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Shoppers carry plastic bags in San Francisco's Chinatown in 2007.

Shoppers tote their wares in San Francisco's Chinatown just before that city's March 2007 ban on plastic bags. San Francisco approved the first anti-bag ordinance in the United States, but the idea is catching on around the world.

Photograph by David Paul Morris, Getty Images

Andrew Curry

For National Geographic News

Published May 3, 2011

This story is part of a special series that explores energy issues. For more, visit The Great Energy Challenge.

Archaeologists at work in the Egyptian desert call them “desert blossoms.” Beleaguered city dwellers refer to them as “urban tumbleweeds.” Flimsy, translucent, and so cheap to produce they seem almost free, plastic shopping bags are everywhere.

But a backlash is growing, due to the ubiquity of bag waste, and concern over the less visible toll—the energy that goes into their production.

(Related: The Green Guide)

Across the world, plastic bags have become a target for people who see them as both a pervasive symbol of a throw-away society and as a serious environmental problem. In India and Bangladesh, bags were banned in some cities after choking storm drains and contributing to deadly flooding. Bags that wind up in the ocean are deadly hazards for sea turtles and other fish, who mistake them for jellyfish. According to the U.N. Environmental Programme, 260 species are known to have accidentally eaten plastic or become entangled in it.

In the past decade, bans and taxes designed to reduce or eliminate bag consumption have swept the world. Certainly, the plastic industry continues to challenge these measures, strongly debating the environmental and energy benefits. But there is an irresistible appeal to bag action, especially in light of the difficulties that governments have had in enacting much more sweeping and complicated changes in energy and climate change policy.

Bottom line: Bag taxes and bans are simple, and they work.

Bags Full of Energy

Plastic shopping bags are typically made from polyethylene, which is produced when long chemical chains in processed natural gas or petroleum are combined together with pressure and heat.

There have been various efforts over the years to assess how much fuel is embedded in plastic bags, due to both the natural gas or petroleum feedstock and the energy of manufacture. The Australian government, in what some have viewed as one of the most comprehensive looks at the issue, concluded in 2002 that a year’s worth of weekly grocery trips, at 10 bags a trip, would result in embedded energy consumption of 210 megajoules—the equivalent of 1.75 gallons (6.6 liters) of gasoline, and emissions of 13 pounds (6.06 kilograms) of CO2.

It’s more difficult to say how this energy use adds up globally. Plastics overall account for only a small portion of fuel use; for example, plastics manufacturing accounts for only about 5 percent of U.S. petroleum consumption. Still, action to reduce the estimated 500 billion to 1 trillion plastic bags used worldwide each year is an opportunity to take a bite out of consumption—especially when this particular petroleum and gas product is so easily replaced with reusable cloth bags.

Besides, although the energy that goes into plastic bags is invisible, the litter caused by their improper disposal is inescapable.

So last year, although a bag tax was narrowly defeated in California, the coastal communities of Long Beach, San Francisco, and Carmel all banned the kinds of bags that were littering their beaches.

Bag bans and taxes are a hot topic across the United States, where more and more communities are debating whether to put them in place. Though such measures are most common at the community level, a handful of states have also tried to ban bags—most notably, Washington, D.C., and Oregon.

The Washington, D.C., tax, which went into effect last year, imposed a 5-cent charge on plastic and paper shopping bags. According to official estimates, the city’s 600,000 residents were using 22.5 million bags per month before the tax went into place. Afterwards, that number dropped to 4.6 million per month—an 80 percent drop that also brought the city $2.75 million in revenue for the year, a sum dedicated to river cleanup..

A similar strategy was used in Ireland, where authorities began charging consumers .15 euro (about 20 cents) per bag in March 2002. The charge could not be absorbed by stores, and had to appear on the customer’s receipt as a separate item. Proceeds went to support a special fund for environmental causes.

The impact was remarkable—and immediate. Within a few months, Irish shoppers went from using plastic bags at a rate of 328 per person per year to just 21. “It was a very dramatic fall-off,” says William Culbert, an official at Ireland’s Department of Environment, Heritage and Local Government. “Before the levy was introduced, some supermarkets recycled on a voluntary basis, and it wasn’t very successful. What made the difference was the levy.”

Culbert says the bag charge changed consumer behavior, and also shifted store practices. Stores began selling re-usable bags, and many discount stores stopped carrying bags entirely—instead putting out used cardboard packing boxes for customers to use. Today, bag buyers are usually spontaneous shoppers. “You always end up in a situation where you’re only buying a few items and you’ve left your bag in the car, or whatever,” Culbert says. Irish officials estimate the bag charge has resulted in the use of a billion fewer bags each year, and a recent survey showed the fee had overwhelming public support.

The plastic industry argues that bans and taxes are counterproductive. Instead, they argue that expanding recycling programs—like the bins outside many supermarkets that take plastic bags, shrink-wrap and other plastic packaging—is a better way to deal with the problem of plastic waste. The industry maintains that banning bags would discourage supermarkets from installing collection points for plastics, which would slow down recycling of not just bags but other plastics as well. “Bans and taxes eliminate collection infrastructure,” says Keith Christman, managing director of plastic markets at the American Chemistry Council, a lobbying group for the chemical industry, including plastics. “Why would a store put out recycling bins if there aren’t bags out there?”

Studies have shown that plastic bags can actually have a lower carbon footprint than paper, which is made from trees that need to be cut down, pulped, and heated at high temperatures.

Even reusable bags have come under scrutiny. Earlier this year, The Independent in London reported that a draft study by environmental authorities in the United Kingdom indicated that cotton bags might have a higher carbon impact than is often assumed; the benefits of reusable bags depend on how frequently consumers use them before discarding them.

And Christman says that for all their visibility and seeming ubiquity, bags represent a small fraction of waste—in the United States, only about half a percent of what is thrown away each day.

An Important Symbolic Step

But because of bags’ visibility, their symbolic importance is huge. And environmental activists suggest that voluntary programs just don’t cut it. “Yes, there are recycling programs,” says Daniella Dimitrova Russo, executive director of the Plastic Pollution Coalition. “No, they’re not enough—regardless of how many recycling programs you put in place, they aren’t effective.”

Instead, Russo says, people need to be nudged. Fifteen or 20 cents may not seem like a lot, but having to buy a bag is enough to make people stop and think. “Charging for bags puts the question in front of you,” Russo says. “It’s no longer something automatic—you have to make a choice.”

Some countries have gone even farther. In January, Italy banned single-use plastic shopping bags entirely. The country had been one of Europe’s heaviest consumers, representing a quarter of Europe’s total. Eva Alessi, head of sustainability for Italy’s World Wildlife Fund, says the ban—passed without a vote by the Italian Environment Ministry—was unpopular with retailers and consumers alike when it went into place on Jan. 1.

Just a few months later, plastic bags have largely disappeared from Italy’s stores—and from its streets. Instead, shoppers are bringing their own bags, or buying recyclable corn-based bags for their purchases. “Consumer opinions are changing,” Alessi says. “They’re learning to step lightly on the planet.”

(Related: “Plastic Bag Bans Gaining Momentum”)

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