Japan's Sekiseishoko coral reef, one of the country's largest reefs and popular diving destinations is at least 70 percent dead according to an Environment Ministry survey. It was found out that the corals were bleached due to warm waters.

Also, with the same survey, it was discovered that over 91 percent of the corals were partly bleached. Japan Times reported that "the survey was conducted at 35 points in Sekiseishoko, located between Ishigaki and Iriomote islands in Okinawa Prefecture, last November, and December."

Between June and September 2016, the ocean temperatures worsened when it was a degree or two Celsius higher than its normal of 30 degrees. The year 2016 became the third straight year to set a global heat record.

The World Meteorological Organization (WMO) said 'this year would be the warmest since records began in the late 19th-century, with average surface temperatures 1.2C above pre-industrial times.'

What is coral bleaching?

The National Oceanic and Atmospheric Administration defined coral bleaching as "When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white."

The site states that "When a coral bleaches, it is not dead." Corals can survive if water temperatures return to normal quickly. However, it proved to be fatal for the Sekiseishoko coral reef.

Will the temperature cool off?

Although that has yet to be seen this 2017, it seemed that Japan's case is lost. "Coral dies if it remains bleached for a long period," reports Japan Times.

Similarly last year, Australia's Great Barrier Reef also faced the same threat as coral continues to die six months after mass bleaching. Seven percent of the reef survived the heat wave but scientists said that more than half of the Great Barrier Reef was dead or dying.