Could America’s Future Capital Be Underwater? Scientists Say It’s Plausible Climate Central

It’s hard to imagine a different version of the scene in the American mind when you stand on the Mall in Washington on a clear morning and look west toward the Lincoln Memorial with the Reflecting Pool stretched out between you and the monument. One in which the same geography is frequently flooded, where the streets surrounding the Mall are only passable during specific seasons, and where the buildings housing American government must be managed against encroaching water rather than just occupied. The extinction of Washington is not anticipated by scientists. However, on a timeline that comfortably fits within the lifespans of people currently in middle age, they are recording, with ever-increasing precision, the conditions under which parts of it become noticeably more flood-prone than they are today.

The East Coast is identified as a specific susceptibility zone by Climate Central’s estimates, which combine sea level rise data from several research sources and model coastal flooding exposure for communities across the United States. Due to both ocean warming and the unique dynamics of the Atlantic circulation system, as well as in some places land subsidence—where the ground is actually sinking at the same time as the water is rising—sea levels on the East Coast are rising two to three times faster than the global average. The 2050 estimates for cities like Miami and New York appear less like far-off scenarios and more like planning horizons that infrastructure decisions are now beginning to take into account because of the combination of those two elements. Despite having a less severe risk profile than Miami, Washington, D.C., which is situated on low-lying terrain between the Potomac and Anacostia rivers, is part of the same regional susceptibility pattern.

When demonstrating the urgency of the issue, climate experts most frequently turn to Miami, and the city’s everyday reality already warrants their attention. In some portions of Miami Beach and the neighboring communities, sunny day flooding—seawater backing up through storm drains during high tides without the need for a storm—has become a common occurrence. In order to buy time without addressing the fundamental problem, the city has invested hundreds of millions of dollars in pump infrastructure and road upgrades. According to projections, sea level rise over the next few decades will be greater than what existing adaptation efforts can handle, even with major reductions in emissions. Miami is now essentially asking itself, as are other vulnerable cities, how long the adaptation strategy can last rather than whether to adapt.

A West Coast perspective is added to the image by the San Francisco Bay Area. According to the Climate Central data, areas like Foster City and Fremont that were built on low-lying bay borders during the building boom of the mid-20th century are at a high risk of experiencing significant flooding by 2050. Although the Bay Area’s experience with sea level rise differs slightly from the East Coast pattern (the local rate of rise is somewhat slower and the geological situation is different), the combination of developed low-lying land and an increase in high-tide flooding events follows the same basic logic. Levee systems, which were built for the sea level levels of the twentieth century and are currently being reevaluated for the conditions anticipated in the twenty-first, have been used for decades to control portions of the Bay’s shoreline against floods.

In this discussion, Florida as a whole has a unique position because it is the state where the projections are most viscerally readable due to physical location. A large chunk of South Florida is only a few feet above the current sea level, and a large portion is at altitudes of less than 10 feet. Because the limestone beneath the peninsula is porous, flood barriers constructed to keep off surface water cannot stop water from seeping up from below. Geology in Florida limits technical alternatives that are effective elsewhere, like as levees, seawalls, and pump systems, making adaptation far more difficult and costly than in other coastal areas.

Financial institutions are starting to factor in the disruption to the real estate and insurance markets caused by the approximately three million buildings that Climate Central identifies as being at risk from a 1.6-foot sea level rise, which is thought to be feasible by 2100 under even optimistic emissions scenarios. Coastal Florida’s property insurance market has already seen a sharp decline, with several large insurers pulling out completely in recent years. Private capital withdrawing from a risk category that it no longer thinks it can price properly enough to stay profitable is a signal in and of itself.

Working through the forecasts for different locations and the varied timescales they provide gives the impression that the United States’ relationship with coastal topography is about to undergo a real reevaluation that will yield diverse results depending on the location. Miami’s population is unlikely to be absorbed by Vermont and New Hampshire, which have been identified as some of the safer areas from these particular climate stresses. However, the long-term demographic pressure is real, and depending on how the projections turn out, the choices being made now about where to place vital public facilities, where to issue mortgages, and where to build infrastructure may appear different in hindsight.