.

Would it be possible for NASA to help in aerosol experimentation, or at
least in setting up aerosol observation systems, as a matter of urgency?

Note that there has been no public funding for research into geoengineering
in the UK or US [3]. However I gather Mr Holdren considers that
geoengineering should not be ruled out [4], so you might have a better
chance in the US.

Kind regards,

John Nissen,
Chiswick, London W4

[1]
http://www.businessgreen.com/business-green/news/2240988/coal-without-ccs-uk-miliband
[2]
http://rsta.royalsocietypublishing.org/content/366/1882/4007.short?rss=1&ssource=mfc
[3]
http://www.imeche.org/NR/rdonlyres/5EEE7C72-4439-4E6D-B6DB-17DBE06C4264/0/GeoEngineeringIMechEPolicy.pdf
[4]
http://www.guardian.co.uk/environment/2009/apr/08/geo-engineering-john-holdren

----- Original Message -----
From: "Alan Robock" <rob...@envsci.rutgers.edu>
To: "Eugene I. Gordon" <eugg...@comcast.net>
Cc: <wf...@utk.edu>; <j...@cloudworld.co.uk>; "'geoengineering'"
<geoengi...@googlegroups.com>; <Brian....@manchester.ac.uk>

[John Nissen]

Hi all,

Trying to track down Prof Hansen, I accidentally discovered that he is
speaking at a conference tomorrow. Is anybody going to the conference, or
do you know anybody? I'd like to check he's received my email, and is going
to reply!

Will Prof Hansen mention geoengineering (namely carbon stock management) as
a "top strategy" for reducing atmospheric carbon dioxide? Will he mention
what reducing carbon dioxide will NOT do - such as saving Arctic sea ice,
for which we need a different kind of geoengineering (namely solar radiation
management)?

Re conference details, this is from "The Switch" - ANPED's newsletter:

----
Upcoming Events - May 2009

2 May 2009, Columbia University, New York City, United States

350 Climate Conference. This event will bring together significant figures
from within the climate debate including keynote speaker Dr. James Hansen,
Director of NASA's Goddard Institute for Space Studies. The conference will
critically examine the question of "What is the safe upper limit of
atmospheric carbon dioxide?" as well as explore the top strategies for
reducing atmospheric carbon dioxide.

http://www.350conference.org

----

Cheers from Chiswick,

John

[snip]

[John Nissen]

 

Hi all,

 

I'm restricting this analysis to geoengineering with stratospheric aerosols to save the Arctic sea ice.  I've not received any additions to the list of pros and cons I posted on 29th April.

 

Some points have been discussed, mostly on 29th April also:

 

S11.  Cannot stop quickly

William Fulkerson said that the stratospheric aerosol technique is effectively "reversible".  I discussed this point, suggesting the technique might be employed in spring, such that most aerosol would be gone by the following winter.

 

G2.  Making a hash of things

Stephen Salter argued that we don't often make a complete hash of things - it's just that hashes are more newsworthy than successes.  Good research is a safeguard.

 

G1-G11 General objections to geoengineering

Eugene Gordon suggested small-scale experiments would not fall foul of any of these general objections.  However, Alan Robock pointed out the difficulty of carrying out such experiments to get measurable results, without going full-scale.  Alvia Gaskill begged to differ, and there was a discussion of layers in the stratosphere.  I wrote to Prof Hansen asking for NASA help for experimentation (but no reply received).

 

S10  If stop deployment, global warming will spring back

Jim Thomas is worried by the effect of stopping deployment, leading to rapid warming.  John Gorman said that the temperature would only rise to what you would have had without the geoengineering - there would be no overshoot and no lasting effect.  (I don't think it would even rise that much. It would simply rise as fast as forced by the current CO2e level above pre-industrial, other things being equal. Of course the CO2e level may have gone up considerably while the geoengineering was being applied, so there will be a jump in the RATE of temperature increase, as you'd expect, but no inertial or coiled-spring effect.  Is that right, Ken?)

 

G3  The moral hazard

This has been dismissed - as being the same argument used against adaptation!  The Greenpeace position on this [1] was heavily criticised in the DIUS report [2].

 

I suggest that the moral hazard has to be discounted in balancing the risks, as it is impossible to quantify.  Likewise all the other general fears in G1-11.

 

For the time being I suggest we ignore the concerns of people who benefit from a warmer Arctic: CI-C3.

 

Thus we should concentrate on B1-B7 and S1-S21.

 

The benefits can be costed in terms of what happens if the sea ice disappears.  Against this are the risks of undesirable effects of the geoengineering - the downsides.  For obtaining a balance of risks, we need to:

 

* calculate probability of success to halt Arctic warming and sea ice retreat;

* estimate each benefit - as a cost of NOT doing the geoengineering (e.g. losing an ecosystem);

* for each of these costs, multiply by probability of it happening if the sea ice disappears;

* sum the above risks to be averted;

* multiply by the probability of success to obtain overall benefit;

* calculate probability of each downside;

* estimate the cost of each downside;

* multiply probability and cost to obtain risk from doing the geoengineering;

* sum the downside risks to obtain total downside risk;

* compare the overall benefit with the total downside risk.

 

Is that a fair approach? 

 

As a refinement, we can vary the risk of geoengineering according to when we start deployment - which will vary according to when the Arctic sea ice first disappears.  So we add the time dimension.

 

Cheers,

 

John

 

 

[1]  See David Santillo answer to Q39:

 http://www.publications.parliament.uk/pa/cm200708/cmselect/cmdius/uc1064-i/uc106402.htm

 

[2] DIUS report - geoengineering section:

http://www.publications.parliament.uk/pa/cm200708/cmselect/cmdius/uc1064-i/uc106402.htm

 

 

----- Original Message -----

From: John Nissen

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

----

 

[John Nissen]

Hi again,

 

I am getting a lot of support for concentrating on using stratospheric aerosols to save the Arctic sea ice, as a most urgent application for geoengineering.

 

To me, perhaps the biggest specific danger is Alan Robock's first, so I'd like to start the discussion on this:

 

S1.  Could have adverse effect on some regional climate(s) and ecosystem(s) [4]

 

where [4] is from Robock et al.

----

Regional Climate Responses to Geoengineering with Tropical and Arctic SO2 Injections

 

[quote] The safety and efficacy of the recent suggestion of injection of sulfate aerosols into the Arctic stratosphere to prevent sea ice and Greenland from melting while avoiding adverse effects on the biosphere at lower latitudes [Lane et al., 2007] are not supported by our results. While Arctic temperature could be controlled, and sea ice melting could be reversed, there would still be large consequences for the summer monsoons, since the aerosols would not be confined to the polar region.

----

 

Alan claims that the aerosols would not be confined to the polar region.  But doesn't this depend on: the timing range of the release of precursor, the height range in the stratosphere, and the latitude range?  Suppose that the release is in spring such that most of the aerosol has gone by the winter?  Has any modelling been done on this and other various possibilities?

 

Cheers,

 

John

 

[xben...@aol.com]

John:

You strike the nub of it:

"Alan claims that the aerosols would not be confined to the polar
region. But doesn't this depend on: the timing range of the release of
precursor, the height range in the stratosphere, and the latitude
range? Suppose that the release is in spring such that most of the
aerosol has gone by the winter? Has any modelling been done on this
and other various possibilities?"

This is what simulations are for, at first, but experiments must
follow.

Also, what's the magnitude of the monsoon change, and its
uncertainties? Further, as I pointed out to Alan, the monsoon is not a
totally positive phenomenon -- there's flooding, crop damage, and loss
of life. I've been through some and they are indeed damaging. Soall
this needs to be studied in detail BEFORE we confront the truly hard
issue: how to trade off lesser rainfall against the Arctic dangers.

Gregory Benford

-----Original Message-----
From: John Nissen <j...@cloudworld.co.uk>

=2
0 To: geoengineering

=2
0 contributing to global warming and ocean acidification.

point as to allow20confidence that deploying direct cooling

20 treaties

[Andrew Lockley]

It's essential to consider the 'unmodified case'.  Whatever 'damage' geoeng does has to be weighed against the damage that would occur from unfettered global warming to the Arctic region.  The plight of the Polar bear is the poster child for global warming, which makes my point in a very clear way.

A

2009/5/8 <xben...@aol.com>

[Ken Caldeira]

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

kcal...@ciw.edu; kcal...@stanford.edu
http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968  

[Alan Robock]

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

> kcal...@ciw.edu <mailto:kcal...@ciw.edu>; kcal...@stanford.edu
> <mailto:kcal...@stanford.edu>

[Stephen Salter]

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
S.Sa...@ed.ac.uk
http://www.see.ed.ac.uk/~shs

--

[Alan Robock]

Dear Stephen,

I would not put much faith in this highly idealized model, unless it
could be shown to actually simulate past monsoon variations. It is a
nice intellectual exercise, but ignores many of the important processes
of the climate system.

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

[Alvia Gaskill]

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" <S.Sa...@ed.ac.uk>
To: <rob...@envsci.rutgers.edu>
Cc: <kcal...@dge.stanford.edu>; "Andrew Lockley"
<andrew....@gmail.com>; <XBen...@aol.com>; <j...@cloudworld.co.uk>;
<geoengi...@googlegroups.com>; <Brian....@manchester.ac.uk>;
<sam.c...@gmail.com>; <pw...@cam.ac.uk>
Sent: Saturday, May 09, 2009 6:43 AM
Subject: [geo] Re: Balancing the pros and cons of geoengineering

[Eugene I. Gordon]

Good discussion. This is what geoengineering is all about.

[John Nissen]

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

[Andrew Lockley]

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 <j...@cloudworld.co.uk>

[Alvia Gaskill]

This depends on the objective.  For a global aerosol program designed to stop the warming of the entire planet, the answer is no.  In this case, we want the aerosol to stay suspended as long as possible to get the maximum amount of sunlight scattering and to minimize the quantity of precursor that has to be transported to the stratosphere.  The longer lived aerosol would also tend to be less of a problem in ozone depletion as the surface area would be reduced relative to larger shorter lived droplets. 

