The Loss of Louisiana Marshes to Sea Level Rise Puts New Orleans Real Estate at Risk

Over the course of the last several decades, people have come to recognize the value of coastal marshlands as both incubators of aquatic birds and marine life and as buffers to floods and storm surges that can quickly inundate valuable real estate. A recent study published on the American Academy for the Advancement of Science’s Science Advances website reached the troubling conclusion that sea level rise is occurring at such a fast pace that the marshes that protect New Orleans and surrounding communities could vanish beneath the waves in the next fifty years.

Scientists studied over 8,000 years of marsh history to determine that the marshes have reached a “tipping point” where they are being consumed by the ocean faster than they can adjust to higher sea levels. The study’s lead scientist, Torbjorn Tornqvist, a professor of geology at Tulane University, told the Washington Post that even with efforts to reduce the production of earth-warming greenhouse gases, the marshland’s fate could be sealed. “We know the rate of sea level rise, even with the best action you can imagine, it’s still going to ramp up further,” he said. “Given the slowness of the ocean responses, it’s going to last for a very long time.”

The ocean has been gnawing away at the protective marshlands for decades. Experts blame the loss on the penning in of the Mississippi River channel, which used to spread land-building sediment broadly across the river delta, and on channels cut through the marshes for petroleum company pipelines. Louisiana is trying to reverse some of the damage by diverting some of the river’s sediment-rich flow out of the manmade channel and onto adjacent lands.

Professor Tornqvist sees this as a way to buy time that ultimately won’t save the city from inundation. “I think a couple of decades is incredibly valuable,” he said, “because it could be the difference between a somewhat managed retreat verses complete chaos.”

The researchers believe their study could prove valuable to all coastal communities that rely on marshlands as a buffer against sea level rise flooding and storm surges. “Our findings highlight the need for consideration of longer time windows in determining the vulnerability of coastal marshes worldwide,” they wrote in their study abstract.

The takeaway for buyers and owners of real estate in coastal areas protected by marshlands is to recognize that they’re not wastelands but a critical part of the ecosystem that protect their property from flooding. With that in mind, it’s important for them to learn about the health of the local marshes as well as their predicted life-expectancy under pressure from sea level rise.

Are Dredging and Beach Replenishment Effective Ways to Protect Real Estate Against Sea Level Rise?

In this video, a massive dredger scours sand and mud from the seafloor off Delray Beach, Florida, and pumps it onto the land where it’s used to replenish the eroded beach. The $8 million project is intended to rebuild the beach for tourism and to protect millions of dollars in real estate.

Every year, cities along the Atlantic, Pacific and Gulf of Mexico coastlines spend millions of dollars on beach nourishment projects. In my hometown, Delray Beach, Florida, a massive offshore dredger just started pumping slurry — sand and water — onto the seriously eroded beach to replenish it. The $8 million project is expected to last weeks. (You can see how it works by watching the video I created of the project.)

This type of dredging to replenish a beach has benefits and costs. In our case, the cost of beach replenishment is easily offset by the tourist dollars it attracts to the community. Without a beach, it’s unlikely people would come here and spend money to stay in hotels and dine and shop in the bustling downtown district. The beach also lures real estate buyers into purchasing single family homes, townhouses and condos.

Beyond the economic advantages, the replenished beach also acts as a barrier that protects valuable real estate from storm surges and erosion.

Despite the many positives, beach replenishment has some downsides. It can be harmful to marine animals and shore birds. If the causes of erosion aren’t (or can’t) be addressed, it will have to be repeated on a regular basis. And it can be expensive; and the costs are growing, especially in areas where sand is not in abundance and it has to be trucked in.

Sea level rise is sure to exacerbate the challenges faced by towns that rely on sand replenishment to maintain their beaches. Every inch of sea level rise increases the force of tides and wave action on beaches. The higher and more powerful storm surges that come with climate change and sea level rise will also be problematic.

For now, most cities and towns that rely on beach replenishment appear committed to the practice to protect their tourism trade and valuable real estate. Whether they will be able to foot the bill when the seas get higher and their beaches require more frequent nourishment projects is an X factor that all real estate buyers and owners in coastal areas prone to erosion need to consider.

California Town Embraces Retreat to Address Sea Level Rise Threat

“Resiliency” and “retreat” are two popular buzzwords regarding sea level rise and real estate. Resiliency is making the changes necessary to prevent sea level rise flooding as long as possible so people can continue to live near the coast. Retreat is recognizing that either the cost is too high or it’s impossible to engineer your way out of the flooding, so everyone has to move back away from the coastline.

Currently, resiliency is the solution most coastal cities and towns are using to address sea level rise. Governments and property owners are spending billions of dollars to elevate property and critical infrastructure, such as pipes and roads. They’re also building and/or raising sea walls and installing pumps.

Retreat is far less popular. From the Florida Keys to the Pacific Coast, property owners are fighting plans that would force them to move away from coastal areas that are subject to sea level rise-driven flooding or at great risk of flooding in the near future.

According to an article in the Los Angeles Times, Marina, California, a small town with 23,000 residents north of Monterey, is actively embracing retreat as a solution to its sea level rise woes. The town is considering plans that have proven unpopular in most coastal locations, including requiring sellers to disclose sea level rise information to buyers, moving infrastructure away from at-risk areas, and discussing relocation with the operators of a private beach resort.

To ensure that the town doesn’t have to make the same difficult decisions over-developed towns are being forced to make regarding resiliency or retreat, Marina officials are actively steering real estate developers toward inland locations away from the eroding shoreline.

David Revell, a coastal scientist and sea level rise consultant, told the Times, “Marina is such a good test case. Here we have the precedent of a community that understands that … there has to be enough lead time to get things out of the way — before it’s in the way.” Revell added that Marina’s pro-active approach “is a really powerful message to the rest of California.”

Residents seem to generally approve of the town’s approach to dealing with sea level rise. The town’s draft plan is almost finished.

Real estate buyers in coastal areas need to consider whether a city or town intends to rely on resiliency or retreat to address sea level rise flooding. Resiliency can lead to higher taxes and the possibility that a property of interest will be impacted by the construction of sea walls, pump stations and other infrastructure. Retreat could limit the amount of time a property can be owned and enjoyed. Both approaches could also impact property value.