“Plastics are the new coal,” explains Beyond Plastics. “Pollution from the plastics industry is one of the main causes of planetary warming,” reports The HillThe Natural Resources Defense Council says that “reducing plastic production is critical to combating climate change.”
The production of plastics from fossil fuels releases a lot of carbon dioxide into the atmosphere, which contributes to warming the planet. A study published in April 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 gigatons of carbon dioxide equivalent,” or 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 and Technologywhich finds that “replacing plastics with alternatives has, in most cases, worse impacts on greenhouse gas emissions.” The European researchers report that “in 15 out of 16 application areas, a plastic product causes fewer greenhouse gas emissions than the alternatives.”
The researchers took into account emissions from production, transport, use and end-of-life disposal, including landfilling, incineration, recycling and reuse. When calculating product life cycles, plastic products emit 10 to 90 percent fewer emissions than plausible alternatives – often because less energy is required to produce and transport them.
Take the eternal plastic-paper dilemma of shopping bags, for example. In the US, more than 500 cities and 12 states have banned plastic bags. However, researchers have found that plastic bags emit 80 percent fewer greenhouse gases than paper bags. The production of paper bags emits three times as many greenhouse gases as plastic bags, and transportation emissions are higher because paper bags weigh six times more than plastic bags. In addition, paper bags emit methane as they decompose in landfills, which contributes to global warming.
Alternatives to plastic bottles include aluminum cans and glass bottles. Although aluminum cans are often recycled, researchers found that they emit twice as many greenhouse gases as plastic bottles over their life cycle. Glass bottles emit three times more.
The United Nations is currently negotiating a global agreement to combat plastic pollution. One option being considered is a global ban on “short-lived and single-use plastic products.” This would likely include foam trays wrapped in thin plastic film used to package foods like pork and beef. The researchers compare this packaging to butcher paper and find that the use of butcher paper packaging, including emissions from production and food spoilage, emits 35 percent more greenhouse gases than plastics.
In municipal construction, polyvinyl chloride (PVC) sewer pipes are compared to concrete and ductile iron pipes. PVC pipes emit 45 percent fewer greenhouse gases than concrete pipes and 35 percent fewer than iron pipes. In residential construction, polyethylene pipes (the most commonly used commodity plastic) perform slightly better than copper pipes, emitting 3 percent fewer greenhouse gases.
Due to differences in raw materials, manufacturing, transportation and weight, plastic dining sets produce 50 percent fewer emissions than wooden dining sets. High-density polyethylene fuel tanks weigh so much less than steel ones that the fuel savings over their lifetime translate into 90 percent fewer greenhouse gas emissions. Polyethylene terephthalate/nylon carpets produce 80 percent fewer greenhouse gas emissions than wool carpets.
However, the researchers identified one case where the likely alternative to plastics emits fewer greenhouse gases: 55-gallon steel drums for industrial use. Because steel drums last longer and are typically recycled, they emit 30 percent fewer greenhouse gases over their lifetime than comparable plastic drums.
Conventional alternatives to current plastics are generally much worse in terms of greenhouse gas emissions, the study says. The researchers conclude that “any action or policy to reduce the impact of plastics needs to be carefully assessed to ensure that greenhouse gas emissions are not inadvertently increased by a switch to more emissions-intensive alternative materials.”
The good news is that some companies and researchers are developing plastics that are almost infinitely recyclable. Currently, UBQ Materials is converting unsorted household waste, including single-use plastics, into thermoplastics that can then be recycled up to five times – a process that reduces greenhouse gas emissions by more than 90 percent. In addition, researchers at Lawrence Berkeley National Laboratory have developed an “infinitely recyclable” bio-based plastic called polydiketoenamine that reduces greenhouse gas emissions by almost 98 percent compared to conventional plastics.
As the debate about plastics and their alternatives continues, it is important to consider the full environmental impact of our choices and promote innovations that actually reduce greenhouse gas emissions and protect our planet.
This article originally appeared in print under the headline “Plastics are better for the climate.”
