Climate change and rising sea levels are on track to wipe out almost half of the world's sandy beaches (49.5%) by 2100 which is almost 132,000 kilometres of coastline, according to a new study published in the journal Nature Climate Change.
The study used satellite images to track how beaches have changed over the last 30 years and carried out computer simulations to see how global warming could affect the coasts in the future. It also considered natural processes such as wave erosion and the underlying geology of a beach, as well as human factors, such as coastal building developments, dams... everything that can affect the health of a beach.
Even if humanity dramatically reduces the pollution caused by fossil fuels that cause global warming, more than a third of the planet's sandy coastlines could disappear as a result of climate-induced coastal flooding and human interference.
"What we found is that by the end of the century about half of the world's beaches will experience erosion of more than 100 meters," said Michalis Vousdoukas, co-author of the paper. "They are likely to be lost."
Sand erosion will endanger wildlife and could cause significant damage to coastal settlements that will no longer have buffer zones to serve as a protective shield against sea-level rise and storm surges. In addition, government measures to mitigate the damage are expected to become increasingly expensive and in some cases unsustainable.
Some countries will be more affected than others. Australia would be the first country on the list to be seriously affected by coastal erosion over the next 80 years. The study predicts that the coast of southern Australia could lose 12,324 km of coastline. Australia's iconic beaches, such as Gold Coast, Bondi and Manly, will be history. Canada will lose 9,577 km of beaches, Chile 5,471 km, Mexico 4,119 km, China 4,084 km, the United States 3,908 km, Argentina 3,668 km and Iran 3,654 km of beaches, according to the study.
You don't have to travel very far to see the harmful effects: in just 30 years, according to scientists at the European Commission's Joint Research Centre, erosion will have destroyed 36,097 km or 13.6% of the beaches. Researchers predict that the situation will worsen in the second half of the century, dragging another 95 061 km, more than 25% of the Earth's beaches.
Worst of all, this is not the worst-case scenario we could face. These are optimistic estimates, which rely on international action to combat climate collapse (CPR4.5) with global warming of about 3°C. In this scenario, the oceans will "barely" have increased by 50 centimetres by 2100.
What does it depend on if this changes?
The degree to which beaches are at risk depends on how much average global temperatures increase by 2100. Thus, the greater the temperature increase, the greater the sea level rise and the more violent the storms in some regions, causing more beaches to disappear beneath the waves.
Why are beaches important?
Beaches are valuable for fun or recreation, tourism and wildlife while providing a natural barrier that protects coastal communities from waves and storms.
Although beaches are dynamic environments, naturally changing with the tide and responding to changes in sea level, scientists say that when man includes development near water, he disrupts the ability of a beach to move and stops the natural processes that allow sand to replenish itself. Today, many of the beaches facing serious erosion problems are located in urbanized areas.
Reference: Sandy coastlines under threat of erosion, Nature Climate Change (2020). DOI: 10.1038/s41558-020-0697-0 , https://nature.com/articles/s41558-020-0697-0