Coastal erosion

What Is Coastal Erosion?

Coastal erosion is the process by which natural forces, such as waves, currents, tides, and wind, wear away or move sediments, rocks, and landforms along coastlines. This ongoing geological phenomenon is influenced by various factors, including storm intensity, sea level rise, and human activities. From a financial perspective, coastal erosion falls under the umbrella of environmental economics and has significant implications for risk management, particularly concerning real estate assets, infrastructure, and regional economies. It represents a tangible environmental risk that can translate into considerable financial loss and necessitate substantial public and private investment in protective measures.

History and Origin

Coastal erosion has been a natural process throughout geological history, shaping coastlines over millennia. However, the intensity and impacts of coastal erosion have been exacerbated in modern times due to a combination of natural and human-induced factors. Historically, coastal communities adapted to shifting shorelines, but increased coastal development and static property rights have created fixed assets vulnerable to these dynamic processes.

A significant shift in approach to coastal management began to emerge in the late 20th and early 21st centuries. Organizations like the U.S. Army Corps of Engineers (USACE) have evolved their focus to include environmental protection and restoration alongside their traditional roles in navigation and flood control. The USACE's coastal management initiatives now encompass diverse strategies such as beach nourishment and wetland protection, recognizing the complex interplay of natural systems and human interventions¹³. Similarly, the European Union initiated projects like EUROSION in the early 2000s to develop policy recommendations for sustainable coastal erosion management across Europe, acknowledging that erosion, while a natural phenomenon, has become a growing concern due to climate change and past mismanagement¹².

Key Takeaways

• Coastal erosion is the natural process of coastline degradation by natural forces, intensified by human activity and climate change.
• It poses significant financial risks, including direct property loss, diminished asset valuation, and increased insurance costs for coastal properties.
• The economic impact extends to local economies reliant on tourism and coastal industries.
• Mitigation strategies range from engineered structures like seawalls to natural and nature-based solutions such as beach nourishment and wetland restoration.
• Effective coastal management requires a long-term, integrated approach involving local, national, and international collaboration.

Interpreting Coastal Erosion

Interpreting coastal erosion involves understanding its rate, its potential impacts, and the various strategies for managing it. The rate of erosion, often measured in meters or feet per year, can vary significantly depending on local geology, wave energy, tidal range, and the presence of protective features. For instance, some barrier islands in the U.S. Southeast can experience average coastline recession rates of 25 feet per year, while severe storms can remove substantial dunes in a single event¹¹.

Assessing the implications of coastal erosion involves evaluating both immediate and long-term consequences. Immediate concerns include the physical damage or loss of existing structures and land. Over the long term, sustained erosion can lead to changes in land use planning, affecting future investment and development. Professionals in urban planning, real estate, and risk management utilize erosion data to inform decisions on zoning, building codes, and insurance premiums, aiming to promote more resilient coastal communities.

Hypothetical Example

Consider "Oceanview Heights," a hypothetical coastal residential development. Initially, homes are built 100 feet from the shoreline. Due to increasing storm frequency and intensity, and a gradual rise in sea levels, the coastline begins to recede at an average rate of 2 feet per year.

After 20 years, the shoreline has moved 40 feet inland, bringing it within 60 feet of the original homes. This sustained coastal erosion begins to impact property values as the risk of future damage increases. Homeowners face higher insurance premiums, and some insurers may even withdraw coverage. The community might consider implementing a beach nourishment program, a "soft" erosion control method that involves adding sand to the beach. This project, however, would be expensive, requiring significant capital. If the erosion continues unchecked, properties could eventually become uninhabitable, leading to substantial financial losses for homeowners and a decline in the local tax base, demonstrating the direct economic impact of the phenomenon.

Practical Applications

Coastal erosion has critical practical applications across various sectors, particularly in finance, urban planning, and environmental policy.

