Researchers say up to 60 percent of sandy beaches in Japan could disappear by the end of this century because of rising sea levels brought by global warming.
The group of scientists from Japan's National Institute for Environmental Studies and 27 other entities analyzed data from the 2014 report of the UN climate change panel and other sources.
They say that if the average global temperature rises by around 4 degrees Celsius, sea levels along the coasts of the Japanese archipelago could rise by up to 60 centimeters by the end of the 21st century.
74, or 96 percent, of Japan's 77 coastal areas could lose more than half of their beaches.
The group adds that sandy shores could completely disappear from 46, or some 60 percent, of the 77 areas.
The land and infrastructure ministry says the disappearance or reduction of sandy beaches has already occurred across Japan, due to industrial and urban development and high waves from typhoons. In the city of Chigasaki, south of Tokyo, the coastline receded by up to 50 meters over a period of roughly 50 years through 2005.
Experts say authorities should bolster countermeasures, taking into account the importance of beaches for tourism as well as disaster mitigation and the conservation of ecosystems.
The scientists used several hypotheses to make their estimates.
NHK created graphics based on the worst-case scenario.
A 100 percent loss is categorized as a "complete disappearance" and those of 81 to 99 percent as "close to disappearing." Losses of 51 to 80 percent are classified as a "substantial reduction" and those of 50 percent or less as a "reduction."
74 of the 77 coastal areas, or 96 percent of the total, are in the categories of a "complete disappearance," "close to disappearing," or a "substantial reduction."
Only 3 areas are in the "reduction" category.
The sandy areas that may completely disappear extend throughout Japan from the northern main island of Hokkaido through the southern prefecture of Okinawa, including Sagaminada near Tokyo and the Ogasawara Islands in the Pacific.