Climate change has become one of the most pressing issues affecting our planet today. Its impacts are especially pronounced along coastlines, where rising sea levels and increased storm activity threaten communities and ecosystems alike. As a result, coastal surveying and monitoring efforts have become more critical than ever to understand and respond to these changes effectively.

The Growing Urgency of Coastal Monitoring

Coastal areas are dynamic environments, constantly reshaped by waves, tides, currents, and human activity. But the accelerating pace of climate change is driving changes that far exceed natural variability. Global mean sea level has risen about 8–9 inches since 1880, with the rate of rise accelerating in recent decades, according to NASA’s sea level data. For low-lying coastal zones, even a few inches of rise can amplify erosion, storm surge flooding, and saltwater intrusion into freshwater aquifers.

Coastal surveying—the process of measuring and mapping the physical features of shorelines—has long been a foundational tool for navigation, land-use planning, and hazard mitigation. Today, these surveys serve a more urgent purpose: tracking the rate of shoreline retreat, sediment loss, and ecosystem transition in near real-time. Without accurate, repeated surveys, it becomes impossible to model future scenarios or design effective adaptation strategies.

How Climate Change Alters Baseline Conditions

Climate change fundamentally alters the baselines against which coastal change is measured. Traditionally, surveyors relied on fixed reference marks—such as benchmarks tied to tidal datums—to establish consistent vertical and horizontal control over decades. But rising seas are submerging these marks at an alarming rate. In many regions, originally dry benchmarks are now periodically inundated, complicating repeat surveys and introducing error.

Furthermore, the composition of coastlines is changing. Warmer oceans intensify the power of storms, leading to more frequent and severe erosion events. The USGS Coastal Change Hazards Portal documents how barrier islands, sandy beaches, and even rocky cliffs are retreating at rates that outpace historical averages. This shifting baseline forces surveyors to recalibrate their methods and adopt more flexible, frequently updated reference networks.

Sea Level Rise and Tidal Datum Shifts

One of the most significant challenges is the shifting of tidal datums—mean lower low water, mean sea level, and mean higher high water. These are the reference surfaces for nautical charts, coastal boundary delineation, and floodplain mapping. As sea level rises, so do these datums, which means that property lines defined by “mean high water” change over time. Surveyors must now consider dynamic, time-varying datums rather than static ones. This adds complexity to legal surveys and boundary disputes, especially in areas with rapid subsidence or accretion.

Increased Sediment and Nutrient Loads

More intense rainfall events—another hallmark of climate change—flush increased loads of sediment, nutrients, and pollutants into coastal waters. This alters the morphology of deltas, estuaries, and tidal channels. Dredging operations and navigational surveys must adapt to rapidly shifting shoals and channels. In the Gulf Coast, for example, the combination of sea level rise, subsidence, and altered sediment supply has resulted in some of the highest erosion rates in the United States. The Louisiana Coastal Protection and Restoration Authority conducts hundreds of detailed surveys each year just to keep maps current.

Surveying Challenges in a Changing Climate

Climate change complicates coastal surveying in several interrelated ways:

  • Submergence of survey marks. Permanent benchmarks placed decades ago are being lost to high tide lines and inundation. This forces reliance on less stable, temporary markers or modern GNSS-based control networks that require careful vertical correction.
  • Increased erosion rates. Shorelines that historically retreated inches per year are now retreating feet per year in many locations. Survey intervals that sufficed in the past are now inadequate to capture rapid change.
  • Storm damage to infrastructure. Hurricanes and winter storms destroy survey monuments, tide gauges, and coastal monitoring stations. For example, Hurricane Michael (2018) wiped out several permanent GPS stations along the Florida Panhandle, creating gaps in the record precisely when data was most needed.
  • Accessibility and safety concerns. Flooded or unstable coastlines hinder access for survey teams and equipment deployment. Marsh and swamp environments become treacherous with rising water, and survey vessels must navigate shallower, debris-filled waters after storms.
  • Measurement error amplification. Traditional survey techniques assume stable, dry conditions. When benchmarks move or go underwater, error budgets increase. The combination of rapidly changing topography and uncertain vertical references can degrade the accuracy needed for engineering design and regulatory compliance.

In many jurisdictions, coastal property boundaries depend on the location of the high-water mark or mean high tide line. As that line moves landward, property boundaries shift. This creates legal disputes and requires surveys that can establish historical and current positions with high precision. Surveyors must also consider the possibility of “avulsion”—a sudden change from storm events—versus “accretion” or “erosion” that is gradual. The legal treatment differs, and surveyors need to provide evidence to support boundary adjudication.

