Rising sea levels don’t mean the end of sandy beaches


Collaroy Services Club in June 2016. Credit: Professor Andrew Short

The Services Club in 2016 in Collaroy, which, unlike most Australian beaches, has developments along the coast that prevent the beach from retreating. Above: the beach near Wetherill Street. Credit: Professor Andrew Short

However, beaches backed by low coastal plains, shallow lagoons, salt flats and dunes, as is the case with most Australian beaches, will migrate to land due to rising sea levels. In these cases, the shoreline will recede, but the beaches are likely to remain, albeit a little raised in elevation and located towards the land, and certainly will not “die out”.

While beaches may not be commonly threatened in Australia, the same cannot be said for coastal homes. ‘In NSW, the hazard lines have been mapped for 2020, 2050 and 2100 on all beaches, so we know what to expect during extreme storm events with sea level rise,’ added Professor Short.

“These are reviewed every five years as more data becomes available and reviewed by the state government.”

Co-author Honorary Professor Andrew Short of the School of Geosciences at the Faculty of Science at the University of Sydney, who studied all 12,000 Australian beaches, said: “I found no evidence of widespread erosion, let alone accelerated erosion. of Australian beaches “.

He explained: “Since most have ‘room to move’, the vast majority should be able to slowly adapt and adapt to sea level rise, certainly up to 2100 and beyond.”

Coastal structures such as dikes prevent beaches from naturally adapting to sea level rise by migrating to land, and in such contexts, removal of structures (managed realignment) or nature-based solutions (e.g. sand replenishment) they may be the only ways to safeguard the future of these beaches. This is the case with Australian beaches such as Collaroy and Wamberal.

Andrew Cooper, professor of coastal studies at Ulster University and lead author of the new paper, said new methods are needed to predict the impacts of sea level rise on the coast: “This will require better coastal landform data sets. and a better understanding of shoreline response mechanisms in certain settings, ”he said.

“As the sea level rises, the retreat of the coast must and will happen, but the beaches will survive. The greatest threat to the continued existence of the beaches is the coastal defense structures that limit their ability to migrate. “


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