More than 70% of our planet’s surface is covered by oceans, which support a wide range of habitats and incredible biodiversity. Unfortunately, the marine environment is heavily used as a dumping ground for household and industrial waste — either directly or via rivers — leading to potentially severe impacts on ecosystems and the economy.
Marine litter refers to any persistent, manufactured, or processed material that is discarded, disposed of, or abandoned along coastlines or at sea. It is a growing global problem and a direct threat to the marine environment, which gained widespread attention after the discovery of the massive “garbage patch” in the North Pacific Gyre.
What we see washed up on beaches represents only a small fraction of the total marine litter (15%). According to the United Nations Environment Programme (UNEP), another 15% floats on the surface or is suspended in the water column (deeper than 40 cm). The remaining 70% lies on the seafloor, out of sight.
Marine litter is made up of a wide variety of materials, many of which degrade very slowly, making the problem increasingly serious. Even if we stopped producing waste today, the impacts of marine litter would persist for many years.
Around 70% of all marine litter is plastic. The remaining 30% includes materials such as glass, paper, metal, textiles, and more. However, the type and quantity of litter entering the ocean can vary significantly between regions, often influenced by socio-economic factors such as urbanisation, tourism, and fishing activities.
Of the litter we see on our beaches represents only a small fraction of all the waste in the ocean.
Of marine litter floats on the surface or is suspended in the water column (deeper than 40 cm).
Lies on the seafloor, out of sight.
Of all marine litter is made up of plastics.
Consists of other materials such as glass, paper, metal, textiles, and more.
- When Does Plastic Become a Problem?
Most of the products we consume or use daily are packaged in plastic, a material designed
to last forever, however often thrown away almost immediately. This throwaway mindset is a relatively recent global phenomenon. Just a few generations ago, products were packaged in reusable containers or recyclable materials like glass, metal, and paper.Glass jars, for example, were commonly reused to store goods like vegetables or sweets. However, the need to transport larger quantities of goods with less weight led industries to choose plastic packaging, which is lighter than glass and therefore more economical for transport. As a result, the consumption of plastic-packaged goods increased significantly.
Today, landfills and beaches are filled with discarded plastic packaging and single-use items that are not valued for their short life span. The short-term convenience of our daily choices is becoming a long-term environmental problem. Plastic that is not recycled or sent to landfill often ends up in the ocean — carried there by extreme weather events such as floods, or transported via river currents.
- How Much Plastic Is in the Ocean?
Although extensive research is being carried out to answer this question, it is currently not possible to estimate the exact amount of plastic in the ocean. As plastic breaks down, it can reach microscopic sizes — and even though it becomes invisible to the naked eye, it is still present and persistent in the marine environment.
- Marine Litter – A Global Problem
Oceans are dynamic systems, shaped by complex networks of currents that move water across the entire planet. These ocean currents are influenced by Earth’s rotation, wind patterns, and differences in water density. Temperature also plays a key role, with currents classified as either warm or cold. Where ocean currents converge, due to the Coriolis effect, large circular systems called gyres often form. These ocean gyres are rotating currents that create zones where materials tend to accumulate. The image below shows the global ocean currents and gyres. As water begins to circulate in these gyres, it’s common to find both organic debris (e.g. seeds) and inorganic materials (especially plastics) concentrated in these areas. One of the most studied cases is the North Pacific Gyre, where Captain Charles Moore reported striking findings in waters thousands of kilometres from the nearest coastline. Plastic was found in much greater abundance than plankton, the microscopic organisms that form the base of the marine food chain. His discovery, often referred to as the “plastic soup”, revealed just how deeply marine pollution is influenced by human activities along coastlines, and how far its impact can reach into the open ocean.