It has long been famed as a subtropical paradise, with more than 400 different types of coral living beneath crystal clear waters in a far-flung corner of southern Japan.

Today, however, the future of Sekisei Lagoon – Japan’s largest coral reef – is in question after a new government report found that only one per cent of its coral is in a healthy condition due to global warming.

The decline of Sekisei Lagoon, which stretches over an expanse of more than 26 square miles in a remote area of southernmost Okinawa, is attributed to bleaching due to rising water temperatures and coral-eating starfish.

It is a process that has been evolving for decades, with the overall volume of coral in Sekisei Lagoon reportedly dropping by as much as 80 per cent since the late 1980s, after being badly hit by a string of mass bleaching incidents.

Bleaching occurs when unusually warm water causes coral to expel algae, leading to the coral turning completely white.