The Great Barrier Reef, located off the coast of northeastern Australia, stands as the world’s largest coral system. Over a span of 36 years, scientists have recorded a remarkable amount of coral growth, yet the reef remains threatened by climate-driven risks that continue to affect its health, according to the latest annual state of the reef assessment released this week.
Australia’s yearly assessment of the Great Barrier Reef notes that by 2022 the reef showed a notable rebound, reaching the highest levels of coral cover observed by the Long-Term Monitoring Programme in the northern and central zones, based on findings from the Marine Sciences Institute.
The Long-Term Monitoring Programme report, begun 36 years ago, shows that 38 of 87 reefs surveyed between August 2021 and May 2022 had coral cover ranging from 10 to 30 percent. Another 28 reefs exhibited 30 to 50 percent coverage, marking a meaningful rise from the figures recorded in the preceding year’s survey of the reef system.
Acropora Corals Elkhorns
Much of the recent gains are tied to the expansion of Acropora, commonly called elkhorn corals, which form a dominant portion of the reef’s hard coral cover. The Australian Institute of Marine Sciences explained that this group is highly prolific and contributes heavily to the recent uptick in hard coral abundance.
The Australian Institute of Marine Sciences also warned that Acropora species are particularly vulnerable to wave damage from strong winds and tropical cyclones. They may bleach when surface waters warm and are susceptible to predation by crown-of-thorns starfish. An AIMS expert noted that large increases in hard coral cover can be quickly offset by disturbances affecting reefs dominated by Acropora corals.
Pests and Whitewash
Across the southern portion of the Great Barrier Reef, coral growth declined from 38 percent in 2021 to 34 percent in the current year. The presence of crown-of-thorns starfish highlighted how fragile this ecosystem can be. The executive leadership at AIMS stressed that the reef remains exposed to more frequent and longer-lasting acute disturbances. As a World Heritage Site, the reef has endured several bleaching events in years such as 1998, 2002, 2016, 2017, and 2020, with La Niña conditions contributing to cooler surface temperatures in parts of Australia at certain times.
Across the entire reef system, biodiversity is vast, encompassing about 400 coral species, roughly 1,500 fish species, and around 4,000 mollusk species. The reef began showing stress in the 1990s as warming oceans and rising acidity from higher atmospheric CO2 contributed to a gradual decline in resilience and health.
Experts emphasize that ongoing monitoring, protective management actions, and targeted conservation efforts are essential to maintaining the gains in coral cover while reducing vulnerability to climate-related events. The reef’s status remains a testament to both its ecological complexity and the need for continued stewardship that supports resilient coral communities for future generations.