Coastal resilience planning is a race between rising sea level and how much protective measure coverage a community can put in place before the shoreline erodes past use.
erosion_risk = sea_level_rise * (1 - adaptation_coverage*effectiveness)
- Coastline grid size — shoreline segments tracked for erosion and flood risk.
- Adaptation measure coverage — share of shoreline fitted with dunes, setbacks or wetland buffers.
- Sea-level rise rate — the pace of relative sea-level rise driving increased erosion risk.
- Measure effectiveness — how much erosion risk each adaptation measure actually removes.
Coastal communities that combined managed retreat with living-shoreline restoration held erosion rates steady even as neighbouring unprotected stretches lost metres of shoreline per year.