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