Miami: A 20-Foot Sea Wall?

Sea Level Rise Oceans Miami

As sea levels rise, coastal cities are grappling with how to withstand increasingly frequent and severe storm surges that threaten entire communities. A New York Times report published last week focused on Miami in particular -- a city struggling to find a satisfying solution to sea-level rise.

According to the Times, Miamians have long accepted the reality of climate change -- the frequent extreme storms and hot nights have made the truth too obvious to overlook. However, few of the proposed protections have been appealing and/or effective enough for the city to implement.

Why This Matters

The issue of how Miami prepares for the effects of climate change could not be more urgent. Last year, Scientific American called Miami the "most vulnerable" city in the world when it comes to climate change and that as sea levels rise, Florida could suffer from "100 year floods" as frequently as every few years. Even worse, areas of Miami, namely Biscayne National Park and Miami Beach, could be permanently underwater by the end of the century.

Sea level rise projections by 2100 for two scenarios with the amount of rise in meters indicated (mild = 1m; extreme = 4m). Percentage and total population displacement indicated bottom right, yellow star on the city of Miami.

Miami's climate troubles are not limited to the effects of sea-level rise. In 2020, the city broke it's all-time June heat record two days in a row. Since then, Miami-Dade County has appointed a "chief heat officer" to address the rapidly rising temperatures.

Opportunity Cost

Even still, residents are hesitant to accept many proposed climate protections. Based on a study by the US Army Corps of Engineers (USACE), a proposal was made advising the city to build a 20-ft wall that would run parallel to the shoreline and through 6 miles of the city's neighborhoods. Such a project would cost $6 billion in construction alone -- not to mention the hidden cost of damage to surrounding ecosystems or property-value loss to nearby homes and businesses. Environmentalists and property-owners agree, the Times reports: No wall.

Other proposed solutions don't come with the guarantee of federal dollars that the wall does. As an USACE project, Congress would foot 65% of the bill. With the costs of climate preparation already accumulating beyond what the city of Miami can afford, this offer becomes difficult to refuse.

Still, few are on board. The public prefers an approach the Times calls "green infrastructure" -- the stacking of dunes, mangroves, coral reefs, and sea grasses to beat back rising tides. However, the USACE has expressed doubt that these methods would be sufficient. Per the Times article: "Officials with the corps, though, say -- gently -- that they see no way around what they call structural elements. The storm surge threat to Miami-Dade County is just too grave."

Earth.Org, August 6, 2020.

PBS: Planning for Rising Seas, January 5, 2020.