The impacts of marine heatwaves are extending beyond environmental damage, with researchers warning on Aug. 10 that these extreme ocean warming events increasingly threaten human physical and mental health.
A team from Adelaide University and the University of Hong Kong said marine heatwaves should be recognized as a major public health issue. They argue that the effects on people have been largely overlooked despite evidence showing far-reaching consequences. The intensification of Hurricane Otis in 2023, which caused more than US$15 billion in damages to Mexico, and Typhoon Doksuri in 2023, affecting over two million people across Asia, have both been linked to marine heatwaves. In South Australia, algal blooms associated with these events have led to various health problems in coastal communities.
A new paper published in Nature Sustainability outlines how prolonged periods of unusually high ocean temperatures can trigger a cascade of effects impacting human health. These include worsening extreme weather events, reducing seafood supplies, and increasing mental health challenges for coastal populations.
Lead author Dr. Laura Falkenberg from Adelaide University's School of Physics, Chemistry and Earth Sciences said scientists have long understood the environmental damage caused by marine heatwaves, but their effects on people have received less attention. "Marine heatwaves are no longer just recognized as an environmental issue; they are increasingly also perceived as a human health issue," Falkenberg said.
The paper highlights that harmful algal blooms may become more common due to marine heatwaves, contaminating seafood and posing serious risks. Declining fish stocks threaten food security for billions worldwide. Witnessing loss of marine ecosystems can cause psychological distress such as eco-anxiety or grief—impacts seen during the toxic algal bloom in South Australia in 2025, which resulted in increased respiratory irritation and asthma alongside mental distress.
The authors urge governments and public health agencies to treat marine heatwaves similarly to land-based ones by incorporating forecasts into planning processes and improving collaboration between ocean scientists and resource managers. "Recognising these health impacts is the first step towards better protecting communities," Falkenberg said.
