By Emma Johnston
Seventy-five percent of all arable land is used to support animals other than humans. However, it takes less land to grow crops that humans can directly eat than it does to raise cattle, sheep and other animals, researchers say.
Prof. Christine Costello, University of Missouri, bioengineering, a former postdoctoral researcher in ecology and evolutionary biology at Cornell, found that the United States could both trim its population’s waistlines and reduce its environmental impact by swapping some of its meat consumption for consumption of vegetables, milk and eggs.
According to Emily Cassidy grad, University of Minnesota, growing crops instead of raising animals could feed as many as four billion more people.
Costello compared greenhouse gas emissions, land use and use of nitrogen in soil associated with different diet types. These diets include the average American diet, the omnivore, diet recommended by the United States Department of Agriculture, a Demitarian diet, which reduces average meat consumption by half, a ovo-lacto vegetarian diet that includes eggs and dairy and a vegan diet.
Costello used a life-cycle analysis to measure the environmental impact, land use and nitrogen and fertilizer input necessary for each diet at all stages of production.
According to Costello, it takes 4,150 square meters of land to produce all the food for an average American adult for a year, 3,370 square meters for the recommended omnivore and 890 square meters for the ovo-lacto vegetarian. This means that with the same amount of land required to feed the average American, almost five ovo-lacto vegetarians could be fed.
Increasing trade, however, complicates the conversation of food production, according to Costello. If a farm in the Midwest exports goods to the coastal U.S., is it fair for the Gulf States to incur the bulk of environmental damages? With problems like nitrogen pollution, should environmental harm be attributed to the exporter or the consumer?
Costello said that nitrogen pollution does not seem to be an issue because nitrogen is an invisible gas.
“Nobody’s seeing the environmental impacts; it’s a problem for another region,” Costello said.
Nitrogen use in farming is a double-edged sword, it both improves yields because it is a necessary soil nutrient, but too much can cause environmental problems such as algal blooms.
“The green revolution has done amazing, great things for humanity, but now we’re dealing with the dead zone in the Gulf of Mexico or groundwater with really high nitrate levels,” Costello said.
According to Costello, the average U.S. diet requires twice as much nitrogen as a vegetarian dietiet.
As a leading food producer for the world, the United States has decreased its beef consumption in recent years, but production of beef has not followed this trend because the United States exports what it does not eat to other countries.
According to the USDA, the average person in the U.S. still eats twice as much protein than is recommended, and more than half of that protein comes from meat. According to Cassidy, this helps explain why it takes 16.1 hectares to feed a person in the U.S. but only 6.5 hectares to feed a person in India.
According to Costello, food waste in the U.S. is also a problem. Close to half of all fruits, vegetables, and dairy products, 35 percent of poultry and 20 percent of beef are wasted at the consumer level, according to the USDA.
Costello advocates reducing food waste by suggesting that individuals investigate what is being grown in the first place and what implications thier food choices have for nitrogen pollution and improving health.
“Sustainability is about being where we’re maximizing human well-being, where we’re not destroying the ecosystems that we need for food and not constantly facing nutrient-related illnesses, whether malnutrition or over-nutrition,” Costello said. “I wouldn’t want to take away from the ability of a child who’s malnourished to eat something that’s really nutritious like milk or beef. That’s not sustainable.”