 

If the aerosol precursor is released in the tropical stratosphere, it will circle and cover the entire globe, including India.  Releases outside the tropics could be attempted, but this would create uneven warming of a different kind and a good portion of India and all of China is outside the tropics anyway.

 

In the case of an Arctic only aerosol program, the aerosol size issue is probably the same, but the supporters have set as criteria releasing the precursor in the upper troposphere (around 45,000 ft) in the spring with the goal of having it all gone by the end of the summer.  This would minimize any ozone depletion as the aerosol would have to be present in the winter for the "dark" reactions to take place.  Having the aerosol active only during the summer might lessen or have no impact on monsoons or other seasonal rainfall patterns.  There is no data to support this one way or the other.

 

Note also that the limited modeling done to date in addition to the resolution of regional impacts issue mentioned earlier today also has focussed almost entirely on high loading of aerosol precursor to simulate that required to offset a doubling of CO2 from pre-industrial.  While these extreme conditions may actually be required at some point decades from now, a more likely scenario is one of a gradual incremental increase in the aerosol to match GHG forcing or to offset loss of tropospheric aerosols.  In such cases, the climate system may adjust and there may be no impact on monsoonal flows or precipitation or the effect may be very gradual and so can be dealt with by adaptation.  The point is we simply don't know because these studies haven't been done.  Thus the risk questions posed by John Nissen represent work that needs to be done.

[Andrew Lockley]

A few comments on that:

1) Droplet size shouldn't affect chemistry.  Both surface area and the cross sectional area are proportional to the square of the radius.  Volume affects residence time, and is proportional to the cube of the radius.  Big droplets are shorter-lived, and hence more controllable, but less mass-efficient.

2) The Brewer Dobson circulation drives aerosol transport and predominantly acts towards the poles.  I am not aware of East-West winds in the stratosphere (but that's probably because I know sweet FA about such things, not cos they don't exist)  In the absence of EW circulation, what will force aerosols to India?
3) Release into the high stratosphere would remove the need to release precursor at the equator, as lifting from the BDC would not be needed.  What's the peak height of the balloons?

4) On a more general point, should we start a 'wish list' of research papers that need to be done.  Eager young PhD students will hopefully come along and pick these up for us. Or is that just fantasy?

A

2009/5/10 Alvia Gaskill <agas...@nc.rr.com>

[dsw_s]

Droplet size may affect chemistry because of surface tension. At
sufficiently small scales, a high-curvature surface isn't the same
chemically as a lower-curvature surface.

My impression is that the Brewer Dobson circulation is the net
circulation after east-west wind is canceled out, since the zonal
circulation goes in circles of fairly homogeneous air and thus doesn't
contribute to net long-term transport. But I don't actually know any
more about it than you do.

On May 9, 9:11 pm, Andrew Lockley <andrew.lock...@gmail.com> wrote:
> A few comments on that:1) Droplet size shouldn't affect chemistry.  Both
> surface area and the cross sectional area are proportional to the square of
> the radius.  Volume affects residence time, and is proportional to the cube
> of the radius.  Big droplets are shorter-lived, and hence more controllable,
> but less mass-efficient.
> 2) The Brewer Dobson circulation drives aerosol transport and predominantly
> acts towards the poles.  I am not aware of East-West winds in the
> stratosphere (but that's probably because I know sweet FA about such things,
> not cos they don't exist)  In the absence of EW circulation, what will force
> aerosols to India?
> 3) Release into the high stratosphere would remove the need to release
> precursor at the equator, as lifting from the BDC would not be needed.
>  What's the peak height of the balloons?
> 4) On a more general point, should we start a 'wish list' of research papers
> that need to be done.  Eager young PhD students will hopefully come along
> and pick these up for us. Or is that just fantasy?
>
> A
>

> 2009/5/10 Alvia Gaskill <agask...@nc.rr.com>

> > *From:* Andrew Lockley <andrew.lock...@gmail.com>
> > *To:* John Nissen <j...@cloudworld.co.uk>
> > *Cc:* Alvia Gaskill <agask...@nc.rr.com> ; s.sal...@ed.ac.uk ;
> > rob...@envsci.rutgers.edu ; kcalde...@dge.stanford.edu ; XBenf...@aol.com;
> > geoengi...@googlegroups.com ; Brian.Laun...@manchester.ac.uk ;
> > sam.car...@gmail.com ; p...@cam.ac.uk
> > *Sent:* Saturday, May 09, 2009 8:01 PM
> > *Subject:* Re: [geo] Re: Balancing the pros and cons of geoengineering

> >> ----- Original Message ----- From: "Alvia Gaskill" <agask...@nc.rr.com>
> >> To: <s.sal...@ed.ac.uk>; <rob...@envsci.rutgers.edu>
> >> Cc: <kcalde...@dge.stanford.edu>; "Andrew Lockley" <
> >> andrew.lock...@gmail.com>; <XBenf...@aol.com>; <j...@cloudworld.co.uk>; <
> >> geoengi...@googlegroups.com>; <Brian.Laun...@manchester.ac.uk>; <
> >> sam.car...@gmail.com>; <p...@cam.ac.uk>

> ...
>
> read more »

[Peter Read]

It seems that in all innocence we kept the planet's climate roughly stable
for 8000 years [according to Ruddiman] by burning down forests, occasionally
visited by plagues [sent by Gaia if we were going ahead too fast?]. But
with the enlightenment came knowledge, of which eating the fruit has led to
the passing of much wind, resulting in too much CO2 in the atmosphere. It
does not seem there is any going back, so we need to keep on thinking how to
get ourselves out of this fine mess [as Laurel would have said to Hardy, if
not the other way round -- can never remember which was which].

A thought that has been bubbling in my head since reading the Zickfeld paper
(thankyou Stephen) and maybe obvious to everyone else, is that, supposing we
succeed in cooling the earth over the next few decades by lowering CO2
levels, through growing a lot of trees, extensive use of biochar, and
combining bioenergy with CCS, then the terrestrial earth will be cooled
faster than the oceanic earth and monsoon-like phenomena (watering the
Amazon basin, and -- on a good year -- the Sahel, besides South Asia and
East Africa) be inhibited worldwide. Thus we need to cool the ocean suface
layers as well as the land. Stephen's ships are the one obvious utterly
benign technology that has been proposed [if it works - surely time is ripe
to try it out] but also Ocean Thermal power generation and Lovelock and
Rapley's ocean pipes (with both the latter needing some cautions regarding
possible ecological effects of bringing deep ocean creepy crawllies and
suchlike to the surface).

The beauty of the ocean surface cooling technologies is that they can be
regionalised - e.g. to keep the monsoons going, to cool the coral reefs, to
chill the Gulf Stream and hopefully preserve Arctic sea ice, while allowing
North Pacific coasts, Patagonia, Tasmania and New Zealand to bask in warmer
waters. No good for the WAIS of course, so maybe a bit of Crutzen's sulphur
aerosols South of 60 deg.

It may seem that some combination of reionalized albedo modification and
carbon stock management is needed to get us out of this fine mess, meeting
Harvard economist Martin Weitzman's call for "some semblance of a game plan
for dealing realistically with what may be coming down the road".

Of course with regionalisation comes politics. Maybe people around the
North Atlantic seaboard would not take kindly to a chillier climate.
Hmmm.....

Cheers
Peter

[Alvia Gaskill]

Winds in the stratosphere (above 53,000 ft) tend to blow from east to west, but periodically reverse.  The links below are to simulations of how the Pinatubo eruption gases spread.  Release above 90,000 ft is of little value in that the gas will simply settle back down to that altitude due to the density of the air and as noted before, release outside the tropics shortens the lifetime of the aerosol, although in a more complex distribution scheme than the simple ones studied to date, it might offer some as yet unknown advantages.   Note the misuse of the word elevation for altitude.

 

http://www.gsfc.nasa.gov:80/gsfc/newsroom/tv%20page/G02-016_earth.htm (Click on "Volcanic Plume Movie" at bottom of page to see video.)

 

ITEM (2): Volcanic Plume Spreads - This computer model shows the dispersion of the volcanic plume from the Mt. Pinatubo volcano. The 1991 Pinatubo eruption was sulfur-rich, producing volcanic clouds that lasted a number of years in the stratosphere. The Pinatubo eruption widely expanded the area of ozone loss over the Arctic and Antarctic. Red colors indicate higher elevations and blue colors indicate lower elevations for the plume.

 

http://svs.gsfc.nasa.gov/vis/a000000/a000000/a000074/

 

Another animation of the Pinatubo aerosol spread generated from satellite imagery.  Appears to cover period of about 3 months post eruption.

[John Nissen]

I've been trying to find out the extent of the "disaster" of monsoon failure from Pinatubo but drawn a blank.  What does seem to cause less precipitation is an El Niño.  If we were to find that our polar aerosols were spreading towards subtropics AND there was a particularly strong El Niño, then we might decide to halt their deployment.

 

On the whole, global warming has caused increased precipitation over land, as land has warmed faster than sea, so there is more updraft to suck up the moist air from the sea.  Thus any stratospheric aerosol cooling effect is generally going to be in the direction of restoring status quo - towards the 8000 years stable level, that Peter Read was emailing about, earlier today.

 

But I'm not sure that there is going to be much spread of aerosol out of the polar region, if we get the timing and altitude right, so that aerosol acts in spring and summer but is mostly gone by winter.  We want it to mostly go by winter to avoid ozone depletion, but this should also have the effect of reducing drift.  And most of the stratospheric wind is latitudinal (West-East) near the poles, with only a small longitudinal component (mainly towards the pole).  Furthermore, at the poles the stratospheric air tends to sink - so the aerosol would tend to drop into the troposphere and get washed out before it could reach the subtropics.

