Take the Bite Out of Global Warming
by Eugene Cordero, Ph.D. • California

When attempting to reduce their carbon footprint, many people are now discovering that flipping their dinner plate around is the best way to go green.

Recent research on the causes of global warming reveals that while transportation and home energy use are big contributors, the daily food choices we make also matter. In fact, when researchers calculated the energy required to grow, produce, and transport food for every American, the results showed that eating an average diet generates about the same carbon emissions as driving a mid-sized car over a year. Especially in these tough economic times when buying a new hybrid car may be prohibitive, these facts have lead some to reconsider how they go about saving the planet.

A warmer planet is not something new to our climate system, as there have been warmer and cooler periods in our recent past (last 100,000 years). What is new and potentially troubling is the rate of warming and the understanding that humans are ultimately responsible for most of the observed warming of the last half century.

The solutions to global warming are diverse. There is not one simple cure, but instead a variety of different strategies are required that all work to reduce energy use and emissions. One piece is technology, and the good news is that we already have some of the required technology to make these changes. Wind turbines, solar cells, and lower-energy-appliances are becoming more efficient and affordable. Another piece, and it’s quite a large one, is our agricultural system, which contributes at least 25% of the world’s greenhouse gas emissions. This realization came into focus when the United Nations Food and Agricultural Organization reported in 2006 that the farming of animals for food was responsible for more greenhouse gas emissions than our transportation sector. Solutions to reducing our food-related emissions are readily available, and they start at our dinner plate.

For carbon emissions, not all foods are created equal. To calculate the carbon footprint of a food item, the total amount of energy required to grow the food is estimated by considering all aspects of growing, including farm machinery, irrigation, production, and application of fertilizers and pesticides. Add to that any processing of the food, and then finally the transportation from farm or factory to plate, and you get the carbon footprint of your food or the “carbon foodprint”. Published estimates show that vegetables and grains such as potatoes, corn, and rice have relatively low carbon foodprints, while animal products, especially red meat, have large carbon foodprints. And although local foods generally have much lower foodprints than imported foods, the energy required for growing is normally a larger contributor than the energy required for transporting the food.

So, this is where the flipping of our dinner plate becomes important. Take a look at the standard American dinner and you’ll typically see a piece of beef, pork, or chicken surrounded by a sprinkling of grains and vegetables. Flip this meal around and the grains and vegetables become the main focus, with animal products as a side dish or adding flavor. What this does is not only reduce the carbon footprint of a meal, but it’s also typically less expensive to make and provides the understood health benefits of a diet rich in grains and vegetables.

As an example of this flipping, consider the stir-fry recipe given below. The recipe offers three ways to make a stir-fry, using either beef, chicken, or all vegetables. Although it seems a casual decision, in terms of associated carbon emissions, there is quite a difference. The base ingredients for the recipe include making a sauce from stock, wine, and lemon that produces about 3 lbs of CO2. Add to that more
vegetables as in recipe 1 and you get a total of 6 lbs of CO2. If you choose the chicken stir-fry in recipe 2, the total goes up to 12 lbs of CO2, but if you choose the beef recipe, the total is more than 34 lbs of CO2! In this case, even by switching to chicken from beef can save more than 20 lbs of CO2, the same amount of emissions that are generated by driving a car 25 miles. We have come to the realization that our food choices can have a more profound impact on global warming than the car we drive.

Basic Stir-Fry—3 Ways:
This is a basic but tasty stir-fry recipe. Serves 4
Stir-fry Sauce
1 cup vegetable stock
2 tablespoons soy sauce
1 tablespoon dry white wine
1 tablespoon freshly squeezed
lemon juice
2 tablespoons cornstarch

1 pound of veggies
(peppers, broccoli, carrots)
Recipe 1: Veggie Stir-fry
1 pound of additional veggies
(e.g. mushrooms, eggplant, etc.)
Recipe 2: Chicken Stir Fry
1 pound of chicken pieces (1-inch)
Recipe 3: Beef Stir-Fry
1 pound of beef pieces (1-inch)
Combine ingredients for sauce and set aside. If using meat, preheat wok or sauté pan on medium-high heat. Add 1 tablespoon oil and chicken or beef. Stir-fry until cooked through, about 5 minutes. Remove from pan. Add another tablespoon oil and sliced vegetables and stir-fry, about 5
minutes. While cooking, add 1 tablespoon cold water as needed to “force-steam” vegetables. When vegetables are crisp tender, add stir-fried chicken or beef. Whisk Stir-fry Sauce, making sure cornstarch is mixed in. Add sauce to wok. Cook until thickened.

Based on the book, Cool Cuisine: Taking the Bite out of Global Warming (Gibbs Smith Publisher ©2008) which explores the connections between climate change and our food system. The book is part cookbook, part science book, and is written jointly by a chef, Laura Stec and climate scientist, Eugene Cordero.

Dr. Eugene Cordero is an Associate Professor in the Department of Meteorology at San José State University (SJSU) in California. His research interests are focused on understanding the processes responsible for long-term changes in climate and in improving methods of education that engage and ultimately stimulate social change.