Folks, Upon further reflection, I would like to retract my statement about "false statement". Sometimes my fingers hit the keyboard before my brain engages. I apologize for saying a statement was false, when I was in error for misinterpreting the statement.
The IPCC WG1 SPM does not say "If SRM were* phased out* for any reason, ...", it says "If SRM were *terminated *for any reason, ...". It is apparent from context that the authors were referring to an abrupt termination of SRM. Sometimes, in an effort to be concise, some clarity of expression can be lost. It would have been good if the word "suddenly" were in the sentence explicitly, but I think we can assume it is there implicitly. If the authors had intended to refer to a gradual phase out, they likely would have used an expression like "phase out". I have full confidence in the IPCC process, the quality of the participating scientists, and the quality of the reports produced. Regards, Ken _______________ 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 https://twitter.com/KenCaldeira On Fri, Sep 27, 2013 at 2:23 PM, Ken Caldeira <[email protected] > wrote: > They left out an important word ("suddenly"), leaving them with a false > sentence. > > Methods that aim to deliberately alter the climate system to counter > climate change, termed geoengineering, have been proposed. Limited evidence > precludes a comprehensive quantitative assessment of both Solar Radiation > Management (SRM) and Carbon Dioxide Removal (CDR) and their impact on the > climate system. CDR methods have biogeochemical and technological > limitations to their potential on a global scale. There is insufficient > knowledge to quantify how much CO2 emissions could be partially offset by > CDR on a century timescale. Modelling indicates that SRM methods, if > realizable, have the potential to substantially offset a global temperature > rise, but they would also modify the global water cycle, and would not > reduce ocean acidification. If SRM were terminated *suddenly *for any > reason, there is high confidence that global surface temperatures would > rise very rapidly to values consistent with the greenhouse gas forcing. CDR > and SRM methods carry side effects and long-term consequences on a global > scale. {6.5, 7.7} (p. 21) > > Unfortunately, that sentence is false as written. If SRM were terminated > with a slow phase out, surface temperatures would not rise very rapidly. > > > _______________ > 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 > https://twitter.com/KenCaldeira > > > > On Fri, Sep 27, 2013 at 1:57 PM, Josh Horton <[email protected]>wrote: > >> It's finally out and here's what it says about geoengineering: >> >> >> http://www.climatechange2013.org/images/uploads/WGIAR5-SPM_Approved27Sep2013.pdf >> >> Methods that aim to deliberately alter the climate system to counter >> climate change, termed geoengineering, have been proposed. Limited evidence >> precludes a comprehensive quantitative assessment of both Solar Radiation >> Management (SRM) and Carbon Dioxide Removal (CDR) and their impact on the >> climate system. CDR methods have biogeochemical and technological >> limitations to their potential on a global scale. There is insufficient >> knowledge to quantify how much CO2 emissions could be partially offset >> by CDR on a century timescale. Modelling indicates that SRM methods, if >> realizable, have the potential to substantially offset a global temperature >> rise, but they would also modify the global water cycle, and would not >> reduce ocean acidification. If SRM were terminated for any reason, there is >> high >> confidence that global surface temperatures would rise very rapidly to >> values consistent with the greenhouse gas forcing. CDR and SRM methods >> carry side effects and long-term consequences on a global scale. {6.5, 7.7} >> (p. 21) >> Not quite what the Guardian was reporting last week ... >> >> Josh >> >> >> -- >> 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. >> > > -- 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.