 

However, suppose everything goes as wrong as it can (a small probability), how many lives might be lost through weak monsoons for a few years?  What would the lasting effect be on India's GDP?  These figures are what we have to balance against the pros of geoengineering, taking into account this small probability.

[xben...@aol.com]

All:

These comments about aerosol movement from an Arctic event are right.
Indeed, this issue of maybe affecting the monsoon is another SIDE
ASPECT to consider in experiments. The Arctic strategy assumes there
will be maybe a dozen parameters we can tune for a range of effects.

Rather than the oft bespoke worry over such a complicated system, it's
reassuring that we have so many ways to adjust the aerosols, and so
manage the Arctic. It will be the event that shows in detail what
issues will occur on the global cooling strategies that are going to
follow. A successful Arctic management will be the anti-geoengineering
groups' nightmare.

My experience of them is that they fear the Arctic agenda will work,
not that it won't.

Gregory Benford

-----Original Message-----
From: John Nissen <j...@cloudworld.co.uk>

To: Alvia Gaskill <agas...@nc.rr.com>; Andrew Lockley
<andrew....@gmail.com>
Cc: s.sa...@ed.ac.uk; rob...@envsci.rutgers.edu;
kcal...@dge.stanford.edu; XBen...@aol.com;
geoengi...@googlegroups.com; Brian....@manchester.ac.uk;
sam.c...@gmail.com; pw...@cam.ac.uk
Sent: Sun, 10 May 2009 4:21 pm
Subject: Re: [geo] Re: Balancing the pros and cons of geoengineering

I've been trying to find out the extent of the
"disaster" of monsoon failure from Pinatubo but drawn a blank.  What
does
seem to cause less precipitation is an El Niño. 
If we were to find that our polar aerosols were spreading towards

subtropics20AND

=2
0 radius.  Big droplets are shorter-lived, and hence more

controllable,
but less mass-efficient.
2) The Brewer Dobson circulation drives aerosol transport and
predominantly acts towards the poles.  I am not aware of East-West
winds in the stratosphere (but that's probably because I know sweet
FA about
such things, not cos they don't exist)  In the absence of EW
circulation, what will force aerosols to India?
3) Release into the high
stratosphere would remove the need to release precursor at the
equator, as
lifting from the BDC would not be needed.  What's the peak height
of
the balloons?
4) On a more general point, should we start a 'wish list' of
research
papers that need to be done.  Eager young PhD students will
hopefully
come along and pick these up for us. Or is that just fantasy?


A

2009/5/10 Alvia Gaskill &lt;agas...@nc.rr.com&gt;

2009/5/9 John Nissen &lt;j...@cloudworld.co.uk&gt;

&lt;agas...@nc.rr.com&gt;
To: &lt;s.sa...@ed.ac.uk&gt;; &lt;rob...@envsci.rutgers.edu&gt;

Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;
&lt;j...@cloudworld.co.uk&gt;;
&lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

=2
0 be applied to other locations such as the Amazon, Eastern

&lt;S.Sa...@ed.ac.uk&gt;
To: &lt;rob...@envsci.rutgers.edu&gt;
Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;
&lt;j...@cloudworld.co.uk&gt;; &lt;geoen
gine...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

kcal...@ciw.edu &lt;mailto:kcal...@ciw.edu&gt;;
kcal...@stanford.edu
&lt;mailto:kcal...@stanford.edu&gt;

http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1
650 704 7212; fax: +1 650 462
5968

&gt;

[Andrew Lockley]

I think that the 'anti-geoeng' movement doesn't really fear that Arctic geoeng will work.  What I think they fear is that if it works, the world will simply not bother cutting emissions.

Whilst I'm 'on the phone', I feel I need to summarise for myself the current state of play.  Please could someone correct this if it's wrong.

1) Marine could brightening looks really promising, but we have no idea if it will actually work because no-one will fund it

2) Stratospheric sulphur aerosols look fairly promising, and we can cheaply deploy them with balloons.  They might wreck the hydrological cycle in general, and the monsoon in particular. Other aerosols are worth a look.

3) Carbon dioxide air capture looks very promising, but it requires further development, and will take ages to work.

4) Biochar, ocean fertilization and various other schemes are worth a look, but will not be able to turn things around in isolation.

5) Space mirrors are a bit daft, but ones made of crisp packet (potato chip) that rotate might be less daft than other designs.

Is this fair comment?

A

2009/5/11 <xben...@aol.com>

[John Nissen]

 

Hi Andrew,

 

The "moral hazard" (geoengineering is licence to emit more CO2) is one thing - but that argument can be demolished as being the same argument that was put against adaptation - see DIUS report.  I don't think people realise that we cannot wait for emission cuts to work - and nobody's told them that they won't work by themselves, so geoengineering has to be done sooner or later.  And they think of suphate aerosols as nasty pollution.  And they don't like the idea of interfering with nature.  And they don't trust anybody who proposes technical fixes.  So it's a mish-mash of emotions against geoengineering.

 

I'm concentrating on stratospheric aerosols for the Arctic, because the Arctic needs SRM to cool it, and the marine cloud brightening isn't sufficiently developed.  The latter has big advantages of no ozone risk and it can be used on specific parts of the ocean - so it can be well targetted.  It urgently needs funding.

 

As Gregory said, it is looking as if stratospheric aerosols can be made to work effectively.  I'm waiting for discussion on the risk calculation of regional effects (S1), and then we can look at the other specific fears now: S2-S21.

[Peter Read]

Eugene
good idea
I think Biosphere Carbon Stock Management is a game plan but for reasons
stated previously think it needs to be associated with an ocean surface
cooling programme.**
Any more ideas or modifications needed?
I'm 73 and not very well
Why don't you do it?
Peter
**And a lot of modelling to capture the dynamics of an unwinding process and
avoid pitfalls such as starving the rural communities of India. But lack of
full scientific certainty should not be used as reason for delay: the game
plan will be ongoing work in progress and adjustments can be made as the
science gets better

----- Original Message -----
From: "Eugene I. Gordon" <eugg...@comcast.net>
To: <pre...@attglobal.net>
Sent: Monday, May 11, 2009 12:56 AM
Subject: RE: [geo] Re: Balancing the pros and cons of geoengineering -
eating of the fruit of the tree of knowledge


> How does one produce a game plan that ayone would pay attention to? So far
> it seems this group talks to itself and no one else listens or cares and
> in
> fact may be interested in suppressing the idea. Maybe it is time to plan a
> major meeting, get a lot of publicity, invite major players, the press,
> and
> have a session devoted to game plan. It takes money to have a meeting,
> have
> some invited speakers, and get publicity.
>
> So:
>
> Get agreement on a meeting, site and date.
> Raise some money.
> Stop talking and do something.
>
> -gene

>
> -----Original Message-----
> From: geoengi...@googlegroups.com
> [mailto:geoengi...@googlegroups.com] On Behalf Of Peter Read
> Sent: Sunday, May 10, 2009 8:17 AM
> To: j...@cloudworld.co.uk; Alvia Gaskill; s.sa...@ed.ac.uk;
> rob...@envsci.rutgers.edu

> Cc: kcal...@dge.stanford.edu; Andrew Lockley; XBen...@aol.com;
> geoengi...@googlegroups.com; Brian....@manchester.ac.uk;
> sam.c...@gmail.com; pw...@cam.ac.uk

> Subject: [geo] Re: Balancing the pros and cons of geoengineering - eating
> of
> the fruit of the tree of knowledge

> ----- Original Message -----
> From: "John Nissen" <j...@cloudworld.co.uk>

> To: "Alvia Gaskill" <agas...@nc.rr.com>; <s.sa...@ed.ac.uk>;
> <rob...@envsci.rutgers.edu>
> Cc: <kcal...@dge.stanford.edu>; "Andrew Lockley"

> <andrew....@gmail.com>; <XBen...@aol.com>;
> <geoengi...@googlegroups.com>; <Brian....@manchester.ac.uk>;
> <sam.c...@gmail.com>; <pw...@cam.ac.uk>
> Sent: Sunday, May 10, 2009 10:37 AM
> Subject: [geo] Re: Balancing the pros and cons of geoengineering
>
>
>>

>> From: "Alvia Gaskill" <agas...@nc.rr.com>
>> To: <s.sa...@ed.ac.uk>; <rob...@envsci.rutgers.edu>
>> Cc: <kcal...@dge.stanford.edu>; "Andrew Lockley"
>> <andrew....@gmail.com>; <XBen...@aol.com>; <j...@cloudworld.co.uk>;

>>> ammonium sulfate. This idea as well as Stephen's could be applied to

>>> From: "Stephen Salter" <S.Sa...@ed.ac.uk>
>>> To: <rob...@envsci.rutgers.edu>
>>> Cc: <kcal...@dge.stanford.edu>; "Andrew Lockley"
>>> <andrew....@gmail.com>; <XBen...@aol.com>;

>>>>>> kcal...@ciw.edu <mailto:kcal...@ciw.edu>;
>>>>>> kcal...@stanford.edu <mailto:kcal...@stanford.edu>

>>>>>> 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.
>>>>
>>>>
>>>> >>
>>>>
>>>
>>>
>>
>>
>> >
>
>
> >

--------------------------------------------------------------------------------



No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 8.0.238 / Virus Database: 270.12.24/2107 - Release Date: 05/10/09
07:02:00

[xben...@aol.com]

Comments:

>>2) Stratospheric sulphur aerosols look fairly promising, and we can
cheaply deploy them with balloons. They might wreck the hydrological
cycle in general, and the monsoon in particular. Other aerosols are
worth a look.

Balloons are not optimal. Airplanes work fine at Arctic needed
altitudes, < 50,000 feet. I don't think anyone really believes "They
might wreck the hydrological cycle" -- these are ~5% effects at best,
especially doubtful in the Arctic case.

