Research at Perranporth beach in Cornwall on rising sea levels

The extreme weather could in fact help build the beach by bringing sand from deeper waters or other areas, say scientists.

Storms are known to cause coastal erosion and, in some cases, serious damage to properties along the seafront.

But below the surface, they could be reinforcing the beach's defences, scientist have now found.

More extreme weather could therefore help protect coastal regions from rising sea-levels in the future.

Author Dr Mitchell Harley at the University of New South Wales said: "We know that extreme storms cause major coastal erosion and damage to beachfront properties.

"For the first time we looked not just above water, where the impacts of extreme storms are easy to see, but also deep down below it as well."

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Beaches along three coastlines in Australia, the United Kingdom and Mexico were examined by the researchers.

All had been subjected to extreme storms followed by a milder period, when the beaches were able to recover.

Researchers have been carrying out monthly topographic surveys on Perranporth beach in Cornwall since 2006.

The intertidal beach suffered "very significant losses" of sand after being battered by bad weather during the winters of 2013 and 2015.

But the total amount of sand, including underwater, had increased by 420,000 m3 by 2018.

Co-author Professor Gerd Masselink at the University of Plymouth said: "Looking at the extra sand gained by the beach at Perranporth, we are not quite sure whether this has come from offshore or from around the corner, or even both.

"However, we do now understand that extreme waves can potentially contribute positively to the overall sand budget, despite causing upper beach and dune erosion.

"We have previously shown that coral reef islands could naturally adapt to survive the impact of rising sea levels, and this study shows the changes to our own coastlines could mean the impact of extreme storms are not wholly negative.”

They also looked at Narrabeen beach in Sydney in the wake of a storm which ripped a swimming pool away from a beachfront property in 2016.

The damage caused at Narrabeen beach in Sydney in the wake of a 2016 storm Picture: UMSW Sydney/ SWNS

The amount of material deposited could offset decades of projected shoreline erosion, the researchers found after using high-resolution equipment to measure the beach and seabed.

How much sand could potentially be mobilised in the future via big storms is difficult to calculate because there are so few measurements of the seabed.

The results are based on observations from only a few beaches, but they could change the way people view the future of coastlines.

Dr Harley said: "What we found was that hundreds of thousands of cubic metres of sand was entering these beach systems during these events – that’s similar to the scale of what engineers use to nourish a beach artificially.

"This could potentially be enough to offset some of the impacts of sea-level rises caused by climate change, such as retreating coastlines, and by several decades in the long-term. It’s a new way of looking at extreme storms.”

The findings were published in Nature Communications Earth & Environment.