The current El Niño and global warming are prolonging the longest worldwide coral bleaching event to date, said scientists from the National Oceanic and Atmospheric Administration (NOAA) who are monitoring the event.

The NOAA scientists gave a forecast on the devastating coral loss due to heat stress and disease. The current coral bleaching event around the world started in mid-2014 in the western Pacific Ocean.

A report from this week's Oceans Sciences Meeting forecasted the event could extend into 2017. Last October, when El Niño further increased its wrath, NOAA scientists announced that a third worldwide coral bleaching event is also happening.

"This time we're in the longest coral bleaching event. We're maybe looking at a two- to two-and-a-half year-long event. Some areas have already seen bleaching two years in a row," said NOAA biological oceanographer Mark Eakin.

High ocean temperatures and other conditions cause stress to corals, which then lead to a bleaching event. The corals turn white when they excrete symbiotic algae found in their tissues.

These algae are the corals' food source. Without them, the corals become more susceptible to disease. Large corals die in severe coral bleaching incidents, leading to reef erosion, exposure of once-protected shorelines to destructive ocean waves and loss of fish habitat.

"On top of that, we've now added what is arguably the strongest El Niño on record," added Eakin, who is also NOAA's Coral Reef Watch coordinator.

The first widespread coral bleaching happened during the El Niño period in 1982 to 1983. Its first global incident was recorded in 1988 during another strong El Niño period. When La Niña followed right after, it brought the warm waters to places such as Micronesia and Palau.

The second global bleaching event happened in 2010. The El Niño during this time was less severe than the first two but it caused the same destruction to coral reefs nonetheless.

Eakin and his team will present the latest news and forecast for the worldwide coral bleaching event on Friday during the 2016 Ocean Sciences Meeting. The meeting is co-sponsored by the Oceanography Society, Association for the Sciences of Limnology and Oceanography and the American Geophysical Union.

Photo: Matt Kieffer | Flickr