Plastic pollution has become one of the most pervasive environmental problems of the modern era. Global plastic production reached approximately 460 million tonnes in 2019, and less than 10 percent of all plastic ever produced has been recycled. The remainder has been incinerated, buried in landfills, or — in the case of an estimated 8 million tonnes per year — entered the ocean. Once in the ocean, plastic does not biodegrade; it photodegrades — breaking into progressively smaller particles called microplastics. These microplastics have been found in the deepest ocean trenches, in Arctic sea ice, in marine wildlife, and in the bodies of humans.
The ecological consequences of marine plastic are significant but incompletely understood. Large plastic items cause direct harm: entanglement and ingestion kill hundreds of thousands of seabirds and marine mammals annually. Microplastics are absorbed into the food web at the base: phytoplankton and zooplankton ingest microplastic particles, and the contamination moves up the food chain. The long-term health consequences of microplastic ingestion for humans remain a subject of active research.
Proposed solutions range from the individual (consumer behaviour change, single-use plastic reduction) to the systemic (extended producer responsibility, binding international treaties). A UN treaty on plastic pollution was under negotiation as of 2024. The most effective interventions are those that reduce plastic production at source rather than managing plastic waste after it has been produced.