>>3) Carbon dioxide air capture looks very promising, but it requires
further development, and will take ages to work.

Nope. The CROPS method (Metzger & Strand & me) can start right away and
works every year to capture at least 10% of world C emissions.

Gregory

[Hawkins, Dave]

Greg,
I don't think the us-them dichotomy is helpful. As in all areas of controversy there is a spectrum ranging from those who indiscriminately deploy whatever argument crosses their radar screen if it fits their pre-conceived idea of the "right" answer to those who actually would like to see a more rigorous description of how to design field experiments that both have trivial risks and are capable of providing useful information to better characterize the risks of full scale projects. Ignoring the former is fine but someone needs to take on the task of producing something aimed at the latter.
David

[David Schnare]

David's message is essentially correct, and in line with many other comments that have been made on this list.  Experimentation needs to accomplish multiple tasks, including documenting the efficacy of the particular approach as well as the expected and unintended outcomes that may have either positive or negative implications.

 

What David did not mention is that any organization deeply involved in climate change issues needs to either (1) admit that carbon emissions reductions, alone, will not be sufficient to prevent catastrophic climate impacts far worse than currently well considered approaches to geoengineering; or (2) admit that those who indiscriminately deploy whatever argument crosses their radar screen is not meaningfully different from those who know about geoengineering and refuse to take any public position whatever. 

David S.

--
David W. Schnare
Center for Environmental Stewardship

[xben...@aol.com]

Dave:

Of course us/them is there--we have plenty of ferocious opponents--and
without funding, we won't get to do the " rigorous description of how

to design field experiments that both have trivial risks and are
capable of providing useful information to better characterize the
risks of full scale projects."

The political logjam won;t care about our internal discussions. But
it's useful to see what the real issues are.

Believe me, there is a large block that will hate these ideas. They
can't be talked around. I've tried for 25 years.

I experienced this kind of opposition to the obvious at NASA, which I
was on the "kitchen cabinet" of Dan Goldin -- and the inertia won. Look
where they are now.


Gregory

ar...@gmail.com; pw...@cam.ac.uk

Subject: [geo] Re: Balancing the pros and cons of geoengineering


All:

These comments about aerosol movement from an Arctic event are right.
Indeed, this issue of maybe affecting the monsoon is another SIDE
ASPECT to consider in experiments. The Arctic strategy assumes there
will be maybe a dozen parameters we can tune for a range of effects.


Rather than the oft bespoke worry over such a complicated system, it's
reassuring that we have so many ways to adjust the aerosols, and so
manage the Arctic. It will be the event that shows in detail what
issues will occur on the global cooling strategies that are going to
follow. A successful Arctic management will be the anti-geoengineering
groups' nightmare.


My experience of them is that they fear the Arctic agenda will work,
not that it won't.

Gregory Benford

-----Original Message-----

From: John Nissen &lt;j...@cloudworld.co.uk&gt;

To: Alvia Gaskill &lt;agas...@nc.rr.com&gt;; Andrew Lockley
&lt;andrew....@gmail.com&gt;

    C2 answer is no.  In this case, we want the aerosol to stay

0           temperature compared to that of nearby oceans. This

            wind blowing toward the land,20bringing moist near-surface

            &lt;andrew....@gmail.com&gt;; &lt;XBenford@aol.
com&gt;;

I agree.  We need20several models to do the same

0D

 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  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

     20           trusted?

The University=2
0of Edinburgh is a charitable

[Hawkins, Dave]

Achieving GHG reductions on the required scale is a huge policy and technical challenge.  While David would like me and NRDC to accept his view that it is impossible to succeed, the fact is we disagree.  However, this dispute is quite irrelevant to the topic at hand, which is how the "geoengineering community" will go about demonstrating to policymakers that it is possible to develop a coherent program of field experiments for geoengineering that is both "safe" and produces useful information.

---

From: geoengi...@googlegroups.com [mailto:geoengi...@googlegroups.com] On Behalf Of David Schnare
Sent: Sunday, May 10, 2009 10:54 PM
To: geoengi...@googlegroups.com

[John Gorman]

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

[Bonnelle Denis]

Dear all,

 

(please forgive me if the following geometrical arguments have already been discussed).

 

The positive feedback (albedo, methane, etc.) rationale for focusing about the Arctic is doubtlessly great. But the geometry is not very favorable, especially if very tangential sun rays are concerned, which is more often the case near the poles than near the equator.

 

The most dramatic case is the one of the most tangential rays which: 1 - without geoengineering - would have traveled horizontally through the stratosphere, unharmed, and which: 2 - would be diffracted by the silica, half upwards but also half downwards, giving their heat to the earth. Seen from the sun, the relevant cross-section is around 10 or 20 km (the considered stratospheric layer's thickness) multiplied by 2000 or 3000 km (the considered bow length). Such a result (several 10,000 km²) is not negligible when compared to the whole target cross-section (the same 2000 or 3000 km, multiplied by 300 or 400 km which is the width, seen from the sun, of the true useful target region). In addition, the effect in our x0,000 km² region will be more intense, as the rays which travel quite horizontally through the stratosphere will meet much more silica than those which make a larger angle with the horizontal.

 

And even in the latter case (i.e., in all the target region, but mainly for sun rays which will reach the atmosphere with a quite small angle with the horizontal), an effect of the silica will be to increase the proportion of such rays which will be redirected towards the ground in a rather vertical direction, instead of coming quite tangentially (the blue sky will be brighter). Thus, various effects will have to be considered: lesser absorption in various layers of the atmosphere, lesser reflexion on the ocean surface, deeper penetration into the ocean, etc. It doesn't seem clear to me, whether such undesired effects will be lower than the desired fact that half of such diffracted rays will be redirected upwards, i.e. outwards of the earth climatic machine.

 

Best regards,

 

Denis Bonnelle.

Denis.B...@normalesup.org

 

 

De : geoengi...@googlegroups.com [mailto:geoengi...@googlegroups.com] De la part de John Gorman
Envoyé : lundi 11 mai 2009 09:45
À : andrew....@gmail.com; John Nissen; geoengi...@googlegroups.com
Objet : [geo] Re: Balancing the pros and cons of geoengineering

<BR

[John Gorman]

I have to admit I hadnt thought of that aspect of aerosols in the arctic.

 

To Gregory Benfold -What do you think ?

 

John Gorman

[Andrew Lockley]

Doesn't anyone have a computer simulation of light passing through various aerosols, and the scattering that results?  It would be great to be able to show doctored photos of 'geoengineered sky' vs. 'normal sky'.  Robock pointed out these effects, but it seems that the analysis has possibly been limited/flawed.

A

2009/5/11 John Gorman <gor...@waitrose.com>

[Stephen Salter]

Andrew

There is a list of packages at

http://atol.ucsd.edu/scatlib/scatterlib.htm

You can download a wonderful free computing package for liquid drops
written by Philip Laven from

http://www.philiplaven.com/mieplot.htm

See also:

http://www.philiplaven.com/index1.html

http://www.philiplaven.com/Publications.html

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
S.Sa...@ed.ac.uk
http://www.see.ed.ac.uk/~shs

Andrew Lockley wrote:
> Doesn't anyone have a computer simulation of light passing through
> various aerosols, and the scattering that results? It would be great
> to be able to show doctored photos of 'geoengineered sky' vs. 'normal
> sky'. Robock pointed out these effects, but it seems that the
> analysis has possibly been limited/flawed.
>
> A
>

> 2009/5/11 John Gorman <gor...@waitrose.com <mailto:gor...@waitrose.com>>

>
> I have to admit I hadnt thought of that aspect of aerosols in the
> arctic.
>
> To Gregory Benfold -What do you think ?
>
> John Gorman
>
> ----- Original Message -----

> *From:* Bonnelle Denis <mailto:DBon...@ra.ccomptes.fr>
> *To:* gor...@waitrose.com <mailto:gor...@waitrose.com> ;
> andrew....@gmail.com <mailto:andrew....@gmail.com> ;
> John Nissen <mailto:j...@cloudworld.co.uk> ;
> geoengi...@googlegroups.com
> <mailto:geoengi...@googlegroups.com>
> *Sent:* Monday, May 11, 2009 9:42 AM
> *Subject:* [geo] Re: Balancing the pros and cons of geoengineering

> <mailto:Denis.B...@normalesup.org>

[xben...@aol.com]

All:

Bonnelle Denis is right that a detailed study of aerosol reflections
needs doing. Someone may wish to use research time on it, but without
any funding it's difficult to mount a determined attack on the many
parameters that need varying.

The issue of particle size demands some actual experiments, to see what
happens to candidate aerosols at the actual altitudes considered. How
much particle growth occurs, under what conditions of humidity,
pressure, etc? What's the true fallout time vs altitude and particle
size? There's a whole agenda here.

I do wonder how much Lowell Wood and collaborators are doing on this,
but Lowell is mum.

Gregory Benford

Ethyl Silicate Dissolved in Aviation Kerosene As a Means of 0D

saving in=2
0costs of construction, relocating populations and lives

2009/5/9 John Nissen &lt;j...@cloudworld.co.uk&gt;

----- From: "Alvia Gaskill" &lt;agas...@nc.rr.com&gt;
To: &lt;s.sa...@ed.ac.uk&gt;;
&lt;rob...@envsci.rutgers.edu&gt;


Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;

=2
0 &lt;j...@cloudworld.co.uk&gt;;

&lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

the earliest=2
0papers I wrote on geoengineering that eventually we

20 capacity of liquid water is significantly higher than that of most

Message ----- From: "Stephen Salter" &lt;S.Sa...@ed.ac.uk&gt;
To: &lt;rob...@envsci.rutgers.edu&gt;
Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;
&lt;j...@cloudworld.co.uk&gt;;

&lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

0Aincluding 1783 Laki and 1991 Pinatubo, show exactly the same

kcal...@ciw.edu &lt;mailto:kcal...@ciw.edu&gt;;
kcal...@stanford.edu
&lt;mailto:kcal...@stanford.edu&gt;

http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1
650 704 7212; fax: +1 650 462 5968

&gt;

--





The University of Edinburgh is a charitable body,
registered in
Scotland, with registration number
SC005336.