• Insurance and Risk Assessment: For the insurance industry, coastal erosion is a significant factor in underwriting policies for properties in coastal zones. Insurers use erosion rates, sea level rise projections, and storm frequency data to assess risk and determine premiums. As erosion accelerates, the availability and affordability of coastal property insurance can diminish, impacting market volatility in these areas.
• Real Estate Development and Asset Valuation: Developers and investors in coastal real estate must factor in erosion risks, which can significantly affect property values and long-term viability. Disclosure requirements regarding erosion hazards are becoming more stringent, influencing buyer decisions and investment appraisals.
• Infrastructure Planning: Governments and private entities must consider coastal erosion when planning and maintaining critical infrastructure such as roads, bridges, utilities, and ports. This often necessitates substantial public policy initiatives and funding for protective measures or planned relocation. The U.S. Army Corps of Engineers, for example, is a key federal agency involved in safeguarding communities and infrastructure from flooding and coastal storms through various management activities¹⁰.
• Economic Impact on Tourism and Fisheries: Coastal erosion threatens industries reliant on healthy coastlines, such as tourism and fishing. The loss of beaches, habitats, and access points can lead to reduced revenue and job losses. For instance, coastal erosion costs the United States approximately $500 million annually in coastal property loss⁹. This also impacts associated sectors, including the supply chain for coastal businesses. The National Oceanic and Atmospheric Administration (NOAA) makes significant investments in coastal management and habitat restoration, which are projected to stimulate economic activity and job creation in coastal communities⁸. In Chile, scientists warn that coastal erosion could erase ten beaches within a decade, transferring significant costs to fishing and tourism sectors⁷.

Limitations and Criticisms

While efforts to manage coastal erosion are extensive, they face several limitations and criticisms. A primary concern is the cost and long-term effectiveness of many interventions. For example, beach nourishment projects, while common, are expensive and often temporary, as newly added sand can be washed away by subsequent storms. The U.S. government spends an average of $150 million annually on beach nourishment and other shoreline erosion control measures⁶.

Another criticism revolves around the environmental impact of certain "hard" erosion control methods, such as seawalls and jetties. These structures can disrupt natural sediment transport, leading to erosion in adjacent areas or the loss of beach habitat⁵. A balanced approach that considers ecological consequences is often advocated, moving towards more "living shoreline" solutions that utilize natural elements like vegetation and wetlands.

Furthermore, the issue of "coastal squeeze" arises when human development or protective structures prevent natural shoreline migration, leading to the loss of intertidal habitats as sea level rise pushes water further inland⁴. This can have detrimental effects on coastal ecosystems and biodiversity³. Critics also highlight the challenge of coordinating management efforts across different jurisdictions and the potential for fragmented responses that fail to address the systemic nature of coastal erosion. Integrated coastal zone management, which considers the broader interactions within a coastal system, is often seen as a more sustainable development approach.

Coastal Erosion vs. Sea Level Rise

Coastal erosion and sea level rise are distinct but closely interconnected phenomena that impact coastal areas.

Coastal erosion refers to the physical wearing away and removal of coastal land and sediments by dynamic forces like waves, currents, and wind. It's a process of horizontal land loss that can be highly localized and influenced by immediate weather events, such as storms. While natural, human activities like coastal development and altered sediment supply can accelerate it.

Sea level rise, on the other hand, is the long-term increase in the average global sea level, primarily driven by thermal expansion of ocean water and the melting of glaciers and ice sheets due to climate change. It is a vertical change in the ocean's surface that increases the frequency and intensity of coastal flooding and amplifies the effects of coastal erosion by allowing waves to reach further inland and exert more force on the shoreline.

The confusion between the two often arises because sea level rise is a major driver of accelerated coastal erosion. A higher baseline sea level means that storm surges penetrate further inland, and normal tides can reach areas previously unaffected, intensifying erosive forces. Therefore, while not the same, addressing coastal erosion often requires considering the projections and impacts of sea level rise as a fundamental contributing factor.

FAQs

What causes coastal erosion?

Coastal erosion is caused by both natural processes and human activities. Natural factors include wave action, tides, currents, storms, and geological shifts. Human activities that contribute to erosion often involve coastal development, dredging, and the construction of structures like dams that reduce the natural supply of sediment to beaches².

How does coastal erosion affect property values?

Coastal erosion can significantly decrease real estate property values by increasing the risk of physical damage or loss of land. This heightened risk can lead to higher insurance premiums, reduced market demand, and in severe cases, the complete loss of structures, making properties unsellable or uninhabitable¹.

Can coastal erosion be stopped?

Completely stopping coastal erosion is generally not feasible, as it is a natural and ongoing process. However, its impacts can be managed and mitigated through various strategies. These include "hard" structural defenses like seawalls and groins, "soft" solutions such as beach nourishment and dune restoration, and non-structural approaches like setback regulations and relocation of vulnerable assets. The goal of risk management is often to adapt to and minimize the negative consequences of erosion.