Reshaping the plastic lifecycle into a circle

Date:
November 30, 2021
Source:
University of Pittsburgh
Summary:
New research gives a bird's-eye view of the scale of plastic
creation globally, tracing where it's produced, where it ends up,
and its environmental impact.



FULL STORY ==========================================================================
In 1950, 2 million metric tonnes of new plastic was produced
globally. In 2018, the world produced 360 million metric tonnes of
plastics. Because of their low cost, durability and versatility, plastics
are everywhere-including in the environment-and only 9 percent of the
plastic ever generated has been recycled.

The vast majority ends up in landfills, where its slow degradation
allows it to accumulate, while pervasive microplastics have been found everywhere, from inside living bodies to the bottom of the ocean.


==========================================================================
"At our current rate of plastic waste generation, increasing waste
management capacity will not be sufficient to reach plastic pollution
goals alone," said Vikas Khanna, associate professor of civil and
environmental engineering at the University of Pittsburgh Swanson School
of Engineering. "There is an urgent need to take actions like limiting
global virgin plastic production from fossil fuels and designing products
and packaging for recyclability." New research led by Khanna gives a bird's-eye view of the scale of plastic creation globally, tracing where
it's produced, where it ends up, and its environmental impact.

The researchers found the greenhouse gas emissions associated with the production of plastic in 2018 staggering: 170 million metric tonnes
of primary plastics were traded globally in 2018, with associated
greenhouse gas emissions accounting for 350 million metric tonnes of
CO2 equivalent-about the same amount produced by nations like Italy and
France in a year.

"And if anything, our estimation is on the lower end. Converting primary plastic resins into end use products will result in additional greenhouse
gases and other emissions," warned Khanna.

The work was recently published in the journal ACS Sustainable Chemistry
& Engineering.



==========================================================================
"We know plastics are a problem, and we know keeping materials in a
circular economy instead of the take-make-waste model we're used to is
a great solution," said Khanna. "But if we don't have an understanding
of the current state of the system, then it's hard to put numbers to
it and understand the scale. We wanted to understand how plastics are
mobilized across geographical boundaries." Since international trade
plays such a critical role in making material goods available, including plastics, the researchers applied network theory to data from the UN
Comtrade Database to understand the role of individual countries, trade relationships between countries, and structural characteristics that
governed these interactions. The global primary plastic trade network
(GPPTN) that they created designated each country as a "node" in the
network and a trade relationship between two countries as an "edge,"
allowing them to determine the critical actors (countries) and who is
making the biggest impact.

The researchers examined 11 primary thermoplastic resins that make up
the majority of plastic products. They found that a majority of the most influential nodes in the model are exporting more plastics than they
import: Saudi Arabia is the leading exporter, followed by the U.S.,
South Korea, Germany and Belgium.The top five importers of primary
plastic resins are China, Germany, the U.S., Italy and India.

In addition to the greenhouse gas emissions, the energy expended in the
GPPTN is estimated to be the equivalent of 1.5 trillion barrels of crude
oil, 230 billion cubic meters of natural gas, or 407 metric tonnes of
coal. The carbon embedded in the model is estimated to be the carbon
equivalent of 118 million metric tonnes of natural gas or 109 million
metric tonnes of petroleum.

"The results are particularly important and timely, especially in light
of the recent discussions during Conference of the Parties (COP26) in
Glasgow and the importance of understanding where emissions are coming
from in key sectors," said co-author Melissa Bilec, Co-director of Mascaro Center for Sustainable Innovation and William Kepler Whiteford Professor
of Civil and Environmental Engineering. "The collaboration with Dr. Khanna
and his lab allows us to learn new systems-level modeling techniques as
we converge towards understanding solutions to our complex challenges."
This paper, "Quantifying Energy and Greenhouse Gas Emissions Embodied in
Global Primary Plastic Trade Network," is supported by the NSF convergence research project on the circular economy, which is led by Bilec.

Using more recycled plastics instead of creating new resins that
eventually make their way to landfills would be substantially better for
the environment; however, financial and behavioral barriers both need
to be addressed before a true circular economy for plastics can become
a reality.

"Even though emerging chemical recycling techniques promise to
recover more material in an economically and environmentally sound
way, we need to make it so that using recycled materials is as
cost-effective as using virgin plastic resins," said Khanna. "Our
next step is to understand the interaction between the GPPTN and
the plastic waste trade network to identify the opportunities
where investment could encourage a circular plastics economy." ========================================================================== Story Source: Materials provided by University_of_Pittsburgh. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Joseph Zappitelli, Elijah Smith, Kevin Padgett, Melissa M. Bilec,
Callie
W. Babbitt, Vikas Khanna. Quantifying Energy and Greenhouse Gas
Emissions Embodied in Global Primary Plastic Trade Network. ACS
Sustainable Chemistry & Engineering, 2021; 9 (44): 14927 DOI:
10.1021/ acssuschemeng.1c05236 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211130112512.htm

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