Sea-level rise is an existential threat to coastal residents around the world as it progressively raises water levels, promoting increased flooding, erosion, salinization, and ecosystem degradation and loss. Unmitigated climate change will lead to rapid acceleration, with a meter of rise by 2,100 appearing likely and larger rises possible. Although some coastal areas are already being inundated, many others will increasingly suffer from rising sea level and more intense extreme water levels during high tides, winter storms, and hurricanes in the future. Small islands, deltas, and coastal cities are particularly threatened.