The Diet-Climate Connection

Center for a Livable Future | June 4, 2021

This is a guest blog co-authored by CWS and the Center for a Livable Future. 

One of the least-discussed aspects of the global climate crisis is how our food system contributes to climate change and environmental damage. Growing, producing and transporting food, particularly animals, contribute nearly 25 percent of human-related greenhouse gas emissions. Globally, raising animals for meat produces more greenhouse gases than the transportation sector—about 14.5 percent more. Additionally, over 30 percent of available land on earth is used for raising animals and growing their feed (70 percent of actual farmland), making the industry the biggest driver of global land degradation, loss of biodiversity, and deforestation of important carbon-sequestering rainforests.

This is not to say that other industries/sectors are not important. Fossil fuels—gas, oil and coal—through their extraction and use, are responsible for 75% of global greenhouse gases which cause global warming. No long-term solution to the global climate emergency can be achieved until we cease our dependency on them. Industry and governments are responsible for ensuring that this happens on the scale and at the speed required, but individuals, families and communities have a role to play in ensuring this transition happens.

This shift is especially needed in high income countries, such as the United States. America is one of the top meat consuming countries in the world, consuming nearly three times more per person than the global average and six times more than that in sub-Saharan Africa.

In a 2019 study, authors from the Johns Hopkins Center for a Livable Future modeled the greenhouse gas and freshwater footprints of increasingly plant-forward diets specific to 140 different countries. They included not only high-income countries, where overnutrition is prevalent, but also in low- and middle-income countries, many of which have widespread undernutrition. For this reason, the study modeled healthy diets that were nutritionally adequate as well as ecologically sound. This meant adjusting caloric and protein intake of baseline diets to levels recommended by the World Health Organization and the United Nations Food and Agriculture Organization—ensuring the diets had recommended amounts of vegetables and fruits and a limit on sugars. In some countries, especially low- and middle -income countries, the adjustments required adding more calories and protein, and in other countries, especially in high-income countries, reductions were needed. A second study in 2020 additionally measured the footprints of the EAT-Lancet planetary health diet, which is rich in plant-based foods such as whole grains, legumes, vegetables, fruit and nuts and very low in meat and other animal products.

The results varied a great deal by country due to differences in their baseline consumption patterns, nutritional adjustments, food production methods and the GHG and water-intensities of foods by country of origin. In many low -income countries, the GHG and water footprints of a healthy, adequate diet actually increased due to the addition of protein from both animal and plant sources, as well as an increase in overall calories. In wealthier countries, the plant forward diets decreased GHG and water footprints significantly, due to the reduction in animal foods—primarily beef and dairy—and lower overall calories.

The studies demonstrated the shift the United States and other high-income countries have to make in what and how much they eat for the benefit of the world. It is incumbent upon those of us living in high income countries to reduce our climate and freshwater impacts so that low- and middle-income countries can achieve adequate nutrition without adding to the overall climate burden.


But how do we do this in such a way that makes a difference? One answer is by implementing a strategy such as Meatless Monday to make positive changes for health while also adopting climate-friendly eating behaviors. The initiative began as a public health campaign in 2003 to address the overconsumption of meat and promote the importance of small, sustainable changes with a simple message, “one day a week, cut out meat!” Since its inception, the campaign has grown into a global movement and is sparking civic engagement and participation by restaurants, hospitals, schools and institutions in more than 40 countries—as well as by individuals who want to make a difference. Meatless Monday is committed to the reduction of meat consumption by 15 percent with the aim of improving both individual health and the health of our planet.

On average, following a healthy meatless day in a wealthy country can reduce an individual’s annual greenhouse gas emissions by an estimated 7 percent. This is equivalent to the climate benefit of burning 335 fewer pounds of coal or using 34 fewer gallons of gasoline a year. In terms of water, it could save the equivalent of a 38-hour shower! And the more people do it, the more the impact grows: If just 30 percent of Americans opted to go meatless just one day a week, it would result in a 2 percent reduction in food-related greenhouse gases – the same as taking nearly 3 million cars off the road. Imagine the positive impacts on communities around the world if we just took this simple step right here at home!

This small lifestyle change, when gathered collectively, can have a big impact toward sustainability. In 2010, the FAO and Biodiversity International defined a sustainable diet as that with a low environmental impact which contributes to food and nutrition security and to healthy life for present and future generations.

Along with Meatless Mondays, here are a few additional ideas you can use to become a more responsible global citizen and ensure a healthy planet for generations to come:

  1. Eat less meat, especially beef. Take one day a week to go without meat and when you do eat it, have smaller portions. Move meat from the center of the plate focusing on plant-based proteins instead, such as beans, tofu, seeds and nuts.
  2. Eat more foods that are good for the soil and not overly water intensive, such as beans, peanuts and root vegetables.
  3. Eat more variety – especially vegetables. Rather than relying on the top 6 vegetables that we eat (potato, tomato, lettuce, onion, carrots and corn), introduce different vegetables throughout the week.
  4. Eat less overall. People who eat fewer calories also have healthier bodies and brains, and live longer.
  5. Choose responsibly grown and raised foods. Look for labels like “Raised without antibiotics,” (meat), “Certified humanely raised,” “Organic” and “Free range.”
  6. Go to the source. When possible, eat foods that you prepare from their natural state. Avoid highly processed foods that used more water, transportation and are produced with added sugar, refined grains and unhealthy fats.
  7. Waste less food. Choose and use responsibly. Buy less, plan well and eat what you have.
  8. Let your fork guide your vote. Support policies and leaders that back sustainable agriculture and dietary guidelines.
  9. Purchase sustainable seafood using Monterey Bay Aquarium’s rating system for your local area.
  10. Enjoy good food. Be thankful for the variety and availability of food we have right here. Savor the flavors of fresh foods, herbs and spices knowing that making responsible choices is good for the planet and also good for you!

The Johns Hopkins Center for a Livable Future provides technical assistance and serves as a science advisor to the Meatless Monday campaign. The Center harnesses expertise from throughout JHU to conduct activities that contribute to the scientific foundation of the campaign. This includes a range of work that builds upon the Center’s comparative strengths as an interdisciplinary academic center within a school of public health, and includes: research projects, literature reviews, communication and science translation activities, educational programming, as well as outreach activities that engage selected public health and nutrition science communities.