As sea levels rise, they are not simply coming higher, but they are reshaping the coastlines as they come up. This can lead to erosion occurring at faster rates and in new places. It also changes the shape of our beaches and barrier islands and can be the driving force behind relocating or reducing critical habitats, such as marshes and upland forests.
These changes can have many ripple effects; one very noticeable and important change is how storm surge changes with rising seas. Not only does a higher sea level mean higher storm surge, but the changes to the shoreline can lead to even more dramatic changes in surge.
For example, a 1-foot increase in sea level could translate to a multiple-foot increase in surge height in some places (see figure below). This means that new areas are at risk to storm surge and that adaptations we have already made to accommodate storm surge, such as elevating our homes, will not be sufficient as the surge will be even higher.
Quantifying the economic impact
The good news is that there are researchers, led by a team at LSU’s Center for Coastal Resiliency, who have done in-depth modeling to understand how the shoreline may change under rising seas and how that will impact storm surge. You can see changes to a 1% annual chance event, sometimes known as the 100-year floodplain, at www.gomsurge.org. You can also see how surge from a big storm like Hurricane Katrina may look different with higher sea levels.
In addition to understanding how the surge is expected to change, researchers led by Harte Research Institute have been exploring the economic and societal impact to the changes in surge along coastal Mississippi, Alabama and northwest Florida. Thanks to their work, we have estimates of how many more buildings may be impacted, the cost of those damages, how many people may be displaced, how shelter needs may change, transportation infrastructure that will become vulnerable, and which critical facilities may become at risk as storm surge changes.
What can we do with this knowledge?
This information at times can feel overwhelming, but knowledge is power! By understanding how the floodplain may change, we can begin to consider changes in building requirements and zoning. We can also consider relocating critical facilities or better prepare them for higher water. There are a multitude of approaches that can be used. Further, understanding the relative increase in storm surge damage costs provides a context for how much money we can save by adapting. We have estimates for the entire southeast that show strategic adaptation can avoid more than $300 billion dollars in damages by 2050. This new information will let us understand exactly how much of that may apply to our coastlines.
The maps with all the economic information are not available yet – but they will be soon, so keep your eyes open for that information! In the meantime, you can talk to your neighbors about sea-level rise and changing surge. If you have any questions or want to learn more about how you can address changing flood risk in your community, the Northern Gulf Sentinel Site Cooperative staff is always happy to help! Check out our website for emails and other projects.
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