The research team found that, today, 16 percent of the US coastline – home to 1.3 million people, including 250,000 elderly people and 30,000 families below the poverty line, not to mention over $300 billion in residential property value – is in a "high hazard" area. The research team created the first-ever map showing a level of hazard risk for every square kilometer of shoreline.
"The places that are at high risk of hazards like flooding and erosion, from sea-level rise and storms, are also those places where there are a lot of people and a lot of coastal infrastructure," says Dr. Arkema. And while the most valuable property has the wealthiest people, there are miles of shoreline inhabited by some of the poorest in the country, she notes.
In addition to examining the current risk, Arkema and her colleagues considered four different possibilities for the future, using current trends and predictions from the Intergovernmental Panel on Climate Change's Special Report on Emission Scenarios. Their future possibilities range from maintaining current patterns, to two "middle of the road" scenarios, to one that assumes that the Greenland ice sheet has melted, says Arkema.
If the "middle of the road" sea level rise takes place by the end of the century, the situation on the seashore will get 30 to 60 percent worse, the scientists calculated. Their model didn't include commercial property, or any increase in population or property value, so their figures – including half a trillion dollars of property damage – actually represent a massive underestimate of the probable risk from coastal hazards.