Some 2,500 scientists, policymakers and managers came together in Honolulu in June 2016 for the world's largest summit dedicated to the future of coral reefs. With coral reefs threatened by global warming, participants at the 13th International Coral Reef Symposium are calling for a joint rescue effort.

The event gathered guests from 97 countries, including the presidents of Palau, Micronesia, and the Marshall Islands. Coral reefs are a key source of income in those countries, mostly through tourism.

The Pacific nations are worried about the future of their tourist hotspots, as coral reefs face so-called "bleaching" due to rising sea temperatures. "If our coral reefs are further degraded, then our reef-dependent communities will suffer and be displaced," leaders of Palau, Micronesia, and the Marshall Islands said in an open letter.

Bleaching happens when coral is stressed by hot ocean waters or other changes in the environment. In response, corals may release tiny symbiotic algae which drains them of color. More importantly, bleaching affects their ability to feed and reproduce.

Severe or prolonged bleaching might kill off corals entirely. Scientists have detected bleached coral in the past two years in oceans around the world. They expect the process to continue thought 2016.

The 2,300-kilometer-long (1,429-mile-long) Great Barrier Reef is the world's largest coral reef system and its largest living structure. It is also among Australia's main tourist attractions, generating around $3.9 billion (3.5 billion euros) annually.

Almost one-half of the coral in the reef's northern third have died in the past three months [in 2016], according to James Cook University professor Terry Hughes. The most affected area is remote and unpolluted, with very little fishing and no coastal development. "That's an absolute catastrophe," Hughes said. "There's nowhere to hide from climate change."

Despite the bad news, scientists claim the problems can be managed with proper funding and political backing. "We are not ready to write the obituary for coral reefs," Professor Hughes said. The scientific community at the conference pledged to work with leaders across the world in order to "curb the continued loss of coral reefs."