Oliver My views are the reverse of what you suggest. I am well aware that modelling SRM aerosol dynamics and SRM consequences for the atmosphere is at a very early phase of development, as Ferraro demonstrates. It's therefore all the more important that we research these areas, in order to identify areas of concern within our science and engineering. Skipping such complexity from models routinely is, I would argue, a bad habit that has been collectively adopted.
I'm using we/us as a lazy colloquialism for list members, geoengineering researchers and people who are active in the field. The geoclique, as I've heard it disparagingly referred to. I doesn't suggest a commonality of purpose. To rehash an old joke: if you get 3 geoengineers together, they'll give you 10 different opinions on geoengineering. A On 6 Jan 2015 11:17, "olivermorton" <[email protected]> wrote: > Andrew > > Two points on your response to Ken > > One is that you seem to equate including more processes in the model with > making the model "robust". My experience talking to modellers is that this > is not the case. You also seem to accept that the increased detail will > necessarily be reliable. It is quite possible for increased detail to be > spurious. > > The second is that the way you use "we" suggests that all involved are > embarked on a single project. I don't think that is the case (though I do > think everyone wants better informed and less misled discussions of the > potential uses and effects of geoengineering) > > Yours ever and HNY > > o > > On Tuesday, 6 January 2015 08:27:46 UTC, andrewjlockley wrote: >> >> Ken >> >> Modelling doesn't exist in a political vacuum, and the nuances of >> modellers' work are often missed by those interpreting it. >> >> We can see from materials posted to this list how frequently those >> misinterpretations occur, even among professional scientists external to >> the field. A case in point is the article I posted with strong personal >> criticism a couple of days back, which has now been widely syndicated. Such >> bodged pieces often become highly influential. >> >> Two arguments are frequently cited by critics, usually erroneously. The >> first is, of course, that SRM acts as a get-out-of-jail free card. Linked >> to this, is a belief that we could (or should) restore a pre-industrial >> climate at the flick of a switch. This naturally triggers anxiety that SRM >> is poorly understood, and will have severely negative consequences on a >> large geographic scale. The more robust the modelling process, the less >> risk there is of such unanticipated and undesirable consequences. We need >> to both address this argument, and be seen to do so. >> >> The second is the winners-and-losers point: that we would carelessly or >> recklessly impair climate for a few to benefit the many. You may well be >> right that global climate is well replicated by simple SRM approximations >> in models. However, important detail is often lost, as Ferraro shows. Even >> if modellers are not directly attempting to model such detail, their work >> can often be read as if these intricacies are present. Handling the winners >> and losers argument requires direct effort to better understand the >> processes involved. It also requires efforts to ensure that modelling work >> is protected from misinterpretation of fact and misunderstanding of purpose. >> >> Finally, the detail that motivates further and more specific research of >> critical regional impacts and general earth-system side-effects needs to be >> present to trigger such curiosity. Local changes in sea level, temperature >> and precipitation are the stuff policies are made of and by. The risk of >> unintended earth system consequences at large scale are similarly policy >> relevant. We need to go looking for problems, in order to find, understand >> and solve them. >> >> Whilst my caution is specifically aimed at addressing the concerns of >> people outside the field, there is also an internal audience to think of. >> None of us are perfect in our interpretation and recall, and only a handful >> of people are truly cogniscent of all the modelling work that's produced. >> >> My view is that we should be extremely careful of routinely using models >> and modelling techniques with such willful oversimplifications as turning >> down the sun. Caution is particularly important where these convenient >> shortcuts become, for the reasons you describe, a mainstay of modelling >> results. >> >> What percentage of published CE model results have such an assumption? My >> fear is that it's very high. >> >> A >> On 6 Jan 2015 02:22, "Ken Caldeira" <[email protected]> wrote: >> >>> Andrew, >>> >>> Poorly supported