By Phil Mercer
BBC News, Sydney
Perth's beaches are key to city life, but sea levels are rising fast
New figures have revealed that sea levels along the coast of Western Australia are rising at a rate double that of the world average.
Statistics from Australia's National Tidal Centre show levels have increased by 8.6mm a year off the coast of the state capital Perth.
That compares to a global average of just over 3mm.
Scientists have said that man-made climate change has played a significant role in the rise.
Climatologists have said that a combination of natural variability and man-made pollution have caused sea levels to rise around the world.
For much of the past century there were average increases of 1.7mm per year, while that rate doubled after 1993.
Some regions, however, have suffered more than others.
New figures show that the sea level rose off Perth in Western Australia and in the Kimberley region to the north by more than 8mm.
Dr John Church, from Australia's government-funded science and research body, the CSIRO, says these are worrying signs.
"Man's role is making a significant contribution to this global average rise," he said.
"I think the fact that sea levels are rising is a major reason for concern and it's a combination of the global average rise together with the natural variability leading to larger regional rises over certain periods and extreme events as in storm surges which will have the most impact
and, of course, sea level rise will not stop in 2100, it will continue for many centuries," he added.
About 80% of Australians live in coastal areas.
There are fears that vulnerable low-lying communities may have to be abandoned in years to come because of flooding and erosion.
CSIRO scientists have said that warming temperatures, which cause water to expand, have been a major trigger for sea-level rises in the 20th Century.
They have also blamed the melting of the world's icecaps and glaciers.