Allen quotes suggested that he thinks lack of deployment technology is an important barrier.
If the question is about starting a slow ramp up of radiative forcing using sulfates-say a ramp that cuts the rate of growth of RF in half)-then I think most important barriers are scientific and social (insufficient knowledge of risks, no legitimate governance regime). The difference matters because research should address the gaps. You are certainly right that we do not have all the technology ready right now to offset a CO2 doubling with certainty about radiative forcing and lifetime. I have trouble understanding how that is relevant. Suddenly turning on a 2XCO2 offset would cause a rapid and likely dangerous cooling. Put simply, it would be nuts. I agree with your statement. It's not clear to me if you actually disagreed with my earlier claim which was more qualified that this straw dog. No one is claiming we are at TRL 8. David From: [email protected] [mailto:[email protected]] On Behalf Of Mark Massmann Sent: Friday, September 13, 2013 7:32 AM To: [email protected] Cc: Alan Robock; [email protected] Subject: [geo] Re: Washington Post story quoting Robock: "No technology exists to do solar radiation management" Dr. Keith and Dr. Caldiera- I think Dr. Robock is right here. From an engineering standpoint, claiming the technology already exists for sulfate aerosols is not a true statement at this stage and could be easily misinterpreted. In my experience with the aerospace field, which uses standardized engineering practices that geo-engineering methods would likely need to follow, this claim would mean: a) the hardware for the injection system has been developed and qualified b) the proper method for injecting sulfates has been determined (stratospheric insertion that is spread properly) c) the natural mechanisms for forming the right particle size have been confirmed d) the expected increase in albedo has been achieved e) the expected residence time of the injection has been met, and f) the method has been proven to be effective over a large enough area (and low enough latitude) to block enough solar radiation (I believe that's 1.9 Petawatts to offset a doubling of pre-industrial CO2) That's a challenging list of unknowns. So my point is, most people will interpret the claim "the technology exists" to include many or most of the things on that list, and may also assume we should be ready to start deploying soon (say a matter of months, vs reality being a matter of years). Maybe the right claim to make might be something like "Stratospheric sulfate injection can be developed using existing technology, and though there are a number of unknowns we would need to address, we believe this approach should be relatively straightforward". Or whatever.... Please let me know your thoughts on this- Mark -- 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]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[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.
