Rising sea levels over the 21st Century will put many of Australia’s coastal cities and economic centres at risk of inundation (temporary or permanent ﬂooding).
The United Nations’ Intergovernmental Panel on Climate Change has adopted different Representative Concentration Pathways (RCPs) to model climate change, based on future greenhouse gas emissions levels. By the end of the century, the average sea level rise is projected to be between 0.3 m and 0.6 m in the lowest of the four scenarios (RCP 2.6), and by 0.6 m or more in the highest of the scenarios (RCP 8.5) and continue to rise for centuries.
Coastal erosion and inundation can damage residential, commercial and industrial property, as well as essential infrastructure. The average household costs of a ﬂood up to 1 m are between $60,000 and $80,000. The costs of larger and sustained ﬂooding leading to forced relocation would be greater. Rising sea levels also have signiﬁcant environmental consequences, such as coastal squeeze, where intertidal (seashore) habitats are disrupted and lost.
The initiative is for a proactive infrastructure strategy involving all levels of government. The strategy will need to consider which areas should be protected for continued use, modiﬁed to accommodate ﬂoods, or withdrawn from altogether.
Depending on these decisions, infrastructure options could include:
• nature-based methods
• buffer zones or physical barriers, such as seawalls to protect populations
• retreat and protect approaches
• infrastructure to facilitate early response to coastal hazard warnings and evacuations.
The strategy should also consider policy responses, such as actions to reduce exposure to coastal hazards, setting appropriate sea level rise benchmarks and planning controls for vulnerable areas.
Infrastructure Australia has received several submissions for localised coastal hazard issues. This initiative calls for higher-level program submissions that consider coastal hazards at a jurisdictional level.
Proponent(s) to be identified