Beaches are vanishing – and coastal cities may be next – Earth.com

Report on Global Beach Erosion and its Implications for Sustainable Development Goals

1.0 Introduction: A Threat to Coastal Sustainability

Coastal beach ecosystems are facing accelerated degradation due to climate change and anthropogenic pressures. This erosion poses a significant threat to environmental stability, economic prosperity, and community resilience, directly impacting the achievement of several United Nations Sustainable Development Goals (SDGs). Scientific evidence presented at the FAPESP Day Uruguay symposium underscores the urgent need for integrated action to mitigate the loss of these vital natural assets. This report synthesizes key findings on the drivers, dynamics, and consequences of beach erosion, framing them within the context of the SDGs.

2.0 Primary Drivers of Coastal Erosion

The primary forces driving the rapid loss of beaches worldwide are a combination of climate-related phenomena and unsustainable human development, challenging progress on SDG 13 (Climate Action) and SDG 11 (Sustainable Cities and Communities).

2.1 Climate Change Impacts (SDG 13)

• Sea-Level Rise: The progressive rise in sea levels pushes shorelines inland, permanently submerging low-lying beach areas.
• Increased Storm Intensity: More powerful wave action during storms removes sand from beach systems at an unsustainable rate, overwhelming their natural capacity for recovery.

2.2 Unsustainable Development (SDG 11 & SDG 15)

• Urban Encroachment: The construction of buildings, roads, and other infrastructure on or near dunes eliminates natural sand reservoirs and protective buffers, leaving coastal communities vulnerable.
• Interruption of Sediment Supply: Upstream dams on rivers trap sediment that would naturally replenish beaches, while coastal structures like seawalls and jetties block the lateral movement of sand along the coast. This disrupts the natural processes essential for maintaining life on land and below water (SDG 15, SDG 14).

3.0 Scientific Findings and Ecological Consequences

Recent research highlights the systemic nature of beach ecosystems and the cascading effects of their degradation. A study of 315 beaches worldwide found that one-fifth face intense or severe erosion. The ecological and economic consequences directly undermine SDG 14 (Life Below Water) and SDG 8 (Decent Work and Economic Growth).

3.1 Beach Morphodynamics and System Fragility

Beaches are dynamic systems composed of three interconnected zones: the dune, the beach face, and the submerged foreshore. These zones rely on a constant exchange of sediment to maintain equilibrium. Human and climate pressures disrupt this balance, leading to a systemic decline in resilience.

3.2 Impact on Biodiversity and Ecosystem Health (SDG 14)

A comprehensive study along the coast of Sao Paulo, Brazil, provided clear evidence of the ecological damage caused by human activity.

1. Reduced Species Richness: Heavy beach use, mechanical cleaning, and coastal construction were directly correlated with a significant reduction in species richness and biomass, particularly in the submerged foreshore.
2. System-Wide Stress Transfer: The research confirmed that impacts on the dry sand portion of a beach have detrimental effects on adjacent submerged marine zones, demonstrating how localized pressures cause widespread ecological harm.
3. Degradation of Marine Habitats: The loss of sandy shorelines eliminates critical habitats for a wide range of marine and terrestrial organisms, threatening coastal biodiversity.

3.3 Socio-Economic Impacts (SDG 8)

• Threats to Tourism: The narrowing and disappearance of sandy beaches jeopardize the tourism industry, a vital economic driver for many coastal communities.
• Impacts on Fisheries: The degradation of coastal ecosystems negatively affects local fisheries that depend on healthy near-shore habitats.
• Increased Community Vulnerability: The loss of natural coastal defenses like dunes exposes coastal towns to greater flood and storm damage, threatening infrastructure and livelihoods.

4.0 Recommendations for Action and International Cooperation

Addressing the crisis of beach erosion requires a coordinated, science-based approach grounded in international partnership, as called for by SDG 17 (Partnerships for the Goals). The symposium in Montevideo emphasized the need for regional cooperation among nations like Uruguay, Brazil, and Argentina, which share contiguous coastal systems.

