Global warming has led to severe coral bleaching along the coast of Western Australia (WA), an event that scientists are calling the worst on record. This ecological disaster follows a long and intense marine heatwave that affected the area from last August to May of this year. The extended period of high-water temperatures caused significant thermal stress on the coral. This stress leads to a process called bleaching, where the coral expels the symbiotic algae that give them their vibrant colors and provide sustenance. This process often precedes coral death. Climate change has now impacted areas that were previously considered resilient.
The damage is extensive, covering about 1,500 kilometers (932 miles) of coastline, and assessments are expected to take several months. This regional crisis reflects a larger, two-year global coral bleaching event caused by rising ocean temperatures around the world. Typically, eight weeks of sustained heat stress can kill coral. Preliminary estimates from Australia’s marine science agency suggest that many of WA’s reefs faced between 15 and 30 weeks of dangerous conditions.
Dr. James Gilmour, a researcher from the Australian Institute of Marine Science (AIMS), pointed out the unusual nature of this event. He mentioned that the duration and intensity of the heat stress, along with its broad reach across different regions, are phenomena not seen before on most Western Australian reefs. A recent report by AIMS researchers confirmed that the 2024-25 season recorded the worst coral bleaching for WA’s reefs, affecting both the northwestern and central regions.
Dr. Gilmour expressed particular worry for areas that had historically shown resilience due to infrequent or nonexistent bleaching events. He highlighted the Rowley Shoals, North Kimberley, and Ningaloo as examples of these previously strong ecosystems that have now suffered serious damage. He regretted that climate change has finally affected these crucial reefs. It is important to note that Ningaloo Reef is a World Heritage site, similar to the Great Barrier Reef on Australia’s east coast, which has also experienced significant coral bleaching in recent years.
Recently, a separate report revealed a major decline in coral on the Great Barrier Reef, the largest coral system in the world, stretching over 2,300 kilometers (1,429 miles). This decline is the most significant recorded in nearly four decades. Federal Environment Minister Murray Watt, speaking to the Australian Broadcasting Corporation, stressed the urgent need for both Australia and the global community to take action, including achieving net-zero emissions, due to the coral damage at Ningaloo.
Dr. Gilmour further explained the increasing frequency, intensity, and wide reach of bleaching events linked to climate change. He highlighted that coral reefs usually need a recovery time of 10 to 15 years, but now they do not have enough time to heal between these increasingly destructive events. He firmly stated that climate change, driven by carbon emissions, remains the biggest threat to coral reefs, both regionally and globally. The United Nations has previously warned that even if global temperature rises are limited to 1.5 degrees Celsius above pre-industrial levels, an alarming 70 to 90 percent of the world’s tropical coral reefs are still expected to disappear.
