Battle of the Bags: Are Plastic Bags an Environmental Threat?

By Jon Entine
September 2, 2009

When plastic bags were introduced decades ago, they were touted as light, cheap, and reusable–an environmental improvement over wasteful paper bags. Of course it didn’t turn out that way. Billions are dispensed of each year. And according to some environmentalists, rather than an improvement over paper bags, they represent everything that’s wrong with our consumerist culture: they’re made of petrochemicals, a non-renewable resource; disposed of in landfills, they’re not biodegradable; children can swallow them; and they can kill marine life.

Prominent activist NGOs such as Greenpeace, Environmental Defense Fund, Earth Resource Foundation, and Natural Resource Defense Council have taken strong stances against them. With the sustainability mania in full swing, corporations have responded reflexively. IKEA and Whole Foods discontinued plastic bags in their stores in 2008. Wal-Mart, long the target of environmentalists, is teaming with the EDF in a so-called Global Plastic Shopping Bag Waste Reduction Program, which it says will reduce the number of shopping bags by 9 million by 2013.

Cities from San Francisco to Mexico City to Washington, DC to Fairbanks have moved to tax them or ban their use. Earlier this summer, the North Carolina state Senate banned plastic bags in the Outer Banks area and Malibu, California has taken steps to eliminate plastic bags from the beachfront community. Even China has hopped on the bandwagon, adopting a ban on the free distribution of thin plastic bags more than a year ago.

And now the United Nations is putting its stamp on the movement. A top official for the UN Environment Program has called for a global ban on plastic bags. “There is simply zero justification for manufacturing them anymore, anywhere,” said Achim Steiner, executive director of UNEP.

Reducing waste is a good thing. But the real question is: In the zeal to demonize plastic bags, are we trading one ecological problem for another? Does this campaign make environmental sense? Are plastic bags really more harmful to the environment than paper bags, one of the favorite alternatives touted by environmentalists?

The Story Behind the Story

Paper or plastic? It’s a great debate, one that each of us confronts every time we go through the checkout at the local grocery store.

In August, Seattle, thought of as one of the country’s most liberal cities, rejected a tax on plastic bags. Why? Besides the concern about adding financial burdens during a recession, opponents argued, effectively, that the alternative, paper bags, are not quite what they cracked up to be as environmental windfalls.

NGOs and environmental activists have long argued the virtues of paper bags, highlighting the supposed threat plastic bags pose to marine life. According to Greenpeace, “over a million sea-birds and one hundred thousand marine mammals and sea turtles are killed each year by ingestion of plastics or entanglement,” including plastic bags. For example, it’s known that some sea turtles have mistaken plastic bags for jellyfish. In 2002 a minke whale that washed up on a beach in Normandy was found to have 800 grams of plastic and other packaging in its stomach.

With those high profile images in mind, the UN joined the anti-plastic bag campaign. In an April 2009 study, “Marine Litter: A Global Challenge,” UNEP reported that plastic bags made up 9.4 percent of the world’s coastal litter. “Litter, like thin film use plastic bags which choke marine life, should be banned or phased out rapidly everywhere,” concluded UNEP. Although its recent worldwide ban on plastic bags has no real claim on the laws of participating countries and cannot enforce its new policy, UNEP is providing education and program coordination on marine conservation and cleanup.

But when you probe beneath the surface, the “facts” concerning the dangers of plastic bags to marine life are murky. According to many scientists, they are not the marine villain they’ve been made out to be. The danger for water mammals and fish comes from other sources. “Plastic bags don’t figure into the entanglement,” says David Laist of the British science education project Sense and Science. “The main culprits are fishing gear, ropes, lines, and strapping bands. Most mammals are too big to get caught up in a plastic bag.”

Even one of Greenpeace’s top scientists acknowledges the issue has been distorted by misinformation and hysteria. “It’s very unlikely that many animals are killed by plastic bags.” says Greenpeace marine biologist David Santillo. “The evidence shows just the opposite.  We are not going to solve the problem of waste by focusing on plastic bags.”

In fact, in the UNEP’s International Coastal cleanup report states that while plastic bags made up 9.4 percent of the litter, fishing lines represented 46.8 percent of the total trash haul.

Is Plastic Advantageous?

The benefits of the alternative of choice to plastic bags, paper bags, are also wildly exaggerated. There is growing evidence that the production, use and disposal of plastic bags put less burden on natural resources than paper bags. According to the United States Environmental Protection Agency (EPA), it takes 70 percent less energy to produce a plastic bag than a paper one, and a pound of plastic bags takes 91 percent less energy to recycle than a pound of paper bags.

Life cycle analysis—the state of the art way of evaluating a product’s environmental footprint—also leans toward plastic over paper. Comparatively, plastic bags require less energy to produce. The total environmental impact depends upon the efficiency of operations at each stage of production and the effectiveness of environmental protection measures at manufacturing facitilites. Paper is produced from trees, 14 million of which are used each year in paper bag production; environmental impacts include extracting timber and processing it for paper products. Plastic bags are of course produced from oil, with its own set of environmental consequences.

Both paper and plastic bags have to be transported to stores by truck, which require energy and creates emissions. It would take approximately seven trucks to transport the same number of paper bags as can be transported by a single truck full of plastic bags.

Plastic bags were damned for years because they were not disposable, but new technologies allow them to be recycled. Recycling rates for plastic bags exceed 30% in some Asian and European countries, notably Germany, which is one reason why they haven’t rushed to abandon plastic bags. Some cities in the U.S. are now recycling plastic bags, and the trend is accelerating.

What happens in landfills, where most bags, paper and plastic, end up? Paper bags supposedly offer environmental advantages because they decompose so quickly, but they don’t in landfills. Although plastics do not biodegrade, modern landfills are designed in such a way that nothing biodegrades, because the waste is isolated from air and water in order to prevent groundwater contamination and air pollution. Land-filled plastic bags are more environmentally benign than paper because they require less space. In fact, paper occupies approximately half of overall landfill volume. Plastics, including bags, can be compressed to less than one half of their volume. As manufacturers have continued to make their plastic packaging thinner and lighter to save materials, the percentage of landfill volume taken up by plastics has remained steady since 1970, even as plastics have become more widely used.

One favorite alternative offered by environmentalists, and even hyped by the EPA, is the use of biodegradable plastic bags made from corn starch, such as Symphony Plastics’ d2w bag, which is “totally degradable” in as short as 60 days. That short life won’t do much good if they’re locked in landfills, rather than specialized composting bins, which are a rarity. And according to the European Plastics Recyclers, the additives contained in biodegradable plastics may end up polluting water supplies. The whole issue of biodegradiblity is likely overstated.

Final Word

Although bans have been initiated in a few US cities most Americans view the issue with indifference. Baltimore backed out on a bag fee earlier this year, and a week-old bag ban in Philadelphia was rescinded. In August, voters in Seattle, one of America’s most liberal cities, soundly rejected a bag tax promoted by anti-plastic bag activists. But indifference is not just a US thing. The heralded ban in China is being ignored by as much as 80 percent of stores, particularly in rural areas, according to a recent survey.

The debate between plastic and paper is by no means over. One thing is clear, however: plastic bags aren’t the evil they’re made out to be by many NGOs and UNEP, and paper bags aren’t quite the panacea.

“It depends on what environmental issues you see as being more important,” says Lisa Mastny, who directs the consumption project at the Worldwatch Institute, an environmental group. “The things you can see in your daily life tend to create more of an emotional response than the things that are in the background.”