Arctic system on trajectory to new state, Jonathan T. Overpeck, Matthew Sturm, Jennifer A. Francis, Donald K. Perovich, Mark C. Serreze, Ronald Benner, Eddy C. Carmack, F. Stuart Chapin III, S. Craig Gerlach, Lawrence C. Hamilton, Larry D. Hinzman, Marika Holland, Henry P. Huntington, Jeffrey R. Key, Andrea H. Lloyd, Glen M. McDonald, Joe McFadden, David Noone, Terry D. Prowse, Peter Schlosser Sociology