If Americans Eat Vegan Half the Time, We Could Lower Diet-Related Emissions by 35 Percent

We know that eating animal products has a high environmental impact — but just how much of a difference would it make if Americans actually, significantly, cut back on meat consumption? A new study looked at just that, and found that if Americans replace 50 percent of the animal products they eat with plant-based foods by the year 2030, the country’s diet-related greenhouse gas emissions would go down by 35 percent. 

The study, “Implications of Future U.S. Diet Scenarios on Greenhouse Gas Emissions,” was commissioned by the Center for Biological Diversity and conducted by researchers from Tulane University and the University of Michigan. According to the study’s abstract, shared by University of Michigan’s Center for Sustainable Systems, the study looked at four projected scenarios for the U.S. by the year 2030: 

1. The average diet remains unchanged
2. Meat consumption increases (as the USDA predicts will happen between now and 2028)
3. 50 percent of meat, dairy, and eggs are replaced with plant-based options
4. 50 percent of animal products are replaced with plant-based options, except beef decreases by 90 percent (since beef has an exceedingly high environmental impact).

The current average American diet accounts for a diet-related carbon footprint of 5.0 kg CO2 equivalent per person per day — so in the first scenario, where diets stay the same, so would their diet-related carbon footprints.

In the second scenario, in which meat consumption increases, the average American’s daily diet-related carbon footprint would increase to 5.14 kg CO2 equivalent.

In the third scenario, in which half of all animal products are replaced with plant-based foods, there would be a 35 percent decrease in greenhouse gas emissions from the current diet. That diet would cause a diet-related carbon footprint of 3.3 kg CO2 equivalent per person per day. In total, that would save a total of 224 million metric tons of greenhouse gas emissions per year in 2030 — that’s the equivalent of taking 47.5 million cars off the road for an entire year, and it represents 24 percent of the total reduction the U.S. needs to achieve the goals of the Paris Agreement. Not to mention, if the U.S. were to gradually begin this process now, we could save an estimated cumulative 1.6 billion metric tons of greenhouse gas emissions over the next 10 years.

In that third scenario, red meat accounts for 36 percent of the diet’s total emissions. So in the fourth scenario, in which Americans replace 50 percent of their animal products with plant-based foods but 90 percent of their beef with plant-based foods, diet-related emissions would go down to 2.4 kg CO2 equivalent per person per day. That’s a 51 percent decrease in greenhouse gas emissions from Americans’ current average diet. 

“While a diet shift isn’t a silver bullet, it could play an important role in curbing climate change,” lead author Martin Heller told the University of Michigan in a statement. “This research shows that replacing only half of our animal-based food consumption with plant-based alternatives could account for nearly a quarter of the reductions necessary for the U.S. to meet a Paris Agreement target.”

“Moving the American appetite from our burger-heavy diet to plant-based eating is a powerful and necessary part of curbing the climate crisis,” Stephanie Feldstein, Population and Sustainability Director for the Center for Biological Diversity, said in a statement. 

“The coronavirus pandemic has exposed the meat supply chain’s vulnerabilities, but our food system faces even greater long-term threats from climate change," Feldstein continued. "We desperately need policymakers to support sustainable diets and a resilient food system.”

This is not the first study to highlight the strong link between the consumption of animal products and greenhouse gas emissions. In 2018, a landmark study out of the University of Oxford not only found that a vegan diet is the best way to reduce individual environmental impacts, but that if the entire world phased out meat and dairy, we could reduce worldwide farmland use by 75 percent.