- A model was created to measure the protective role of coastal habitat around the U.S. against storms and sea-level rise (1). The study concluded that “the extent to which natural defense mechanisms operate depends on the relative location of the hazard (for example, sea-level rise hotspots) (Sallenger et al. 2012), habitats, vulnerable populations and properties” (4).
- “Today 16% of the US coastline comprises ‘high hazard’ areas, harbouring 1.3 million people, 250,000 elderly, 30,000 families below the poverty line and US$300 billion in residential property value (Fig. 1)”(2).
- Results from future scenarios show that by the year 2100 “… more coastal segments will be highly exposed to hazards and that the amount of highly threatened people and property will increase by 30-60% over the current scenario (Fig. 1). Given modeled sea-level rise and observed storm characteristics (climate change), 1.7 to 2.1 million of today's population will live in areas exposed to the highest hazard (Fig. 1). Between 30,000 and 40,000 families below the poverty line and US$400 to US$500 billion of residential property will be most exposed to future hazards (Fig. 1)”(2).
- The study shows that “At present, habitats protect 67% of the coastline, as hazard increases in two-thirds of all segments in the scenario without habitat. Habitat loss would double the extent of coastline highly exposed to storms and sea-level rise (hazard index >3:36), making an additional 1.4 million people now living within 1 km of the coast vulnerable”(2). (Climate Change)
- Some regions around the U.S. are more vulnerable than others, specifically the east and gulf coasts where the coastal habitats are comprised of “softer substrates (for example, beaches, deltas)”, the tidal surges are stronger and the rates of sea-level rise are higher (2). These areas can be protected but substantial coastal forest, wetland and dune habitats are needed to buffer storm impacts.
- Coastal vegetation protects properties that value as low as $0 (Jefferson, Florida) to $20 billion (Stuffolk and Kings, New York) (3).
- In summary, mangroves play a critical role as bioshields: “…if the extensive coral, mangrove and seagrass ecosystems that line Florida at present persist in the face of coastal development and climate change, our analysis predicts these habitats will reduce exposure of nearly US$4 billion worth of 2010 home property values within 1 km of the coastline by 2100 up from US$0.7 billion at present (Fig. 3a,b insets)”(4).