Oceans and coastal waters receive a large percentage of our waste and pollutants, including plastic debris, excess nutrients, chemical and radioactive waste from land-based sources, as well as shipping refuse and abandoned fishing gear from sea-based sources. Excess nutrient loads have caused at least 500 dead zones in coastal areas around the world, with impacts on ecosystems such as coral reefs as well as on fishing communities and the productivity of fish stocks.
Marine litter can cause physical harm to marine life through entanglement, ghost fishing, and ingestion; it can also act as a carrier for toxic substances, and transport invasive species across the ocean. Three quarters of marine litter is now composed of plastic, and up to 12.7 million tonnes of plastic waste enter the ocean every year – the approximate equivalent of one garbage truck-full every minute. At this rate, it is estimated that plastic will outweigh fish in the ocean by 2050.