Australian coastal zones are likely to experience the full range of impacts from climate change and sea level rise. With over 80 % of the population living near the coast, this is likely to cause significant economic and social costs to Australia.

Impacts of rising sea levels, together with storm surge, are likely to cause inundation and accelerated erosion of many beaches around the Australian coast.

While sea-level rise will have far reaching effects in the mid to long term, there is a more imminent risk from short-term extreme storms. When higher seas (due to sea-level rise) combine with strong winds and wave action, there is an increased risk of inundation.

Inundation will eventually submerge low-lying coastal areas. This will lead to regular tidal flooding of communities and subsequently loss of land. Some properties will experience damage or become uninhabitable with some areas needing to be relocated with potential consequences such as cultural disruption and social and economic hardship.

Indigenous and built cultural heritage is being eroded, with historic buildings and archaeological sites damaged or lost due to flooding and shoreline retreat.

Inundation will lead to intrusion of salt water in soil and ground water. It will also lead to coastal squeeze with critical ecosystems such as mangrove and saltmarsh have less space to move as seas rise.

Inundation will also threaten significant industries and infrastructure. Coastal fisheries and aquaculture are likely to experience decline in productivity productivity due to warming oceans, shifting fish populations, and coral reef damage, impacting food security and traditional livelihoods.

Increasingly heavy rainfall events are likely to influence sediment delivery to the coast, which will influence coastal erosion. Land use change and extreme rainfall events also increases the load of contaminants in waterways.

More intense rainfall from inland or upper catchments can also be an additional flood risk as they work their way down through the catchment.

Additionally, freshwater flows into estuarine and coastal ecosystems play a critical role in supporting ecological health and productivity. These inputs deliver essential nutrients that enhance coastal productivity; however, they may also carry pollutants such as sediments and agricultural fertilizers, which can degrade water quality.

Heavy rain and local flooding will lead to damage to roads, buildings and urban drainage. especially during high tide and story events, which will place financial strain on council and other governments.

More extreme hot weather can have impacts on humans communities and especially for vulnerable populations.

Some coastal areas that experience rising temperatures and flooding will note declining health due to increased spread of waterborne diseases, aggravated respiratory issues, and other chronic illness due to heat. This will also have flow-on consequences for health systems.

Marine heatwaves an disrupt species’ life cycles, shift species distributions, and increase disease outbreaks, affecting both marine life and the industries that depend on it.

Marine heatwaves pose major risks to marine ecosystems, fisheries, aquaculture, and coastal livelihoods, particularly in Australia’s coastal and nearshore zones. Iconic ecosystems such as the Great Barrier Reef and Tasmania’s kelp forests are already experiencing damage - often severe - from recent marine heatwaves, leading to biodiversity loss and economic impacts.

Increased emissions of CO₂ to the atmosphere are partly absorbed by oceans. This has provided the benefit of slowing climate change, but has also changed the chemistry of ocean waters, increasing the acidity that in turn has negative impacts on marine organisms.

Coastal industries – such as shellfish aquaculture, fisheries, coral reef tourism, fisheries – may experience economic losses as populations of marine organisms are impacted.