Almost 60 years ago, nature forced some hard decisions on the Gold Coast.
A series of storms pummelled beaches over several months, climaxing in what media reported as a "cyclonic punch" in 1967 which laid bare the city's vulnerabilities.
An estimated 8 million cubic metres of sand was ripped from the beaches, double that of 2025's Cyclone Alfred, sparking a decades-long effort to build the city's renowned coastal protection system.
The underground 'A-line', a 5-metre-thick seawall made from boulders, shields high-rises and homes, sand pumps replenish beaches, while groynes, dunes and artificial reefs buffer tidal surges.
But rising seas have created a new set of hard decisions: how to build more homes in areas facing growing risks from climate change.
Hazard maps and housing
The Gold Coast City Council published updated maps this month highlighting areas at risk of natural hazards like landslides and storm tides.
That is on top of flood maps released in 2022 which put an additional 88,000 properties at risk of extreme floods.
A separate council report noted that climate modelling, including flooding and coastal storm-tide data, had not been consistently used to inform decisions on infrastructure and investment.
"Climate change is gradually increasing sea levels globally," the report stated, and was "expected to increase slow-onset coastal erosion".
Mayor Tom Tate said the report showed "some things the city has missed" but that climate risks would be factored into the council's new planning scheme "within 12 months".
But Cr Tate said proposed housing estates in the city's north, like Norwell, remained viable despite being mapped at "very high risk" of flooding, provided they include man-made water bodies.
"When it rains the water elements swell, but it doesn't swell to the extent that it floods houses," he said.
But Aysin Dedekorkut-Howes, Griffith University's program director of urban and environmental planning, said those northern suburbs were "basically estuarine".
"We keep building in those areas and we are putting people at risk," she said.
Changing perceptions of risk
Dr Dedekorkut-Howes said multiple studies identified the Gold Coast as "Australia's most vulnerable city in terms of economic cost from sea level rise".
"The A-line [is] the first and last line of defence," she said.
"Engineering can only help us so much. It can postpone some of the inevitable risks for 20, 30 years."
The Queensland government has projected an 0.8-metre sea level rise by 2100.
But Dr Aysin Dedekorkut-Howes said "that level is quite old", with other climate risk models projecting a 1.5-metre to 2-metre sea level rise.
"So if it's a one metre [rise] we are 20 centimetres short and more places will start getting nuisance flooding," she said.
"When it's rare, people feel it's an acceptable risk. But the way it's increasing with climate change means the events we used to think were rare are becoming more frequent."
Insurance woes on the horizon
Bond University's assistant professor of sustainable development, Ned Wales, said adapting to climate risks would add further pressure to the cost of housing.
"It's an economic risk. What really concerns me is the construction of properties in areas where the mapping, the flood risk and fire mapping has changed," he said.
"[There are] implications of damage to property, particularly for approvals that have happened in the last 20 years where older data may have been used rather than forecasting."
Dr Dedekorkut-Howes said canal housing estates were "highly vulnerable" because flooding during storms became more frequent as sea levels rose.
"It's very expensive and difficult to move them now, so there's entrenched development," she said
"There might come a point where insurance becomes unaffordable or not offered at all."
Climate and cost
Councillor Glenn Tozer said last week the council's new maps were designed to inform residents about the natural disaster risks their properties may face.
"Any insurance company that says council mapping has changed premiums is lying to you," he said.
A spokesperson for the Insurance Council of Australia said: "Insurers use a range of data sources to assess risk at an individual property level, including council flood and hazard mapping."
"Whether updated mapping has any impact on premiums will depend on whether it shows a material change in risk and whether that information is available to insurers," they said.
Cr Tozer also said the hazard mapping would have a "negligible, if none, effect on property values".
"Property values in our city are driven by supply and demand of housing stock, quality of life, proximity to schools, proximity to other infrastructure," he said.
But Dr Dedekorkut-Howes said the housing crisis was putting pressure on planners to build in areas facing growing climate risks.
"There are going to be areas in the future we need to move away from and that's not something that can be done overnight," she said.
"We need to plan so we don't build anything in really high risk areas."
