Alan: The correct risk-risk trade-off is the loss of agricultural produce as against the loss of coastal ocean rise. There is plenty of adequately watered land upon which to make up agricultural short-falls, and new opportunities will arise due to shifiting rain patterns. Loss of oceanfront, however, is far more problematic, especially in nations like Bangladesh. As an economic matter, the cost of producing and shipping food stuffs to drought stricken lands is a relatively short term problem. Once we can identify the locations of the areas that would become permanent drought areas, nations can adapt through population movement and redevelopment of appropriate land use.
Keep in mind that over 80 percent of all people live near coast lines. Moving a large proportion of that 80 percent is much more expensive and destructive than moving a part of the other 20 percent. David Schnare On Tue, Apr 21, 2009 at 8:54 AM, Alan Robock <[email protected]>wrote: > > Dear Ken, > > If Mt. Pinatubo is the poster child, then this poster will contain > drought in large parts of the world. You can see the figures in the > Trenberth and Dai (2007) GRL paper. And don't forget, the effects of > Pinatubo only lasted for a year. A 1-year climate anomaly will not be > that devastating, as food reserves and trade can compensate for > agricultural shortfalls. But a permanent aerosol cloud will make these > effects last for decades. So your poster, using Pinatubo as an example, > argues against geoengineering with stratospheric aerosols. > > The ozone depletion from Pinatubo tells the same story, but I have not > seen a study of how large the effects of that much enhanced UV would be > on the ecosystem and humans. > > I agree that the acid deposition would not seem to be a serious problem, > as we showed in our paper now under review at JGR. > > Alan > > Alan Robock, Professor II > Director, Meteorology Undergraduate Program > Associate Director, Center for Environmental Prediction > Department of Environmental Sciences Phone: +1-732-932-9800 x6222 > Rutgers University Fax: +1-732-932-8644 > 14 College Farm Road E-mail: [email protected] > New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock > > > On Tue, 21 Apr 2009, Ken Caldeira wrote: > > > 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 > >> > >> > >> > >>> > >> > > > > > > > > > > > -- David W. 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