The spoiled milk, moldy vegetables and expired meat we discard when cleaning out the fridge make a surprisingly large contribution to global warming.
One-third of all food produced is wasted, a problem responsible for carbon emissions equivalent to all road transportation, said Elena Belavina, associate professor at the School of Hotel Administration in the Cornell SC Johnson College of Business.
Her newly published research suggests one strategy for reducing food waste’s environmental impact: Open more grocery stores.
“The more stores you have, the lower food waste is going to be,” said Belavina, an expert in operations management and supply chains. “Very small increases in store density can have a very high impact.”
For example, Belavina found that in Chicago, which she said is typical of many American cities, adding just three or four markets within a 10-square-kilometer area (about four square miles) would reduce food waste by 6% to 9%.
That would achieve an emissions reduction comparable to converting more than 20,000 cars from fossil fuels to electric power, Belavina reports in “Grocery Store Density and Food Waste,” published Jan. 30 in the journal Manufacturing and Service Operations Management.
And Belavina’s model, which incorporated data from the grocery industry, U.S. Census Bureau and other academic studies, found the improved store density in Chicago would have a bonus benefit: lower grocery bills. By trimming food waste and travel costs, consumers would spend up to 4% less.
“So it’s a big win for the environment and a big win for consumers,” she said.
Most big cities are well below their ideal density of grocery stores that would minimize food waste, the research determined. In Chicago, that would be about 200 markets within a 10-square-kilometer area – compared to 15 currently – but most of the benefit from reduced emissions would be achieved by about 50 stores. New York City, with its abundance of produce stands and neighborhood markets, comes closest to its ideal density.
Belavina’s own experience illustrates the tradeoff most consumers make.
As a graduate student in Paris, she picked up fresh ingredients from a market near her apartment, buying only what she needed each day. Later, living in Chicago, where she had to drive to a grocery store, she bought more groceries per visit and wasted more.
When consumers can purchase perishable goods nearby, she said, they shop more often but buy less each time, ultimately wasting less.
“There’s less food sitting at home,” Belavina said. “As a result, there is a much lower likelihood that something will be spoiled, and we’ll actually be able to eat all of the stuff that we’ve purchased before its expiration date.”
Most of the carbon emissions associated with food waste are embedded in its production. Reducing waste would trickle through the supply chain over time, Belavina said, so farmers would not produce too much food.
Food waste trapped in landfills further contributes to global warming by producing methane, a greenhouse gas whose impact, pound for pound, is more than 25 times greater than carbon dioxide over a 100-year period, according to the U.S. Environmental Protection Agency.
Increasing grocery store density could lead to more waste by retailers, Belavina found, but households are by far the bigger driver of food waste. “We at home throw away 10 times more food than the grocery stores,” she said.
Urban planners, city governments and activists should pursue policies encouraging an optimal density of grocery stores based on each city’s population, she said. Retailers’ sustainability plans should analyze how their store networks and supply chains contribute to food waste and emissions overall.
“We actually see some moves across the globe toward going a little bit back in time and reviving those small corner stores, mom and pop stores, smaller-format stores,” she said.
Consumers in areas lacking the optimal store density, Belavina said, should consider online shopping and grocery store delivery services.
“Any service that makes it more convenient and allows you to shop more frequently,” she said. “To reduce food waste, essentially what households need to do is bring less groceries home.”
Belavina’s research was supported by funding from the Jane and Basil Vasiliou Faculty Research Fund and the Neubauer Faculty Fellows program at the University of Chicago Booth School of Business.