We've all heard that buying locally-grown produce is better for the environment because of the fuel consumed to transport goods, but that isn't always the case. If you can buy locally-grown tomatoes in the middle of winter, it's likely because they've been grown in heated greenhouses over several weeks, which is far worse in terms of carbon emissions than buying tomatoes that have been transported from another country where they were grown without artificial heating. Indeed, the environmental impact of transportation is typically a drop in the ocean compared to the many different resources that go into producing our food. These resources will include the energy consumed to make it possible to grow crops in areas and seasons that are colder or drier than where they naturally grow, but also processing of food into more complex products like chocolate bars and ready-meals. As a general rule, the more processing involved, the more energy required, and this is a far more important factor to attend to in the supermarket aisle than whether something is produced locally.
