quality is particularly difficult to hang a price tag on, because key factors change over time: the location and
kind of wetlands, and the number and value of houses behind them.
Researchers Fanglin Sun and Richard Carson assembled wetlands data published from 1996 and 2016 and
matched them to the tracks of the 88 tropical storms and hurricanes that hit the US during that period.
Their estimate is based not on the property values of the area surrounding those wetlands, but rather on the
cost of the damage caused by those storms.
The paper, published in the Proceedings of the National Academy of Sciences, “really provides a defensible,
economic estimate of the value of wetlands for this one purpose”, Carson says. “And clearly these values
aren’t anywhere close to zero. In fact, they’re giant.”
The estimate per square kilometre varies dramatically between highly populated, infrastructure-heavy
counties and rural ones, which explains why the median value – $90,000 (£70,000) – is so much lower than
the average. The wetlands protective value was even higher in areas with weak storm-related building
codes.
Hurricane Irma caused $50bn (£40bn) of damage in Florida when it hit the state as a Category 4 storm in
September 2017. Using the results from their study of the prior 21 years, Sun and Carson were able to
estimate how much damage would have been avoided if Florida hadn’t lost 2.8 per cent of its wetlands in
that period: $430m.
“This is substantial for a single storm,” they write, and conclude from it that “wetland preservation is likely
to be a comparatively effective way of protecting coastal communities against tropical cyclones.”
The study underscores the importance of wetlands to environmental protection on the Atlantic and Gulf
Coasts. The northeast in particular “is increasingly vulnerable to habitat loss and is increasingly exposed to
shocks and stresses attributable, in some part, to climate change”, says Jesse Keenan, a climate risk and
adaptation expert at Harvard.
“Hazard mitigation isn’t just about building codes and material solutions,” he adds. “Rather, the most
fundamental opportunity to adapt the built environment comes from innovations in preserving and
changing land use.”
Bloomberg