When you spend enough time on any beach, you begin to notice things. The way the tide pulls its fingers across the sand. The odd little berms that remain after a storm. Once leading down to dunes, the wooden stairs at the end of a boardwalk now descend awkwardly into open water. It’s difficult to ignore the shifting boundary between land and sea. It is also moving in a single direction nearly all the time.
It’s becoming more difficult to ignore the numbers. In the US, coastal erosion destroys about $500 million worth of property annually, and the federal government spends an additional $150 million or so attempting to prevent it. The majority of beach nourishment comes from trucks and dredges that transport tons of sand and dump it onto eroding shorelines like sugar on a wound. It holds occasionally. Sometimes it’s all gone by Monday morning after just one nor’easter. Speaking with those who study this professionally gives me the impression that we’ve been battling the ocean with a checkbook for a very long time without truly knowing what we’re up against.
This is where nearshore oceanography comes into play, and it’s a more subdued field than you might think for one that carries so much weight. These scientists investigate what occurs in the surf zone, which is the narrow, turbulent stretch of water between the breakers and the dry sand. Here, waves change, sediment shifts, and minute variations in current can determine whether a beach survives or dies. The type of work done with PVC poles and dye tracers was a backwater discipline for decades. Drones, satellites, and machine learning models that have been trained on years’ worth of wave data are now being used. It has a genuine urgency that didn’t exist even ten years ago.
The size of the issue that is emerging is one of the causes. Even under optimistic climate scenarios, nearly half of the world’s sandy beaches may drastically recede by 2100, according to a study released by the Joint Research Center of the European Commission. In thirty years, over 22,000 miles, or 13.6% of all sandy coastlines, may disappear. These are the optimistic figures as well. The careful figures. Those who believe that the world truly gets its act together on emissions, which seems like a generous assumption given the events of the last few climate summits.
The outdated responses are also not holding up well. For the majority of the 20th century, riprap, levees, seawalls, and groins were used to harden a disappearing shoreline. Saltwater versus concrete. Hard structures frequently just push the issue down the beach, as we have discovered—sometimes painfully. The neighbor two miles down the coast inherits your erosion problem as sand starves on one side and scours away on the other. Cost is another issue, and when these structures fail at all, they do so at a high cost. Similar to how doctors discuss therapies that were effective in the 1970s, coastal engineers now discuss them with a kind of weary diplomacy.
Dune restoration, living shorelines, oyster reefs, and marsh buffers are examples of what is sometimes referred to as “green infrastructure.” items that bend rather than shatter. By simulating how a restored dune will behave when the next Category 3 occurs, nearshore oceanographers are increasingly informing planners where these projects might actually be successful. It’s a flawed science. Models are inaccurate. People are surprised by storms. However, compared to the discussion we were having when we believed concrete could hold the line indefinitely, this one is more candid.
The question that no one really wants to answer is whether any of it will be sufficient. As the Arctic stays open water longer and permafrost thaws, Drew Point, Alaska, loses portions of itself every summer. Every 100 minutes, Louisiana loses the equivalent of a football field. The Great Lakes coasts recede by 50 feet annually, while the Southeast’s barrier islands recede by 25 feet in some areas. As you watch this happen, you begin to question whether the true task of nearshore oceanography in the ensuing decades will be to carefully determine which beaches we can still save rather than to save beaches.
