Ningaloo, Australia - A mass bleaching event has been recorded off the Western Australian coast, devastating local ecosystems as a similar event takes a wrecking ball to the iconic Great Barrier Reef.

For the first time in known history, Australia's iconic Great Barrier Reef (GBR) and the Western Australian Ningaloo Reef have been simultaneously hit with heat stress, causing multiple mass bleaching events.

The GBR and Ningaloo reef systems are located on opposite sides of the Australian continent, the former on the east and the latter on the west, making simultaneous bleaching an otherwise unheard-of event.

Coral reef ecosystems are extremely sensitive, and an increase of less than 1 degree Celsius (approximately 1.8 degrees Fahrenheit) can, in a matter of days, result in a mass bleaching event.

Science Infants can remember more than you think, new study reveals

In this case, a mass of warm water has moved and settled over both reefs and stayed there for multiple weeks. For the GBR, it is likely fueled by the gradual end of the La Niña cycle as the Western Pacific heads towards an El Niño warm phase.

"Warm oceans have just cooked the corals this year," ocean scientist Kate Quigley told the AFP. "It wouldn't be amiss to throw in the word 'unprecedented.'"

"It has gone deep, it's not just the top of the reef that is bleaching. Many different species of coral are bleaching."

Derek Manzello, of the US National Oceanic and Atmospheric Administration (NOAA) said that between January 1, 2023, and March 20, 2025, about 83.6% of the world's reefs have been hit by bleaching-level heat stress.

The bleaching of Ningaloo and the GBR are both directly linked to above-average temperatures in our oceans, fueled by man-made climate change and global warming.

It is believed that ongoing bleaching is the worst seen in more than a decade, as the warmer temperatures force coral to expel the algae that give it its color, resulting in its bleached-white appearance.

Environment and Climate Massive earthquake kills over 150 people across Myanmar and Thailand

While not immediately fatal, if this bleaching continues for more than a few days, it becomes likely that the coral will die, devastating local ecosystems and wildlife, including endangered whale sharks.

"What we're seeing is the level of ocean warming is so great, it's overriding the local conditions in some places," Quigley said. "It's just shocking."