The theme for the 48th Earth Day is ending plastic pollution. The main concern of the Earth Day Network is the continuing accumulation of plastic trash in the world's oceans. The poster child of the plastic marine debris problem is the Great Pacific Garbage Patch that lies between Hawaii and California. Yachtsman Charles Moore identified the vast region—an area more than twice the size of Texas—of floating plastic bottles and lost fishing gear when he sailed through it in 1997.
Plastic marine debris is a classic example of the tragedy of the commons, in which users of unowned natural goods like the oceans have an incentive to overexploit and ruin them. In this case, tens of millions of free riding consumers do not suffer the costs of negligently discarding plastic products so that they end up washing into the oceans.
The spread of plastic marine debris is a big and growing problem. According to one recent estimate plastic now accounts for 95 percent of the human created waste that accumulates on shorelines, the sea surface and the seafloor. A 2014 report in the journal PLoS One estimated that a minimum of 5 trillion pieces of plastic weighing nearly 250,000 metric tons are afloat in the oceans. Researchers in a 2015 study in Science calculated that "275 million metric tons of plastic waste was generated in 192 coastal countries in 2010, with 4.8 to 12.7 million metric tons entering the ocean annually."
In a March Scientific Reports study, researchers who trawled through the Patch estimate that it contains at least 80,000 metric tons of plastic. Over three-quarters of the plastic debris mass is in pieces larger than 5?centimeters (2 inches) and at least 46 percent was comprised of fishing gear. Microplastics which are bits measuring between 0.05 and 0.5 centimeters (0.02 to 0.2 inches) accounted for 8 percent of the total mass but 94 percent of the estimated 1.8 trillion pieces floating in the area.
Drifting lost or discarded plastic fishing gear kills all kinds of sea life including seals, sharks, and turtles. Such ghost fishing may reduce catches in some fisheries by as much as 5 percent. Plastic in the oceans is harming some seabird and turtle populations that mistake the fragments as food. Currently, there is little evidence that consuming fish or shellfish that have ingested plastic bits is causing harm to people.
Interestingly, the 2014 PLoS One study noted that over time microplastic particles appear be disappearing from the ocean's surface. Plastics are broken up over time into every tinier pieces by the action of the waves and ultraviolet sunlight. The researchers suggest that the plastics might be being removed from the ocean by being borne down into the depths as they become encrusted with microscopic organisms; being excreted as heavier fecal pellets after being ingested by fish; and being biodegraded by microbes. Such microplastics may well end up in sediment on the ocean's floor.
So where is the plastic befouling the oceans coming from? The 2015 Science study estimated the flow of plastic waste that 20 populous coastal countries. The good news is that the United States is at the bottom of that list, dumping less than 1 percent of the plastics that end up in the oceans annually. In the United States, about 10 percent of plastic waste is recycled, 15 percent is burned to produce electricity or heat, and the rest is landfilled.
China is at the top of list of ocean plastic polluters, accounting for 28 percent the total amount of plastics thrown into the oceans each year. About 60 percent of plastics in the oceans are discarded by the fast growing East Asian economies of China, Indonesia, the Philippines, Vietnam, Sri Lanka, and Thailand. In fact, all 19 of the top 20 countries on the list of countries contributing to ocean plastic pollution are poor or middle-income countries. The main reasons these countries are such big contributors of plastic marine debris is that their consumers' garbage is uncollected and frequently ends up in open dumps.
There are two strategies for tackling such environmental tragedies: privatization or regulation. In the United States most wastes are picked up and disposed by city and commercial garbage haulers. Revenues for solid waste management industry were around $60 billion in 2016. In other words, most Americans take responsibility for their wastes by paying local taxes or fees to bury them in landfills, burn them, or recycle them. As a result relatively little plastic from the U.S. ends up in the oceans. Consequently, bans on plastic bags and water bottles in this country are largely instances of symbolic moral preening.
In their joint 2015 report Stemming the tide: Land-based strategies for a plastic-free ocean, the McKinsey Center for Business and the Environment and the Ocean Conservancy proposed several strategies aimed chiefly at getting the East Asian countries to better handle their plastic waste.
As a first step, the McKinsey researchers calculate that targeting about $5 billion per year toward improving garbage collection, recycling and building landfills would reduce the amount of plastics flowing into the oceans from those countries by 50 percent. The McKinsey report notes that in places with high waste collection rates, post-collection "leakage" is about 1 percent
In the longer term, as countries get richer they begin to clean up and take better care of their natural environments. Researchers call this process the Environmental Kuznets Curve in which air and water pollution begin to decline and forests to regrow once a country's citizens have reached certain income thresholds. As their citizens become wealthier the poor countries whose plastic wastes are befouling the oceans will shift from haphazard discards and open dumps to landfills and incineration. Plastic in the oceans is an open access commons tragedy, but one that will largely be resolved as global per capita incomes triple on average by 2050. Bans being promoted by the Earth Day Network would slightly reduce the amount plastic ocean debris, but the true solution to pollution is economic growth and increased wealth.