Researchers from Adelaide University and the University of Hong Kong say marine heatwaves should be given the same urgency as heatwaves on land. A new paper published in Nature Sustainability argues that these extreme ocean warming events pose a rising threat to human physical and mental health that has largely been overlooked.
The study outlines how prolonged periods of unusually high ocean temperatures trigger a cascade of effects that reach far beyond coral reefs and fisheries. Impacts range from intensifying extreme weather and reducing seafood supplies to increasing mental health challenges in coastal communities.
Lead author Dr Laura Falkenberg, from Adelaide University’s School of Physics, Chemistry and Earth Sciences, said the environmental damage from marine heatwaves has long been recognized, yet their effects on people have received far less attention.
“Marine heatwaves are no longer just recognized as an environmental issue; they are increasingly also perceived as a human health issue,” Dr Falkenberg said.
“Our paper highlights that these events can influence people’s health in many different ways, both directly and indirectly. They can intensify storms and atmospheric heatwaves, affect the availability and safety of seafood, disrupt livelihoods and contribute to anxiety, grief and other mental health impacts in communities that depend on healthy oceans.”
Marine heatwaves have become more frequent, longer lasting and more intense as the climate warms. They have already been linked to mass mortality events among marine life, widespread coral bleaching, harmful algal blooms and major disruptions to fisheries and aquaculture.
These environmental shifts carry direct consequences for people. Very warm oceans can fuel more powerful weather patterns, increasing the likelihood of injury, death and displacement from storms and flooding. Harmful algal blooms, which are projected to increase along with marine heat waves, can contaminate seafood and present serious health threats. Over the longer term, declining fish stocks and reduced seafood production threaten food security for billions of people.
The paper also points to psychological effects. Damage to marine environments and pressure on people whose lives and cultural identities depend upon the ocean can give rise to eco-anxiety, grief and other mental health problems.
In South Australia, a toxic algal bloom in 2025 produced high levels of eco-anxiety, along with grief, frustration, depression, respiratory irritation and asthma.
“Many people rely on healthy oceans not only for food and income, but also for recreation, cultural identity and their overall sense of wellbeing,” Dr Falkenberg said.
“When marine ecosystems suffer, the impacts ripple through communities. We are seeing increasing evidence that these changes can contribute to eco-anxiety, grief and other mental health challenges, particularly for people who feel deeply connected to the marine environment.”
The intensification of Hurricane Otis in 2023, which caused more than US$15 billion in damage in Mexico, and Typhoon Doksuri the same year, which affected more than two million people across Asia, have both been linked to marine heatwaves.
The authors urge governments and public health agencies to incorporate marine heatwave forecasts into public health planning, weigh health impacts in marine and coastal management decisions, and strengthen collaboration between ocean scientists, health authorities and resource managers.
“Recognizing these health impacts is the first step towards better protecting communities,” Dr Falkenberg said.
“If we only respond after disasters occur, we will continue to experience greater impacts than if we had acted proactively. By understanding the links between ocean health and human health, we can develop better policies that protect both people and the marine ecosystems they depend on.”
The paper, titled “Recognizing the human health impacts of marine heatwaves,” appears in Nature Sustainability.
