Marine litter has become one of the most pressing environmental and maritime governance challenges worldwide. Across the Atlantic Ocean, the Mediterranean Sea, the Pacific Ocean and the Indian Ocean, plastic waste continues to accumulate at alarming levels. Current estimates indicate that between 75 and 199 million tons of plastic are already present in the world’s oceans, representing around 85% of all marine litter. Scientists warn that by 2050, plastic volumes could exceed fish stocks if no decisive action is taken. Around 80% of marine litter originates from land-based activities, travelling through rivers, wastewater systems and coastal runoff before reaching major maritime routes and coastal waters. Once in the marine environment, plastics persist for decades or even centuries, fragmenting into microplastics. An estimated 24 trillion microplastic particles now float at the ocean surface, creating long-term ecological and operational risks.
Environmental, operational and economic consequences
The consequences of marine litter extend far beyond visible pollution. In European waters, more than 70% of marine species are affected by plastic debris. In some Mediterranean coastal areas, this figure approaches 100%. A study conducted between 2014 and 2018 in the North-East Atlantic revealed that 92% of 393 northern fulmars examined had ingested plastic, with an average of 21 particles per bird. These findings confirm that marine litter is now embedded in marine food chains.
Fishing activities are directly impacted. Each year, approximately 640,000 tons of fishing gear are lost or abandoned at sea. This leads to “ghost fishing”, where discarded nets continue trapping fish, turtles, seabirds and marine mammals for years. Lost fishing gear also damages seabed habitats and weakens fisheries sustainability, particularly in the Mediterranean Sea and the North Sea.
Marine litter also raises maritime safety concerns. Floating debris can damage propellers and rudders, interfere with navigation and increase operational risks for commercial vessels. For ports and coastal states, insufficient port reception facilities and weak waste management systems remain structural vulnerabilities. According to the United Nations, the global economic cost of marine plastic pollution is estimated between 6 and 19 billion USD annually, affecting fisheries, tourism and coastal economies.
As we previously reported in our analysis of port waste management challenges in the Mediterranean Sea, inadequate infrastructure and inconsistent enforcement continue to undermine progress.
International governance and France’s regulatory response
At the international level, the International Maritime Organization (IMO) regulates ship-generated waste under Annex V of the MARPOL Convention, which prohibits the discharge of plastics at sea. Over 150 states are parties to this framework. The IMO’s updated 2025 Action Plan aims to:
- Reduce plastic waste from vessels
- Strengthen port reception facilities
- Improve reporting of lost fishing gear
- Introduce mandatory reporting of lost containers (effective January 2026)
- Address the environmental risks of plastic pellet transport
The IMO also implements technical cooperation programmes, including support for developing coastal states to improve waste management capacity and maritime compliance.
Within Europe, the Marine Strategy Framework Directive sets the objective of achieving “Good Environmental Status” in EU marine waters. France has transposed this directive into national law and implemented the “Zero plastic entering the ocean” Action Plan (2020–2025). National measures include:
- Reduction of single-use plastics under the AGEC law
- Strengthened extended producer responsibility schemes
- Prevention of industrial plastic pellet leaks
- Improved waste management in ports
- Monitoring of coastal macro-debris
French coastal monitoring data shows that 87% of litter found on metropolitan shorelines is plastic, with 15% consisting of single-use items. These figures underline the structural link between land-based consumption patterns and marine litter.
For a broader international perspective on marine litter trends and governance, readers may consult the latest United Nations global assessment on plastic pollution.
Marine litter remains a cross-border challenge affecting the Atlantic Ocean, Mediterranean Sea, Baltic Sea, North Sea, Red Sea, Caribbean Sea, Gulf of Mexico and Antarctic waters. While international maritime regulation under MARPOL is strengthening, long-term success depends on prevention at source, effective port infrastructure and coordinated enforcement across coastal states.