Technological Innovations Driving Resilience

To address these challenges, scientists and surveyors are adopting a suite of advanced technologies that enable more frequent, accurate, and cost-effective coastal monitoring:

  • Satellite imaging and remote sensing. Missions like the Sentinel constellation (ESA) and Landsat (NASA/USGS) provide regular, synoptic views of coastlines. Sentinel-1’s synthetic aperture radar can image through clouds and darkness, essential for monitoring after storms. These data allow detection of shoreline change on a global scale.
  • Uncrewed aerial systems (drones). Drones equipped with high-resolution cameras and RTK GPS can produce centimeter-level orthomosaics and digital elevation models. They are ideal for rapidly surveying areas that are dangerous or inaccessible on foot. A single coastal survey mission can now cover miles of beach in hours.
  • LIDAR bathymetry and topography. Airborne LIDAR (Light Detection and Ranging) uses laser pulses that can penetrate shallow water to map the seafloor as well as the adjacent upland. This seamless topobathymetric data is essential for modeling coastal flooding and sediment transport. NOAA’s Digital Coast provides free access to such datasets.
  • Automated in-situ sensors. Networks of pressure transducers, acoustic Doppler current profilers, and water quality sondes now provide continuous, real-time data. They are deployed on fixed platforms (pilings, buoys) and sometimes on autonomous surface vehicles. These sensors fill the temporal gaps between surveys.
  • Continuously operating reference stations (CORS). GNSS base stations that stream data allow surveyors to correct for vertical and horizontal movements of the Earth’s crust, including subsidence and tectonic motion. This is critical for establishing stable reference frames over time.
  • Machine learning and AI. Automated algorithms now analyze satellite and drone imagery to extract shorelines, classify habitats, and detect changes without manual digitization. This speeds up the processing of large data volumes and reduces human error.

Integration of Multi-Source Data

No single technology provides a complete picture. The most effective coastal monitoring systems combine satellite imagery, airborne surveys, in-situ sensors, and ground truthing into coherent data management platforms. These systems allow for near-real-time products, such as erosion rate maps or flood inundation forecasts, that serve emergency managers and planners. For instance, NOAA’s National Centers for Environmental Information host archives of coastal data that are used to refine models for sea level rise scenarios.

Integrating Data for Better Decision-Making

Collecting data is only half the battle. The true value lies in translating survey measurements into actionable insights. This requires robust data integration, standardized quality control, and accessible dissemination tools. Government agencies, academic institutions, and private firms are collaborating to create data portals that serve both scientists and the public.

Case Study: The Gulf Coast

The northern Gulf of Mexico is experiencing some of the highest rates of relative sea level rise in the continental US, due to a combination of eustatic rise and land subsidence. In response, the Louisiana Coastal Protection and Restoration Authority (CPRA) conducts annual topobathymetric surveys of hundreds of miles of coastline. These surveys feed into numerical models that guide billions of dollars in restoration projects—from barrier island restoration to marsh creation. Without repeated, high-precision surveys, the effectiveness of these projects could not be measured.

International Coordination

Climate change knows no borders, and coastal monitoring efforts are increasingly coordinated at the international level. The Global Sea Level Observing System (GLOSS) and the Group on Earth Observations (GEO) encourage consistent methodologies for tide gauges, satellite altimetry validation, and shoreline mapping. These networks ensure that data from different nations can be compared and combined, essential for understanding global patterns.

Looking Ahead: The Path Forward

The challenges posed by climate change to coastal surveying are formidable, but they are not insurmountable. Continued investment in technology, training, and data infrastructure will be vital. Several trends are likely to shape the future:

  • Increased use of autonomous platforms. Uncrewed surface vessels and gliders can perform long-duration surveys at lower cost and with less human exposure to hazardous conditions.
  • Better vertical reference systems. Geoid models and time-dependent datums are being developed to account for ongoing sea level rise, making it possible to predict where benchmark adjustments are needed.
  • Public-private partnerships. Crowdsourced data from recreational boats and fishing vessels, combined with institutional monitoring, can fill gaps in coverage, especially in remote or data-sparse areas.
  • Community engagement. Local knowledge and citizen science initiatives can augment technical surveys, providing historical context and ground-truth for satellite products.

The urgency of climate change demands that we monitor our coastlines with greater frequency and accuracy than ever before. Each survey, each sensor deployment, and each data set brings us closer to understanding the pace of change and identifying effective responses. By embracing innovation and fostering collaboration across sectors, the coastal surveying community can rise to meet the challenge—protecting both natural ecosystems and the communities that depend on them.

As sea levels continue to rise and storms grow more intense, the need for robust, adaptive monitoring systems will only intensify. Investing in these efforts today is not just a matter of scientific curiosity; it is an essential component of resilience planning for a warming world.