The Great Barrier Reef Has Lost Half Its Coral Since the 1990s

One of the world’s greatest natural wonders is also one of the most endangered. The Great Barrier Reef, off the northeast coast of Australia, has lost half of its coral since the 1990s — and the cause is climate change, researchers from the ARC Centre of Excellence for Coral Reef Studies at Queensland’s James Cook University found in a study released today.

The number of all coral sizes on the planet’s largest reef has declined by more than 50% since the 1990s, one of the report’s co-authors Terry Hughes told CNN in a statement.

While coral growth has suffered all around the world, the impact on the Great Barrier Reef is remarkably pronounced, especially when compared to the baselines set in 1995 and 1996. “We used to think the Great Barrier Reef is protected by its sheer size — but our results show that even the world's largest and relatively well-protected reef system is increasingly compromised and in decline,” said Hughes.

In the study’s summary, it noted damage in particular areas, attributed to the climate crisis: “Declines were particularly pronounced in the northern and central regions of the Great Barrier Reef, following mass coral bleaching in 2016 and 2017.”

The main trigger of the decline is rising ocean temperatures, which causes the coral bleaching — a phenomenon when coral expels the algae in their tissues and turns white since the water is too warm, the National Ocean Service describes. While the change doesn’t kill the coral, it causes it to survive under extreme stress, putting it at greater potential for death.

Record-breaking temperatures in the early part of this year, as well as other mass bleaching events in recent years, have contributed to the detrimental effects, CNN reports.

The reason the disappearing coral is so alarming: Without reefs, there wouldn’t be oceans, which cover 70% of Earth’s surface. “Somewhere between a quarter and a third of all marine species everywhere has some part of their life cycle in coral reefs,” reef expert John “Charlie” Veron, nicknamed “The Godfather of Coral,” told CNN in 2018. “So, you take out coral reefs and a third to a quarter of all marine species gets wiped out. Now that is ecological chaos, it is ecological collapse.”

Closer to home, half of the coral reefs in the U.S. were lost in a single year during a mass bleaching event in 2005 when the warm Caribbean waters surrounding the U.S. Virgin Islands and Puerto Rico spread south.