Q: I have an aversion to creating garbage, and as such, I find disposable coffee cups abhorrent. When I mentioned this to a friend once, his retort was, "Think of all the water you waste washing your ceramic mug, and the energy necessary to produce the mug in the first place." What are the real equations at play here? How many times would I have to reuse my mug to make it the ecologically "better" alternative?

Asked by Erik Uzureau, '01, Tuscon, Ariz.

Forget about the mug and focus on the contents

We'll take a closer look at the environmental impact of your drink choice soon, but let's first delve further into reusable cups. They're definitely not all created equal, but it's hard to imagine a reusable option that isn't better than the available disposable options.

While my personal favorite mug is a plastic tumbler, it shares a home in our cupboard with my roommate's stainless steel travel mug and our large collection of ceramic mugs. To compare these four options, I turned to the Life Cycle Assessment (LCA), which assesses the environmental impact of a product from cradle to grave. In the little-known world of reusable cup research, the main life cycle assessment was conducted by M.B. Hocking at the University of Victoria in 1994. It was updated to reflect changes in appliance efficiency in 2006.

What did they find? As mentioned in the Essential Answer, you only need to use your ceramic mug or plastic cup a handful of times to break even with the industry standard cup in terms of environmental impact. These plastic cups contain less plastic than the tumbler I use, but even doubling or tripling the amount doesn't change the fact that the break-even point is manageably low. Keep in mind, however, that this conclusion assumes you are using a dishwasher. Hand washing dishes is not only less fun but uses considerably more water and energy, as SAGE has reported previously.

Although stainless steel was not included in this life cycle assessment, the recent appearance of steel water bottles and travel mugs has hardly gone unnoticed. One environmental advice-giver has estimated that you would need to use a stainless steel mug approximately 170 times before it would break even with a Styrofoam cup. But steel is also hardier than other reusable materials, and another columnist recommends stainless steel over other mugs partially for its look, and partially because it generally has a high recycled content.

Sustainable coffee 101

Are you as shocked as I am about the impact of coffee on our resources? Let's not get so lost in the details of coffee cups that we lose sight of the overall impact of drinking that daily cup (or three) of coffee. Luckily, you have the power to make your coffee-drinking experience a greener one, and it can be as easy as looking for three certification labels that can alert you to a more environmentally and socially responsible way to enjoy a hot brew. They are fair trade, organic and shade grown.

Fair trade coffee is certified by Fairtrade USA to ensure that producers and workers are receiving fair prices for their coffee. It takes into consideration social factors, such as labor conditions and community development initiatives. This annual certification also evaluates environmental practices, focusing on sustainability and banning agrochemicals and genetically modified crops. Look for this label at your local coffee shop or on your bag of coffee.

Organic coffee is certified by the U.S. Department of Agriculture. This certification is primarily focused on the agricultural process and requires that at least 95 percent of the ingredients in coffee are organic. In the sustainable agriculture community, there has been some controversy over this label as it allows certain chemicals to be used and does not address any underlying economic issues.

In terms of overall environmental impact, seeking out shade-grown coffee might be the most important thing you can do. This coffee maintains forest cover over coffee plantations. That can provide habitat for birds—including many migratory species that spend part of their year in North America—which otherwise would be displaced, and also conserves broader biodiversity and prevents erosion. This type of coffee may also be better tasting as the coffee beans ripen more slowly, thus giving the final product a richer flavor. You may have to look a little harder for "shade grown" or "bird friendly" certification, but two organizations, the Smithsonian Migratory Bird Center and the Rainforest Alliance, provide standards and labeling for it. Can't find them in the store? Luckily, the organizations provide guides of stores and online retailers that sell certified products: Rainforest Alliance Marketplace, Bird Friendly Coffee stores and online retailers.

One last option is to give up coffee altogether. "I need my caffeine!" you say. Well, yes. But you might consider a switch to black tea. Perhaps I'm a tad biased, as my caffeine addiction comes in the form of chai tea, but the evidence shows that tea is simply friendlier to the environment than coffee. For example, one cup of Darjeeling tea, whether organic or conventional, is responsible for about half the amount of carbon emissions as an equivalent cup of coffee.

co2 emissions chartThe amount of carbon emissions resulting from the full lifecycle of teas and coffee. Coffee has a significantly higher impact, especially during cultivation. (Graph: Doublet & Jungbluth 2010)

Still can't imagine giving up coffee? Then, ideally, you should hedge your bets and look for triple-certified coffee that meets the requirements of all three label types described above. Triple certification can be hard to come by, however, so my recommendation is to purchase fair trade coffee. This is a holistic and trustworthy certification that not only encourages good labor practices but requires sustainable farming and a fair price.

The future of the disposable cups

Sometimes, no matter how much you try, you'll end up with an unsustainable cup of coffee in a disposable cup. With any luck, though, you don't have to be wracked with guilt, because disposable cups are becoming increasingly friendly to the environment.

Let's consider Stanford: Stanford Dining's Sustainable Foods Coordinator, Matt Rothe, MBA '07, emphasizes that "there is pretty good evidence that reusable is better on all fronts." To emphasize their commitment to this, Stanford Dining offers a 25-cent discount in all of its cafes if you bring a reusable cup for your drink, and gives out free stainless steel water bottles. But behavior change is difficult, so Stanford Dining is trying to green the disposable dining experience, too. In January of 2009, Stanford Dining converted almost all of its cafes to compostable serviceware, including compostable beverage cups with a biodegradable corn plastic liner.

Many national coffee companies are jumping on the sustainability bandwagon. Both Starbucks and Tully's have 10 percent postconsumer recycled content paper cups. Starbucks sponsored a competition called betacup that solicited ideas to eliminate paper cup consumption. The winner was a project called Karma Cup in which every 10th person to bring in a reusable mug received a free drink. Starbucks's CEO Howard Shultz has also pledged to make all of their cups recyclable by 2012. Peet's, a familiar coffee shop in the Stanford area, is committed to sustainably grown coffee and has the first LEED Gold Certified coffee roasting plant in the United States. Nearly all coffee shops also give 10-cent discounts for bringing a reusable cup. Save the planet and your wallet with a reusable cup!

If all else fails, just remember your laptop. Ask for a for-here cup: most coffee shops have them, they're just hidden behind the counter. With many coffee shops now offering free wireless, you can enjoy your coffee, get work done, and feel confident that you are choosing a sustainable option. Speaking of which, all this talk of coffee has got me craving some chai, so I am off to get my fix. If I can just remember where I put that reusable, plastic tumbler. . . .

Bethany Wylie, '10, is a graduate student in earth systems.