A new study published in Nature Sustainability by researchers at the Swiss university ETH Zurich demonstrates that the impact of plastics production on human health and climate is greater than previously thought, with plastics accounting for an estimated 4.5 percent of global greenhouse gases.
The study, which analyzed the global plastics value chain, found that coal-fired power plants contribute far more heavily to the carbon footprint of plastics than thought, mainly because more coal is being used for process heat, electricity and as a raw material in making resin.
Coal-based emissions from plastics production have quadrupled since 1995, the study said, with the greatest impact coming in newly industrialized countries such as China, India and South Africa.
To date, most research into the global environmental impact of plastics has been primarily focused on the disposal phase, with only a handful of studies examining the impact of plastics production on, for example, climate and air quality. To do so requires detailed information about supply chains and processes in order to be able to trace relevant material and energy flows.
"So far, the simplistic assumption has been that the production of plastics requires roughly the same amount of fossil resources as the amount of raw materials contained in plastics — particularly petroleum," said Livia Cabernard, a doctoral student at the Institute of Science, Technology and Policy (ISTP) at ETH Zurich. As a result, the relative significance of production versus disposal has been significantly underestimated, reseachers said.
Cabernard and researchers led by Stephan Pfister, senior scientist at the ISTP, and Stefanie Hellweg, ETH professor of ecological systems design at the Institute of Environmental Engineering, analyzed the climate and health impact of the global plastics supply chain from 1995 to 2015.
They calculated the greenhouse gas emissions generated across the life cycle of plastics, from fossil resource extraction, to processing and through to end of life, including recycling, incineration and landfill, and used a new method to map supply chains developed by Cabernard.
The study said the global carbon footprint of plastics has doubled since 1995, reaching 2 billion tonnes of CO2 equivalent in 2015. This represents 4.5 percent of global greenhouse gas emissions, and is more than previously thought.
Researchers said the fast-expanding plastics production activities in coal-based, newly industrialized countries such as China, India, Indonesia and South Africa are the main cause of the growing carbon footprint of plastics.
"The plastics-related carbon footprint of China's transport sector, Indonesia's electronics industry and India's construction industry has increased more than 50-fold since 1995," Cabernard said.
The energy and process heat needed for the production of plastics in these countries comes primarily from the combustion of coal. A small amount of coal is also used as a raw material for plastics.
Globally, coal-based emissions from plastics production have quadrupled since 1995 and now account for nearly half of the global carbon footprint of plastics.
When coal is burned, it produces fine particles that accumulate in the air and that have been shown to cause asthma, bronchitis and cardiovascular disease.
As more and more coal is used for process heat and electricity, and as a raw material in the production of plastics materials, the negative effects on health also escalate.
This study said that between 1995 and 2015, the global health footprint of plastics from fine particulate air pollution increased by 70 percent, accounting in 2015 for the loss of approximately 2.2 million disability-adjusted life years, a metric used to account for both premature death and time lost to poor health.