Scientists have officially declared Earth's third ever-major coral bleaching event.

Temperatures have been breaking record highs this year, causing widespread coral bleaching across Hawaii, the National Oceanic and Atmospheric Association (NOAA) reported. Scientists have now confirmed that the harmful phenomenon is spreading into the Caribbean, and may persist through the New Year. Coral bleaching occurs when corals are exposed to stress brought on by factors such as warmer ocean temperatures. The stress causes coral to expel symbiotic algae from their tissue, leading to the characteristic bleached white color.

"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."

Extensive coral bleaching can be lethal, and the destruction of these coral eliminates crucial habitats for marine life and shoreline protection. This most recent coral bleaching event originated in the north Pacific in summer 2014, and has since spread throughout the south Pacific and Indian oceans. The bleaching is hitting coral reefs disproportionately hard, and the NOAA estimates that by the end of 2015, close to 95 percent of U.S. coral reefs will have been exposed to ocean conditions that can lead to coral bleaching. Hawaii is currently experiencing the greatest risk, and bleaching in the region is predicted to continue to intensify this month. Areas such as "Haiti, the Dominican Republic and Puerto Rico, and from the U.S. Virgin Islands south into the Leeward and Windward islands" will also see an increased bleaching risk in coming weeks.  El Niño, is predicted cause bleaching in the Indian and southeastern Pacific Oceans after the new year, and potentially another global bleaching event 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."