Global assessment warns 96% of shallow-water reef systems face collapse

A global assessment released Thursday classifies 96% of shallow-water coral reef systems as critically endangered and warns they could disappear by 2075, according to The Korea Times. Warming seas and marine heat waves are the primary threats.

Reefs sustain a quarter of marine species while supporting fisheries and tourism and buffering coasts against storms and erosion. Their collapse would mean losing not just living coral but the habitat that supports diverse marine life.

The International Union for Conservation of Nature announced its first global assessment of coral reef ecosystems on the sidelines of a U.N. biodiversity conference in Albania, The Korea Times reported. It examined 127 tropical and subtropical ecoregions encompassing 72,726 square miles of reefs.

Systems placed in the critically endangered category include the Great Barrier Reef, the Coral Triangle, the Mesoamerican Barrier Reef System and reefs in the Red Sea. Ecosystem collapse occurs when hard corals give way to algae, rubble and sponges, leaving the habitat unable to sustain its previous range of marine life.

Climate change is the most consistent driver of reef decline worldwide, according to the assessment described by The Korea Times. Pollution, overfishing and coastal development also weaken reef survival. A survey cited in the report found that harmful bleaching had affected 84% of ocean reefs a year earlier.

A separate IUCN study published in Nature a week earlier found that nearly 44% of reef-building coral species faced an elevated risk of extinction because of climate change. That finding concerns individual species, while the new assessment examines the risk of entire reef ecosystems collapsing.

IUCN Director General Grethel Aguilar called for emissions cuts, stronger reef protection and restoration and sustained investment in coastal ecosystems and the communities that rely on them, according to The Korea Times. Experts also advocated reducing pollution and overfishing.

Recovery remains possible in some areas, assessment scientific lead Mishal Gudka said, according to The Korea Times. Andrew Baker, director of the Coral Reef Futures Lab at the University of Miami, said emerging technology and new restoration methods could help reefs endure while broader environmental changes take place.