Topics Availability: Web-Only Year: 2026 DOI: https://doi.org/10.7249/PEA4610-1 Document Number: PE-A4610-1 Acosta, Joie D., Sara Hughes, and Jessica Jensen, Governing the Unknown: Insights from a RAND Workshop on Managing Polycrises and Catastrophic Risk, RAND Corporation, PE-A4610-1, February 2026.