8
million metric tons of plastic enter the oceans per year
The
192 countries with a coast bordering the Atlanta, Pacific and Indian oceans,
Mediterranean and Black seas produced a total of 2.5 billion metric tons of
solid waste. Of that, 275 million metric tons was plastic, and an estimated 8
million metric tons of mismanaged plastic waste entered the ocean in 2010. Credit:
Lindsay Robinson/UGA
A plastic grocery bag cartwheels down the beach until a gust of
wind spins it into the ocean. In 192 coastal countries, this scenario plays out
over and over again as discarded beverage bottles, food wrappers, toys and
other bits of plastic make their way from estuaries, seashores and uncontrolled
landfills to settle in the world's seas.
How much mismanaged plastic waste is making its way from land to
ocean has been a decades-long guessing game. Now, the University of Georgia's
Jenna Jambeck and her colleagues in the National Center for Ecological Analysis
and Synthesis working group have put a number on the global problem.
Their study, reported in the Feb. 13 edition of the journal Science, found between 4.8
and 12.7 million metric tons of plastic entered the ocean in 2010 from people
living within 50 kilometers of the coastline. That year, a total of 275 million
metric tons of plastic waste was generated in those 192 coastal countries.
Jambeck, an assistant professor of environmental engineering in the UGA College of Engineering and the study's lead author, explains the amount of plastic moving from land to ocean each year using 8 million metric tons as the midpoint: "Eight million metric tons is the equivalent to finding five grocery bags full of plastic on every foot of coastline in the 192 countries we examined."
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They began by looking at all debris entering the ocean from
land, sea and other pathways. Their goal was to develop models for each of
these sources. After gathering rough estimates, "it fairly quickly emerged
that the mismanaged waste and solid waste dispersed was the biggest contributor
of all of them," he said. From there, they focused on plastic.
"For the first time, we're estimating the amount of plastic
that enters the oceans in a given year," said study co-author Kara
Lavender Law, a research professor at the Massachusetts-based Sea Education
Association. "Nobody has had a good sense of the size of that problem
until now."
The framework the researchers developed isn't limited to
calculating plastic inputs into the ocean.
"Jenna created a framework to analyze solid waste streams
in countries around the world that can easily be adapted by anyone who is
interested," she said. "Plus, it can be used to generate possible
solution strategies."
Plastic pollution in the ocean was first reported in the scientific
literature in the early 1970s. In the 40 years since, there were no rigorous
estimates of the amount and origin of plastic debris making its way into the
marine environment until Jambeck's current study.
Part of the issue is that plastic is a relatively new problem
coupled with a relatively new waste solution. Plastic first appeared on the
consumer market in the 1930s and '40s. Waste management didn't start developing
its current infrastructure in the U.S., Europe and parts of Asia until the
mid-1970s.
Prior to that time, trash was dumped in unstructured landfills--Jambeck has vivid memories of growing up in rural Minnesota, dropping her family's garbage off at a small dump and watching bears wander through furniture, tires and debris as they looked for food.
Prior to that time, trash was dumped in unstructured landfills--Jambeck has vivid memories of growing up in rural Minnesota, dropping her family's garbage off at a small dump and watching bears wander through furniture, tires and debris as they looked for food.
"It is incredible how far we have come in environmental
engineering, advancing recycling and waste management systems to protect human
health and the environment, in a relatively short amount of time," she
said. "However, these protections are unfortunately not available equally
throughout the world."
Some of the 192 countries included in the model have no formal
waste management systems, Jambeck said. Solid waste management is typically one
of the last urban environmental engineering infrastructure components to be
addressed during a country's development. Clean water and sewage treatment
often come first.
"The human impact from not having clean drinking water is
acute, with sewage treatment often coming next," she said. "Those
first two needs are addressed before solid waste, because waste doesn't seem to
have any immediate threat to humans. And then solid waste piles up in streets
and yards and it's the thing that gets forgotten for a while."
As the gross national income increases in these countries, so
does the use of plastic. In 2013, the most current numbers available, global
plastic resin production reached 299 million tons, a 647 percent increase over
numbers recorded in 1975. Plastic resin is used to make many one-use items like
wrappers, beverage bottles and plastic bags.
With the mass increase in plastic production, the idea that
waste can be contained in a few-acre landfill or dealt with later is no longer
viable. That was the mindset before the onslaught of plastic, when most people
piled their waste--glass, food scraps, broken pottery--on a corner of their
land or burned or buried it.
Now, the average American generates about 5 pounds of trash per day with 13% of that being plastic.
Now, the average American generates about 5 pounds of trash per day with 13% of that being plastic.
But knowing how much plastic is going into the ocean is just one
part of the puzzle, Jambeck said. With between 4.8 and 12.7 million metric tons
going in, researchers like Law are only finding between 6,350 and 245,000
metric tons floating on the ocean's surface.
"This paper gives us a sense of just how much we're
missing," Law said, "how much we need to find in the ocean to get to
the total. Right now, we're mainly collecting numbers on plastic that floats.
There is a lot of plastic sitting on the bottom of the ocean and on beaches
worldwide."
Jambeck forecasts that the cumulative impact to the oceans will
equal 155 million metric tons by 2025. The planet is not predicted to reach
global "peak waste" before 2100, according to World Bank
calculations.
"We're being overwhelmed by our waste," she said.
"But our framework allows us to also examine mitigation strategies like
improving global solid waste management and reducing plastic in the waste
stream. Potential solutions will need to coordinate local and global
efforts."
Story
Source:
The above story is based on materials provided by University of Georgia. The original
article was written by Stephanie Schupska. Note:
Materials may be edited for content and length.
Journal
Reference:
J. R. Jambeck, R. Geyer, C. Wilcox, T. R. Siegler, M. Perryman,
A. Andrady, R. Narayan, K. L. Law. Plastic
waste inputs from land into the ocean. Science, 2015; 347 (6223):
768 DOI: 10.1126/science.1260352
Cite
This Page:
University of Georgia. "Magnitude of plastic waste going
into the ocean calculated: 8 million metric tons of plastic enter the oceans
per year." Science Daily,
12 February 2015.
<www.sciencedaily.com/releases/2015/02/150212154422.htm>.