The Great Barrier Reef, a global icon of marine biodiversity, has suffered unprecedented coral loss, with Australian researchers reporting the highest mortality on record. Surveys conducted by the Australian Institute of Marine Science revealed up to 72% coral mortality across 12 reefs, driven by a summer of extreme weather, including mass bleaching, two cyclones, and flooding.
Severe Decline in Northern Reefs
In the reef’s northern section, a third of hard coral perished the largest annual decline in 39 years of monitoring. Scientists fear similar devastation may have occurred in other parts of the 2,300-kilometer-long reef, known as the world’s largest living structure.
Mass bleaching occurs when rising sea temperatures force corals to expel the microscopic algae (zooxanthellae) that give them color and nutrients. Prolonged heat stress leaves corals white and lifeless. This year marked the fifth mass bleaching event in just eight years, with rapidly growing acropora coral suffering the most severe losses.
Lead researcher Mike Emslie described the recent summer as “one of the most severe events” for the reef, with heat stress surpassing previous records. WWF-Australia’s head of oceans, Richard Leck, expressed grave concern, calling the findings “our worst fears.”
“The reef can’t withstand repeated blows like this,” Leck warned. “We are nearing a tipping point.”
Call for Urgent Climate Action
The devastation highlights the urgent need for stronger climate policies. Leck emphasized that Australia, as a major coal and gas exporter, must drastically reduce emissions at least 90% below 2005 levels by 2035 and transition away from fossil fuels to protect the reef’s future.
The Great Barrier Reef’s fate is inextricably linked to global efforts to combat climate change. Scientists stress that immediate action is critical to preventing further loss of this natural wonder, which supports a vast array of marine life and generates significant revenue through tourism.
The full impact of this year’s bleaching will become clearer when more extensive survey data is released next year. Until then, the world watches, hoping for a shift in policies to safeguard this fragile ecosystem.
Reference: https://www.sciencealert.com/record-breaking-coral-death-in-the-great-barrier-reef-alarms-scientists