Hi Bala, Agree that we need to better understand the impact of different choices, but I'm not sure why you think it is "precise control" to avoid injection into a single hemisphere? We've known for a long time that doing something like only injecting at 15N would be a bad idea, so hopefully no-one will do that (and if someone did, and diplomacy weren't enough to dissuade them, then some other actor should develop simultaneous capability to inject at 15S; in that sense I don't think a sustained significant deployment at 15N is a remotely plausible scenario as it would require an actor so driven to damage the tropics that they are willing to use military force to block any other actor from deployment).
Here's a hypothesis (broadly similar to the sort phrased by Peter Irvine and David Keith): In any climate model, a symmetric injection (whatever you do in one hemisphere, do the same in the other) sufficient to cool by ~1C (so 2C warming --> 1C, or 2.5 --> 1.5C) will not lead to changes in monsoon precipitation that are detectably outside the range of historical values. That seems eminently testable. I do agree that the sorts of feedback control algorithms we used in GLENS, for example, are purely modeling tools and not representative of the adjustment strategies that would occur in a real deployment (which would likely be more based on updating climate models based on observations and making new projections of different strategies) doug On Sun, Jan 9, 2022 at 1:03 AM Govindasamy Bala <bala....@gmail.com> wrote: > Dear All, > > In this paper that came out last week in Climate Dynamics > <https://doi.org/10.1007/s00382-021-06121-z>, we looked at the changes in > mean precipitation in tropical monsoon regions for sulfate injections at > different latitudes. > > Key message: India could experience persistent droughts if aerosols are > injected at 15 or 30 deg N. The result is interpreted from planetary > energetics and interhemispheric asymmetry in energy balance. > > Many of you may be aware that Ben Kravitz, Doug, Simone and others have > worked on ideas such as controlled injections at several locations > simultaneously to avoid such catastrophes, but I am not sure we can really > have such precise control on the climate system.... > > -- > With Best Wishes, > > ------------------------------------------------------------------- > G. Bala > Professor > Center for Atmospheric and Oceanic Sciences > Indian Institute of Science > Bangalore - 560 012 > India > > Tel: +91 80 2293 3428; +91 80 2293 2505 > Fax: +91 80 2360 0865; +91 80 2293 3425 > Email: gb...@iisc.ac.in; bala....@gmail.com > Google Scholar <https://scholar.google.com/citations?user=eurjQPwAAAAJ> > ------------------------------------------------------------------- > > -- > 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 geoengineering+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/geoengineering/CAD7fhVk1OSANz7esABWgM%2BNFG9P%2BAo57Nuvecx27k9VF_Duvwg%40mail.gmail.com > <https://groups.google.com/d/msgid/geoengineering/CAD7fhVk1OSANz7esABWgM%2BNFG9P%2BAo57Nuvecx27k9VF_Duvwg%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- 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 geoengineering+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/geoengineering/CALaO3y-3r4Ra-Tj0XwFPFvRKn_KY69k29mydy1ZUEqt-iev4rA%40mail.gmail.com.
