A Growing Threat to Human Health

Marine heatwaves are no longer just an ocean crisis—they’re becoming a growing threat to human health.

Marine heatwaves are emerging as a global threat to human health, food security and coastal communities as oceans continue to heat up.

Marine Heatwaves and Human Health: A Growing Global Threat

Marine heatwaves are affecting more than coral reefs and fisheries. New research shows that these extreme ocean warming events could also increasingly threaten people’s physical and mental health.

Marine Heatwaves are More Than an Ocean Problem

Researchers from Adelaide University and the University of Hong Kong are calling for marine heatwaves to be recognized as a major public health issue, arguing their impacts on people have been largely overlooked despite increasing evidence of their far-reaching consequences.

The intensification of Hurricane Otis in 2023 and its effects on Mexico (an estimated damage bill of more than US$15 billion), as well as the impacts of Typhoon Doksuri in 2023 (which affected more than two million people across Asia), have both been linked to marine heatwaves.

In South Australia, the devastating algal bloom has also been linked to a myriad of human health problems in coastal communities.

Extreme Ocean Warming: The Health Risks We Can’t Ignore

A new paper published in Nature Sustainability outlines how prolonged periods of unusually high ocean temperatures can trigger a cascade of effects that ultimately affect human health, from worsening extreme weather events and reducing seafood supplies to increasing mental health challenges for coastal communities (1^✔ ✔Trusted Source
Recognizing the human health impacts of marine heatwaves

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Lead author Dr. Laura Falkenberg, from Adelaide University’s School of Physics, Chemistry and Earth Sciences, said while scientists had long understood the environmental damage caused by marine heatwaves, their effects on people had received far less attention.

Marine Heatwaves: No Longer Just an Environmental Problem

“Marine heatwaves are no longer just recognized as an environmental issue; they are increasingly also perceived as a human health issue,” Dr. Falkenberg said.

How Marine Heatwaves are Hitting Human Health From All Sides

“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.”

From Coral Bleaching to Fishery Disruption: The Cost of Hotter Seas

Marine heatwaves have become more frequent, longer lasting and more intense as the climate warms. They have already been linked to mass mortality events affecting marine life, widespread coral bleaching, harmful algal blooms and major disruptions to fisheries and aquaculture.

The researchers say these environmental changes can have profound consequences for people.

Marine Heatwaves: How Hotter Oceans Threaten Human Health

Extreme ocean temperatures can contribute to more intense weather systems, increasing the risks of injury, death and displacement from storms and flooding. Harmful algal blooms, which are expected to become more common due to marine heatwaves, can contaminate seafood and pose serious health risks. Longer term, declining fish stocks and reduced seafood production threaten food security for billions of people worldwide.

The paper also highlights the psychological impacts of witnessing the loss of marine ecosystems and the stress experienced by people whose livelihoods and cultural identity are closely connected to the ocean.

In 2025, the toxic algal bloom caused high levels of ‘eco-anxiety’ in South Australia, causing grief, frustration and depression, as well as 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 authors argue that governments and public health agencies should begin treating marine heatwaves in much the same way they prepare for land-based heatwaves.

This includes incorporating marine heatwave 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. Falkenberg said taking action before crises occur would help communities become more resilient as marine heatwaves continue to intensify.

“Recognizing these health impacts is the first step towards better protecting communities,” she said.

Don’t Wait for Disaster: Protect the Ocean, Protect Our Health

“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.”

Reference:

1. Recognizing the human health impacts of marine heatwaves – (https://www.nature.com/articles/s41893-026-01892-x)

Source-Eurekalert