Animal agriculture isn't destroying the planet – and a sustainability scientist has the peer-reviewed data to prove it

The claim circulates constantly: if everyone went vegan, we could solve climate change. It feels compelling. The science tells a more complicated story.

Dr. Kim Stackhouse-Lawson is the director of AgNext and a professor of animal science at Colorado State University, where her team brings together producers, industry partners, and researchers to develop real-time sustainability solutions for animal agriculture. Before returning to academia, she was director of sustainability for JBS USA, coordinating the North American sustainability program across beef, pork, poultry, transportation, and branded products.

She joined the Food Bullying Podcast to address the environmental claims made against animal agriculture with the specificity they deserve – and to explain why the conversation about sustainability in food systems is far more complex than any single headline can capture.

What sustainability actually means in animal agriculture

Before addressing the environmental claims, Dr. Stackhouse-Lawson reframes the definition of sustainability itself – and it's a reframe that matters for everyone from dietitians to agribusiness professionals to policymakers.

Sustainability rests on three equally critical pillars: environmental, economic, and social. The environmental pillar dominates consumer conversation, but in practice, all three are interdependent. An environmentally excellent farming practice that isn't economically viable won't survive. An economically profitable operation that damages its community undermines the social fabric that rural food production depends on.

In animal agriculture, the social pillar is often the one producers think about first, because they work with living animals every day. Animal health and well-being are social sustainability issues. So is generational transfer – the ability to hand a working ranch or farm to the next generation. So is the infrastructure that supports rural communities: the schools, broadband access, and local economies that determine whether those families can stay.

A family in southeastern Colorado driving 90 minutes each way to reach a rural school is part of the sustainability equation for the meat in your grocery cart. That connection is almost never made.

How methane from cattle actually works – and why zero isn't the goal

Cattle produce methane as a natural byproduct of digestion. This is not in dispute. What is frequently misrepresented is how much it matters, how it works biologically, and what reducing it would actually mean.

Cattle are ruminants. Their digestive system – specifically the rumen – hosts microbial populations that break down grasses, forages, and other plant material that humans cannot digest. Those microbial populations convert indigestible plant matter into high-quality protein in the form of meat and milk. As a byproduct of that fermentation process, methanogen microbes produce methane. The animal releases it primarily through its mouth – through burping, not from the rear, as is commonly assumed.

From a nutrition perspective, that methane represents a loss of metabolic energy. That's what makes methane reduction research so promising: if scientists can reduce the amount of methane an animal produces, they may also be able to make that animal more efficient at converting feed into meat or milk. Reducing methane could simultaneously lower environmental impact, reduce the amount of feed required, and improve animal performance. All three pillars of sustainability improve together.

The critical distinction for climate conversations: methane from cattle is biogenic methane. It cycles through the atmosphere and breaks down within approximately 12 years as part of the natural carbon cycle. CO2 from fossil fuel combustion persists in the atmosphere for over a thousand years. Treating these two greenhouse gases as equivalent environmental harms – which most food and climate comparisons do – is not supported by the science.

What would actually happen if everyone went vegan?

A 2017 study by White and Hall provides the most rigorous answer available to this question. If the entire U.S. population adopted a vegan diet, the total reduction in greenhouse gas emissions would be 2.6%. Globally, the reduction would be less than half of one percent.

Dr. Stackhouse-Lawson is careful to note this figure comes from a serious, peer-reviewed life cycle assessment – and even it doesn't capture the full complexity of what a total elimination of animal agriculture would mean. Removing animals from the food system isn't just removing meat and dairy from plates. It removes leather, fats used in soaps and personal care products, pet food, and byproducts embedded throughout manufacturing. It removes the upcycling function that keeps enormous volumes of human food waste out of landfills. It removes the land use pattern of grazing, which in well-managed systems sequesters carbon and supports biodiversity.

Landfill methane is, incidentally, one of the three largest sources of methane emissions in the United States – alongside enteric emissions from cattle and emissions from oil and gas. Cattle that eat brewery waste, bakery discards, almond hulls, cotton seed husks, and distillers grains are keeping those materials out of landfills where they would generate their own methane. That's not a marketing claim. It's a life cycle accounting fact.

Cattle as food waste upcyclers: the sustainability story nobody tells