Return on investment for mangrove and reef flood protection

There is a growing need for coastal and marine restoration, but it not clear how to pay given that environmental funding low, national budgets are stretched in response natural hazards. We use risk-industry methods find coral reef mangrove restoration could yield strong Return on Investment (ROI) flood risk reduction shorelines across more than 20 Caribbean countries. These results robust changes discount rates the timing of benefits. Data costs sparse, Present Value (PV) restored infrastructure shows ROI would be positive many locations even if hundreds thousand per hectare mangroves millions km reefs. Based these benefits, we identify significant sources restoring defenses.