Oceans & pollution
Marine Debris (Marine Plastic Pollution)
Definition
Marine debris (marine litter) is any persistent, manufactured or processed solid material discarded, disposed of or abandoned in the marine and coastal environment (UNEP, 2009). Plastics dominate by volume; impacts include entanglement and ingestion by hundreds of species, habitat damage, transport of invasive species, and breakdown into microplastics.
References
UNEP 2009 definition, entanglement and ingestion impacts
Overview
What it means
Sources are both land-based (mismanaged waste, rivers, stormwater) and sea-based (fishing gear, shipping). Once at sea, plastics fragment but do not biodegrade on human timescales, accumulating in gyres, sediments and food webs.
How it is used
The term frames national action plans, fishing-for-litter schemes, single-use plastics bans and negotiations toward a global plastics treaty; monitoring uses beach surveys and trawl counts.
Why it matters
Marine debris is one of the most visible and politically tractable pollution crises, linking waste management, product design and ocean health — and driving global regulation of plastics.