Dr. Michael MacCracken is Chief Scientist for Climate Change Programs with the Climate Institute in Washington DC. Mike spent most of his career at Lawrence Livermore National Laboratory (LLNL) as an atmospheric physicist, researching the causes of climate change, climatic effects of greenhouse gases, volcanic aerosols, land-cover change, and nuclear war, and investigating factors affecting air quality. From 1993-2002, he was on assignment from LLNL as senior global change scientist for the interagency Office of the U.S. Global Change Research Program (USGCRP), serving as the Office’s executive director from 1993-1997 and as executive director of USGCRP’s coordination office for the U.S. National Assessment from 1997-2001. During this time, he also coordinated preparation of the official U.S. Government reviews of IPCC’s second and third assessments, serving also as a contributing author on several IPCC chapters and as review editor for the North America chapter for the fourth assessment. Since retiring in 2002 after 34 years with LLNL, Mike has, in addition to his activities with the Climate Institute, served as president of the International Association of Meteorology and Atmospheric Sciences from 2003-2007 and as a member of the Assessment Integration Team for the Arctic Climate Impact Assessment from 2002-2004. From 2005-2007, he served as a co-lead author for the report Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable that was prepared for the United Nations Commission on Sustainable Development by Sigma Xi and the United Nations Foundation.