An international group of scientific experts co-directed by CNRS oceanographer Jean-Pierre Gattuso has stated the requirements for coral reef survival in an article published in Biological Conservation. Over 500 million people rely on coral reefs for the protection they confer against submersion, the fishing resources they offer, and the tourism they help attract. Yet these ecosystems are among the most threatened by global warming: since the 1980s, there has been a rise in the number of bleaching episodes, during which corals expel the microscopic algae that keep them alive. While these events are reversible if the temperature change is only brief, prolonged bleaching can kill corals and the ecosystems associated with them.