 
 
 

&lt;BR

[Mike MacCracken]

First, of course, one would be working to do the reflection only during the
sunlit months, so Sun is a bit higher in the sky. During peak summer, there
is as much solar incident on Arctic latitudes over 24 hours as at the
equator. Yes, at a lower sun angle, but still a lot of solar.

And as to getting the radiation reflected back to space, were the particles
small and having a surface of corner reflectors (as Teller, Wood et al
suggested some years back), all the radiation reflected would go back in the
direction that it came. That would be helpful, although, of course, then
light coming up from the bright surface would also be reflected back down,
so indeed, some work is needed on optimizing the particle (bright on top,
not reflecting on the bottom.

Mike MacCracken

[John Nissen]

Hi all,

In the absense of any figures from you for monsoon failure risk, may I
suggest a maximum probability of 1% of severe failure, causing the deaths of
maximum 1 million people. If such a disaster occurred, the geoengineering
would probably have to be stopped, even if the disaster was not 100%
attributable to the geoengineering. So continued failure would not occur -
at least not as result of geoengineering. Note that it would be continued
failure for several years that could cause over a million deaths.

Now, what is the next severest risk from aerosols, anyone? Or a worse risk?
Ozone depletion?

Cheers,

John


----- Original Message -----

[Andrew Lockley]

John, 

No you may not assume any such thing.  Far, far too low on both % and numbers for a max possible risk.

A

2009/5/11 John Nissen <j...@cloudworld.co.uk>

[xben...@aol.com]

Since nobody knows, estimates are pointless without better data,
simulations etc

Gregory

-----Original Message-----
From: Andrew Lockley <andrew....@gmail.com>
To: John Nissen <j...@cloudworld.co.uk>
Cc: geoengineering <geoengi...@googlegroups.com>
Sent: Mon, 11 May 2009 3:29 pm
Subject: [geo] Re: Balancing the pros and cons of geoengineering

John, 
No you may not assume any such thing.  Far, far too low on both % and
numbers for a max possible risk.
A

2009/5/11 John Nissen &lt;j...@cloudworld.co.uk&gt;

Hi all,



In the absense of any figures from you for monsoon failure risk, may I
suggest a maximum probability of 1% of severe failure, causing the
deaths of maximum 1 million people.  If such a disaster occurred, the
geoengineering would probably have to be stopped, even if the disaster
was not 100% attributable to the geoengineering.  So continued failure
would not occur - at least not as result of geoengineering.  Note that
it would be continued failure for several years that could cause over a
million deaths.




Now, what is the next severest risk from aerosols, anyone?  Or a worse
risk? Ozone depletion?



Cheers,



John





----- Original Message ----- From: "John Nissen"

&lt;j...@cloudworld.co.uk&gt;

To: "Alvia Gaskill" &lt;agas...@nc.rr.com&gt;;

&lt;s.sa...@ed.ac.uk&gt;; &lt;rob...@envsci.rutgers.edu&gt;


Cc: &lt;kcal...@dge.st

anford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;

&lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

Sent: Saturday, May 09, 2009 11:37 PM

Subject: Re: [geo] Re: Balancing the pros and cons of geoengineering






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=2
0of 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"

&lt;agas...@nc.rr.com&gt;

To: &lt;s.sa...@ed.ac.uk&gt;; &lt;rob...@envsci.rutgers.edu&gt;

Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;

&lt;j...@cloudworld.co.uk&gt;; &lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

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 some20reason, Laki caused this to be muted.

0A&lt;S.Sa...@ed.ac.uk&gt;

To: &lt;rob...@envsci.rutgers.edu&gt;

Cc: &lt;kcal...@dge.stanford.edu&gt;; "Andrew Lockley"
&lt;andrew....@gmail.com&gt;; &lt;XBen...@aol.com&gt;;
&lt;j...@cloudworld.co.uk&gt;; &lt;geoengi...@googlegroups.com&gt;;
&lt;Brian....@manchester.ac.uk&gt;; &lt;sam.c...@gmail.com&gt;;
&lt;pw...@cam.ac.uk&gt;

kcal...@ciw.edu &lt;mailto:kcal...@ciw.edu&gt;;
kcal...@stanford.edu


&lt;mailto:kcal...@stanford.edu&gt;

http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab

+1 650 704 7212; fax: +1 650 462 5968

&gt;

[Dan Whaley]

John,

This is really flimsy thinking.  It springs from a WAG (wild-ass-guess) type analysis of risk--"i.e. If it's not a lot, then it must be a little".  For a humorous take on this, watch Jon Stewart's daily show last week on the LHC (Large Hadron Collider).  I think it's about 19 minutes in.   There is a debate about whether there is a 50% risk of a "black hole" swallowing the earth vs a zero percent chance.

http://www.hulu.com/watch/70872/the-daily-show-with-jon-stewart-thu-apr-30-2009#s-p1-so-i0

More importantly though, it's also really perilous thinking.  The press will pick this up as something akin to: "scientists planning experiment that might kill 1 million people."  etc etc.

Unless you have some rigorous modeling behind your position, I'd suggest refraining from these kind of hypothetical guesstimates.

D

[Ken Caldeira]

It is all about risk reduction.

You cannot say how much risk we would be willing to accept from a climate intervention without first characterizing the risk of not intervening in climate.

If it is clear that a climate intervention would reduce risk (taking into account relevant distributional issues), then it would make sense to consider deployment, regardless of the levels of absolute risk.

___________________________________________________
Ken Caldeira

Carnegie Institution Dept of Global Ecology
260 Panama Street, Stanford, CA 94305 USA

kcal...@ciw.edu; kcal...@stanford.edu

http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab
+1 650 704 7212; fax: +1 650 462 5968  

[Ron]

Debate, analysis, and modeling of the status quo and thought experiments should be continuous. The more the better.

-----Original Message-----
From: Andrew Lockley

Sent: May 11, 2009 6:29 PM
To: John Nissen
Cc: geoengineering
Subject: [geo] Re: Balancing the pros and cons of geoengineering

John, 

No you may not assume any such thing.  Far, far too low on both % and numbers for a max possible risk.

A

2009/5/11 John Nissen <j...@cloudworld.co.uk>

[John Gorman]

Although I was initially worried by Denis's point that arctic aerosols will
capture some rays that would otherwise just pass tangentially through the
stratosphere, I have now done some geometry and believe that this will only
apply to about 0.2% of the incident sunlight on the Arctic at midsummer.

This is because the atmosphere is thin in comparison with the radius of the
earth.

This applies of course to all aerosols SO2 or SiO2. My main argument for
suggesting silica (Greg's diatoms) is that we might be able to control
particle size much more exactly.

[Bonnelle Denis]

I agree that my point wasn't considering seasonal changes in the earth's orientation relatively to the sun rays (I was in fact dealing with equinox times), and that mid-summer conditions are much more favorable for the most polar locations.

However, at each time of the summer, there exist locations where the lowest point of the sun's daily trajectory is very low above the horizon, and in such locations the effect of aerosol creation would be a notable increase in the received luminous power during several hours around midnight. It is far from sure that this would be offset by the reduction in the received heat around midday (remember my point that a tangential ray would propagate through many hundreds km of the stratosphere, when an oblique one would only get through some tens km or air).

At mid summer (and during at least several weeks before and after the 21st of June), these "dangerous" locations are the ones just north of the arctic polar circle (a central slice of Greenland, and lands near the Northern coasts of Canada and Siberia - mind the permafrost).

If these regions are to be avoided, would it be possible to control very precisely the location (are there significant shifts of air masses from one latitude of the stratosphere to another?) and the time (the particle size control issue) of the aerosols to be created?

Denis Bonnelle.

-----Message d'origine-----
De : John Gorman [mailto:gor...@waitrose.com]
Envoyé : mardi 12 mai 2009 11:25
À : XBen...@aol.com; Bonnelle Denis; geoengi...@googlegroups.com
Objet : Re: [geo] Re: Balancing the pros and cons of geoengineering

[Andrew Lockley]

You'd have to calculate this across the whole globe, surely?  If the whole atmos was affected, then this would mean the Earth turned from being a sharp round disc to a bigger, hazy one?   But, the evidence from Pinatubo surely demonstrates that this doesn't cause a problem, it still cools down.

However, can I ask if the backscattering from reflected light has been considered?  Over the tropics, where it's not snowy, this is not very important, but over the ice, where about 90pc of the light comes back, then it's massively important and (seems to) cancel out 90% of the aerosol's effects (you'd have to iterate that a few times, of course).  That tangental ray effect could then end up being very significant, and if it's more than 10% of the net effect then aersols will heat, not cool the arctic.

Or perhaps I'm just being thick.

A

2009/5/12 Bonnelle Denis <DBon...@ra.ccomptes.fr>

[Mike MacCracken]

A couple of points:

1. On the angle issue, this is of course taken into consideration in calculating how much solar radiation reaches the Arctic at any given time—and rays just passing tangentially through will not count much at all. That the actual incident light in high latitudes in summer, integrated over the day, is roughly as much as at the equator (William Sellers book of roughly 4 decades ago on climate has a nice diagram) means that there is plenty of time when aerosols could backscatter solar radiation to space.
2. On the backscattering from reflected light, roughly speaking sulfate aerosols forward scatter about ten times as much as they back scatter. That would likely still be the case for the upward scattered radiation. The cancellation would only then occur if the surface albedo were about 1, and if it is this high, then we should not be using aerosols anyway as the natural system is doing just fine on its own. The time to use aerosols is when the surface-troposphere albedo is dropping lower, so the cancelling effect would be smaller. And I don’t think one would have to do the mentioned iteration, again, unless the surface-troposphere albedo is high. I guess what would be really nice to have is a particle that has a corner reflector on top (so perfect reflection with no scattering) and is absorbing below, so the energy is taken up high in the atmosphere where most is likely to be radiated to space by the layer’s CO2 (some does go down, but one is above most of the water vapor, so its GH effect is very small).
   

