Coastal erosion threatens Australian homes, roads, lifestyle

The pickets have stood through torrential storms, record-breaking king tides, pounding surf swells, and the ebb and flow of south coast NSW tourists and locals walking, fishing or surfing.

But in 2022 two of the stakes were swept out to sea when a storm carried away tonnes of sand from the beach.

Researchers from the Australian National University (ANU) started monitoring Bengello south of Batemans Bay in 1972, making it the longest continually monitored beach for coastal erosion in the southern hemisphere.

"The beach is at its lowest volume for at least 20 years at those two benchmarks," coastal geographer and project lead Dr Thomas Oliver said.

He has witnessed the "recurrence of an eroded profile over and over again" in recent years.

According to the federal climate change department, the sea is rising by seven centimetres per decade along the south-east coast of Australia, compared to the global average of about 3.5cm.

No time to recover

Dr Oliver said climate change affected beaches in two major ways: through sea level rise and increased frequency and intensity of storm events.

Beaches operate on a "sediment budget", he said.

Healthy beaches work in cycles in which storms carry away sand that is gradually replenished over time. Dr Oliver said a healthy beach had more inputs than outputs.

But the more intense storms along Australia's east coast in 2022 can break this cycle and put the beach in "sediment deficit", as happened in 1974 when the erosion was even worse.

"It doesn't have time to recover before the next storm hits," Dr Oliver said.

"Even though it's not the biggest storm we've ever had, it causes a lot of damage because the beach is already in a vulnerable condition."

While stakes were washed away at Bengello, in other parts of Australia residents fear their houses could be next.

Every king tide, the people of Illaroo Road at Lake Cathie on the NSW mid north coast worry they've seen their street for the last time.

Frustration reached new heights in April 2022 when a king tide washed away an entire section of beach.

Resident Vern Warner said erosion would only increase with more extreme weather events and he fears for infrastructure, safety and local lifestyle.

"The road will start to slip down onto the beach," he said.

Illaroo Road is just a small portion of the tens of thousands of kilometres of road and rail nationally threatened by rising sea levels.

The Climate Council estimates sea level rises could put more than $200 billion of Australian infrastructure at risk over the next century and ocean rises alone could wipe nine per cent from GDP per year.

In 2007 Port Macquarie-Hastings Council began work on a management plan for Lake Cathie, a small town of roughly 4200 people.

After seven years of deliberation the council decided a permanent rock wall was the answer to local coastal erosion.

It's since backed away from the plan in favour of natural remediation.

Approaches to coastal erosion vary wildly between local government areas.

At Stockton in Newcastle NSW, temporary mitigation measures such as seawalls and rock bags are used.

Long-term resident Christine Grainger has witnessed "huge changes" in the beach during her lifetime.

"Progressively we've noticed it has just been eaten away. It's tragic; it's sad. And access to the beach is so difficult," she said.

"One surf club Nippers day we noticed we had to go right down to the break wall, because there was no beach. It had just disappeared."

Now with her sixth grandchild on the way, the 67-year-old worries future generations will not be able to enjoy the beach the way she has.

Dr Hannah Power is a lead author of Life on the Edge: Adapting Coastal Management in a Changing Climate, a research paper drawing on 1000 responses from coastal geoscientists and engineers across Australia.

Dr Power said an overwhelming message from participants was the need for a national, consistent approach to coastal management.

Life on the Edge calls for a federal coastal resilience and adaptation office.

The agency would support state and local governments to coordinate approaches to coastal erosion through, for example, developing best practices, monitoring beach erosion and providing tools and analysis.

"There is no silver bullet," coastal geographer Dr Thomas Oliver said.

Authorities could "hold the line" or accept "managed retreat".

Holding the line, which is expensive but temporary, aims to keep the shoreline where it is through hard engineering - breakwalls and heavy infrastructure - or soft engineering - replenishing the beach with extra sand.

Managed retreat involves allowing the beach to withdraw but moving houses and infrastructure further from the shoreline.

"We are locked into a certain amount of sea level rise because of our emissions, so we do need to have a conversation about what we are going to do to adapt into the future," Dr Oliver said.

"There is no easy answer, but it needs to be local, state, federal and grassroots-scale because the solution to Bengello isn't going to be the right solution for Narrabeen."

I'm an avid outdoor enthusiast and spend my weekends camping, surfing, climbing, cycling or canyoning.

Climate change affects my ability to be able to do the things I love.

Beach erosion at my local break has deteriorated surf conditions, not to mention put houses and infrastructure at risk. Increased rainfall and storms has made the canyons I love inaccessible.

I am one of the lucky ones. Many people have already lost homes, livelihoods, loved ones - even hope - because of the effects of climate change.

This series touches on just some of the ways climate change is creeping into our lives.

We can't say we didn't know.

You can read the full Young and Regional: Our Climate Future series here.