World-famous coral reefs along the coast of Western Australia (WA) are facing a catastrophic bleaching event, the worst on record, as a result of the state experiencing its "longest, largest, and most intense" marine heatwave. Following a period of elevated sea temperatures from last August to May, the coral reefs have undergone severe heat stress, leading to the expulsion of the crucial algae that provide coral with both life and color. This phenomenon, known as bleaching, frequently results in coral death.
The extent of the damage, which stretches over 1,500 kilometers (932 miles), includes regions that had previously been untouched by the harsh impacts of climate change. Globally, coral reefs have entered a two-year-long period of mass bleaching due to escalating ocean temperatures. Affected coral typically succumbs to damage after just eight weeks of heat stress, and estimates indicate that many of WA’s reefs have suffered serious degradation—with losses between 15% and 30%.
James Gilmour from the Australian Institute of Marine Science (AIMS) noted that the duration and severity of heat stress, coupled with its widespread impact, is unprecedented across WA’s reefs. A new report confirms that the upcoming 2024-25 season marks the most significant coral bleaching event recorded for both northwestern and central coral reefs in the region.
Once resilient areas, such as Rowley Shoals, the north Kimberley, and Ningaloo Reef, are now facing alarming coral losses. The Ningaloo Reef, a World Heritage site, now mirrors the troubling health of the Great Barrier Reef on Australia’s east coast, which recently recorded its steepest decline in coral over the last four decades.
In response, Federal Environment Minister Murray Watt emphasized the coral damage at Ningaloo as a critical reminder of the necessity for immediate action to combat climate change and achieve net-zero emissions globally. The increasing frequency, intensity, and reach of coral bleaching events, driven by climate change, leave little recovery time for affected reefs. Dr. Gilmour stresses that carbon emissions remain the greatest threat to coral reefs, not just in Australia but globally. The UN has previously indicated that limiting global temperature rises to just 1.5 degrees Celsius could still result in the loss of 70 to 90% of the world’s tropical coral reefs.
