In the past thirty years, the use of plastics and other synthetic materials has expanded at a rapid pace. As new uses for these materials have been developed, applied, and made available to more people, the quantity of plastic debris entering the marine environment has undergone a corresponding increase. The accumulating debris poses increasingly significant threats to marine mammals, seabirds, turtles, fish, and crustaceans. Tiny floating particles also resemble zooplankton, which can lead filter feeders to consume them and cause them to enter the ocean food chain.

Due to the circulation of currents in the Oceans known as Gyres, the accumulations of debris are formed into huge floating 'islands' of rubbish. Action By Sea is focussing on the North Atlantic Gyre.

The North Atlantic Garbage Patch is an area of marine debris found floating within the North Atlantic Gyre, originally documented in 1972. The patch is estimated to be hundreds of kilometers across in size, with a density of over 200,000 pieces of debris per square kilometer