An increase in marine heatwaves over the past two years caused billions of dollars of damage around the world and despite warnings interventions were limited, according to an international team of researchers.
Dr Karen Filbee-Dexter and ARC Laureate Fellow Professor Thomas Wernberg, from The University of Western Australia's Oceans Institute, were co-authors of the study published in Nature Climate Change.
"Intensifying marine heatwaves are driving ocean temperatures to record-breaking levels, surpassing anything observed in modern history," Dr Filbee-Dexter said.
"The extreme warming events are fuelled by climate change, and are disrupting marine ecosystems, threatening fisheries and intensifying severe weather patterns.
"We need urgent action to reduce global emissions and prevent further extreme temperatures in our oceans."
The study found that in 2023 and 2024 there were nearly three-and-a-half times the number of marine heatwave days and almost 10 per cent of the ocean hit record-high temperatures.
The record high temperatures impacted ocean processes, marine species, ecosystems and coastal communities, and drove extreme weather and flooding on land, with economic consequences.
In Australasia, prolonged marine heatwaves led to severe coral bleaching across Australia and the Pacific Islands, severe flooding and landslides in Australia, and stronger tropical cyclones.
Marine heatwaves also forced the temporary closure of oyster farms in Australia and led to increased whale and dolphin strandings in New Zealand.
"The heat we are adding to the ocean today will be felt for decades," Professor Wernberg said.
"Without urgent climate action, we are on track to lose significant coastal ecosystems including kelp forests and coral reefs within our lifetimes.
"We cannot rely on restoring nature after we break it, we must phase out fossil fuels before it's too late."
Researchers warn that as long as the rate of human-induced climate change keeps rising, marine heatwaves will continue to worsen, and more proactive action is needed to avert the damage.
