World’s Sandy Shorelines have Increased Slightly but Erosion Poses Threat to Protected Marine Areas, Shows Study


July 20, 2018

A new study carried out by a team of researchers from the Netherlands suggests that world’s sandy shorelines have increased slightly in the past 30 years, but the size of protected marine areas has decreased due to eroding of about 24 percent of Earth’s sandy beaches, thereby posing a threat to plant and animal species.

In this study, the researchers used images captured by Landsat satellites from NASA and the U.S. Geological Survey. The team used the machine learning technique to “teach” their software how to accurately identify sandy beaches from the images. The software examined nearly 30 years of data (between 1984 and 2016) to find out how many of Earth’s beaches are sandy instead of rocky or icy, and how they have changed in the past three decades.

The analysis revealed that 31 percent of all ice-free shorelines are sandy or gravelly. The most number of sandy beaches (66 percent) are present in Africa, while Europe has the lowest (22 percent).

According to Arjen Luijendijk, a coastal development expert at Deltares, it took nearly two months’ calculation time to generate this data set of annual shorelines.

The study also revealed that many of the non-protected beaches are undergoing changes. About 27 percent of the world’s sandy beaches are growing, while 24 percent are eroding (16 percent of the sandy beaches are eroding at “intense” rates). Beaches in Africa and Australia are eroding more quickly than beaches in other continents.

The team now wants to expand the model to study seasonal variations in shorelines and to also analyze the coastal cliffs.

“Studying the behavior of sandy beaches at a global scale provides unique information on the universal causes and processes governing the retreat and accretion of coasts around the world,” Luijendijk said.

The detailed findings of the study are published in Nature.

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