Nature as a Tool: Using Natural Infrastructure to Reduce Extreme Weather Damage

Whether from wildfires in California or flooding in Florida, the costs wrought by extreme weather events continue to grow. In 2024 alone, 27 separate weather- or climate-related events—ranging from flooding and severe storms to wildfires and winter storm events—produced losses in excess of $1 billion. In response to these hazards, many communities and governments have built seawalls, levees, or infrastructure to minimize future damage. While such traditional projects can help reduce weather impacts, they also have drawbacks: Not only can they be expensive to build and maintain, they can also disrupt natural ecosystems or lead to other negative downstream consequences.

Governments must consider all options when contemplating such projects and give special consideration to projects that leverage natural infrastructure to help protect against extreme weather risks.

Natural Infrastructure Defined

“Natural infrastructure” refers to features of the natural environment that can serve to protect individuals and property from the harmful effects of weather events or that help to minimize those effects. Just as a built structure (e.g., a levee) may protect against extreme weather, natural features of the environment can have similar effects.

To illustrate this, consider the role mangroves can play in mitigating storm surge. Winds from hurricanes can cause a rapid and substantial increase in sea levels in a given area, flooding homes and other structures near the coast. Mangroves—densely packed salt-tolerant trees or shrubs found in warmer coastal areas—have several features that blunt storm surge, including the ability to dissipate or absorb energy from storm-caused waves in order to protect inland properties. One study found that 330 feet of mangrove trees “can reduce wave height by 66 percent.” The reduction in storm surge from this natural infrastructure translates to a reduction in storm damage. According to a study of Hurricane Irma, mangroves prevented an estimated $1.5 billion in damages in Florida.

Mangroves are not the only geographic feature that can reduce damage from storms and flooding. Marshes, wetlands, and coral reefs also have protective benefits—in fact, a mere 15 feet of marshes can reduce wave energy by half. Marshes reduced storm damage from Hurricane Sandy by about 16 percent, while wetlands reduced damage by 10 percent. And coral reefs can reduce wave energy by as much as 97 percent.

Natural infrastructure can also help with non-coastal flooding. Tree cover can create a “canopy effect” that slows the rate of rainwater accumulation while tree roots reduce runoff by allowing water to be absorbed deeper into the soil. The exact degree of flood protection provided by tree cover is a matter of dispute, with estimates of the flood-protective benefits of forests ranging from $41,000 per hectare per year to as low as $1 per hectare per year.

Wildfires are becoming particularly damaging in parts of the western United States, and attempts to suppress small fires play a role. Without periodic naturally occurring blazes to clear out an area, woodlands can become overgrown with small trees and dead wood that increase the odds of a small fire growing into a massive and costly disaster.

Natural vs. Built Infrastructure

In some cases, natural infrastructure does a better job at reducing damages from extreme weather than built infrastructure designed specifically for that purpose. Built storm mitigation infrastructure can itself be damaged by storms in ways that natural infrastructure cannot. For example, approximately three-quarters of the bulkheads in North Carolina’s Outer Banks required repairs following Hurricane Irene, while wetlands were unaffected. Natural infrastructure is also more adaptable to changes in the natural environment (e.g., sea level rise, which can render levees and bulkheads ineffective). This is not an issue for marshes, which collect sand and sediment from rising water.

A 2018 analysis by the United States Army Corps of Engineers (USACE) found that natural infrastructure projects often had a more favorable benefit-cost ratio than built projects, even when excluding environmental and health benefits from the calculation. A 2014 study by the National Academy of Sciences noted that in addition to their protective benefits, natural infrastructure often had economic benefits in terms of tourism and recreation that made the overall benefit-cost ratio higher than for traditional projects. Activities like fishing, bird watching, or beachcombing provide value to individuals both economically and in terms of human welfare.

Natural infrastructure projects have been implemented successfully in various situations. USACE’s analysis details eight projects that used natural infrastructure, and New Orleans has been experimenting with permeable sidewalks, rain gardens, and other devices to reduce runoff and flooding.

Natural Infrastructure Policies

It would be a mistake to think that using natural infrastructure to protect against extreme weather is costless; some cases involve restoration projects that carry significant cost, and preservation may incur opportunity costs from foregone development. These costs must be taken into account when determining whether natural infrastructure is the best mitigation strategy in a given case.

That said, there are things governments can do to maximize the value of natural infrastructure. First, when considering options for extreme weather mitigation, a government or other body should seriously consider natural infrastructure. America’s Water Infrastructure Act of 2018 required USACE to consider natural infrastructure options when considering flood mitigation projects. Similarly, Louisiana has incorporated natural infrastructure as a consideration in its flood mitigation strategies.

Another policy is not to subsidize development in areas that would destroy or reduce the protective benefits of natural infrastructure. If the economic value of a development that would result in the uprooting of mangroves in a given area is greater than the protective value of those mangroves, then the development ought not to need government subsidies in order to proceed. The Coastal Barrier Resources Act enacts this general philosophy at the federal level. It does not prohibit development; instead, it prevents federal subsidies from being used for development in 3.5 million acres of wetlands, barrier islands, and other environmentally sensitive areas.

Conclusion

Civilization has always dealt with the perils of extreme weather, but recent trends show that the damage from extreme weather events is rising. Not only is minimizing the damage from such events necessary to preserve human life, it also helps keep the cost of living from skyrocketing. But reducing the cost of extreme weather can itself cost money, and it behooves us when adopting such measures to choose the option that gets us the most value for our money. Natural infrastructure is one such option.