Hi John--I wholeheartedly agree that a gradual implementation could be done. It seems to me, however, in many of the discussions, the application is being talked about as an emergency application that could be done much more rapidly than CO2 mitigation rather than as a gradual application. It is those proposed cases that prompted my comment.
Best, Mike On 5/22/13 1:44 AM, "John Latham" <[email protected]> wrote: > Sorry if I'm missing a point, Mike, but - in principle - the transition > to full SRM deployment in the case of Marine Cloud Brightening > could be made at a selected rate and modified in a controllable > manner by adjusting the sea-water spray rate. Additional > flexibility is provided by varying the choices of the locations at which > sprayiing occurs. The same principles could be applied to sub-global MCB > geo-engineering, in the cases of coral reef protection and > weakening of hurricanes, via propitiously chosen surface water > cooling. > All Best, John. > > > John Latham > Address: P.O. Box 3000,MMM,NCAR,Boulder,CO 80307-3000 > Email: [email protected] or [email protected] > Tel: (US-Work) 303-497-8182 or (US-Home) 303-444-2429 > or (US-Cell) 303-882-0724 or (UK) 01928-730-002 > http://www.mmm.ucar.edu/people/latham > ________________________________________ > From: [email protected] [[email protected]] on > behalf of Mike MacCracken [[email protected]] > Sent: 22 May 2013 03:17 > To: Andrew Lockley; Geoengineering > Subject: Re: [geo] The importance of response times for various climate > strategies - Springer > > I continue to wonder how one can be so concerned about the warming that would > occur at a supposed end of SRM and not be worried about the rapid onset of SRM > if used in an emergency manner (not to mention that by the time of the > emergency it may be too late to reverse (e.g., think about Greenland melting > rate, could it be reversed?). As climate warms/changes, there is always some > adaptation going on, so the thought of suddenly taking the global average temp > down a degree C would likely lead to quite large disruptions and dislocations, > just as would coming out of such a cooling. The disruption of going into SRM > can be smoothed, and so could an exit (if we assume we have as much sense as > needed to get agreement to start SRM), just as going in one could have a > sudden change likely as disruptive as coming out if not managed well. So, why > all the focus on the back end problem, without a similar concern at start-up? > > Mike MacCracken > > > On 5/21/13 8:37 PM, "Andrew Lockley" <[email protected]> wrote: > > http://link.springer.com/article/10.1007/s10584-013-0769-5 > > If climate action becomes urgent: the importance of response times for various > climate strategies > > Detlef P. van Vuuren, Elke Stehfest > > Abstract > > Most deliberations on climate policy are based on a mitigation response that > assumes a gradually increasing reduction over time. However, situations may > occur where a more urgent response is needed. A key question for climate > policy in general, but even more in the case a rapid response is needed, is: > what are the characteristic response times of the response options, such as > rapid mitigation or solar radiation management (SRM)? This paper explores this > issue, which has not received a lot of attention yet, by looking into the role > of both societal and physical response times. For mitigation, technological > and economic inertia clearly limit reduction rates with considerable > uncertainty corresponding to political inertia and societies¹ ability to > organize rapid mitigation action at what costs. The paper looks into a rapid > emission reductions of 46 % annually. Reduction rates at the top end of this > range (up to 6 %) could effectively reduce climate change, but only with a > noticeable delay. Temperatures could be above those in the year of policy > introduction for more than 70 years, with unknown consequences of overshoot. A > strategy based on SRM is shown to have much shorter response times (up to > decades), but introduces an important element of risk, such as ocean > acidification and the risk of extreme temperature shifts in case action is > halted. Above all, the paper highlights the role of response times in > designing effective policy strategies implying that a better understanding of > these crucial factors is required. > > This article is part of a special issue on "Geoengineering Research and its > Limitations" edited by Robert Wood, Stephen Gardiner, and Lauren > Hartzell-Nichols. > > -- > 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?hl=en. > For more options, visit https://groups.google.com/groups/opt_out. > > -- 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]. 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