Microplastics Pose Growing Threat to Marine Environments as Global Plastics Treaty Nears Completion  

Hauwa Ali

 

As world leaders gather in Busan, South Korea, to finalise the Global Plastics Treaty, marine scientists warn that the agreement may fail to address a critical threat to the world’s oceans: the unchecked accumulation of microplastics. These tiny particles, formed by the breakdown of larger plastic debris, have infiltrated marine ecosystems unprecedentedly, with devastating consequences for ocean health.  

 

While the treaty aims to eliminate plastic pollution by 2040, researchers argue that its focus on reducing future pollution overlooks the urgent need to mitigate the impact of the billions of tons of plastic already polluting marine environments.

 

Microplastics, often less than 5 millimetres in size, originate from the slow degradation of more considerable plastic waste discarded into the environment. Once in the ocean, these particles persist for centuries, contaminating water columns, seabeds, and coastlines. Marine species ranging from plankton to whales unknowingly ingest microplastics, which can disrupt their feeding and reproductive systems.  

 

“Even if we drastically reduce plastic entering the ocean, the debris already there will fragment into microplastics for decades,” said Zhenna Azimrayat-Andrews, a marine scientist and co-author of a study published in Nature Communications. “This ongoing breakdown means marine environments will remain at risk for generations.”  

 

Research shows that microplastics have already infiltrated the food chain, affecting commercially important seafood species like shellfish and fish. This threatens marine biodiversity and compromises food security for millions of people who rely on oceans as their primary source of protein.

 

The impact of microplastics extends beyond individual species. Scientists warn that these particles disrupt critical ocean processes that regulate global climate systems. For example, plankton, which form the foundation of the marine food web, play a key role in carbon sequestration by absorbing carbon dioxide. Microplastics interfere with plankton feeding and growth, potentially reducing the ocean’s ability to act as a carbon sink.  

 

Additionally, studies suggest that microplastics alter the physical and chemical properties of ocean water. These changes can weaken ecosystems such as coral reefs, which are already under threat from climate change and overfishing.  

 

While much of the treaty’s focus has been on preventing new plastic pollution, scientists emphasize that addressing **legacy plastics**—the trillions of pieces of plastic waste already present in the environment—is equally crucial. These plastics, which have accumulated over decades, are the primary source of microplastics.  

 

According to researchers from the University of Cambridge, GNS Science in New Zealand, and The Ocean Cleanup in the Netherlands, legacy plastics represent a long-term threat that cannot be mitigated simply by cutting current pollution rates.  

 

“Microplastics don’t just vanish,” said Azimrayat-Andrews. “Without targeted efforts to clean up existing waste, they will continue accumulating and harming marine environments, even if we achieve significant reductions in plastic production.”  

 

Scientists are urging negotiators at the Busan summit to include marine clean-up strategies as a core pillar of the treaty. Efforts like intercepting plastic waste in rivers before it reaches the ocean and removing debris from coastlines and beaches could prevent further microplastic fragmentation.  

 

Their research suggests that removing as little as 3% of legacy plastic waste annually, combined with aggressive prevention measures, could significantly slow the accumulation of microplastics in marine ecosystems. However, scaling up clean-up technologies will require substantial funding and international cooperation.  

 

Organisations like The Ocean Cleanup have already demonstrated the feasibility of removing plastic waste from significant river systems. Expanding such initiatives globally could help bridge the gap between prevention and restoration.

 

The infiltration of microplastics into marine environments is causing cascading effects throughout ocean ecosystems. Marine animals often mistake plastic particles for food, leading to physical blockages in their digestive systems and exposure to toxic chemicals.  

 

Ingesting plastic can be fatal for species like seabirds and sea turtles. Studies estimate that more than 700 marine species are affected by plastic pollution, with many at risk of population decline due to habitat degradation and food scarcity.  

 

Additionally, the toxic chemicals absorbed by microplastics can accumulate in predator species, including those consumed by humans, creating a public health concern that further underscores the urgency of addressing the issue.  

 

The Global Plastics Treaty, the first legally binding international agreement to tackle plastic pollution, has been hailed as a landmark opportunity to protect marine environments. However, the current draft focuses heavily on prevention and recycling, with limited provisions for addressing the waste already polluting the oceans.  

 

Marine scientists argue that a treaty that fails to include robust clean-up efforts risks leaving future generations with oceans choked by microplastics.  

 

“Prevention alone isn’t enough,” said the researchers in their commentary. “We need a comprehensive plan that removes existing plastics from marine environments while ensuring no new plastic waste enters the ocean.”  

 

As the Busan negotiations conclude, the question remains: will world leaders rise to the challenge of crafting a treaty that addresses the full scope of the plastic pollution crisis?  

 

For now, the fate of marine ecosystems—and the communities that depend on them—hangs in the balance. Without immediate action to tackle the dual threats of new pollution and legacy plastics, microplastics will continue to erode the health of the oceans, undermining their role as a vital resource for life on Earth.