Very good discussion. I'm trying to get a balance of pros (benefits B1-B7) and cons (specific fears S1-S21). What I'd like out of our discussion is some kind of risk assessment for the possible downside of a weaker monsoon, as this is considered the biggest risk in the regional effects (S1). And we could make this reasonably pessimistic, to be on the safe side - i.e. be cautious with the application of geoengineering. On the other hand, we might be able to reduce this risk, e.g. by neutralising sulphate aerosol; if there's a good chance of this working, then we can factor that into the calculation. Or the risk might be offset by a benefit in that region, e.g. improved summer water supply from Himalayan glaciers?
So, what kind of impact would a weaker monsoon (ISM) have on India? What is the probability of stratospheric aerosols deployed in the Arctic would produce a weaker monsoon? Can this risk be significantly countered? Can it be significantly offset? Note that the risk on benefit side might be measured in terms of a risk, without geoengineering, of millions or even billions of lives being lost (especially if massive methane release adds several degrees of global warming, B4). Alternatively we could measure in GDP lost - current global GDP (aka GWP) is about $60 trillion I believe. Cheers, John ----- Original Message ----- From: "Alvia Gaskill" <[email protected]> To: <[email protected]>; <[email protected]> Cc: <[email protected]>; "Andrew Lockley" <[email protected]>; <[email protected]>; <[email protected]>; <[email protected]>; <[email protected]>; <[email protected]>; <[email protected]> Sent: Saturday, May 09, 2009 4:50 PM Subject: Re: [geo] Re: Balancing the pros and cons of geoengineering > Stephen makes a good point that leads to a more general one. If there are > precipitation reductions associated with sunlight blocking schemes, > consideration should also be given to mitigating these, analogous to the > medications given to patients with Type II diabetes to combat the side > effects of the primary drug. > > This is an oversimplification, but the way summer monsoons work is that in > the summer the land gets warmer than the ocean faster, creating a low > pressure area and this causes on shore flow as air moves from high to low > presssure. For some reason, Laki caused this to be muted. There were no > aerosols from Laki over India and it has been suggested there was a > teleconnected response (see the paper Stephen attached) although in paleo > climate the authors say the effects were direct, but don't give specifics. > In the case of Pinatubo, both the land and sea were cooled by the aerosol > and the land simply didn't heat up fast enough to generate the on shore > flow. > > If the Arctic only aerosol geoengineering does cause a reduction in the > ISM (Indian Summer Monsoon as there are other monsoons that affect India, > but this is the most important one), use of the cloud whitening to restore > at least some of the temperature differential should be considered. > Likewise, in a global aerosol scheme, with a global aerosol spread similar > to that of Pinatubo, the cloud whitening could also be used to create a > temperature differential, but at some point it becomes a race to the > bottom, with the land temperature simply too cool to initiate the low > pressure area. In this case, reducing the depth of the aerosol layer over > the land may be the most effective way to restore the dynamics. > > I previously suggested using ammonia released from either planes or > balloons to react with the sulfate aerosol and drop them out as ammonium > sulfate. This idea as well as Stephen's could be applied to other > locations such as the Amazon, Eastern China and Africa where models > indicate unacceptable reductions in precipitation are a result of either > aerosol geoengineering or global warming. Of course, the ammonia wouldn't > be of any value in a global warming/no aerosol scenario. > > I said in one the earliest papers I wrote on geoengineering that > eventually we were going to have to learn how to manipulate the climate to > our advantage. That includes both gross scale and fine tuning. > > In a related issue, last year I posted a link from a group in the UK that > was carrying out some 130 different models of aerosol geoengineering. It > was a volunteer effort among universities. If they have done even a > fraction of the modeling, this work should be taken into account in > designing new studies such as Rutgers is proposing. Anyone have an > update? > > You may recall also that we spent some time last year discussing the > significance of the "little brown blotches" in absolute terms and now Ken > also raises the issue of their resolution. > > http://en.wikipedia.org/wiki/Monsoon > > Monsoons are caused by the larger amplitude of the seasonal cycle of land > temperature compared to that of nearby oceans. This differential warming > happens because heat in the ocean is mixed vertically through a "mixed > layer" that may be fifty meters deep, through the action of wind and > buoyancy-generated turbulence, whereas the land surface conducts heat > slowly, with the seasonal signal penetrating perhaps a meter or so. > Additionally, the specific heat capacity of liquid water is significantly > higher than that of most materials that make up land. Together, these > factors mean that the heat capacity of the layer participating in the > seasonal cycle is much larger over the oceans than over land, with the > consequence that the air over the land warms faster and reaches a higher > temperature than the air over the ocean.