Rising sea levels from climate change pose a serious threat to coastal cities around the world, but national parks are also at risk.

A new report from the National Park Service says sea level rise at 40 coastal national park sites, including eight in California, will put $40 billion worth of assets at high exposure. The estimate, it said, is almost certainly on the low side.

The 40 park units contain 10,000 assets, including roads, buildings, bridges, water systems, parking lots, tunnels, sea barriers, lighthouses, fortifications and archaeological sites. The study designates each asset as having high, intermediate or limited exposure.

However, “A quick reassessment of the methodology contained within this report following Hurricane Sandy suggests that we have been conservative in labeling an asset as high exposure." 

The report assumes that sea levels would rise 1 meter, or 3.28 feet, in the next 100 to 150 years. That’s a number it is more comfortable projecting than the actual elevations of the assets. The executive summary (pdf) closes with a warning that the report should not be used for decision making at the unit level because accurate elevation data was unavailable for the “vast majority” of the assets from its chief source, the already-existing Facilities Management Software System (FMSS) (pdf) database.

That said, 39% of the assets are labeled high exposure. Parks in the Southeast U.S. are the most vulnerable, with 100% of assets in nine of the 13 park units at “high” risk. The Northeast was next worse, followed by the Pacific West and Intermountain regions.    

Six of California’s park units are “low,” two are “intermediate” and none are at “high” risk, although assets within them get the scary high rating.

Golden Gate National Recreational Area has the most assets at risk. Eighty-nine percent of its 1,049 assets are deemed “low” risk and 11% “high” with a “current replacement value” of $617.6 million.

San Francisco Maritime National Historical Park has 43% of its 49 assets at “high” risk with a value of $262.7 million. Five of the 17 assets at Fort Point National Historic Site are “high” risk ($191.2 million), as are 14% of Channel Islands National Park’s 166 assets ($46.7 million). Point Reyes National Seashore has 4% of its assets at “high” risk ($34.9 million) as does Redwood National Park ($7.9 million).  

Cabrillo National Monument and Santa Monica Mountains National Recreation Area do not have assets at “high” risk.

These are not all the parks at risk. A second study of an additional 30 parks is already underway.

–Ken Broder

To Learn More:

Climate Change Could Cause More than $40 Billion in Damage to National Parks (by Annie Wang, ThinkProgress)

$40 Billion of National Parks at Risk from Sea Rise (by Jim Waymer, USA Today)

Coastal Assets Report (National Park Service)