Chewing gum: environmentally friendly or not?

Illuminating answers to environmental questions.
April 19 2011 7:05 AM

How Green Is My Wintergreen?

Assessing the environmental impact of chewing gum.

Gum. Click image to expand.
The not-so-eco-friendliness of chewing gum

Gum is a blight on civilized society. It's always hiding on the underside of tables, or flattened on the pavement, or sticking to my shoes. Is it bad for the environment, too?

Unfortunately, there's not a lot of environmental data on the chewing-gum industry. But given how useless gum is, at least for most people, the Lantern isn't prepared to cut Big Chew much slack. Unlike food, gum provides no sustenance. Unlike geothermal power, it does no work. Unlike books and computers, gum conveys no knowledge. Sure, the sugarfree sort can help prevent tooth decay to some degree. But, hey ... brush your teeth, man.

And yet, gum-chewing has a long history, going back to the ancient Greeks, who chewed a gumlike product derived from the resin of the mastic tree. (The tree's name shares a linguistic root with the verb "to masticate.") Indigenous North Americans and early European settlers got their chomp on with spruce sap; the first commercially sold gum in the United States followed the same recipe. In 1850, manufacturers swapped out tree sap for paraffin wax. The resulting gum was more stable and cheaper to make, but a lame product. If you've ever tried to chew those silly wax lips, you know why. Paraffin wax is stiff and only softens after several minutes of jaw-busting labor.

Twenty years later, in 1869, a Mexican exile named General Antonio de Santa Anna and American photographer Thomas Adams introduced chicle, a resin, from the sapodilla tree to the American palate. They had been trying to vulcanize the resin into rubber for boots and tires, and failed. As a last attempt to salvage their stash of chicle, Adams and the general made the sap into chewing gum, which had a subtle caramel flavor. Sweeter than spruce and much more pliable than paraffin wax, Adams' chicle quickly caught on nationwide. Within a few years, he was mass-producing several different flavors.

Decades after chewing gum became an American obsession, most manufacturers ditched chicle, replacing the natural resin with a synthetic polymer known as polyisobutene. Today, Goodyear—the same company that makes your car's tires—manufactures the base (PDF) for many major gum brands. (Chicle isn't entirely lost to history; in fact, it's making a comeback as an eco-friendly alternative to modern gum.)

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While the new base produces a supremely soft and chewable gum, it's not biodegradable. In fact, as your parents or teachers might have reminded you, it passes through your incredibly acidic digestive tract largely unaltered.

There's probably not enough gum in the world to create a major environmental issue, but the volume of waste is not entirely insignificant. Worldwide, humans chew about 560,000 tons of gum each year. To put that into perspective, Americans threw away 30 million tons of plastic in 2009, about 28 million tons of which wound up in landfills. If you want to make a rubber-to-rubber comparison, American toss out 290 million car tires every year, weighing in at over 3 million tons. Recycling is common, though: Only one-tenth of those tires are buried in landfills each year.

A few entrepreneurial greenies have developed technology to recycle chewed gum, which they can turn into rubber containers or children's toys. But that means chewers would have to throw their used gum into specially designated waste containers, rather than into ordinary trash bins.

Convincing people to jettison their gum into dedicated bins might be asking a lot, considering how many of us decline even to use regular trash cans. A sickening amount of chewed gum ends up on the ground and cleaning it up takes a staggering amount of resources. Consider London, which has crusaded against street-stuck gum in advance of the 2012 Olympics. The city says it spent three months steam-cleaning 300,000 pieces of gum off of less than two miles of street. A piece of gum costs Londoners just a nickel at the candy shop. It cost the city between 16 cents and three dollars to remove each wad from the pavement.

It's difficult to quantify the cleanup effort's environmental impact; the city hasn't said how much steam it used, or what sort of noxious chemicals might have seeped into the groundwater. (British chemical engineers are working to develop eco-friendlier steam-cleaning methods.) Even so, the tens of millions dollars spent on the effort would have been better spent on recycling or promoting composting.

None of the major gum manufacturers have released life-cycle analyses on their products. A group of Dartmouth students did, however, analyze (PDF) several types of gum wrappers. It turns out that Bubble Tape-style products—where a single plastic shell, instead of many individual wrappers, holds the gum—were responsible for the least amount of greenhouse-gas emissions.

Brian Palmer writes about science, medicine, and the environment for Slate and the Natural Resources Defense Council. Email him at explainerbrian@gmail.com. Follow him on Twitter.

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