A 2015 study published in Science estimated that 4.8 to 12.7 million metric tons of plastic waste enter our oceans annually, with the origin of marine litter closely related to populations concentrated near oceans and the quality of waste management systems. Although research shows the environmental cost of using plastics is nearly four times less than the cost that would result if plastics were replaced with other materials in certain applications, marine litter is still a big impact on the environment and must be reduced. In March 2011, leaders from 47 plastics associations across the globe launched a Declaration of the Global Plastics Associations for Solutions on Marine Litter, a public commitment to help tackle the global problem of plastic litter in the marine environment. These industry leaders identified six areas for initiatives aimed at contributing to sustainable solutions: education, research, public policy, sharing best practices, plastics recycling/recovery, and plastic pellet containment. By December 2015, 260 projects had been planned, were underway, or completed. The projects vary widely, from enhanced recycling to beach clean ups, and from global research to awareness and education campaigns; and include examples of innovative approaches to private sector engagement.