The executive summary reviews the origin of the Florida Keys climate change project and then describes the technique of scenario planning, followed by a description of the four main global scenarios of the Intergovernmental Panel on Climate Change in their original form, and how and why they were updated for this project. These global sections are essential for understanding the Florida Keys projections, which are developed under four headings: a short general description and review of main strengths and vulnerabilities; how the local indicators of climate change were linked to the global indicators; presentation of the local scenarios in narrative and graphic form; and policy recommendations.