sweeping statements are rarely useful. Tools that are >>> good for one purpose and may not be good for other purposes. >>> >>> The utility of a "solar dimming" approach for simulating solar >>> geoengineering depends on what your purpose is. If you are concerned with >>> dynamics of the stratosphere and upper troposphere, then solar dimming will >>> not suffice. >>> >>> However, dimming sunlight produces a surface climate that is broadly >>> similar to that obtained with a uniform aerosol layer, so if your concern >>> is broad features about climate near Earth's surface, solar dimming may >>> suffice. See attached paper: >>> >>> >>> - Kalidindi, S., G. Bala, A. Modak, and K. Caldeira, 2014: Modeling >>> of solar radiation management: a comparison of simulations using reduced >>> solar constant and stratospheric sulphate aerosols. >>> >>> <http://dge.stanford.edu/labs/caldeiralab/Caldeira_research/Kalidindi_RadMgmnt.html> >>> *Clim Dyn*, 1–17, doi:10.1007/s00382-014-2240-3. >>> >>> >>> Below are a few figures illustrating the similarity. Note that there is >>> random variability between simulations even if they have the same forcing. >>> >>> Solar dimming experiments are useful because they easy to implement and >>> there is a minimum of additional assumptions (i.e., the only assumption is >>> a single scalar, and no assumptions need to be made about particle sizes, >>> distributions, etc). When simplicity, clarity, and ease of implementation >>> is a virtue (as with the G1 simulations of GeoMIP) solar dimming can be a >>> very useful model configuration. >>> >>> Best, >>> >>> Ken >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> >>> _______________ >>> Ken Caldeira >>> >>> Carnegie Institution for Science >>> Dept of Global Ecology >>> 260 Panama Street, Stanford, CA 94305 USA >>> +1 650 704 7212 [email protected] >>> http://dge.stanford.edu/labs/caldeiralab >>> https://twitter.com/KenCaldeira >>> >>> My assistant is Dawn Ross <[email protected]>, with access to >>> incoming emails. >>> >>> >>> >>> On Mon, Jan 5, 2015 at 5:36 PM, Andrew Lockley <[email protected]> >>> wrote: >>> >>>> Poster's note : another study showing solar dimming is a risky >>>> approximation to make in SRM models >>>> >>>> http://onlinelibrary.wiley.com/doi/10.1002/2014JD022734/abstract >>>> >>>> Stratospheric dynamics and midlatitude jets under geoengineering with >>>> space mirrors, and sulfate and titania aerosols >>>> >>>> A. J. Ferraro, A. J. Charlton-Perez and E. J. Highwood >>>> DOI: 10.1002/2014JD022734 >>>> >>>> Journal of Geophysical Research: Atmospheres >>>> >>>> Abstract >>>> >>>> The impact on the dynamics of the stratosphere of three approaches to >>>> geoengineering by Solar Radiation Management is investigated using >>>> idealized simulations of a global climate model. The approaches are >>>> geoengineering with sulfate aerosols, titania aerosols and reduction in >>>> total solar irradiance (representing mirrors placed in space). If it were >>>> possible to use stratospheric aerosols to counterbalance the surface >>>> warming produced by a quadrupling of atmospheric carbon dioxide >>>> concentrations, tropical lower stratospheric radiative heating would drive >>>> a thermal-wind response which would intensify the stratospheric polar >>>> vortices. In the Northern Hemisphere this intensification results in strong >>>> dynamical cooling of the polar stratosphere. Northern Hemisphere >>>> stratospheric sudden warming events become rare (1 or 2 in 65 years for >>>> sulfate and titania respectively). The intensification of the polar >>>> vortices results in a poleward shift of the tropospheric midlatitude jets >>>> in winter. The aerosol radiative heating enhances the tropical upwelling in >>>> the lower stratosphere, influencing the strength of the Brewer-Dobson >>>> Circulation. In contrast, solar dimming does not produce heating of the >>>> tropical lower stratosphere so there is little intensification of the polar >>>> vortex and no enhanced tropical upwelling. The dynamical response to >>>> titania aerosol is qualitatively similar to the response to sulfate. >>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "geoengineering" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at http://groups.google.com/group/geoengineering. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> > *This e-mail may contain confidential material. If you are not an intended > recipient, please notify the sender and delete all copies. It may also > contain personal views which are not the views of The Economist Group. We > may monitor e-mail to and from our network.* > > *Sent by a member of The Economist Group. 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