Last week we posted an activity for kids focusing on the concept of “storm surge.” Then, I read an interesting article yesterday, and it got me thinking a bit. My husband and I even had a debate about this subject in the car last night because my brain kept going back to the article over and over. I just couldn’t seem to shake it. The topic of the article: “sea-level rise.”
And while “sea-level rise” is not exactly the same as “storm surge,” they are related, so hear me out. Climate change is a big deal. We have come to a point where ignoring or denying that the climate is changing is no longer an option. For the record, we should be concerned that our home on this planet is in peril because of our own actions. The real problem is that many people don’t understand how climate change works, and why it leads to some of the catastrophic results that we’re seeing all across the planet, like sea-level rise. We need to take serious action to combat climate change. And my fear is that we do not have the tools or the will — politically or otherwise – to effect real change.
So, back to our first topic, how are sea-level rise and storm surge related? Well, imagine that a Category 3 hurricane swooped up the Eastern Seaboard, collecting energy from warm coastal waters as it moved, gaining speed, and then made landfall somewhere along North Carolina’s Outer Banks. We’ve seen this before. What happens? As the storm approaches land, the water doesn’t have room to spread out as it does in the open ocean. Both wind and pressure cause the water to pile up, creating a surge of water that is forced up onto the land. The National Hurricane Center (NOAA) has some really great drawings of how this occurs.
The most damaging part of a hurricane is usually the storm surge. The height of the surge varies from one storm to the next depending on so many factors like the size of the storm, wind speed, pressures within the storm, the path of the storm, the angle at which the land sits in relation to the storm, and coastal features such as bays and estuaries.
I’m going to repeat that last part because it is VERY important: Coastal features. The shape of the coastline along with its natural features like bays, estuaries, marshes, seagrass beds, oyster beds, sand dunes, maritime forest, and barrier islands all help protect the coastline by absorbing energy from the waves so that they are not able to reach further inland to damage homes and destroy towns. When those features are damaged the coastline loses its natural protection mechanisms (see the image below). It no longer has a safe buffer from the storm surge. This is a very good reason to protect our natural coastline. I’ll come back to this in a minute.
You’re still wondering how sea-level rise fits into this equation, and I haven’t forgotten that part of the story. As climate change increases global temperatures (currently by ~2℉ over the past 150 years), ice in the planet’s coldest spots cannot remain in solid form. It has started to melt. Glaciers have shrunk dramatically in size (read this past blog post), ice-covered mountain peaks have rock peeking through, and the floating ice shelves covering our poles are losing acreage due to warming seas. The addition of so much extra water to our warming oceans will inevitably lead to a rise in sea-level along all coastlines. But those coastal areas that are particularly low in reference to sea level will be hit the hardest, like those in the Southeast United States. A new sea-level is on the rise…all puns intended, however scary that may be.
I probably don’t need to tell you that when water levels become higher, and the protection mechanisms of the natural coastline are already decreased, any storm surge that inundates land at that point will immediately cause worse damage than it would have with a lower sea level and strong natural fortification along the coast. But there are other concerns too, because climate change has so many effects on so many different parts of our planet. As the seas are warming, cyclonic storms (like hurricanes) become larger because they build more energy from warmer waters. Warmer seas year-round also have an unpredictable effect on weather systems and patterns as greater evaporation leads to bigger fuller clouds during unusual times of the year or in unusual locations on the planet. Oh, you weren’t expecting a snowstorm in April? Well, there is a new norm everywhere.
I mentioned previously that we would come back to the need to protect our natural coastline. North Carolina’s natural native coastline was a glorious thing. Some parts of it still are. Barrier islands gently curving along, mirroring the shape of our eastern border. They protect the estuary system behind that harbors one of the most productive ecosystems on the planet. Wetlands that hold more carbon than any forest could dream of holding. Rolling sand dunes deflect wave energy without flexing a muscle. The bottom line here is that a healthy coastline will help protect us, so how do we maintain a healthy coastline? We have to build more responsibly.
Returning to the article I was reading – it was about coastal cities and towns in the UK. Centuries ago, the marshes and estuaries were filled in to make farmland and to allow the wealthy to ride their horses home more easily instead of having to take a ferry to the outer islands. As a result, hardened surfaces have been rebuilt every year to fight back the sea with price tags in the hundreds of thousands of dollars. These towns and villages are often inundated with water, sometimes yearly, requiring extensive repairs, despite the funds being wasted on preventive measures that don’t prevent anything. But finally, the British government and the public are working together to give the land back to the sea. It’s hard to fight Mother Nature. She always wins. The inevitability of sea-level rise only makes this decision more sound. If we stand a chance of fighting climate change, we have to learn to let the water have its way. A hard lesson it may be, but it’s one that we strongly need to consider along the North Carolina coast.
If you’re looking for more information about storm surge damage and rising sea-level specifically on the North Carolina coastline, check out Chapter 30, “Cape Hatteras” in “Thirty Great North Carolina Science Adventures,” published by UNC Press.
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References
Costanza, R., Anderson, S., Sutton, P., Mulder, K., Mulder, O., Kubiszewski, I., Wang, X., Liu, X., Pérez-Maqueo, O., Martínez, M. L., Jarvis, D., & Dee, G. (2021). The global value of coastal wetlands for storm protection. Global Environmental Change, 70, 102328. https://doi.org/10.1016/j.gloenvcha.2021.102328
Smith, A. C., & Carrier, S. J. (2020). Thirty Great North Carolina science adventures: From Underground Wonderlands to Islands in the Sky and Everything in Between. The University of North Carolina Press.