Scientist warns of threat to Ocean Beach

Global warming may have adverse affects on the Peninsula, according to geoscientist Mr Peter Cowell from the University of Sydney's Institute of Marine Science.

Mr Cowell has recently developed models to display how far beaches may recede due to global warming.

Mr Cowell's mid-range modelling was recently reported in the Sun Herald, where it was stated that "the surf beach at Manly could recede by 34 metres by 2050 and 85 metres by 2100" with a worst case scenario that would result in the surf beach being eroded by 150 metres and the harbour beach receding 30 metres.

The article also pointed out that at Palm Beach, mid range modelling showed the beach could recede by 50 metres by 2050 and 125 metres by 2100, with a worst case scenario would result in the Palm Beach Peninsula disappearing as the beaches on either side recede by 220 metres.

At Bondi, the worst case scenario would result in the beach pushed back 90 metres by 2100 and, at Maroubra, the beach could go back 105 metres, according to the article.

Mr Cowell said he knew Ocean Beach quite well.

"I haven't done any modelling for Ocean Beach but, from general principles, predictions there would be worse than most places along the Sydney and Central Coast," Mr Cowell said.

Mr Cowell said that this was because the sea bed offshore was of unusually low gradient, and this is what affects beach response to sea level rise.

"That is, the threat is much greater at Ocean Beach than at Palm Beach," Mr Cowell said.

"The inland side of the Woy Woy plain is also subject to shoreline retreat due to sea level rise."

Lyle Stone, Peter Cowell, September 28 The Sun Herald, August 21