Mike

[Alvia Gaskill]

The amount of total downwelling solar reflected back to space depends on the total albedo of the surface, not just that for visible light.  During the Arctic spring and summer, large areas of the Arctic ocean are ice free, meaning that the blue water will absorb nearly all of the sunlight.  The 90% figure only applies to fresh snow and includes all solar radiation, not just visible.  Ice albdeo can be as low as 40% and old snow somewhere in between.  Remember also that only about 47% of downwelling solar is visible light.  The remainder is UV and solar IR, neither of which are visible.  Any kind of aerosol or engineered particle must take that into account as well. 

 

The experience with Pinatubo was that the aerosol was less effective in reducing downwelling solar in the Arctic than in the tropics or midlatitudes because at high latitudes, there is more cloud cover.  I think the cloud cover will be a much more important issue than forward scattering of sunlight.  

 

One also has to consider the total amount of solar radiation received and not just that from a few hours of the day.  The sunlight coming in at a low angle is already scattered a lot vs. that when the sun is higher in the sky.  That's why you can get a sun burn very easily at noon, but it takes a lot more exposure late in the day to do so.  So the result of blocking out part of the sky with aerosols or particles will be less warmth and not more.

[John Nissen]

 

Hi Ken,

 

Absolutely right.  It's a risk reduction exercise.  So we have to balance risk of not geoengineering (which quantifies the main benefit, i.e. avoiding the danger from sea ice retreat) with the risk of geoengineering.  Thus we have to have some estimate of the magnitude of the risks.  If the risk of not geoengineering clearly outweighs the risks of geoengineering, then it is our duty to say so, clearly, to policy makers.

 

I used Alan Robock's list of specific fears of geoengineering, with stratospheric aerosols in polar regions.

 

Specific fears of stratospheric aerosols (from Robock [2]):

 

S1.  Could have adverse effect on some regional climate(s) and ecosystem(s) [4]

S2.  Doesn't help with ocean acidification.

S3.  Ozone depletion.

S4.  Effect on plants (but more diffuse light has positive benefit?)

S5.  Acid rain (withdrawn)

S6.  Effect on cirrus clouds.

S7.  Disappearance of blue skies (and appearance of red sunsets?) could have negative psychological impact.

S8.  Less sun for solar power.

S9.  Environment impact of implementation (e.g. if put sulfur in jetliners fuel).

S10.  If stop, previously suppressed global warming will spring back to hit you.

S11.  Cannot stop quickly enough, if you did need to.

S12.  Human error, with means of delivery, causing dreadful accident.

S13.  Moral hazard = G3.

S14.  Cost = G6

S15.  Commercial control of technology

S16.  Military use of technology

S17.  Conflict with current treaties

S18.  Control of the thermostat

S19.  Questions of moral authority  

S20.  Unexpected consequences = G10.

S21.  Ruin astronomical observations

 

On S1 (about regional effects), taking into account Alan Robock's paper and our discussion on this thread, it seems that weakening of Indian monsoons is the particular concern, and I have personally estimated maximum risk using 1% probability and 1 million lives.  Andrew Lockley suggests that is far too low, so I'd welcome an estimate from him and from others.

 

On S2 (ocean acidification), we all know that attempts to save the Arctic sea ice are irrelevant to ocean acidification.  However, cooling the ocean will allow more CO2 absorption with a slight acidification effect.  Should we assume that CO2 levels will be reduced before ocean acidification becomes any kind of risk for SRM geoengineering?  As the open letter to Dr Pachauri suggests, SRM geoengineering should be done in parallel with mitigation and carbon stock management to reduce CO2 levels.

 

On S3 (ozone), we have already discussed the ozone depletion hazard.  Some think that the risk is quite low (e.g. compared to S1), providing the aerosol precursor is launched in spring, such that most has dropped out by the following winter.

 

On S4 (diffusion), we agree that there could be a net benefit, due to diffuse illumination on plants.

 

On S5 (acid rain), Alan has withdrawn, having done some modelling - see the paper he's just sent us.  Does anybody still have concerns?

 

On S6 (effect on cirrus clouds), any comment?

 

On S7 (psychological), there really can be no quantifiable risk, can there?  Nobody needs to lose sleep!

 

On S8 (solar power), we could calculate a small effect on solar power generation.  But this would be small in the Arctic, and it is not going to cost lives. 

 

On S9 (implementation), the environmental risk is negligible, especially if we use balloons for deployment.

 

On S10 (if stop...), it has been suggested that, if geoengineering is stopped, the global warming will not jump to higher than if the geoengineering had not taken place.  In the case of Arctic geoengineering, the effect will be less.  Moreover we might be able to phase the geoengineering out, if the sea ice retreat can be reversed. 

 

On S11 (stopping quickly), we've discussed being able to stop the geoengineering.  This could be effectively done within about 9 months.  The plan would be to launch the aerosol precursor in March/April, when the stratosphere has started to warm up (avoiding danger of ozone depletion when stratosphere at its coldest).  The deployment parameters (such as elevation) would be adjusted such that most of the aerosol would have left the atmosphere by the following winter.

 

On S12 (human error), what kind of human error, with means of delivery, could cause a dreadful accident?  An airliner flying into a balloon? 

 

On S13 (moral hazard), we have already discussed the moral hazard, as not coming into the risk calculation (see G3).

 

On S14 (cost), it has been estimated the cost would be less than $1 billion per year, perhaps a lot less.  Can we put that figure as the maximum financial risk for the deployment? 

 

On S15. Commercial control of technology is unlikely, as there is no money to be gained.

 

On S16. Military use of technology is possible with almost any technology.  Can we estimate a risk on this?

 

On S17. If there is a conflict with current treaties, that is not a danger of geoengineering, but a danger of not being allowed to geoengineer.  So I suggest we treat it as a factor on the benefit side, affecting the probability of geoengineering success.

 

On S18 (control of the thermostat), we'd have to agree in advance on how far the deployment should go, and the criteria for halting.

 

On S19 (moral authority)  The question of moral authority should not be of concern, if the net benefit of geoengineering is clear.  The moral question would then be about not geoengineering.  (What are the ethics of standing in the way of a means of reducing the risk of a total catastrophe such as runaway global warming from methane release?)

  

S20.  Unexpected consequences are minimised because of knowledge from Pinatubo and from tropospheric aerosols.

 

S21.  SRM might degrade astronomical observations, but it's not going to cost lives.

 

------

 

Thus S1 (weaker Indian monsoon) seems to be the most significant risk from deploying the stratospheric aerosol geoengineering in the Arctic, in terms of lives and GDP put at risk.  Can we obtain a consensus on this?

 

Any comments?

[Andrew Lockley]

Close on 1bn people rely on S. Asian monsoon systems for food.  I'd suggest that you look at the global food production dip that occurs in such circumstances, and the elevated death rates for such years, and then string them out for as many years as you expect to find the effects active.  You need to bear in mind food reserves too, as people tend to store enough food to get round 1 bad harvest, but several in a row could be a mass killer.  You have to look at the effect the production dip would have on the death rate, and not just extrapolate the death rate by a few years.

Maybe the Indian Embassy, or an Indian University, would be a good place to start?  You'd also be well placed chatting to the Liverpool group who've been modelling the monsoon.  Maybe looking at getting them onto this list would be wise.

There's no evidence I can see for suggesting a 1% risk of monsoon failure.  Where's the evidence?  Why not 99%?

A

PS On an admin note, please can people not cc people who are already on this list?  I'm sure they don't need the emails twice.

2009/5/12 John Nissen <j...@cloudworld.co.uk>

[Alvia Gaskill]

S1. I don't see how you came up with 1 million people at risk from Arctic aerosol geoengineering.  The problem if any is not that the monsoons won't come, they still will, but as you note, they may be weaker, resulting in less rainfall.  The region is used to wide swings of 50% or more, but the problem would become more relevant if precipitation were reduced permanently by 10-25% or maybe not.  I don't know what such a reduction would mean long term and whether or not adjustments could be made (Schnare mentioned some of these issues recently). 

 

I think it unlikely that a 10% reduction would kill 1 million Indians the first year or the second or even the 10th.  Because this is such a complicated question, it has to be addressed by experts in the relevant fields.  Of course, if the comparison comes down to saving 7 billion vs. not saving 7 million, the answer is obvious.  We just don't want it to get to that point.

 

BTW, the weakening of the monsoon modeling was based on the presence of year-round stratospheric aerosols, not tropospheric as Benford has proposed.  We have no idea what effect that would have on weather patterns in Africa and Asia if any at all.  We have to be careful to compare apples to apples.  Laki was mostly a tropospheric event and did lead to monsoonal decreases, but it also had a stratospheric component and was far larger than anything that could be conceived for the Arctic strategy.

 

S2.  Actually, factoring in possible feedbacks involving permafrost, attempts to save Arctic sea ice could very well slow ocean acidification.

 

S3.  It is still unclear that the aerosol will be gone before the Arctic winter begins.  That is a theory, not a fact.  I would be more concerned that it won't stay airborne or in the right place long enough given the tropospheric winds.  The pattern for Arctic stratospheric is that the aerosol spreads southward, requiring a lot more than that just needed to block X amount of sunlight over the Arctic.  I don't think there is enough information to determine the spread pattern for upper tropospheric aerosols in the quantities desired.  Aerosol in the upper troposphere (LMS) would have some possible effect on ozone, but not as much as if it were also in the Overworld.

