Personally, I look forward to comments on our paper that has just been posted for discussion and think the idea of wider discussion of draft papers is a good idea (in addition to the normal review set of comments, which is also taking place).
The key point of the paper is start determining if there are ways in which application of SRM can be engineered to reduce its problematic aspects while still using the approach to address the most important impacts being caused by climate change, in this paper¹s case, high latitude climate change, and perhaps do so in the nearer rather than the long term. Admittedly, calculations are idealized and implementation might well be challenging, but the question is whether we can optimize not just how the sulfate layer might be created or clouds brightened, but also about the distribution of the intervention and the objectives being pursued to find potentially more practical and workable approaches. So, yes, comments would be welcomed. Mike MacCracken On 7/26/12 6:27 AM, "Ken Caldeira" <[email protected]> wrote: > MacCracken, M. C., Shin, H.-J., Caldeira, K., and Ban-Weiss, G. A.: Climate > response to imposed solar radiation reductions in high latitudes, Earth Syst. > Dynam. Discuss., 3, 715-757, doi:10.5194/esdd-3-715-2012, 2012. > > Folks, > > I am not a big fan of these discussion journals, but we have nevertheless > submitted a manuscript to Earth System Dynamics Discussions. You are invited > to comment on this paper at > http://www.earth-syst-dynam-discuss.net/3/715/2012/esdd-3-715-2012.html > > The abstract is repeated below. > > Best, > > Ken > > -------------------------------------- > > Earth Syst. Dynam. Discuss., 3, 715-757, 2012 > www.earth-syst-dynam-discuss.net/3/715/2012/ > <http://www.earth-syst-dynam-discuss.net/3/715/2012/> > doi:10.5194/esdd-3-715-2012 > © Author(s) 2012. This work is distributed > under the Creative Commons Attribution 3.0 License. > > Climate response to imposed solar radiation reductions in high latitudes > > M. C. MacCracken1, H.-J. Shin2,3, K. Caldeira2, and G. A. Ban-Weiss2,4 > 1Climate Institute, 900 17th St. NW, Suite 700, Washington, DC 20006, USA > 2Carnegie Institution for Science, Deptartment of Global Ecology, 260 Panama > Street, Stanford, CA 94305, USA > 3Korea Institute of Atmospheric Prediction Systems, Systems Division/Model > Validation Team 35 Boramae-ro 5-gil, Dongjak-gu, Seoul, 156-849, South Korea > 4Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, Berkeley, CA 94720, > USA > > Abstract. Increasing concentrations of greenhouse gases are the primary > contributor to the 0.8 °C increase in the global average temperature since the > late 19th century, shortening cold seasons and lengthening warm seasons. The > warming is amplified in polar regions, causing retreat of sea ice, snow cover, > permafrost, mountain glaciers, and ice sheets, while also modifying > mid-latitude weather, amplifying global sea level rise, and initiating > high-latitude carbon feedbacks. Model simulations in which we reduced solar > insolation over high latitudes not only cooled those regions, but also drew > energy from lower latitudes, exerting a cooling influence over much of the > hemisphere in which the reduction was imposed. Our simulations, which used the > National Center for Atmospheric Research's CAM3.1 atmospheric model coupled to > a slab ocean, indicated that, on a normalized basis, high-latitude reductions > in absorbed solar radiation have a significantly larger cooling influence than > equivalent solar reductions spread evenly over the Earth. This amplified > influence occurred because high-latitude surface cooling preferentially > increased sea ice fraction and, therefore, surface albedo, leading to a larger > deficit in the radiation budget at the top of the atmosphere than from an > equivalent global reduction in solar radiation. Reductions in incoming solar > radiation in one polar region (either north or south) resulted in increased > poleward energy transport during that hemisphere's cold season and shifted the > Inter-Tropical Convergence Zone (ITCZ) away from that pole, whereas equivalent > reductions in both polar regions tended to leave the ITCZ approximately in > place. Together, these results suggest that, until emissions reductions are > sufficient to limit the warming influence of greenhouse gas concentrations, > polar reductions in solar radiation, if they can be efficiently and > effectively implemented, might, because of fewer undesirable side effects than > for global solar radiation reductions, be a preferred approach to limiting > both high-latitude and global warming. > > > _______________ > 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 @kencaldeira > > Currently visiting Institute for Advanced Sustainability Studies (IASS) > <http://www.iass-potsdam.de/> > and Potsdam Institute for Climate Impact Research (PIK) > <http://www.pik-potsdam.de/> in Potsdam, Germany. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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