A number of recent high caliber dicussions of Solar Radiation Management research, governance and deployment have focused exclusively on stratospheric aerosol dispersal. It may be useful for any who are thinking about solar radiation management to include tropospheric techniques, particularly the (relatively) mature proposed method of SRM via Marine Cloud Brightening (Latham-Salter technique) in policy and research considerations.
There are important reasons to include marine cloud brightening as a component of any SRM research program. 1. *The global cooling potential may be similar to stratospheric aerosols *. More work is needed, but early studies by Latham et. al. and more recent studies from Rasch et. al. and Caldeira et.al. indicate potential cooling/ CO2 offset effects and ice retention that compare favorable to forecasts for stratospheric aerosols. 2. *The primary risk profile is different from stratospheric aerosols. *The techniques have differing precipitation effects and atmospheric chemistry. 3. *The deployment profile is different. *Marine cloud brightening supports local /regional testing and deployment possibilities vs inherently global distribution in the stratosphere. 4. *The duration of the effect is different. *Marine cloud brightening has a 2-3 day dissipation of the effect vs months or years for stratospheric aerosols. 5. *The research profile is different. *Cloud-aerosol dynamics are an important gap in atmospheric science and cloud models, and aspects of early research in marine cloud brightening are similar or identical to studies of these general questions. In addition, it is possible to study engineered effects on cohorts of clouds or regions of climate in a way that is difficult or impossible to do in the stratosphere. 6. *Policy and public perception are different.* Local or regional cloud-aerosol research is likely to have fewer international regulatory considerations and a more benign public perception. 7. *Experience and knowledge transfer*. There is likely to be very useful knowledge sharing across teams working on scientific, modeling and technical issues for both the stratosphere and the troposphere which should lend to more rigor, transparency and better informed regulation and monitoring of each. 8. *Inadvertent tropospheric/cloud brightening effects are already occurring*, and require additional research. Large scale reduction in emissions may have warming effects in which albedo offset alternatives may be desirable. 9. *The optimum approach may be to use multiple techniques*. The risk-benefit profiles of the two most mature methods of solar radiation management, stratospheric aerosol dispersal and marine cloud brightening, suggest the possibility that the use of multiple sources of radiative forcing may reduce overall side-effects. A large collaborative effort is underway that includes researchers at Manchester University, Leeds University, the University of Washington, the University of Edinburgh, NCAR, PNNL, PARC, Purdue University and elsewhere, to continue to analyze cloud aerosol effects in marine clouds and their impact on climate. This research will advance both understanding of currently poorly understood dynamics in the climate system (clouds and aerosols, boundary layer effects etc) and to advance knowledge relevant to marine cloud brightening as a form of geoengieering. Kelly Wanser Silver Lining Project -- -- Kelly Wanser CEO eCert, Inc. One Market Street, Suite 3500 San Francisco, California 94105 p. +1 (415) 734-6790 f. +1 (415) 651-8932 e. [email protected] eCert - Trust the Message http://www.ecertsystems.com -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en.
