Marine heat waves pose a growing threat to human physical and mental health that has been largely overlooked despite mounting evidence of their far-reaching consequences, according to researchers from Adelaide University and the University of Hong Kong. A commentary published in Nature Sustainability outlines how prolonged periods of unusually high ocean temperatures trigger effects that ultimately affect human health, from worsening extreme weather events and reducing seafood supplies to increasing mental health challenges for coastal communities.
The researchers linked the intensification of Hurricane Otis in 2023, which caused an estimated damage bill of more than US$15 billion in Mexico, and Typhoon Doksuri in 2023, which affected more than 2 million people across Asia, to marine heat waves. A toxic algal bloom in South Australia has been similarly linked to human health problems in coastal communities, including respiratory irritation, asthma, and "eco-anxiety," as well as grief, frustration and depression.
Extreme ocean temperatures can contribute to more intense weather systems, increasing risks of injury, death and displacement from storms and flooding, the researchers said. Harmful algal blooms, expected to become more common as marine heat waves intensify, can contaminate seafood and pose serious health risks. Over the longer term, declining fish stocks and reduced seafood production threaten food security for billions of people worldwide, and psychological impacts affect those whose livelihoods and cultural identity are closely connected to the ocean.
The authors called on governments and public health agencies to treat marine heat waves in much the same way they prepare for land-based heat waves. This includes incorporating marine heat wave forecasts into public health planning, considering health impacts in marine and coastal management decisions, and improving collaboration between ocean scientists, health authorities and resource managers. Dr. Laura Falkenberg from Adelaide University's School of Physics, Chemistry and Earth Sciences said that acting proactively would help communities become more resilient as marine heat waves continue to intensify.
