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Beaches aren't doomed, say scientists criticising 'alarmist' erosion claims

Waves hit the sea wall in Kingsand, Cornwall, in August - TOBY MELVILLE /REUTERS
Waves hit the sea wall in Kingsand, Cornwall, in August - TOBY MELVILLE /REUTERS

The world's beaches won't be lost to rising sea levels, scientists have said, criticising "incorrect and potentially damaging" claims that sandy coastlines face an existential threat.

A UK-led team pushed back against a scientific study published in March which claimed that almost half of the world's sandy beaches could be lost to the waves by the end of the century.

Co-author Gerd Masselink, professor of coastal geomorphology at Plymouth University, called the claims "alarmist" and said they distracted from the true threats to beaches worldwide.

"This thinking that all beaches are doomed regardless seems to divert the attention away from the fact that actually it's the coastal defences that jeopardise the existence of beaches," he said.

While long, unspoilt coastlines such as Australia's are unlikely to disappear because they can retreat, famous British beaches at Blackpool and Bournemouth are under threat because sea walls built to protect seaside communities stop the beach from migrating.

"As sea level rises, shoreline retreat must, and will, happen. Beaches, however, will survive. The biggest threat to the continued existence of beaches is coastal defence structures that limit their ability to migrate," the paper, published in Nature Climate Change, concludes.

The original study, led by Michalis Vousdoukas, an oceanographer at the European Commission, examined sandy beaches around the world, modelling sea level rises based on rising greenhouse gas emissions as well as existing geological trends and events such as storm surges.

It calculated the proportion of the world's sandy coastline that would retreat by 100m by 2100, concluding that between 36 and 50 per cent of beaches were under severe threat, and that several countries including the Gambia and Suriname could experience economic hardship because of their "fragile" economies.

Professor Masselink warned that unwarranted panic could prompt countries to invest in expensive and potentially ecologically damaging correctives pioneered in the Netherlands, which involve moving vast amounts of sand to shore up a beach.

More mindful building around coastal areas would be a better solution, leaving buffer zones between beaches and communities so seawalls and other coastal protection mechanisms are not necessary, he said.

"Over time any beaches that are currently in front of these structures will slowly disappear, they will slowly drown, unless big nourishment is replacing the sand that's lost," he said.

Waves crash against the sea wall in Swanage, Dorset earlier this month. Walls built to protect seaside developments prevent a beach from migrating inland  - Steve Parsons /PA
Waves crash against the sea wall in Swanage, Dorset earlier this month. Walls built to protect seaside developments prevent a beach from migrating inland - Steve Parsons /PA

In some places natural cliffs could lead to the same effect, though whether a beach is lost depends on the hardness of the rock in a cliff face, as softer cliffs can move back and provide sediment to shore up a threatened beach.

In the UK coastline can be designated a coastal change management area, where significant shoreline changes are expected over the next century and development must take this into account.

Sea levels have risen by eight to nine inches since the 1880s, with a third of that occurring in the past 25 years.

Rising seas are caused by melting glaciers and ice sheets and warming seawater, which expands as it rises in temperature. 

Some countries have seen beaches and coastal infrastructure crucial to their economies disappear at alarming rates, due to a combination of poor management and sea level rises.

The loss of natural defences such as coral reefs is causing greater damage, and there are fears that more frequent intense storms could also accelerate this trend.

Responding to the criticism of their work, Dr Vousdoukas and his co-authors argued that widespread human development at shorelines limited the ability of beaches to migrate, and warned that the "generic" claim that beaches will survive could lead to communities being "lulled into a false sense of security".

They criticised the paper for using "aggressive" language and added: "The use of such strong words in scientific literature needs to be justified by presenting for example results that are proven to be more accurate," something the new paper does not do.

"Our community is trying to deal with a climate crisis and we are doing our best we can to provide the most reliable predictions. In such a challenging task there is no correct and incorrect answer, model, or approach," Dr Vousdoukas added.