When you hear the word infrastructure, you likely think of roads, bridges, and the electrical grid. But there’s also a category of nature-based solutions that are considered natural infrastructure: naturally occurring landscape features (or engineered structures that mimic landscape features) that can lessen the impacts of extreme weather—such as drought or flooding—while providing other ecological and human benefits.
ICF: To start, what separates coastal natural infrastructure from other types of natural infrastructure?
Carson Young: In our paper, the other authors and I created a definition of what we mean by coastal natural infrastructure. There are two requirements that a project must meet to qualify as coastal: 1) the project site must exist within 100 kilometers of the nearest coastline or 2) the project must explicitly relate to reducing coastal flood hazards.
One interesting thing to note is that our definition of natural infrastructure includes interventions that aren't natural but are engineered to act as or mimic a natural feature or process, such as an artificial reef or a living shoreline. The types of projects that qualify as coastal natural infrastructure can vary widely. In fact, the type of project that ends up being implemented depends on the amount of funding available and the type of benefits that match a location’s specific set of circumstances. For example, there are many barrier island projects off the coast of Louisiana, wetland restoration projects in Florida, and beach renourishment projects across the country’s coasts, wherever sandy beaches occur.
ICF: Can you briefly explain the methodology used for determining investment in coastal natural infrastructure?
Carson Young: Since protection and restoration of natural infrastructure are fairly new tactics to reduce coastal flood hazards, the core of this paper is developing a way to measure progress with these projects over time. An effective way to evaluate progress—and understand whether natural infrastructure is catching on as a cost-effective and reliable method to reduce coastal flooding hazards—is to track investments made in qualifying projects.
So a key part of our methodology is a decision framework that establishes a way to determine whether projects actually have coastal flood hazard reduction benefits. This framework allows us to get to the crux of the issue and eliminate any “noise” in the data by removing projects that don’t reduce flood hazards. We also remove gray infrastructure
and other natural infrastructure projects that may have benefits but have little or nothing to do with flood hazard reduction.
ICF: Why is it important to track the U.S. investment in natural infrastructure?
Carson Young: Tracking investment can show us where there is interest in these types of projects and can help determine whether policies, laws, and programs are facilitating implementation. If we know how much money is being spent and where, it could give us a sense of which states and communities are taking climate resilience most seriously. Having this type of data available in the literature could also lead the way for future analyses that explore whether the areas that have high levels of vulnerability to climate impacts are the same areas that are investing the most in coastal natural infrastructure to grow their climate resilience.
That being said, data availability can be an obstacle with these types of analyses. During our research, it was surprisingly difficult to find easily accessible and adequately detailed information for some funding sources. Better public recordkeeping and funding transparency would improve the accuracy of our findings. But the good news is that we found that investment in coastal natural infrastructure is increasing. The level by which it is increasing is variable year to year, but we can say that there is a clear increasing trendline for the years we examined in the paper.
The audience for a quantitative tracker of funding and projects to achieve flood reduction benefits is any entity—government leaders, or NGOs—looking at how to get more funding into effective forms of flood protection. Equipped with good information, these are the stakeholders that can impact the national conversation around climate resilience.
ICF: Speaking of resilience, is your model able to adapt to climate change’s future impacts?
Carson Young: Yes, the decision framework is both reproducible and adaptable to guide future investment tracking efforts. With small changes, the framework could even be refocused to track natural infrastructure projects with benefits other than flood hazard reduction, such as habitat enhancements for wildlife or carbon capture ability. Remember that our definition of coastal natural infrastructure includes projects within 100 kilometers of the nearest coastline, so it allows for flexibility as bigger, stronger storms plus rising sea levels cause shifting shorelines and flooding impacts farther inland.
As climate change increases the risk and severity of coastal flooding in the U.S., the hope is that we continue to see growth in funding for natural infrastructure projects to cope with this higher risk. Fortunately, we now have a reliable way to track progress.