Harvard s program on Sea-Level Investigation and Management explores storage of water on and under land at volumes that matter for global sea level, and what such storage is worth. Candidate measures include stabilizing over-pumped aquifers, injecting water into deep geologic formations, and diverting seawater into below-sea-level depressions. Any of these may prove technically impossible, economically infeasible, or too costly to society. Existing knowledge does not permit dismissing them, howe...