A new report says Sydney is particularly vulnerable to damage from rising sea levels. Photograph: Mick Tsikas/AAP
Rising sea levels are a “sleeping giant” issue that will put at risk coastal infrastructure worth up to $226bn, a new report has found.
Analysis by the Climate Council found Australia was likely to experience a sea level rise of 0.4m to 1m by the end of the century, with a “high end” scenario of 1.1m possible if the world warmed by about 4C compared with pre-industrial temperatures.
In this worst-case scenario, $226bn in property, including houses, schools, hospitals and ports, would be exposed to flooding and erosion, making much of it unviable.
The report says Sydney is “particularly vulnerable” to sea level rises, as flooding that now comes once every 100 years could occur every month.
South-east Queensland would suffer $2bn in damages from just a 0.2m sea level rise, while about 80% of Victoria’s coastline is vulnerable to higher sea levels.
Rising sea levels are caused by the melting of glaciers and polar ice caps as the planet warms. Thermal expansion, when the ocean expands due to warming, also contributes to a higher sea level. The global sea level is currently rising by an average of 3.2mm a year.
The Climate Council’s report warns that these seemingly small increases matter because they severely exacerbate extreme weather events, making coastal areas more vulnerable to storm surges and flooding. Just a 10cm sea level rise trebles the risk of coastal flooding.
Along with flooding, more than half of Australia’s coastline, about 31,000km, is vulnerable to recession, where the ocean eats away and degrades the coastline.
The advancing seas will cause problems for the tourism industry, the report predicts, with the Great Barrier Reef and Kakadu national parks put at risk. Sandy beaches such as those on the Gold Coast, in Tasmania and Perth could all suffer erosion.
Professor Will Steffen, a co-author of the report, said Australia’s sea level would depend on a number of factors.
“There are a range of projected sea level rises and 1.1m is on the highest end,” he told Guardian Australia. “There is concern about the west Antarctic ice sheet, which may not remain stable throughout the century, while Greenland is losing mass too.
“Put simply, if you’re an investor in infrastructure you’d expect to be around at the end of the century, get planning for a 1m sea level rise. There are quite a few cities where there will be a thousand-fold increase in one-in-a-century floods, which makes things unviable because you’ll be mopping up every month.”
Steffen said radical cuts in carbon emissions, along with a more integrated plan to secure coastal buildings, were required to deal with the looming problem.
“There is some good planning going on – for example the people building the new runway at Brisbane airport listened to the science and realised they are on low-lying land that’s prone to flooding,” he said. “They moved it up higher to minimise the risk.
“But a lot of councils are carrying the can and it’s hard for them when they don’t have supportive state and national governments.
“It appears we don’t have that support in Australia. If you look at the countries successful in getting emissions down, countries like the UK and Germany, they don’t have time for climate sceptics, they get on with the job of preparing their countries for climate change.
“It’s disappointing to see Australia moving backwards rather than joining that kind of movement.”