NOAA scientists have declared the current widespread coral bleaching to be the third global coral bleaching event ever on record.
Besides the coral bleaching taking place across Hawaii caused by record warmer temperatures, coral bleaching has spread to the Caribbean, having originated from the Florida Keys and South Florida. As a result, the corals in Puerto Rico and the US Virgin Islands are under threat.
"The coral bleaching and disease, brought on by climate change and coupled with events like the current El Niño, are the largest and most pervasive threats to coral reefs around the world," said Mark Eakin, NOAA's Coral Reef Watch coordinator.
"As a result, we are losing huge areas of coral across the U.S., as well as internationally. What really has us concerned is this event has been going on for more than a year and our preliminary model projections indicate it's likely to last well into 2016."
This bleaching event, which began in the north Pacific in summer 2014 and expanded to the south Pacific and Indian oceans in 2015, is hitting U.S. coral reefs disproportionately hard. According to NOAA estimates, by the end of this year, almost 95 percent of U.S. coral reefs will have been exposed to ocean conditions that can cause corals bleaching.
The biggest risk right now is to the Hawaiian Islands, where bleaching is intensifying and is expected to continue for at least another month. Areas at risk in the Caribbean in coming weeks include Haiti, the Dominican Republic and Puerto Rico, and from the U.S. Virgin Islands south into the Leeward and Windward islands.
The next concern is the further impact of the El Niño, which climate models indicates will cause bleaching in the Indian and southeastern Pacific Oceans after the new year. This may cause bleaching to spread globally again in 2016.
"We need to act locally and think globally to address these bleaching events. Locally produced threats to coral, such as pollution from the land and unsustainable fishing practices, stress the health of corals and decrease the likelihood that corals can either resist bleaching, or recover from it," said Jennifer Koss, NOAA Coral Reef Conservation Program acting program manager.
"To solve the long-term, global problem, however, we need to better understand how to reduce the unnatural carbon dioxide levels that are the major driver of the warming," she added.
This announcement comes from the latest NOAA Coral Reef Watch satellite coral bleaching monitoring products, and was confirmed through reports from partner organisations with divers working on affected reefs, especially the XL Catlin Seaview Survey and ReefCheck.