Coastal inundation protection strategy

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Sea level rise and flooding impacts
High Priority Initiative
Location
National
Geography
National
Category
Resilience
Problem/Opportunity timeframe
Longer term (10-15 years)
Proposed By
Infrastructure Australia identified initiative
Date added to the IPL
26 February 2020

Problem

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. The average sea level rise is projected to be between 0.4 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).

Sea inundation can damage residential, commercial and industrial property, and 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.

Proposed initiative

The initiative is for a proactive infrastructure strategy in advance of the inundation risks materialising. Involving engagement with 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strategy will need to consider which areas should be protected for continued use, modified to accommodate floods, or withdrawn from altogether.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 seawalls, buffer zones and other physical assets to protect populations, or infrastructure to facilitate early flood warnings and evacuations.

The strategy should also consider policy responses, such as actions to reduce greenhouse gas emissions and planning controls for vulnerable areas.

Next steps

Proponent(s) to be identified