The impact of predicted sea level rises on coastal development on Australia's eastern seaboard has been exaggerated, a meteorologist says.
The NSW government this week said sea levels would rise by up to 40cm by 2050, while Prime Minister Kevin Rudd warned that 700,000 homes and businesses valued at up to $150 billion were at risk.
Historical analysis, however, shows that on average, global sea levels recorded a modest 20cm rise, or 1.7mm a year, throughout the 20th century, the Australian newspaper reports.
By comparison, the NSW government's projections equate to a future rise of about 6.6mm per year.
Meteorologist Bill Kininmonth believes only a thin layer of the ocean is actually warming - about 200mm - making it unlikely the oceans are expanding to any great degree.
"There's little reason to think the little bit of extra heat generated by greenhouse gases will make a dramatic difference," he said.
The NSW government's projections are based on global modelling by the Intergovernmental Panel on Climate Change and CSIRO regional analysis.
