Ditching meat and dairy is the most effective way individuals can lessen their impact on the planet, according to new data.
Reducing food’s environmental impacts through producers and consumers - the biggest ever analysis of farming's effect on the earth - shows that while livestock takes up 83 percent of farmland, it provides just 18 percent of calories - and 37 percent of protein.
In addition, the meat and dairy sectors are responsible for 60 percent of agriculture's greenhouse gas emissions.
According to the study, which consolidated data from more than 38,000 farms producing 40 different agricultural goods around the world, the environmental cost of producing the same goods can be highly variable.
"Impact can vary 50-fold among producers of the same product, creating substantial mitigation opportunities," says the report. "However, mitigation is complicated by trade-offs, multiple ways for producers to achieve low impacts, and interactions throughout the supply chain. Producers have limits on how far they can reduce impacts."
Analyzing the breadth of the data, scientists concluded that: "Most strikingly, impacts of the lowest-impact animal products typically exceed those of vegetable substitutes, providing new evidence for the importance of dietary change."
Speaking to The Guardian, Joseph Poore at the University of Oxford, who led the research, said: "A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gases, but global acidification, eutrophication, land use and water use.
"It is far bigger than cutting down on your flights or buying an electric car. Agriculture is a sector that spans all the multitude of environmental problems.
"Really it is animal products that are responsible for so much of this. Avoiding consumption of animal products delivers far better environmental benefits than trying to purchase sustainable meat and dairy."