The Paris Agreement's goal to hold warming to 1.5°-2°C above pre-industrial levels now appears unrealistic. Profs. Robin Kundis Craig and J.B. Ruhl have recently argued that because a 4°C world may be likely, we must recognize the disruptive consequences of such a world and respond by reimagining governance structures to meet the challenges of adapting to it. In this latest in a biannual series of essays, they and other members of the Environmental Law Collaborative explore what 4°C might mean for a variety of current legal doctrines, planning policies, governance structures, and institutions.