 

S5.  Not mentioned in his paper, but in one of my postings on an earlier draft, acid rain monitors in the NE U.S. showed no effect during Pinatubo, so it's pretty certain there is no hazard.

 

S9.  Jet fuel cannot  be altered, so this is not an issue.  There would be a carbon footprint from balloons, as the hydrogen would come from reforming of natural gas. 

 

S11.  Since the aerosol lifetime in the Arctic tropospheric scenario is on the order of weeks to a few months and precursor or particles would have to be released incrementally, I don't see how it would be difficult to stop or why it would take 9 months, unless you are assuming precursor released in March would last until December.  The actual ozone destruction takes place in the spring and requires sunlight to complete the process.

 

S16.  There is no military application, thus no risk.  It's funny how the people opposed to geoengineering always bring this up, yet the same people point out all the ways it won't work as designed.  Military planners don't want to use an uncertain weapon.  The people who make the military argument have a political agenda and use it to play on the fears of a public that is very distrustful of government thanks in part to the last 8 years.

 

S17.  The treaty on weather modification is about military use so it is not relevant.  More likely, treaties dealing specifically with the Arctic would become an issue.

 

S21.  Not too many observatories north of the Arctic Circle.

 

On the whole, I think running through this and similar lists and revisiting them periodically as we learn more is a good exercise.

[John Gorman]

As you say, pinatubo etc. prove that stratospheric aeroslols would cool the world and it is therefore the disadvantages that we have to evaluate.

 

Many of us see the greatest and most urgent dangers in the Arctic and Antarctic and think that localised stratospheric aerosols would probably avoid serious ice sheet loss, sea level rise and release of methane- to name but three problems. This is where these new questions become important and need real funded research as Greg said.

 

So far I cant see anything to suggest it wouldnt work.

 

John Gorman

----- Original Message -----

From: Andrew Lockley

To: dbon...@ra.ccomptes.fr

[Bonnelle Denis]

Dear all,

attached is a first attempt to compute something about the possible efficiency reduction, due to geometrical reasons (light scattering from tangential sun rays), of an aerosol stratosphere spreading project which would be specifically targeted to the Arctic alarming climate issues.

The results are that, with the assumption of some hypotheses, this geoengineering project's efficiency could be reduced by a punctual maximum around -38 % (midsummer, 63°N), and mean values (both among some weeks and some hundreds km around the maximum point) could be reduced by approximately -30 %.

It could be even worse if some of the used hypotheses wouldn't be met, particularly:

-if the scattering was anisotropic, with a larger part of the light diffracted only some degrees around its incident direction;
-if there were more clouds around midday than around midnight;
-if aerosols had a greenhouse effect.

Best,

Denis Bonnelle.


-----Message d'origine-----

De : Bonnelle Denis
Envoyé : mardi 12 mai 2009 12:07
À : 'John Gorman'; XBen...@aol.com; geoengi...@googlegroups.com
Objet : RE: [geo] Re: Balancing the pros and cons of geoengineering

I agree that my point wasn't considering seasonal changes in the earth's orientation relatively to the sun rays (I was in fact dealing with equinox times), and that mid-summer conditions are much more favorable for the most polar locations.

However, at each time of the summer, there exist locations where the lowest point of the sun's daily trajectory is very low above the horizon, and in such locations the effect of aerosol creation would be a notable increase in the received luminous power during several hours around midnight. It is far from sure that this would be offset by the reduction in the received heat around midday (remember my point that a tangential ray would propagate through many hundreds km of the stratosphere, when an oblique one would only get through some tens km or air).

At mid summer (and during at least several weeks before and after the 21st of June), these "dangerous" locations are the ones just north of the arctic polar circle (a central slice of Greenland, and lands near the Northern coasts of Canada and Siberia - mind the permafrost).

If these regions are to be avoided, would it be possible to control very precisely the location (are there significant shifts of air masses from one latitude of the stratosphere to another?) and the time (the particle size control issue) of the aerosols to be created?

Denis Bonnelle.

-----Message d'origine-----
De : John Gorman [mailto:gor...@waitrose.com]
Envoyé : mardi 12 mai 2009 11:25
À : XBen...@aol.com; Bonnelle Denis; geoengi...@googlegroups.com

Objet : Re: [geo] Re: Balancing the pros and cons of geoengineering

[John Nissen]

 

Hi Alvia,

 

A good exercise.  Thanks, Alvia.  That just about completes the downside on Arctic aerosol geoengineering.

 

Re S1, if anything, cooling by aerosol will go counter to the undesirable effects of climate change:

http://www.scidev.net/en/news/indian-monsoon-intensified-by-climate-change.html

so I will side with you, Alvia, on having a much lower monsoon risk that I had suggested for S1.

 

If other risks (S2-S21) are smaller than S1, by general agreement, then we can go onto the benefit side:

 

B1.  Save the Arctic sea ice and associated ecosystem.

B2.  Slow (and preferably halt) Arctic warming. 

B3.  Reduce discharge of CO2 and methane, contributing to global warming and ocean acidification.

B4.  Reduce risk of massive methane discharge, sufficient to add several degrees of global warming. 

B5.  Slow the rise in sea level from Greenland glaciers.

B6.  Reduce risk of Greenland ice sheet destabilisation, and associated 6 metres of sea level rise.

B7.  Develop the SRM techniques to use at other latitudes.

 

Re B1, the risk of the sea ice seasonal disappearance is of concern, mainly because of the likely effect on Arctic temperature (see B2 and B3-B6).   The value of the ecosystem is difficult to estimate, but not negligible, because of marine food chains.  Some experts are predicting the most likely date for end-summer disappearance as around 2030, but with a significant possibility of this happening much sooner.

 

Re B2, to completely halt the Arctic warming, we need enough negative forcing to counteract the positive feedback that is building up all the time.  

 

Re B3, as you (Alvia) noted, SRM geoengineering could have a positive impact on global warming and ocean acidification by halting the release of CO2 and methane in the Arctic.

 

Re B4, this is the real killer.  There is massive quantities of methane trapped in frozen structures.  If there were sufficient discharge, it would added significantly to global warming (the global warming obtained from anthropogenic CO2), and then this would provide positive feedback, since the additional global warming would cause further methane discharge, and we could get a thermal runaway effect leading to abrupt climate change and global warming of many degrees, not survivable for civilisation by any stretch of the imagination.  Everyone's life would be at risk.  Initially the infrastructure of wealthy nations would collapse, so they'd be hit as hard as poorer nations, but then there would be global food shortages, etc. etc. (For contemplation of the abyss, read Jared Diamond's book "Collapse".)

 

Re B5, we are already seeing sea level rising faster than predicted by IPCC, who forecasted a rise of less than 0.5 metres this century.

 

Re B6, we could get 6-7 metres (~21 feet) from Greenland, and at least as much again from Antarctica.  Professor Hansen has even spoken of 25 metres being possible by end century. [Ref?]

 

Re B7, the Arctic could prove an excellent proving ground for SRM geoengineering.

 

So we have incredible benefit from stratospheric aerosol geoengineering if it can succeed in reducing the risks associated with Arctic sea ice loss.

 

What is the probability of failure?

[John Gorman]

I think those of us promoting local stratospheric aerosols to save the
Arctic should take seriously this subject raised by Denis.

It's about the increase in radiation on the area under tangential rays that
would otherwise just pass through the atmosphere.

Initially I thought this efect would be about 0.2% I got this figure by
comparing the area of the elipse of the Arctic as seen from the sun (at
midsummer) with the small cresent of Arctic atmosphere above the earth .also
as seen from the sun.

However I didnt consider that these tangential rays are passing through
about 1000km of atmosphere and it is reasonable to assume that all this
light will be reflected/defracted over this distance, not just 5%

If we add this multiplying factor of 20 or so, this small area has a
significance of about 4% in comparison with the whole Arctic area . This is
the same order of magnitude as the reduction in light that we are hoping for
in the first place so are we gaining anything?

Looked at in adifferent way. At Arctic midsummer atmospheric aerosol 20km
high will affect a band about 1000 km in latitude centred on the Arctic
circle. This same band at midday will be about 700km high as seen from the
sun (sin45); 700 divided by 20 is35 times as much incoming sunlight (at
midday as compared with midnight) but again we have to compare the 5%
dispersion at midday with 100% at midnight so 35/20 = only a factor of 2
now.

So for any area in the 1000 km band we are gaining very little in net
radiation reduction.

I have to admit I couldnt follow Denis's calculations (attached) but my own
attempts here give similar results. And as Denis hints, this is going to be
the most important area where melting is greatest-like South Greenland!

Has anyone done any work on this before? Any papers? Have we both got the
geometry wrong? It is quite difficult to think about.

help!

[Alvia Gaskill]

I started a different thread on this as my email service gagged on the size of the 60+ responses to the original.  Since Ken hid the membership lists for both groups, I no longer know who is or isn't a member, so I will continue to copy those on the original posting. 

 

I am also having some trouble following this argument, but note that the Pinatubo aerosol DID reduce forcing over Greenland and the Arctic.  The sea ice in 1992 was the thickest of any of the last 20, I believe.  So it wasn't cancelled out by forward scattering of tangential rays.  Therefore, there must be some kind of error in the calculations or assumptions.

 

There is also some confusion, I believe in what we are calling "stratospheric aerosols" over the Arctic.  The Pinatubo aerosols were in the Overworld stratosphere, the stratosphere above the altitude of the tropical tropopause (>53,000 ft.)  Benford's proposal along with others that seek to have the aerosol descend and be gone before the Arctic winter involves "tropospheric aerosols" or other sunlight scattering materials.  The altitude at issue here has never been clearly stated, but I assume it is to be around 40,000-45,000 ft, close to the magic 53,000, but not above it and high enough to guarantee aerosol lifetimes of several months.  If you want to use airplanes like the 747, the KC-135, the "extender" or even the B-52, that's about as high as you are going to be able to go.

