One of the most often heard reasons for buying local food is the need to reduce the carbon footprint of the products that nourish us. The carbon footprint is the amount of carbon dioxide (and other greenhouse gases) required to produce a unit of food. The more greenhouse gases circulating in the upper atmosphere, the warmer the Earth’s surface becomes and the more susceptible our planet is to widespread climate change.
Greenhouse gases come from a variety of sources when it comes to food production and transportation: methane production from ruminating cattle, nitrous oxide emissions from fertilizers and manure, and carbon dioxide production from fossil fuels used on the farm and in transportation of food. Studies suggest that only 10 percent of the fossil fuel emissions come from the farm. The other 90 per cent is needed for packaging, transportation and marketing of the farm products.
How does buying locally-produced food help reduce our carbon footprint? Due to the high costs of indiscriminate fertilizer application, smaller farms are more likely to only use it on an as-needed basis, which leads to complete nitrogen absorption in the growing plants and less release into the atmosphere. Agricultural practices that sequester carbon in the soil have traditionally been used on family farms and are gaining recognition for their environmental benefits. They include avoiding summer fallow, tilling less intensively, including forage crops in rotations; and planting marginal lands to permanent grass or bush. Such routine management of soils is more difficult on large-scale industrial farms that produce monoculture crops year round.
If you have recently purchased a plastic container of spring mix lettuce in the grocery store, have a good look at the ratio of plastic to actual product. A 312g package of spring mix is really 75g of plastic packaging and 237g of food. A great deal of energy is spent creating the plastic and packing the food into it. When transported on trucks, these plastic rectangles require far more space than large bags of lettuce, thus creating a higher fuel to container ratio.
On the other hand, local lettuce makes a shorter journey to the farmers’ market or retailer in trucks with more space devoted to food than packaging. At the most, your lettuce will be popped into a small plastic bag or, more likely these days, a reusable shopping bag. Like many more locally available fruits and vegetables, this lettuce has demonstrated a smaller carbon footprint by reducing fuel and packaging requirements, and is therefore a far more environmentally responsible choice.
While this choice may be easier in summer, what do you do in winter when Ontario lettuce production is still a few months away? A good start when shifting to buying local is to always choose seasonally available foods over their imported cousins (for example, buy local strawberries instead of U.S. imports in July). The next step is to reduce your consumption of out of season produce and to substitute locally available fruits and vegetables. For example, red and green cabbage harvested in the fall is available throughout the winter and makes crunchy, healthy salads. Try substituting other raw root vegetables as the building blocks for winter salads – carrots, beets, parsnip, and celeriac all provide healthy colour and flavour and can be enhanced with local apples, onions, garlic, honey and cider vinegar. Once in a while, a green salad may make it to your table while the snow swirls around outside, but it has now become a treat rather than standard fare. Shifting to a seasonally-based diet is not only an environmentally sound decision, it’s nutritionally appropriate as well.