Plastic litter is one of the most significant problems facing the world's marine environments. Yet in the absence of a coordinated global strategy, an estimated 20 million tons of plastic litter enter the ocean each year.

A new report by authors from UCLA School of Law's Emmett Center on Climate Change and the Environment and UCLA's Institute of the Environment and Sustainability explores the sources and impacts of plastic marine litter and offers domestic and international policy recommendations to tackle these growing problems - a targeted, multifaceted approach aimed at protecting ocean wildlife, coastal waters, coastal economies and human health.

"Stemming the Tide of Plastic Marine Litter: A Global Action Agenda," the Emmett Center's most recent Pritzker Environmental Law and Policy Brief, documents the devastating effects of plastic marine litter, detailing how plastic forms a large portion of our waste stream and typically does not biodegrade in marine environments.

Plastic marine litter has a wide range of adverse environmental and economic impacts, from wildlife deaths and degraded coral reefs to billions of dollars in cleanup costs, damage to sea vessels, and lost tourism and fisheries revenues. The brief describes the inadequacy of existing international legal mechanisms to resolve this litter crisis, calling on the global community to develop a new international treaty while also urging immediate action to implement regional and local solutions.

"Plastic marine litter is a growing global environmental threat imposing major economic costs on industry and government," said report co-author Mark Gold, an associate director of the Institute of the Environment and Sustainability. Marine plastic pollution slowly degrades and has spread to every corner of the world's oceans, from remote islands to the ocean floor.

Voluntary half-measures are not preventing devastating global impacts to marine life, the economy and public health. Although there is no one panacea, we have identified the top 10 plastic pollution-prevention actions that can be implemented now to begin drastically reducing plastic marine litter."

In "Stemming the Tide of Plastic Marine Litter," the authors review the universe of studies, policies and international agreements relevant to the problem and provide a suite of recommendations to achieve meaningful reductions in plastic marine litter.

The report's "Top 10" list of recommended actions includes a new international treaty with strong monitoring and enforcement mechanisms; domestic and local regulatory actions, such as bans of the most common and damaging types of plastic litter; extended producer-responsibility programs; and the creation of an "ocean friendly" certification program for plastic products.

"Because global mismanagement of plastic is fueling the growing marine litter problem, policy responses are needed at all levels, from the international community of nations down to national and local communities," said report co-author Cara Horowitz, executive director of the Emmett Center on Climate Change and the Environment.

"We can act now to rapidly scale up effective policies and programs to address plastic marine litter. And hopefully, international collaboration to reduce plastic litter will lay a foundation for broader cooperation on other significant issues affecting the health of our oceans."

Plastic marine litter has its origins in both land- and ocean-based sources, from untreated sewage and industrial and manufacturing sites to ships and oil and gas platforms. Pushed by the natural motion of wind and ocean currents - often over long distances - the litter is present in oceans worldwide, as well as in sea floor sediment and coastal sands.

As the particles break down and disperse, they have a wide range of adverse environmental, public health and economic consequences with the potential to kill wildlife, destroy natural resources and disrupt the food chain.