Coral reefs may not relate to people's daily lives, but their role in nature cannot be dismissed. They provide habitats for various types of animals and offer fishing and tourism resources. They also serve as natural embankments to protect land against big waves, including tsunami. However, the ecosystems that embrace coral reefs are under threat from the serious danger of coral bleaching — apparently due to rising sea water temperatures linked to climate change. The government and the public should realize that a key component of measures to protect coral reefs is the fight against global warming, and act accordingly.

According to the Environment Ministry, coral reefs from the Amami Islands of Kagoshima Prefecture to the Yaeyama Islands of Okinawa Prefecture suffered large-scale bleaching last summer. In the Sekisei lagoon lying between Ishigaki Island and Iriomote Island, both in Okinawa, more than 90 percent of the coral was found bleached, and 70 percent of the coral was found to be dead. The ministry says that the current situation affecting coral in the sea off southern Japan is the most serious since large-scale bleaching in 1998. High temperatures prevailed in seawater around the world in 1997 and 1998, killing 16 percent of reef-building coral worldwide.

As the extensive coral damage in the late 1990s shows, bleaching of coral reefs is a global phenomenon. The Environment Ministry cites the U.S. National Oceanic and Atmospheric Administration (NOAA) as saying that El Nino events — warming of surface waters and reduced upwelling of cold, nutrient-rich water off the western coast of South America — from 2015 to 2016 have caused unprecedented widespread and long-running coral bleaching, leading to the worst damage ever in the Great Barrier Reef of Australia and Kiribati in the central Pacific Ocean. This coral bleaching mentioned by NOAA continues to this day.