NOAA scientists warned that warm ocean temperatures in the tropical Pacific and Indian Oceans will take a toll on coral reefs across the globe.

The phenomenon could lead to devastating coral bleaching, leaving the reefs more prone to infection. The warning comes in the wake of severe bleaching seen in 2014, as well as the release of the most recent outlook from NOAA's Coral Reef Watch.

"The new outlook gives us greater confidence in what it shows for future coral bleaching and it comes at an important time," said Mark Eakin, NOAA Coral Reef Watch coordinator. "The outlook shows a pattern over the next four months that is similar to what we saw during global coral bleaching events in 1998 and 2010. We're really concerned that 2015 may bring the third global coral bleaching event."

Coral bleaching generally occurs when corals are stressed as a result of environmental changes. In this event, they release the symbiotic algae living in their tissues, causing them to turn white. Without these algae the coral loses its main food source and is more vulnerable to infection.

The NOAA identified the greatest threat to coral through May 2015 is in the western South Pacific and Indian oceans. Warmer waters have already caused significant bleaching in the Pacific, especially in regions such as Nauru, Kiribati and the Solomon Islands, and will most likely spread to Tuvalu, Samoa and American Samoa in the coming months. In the Indian Ocean, "thermal levels could also cause bleaching around Madagascar, Mauritius, Seychelles, and parts of Indonesia and western Australia."

"Climate change and its impacts, which can include bleaching, are some of the most pressing global threats to coral reef ecosystems today," said Jennifer Koss, acting program manager for NOAA's Coral Reef Conservation Program. "This suite of products is vital to help scientists, coral reef managers, and decision makers in the U.S. and around the globe prepare for bleaching events."