Dear Tom: I agree 350ppm(V) is likely an impossible mark, but stopping at a concentration equivalent to a two degree limit this century is not.
See, for example, the Global Environmental Assessment (GEA) published last year by IIASA. It defines some 41 pathways that would work to stay below 2 degrees. Further, these pathways are compatible with achieving three other goals:achieving global energy security, assuring universal access to clean cooking fuels and electricity for the poor, and avoiding pollution and other environmental damage from the use of energy. The Global Energy Assessment is available for free at GlobalEnvironmentalAssessment.org. It is in hard copy from Cambridge University Press. The best, Bill Fulkerson 1-865-680-0937 wf...@utk.edu Institute for a Secure and Sustainable Environment The University of Tennessee On 10/30/13 3:19 AM, "Tom Wigley" <wig...@ucar.edu> wrote: >Dear all, > >Dropping CO2 concentrations to 350 ppm in 50 years is impossible >unless we can find a cheap way to suck a whole lot of CO2 out of the >atmosphere. > >Some simple calculations are attached. > >Tom. > >++++++++++++++++++++++++++++++++++++= > >On 10/29/2013 2:18 PM, Ronal W. Larson wrote: >> List and Brian: >> >> I just noted a mis-statement. See below. >> >> >> On Oct 29, 2013, at 1:28 PM, Ronal W. Larson <rongretlar...@comcast.net >> <mailto:rongretlar...@comcast.net>> wrote: >> >>> Brian (cc list) This to respond to your three inserts in my >>> yesterday¹s response to you >>> >>> BC1: */But that's not very good. Warming-induced feedback loops like >>> methane deposits are already very scary. I don't say CO2 levels are >>> irreversible; my point is about warming from all causes, and you need >>> methods of cooling that are much quicker than 50 years. /* >>>> >>> *[RWL1: Brian¹s ³that² refers to my just previous statement (see >>> below) that we could drop to 350 ppm in 50 years. Brian is NOT >>> arguing for SRM here, although it may seem so. He is arguing for >>> increased latent heat transfer - an approach that seems questionable >>> at best - given the strong warming potential of increased atmospheric >>> carbon.* >> >> RWL: The last word was supposed to be ³moisture² - NOT ³carbon². >> Apologies. I am too used to following ³atmospheric² with ³carbon². >> >> Ron >> >> <snip remainder> >> >> -- >> 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 post to this group, send email to geoengineering@googlegroups.com. >> Visit this group at http://groups.google.com/group/geoengineering. >> 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 geoengineering+unsubscr...@googlegroups.com. >To post to this group, send email to geoengineering@googlegroups.com. >Visit this group at http://groups.google.com/group/geoengineering. >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 geoengineering+unsubscr...@googlegroups.com. To post to this group, send email to geoengineering@googlegroups.com. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.
