New Study on the Value of Coastal Wetlands

From a recent Greenwire Press Release:

U.S. coastal wetlands provide more than $23 billion in annual storm protection services to cities and regions most vulnerable to hurricane and tropical storm surges, according to a study released today.The University of Vermont’s Gund Institute for Ecological Economics prepared the study, which finds that “coastal wetlands provide ‘horizontal levees’ that are maintained by nature and are far more cost-effective than constructed levees.”

Moreover, the researchers said, “If the frequency and intensity of hurricanes increases in the future, as some are predicting as a result of climate change, the value of coastal wetlands for protection of these storms will also increase.”

The findings, while part of a broader body of research on the value of coastal wetlands, are relevant for policymakers because they provide a rare glimpse at the financial impacts associated with wetland losses in storm-prone areas.

The study found wide variability in wetlands’ protective value between coastal areas on the Atlantic Ocean versus the Gulf of Mexico, depending upon the number of wetland acres present and the value of infrastructure behind such wetlands.

Louisiana, for example, had the most wetland acres but less threatened infrastructure than either Florida or Texas, thus driving down the protective value of the state’s wetlands. New York, Connecticut and Massachusetts, meanwhile, had fewer wetlands but very high infrastructure values, given real estate values along the Eastern Seaboard.

But Louisiana’s higher frequency of destructive storms makes the economic impact of its wetlands losses particularly acute. For example, as a result of the disappearance of coastal wetlands in Louisiana before Hurricane Katrina, additional wetlands vanished during the hurricane, and the resulting lost protection of infrastructure, crops, housing, revenues, employment and stable markets was valued at $1.1 billion.

The researchers drew their findings from regression modeling done for 34 major U.S. hurricanes dating back to 1980, including 2005’s record-breaking year for both the number of storms making landfall in the United States and their devastating economic impacts. The models estimate that 1 hectare (2.47 acres) of coastal wetland loss corresponded to an average $33,000 increase in storm damage from specific storms.

The research was published in AMBIO, a journal of the Royal Swedish Academy of Sciences focused on environmental topics.