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.
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!
See an interactive 2019 article in The New York Times that answers your questions about food and climate change. The article includes a discussion and chart showing the average greenhouse impact of many kinds of protein sources. It refers to a scientific paper by Poore and Nemecek (2019), who looked at the environmental impacts of ∼38,000 farms producing 40 different agricultural goods around the world.
Yep, beef has a disproportional impact (source) [ ]. 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).
Our column chart is based on a similar chart created by the Univ. of Michigan Center for Sustainable Systems (CSS). They used U.S. data from Heller and Keoleian (2014), which in turn looked at multiple studies of carbon emissions for each food type. For example, an assessment of 18 separate studies led to their calculation of 6.61 pounds of C02 emissions for a 4 oz. serving of beef. These results are supported by studies of global data, such as Poore and Nemecek (2019).
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).
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.
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
Freezing food before it spoils can capture what you don’t use right away.
Learn about food waste and how to reduce it (1 min).
From the Save your Food page for the City of Fort Collins.
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 the SHED, which educates about and advocates for the Boulder County foodshed. Look in your area for a similar organization.
Join a community garden or a garden at your child’s school.
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.
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).
Percentages listed in one place on this website can seem to contradict numbers listed elsewhere. But there isn't any contradiction and the percentages aren't wrong. Instead, the numbers come from studies that aren't directly comparable because of different categories, different assumptions etc. For example, the pie chart on our Science page is based on emissions from five U.S. economic categories: electricity, transportation, industry, commercial+residential, and agriculture (EPA calcuation). Those percentages cannot be directly compared to the ones we show on the home page for a similar, but different set of U.S. categories: energy, transport, products, and food (UCS calculation). In other cases, we discuss global average percentages, which can vary substantially from corresponding U.S. values.
Greenhouse gases come in many forms such as carbon dioxide (CO2), methane, and nitrous oxide. CO2 is the largest overall contributor to climate change. But less common gasses like methane have a much more powerful effect per pound of gas than CO2. In order to have comparable numbers, we convert all the greenhouse gases into a “CO2 equivalent” for this website. For example, when we state the CO2 emissions for beef, the number includes the methane produced by the cow converted into an equivalent amount of CO2.
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).
The text above and the graph below are based on percentages of carbon emissions across four source categories from a Union of Concerned Scientists 2012 report and a table in that report . Those percentages are multiplied by the ~36,000 pounds of CO2 per person per year (2014) value assembled by the Oak Ridge National Laboratory, and later reorganized and visualized by World Bank.
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 . 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).
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 [ ]. That's OK. What's more important is that your calculator can still help you reduce emissions.
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.
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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