Answer:
Sustainability refers to activities that can continue without depleting nonrenewable resources. By locally producing food, shipping costs are reduced. Shipping costs involve the use of fuel (gasoline and diesel), materials (boxes and plastic bags), equipment (machinery and trucks), etc. Many of these costs require the use of nonrenewable resources, e.g. oil by-products and metals, so reducing their use helps the environment.
Economically speaking, local food production helps to lower food costs, local farmers are benefited and more money stays in the local economy. Globalization shrunk the world, so producing food locally may apply to a region surrounding a city or a whole country, and the large the net exports (exports - imports) of a region or country, the better.
