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Sustainability, Energy and Environment Community

University of Colorado Boulder


eat mostly plants, waste less

Enjoying food that’s better for you and the planet is one of the most powerful actions an individual can take to slow climate change.



  • Eat mostly plants

    Cut out beef

    Beef (along with lamb) has one of the highest greenhouse gas impacts of all meats (source). If we all substituted beans for beef, and took no other action, the United States could meet 1/2 to 3/4 of its 2020 greenhouse gases target. At the same time, this shift would free up significant US cropland. (source). Pretty incredible!

    Yep, beef has a disproportional impact (source) [carbon percentages & terminology]. Moreover, all meat products have larger carbon footprints per calorie than grain or vegetable products. This difference is due to the inefficient transformation of plant energy to animal energy (Weber and Matthews, 2008).

    Try Meatless Mondays

    Eating less meat does more to save carbon than any other food habit, including buying local (New York Times 2015 article). A typical family of four that decides to cut their meat intake in half could avoid roughly three tons (6,000 pounds) of emissions annually (UCS, EWG).

    Help serve lower-carbon meals

    Ask your workplace, service club, or community of faith to serve lower-carbon meals in its café or during catered events. Suggest chicken instead of beef, or tastier vegetarian dishes.

  • Waste less

    Work toward a waste-free kitchen

    More than a third of food in America is thrown out instead of eaten (PLOS). Much of it doesn't even make it to the store shelves because it has blemishes. Not only does this waste all the resources and carbon that went into the food’s production and distribution, it fills landfills and the rotting process releases methane, a powerful greenhouse gas.

    The overall greenhouse gas emissions of food waste are enormous. In just the U.S., waste equals a year’s worth of greenhouse gas emissions from 37 million cars (NRDC Report PDF file).

    You’ll be on your way to a waste-free kitchen if you

    • Plan in advance.
    • Shop with a list.
    • Avoid impulse buys.

    Freezing food before it spoils can capture what you don’t use right away.

    Save your food!

    Learn about food waste and how to reduce it (1 min).
    From the Save your Food page for the City of Fort Collins.

  • Go local

    Support your local farmer

    Look for farmers’ markets and grocery stores that stock local produce. Or take a share in a community-supported agriculture (CSA) program, where you buy a season’s produce directly from a local farm.

    Buying local food not only reduces emissions from transporting food around the world, but supports a healthy food system and economy in your area. It usually tastes better too.

    Here in Boulder we have a number of local food efforts and organizations.

    Team up with fellow gardeners

    Join a community garden or a garden at your child’s school.

    Promote food justice

    Food deserts are places without grocery stores where people have to rely on quickie marts selling heavily processed food. They are located primarily in communities of color. Use crowdfunding sites like Barnraiser and ioby to support neighborhood projects to grow community gardens and healthful plant-based diets. For example, see a community garden proposal.

    What's your MPH
    miles per hamburger?

    Did you know that consuming a quarter pound burger produces as much greenhouse gases as driving a typical new passenger car about 8 miles?

    Here’s how: Producing a quarter pound of beef results in about 6.6 lbs. of CO2 equivalent (see Univ. of Michigan's CSS carbon footprint factsheet), the average new car gets about 28.6 MPG, and a gallon of gasoline produces 24.1 lbs. of CO2. So it follows that eating a quarter pound burger is the equivalent of driving about 8 miles.

    Of course, your mileage may vary. Oh, and that’s assuming you don’t supersize it.

  • Learn more

    Food is a big source of CO2

    The global food system accounts for 19% - 29% of all greenhouse gas emissions when all factors related to agriculture are considered, such as fertilizer manufacture, food transportation, and agricultural deforestation (source).

    Footprint of food per American

    U.S. food production and consumption contribute about 5,000 pounds of CO2 annually for every American. That's enough gas in 12 months to fill the Washington Monument... twice!. And it adds up to about 14% of U.S. CO2 emissions. (Calculation details).

    Note that the ~14% U.S. value is not directly comparable to the 19% - 29% global value noted above. The global value includes emissions impacts from deforestation and land use changes [Carbon percentages & terminology]. Moreover, the U.S. has a higher percentage of emissions from transportation and other sectors overall, thereby reducing the fraction of emissions from food. A key point to remember is that the pounds of CO2 emitted per capita in the U.S for food is quite high.

    A typical American diet (lots of meat and processed foods) not only puts a lot of carbon dioxide and methane into the atmosphere, but comes with sides of soil degradation and water pollution (Cornell University, EPA, and BioScience journal). It’s not great for your health, either. Furthermore, Americans consuming the most beef have an disproportional impact. These 20% of Americans are responsible for almost half of the U.S. food-related carbon emissions (University of Michigan News).

    Find your carbon footprint

    The above graph shows emissions for the average American. But your personal graph of emissions might be quite different. You can estimate your overall carbon footprint, including food, using one of the many carbon footprint calculators online. Most of them will also give you hints on how to reduce your emissions. We like the Berkeley CoolClimate calculator. Different calculators use differing categories and assumptions, so your numbers may not seem to fit with the above graph [Carbon percentages & terminology]. That's OK. What's more important is that your calculator can still help you reduce emissions.

    More veggies

    Want to try a more plant-based diet, but kale and tofu don’t appeal? Try Mark Bittman’s outstanding How to Cook Everything Vegetarian for simple but delicious recipes you can make in a hurry. Want to make more of a splash? Any cookbook by Yotam Ottolenghi is a worthwhile exploration.

    More thoughts

My food footprint

Portrait of Simon Pendleton

Simon Pendleton

Graduate Student

As a graduate student and an avid cyclist, food is central to my daily routine. However, as a researcher of past and present climate, the impacts of my food choices have become strikingly clear in recent years. Understanding the carbon footprint of different aspects of the food industry (NRDC - PDF file) helps me to make choices to reduce my own individual impact on climate change.

First and foremost: less meat, more plants! I am by no means a vegetarian, but the carbon impact of red meat, for example, far outweighs any desire I may have for a steak (not to mention other environmental impacts of meat production). If I do purchase meat, chicken is my go to, which has a significantly lower carbon footprint per serving (though still higher than other, plant-based sources of protein). Other positive outcomes of eating less meat include lower risk of coronary disease and colorectal cancer and a lower grocery bill!

Aside from occasional meat, >90% of my diet is comprised of plant-based products. Although the carbon impact of vegetables is significantly lower than for meat produced in America, buying more vegetables is just the start. I also try to buy locally sourced produce in order to combat the carbon impact of transporting vegetables from farther away (do you know where your avocados you put on toast come from?). Lastly, when making purchases in the grocery store I try to buy as much as I can in bulk to save on packaging, or buy products with packaging that I can recycle, reuse, or compost.

While the choices we make in the grocery store are important, what we do with food products after we are done with them (leftovers, scraps etc.) is equally important. Greater than 50% of typical municipal garbage is actually compostable (ISLR - PDF file), and all that organic material ends up in landfills where it decomposes and produces methane. However, properly managed composting of all this organic material can reduce greenhouse gas emissions, and provide a whole new industry with significant benefits for the climate and the environment.

Using a climate-aware perspective when making our food choices is not only healthier for us, easier on our wallets, but also has a large impact on the carbon impact of our food and a cascade of other environmental benefits.

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