 

Even though various people over the last several years including myself have talked about 40,000-50,000 ft as an altitude at which aerosol lifetimes are in the months and not years, I'm not aware of any studies that confirm this.  Add to this the fact that in the Arctic, the stratospheric air is descending and not rising, so even at above 53,000 ft, this fact, coupled with removal of aerosol via tropopause folding makes the lifetimes uncertain.  If, for example, a true "stratospheric" aerosol program is carried out above the Arctic circle, the litetimes of these aerosols will likely be less than those produced in the tropics, perhaps only 6 months instead of 12 or 18.

 

The recent volcanic eruptions in Alaska (Redoubt and Kasatochi) are good examples of what may actually happen with tropospheric areosols. 

 

http://www.avo.alaska.edu/volcanoes/volcact.php?volcname=Kasatochi&eruptionid=605

 

"The eruption was characterized by three distinct explosions that were detected by the seismic network on Great Sitkin Volcano, at approximately 2:01 PM, 5:50 PM, and 8:35 PM AKDT. The first two events produced relatively ash-poor, but gas-charged, eruption clouds that reached 45,000 - 50,000 feet above sea level and apparently no or very little local ash fall. The third event generated an ash- and gas-rich plume that also rose to 45,000 - 50,000 feet and produced several inches of ash and lapilli fall over the ocean and on islands southwest of Kasatochi, including minor amounts on Adak Island, the closest island with a year-round population, about 50 miles from the volcano. Boats in the vicinity of the volcano reported 4-5 inches of coarse grained ash fall, darkening skies, and lightning, likely caused by static electricity in the ash plume. The third event was followed by about 17 hours of continuous ash emission as determined from satellite data. The cumulative volcanic cloud from Kasatochi (Fig. 1) contained a large amount of sulfur dioxide gas that was detected by the Ozone Monitoring Instrument on NASA's EOS-Aura satellite for more than a week after the eruption as the cloud circled the globe. The ash and gas cloud drifted east and interfered with air travel between Alaska and the conterminous US causing at least 40 flight cancellations and stranding many thousands of travelers. The cloud was visible for thousands of miles downwind and apparently was the cause of some brilliant sunsets over the Midwestern US.

http://www.avo.alaska.edu/image.php?id=15049

 

This shows the spread of the SO2 from Kasatochi last August.  Approx. 1.2 Mt of S were injected into the altitude range from 35,000-45,000 ft.  Below 53,000 ft, the winds tend to blow from west to east and the reverse is true above 53,000 ft.  Note the irregular pattern of dispersal, the southern reach into Missouri and Iowa and how, coincidentally perhaps, none of it made it to Greenland or the Arctic sea.  Can we expect any better spread with a manmade release over the Arctic?  Granted, Kasatochi is at 52N, so a true Arctic program would likely be carried out farther north. 

 

The excerpt from the website notes that the satellite only detected SO2 for about a week after the eruption, but since it only measures SO2 and not H2SO4, the fate of the SO2 is unknown.  I think most of it descended as aerosol within a few days over the Atlantic and had little or no effect on solar forcing as the spread pattern looks suspiciously like that of typical west-to-east weather fronts that begin to show up in August. 

 

Alan stated that this eruption showed that there is no clear threshold for a climate impact from aerosols as 1.2Mt of S from this one had none.   As I previously noted and as the reporting on this eruption show, this eruption is irrelevant to making such predictions for a stratospheric aerosol program.  Pinatubo's 6Mt of stratospheric S caused a global temperature decrease of about 1 degree F, so as a crude approximation, 600Kt of S similarly dispersed should decrease temperature by 0.1 degree F if the relationship is linear.  Temperature variations smaller than this are measureable, but due to the lack of volcanic eruptions reaching the stratosphere in recent years, there hasn't been enough data to confirm the actual temperature/S burden relationship.  Ditto for other effects on climate such as precipitation and stream flow.

 

Mt. Laki did produce both tropospheric and stratospheric aerosols and was more like what a human program would resemble with incremental injections, but the total mass of S was much greater than what we could do and I would have to review the data for this eruption more closely to see if much of the stratospheric was also the result of tropopause folding (the air goes in both directions).

 

 

Composite satellite image from August 12 showing the sulfur dioxide cloud produced by the August 7 eruption of Kasatochi. This cloud circled the northern hemisphere between 35,000 to 45,000 feet above sea level. Colors represent relative amount of gas with dark orange being the highest and dark blue the lowest. These data are from NASA’s EOS-Aura satellite and its Ozone Monitoring Instrument (OMI), courtesy of Dr. Simon Carn, University of Maryland, Baltimore County.

Picture Date: August 12, 2008
Image Creator: Schneider, Dave;

Image courtesy of AVO/USGS.
Please cite the photographer and the Alaska Volcano Observatory / U.S. Geological Survey when using this image. Data provided by the OMI near-real-time project funded by NASA.

[xben...@aol.com]

Alvia:

You're right:

"There is also some confusion, I believe in what we are calling
"stratospheric aerosols" over the Arctic. The Pinatubo aerosols were
in the Overworld stratosphere, the stratosphere above the altitude of
the tropical tropopause (>53,000 ft.) Benford's proposal along with
others that seek to have the aerosol descend and be gone before the
Arctic winter involves "tropospheric aerosols" or other sunlight
scattering materials. The altitude at issue here has never been
clearly stated, but I assume it is to be around 40,000-45,000 ft, close
to the magic 53,000, but not above it and high enough to guarantee
aerosol lifetimes of several months. If you want to use airplanes like
the 747, the KC-135, the "extender" or even the B-52, that's about as
high as you are going to be able to go."

I originally thought of the 40,000-45,000 ft site, but as you say, this
demands some real measurements. That's what early, small field tests
with tracer aerosols can discover.

It's clear that research might usefully break down into distinguished
phases:

1. Lab development.
How do aerosols deploy and evolve in stratospheric conditions?
How to deploy them? Where? What level? etc
Do these in high vacuum chambers such as the JPL 3-story one, which can
adjust gas pressure and temperature. Most lab experiments are wall
dominated and not useful for real numbers. But nozzle design, local
chemistry etc can be done in them. (There's a group at NASA Ames that
does this. And others, too--but those I know because I looked into
doing this work there.)

2. Local Field Tests
The Arctic stratosphere begins in the 8 to 10 km range, easily reached
by the KC-10 Extender. This midflight refueler is about to be replaced,
so plenty are available and well understood, with experienced pilots. I
calculate that a test in the Arctic over roughly 150 mile perimeters
would give decent diagnostics of the main parameters -- descent time,
spreading rate, temperature changes, chemistry, etc.

I think regional, local tests can be done quietly and well for low
cost. To truly try to cool a small region of the Arctic, after due
diplomacy with the Arctic Council (and only them), could cost well
under $ 100 million.

3. Cooling the whole Arctic would be best to hand off to a civilian
agency, costing about 1 $ billion/year. NOAA satellites, Arctic Council
measurements on their territories, and in situ measurements in the
stratosphere and troposphere, would be essential. Sea ice is the best
overall diagnostic tracer.

This agenda we can organize, but until a sea change in attitude occurs,
there's no funding. Calculations of the angular effects,
down-reflection etc, as this list has seen this week, are complex and
need a full study.

Gregory Benford

[Rob]

Regarding:

"Furthermore, existing observing systems for stratospheric aerosols
are
difficult to use. The SAGE satellites are no longer working. There
is
a spare SAGE III on the shelf at NASA, but there are no plans to
launch
it. Calipso lidar can make episodic measurements along very narrow
tracks, but cannot measure the properties we want, like size
distribution."

1. Are there new specifications for sensors from the scientific
community that would better observe stratospheric aerosols than legacy
hardware on orbit?
2. What about existing GPS-RO sensor data from the COSMIC array
(jointly operated by UCAR and NSPO); they are LEO sensors and obtain
enough raw, sample readings on atmospheric perturbations from
ionosphere down to below cloud level to improve severe weather
forecasting and climate research globally (this data is currently
being used operationally and for research by over 800 groups in 47
countries)?

Am not sure if GPS RO offers any efficacy in tracking aerosols and
their size distribution; but, what about commercial options and
private public partnerships instead of simply deferring to government
led missions?

R. Mark Hanna / Founding Partner
www.socialwealthpartners.org
512.476.4920 Austin
415.205.8576 San Francisco

"We help our clients shift from being good at growing philanthropic
organizations and activities to being great at growing the significant
impacts that should result from them.”

[Bonnelle Denis]

Thank you for this good news about Pinatubo and the Arctic. This is not contradictory with the figures I had got: -38 % in the geoengineering efficiency at a particular point and date, -30 % for a larger range of both, which is clearly lower than a -100 % reduction in efficiency.

 

However, I was suggesting particular points of concern, which could worsen these figures, e.g. if the scattering was anisotropic, with a larger part of the light diffracted only some degrees around its incident direction. So, my conclusion is that trying to mimic the Pinatubo requires either to be sure that we use the same type of aerosols, with the same particle size distribution or mean size (diffraction scattering is very sensitive to the size/wavelength ratio), or that precise optics calculations guarantee a similar behavior.

 

Denis Bonnelle.

 

De : geoengi...@googlegroups.com [mailto:geoengi...@googlegroups.com] De la part de Alvia Gaskill
Envoyé : vendredi 15 mai 2009 17:47
À : j...@cloudworld.co.uk; kcal...@stanford.edu; dan.w...@gmail.com; Professor Tom Wigley

Cc : geoengi...@googlegroups.com; Brian....@manchester.ac.uk; Sam Carana; Davies, John; Peter Wadhams

Objet : [geo] Geometry, Arctic and Aerosols