[11] Heating of the air over the > land reduces the air's density, creating an area of low pressure. This > produces a wind blowing toward the land, bringing moist near-surface air > from over the ocean. Rainfall is caused by the moist ocean air being > lifted upwards by mountains, surface heating, convergence at the surface, > divergence aloft, or from storm-produced outflows at the surface. However > the lifting occurs, the air cools due to expansion, which in turn produces > condensation. > > In winter, the land cools off quickly, but the ocean retains heat longer. > The cold air over the land creates a high pressure area which produces a > breeze from land to ocean.[11] Monsoons are similar to sea and land > breezes, a term usually referring to the localized, diurnal (daily) cycle > of circulation near coastlines, but they are much larger in scale, > stronger and seasonal.[12] > > > > ----- Original Message ----- > From: "Stephen Salter" <[email protected]> > To: <[email protected]> > Cc: <[email protected]>; "Andrew Lockley" > <[email protected]>; <[email protected]>; <[email protected]>; > <[email protected]>; <[email protected]>; > <[email protected]>; <[email protected]> > Sent: Saturday, May 09, 2009 6:43 AM > Subject: [geo] Re: Balancing the pros and cons of geoengineering > > >> Hi All >> >> The attached paper by Zickfeld et al shows, in figure 2, what might >> happen to the Indian Monsoon if we do nothing. Cooling the sea relative >> to the land should move things in the opposite direction. >> >> Stephen >> >> Emeritus Professor of Engineering Design >> School of Engineering and Electronics >> University of Edinburgh >> Mayfield Road >> Edinburgh EH9 3JL >> Scotland >> tel +44 131 650 5704 >> fax +44 131 650 5702 >> Mobile 07795 203 195 >> [email protected] >> http://www.see.ed.ac.uk/~shs >> >> >> >> Alan Robock wrote: >>> Dear Ken, >>> >>> I agree. We need several models to do the same experiment so we can see >>> how robust the ModelE results are. That is why we have proposed to the >>> IPCC modeling groups to all do the same experiments so we can compare >>> results. Nevertheless, observations after large volcanic eruptions, >>> including 1783 Laki and 1991 Pinatubo, show exactly the same precip >>> reductions as our calculations. >>> >>> Even if precip in the summer monsoon region goes down, how important is >>> it for food production? It will be countered by increased CO2 and >>> increased diffuse solar radiation, both of which should make plants grow >>> more. We need people studying impacts of climate change on agriculture >>> to take our scenarios and analyze them. >>> >>> Alan >>> >>> Alan Robock, Professor II >>> Director, Meteorology Undergraduate Program >>> Associate Director, Center for Environmental Prediction >>> Department of Environmental Sciences Phone: +1-732-932-9800 x6222 >>> Rutgers University Fax: +1-732-932-8644 >>> 14 College Farm Road E-mail: [email protected] >>> New Brunswick, NJ 08901-8551 USA http://envsci.rutgers.edu/~robock >>> >>> >>> >>> Ken Caldeira wrote: >>> >>>> A few questions re claims about monsoons: >>>> >>>> 1. How well is the monsoon represented in the model's base state? Is >>>> this a model whose predictions about the monsoon are to be trusted? >>>> >>>> 2. Since the believability of climate model results for any small >>>> region based on one model simulation is low, for some reasonably >>>> defined global metrics (e.g., rms error in temperature and precip, >>>> averaged over land surface, cf. Caldeira and Wood 2008) is the amount >>>> of mean climate change reduced by reasonable aerosol forcing? (I >>>> conjecture yes.) >>>> >>>> Alan is interpreting as significant his little brown blotches in the >>>> right side of Fig 7 in a model with 4 x 5 degree resolution (see >>>> attachment). >>>> >>>> How does the GISS ModelE do in the monsoon region? If you look at Fig >>>> 9 of Jiandong et al (attached), at least in cloud radiative forcing, >>>> GISS ModelE is one of the worst IPCC AR4 models in the monsoon region. >>>> >>>> So, while Alan may ultimately be proven right, it is a little >>>> premature to be implying that we know based on Alan's simulations how >>>> these aerosol schemes will affect the Indian monsoon. >>>> >>>> If you look at Caldeira and Wood (2008), we find that idealized Arctic >>>> solar reduction plus CO2, on average precipitation is increased >>>> relative to the 1xCO2 world. >>>> >>>> >>>> ___________________________________________________ >>>> Ken Caldeira >>>> >>>> Carnegie Institution Dept of Global Ecology >>>> 260 Panama Street, Stanford, CA 94305 USA >>>> >>>> [email protected] <mailto:[email protected]>; [email protected] >>>> <mailto:[email protected]> >>>> http://dge.stanford.edu/DGE/CIWDGE/labs/caldeiralab >>>> +1 650 704 7212; fax: +1 650 462 5968 >>>> >>>> >>>> >>>> >>> >>> > >>> >>> >> >> >> -- >> >> >> >> >> The University of Edinburgh is a charitable body, registered in >> Scotland, with registration number SC005336. >> >> >> >> >> > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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