Local icons that are within a cooee of the beach could be lost to rising sea levels. Rising water levels also may threaten nationally significant heritage areas. For example, many Aboriginal middens may just disappear beneath the ocean.

For each centimetre of sea-level rise, the land is eroded by tens of centimetres. With more storms, and more people living at the coast, the amount of property – not to mention lives – at risk of coastal flooding will increase.

Of course, sea levels rise and fall with the tide, and with the centuries. But lately they’ve been rising faster than they have for generations.

20 000 years ago, the ocean surface was more than 120 m lower than today. Then, as the world emerged from the last ice age, sea level rose by a metre per century for many millennia, and sometimes faster than 4 metres per century.

Sea level rose at an average rate of about 1.6 mm per year over the 20th century. ‘This is already an order of magnitude larger than the rate of rise over previous millennia,’ says CSIRO’s Dr John Church. ‘Since the early 1990s there has been a further increase in sea level to around 3.2 mm per year – about twice the average rate of rise over the 20th century.’

The amount of sea-level rise depends on where around the coast you are, with variations due to ocean currents, the shape of the coast, and the gradient of the land. If you’re in the south or east of Australia, rates of sea-level rise are similar to the global average. But if you’re in the north, sea levels are rising more rapidly mainly due to natural variability.

What icons in your community could be lost to sea-level rise?
What plans – if any – do you have in place to protect them?

More info: http://www.cmar.csiro.au/sealevel