Agriculture’s role in climate change was a central topic at the United Nations Climate Summit in New York last month. The drought in California has been a stark illustration of how much water is required to produce the fruit and vegetables that consumers increasingly demand, and there is a growing awareness about how food waste and animal husbandry generate pollution.

Image Shoppers at a Walmart in Los Angeles. Credit... Kevork Djansezian/Reuters

More and more companies are trumpeting their “sustainability” efforts, having realized that consumers care about the impact products have on the environment, and that acting to mitigate that impact can be profitable.

“Walmart’s food policies and practices have a tremendous impact given its size,” said Margo Wootan of the Center for Science in the Public Interest.

Walmart’s effort to enhance sustainability has four legs: reducing the overall cost of food, including its environmental footprint; increasing access to more nutritious food; making it easier for its customers to eat healthier foods; and improving food safety, with greater transparency about where food comes from and how it is produced.

The company says it has been working with a variety of partners, including nonprofit groups, food manufacturers like General Mills and PepsiCo, and agricultural businesses like Monsanto and Cargill. Walmart and General Mills, for example, are sponsoring a challenge that will reward farmers who show the most progress in reducing emissions through better use of fertilizers.