Paper Grocery Bags Require More Energy Than Plastic Bags

Paper vs. plastic debate shows how good environmental intentions coupled with bad information lead us astray

Whole Foods Market won’t offer plastic shopping bags at their stores after Earth Day this year. It is a savvy move for the upscale natural foods retailer, who estimates that by the end of the year the policy will have averted use of 100 million new plastic grocery bags at their 270 stores. It won’t save the company any money-since the paper and multi-use bags that will replace plastic bags at their stores cost more to manufacture, stock and handle-but it is a savvy public relations move that will likely help to soothe the guilty environmental consciences of devoted Whole Foods shoppers who, like most Americans, believe paper bags are environmentally superior to plastic bags.

Unfortunately, the reality is that paper isn’t better than plastic.

One hundred million new plastic grocery bags require the total energy equivalent of approximately 8300 barrels of oil for extraction of the raw materials, through manufacturing, transport, use and curbside collection of the bags. Of that, 30 percent is oil and 23 percent is natural gas actually used in the bag-the rest is fuel used along the way. That sounds like a lot until you consider that the same number of paper grocery bags use five times that much total energy. A paper grocery bag isn’t just made out of trees. Manufacturing 100 million paper bags with one-third post-consumer recycled content requires petroleum energy inputs equivalent to approximately 15,100 barrels of oil plus additional inputs from other energy sources including hydroelectric power, nuclear energy and wood waste.

Making sound environmental choices is hard, especially when the product is “free,” like bags at most grocery stores. When the cashier rings up a purchase and bags it in a paper bag, the consumer doesn’t see that it took at least a gallon of water to produce that bag (more than 20 times the amount used to make a plastic bag), that it weighed 10 times more on the delivery truck and took up seven times as much space as a plastic bag in transit to the store, and will ultimately result in between tens and hundreds of times more greenhouse gas emissions than a plastic bag.

Biodegradable bags don’t fare much better than paper bags; in a recent life cycle analysis, one type of compostable plastic bag was found to use somewhat less total energy and generate less solid waste, but represent more fossil fuel use, greenhouse gas emissions, and fresh water use than the comparable paper bag.

Part of the invisible cost of shopping bags is passed down to consumers as retailers recoup the price they pay for the bags-pennies in the case of plastic, a nickel or a dime for paper bags (ones with handles cost more), and the same or more again for biodegradable plastic bags. Costs like greenhouse gas emissions and air or water pollution might eventually be captured in a carbon tax, cap-and-trade scheme, or regulatory fee (again, ultimately passed down to consumers, whether they are aware of it or not). Still other costs are borne by the public (e.g. litter pick-up) or in less calculable ways (e.g. diminished aesthetic values or impacts to marine animals).

The good news is that, given a choice between plastic, paper and multi-use grocery bags, most people make the best available environmental choice: whichever bag they are most likely to reuse. In an informal online MSNBC survey last month, 38 percent of respondents said reusability was the most important factor in choosing what type of grocery bag to use. The plurality, 41 percent, choose plastic. Twenty-eight percent reported that environmental concerns were their top consideration and-unfortunately, given the comparative life cycle analyses-56 percent believed that paper is more “environmentally friendly.”

The vast majority of people reuse “single-use” plastic bags for household tasks like bagging garbage and cleaning up messes. Ireland’s plastic bag tax, initiated in 2002 to combat the aesthetic impacts of litter on tourism, virtually eliminated the use of the targeted bags but also resulted in a 77 percent increase in the sale of kitchen garbage bags. San Francisco’s first-in-the-nation ban on non-biodegradable plastic bags last year surely has had similar rebound affects.

Nationwide, the most recent Environmental Protection Agency data show recycling rates for broad categories that include paper and plastic grocery bags to be 25 and 9 percent, respectively. The recycling rate for plastic is growing quickly under the pressure of new mandates and markets. The actual amount recovered nationwide doubled between 2005 and 2006. Most of the plastic bags recycled are reclaimed for use in the United States or Canada to manufacture decking, railing and fencing which replace the use of virgin forest products.

For those bags that aren’t recycled, misconceptions about plastic and paper bags follow them all the way to their graves. In a landfill, paper bags, petroleum-based plastic bags and even degradable plastic bags share roughly the same fate. Modern landfills are managed for stability, not decomposition. Plastic bags can be better in a landfill because their compact size takes up the least space and, as opposed to biodegradable bags, they release zero greenhouse gas emissions.

Reusable shopping bags may be the norm at Whole Foods a year from now, but they’re not for everyone in every circumstance. A multi-use plastic or durable bag is environmentally and economically cost-effective only if it is actually used multiple times. Some of these bags are recyclable or compostable, others are not. The basic principles of conservation apply here: the greenest individual choice is the one that results in the greatest actual reduction, reuse and recycling.

Less than a year after a law requiring grocery stores to accept plastic bags for recycling took effect, lawmakers in California are now proposing mandatory reductions in plastic bag use and up to a 25-cent charge for plastic grocery bags statewide.

Those who are cognizant of the environmental realities of the paper versus plastic debate, but nevertheless believe providing complimentary plastic bags at grocery stores should be illegal, cling optimistically to the idea that plastic grocery bags can be erased from the environmental equation without unintended consequences. At present, the only honest assessment is that a plastic bag ban is a de facto paper bag mandate, and increased use of paper bags means an increase in environmental ills including air and water pollution, greater energy and water use and higher greenhouse gas emissions.

In a sense, the persistent view of plastic bag use as emblematic of the nation’s progress on environmental issues is right for the wrong reasons. It shows how far good intentions coupled with bad information can lead us astray.