Toning down plant vs. animal rhetoric

The benefit for the climate could be in linking systems closer to reduce waste

Animal agriculture is responsible for only about four per cent of U.S. greenhouse gas emissions.
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The true measure of livestock farming and sustainability is found somewhere between the big picture and the devil in the details.

Sara Place, chief sustainability officer, Elanco Animal Health, boiled down the opportunities and challenges mired in societal perceptions, ecological impacts and the economic feasibility around sustainability at the recent Royal Agricultural Winter Fair’s Virtual Experience.

Why it matters: The vociferous debate over the use of animals and their climate impact isn’t as simple as some make it out to be.

“All of these things are issues that are important, but how we value them will vary person by person,” said Place. “That’s one of the key things to understand and respect when we have these conversations about sustainability.”

It isn’t about plants versus animals, she said, but rather linking the two tighter together to minimize loss or turning would-be losses into things of worth, while producing high-quality products for consumers.

“There is no single answer to all of this,” she said. “It’s very complex and it is about a lot of shades of grey. These things are in flux, all the time.”

The best way to measure the impact of livestock feed is through the global feed ration, which takes into consideration all the domesticated farm animals in the world, she said.

It reveals that only 14 per cent of all livestock feed worldwide is in direct competition with human food.

Sources of American greenhouse gas emissions. Animal agriculture is responsible for about four per cent of U.S. greenhouse gas emissions. photo: Courtesy Sara Place

“Meaning they’re taking a mouthful of something that could be eaten by people,” Place said. “So, 86 per cent of what livestock consume, are things that we humans can’t eat, it’s inedible.”

The Food and Agriculture Organization of the United Nations (UN FAO) Global Food Security study found livestock rely predominantly on forages, crop residues and byproducts not edible to humans. The study stated, on average, cattle only need 0.6 kilograms of human-edible feed in their ration to produce one kilogram of human-edible protein in the way of meat and milk, which is of higher nutrient quality.

Ruminants, especially, are upcyclers, with grain-finished beef cattle converting 1.6 pounds of human-edible feed into 13.8 pounds of human-edible product. Dairy cow’s ratios stand at .27 pounds to 1.1 pound of milk. Pigs and chickens rate much lower.

Land use is the flip side of the resource competition coin with some suggesting land used for livestock, whether for grazing or housing could be used more effectively for food production.

The United States Department of Agriculture (USDA) numbers from 1975 to 2017, show a 52 per cent increase in the amount of corn feeding livestock. However the same time frame shows a 26 per cent reduction in production acres and an increase of 104 per cent in corn yields.

This shows the total red meat, poultry and dairy production in pounds also increased 95 per cent over the 42-year span.

“This is an example, we could say, of decoupling total production from the resource inputs that are required,” Place said. “The land area required has shrunk because yields per acre have increased and yet total output has increased. So, productivity is really key and an important part of sustainability.”

Place said soil erosion and how to improve soil health, increase nutrients and lessen topsoil loss are key issues in North American agriculture.

Place said pastured rangelands hosting ruminant livestock are built to address all these issues as compared to annually cropped land that is tilled.

The third issue levied at livestock agriculture is its contribution to Greenhouse Gas (GHG) emission.

Place said animal agriculture is responsible for approximately four per cent of GHG emissions and plant agriculture and cropping sit at roughly five per cent. Edible food waste, which sits between 30 and 40 per cent, accounts for 1.7 per cent of methane production in landfills.

“Think about all the impacts of producing food and never actually nourishing anyone,” Place said. “But then, at the end of life of that food waste, we potentially can produce methane gas in landfills. It’s kind of a double whammy.”

Reducing waste is a missed opportunity to increase sustainability, she added.

From 1990 to 2017 the human population increased 42 per cent and GHG emissions rose 38 per cent. However agriculture land-use emissions dropped slightly and agriculture overall held steady, said Place. Energy, industrial processes and product use and waste have experienced growth year-over-year.

“We produce more food for more people (and) we’ve essentially held the emissions constant – that’s a good thing,” she said. “That’s a real positive of a relationship being able to nourish more people with less of an impact per unit of food.”

Can we eat our way out of climate change?

Place said moving to a plant-based diet may make some difference but it’s not as significant as plant-based protein marketing strategies make it out to be.

Two scientists calculated the effect on GHG if every person in the U.S. became vegan and all domesticated farm animals were removed.

“In this scenario what they found is you indeed would reduce greenhouse gas emissions in this extreme scenario by 2.6 percentage points,” she said. “And in this scenario, you would actually make more pounds of food and more calories, that would be available in the U.S. food system.”

The challenge, said Place, is there wouldn’t be enough essential micronutrients such as vitamin B-12 coming directly from food because there were no animal-sourced foods.

Place said as things stand the removal of all domesticated farm animals wouldn’t eradicate the four per cent GHG emission, but it would increase the need for synthetic fertilizers for crops and legumes to provide nitrogen and plant-based protein for human consumption

“There’s no free lunch, there are consequences,” she said. “And essentially this rebound effect is why the total decrease of emissions is only 2.6 percentage points.”

About the author


Diana Martin

Diana Martin has spent more than two decades in the media sector, first as a photojournalist and then evolving into a multi-media journalist. Five years ago she left mainstream media and brought her skills to the agriculture sector. She owns a small farm in Amaranth, Ont.



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