Scientists say that half of the world's sandy beaches could disappear by the end of the century if climate change continues unchecked, with Argentina tipped to me one of the most affected.
Researchers at the European Union's Joint Research Center in Ispra, Italy, used satellite images to track the way beaches have changed over the past 30 years and simulated how global warming might affect them in the future.
“What we find is that by the end of the century around half of the beaches in the world will experience erosion that is more than 100 meters," said Michalis Vousdoukas. "It's likely that they will be lost.”
The study, published Monday in the journal Nature Climate Change, found that the extent to which beaches are at risk depends on how much average global temperatures increase by the year 2100.
Greater temperature increases mean more sea level rise and more violent storms in some regions, causing more beaches to vanish beneath the waves.
“The projected shoreline changes will substantially impact the shape of the world’s coastline," more than a third of which is sandy beach, the authors wrote.
Even if humanity sharply reduces the fossil fuel pollution that drives global warming, more than a third of the planet's sandy shorelines could disappear by then, crippling coastal tourism in countries large and small, they reported in the journal.
"Apart from tourism, sandy beaches often act as the first line of defence from coastal storms and flooding, and without them impacts of extreme weather events will probably be higher," lead author Michalis Vousdoukas, a researcher at the European Commission's Joint Research Centre, told AFP.
"We have to prepare."
Some countries will be more affected than others, the researchers said.
Australia would be hardest-hit in terms of total beach coastline lost, with over 11,400 kilometres (7,080 miles) at risk. The 10 countries that stand to lose the most sandy shoreline also include Mexico, China, Russia, Argentina, India and Brazil.
Andres Payo, an expert on coastal hazards and resilience at the British Geological Survey, said that while the study's methods were sound, its claims should be treated with caution.
“There are many assumptions and generalisations that could change the outcome of the analysis both qualitatively and quantitatively,” said Payo, who wasn't involved in the study.
However, Vousdoukas said the amount of beach loss estimated by his team was in fact "a bit conservative” and could be higher.
The group considered two different warming scenarios — one in which average global temperatures rise by 2.4 degrees Celsius (4.3 Fahrenheit) by the end of the century and another that predicts an increase twice as high. The Paris climate accord's most ambitious target, of capping warming at 1.5 C, wasn't considered because scientists consider it unlikely to be achieved, Vousdoukas said.
The study's authors calculated that up to 40 percent of shoreline retreat could be prevented by reducing the greenhouse gas emissions that are driving climate change, but said that large and growing populations living along the coast will also need to be protected through other measures.
Citing the example of the Netherlands, which has battled the sea for centuries and even reclaimed substantial areas of low-lying land, the authors said “past experience has shown that effective site-specific coastal planning can mitigate beach erosion, eventually resulting in a stable coastline.”