Risks to coastal natural environment
The response of Australian coastal ecosystems and landforms to climate change will vary but are expected to involve shoreline recession, vertical accretion, increased saline inundation of wetlands, and the modification and southward shift of habitat. 'Coastal squeeze' could occur in southern Australia where obstacles such as roads or settlements prevent the landward migration of some ecosystems, such as saltmarshes.
The coastal systems most at risk are estuaries and associated wetlands, coral reefs, constrained tidal flat communities and beaches where there is a lack of sediment replenishment. Not all of the ecosystems at risk will be on the coast. Estuaries, rivers, lakes and lagoons susceptible to the impacts of sea level rise may be some distance inland. Importantly, there are a number of nationally and globally significant coastal environments at risk from climate change, which could also lead to the reduction of habitat for some migratory bird species.
Climate change impacts, particularly on top of other stresses, could shift coastal systems past thresholds or tipping points beyond which the landforms or ecosystem no longer function in the same way. The reduction of non-climate stresses on coastal ecosystems can play an important role in increasing resilience to the impacts of climate change.