By Peter Schwartz and Doug Randall This public report, fully entitled \"An Abrupt Climate Change Scenario and Its Implications for United States National Security,\" was prepared by GBN for the Department of Defense. \"The purpose of this report is to IMAGINE THE UNTHINKABLE —to push the boundaries of current research on climate change so we may better understand the potential implications on United States national security,” stated the authors in their introduction. The report was based on interviews with leading climate experts and scientists. These experts agreed that the scenario described is extreme in two fundamental ways: the occurrences would most likely happen in a few regions, rather than globally, and the magnitude of the event may be considerably smaller.