An estimated 414 million pieces of anthropogenic debris - including plastics, foam, metal and glass, weighing 238 tonnes - were distributed across the remote Cocos (Keeling) Islands (CKI) in 2017. The findings, reported in Scientific Reports, are the result of the first, comprehensive survey of debris on CKI, a group of 27 small islands located 2,100 km off the northwest coast of Australia.

Jennifer Lavers and colleagues conducted a comprehensive survey in 2017 of macro- and micro-debris on 25 beaches on seven islands, representing 88% of the CKI landmass. The authors found that micro-debris - small, broken-down fragments of larger items - made up more than 60% of all debris present on CKI beaches. Shoes and single-use or disposable consumer items, such as food packaging, drink bottles, straws, and toothbrushes, made up nearly 25% of identifiable debris. Plastic items accounted for over 95% of all debris recorded, followed by foam (3.06%) and other debris types (0.63%).

The researchers estimate that 338,355,473 debris items may be buried 1-10 cm below the beach surface, which is 26 times greater than the amount of debris visible on the surface (an estimated 12,868,379 items). This suggests that previous global debris surveys, the majority of which were focused solely on surface debris, may have considerably underestimated the scale of debris accumulation.

The authors suggest that a multi-pronged approach is urgently needed to prevent the entry of more plastic into the ocean, including investment in strategies that limit plastic production and consumption, widespread bans on single-use items and effective waste management.