“Producing plastics from fossil fuels emits a lot of carbon dioxide into the atmosphere, which contributes to warming the planet. An April study by researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory estimates that in 2019 “global production of primary plastics generated about 2.24 gigatonnes of carbon dioxide equivalent,” which represents 5.3 percent of total global greenhouse gas emissions. So switching to plastic alternatives would help slow man-made global warming, right?
Not so fast, says a new study in Environmental Science & Technology, which finds that “replacing plastics with alternatives is worse for greenhouse gas emissions in most cases.” The European researchers report that in “15 of the 16 applications a plastic product incurs fewer greenhouse gas emissions than their alternatives.”
The researchers considered emissions from production, transportation, use, and end-of-life disposal, including landfilling, incineration, recycling, and reuse. Calculating the product life cycles, plastic products release 10 percent to 90 percent fewer emissions than do plausible alternatives—often because it takes less energy to make and transport them.
Take the perennial plastic vs. paper conundrum about grocery bags. In the U.S., more than 500 cities and 12 states have banned plastic grocery bags. However, the researchers find that plastic grocery bags emit 80 percent fewer greenhouse gases than paper bags. Producing paper bags emits three times the greenhouse gases of plastic ones, and transportation emissions are higher because paper bags weigh six times more than plastic bags. Additionally, paper bags emit globe-warming methane as they rot in landfills.
Alternatives to plastic bottles are aluminum cans and glass bottles. Even though aluminum cans are often recycled, the researchers find that over their life cycle, they emit twice as many greenhouse gases as plastic bottles. Glass bottles emit three times more.”