By Jason Daley
There's no way around it—everything in the grocery store, from nuts and kale to beef and apples, has an environmental impact. Fertilizer causes water pollution, farm fields can encroach on habitat, and a lot of carbon gets released when food is transported from one place to another. But it turns out not every stalk of broccoli or pound of Gouda has the same ecological footprint. A new study of food systems in the journal Science shows the same items sitting next to each other on the shelf can have radically different impacts.