How diet and agricultural practices contribute to climate change


A plant-based meal that's healthy for you and the planet.

A plant-based meal that’s healthy for you and the planet.

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Editor’s Note: This is the fourth in a series of columns by Joana Tavares, Mass Media Fellow of the Tribune’s American Association for the Advancement of Science, to answer reader questions about climate change. Tavares has a PhD in Earth Sciences from UC Irvine.

“I’d love to see you share how the diet we consume contributes to climate change based on agricultural food production practices.” Wendy, San Luis Obispo

Dear Wendy,

Diets are a big deal, aren’t they? I feel like I’ve tried them all: low-fat, high-fat, low-carb, keto, pescatarian, vegetarian, you name it. I know I’m not alone on this journey of figuring out how to “eat right,” whatever that means for each person.

Choosing what to eat is such a big part of our lives, yet most of us know so little about where our food comes from, how it’s made, or how it affects the rest of the world. This separation is a real problem for our health and for the health of the planet.

Most modern farms don’t look like Old MacDonald’s

There is indisputable evidence that industrial agriculture and factory farming destroy natural ecosystems, pollute water supplies, deplete soils around the world and produce large amounts of greenhouse gases that warm the planet and cause climate change. Globally, food production accounts for up to 40% of all emissions from human activities.

Over the past century, unsustainable practices such as tillage, monoculture and the indiscriminate use of pesticides and fertilizers have become commonplace in the business of producing ever-increasing amounts of biomass relatively cheap but nutritionally questionable food.

The solutions to most of these problems are grouped under the umbrella term “regenerative agriculture”. Scientists are working to determine how much these practices can do in terms of reducing greenhouse gas emissions, and So far the results are encouraging. Soil remediation not only appears to reduce emissions from agriculture, it could also serve to remove and store carbon from the atmospherewhere it cannot warm the planet.

Community Gardens_Lede1
The community gardens of the city of San Luis Obispo produce an abundance of fresh fruits and vegetables. In the foreground on July 7, 2022 is a planter with a healthy zucchini plant. Laura Dickinson [email protected]

If you want to know more, I recommend watching the documentary “Kiss the Floor” and visit the websites of various local organizations promoting sustainable agriculture.

  • That California Climate & Agriculture Network is a coalition of farming organizations committed to state and federal action to ensure the resilience of local farms and ranches in the face of climate change.
  • That Cachuma Resource Conservation District promotes economically viable and environmentally sustainable farming and livestock operations.
  • FOR LOVE OF THE SOIL is an independent soil science, communication and arts organization co-founded by two soil experts, Yamina Pressler and Karen Vaughan.

Implementing regenerative agriculture on a large scale is a real challenge. Farmers, ranchers and consumers need to be educated, and the lobbying by powerful corporations who want to maintain the status quo stopped. But in general, regenerative farming is an easy sell idea.

The conversation usually gets awkward when we bring up the one industry responsible for the largest share of greenhouse gas emissions from food production: meat and dairy.

Shame and the meat-climate paradox

There is no definitive figure for the total amount of greenhouse gases produced by the meat and dairy industries. In 2013, the United Nations’ Food and Agriculture Organization calculated it was 14.5% of global emissions, and experts say that figure is an underestimate. The math is complex because business is complex.

Carbon dioxide is released in all operations, from deforestation and clearing for pasture and fodder crops to the refrigeration needed for the storage and transport of animal products. Then there’s the infamous methane from flatulence and belching from ruminants, mainly cows and sheep, and let’s not forget manure, which releases even more methane and nitrous oxide as it decomposes.

Animal husbandry, as currently practiced in most parts of the world, is not healthy.

scientists appreciate that if you only consider greenhouse gas emissions from diet, meat eaters are responsible for almost twice as many emissions as vegetarians and about two and a half times as many as vegans.

Given all this information, what I’m about to say next might seem paradoxical, but here it is: I don’t think we should be telling people to stop eating meat and dairy.

Although veganism is growing in popularity, not everyone is willing or able to make the full plant-based diet. People have all sorts of cultural, ideological, and health reasons for continuing to eat meat, and the push for total veganism as an “obligatory sacrifice” will alienate many people we desperately need to get involved in the climate movement.

Focusing the discussion of climate action on how people are fed can also divert attention from more pressing societal changes like phasing out fossil fuels. Climate shame – including food shaming – is a strategy employed by fossil fuel advocacy groups to split the climate movement and weaken its bargaining power.

Switching to a plant-based diet is a good start, but to solve the climate crisis we need to change systems. We must fight together for immediate government action that reduces emissions from all sectors: power and heat generation, industry, transport, buildings and yes, agriculture and land use too.

A good compromise would be to ask people to reduce their consumption of animal products and to offer practical alternatives and a cultural context that facilitate their choice. initiatives like Meatless Monday, Veganuary and VegFests are creative ways to build community around cause because they turn “personal sacrifice” into fun social experiences.

Why not invite friends and family to try vegan food this weekend? Here are some restaurants that serve plant-based meals:

Community Gardens_Lede2
The community gardens of the city of San Luis Obispo produce an abundance of fresh fruits and vegetables. Fresh tomatoes ripen on the vine on July 7, 2022. Laura Dickinson [email protected]

Low-hanging fruits

Another issue is how wasteful food production currently is in all its aspects.

About a third of the food produced on the planet is wasted. Most food (70-80%) is lost before it reaches consumers, but food wastage from households can be significant in developed countries.

Food waste is to blame for 8-10% of global greenhouse gas emissions. This estimate only takes into account the emissions used in the production of the food. The methane released as this food rots in landfills is a double whammy.

To combat food waste at home, we should better plan meals and grocery shopping, and then separate food waste and organic materials for composting. California recently passed legislation Food waste must be disposed of in the green bin rather the garbage.

Residents of SLO County can also rely on the Anaerobic digester from Hitachi-Zosen, a first of its kind in the United States. This technology makes it possible to convert all types of organic waste, including meat, dairy and fat, into all-natural fertilizer and biogas. The biogas is then used as a renewable fuel to generate electricity, which is fed into the San Luis Obispo area power grid. The plant produces enough energy to power around 600 homes and serves as a good example of how systems can be improved.

As I have already admitted, I have personally struggled with my diet for many years. Growing up in the Brazilian countryside hunting, fishing and raising animals, I would be lying if I told you that it was easy for me to switch to a plant-based diet.

These days I eat very little animal products, I don’t eat beef and I try to buy locally sourced food. It took a re-education and re-evaluation of my mental models to let go of some beliefs about nutrition that I now realize were flawed. And I’m still a fan of cheese.

The way I see it, there are many paths to sustainable living and I hope we can all continue to learn and work together to implement solutions to this global existential crisis.

The author would like to thank Wendy Fertschneider, RD, retired Public Health Dietitian, County of San Luis Obispo, and Erin Pearce, PhD, Cal Poly SLO Professor and Director of the Initiative for climate protection and resiliencefor their contributions to this article.

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Joana Tavares is a Mass Media Fellow from the American Association for the Advancement of Science. She writes about earth, ocean and climate sciences. Joana received her bachelor’s degree in oceanography from the Federal University of Rio Grande in Brazil. She also has a master’s degree in marine science and policy from the University of Delaware and is currently completing a PhD in Earth Sciences from UC Irvine, where she is funded by a Future Investigator in NASA Earth and Space Science and Technology fellowship.


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