this is the allen roebuck point. once deployed the effects of solar radiation management on the climate with a difficult to isolate from the effects of natural variability and indeed from the effects of human induced global warming. it would take it is estimated or guessed at least a decade from full deployment of sulfate aerosol spraying before enough data became available to judge confidently whether these solar filters were working as planned. if allen roebuck is right in this objection i think this fact would drive the data into the heart of the scheme which ice i said -- it would take a decade to generate the data needed to assess the impact of full deployment of sulfate aerosol spray it would take much longer with david's proposal to start slowly and go halfway. with no desire for bull information coming in we will be flying blind for a very long time. so i think the scheme that david reposes is after initially setting the control variables the engineer must obtain feed that from the system before adjusting it