Which Diet Coke Container Is Better for the Environment?

Skipping just one day trip to Mount St. Helens will do more to reduce global warming than giving up Diet Coke for a year.

Though many chastise me for the habit, I like my Diet Coke. Since I’m going to drink it anyway, is it better for the environment to drink 2-liter bottles, 12-ounce cans, or 12-ounce glass bottles? —Thirsty in Beaverton

Cans. Thanks, everybody; see you next…what? Paid by the word, you say? Ah. Well, actually, this is a much more subtle topic than it might appear at first blush. Let us explore, together, at our leisure.

The carbon impact of various types of soda container has been calculated (read: estimated) multiple times. Glass is generally considered the worst offender—due to its weight, it’s more energy intensive to transport than other forms of packaging. Plastic bottles are lighter to transport, but manufacturing them isn’t exactly carbon neutral.

Canned soda—assuming the aluminum cans are recycled—is usually judged the least-worst option in terms of greenhouse-gas emissions. Moreover, as a bonus for you, Thirsty, the GHG impact of sugar and/or high-fructose corn syrup means that the diet version actually represents slightly less carbon (about 85 g) than regular Coke (about 105g).

Of course, Diet Coke lovers’ green bragging rights are somewhat mitigated by the fact that—like Zoloft, amphetamine and psychedelic mushrooms—its sweetener aspartame can pass straight through the body and into the waste stream without being broken down. The consequences of this for our rivers, lakes and oceans are unknown—I’m hoping it’ll just be a lot of happy, slender, spiritually grounded fish with super-clean apartments, but I’m not betting the farm on it.

Still, let’s put those 85 grams in context: If you drink one can of Diet Coke each day for 365 days, and you recycle the cans religiously, you’ll add 68 pounds of CO2 to our beleaguered atmosphere. That sounds bad, but it’s the same amount you’d create by driving an average car 75 miles.

I don’t mean 75 miles a day for 365 days, either; I mean 75 miles, period. Skipping just one day trip to Mount St. Helens will do more to reduce global warming than giving up Diet Coke for a year. That doesn’t mean Diet Coke is great, but Americans generate 19 tons of carbon per capita each year—until we stop nickel-and-diming each other about soda cans and start killing ourselves, we’re just rearranging the deck chairs on the Titanic.

Questions? Send them to dr.know@wweek.com.