Dear Colleagues, Lenton and Vaugn ignored or response to Vogt et al The letter below appears as a discusion comment associated with the Lenton/Vaughan paper.
OWW Dear Prof. Lenton: Thank you for considering our possible geoengineering solution in your paper. I would like to clear up some misconceptions. We consider fertilizing several small areas of the Southern Ocean to nanomolar concentrations of iron. Not one large patch, in order to minimize particle growth and maximize new particle formation [Wingenter et al., 2007]. First it is unfair to compare our regional solution to possibly slowing, or prevent, the Western Antarctic Ice Sheet from melting and raising sea level an additional 6 meters. I believe this is covered fairly well in our reply [attached; Wingenter et al., 2008] to Vogt et al [2008], which appears in the same edition of Atmospheric Environment. Secondly, we feel a 20 % percent increase of DMS will lead to a 10% increase in CCN. This is based on the paper by Ayers et al. [1997]. Unfortunately, Vogt et al., apply two treatments to the hypothetical 20 % increase and arrive at a smaller conversion of DMS to CCN when only one treatment is called for. The mistakes of our UEA colleagues mistake is also discussed in our reply to Vogt et al. Perhaps more importantly is that our original paper describes how to cool the SO region 2 C. Are estimate is not based on a GCM modeling study and contains no feedbacks. They are simply, first order, calculation as described in this paper. Vogt et al. estimate is also done at the same level. Considering the very large uncertainties in this type of an approach, our estimates are actually in agreement. If this geoengineering method is to be tried on a limited basis, we would advocate the much smaller two percent fertilization of an area than an initial 8% area of fertilization suggested by Vogt et al. to attain the a 2 C cooling. However, cooling the Southern Ocean region 2 C is perhaps 1.5 C to much and would likely cause changes to the general atmospheric and ocean circulation. Perhaps fertilizing just some regions near the coast would accomplish the necessary ice sheet stabilization we seek. The idea is only in its infancy and we hope more in depth study will improve our concept. Sincerely, Oliver W. Wingenter, Ph.D. Assoc. Prof. of Atmospheric Chemistry Research Scientist, Geophysical Research Center New Mexico Institute of Mining and Technology Socorro, New Mexico 87801 505-835-5263 Telephone --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
