Our estimate of plastic waste entering the ocean is one to three orders of magnitude greater than the reported mass of floating plastic debrisin high-concentration ocean gyres and also globally (14–17). Although these ocean estimates represent only plastics that are buoyant in seawater (mainly polyethylene and polypropylene), in 2010 those resins accounted for 53% of plastic production in North America and 66% of plastic in the U.S. waste stream (4, 18). Because no global estimates exist for other sources of plastic into the ocean (e.g., losses from fishing activities or at-sea vessels, or input from natural disasters), we do not know what fraction of total plasticinput our land-based waste estimate represents