The best defense against hurricanes may be nature itself
While climate change did not create damaging weather events and wildfires, it has demonstrably made them more extreme and punishing. There is a credible foreboding among many South Floridians as we enter the 2021 hurricane season. Since 1851, a staggering 120 hurricanes, more than 41% of hurricanes that hit the U.S., made some sort of landfall in Florida, with MiamiFort Lauderdale-West Palm Beach the most susceptible to hurricanes with storm surges and plentiful rain causing severe damage. Today, as climate change advances, the Earth has heated up sufficiently to produce rising sea levels and warmer oceans, which in the past 20 years has triggered even more severe and frequent storms, inflicting an increasing loss of property and lives.
The coastal communities in southeast Florida that have grown among the wetlands and barrier islands that can buffer against storm damages are facing serious questions about managing the threat of ferocious storms. Do they build massive seawalls to protect our infrastructure? Do they give up on our current coastal location and retreat inland? One solution floated in June by the Army Corps of Engineers was to build a 20-foothigh giant seawall running parallel to the Miami coast. The $6 billion proposal remains tentative and at least five years off, but it is sure to be among many proposed solutions in the coming years to protect coastal communities from storms.
Recently a new study revealed more expansively than ever before the promise of nature itself — healthy coastal wetlands — to avoid damages and save lives. The accuracy of the study’s findings takes advantage of state-of-the-art storm tracking, enhanced global land use mapping and global damage assessment databases, along with improved computational capabilities that combined to assess the relationships between coastal wetlands and avoided damages and deaths from tropical cyclones.
The researchers used the historical tracks of over 1,000 tropical cyclones since 1902 that recorded property damage and/or human casualties in 71 countries/ regions and found that an estimated $450 billion in economic damage would be prevented by coastal wetlands mitigating the impact of tropical storms and 4,600 lives would be saved every year. The United States alone saves $200 billion in annual avoided damages from storms and saves 469 lives because of wetlands.
The way that coastal wetlands work is to protect shorelines with “horizontal levees” that are maintained by nature and are far more cost-effective than constructed levees or seawalls. The mechanisms involved include decreasing the area of open water for wind to form waves, increasing drag on water motion and hence the amplitude of a storm surge.
Coastal wetlands also provide a host of other valuable ecosystem services that constructed seawalls do not, such as nursery habitat for many commercially important marine species, recreational opportunities, and management of sediment and nutrient runoff.
But changes in land use, which includes the loss of coastal wetlands, are reducing the extent and total value of the ecosystem services they can provide. Since 1900, the world has lost over half of its wetlands. The new data shows that reversing this trend and investing in the maintenance and restoration of coastal wetlands is an extremely cost-effective strategy for significantly mitigating storm damage, and in the larger picture, can increase well-being for humans and the rest of nature. Indeed, the emerging evidence shows our economy, our lives and our very civilization depend on a healthy planet and functioning ecosystems.
The frequency and intensity of tropical cyclones and other extreme weather events in recent decades is unfortunately increasing, and projections point to further increases with climate change. As Florida (and the world) considers solutions to protect lives and property from the onslaught of coastal storms, much larger investments in the conservation and restoration of coastal wetlands and other natural ecosystems are clearly justified and deserve our life-saving attention.