Mike et al., David Kieth let me know (through PM) that his group is trying to incorporate the possible increase of PSCs, due to SSI, into their model. The issues of PSC increases and ozone loss are both closely related to atmospheric sulfur particulates. If SSI is to be used, due to the strong effect of PSCs on surface temperatures and the loss of ozone due to PSCs, has there been any thought on limiting SSI to the equatorial regions (as the Hadley Cell circulation may help limit polar concentrations of SSI (sulfur) particles). If we loose polar ice, and thus increase tundra flooding/methane release, at the cost of lowering the planitary 'average' temperature, have we moved forward or backwards? Best, Michael
On Tuesday, September 3, 2013 1:38:19 PM UTC-7, Mike MacCracken wrote: > Hi Andrew: Agreed. Speculating a bit, if, as Jennifer Francis hypothesis > is right that the jet stream has become wavier as the equator-pole gradient > has been reduced, then one would expect for the jet to be pushed back > toward the more zonal flow of the past, but that certainly needs to be a > question that is researched. Do remember that without doing anything, > global warming will continue to go on essentially unabated. > > Mike > > > On 9/3/13 4:23 PM, "Andrew Lockley" <[email protected]> wrote: > > Speaking as a periodically soaked/parched and frozen/boiled brit, I think > that the effect of polar only SRM on the jet stream would need to be > thoroughly investigated before anyone seriously proposed it. > > A > > On Sep 3, 2013 9:17 PM, "Mike MacCracken" <[email protected]> wrote: > > Hi Bill—That is a good question to look closely at. I would suggest, > without having done the studies, so doing so speculatively, that in that > the complex pattern of geography, land-sea, etc. currently lead to energy > being added now to the atmosphere in an uneven way, and so I am not > convinced having some moderate unevenness would be a problem, etc. Yes, in > detail, the weather would be affected, but the question is whether the > statistics of the weather (i.e., the climate) is altered. But, indeed, > research is needed on this. > > Mike > > > > > On 9/3/13 2:51 PM, "William H. Calvin" <[email protected] < > http://[email protected]> > wrote: > > Re the more detailed model: Both high haze and MCB have a problem, that of > uneven application and its probable consequences. > > Big perturbations in seasonal delivery of moisture to a region result in > drought and/or deluge. Indeed, one states' drought may be another state's > deluge, simply because of a detour in the precip pipeline. What can cause a > detour? > > The current example comes from the land warming twice as fast as the ocean > surface, the excess high pressure systems over land forcing a rearrangement > in flow patterns. *Uneven *external forcing is another way, cooling one > region to create denser air while not doing the same to its neighbors. > Winds rearrange. > > Thus my concern about uneven application of shadows. But shadows have > penumbrias that vary with the length of the shadow. In our eyes, shadows > caused by debris floating around can be seen only if the obstruction is > close to the retina. If the debris is halfway back to the lens, its shadow > will be too fuzzy to register. > > Thus I see *uniform *sunlight reduction as necessary to avoid additional > drought and deluge, and see the most likely way of achieving uniformity to > involve sunscreens that are far above the atmosphere. > > Of course, success in reducing solar input would do nothing for reducing > ocean acidification since dimming will not get rid of the growing excess of > CO2. Air capture of CO2 is the only thing I know that could back us out of > the danger zone for extreme weather and acidification. > > Cheers, > -Bill > > On Monday, September 2, 2013 7:49:54 AM UTC-7, Mike MacCracken wrote: > > A new paper by myself, Ho-Jeong Shin, Ken Caldeira, and George Ban-Weiss > that provides a conceptual look at the notion of polar SRM is available > for > free download at http://www.earth-syst-dynam.net/4/301/2013/ > > The results suggest that a much more detailed model evaluation of this > possible approach to limiting the amplified climate change in high > latitudes > is merited. > > Mike MacCracken > > > -- 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/groups/opt_out.
