(FILES) This underwater photo taken on June 14, 2024 shows 14-year-old Nannalin "Fleur" Pornprasertsom surveying bleached corals during her coral conservation and citizen science course at Black Turtle Dive around Koh Tao island in the southern Thai province of Surat Thani. The arrival of a potentially powerful El Nino weather system in 2026 could devastate coral reefs around the world already weakened by back-to-back rounds of bleaching, scientists warn. (Photo by Lillian SUWANRUMPHA / AFP via Getty Images) / To go with AFP story oceans-environment-climate-El Nino, FOCUS by Sara HUSSEIN