By: Jenna Blumenfeld for Delicious Living

Sustainable eating is complicated. It’s time-intensive and confusing to compare the carbon footprint of, say, an organic apple grown a thousand miles away and trucked to your grocery store versus an organic cereal brand that participates in a carbon-offset program.

Choosing to buy and eat local food is a large part of the carbon-mitigation solution because local often eliminates the thousands of miles some food travels before it winds up on your plate. The idea of local food as an answer to global warming is not new. In 2006, food thought-leader Michael Pollan advised in The Washington Post that, given the choice, “Buy local over organic,” with the reasoning that many local farms are small, and small farms sometimes lack the funds to obtain a pricey USDA Organic certification. And in 2007, the National Resources Defense Council said, “In most cases, locally produced food proves the best choice for minimizing global warming and other pollutants.”

What does local mean?

But the government does not regulate “local,” as it does the USDA Organic label. It’s up to the retailer, restaurant or shopper to decide what local means. For one retailer, “local food” could mean food sourced within a certain mile radius from the store; to others it could mean buying from farms in the same county. To Shaun Donovan, co-founder of Provisions in downtown Harrisburg, PA, “local” means food produced within 90 miles of the store with a preference for PA Preferred Products.  Provisions sources as much local food as possible in the store, making exceptions just for tropical ingredients like spices, orange juice and avocados and to extend the season on fresh foods.  Care is taken though to get products from as close by as possible.

Provisions also partners with local vendors that implement sustainable practices.  For instance the main produce supplier recently installed a large solar array to reduce the amount of electricity they use in their distribution facility.  These practices also help to reduce the impact of operations and the overall delivery of product to the store.

Buying local caution

Just because a farm or food producer is located close to your home, that doesn’t necessarily mean they are an eco-conscious choice. Large-scale farming operations that use pesticides and fungicides could be a stone’s throw from your house; sugar-laden soda companies could be manufacturing across the street.

So although local is an important hallmark of sustainable food, it’s just one part of the solution. Farms must also be consciously managed, which often means adhering to organic or biodynamic practices, too, as chemical fertilizers can cause just as much damage to the environment as food that travels thousands of miles.

A recent study published in the journal Nature Plants chronicled the environmental footprint of a staple finished product, bread. While trucking the raw wheat to processing facilities and to the consumer largely contributed to climate change emissions, scientists found that bread’s worst environmental faux pas was from ammonium nitrate fertilizers. These agricultural chemicals are applied in large quantities—sometimes more than farmers actually need—and end up polluting waterways and turning into the greenhouse gas nitrous oxide.

The lesson

Both local and farming practices matter when it comes to being a better steward of climate change. To better understand your grocery store’s sourcing decisions, ask your retailer how it defines local. Some retailers consider “local” to be anything produced in their county or state, while others consider “local” to encompass products produced within 100 miles of their front door. Also, buy seasonal produce to increase the likelihood that fruits and vegetables were locally grown, and frequent farmers’ markets to support farmers in your community.