This book examines and challenges related and analogous arguments regarding the implications of geographical change for maritime boundaries. It attempts to clarify the principles and presumptions bearing upon an assessment of the fluidity of boundaries generally. Finally, it considers and contests claims that entitlement to maritime space will be lost if the features generating such entitlement are submerged by rising seas. This analysis is extended in a comment on the implications of a loss of habitable land and large-scale population displacement for continuing territorial sovereignty and statehood. The in-depth analysis of the existing law in this book offers new answers to the question of the implications of geographical change for entitlement to maritime space, maritime limits, and international maritime boundaries.