4.1 Strategic Priorities for Sustainable Coastal Management

1. Implement Integrated Coastal Zone Management: Develop and enforce policies that regulate coastal development, protect natural dune systems, and ensure that infrastructure is resilient and sustainably sited, in line with SDG 11.
2. Advance Climate Action and Adaptation: Fulfill commitments under SDG 13 by reducing emissions and investing in nature-based solutions, such as dune restoration, to enhance coastal resilience to climate change.
3. Foster Regional and Scientific Partnerships (SDG 17): Strengthen collaborative research and data-sharing initiatives between countries to monitor coastal change and develop effective, large-scale management strategies.
4. Protect and Restore Coastal Ecosystems: Prioritize the conservation of marine and coastal biodiversity (SDG 14) through the establishment of marine protected areas and projects aimed at restoring natural sediment flows.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

• SDG 11: Sustainable Cities and Communities
• SDG 13: Climate Action
• SDG 14: Life Below Water
• SDG 15: Life on Land
• SDG 17: Partnerships for the Goals

2. What specific targets under those SDGs can be identified based on the article’s content?

• SDG 11: Sustainable Cities and Communities
  • Target 11.4: Strengthen efforts to protect and safeguard the world’s cultural and natural heritage. The article highlights how urban development, such as building over natural dunes, destroys the natural heritage of coastal ecosystems, which also serve as protective barriers for coastal towns.
  • Target 11.5: By 2030, significantly reduce the number of deaths and the number of people affected and substantially decrease the direct economic losses relative to global gross domestic product caused by disasters, including water-related disasters, with a focus on protecting the poor and people in vulnerable situations. The article explains that the loss of natural buffers like dunes exposes coastal towns to “stronger damage as the water moves inland” during storms, directly linking the degradation of these ecosystems to increased vulnerability to water-related disasters.
• SDG 13: Climate Action
  • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries. The article’s central theme is the erosion of beaches due to climate-related factors like rising sea levels. It emphasizes that protecting and maintaining natural beach systems, including dunes, is crucial for building resilience against climate impacts like stronger waves and storm surges.
• SDG 14: Life Below Water
  • Target 14.2: By 2020, sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including by strengthening their resilience, and take action for their restoration in order to achieve healthy and productive oceans. The article provides direct evidence of this, citing a study that found “heavy beach use reduced species richness and biomass, especially in submerged regions,” which are key components of coastal marine ecosystems.
• SDG 15: Life on Land
  • Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity and, by 2020, protect and prevent the extinction of threatened species. The article describes how “built areas replace natural dunes,” which is a direct example of the degradation of a critical terrestrial coastal habitat. This loss of habitat contributes to the overall loss of biodiversity in the coastal zone.
• SDG 17: Partnerships for the Goals
  • Target 17.16: Enhance the global partnership for sustainable development, complemented by multi-stakeholder partnerships that mobilize and share knowledge, expertise, technology and financial resources, to support the achievement of the sustainable development goals in all countries, in particular developing countries. The article explicitly calls for regional cooperation, stating that “Uruguay, Brazil, and Argentina share these coasts and must work together if they hope to protect them.” It also highlights the collaborative research between scientists from different institutions (e.g., Defeo and Brazilian collaborators) and the support from research foundations like FAPESP.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

• Rate of Beach Erosion/Loss: The article mentions that “Almost half of the beaches will disappear by the end of the century” and that a study found “One-fifth of the 315 sites faced intense or severe erosion.” Tracking the rate of beach erosion or the percentage of coastline lost would be a direct indicator of the severity of the problem and the effectiveness of protective measures (relevant to SDG 11 and 13).
• Species Richness and Biomass: The study cited in the article used “species richness and biomass” as metrics to measure the ecological health of the beaches. These are direct biological indicators that can be used to monitor the impact of human activities and the success of restoration efforts in coastal ecosystems (relevant to SDG 14).
• Abundance of Opportunistic Species: The article notes that the “abundance” of opportunistic species like polychaetes increased near cities due to organic material. This can be used as a negative indicator, where a decrease in the abundance of such species could signal an improvement in environmental quality (relevant to SDG 14).
• Extent of Natural Dune Systems: The article identifies the replacement of “natural dunes” with “built areas” as a key problem. Measuring the area of intact versus developed dune systems along a coastline would be a clear indicator of habitat degradation and vulnerability to coastal hazards (relevant to SDG 11, 13, and 15).

4. SDGs, Targets and Indicators Table

Source: earth.com