Owen B Toon, Univ Colorado Boulder, Boulder, CO, United States, Charles Bardeen, National Center for Atmospheric Research, Boulder, CO, United States, Alan Robock, Rutgers University, New Brunswick, NJ, United States, Lili Xia, Rutgers Univ, New Brunswick, NJ, United States, Hans Kristensen, Federation of American Scientists, Washington, United States, Matthew McKinzie, Natural Resources Defense Council, Washington, United States, Roy J. Peterson, University of Colorado, Boulder, Department of Physics, Boulder, CO, United States, Cheryl S Harrison, University of Texas Rio Grande Valley, School of Earth, Environmental and Marine Science, Port Isabel, TX, United States, Nicole S Lovenduski, University of Colorado, Department of Atmospheric and Oceanic Sciences, Boulder, CO, United States and Richard P Turco, UCLA, Los Angeles, CA, United States