Hello Peter et al, It is pleasing to have your support, Peter, for the idea that our maritime cloud albedo enhancement scheme be assessed fully, which of course requires significant funding which has not yet been procured. Despite that major impediment considerable progress has been made on the techological side by Stephen Salter. On the scientific side our recent fully-coupled atmos/ocean GCM modelling is yielding very encouraging results vis-a-vis the potential capacity of the scheme to stabilise the Earth's average surface temperature and hold polar isea-ice cover constant at least up to the 2xCO2 point. So, in principle, the scheme could be of value with respect to both the global problem, and the limited area one that Peter mentions. A paper on this modelling study, by Phil Rasch, Jack Chen and myself is shortly to be submitted for publication.
We stress, however, that crucial technological and scientific questions remain to be addressed, and that the scheme could founder if satisfactory resolutions of them is not achieved. Procurement of funding is vital in this regard. The GCM studies also address the issues of the ramifications of possible deployment of this scheme, but this work is currently at a very early stage. Cheers, John. Quoting Peter Read <[email protected]>: > This correspondence is all very interesting and S aerosol cloud > albedo modification, though having some risks, needs to be researched > as a stand-by, as Ken says (along with John Holdren in his more > unguarded moments). > > What I cannot understand is the continuing silence/lack of interest > in the regionally specific ((e.g. cool the gulf stream to make sure > it keeps on sinking somewhere round Iceland, cool tropical waters > upstream of coral reefs and in the regions of hurricane formation, > any other ideas??)) scheme for cumulus cloud albedo modification over > the oceans proposed by Salter and Latham. So far as I can see the > greatest side effect is slightly salty rain falling into the oceans. > Wow. Maybe some tele-climatic effects that climate modellers can > assess but in the meantime wouldn't it be a good idea to do some > engineering hardware research to see if the scheme actually works? > > Peter > ----- Original Message ----- > From: Ken Caldeira > To: [email protected] > Cc: geoengineering > Sent: Tuesday, April 21, 2009 11:03 PM > Subject: [geo] Re: EGU meeting, April 19-24 > > > For future sulfur emissions, see > http://www.ipcc.ch/ipccreports/sres/emission/5-20.htm > > For past sulfur emissions, see the attached paper. > > Current sulfur emissions are on the order of 50 Tg/yr and for this > half century is likely to be in the range of 50 to 100 Tg/yr. > > The EGU abstract > (http://meetingorganizer.copernicus.org/EGU2009/EGU2009-4831.pdf) > foresees emissions rates of 5 to 10 Tg/yr for the first half of the > century, which is roughly the 10% range of current emissions, with > this percentage scaling up if greenhouse gas concentrations continue > to increase and tropospheric sulfur emissions decline. > > So, this is not negligible, but it is unlikely to be a game changer either. > > It is my view that there would need to be some mighty compelling > reasons to deploy a stratospheric aerosol system, if not only because > people who experience bad weather in subseuqent years might be > incented to sue (or even attack militarily) parties engaged in > aerosol release. > > So, if we in an emergency situation acid rain, ozone loss, etc > would be among the costs taken into account before making a decision, > but these costs may not be decisive. > > I still think Mt Pinatubo is the poster child for stratospheric > aerosols approaches: We know it can cool the Earth, we know it can > do this quickly, and we know it does not immediately cause a global > catastrophe. Were we faced with a real climate emergency, there could > be a lot of pressure to exercise the Pinatubo option. I do not see > that the abstract by Eliseev et al markedly changes this picture. > > Best, > > Ken > ___________________________________________________ > Ken Caldeira > > Carnegie Institution Dept of Global Ecology > 260 Panama Street, Stanford, CA 94305 USA > > [email protected]; [email protected] > http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab > +1 650 704 7212; fax: +1 650 462 5968 > > > > > On Mon, Apr 20, 2009 at 4:16 PM, John Nissen <[email protected]> wrote: > > > Some items from the EGU programme > > Cryosphere - how much longer? > > This should be an interesting session: > http://meetingorganizer.copernicus.org/EGU2009/oral_programme/142 > > Also on cryosphere is the session chaired by Peter Wadhams: > http://meetingorganizer.copernicus.org/EGU2009/oral_programme/196 > > And some potentially interesting presentations here: > http://meetingorganizer.copernicus.org/EGU2009/oral_programme/702 > and here: > http://meetingorganizer.copernicus.org/EGU2009/oral_programme/706 > > Geoengineering, session CL27 > > There seems to have been a disappointing response for this > session. However the session does include a poster presentation > from Russians on SRM using stratospheric sulphur aerosols: > http://meetingorganizer.copernicus.org/EGU2009/EGU2009-4831.pdf > I'd be interested in Ken Caldeira's comments on this. > > Carbon stock management > > In "carbon-constrained future", I see no mention of geoengineering: > http://meetingorganizer.copernicus.org/EGU2009/oral_programme/143 > For example, there is this presentation: > ---- > > Can we control climate change risks and what does it cost? > > B. Metz > > Fellow, European Climate Foundation and former co-chair IPCC > Working Group on Mitigation > > For controlling climate change risks to manageable levels global > emissions of greenhouse gases have to start > > declining by 2015-2020 and need to be reduced to more than 50% > below 1990 levels by 2050. > > An overview will be given of the options that exist to achieve > these very challenging objectives. The economic > > reduction potential of these options will be given as well as > their costs. > > Finally, the policies needed to realize the reduction potential > will be discussed. > > ---- > > There seems little sense of emergency, despite the looming > cryosphere dangers. Disappointing. > > Cheers, > > John > > > > > > > > > > > > > ------------------------------------------------------------------------------ > > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.0.238 / Virus Database: 270.12.1/2070 - Release Date: > 04/20/09 17:56:00 > > > > -- John Latham [email protected] & [email protected] Tel. 303-444-2429 (H) & 303-497-8182 (W) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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