Coastal hazards

NSW Coastal Erosion and Inundation Assessment 2025

Key Messages

  • Climate change is predominantly driving sea-level rise, thus increasing the potential of coastal hazard exposure and necessitating adaptation planning for NSW coastal communities.
  • The NSW Coastal Erosion and Inundation Assessment (2025) provides a comprehensive, state-wide update of coastal and estuarine hazard exposure now and into the future.
  • High-resolution seabed mapping, marine LiDAR, and advanced wave and tidal modelling have been integrated to project future changes in hazard-exposure specific to the NSW coastline and estuarine environments.
  • The assessment incorporates the full range of Intergovernmental Panel on Climate Change (IPCC) sea-level rise scenarios to capture potential future conditions.
  • Findings show that coastal and estuarine hazards will intensify over the coming decades, with increasing exposure of buildings, infrastructure, and heritage assets to erosion and inundation.
  • The results highlight the importance of proactive adaptation and risk-reduction measures to safeguard communities, infrastructure, and natural systems.
  • This assessment and its associated datasets support informed planning, adaptation and investment decisions across multiple time horizons, with data and mapping products available to assist state and regional adaptation planning. 

Context

Understanding sea-level change in NSW

Sea-level rise is one of the most direct and long-term consequences of climate change. It is primarily driven by the thermal expansion of seawater as it warms and by the melting of land-based ice from glaciers and ice sheets. 

The IPCC projects that global mean sea level will continue to rise for centuries, even under emissions reduction pathways. Rising sea levels are increasing the frequency, depth, and extent of coastal and estuarine inundation, as well as the occurrence and severity of coastal erosion across NSW, with impacts intensifying over time and under higher sea-level rise projections associated with high-emission pathways. 

This reinforces the importance of ongoing adaptation planning across NSW’s coastal and estuarine regions to prepare for the inevitable consequences of sea-level rise under a changing climate.

NSW Coastal Erosion and Inundation Assessment 2025

The NSW Coastal Erosion and Inundation Assessment (2025) examines coastal erosion, coastal overwash, and estuarine inundation hazards, as well as the associated exposure of built assets and cultural sites state-wide. It provides hazard-exposure information in a form suitable for decision-makers and regional planners to identify priority areas for adaptation and enhance community resilience to sea-level rise.

This assessment applies high-resolution seabed mapping, marine LiDAR, and advanced wave and tidal modelling to project future changes under a full range of IPCC sea-level rise scenarios, capturing potential conditions along NSW’s coast and estuaries. 

Key findings

Under all climate change scenarios, sea levels will continue to rise. Sea-level rise will intensify coastal erosion, coastal overwash, and estuarine inundation, with substantial and widespread impacts on coastal and estuarine communities, assets, and infrastructure.

Future projections

Coastal erosion is projected to increase progressively over time. On a state-wide basis, the results indicate that approximately 660 buildings are currently exposed to coastal erosion (for 1% annual exceedance probability). The exposure (at 1% exceedance probability) is projected to increase to around 910 – 960 buildings by 2050 and 2,460 – 4,530 buildings by 2100 under low (SSP1-2.6) to high (SSP3-7.0) emissions scenarios.

Coastal overwash and associated wave overtopping is likely to currently affect around 50 km of sandy coastline (at 1% exceedance probability), but the hazard is projected to increase to approximately 57–58 km by 2050 and 66–81 km by 2100 under low (SSP1-2.6) to high (SSP3-7.0) emissions scenarios.

Estuarine inundation is projected to expand as higher mean sea levels push tidal influence further upstream. Estuarine inundation currently affects over 2,700 buildings (at 3.6 days/year inundation frequency (1%)), with numbers projected to rise to approximately 5,320 – 6,260 by 2050 and 34,700–71,240 by 2100 under low (SSP1-2.6) to high (SSP3-7.0) emissions scenarios.

Note: Regarding buildings exposure, structures without an assigned address were excluded to reduce false positives, although secondary structures (e.g., sheds, water tanks, and carports) at locations with an assigned address remain in the dataset. Several building categories (e.g., residential, commercial) were considered; therefore, the building exposure results presented herein do not represent a single building class only. Further, only buildings projected to experience more than 5 m² of coastal erosion or estuarine inundation were included in the results presented herein.

Applications

The NSW Coastal Erosion and Inundation Assessment (2025) and associated datasets deliver a robust, consistent evidence base to inform planning controls and guide climate-resilient investment in NSW’s coastal communities. They enable coastal managers, regional planners, and infrastructure agencies to effectively plan and prioritise adaptation actions across different timeframes and emission scenarios.

For example, infrastructure managers can use the projections to assess the long-term exposure of key assets, such as roads and railway, to erosion and inundation, supporting decisions on maintenance schedules, resilience upgrades, or relocation planning. Planners may use the data to identify back-beach areas and low-lying land at increasing risk of overwash and inundation, helping refine zoning controls and development.

Estuary managers and local councils can apply the estuarine inundation projections to assess the vulnerability of buildings, transport corridors, and essential services in estuarine and coastal lake systems under different sea-level rise benchmarks. This information may guide early prioritisation of inundation mitigation works, green infrastructure investment, and nature-based adaptation solutions

By supporting risk-informed and place-based decision-making, the dataset enables communities and governments to plan proactively for short- to long-term coastal change and build climate resilience.

Users are encouraged to interpret the information in line with their local context, exposure profiles, and risk tolerance, ensuring that adaptation strategies remain both targeted and flexible over time.

View on a map

Marine hazards - NSW coastal erosion and estuarine inundation map 
 

Further reading and information

Linked Datasets