Human actions are causing widespread damage to ocean ecosystems and threatening human health, a new report suggests.

Share on Pinterest
Aryfahmed/Getty Images

An international team of researchers has highlighted the widespread damage human actions have caused to the world’s oceans, and in turn, to human health.

The research, which appears in the Annals of Global Health, lays out a series of recommendations for alleviating these damaging effects.

The Earth’s oceans are crucial to sustaining life on the planet. They play a central role in adding oxygen into the atmosphere and absorbing carbon dioxide, helping to stabilize the effects of global heating.

They provide food to billions of people, are central to the livelihoods of millions who live or work on or near them, and have an important role in providing several essential medicines.

For people who live close to oceans — such as coastal communities, small-island communities, populations in the high Arctic, and peoples in parts of the global south — they are central to societal and cultural practices, traditions, and ways of life.

However, the world’s oceans are under threat, primarily from the actions of humans. And as the health of oceans deteriorates, so too does humans’ health, particularly those people who live close to them.

The researchers behind the present study looked in detail at current scientific evidence demonstrating the crucial role the world’s oceans play in planetary health. They also looked at the key factors that are damaging the health of the oceans.

They found that human actions are central to this damage in a complex manner, whereby specific destructive actions exist in a relationship with other damaging actions.

A key example of this is human-influenced climate change, as the Intergovernmental Panel on Climate Change has made clear.

As global temperatures increase, the rate of sea-ice melting increases. This releases forms of harmful algae and bacteria into previously uncontaminated waters.

Sea level rises and increasingly violent coastal storms threaten the well-being of coastal populations. Increasing levels of atmospheric carbon dioxide make the oceans acidic, which destroys the crucial foundations of ocean food chains.

In addition, the effects of climate change exacerbate another significant cause of damage to the oceans’ health: pollution.

For Prof. Philip Landrigan, the corresponding author of the study and the Director of the Global Pollution Observatory at Boston College, Massachusetts:

“Simply put: ocean pollution is a major global problem, it is growing, and it directly affects human health. People have heard about plastic pollution in the oceans, but that is only part of it. Research shows the oceans are being fouled by a complex stew of toxins including mercury, pesticides, industrial chemicals, petroleum wastes, agricultural runoff, and manufactured chemicals embedded in plastic.”

“These toxic materials in the ocean get into people, mainly by eating contaminated seafood,” he adds.

According to the researcher: “We are all at risk, but the people most seriously affected are people in coastal fishing communities, people on small island nations, indigenous populations, and people in the high Arctic. The very survival of these vulnerable populations depends on the health of the seas.”

The study highlights that global heating and the associated increase in sea-surface temperatures combine with the polluted oceans, increasing the spread of bacteria that cause cholera and increasing the prevalence and intensity of harmful algal blooms.

However, despite their worrying report, the study authors suggest that the situation is changeable.

For Prof. Landrigan, “[t]he key thing to realize about ocean pollution is that, like all forms of pollution, it can be prevented using laws, policies, technology, and enforcement actions that target the most important pollution sources.”

“Many countries have used these tools and have successfully cleaned fouled harbors, rejuvenated estuaries, and restored coral reefs. The results have been increased tourism, restored fisheries, improved human health, and economic growth. These benefits will last for centuries,” he notes.

The authors of the study make a series of recommendations to help reverse the current harm the oceans are undergoing. These are:

  • preventing mercury pollution by stopping the combustion of coal and controlling the use of mercury in gold mining
  • considering a global ban on single-use plastics
  • improving waste management to enable more recycling of plastics
  • reducing the release of pollutants into coastal waters and rivers from intensive agriculture and sewerage facilities
  • creating Marine Protected Areas to reduce the trawling of fragile fish stocks and the knock-on damage to marine ecosystems
  • improving the monitoring of ocean pollution
  • ensuring all countries have marine pollution control programs

The authors also recommend transitioning to a circular economic model, moving away from a model based on continuous growth and the consequent exhaustion of the planet’s resources.