The Impact of Your Grocery Store Choices: Nitty-gritty

July/August 2009

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Q: Can the choices you make at the grocery store truly impact the environment?

Asked by Monica Jain, ’85, Carmel, Calif.

A casual stroll down a grocery store aisle shows that it’s not easy to determine the environmental impacts of any given food item. The food industry is a major player in such environmental issues as deforestation, land-use change, water wastage and excess fertilizer run-off. And that’s to say nothing of the greenhouse gas emissions associated with of agriculture, shipping, and food processing and storage. Carbon emissions are a good proxy for many of these environmental issues, so let’s focus specifically on the climate impact of food here.

An increasingly popular method of judging an item’s eco-friendliness is to perform a life-cycle analysis, also known as a cradle-to-grave analysis. The idea is to examine the carbon emissions or other environmental impact at every step of creating a particular food item, from planting the first seed right up until the final product lands in your shopping cart—or better yet, until the empty container, if there is one, is recycled into a new product.

For example, take a bottle of ketchup. First, you’ve got the raw production of all the ingredients, primarily sugar and tomatoes. Into this production go lots of pesticides, fertilizers and water. Plenty of fossil fuel energy is used to plant, spray and harvest the crops. The harvested raw products are shipped—more carbon emissions—to factories where they are converted to secondary products like tomato paste and sugar solution; the secondary products meet up in the ketchup factory; and the final product is packed in bottles, which had a whole production process of their own. The finished product is shipped to stores, and then finally makes it into your household; when the ketchup container is empty it heads on over to the landfill or, one hopes, to the recycling center.

Sound like a lot of steps to account for? This is just the simplified version! As you can imagine, doing this for every food item on the market is a lot of work, but it also helps consumers make informed choices. Several certification organizations have formed to perform this sort of analysis on food and other products, and “carbon footprint” or “environmental impact” labels might one day be as common on foods as the nutrition label is now.

Climate impact assessment and certification is just beginning to take off, and maybe before long everything we buy at the store will have a label declaring its carbon footprint. But in the meantime, here are a few things to think about, to help you do a rough life-cycle analysis of your own while in the store:

The closer, the better. The farther away a product was made, the more carbon was used to ship it to you. In the United States, produce is shipped an average of 1,500 miles from where it was produced to its final destination, burning fossil fuels all the way. By buying locally, you’re not only likely getting food with a smaller carbon footprint, you are also probably getting fresher food that wasn’t harvested while vastly underripe. Try to purchase fruits and vegetables that are in season; they’re the ones that haven’t been raised in South America or in energy-guzzling greenhouses.

intensity graph
Carbon emissions of different food groups based on household, price, energy content, and mass. (Source: “Food-Miles and the Relative Climate Impacts of Food Choices in the United States,” Environmental Science & Technology)

Less processing means less carbon. Many environmentalists contend that the greatest carbon emissions in a food product come from its production, not its transportation. For example, frozen carrots have a carbon footprint three times greater than fresh carrots due to the additional processing that goes into preparing and freezing them. Cooking your own lasagna from fresh ingredients is tastier, greener and more rewarding than getting any premade, microwavable kind, even if it’s organic.

Packaging=waste. When we purchase food, we’re often thinking of the quality of the food itself, not the packaging. But packaging involves lots of refining of plastics and other material, which usually end up in the landfill. It’s also a huge source of carbon emissions. As one simple example, the creation of plastic yogurt containers uses twice as much energy as any other portion of the production process—including making the yogurt. When possible, buy products in bulk so that packaging is minimized, or at least go for products with recyclable or reusable packaging. Packaging also comes into play in the checkout line: paper or plastic? You might be surprised to learn that plastic bags have lower associated carbon emissions, plus they’re reusable as trash bags. Of course, the best option is to bring your own bag.

Eat less red meat. The livestock industry alone accounts for 18 percent of global greenhouse gas emissions. Purchasing more sustainable meat products can help cut back on local pollution, and just switching to a different type of meat can impact your climate footprint: the carbon emissions of beef are eight times that of chicken.

Know the labels. The popularity of eco-friendly foods has led to plenty of misleading claims by the food industry. Before you buy any product with a green claim, investigate what the label really indicates. For example, all “organic” certifying agencies must follow USDA guidelines, but the “free range” label is only regulated on poultry, and the “freedom” of the “range” might be a lot less than you would think. When evaluating which products to buy, look for specific logos of certifying agencies, such as “Certified Humane Raised and Handled,” not just general claims such as “cruelty-free.” Importantly, going organic makes a bigger difference for some foods than others—look especially for produce usually grown with heavy pesticide applications.

Visit the farmer’s market. If you don’t already shop at your local farmer’s market, you should definitely give it a try. Warmer climes may have an advantage, but farmer’s markets can be found practically everywhere. Food purchased at these locations satisfies nearly every one of the recommendations listed above: It’s local, fresh, seasonal, unpackaged and often organic. Farmer’s markets also avoid other food-related carbon sources such as super-bright supermarket lights and open refrigeration, which, according to Climate Conservancy’s analysis, can account for up to 30 percent of the carbon emissions for products like beer. And because farmer’s markets eliminate some resource use and retail markups, the products are often cheaper.

So, how much of a difference can each of these changes make? A recent report quantified the carbon savings in terms of something we know and love: mileage. Switching from the average American diet to one of all-local ingredients is equivalent to driving 1,000 fewer miles annually. Eliminating red meat can lead to even greater carbon savings: 750 miles if you simply switch to chicken one day per week, and 1,000 miles if you switch from red meat to a vegetarian meal just once a week. So what are you waiting for? It’s time to cook a tasty meal and feel good about all the energy you’re saving at the same time—the way I see it, that offsets my dessert, right?

For more information on your supermarket choices:

1. “Livestock's Long Shadow: Environmental Issues and Options,” Food and Agricultural Organization of the United Nations

2. Foster, C., Green, K., Bleda, M., Dewick, P., Evans, B., Flynn A., Mylan, J. (2006). Environmental Impacts of Food Production and Consumption: A report to the Department for Environment, Food and Rural Affairs. Manchester Business School. Defra, London.

Heather Benz plans to receive her bachelor’s degree in earth systems in 2010.

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