Climate-driven flooding could cost Australia billions

Sea level rise due to climate change was exposing Australia’s coasts to a vastly increased risk of flooding that, if left unchecked, could cost the nation’s economy hundreds of billions of dollars, a new report has found.

The report, released on Wednesday by the Climate Council –  the independent, crowd-funded, NGO formed from the ashes of the Abbott-scrapped Climate Commission – explores two of the most serious consequences of rising sea level: a large increase in the frequency of coastal inundation and the recession of ‘soft’ shorelines.

Globally, it notes, sea levels have already risen and continue to rise due to climate change, as warming oceans increase the flow of ice from land to the sea. Australia, with the majority of its cities, towns and critical infrastructure located on the coast, was particularly at risk.

According to the report – Counting the Costs: Climate Change and Coastal Flooding – a sea-level rise of only half a metre would, on average, mean that 1-in-a-100 year flood events would occur every few months in Australia, while the nation’s sandy shorelines could retreat by 25-50 metres.

A sea level rise of 1.1 metre – a high end, but quite plausible scenario for 2100, says the report – would expose more than $226 billion in commercial, industrial, road and rail, and residential assets around Australian coasts to flooding and erosion hazards.

By 2050 – without adaptation – the losses from coastal flooding globally are projected to rise to $US1 trillion per year, says the report. By 2100, the losses from coastal flooding are projected to be 0.3–9.3 per cent of global GDP per year.

The high-end projection “is a scenario for global economic collapse.”

“Coastal flooding is a sleeping giant,” says the report. “If the threat of sea level rise is ignored, the projected increases in economic damage caused by coastal flooding are massive.”

Beyond the economic costs, there would be serious impacts on health and well-being, damage to coastal ecosystems and disruption of people’s lives – not to mention the large-scale displacement of coastal and island populations.

The report finds that a sea-level rise of 0.5-2 metres could displace between 1.2 and 2.2 million people from the Caribbean region and the Indian and Pacific Ocean islands, assuming no adaptation occurs.

The challenge, says the report, is to build effective approaches for dealing with the risks to existing infrastructure as well as making better decisions about future infrastructure development and action against climate change.

“In addition to a solid scientific knowledge base, perceptions, values, institutions, rules and other social factors are crucially important in developing appropriate responses to climate-related risks,” it says.

“An acceptance of the reality of climate change and its risks is essential, but much more is needed.

“Ultimately, stabilising the climate is necessary to reduce the level of risks from coastal flooding. Rapid and deep cuts in greenhouse gas emissions are critical here in Australia and around the world to stabilise the climate.”