Food

How School Food Affects the Environment - Upload Knowledge


“Food miles” are one way food affects the environment


Transporting food is one of the fastest-growing sources of greenhouse gas emissions, according to the World Watch Institute. Each year, 817 million tons of food are shipped around the planet. The result is that a basic diet of imported products can use four times the energy and produce four times the emissions of an equivalent domestic diet!

Food Miles represent the distance your food travels from where it is made to where it is eaten. According to the National Sustainable Agriculture Information Service, this distance has been increasing over the last fifty years, and now processed food travels an average of 1,300 miles.

The term “food miles” for a food’s impact on the environment may soon be replaced by the more accurate “life cycle carbon footprint,” according to the BBC. This new term would encapsulate more than just transportation, but everything a food product goes through that contributes to its carbon footprint.

Food miles specifically affect the environment by how they are related to emissions of greenhouse gases from transportation vehicles, most notably carbon dioxide. Greenhouse gases contribute to climate change. For more on this issue, see our Climate Change Section.

However, “food miles” are not the only way our food contributes to climate change. In fact, Chris Weber of Carnegie Mellon University, lead author of a recent study on food miles published by Environmental Science & Technology, claims that 83% of food’s greenhouse gas emissions come from the growing and harvesting of the food. The BBC adds that agricultural practices, processing, storage, and the way we shop for food all play a role in food’s carbon footprint. Agricultural processes alone account for 21% of the food’s energy use according to the Earth Policy Institute, not to mention another 16% for food processing, 7% for packaging, and 4% for retailing. For example, Fresh Energy explains that producing a two-pound box of cereal uses a half-gallon of gasoline worth of energy. Furthermore, if the product that’s made is something like a frozen TV dinner or ice cream, it needs to be kept chilled or frozen long before it ever reaches a consumer. Keeping a product chilled or frozen requires energy and therefore releases carbon emissions, sometimes enough emissions to exceed those produced by transporting the item.

Currently, 9% of America's energy consumption is used to produce, process, and transport our foods.

Food miles can also be a cloudy issue if the specific local food in your area happens to be grown out of season or in an unsustainable, energy-intensive way. For example, maybe a lot of your local food is grown in a greenhouse that happens to use extra energy during colder months and also uses a lot of pesticides. If this was the case, which would be better for the environment: buying that local food or buying imported food grown more sustainably somewhere else? Despite the potential complications and despite the fact that there is more to food’s carbon footprint than transportation, you can still make a positive difference by trying to buy locally. According to the recent book Animal, Vegetable, Miracle, if everybody in America ate just one meal of local and organic food per week, we would cut the nation’s oil consumption by 1.1 million barrels a week!

If you still want to learn more about food miles, check out these links from the National Sustainable Agriculture Information Service (ATTRA).

It's not just the food! Preparation of food in your school affects the environment in other ways. For example, is your kitchen energy-efficient? Dishwashers, grills, and even hotplates use a tremendous amount of energy. For tips on improving energy use with all appliances in the kitchen, check out our energy-efficiency tips. How about the efficiency of your water use? For tips on increasing water efficiency, check out our water chapter.


Some types of food are better than others in terms of food miles and carbon life cycles

Meat and dairy create the most “food miles” for production. The BBC reports that meat is the most energy-intensive of all types of food, while also using more water and producing more waste. For example, producing a tomato only requires 13 liters of water, while producing a hamburger requires 2,400 liters of water. And as far as waste, cows give off methane which contributes to global warming, and require more fossil fuels to raise.

Although it’s not our place to challenge everyone to become vegetarians, cutting out just a portion of meat and dairy from your diet can make a huge difference! In his recent study, Weber of Carnegie Mellon University, explains that replacing red meat and dairy with chicken, fish, or eggs for just one day a week can reduce one’s greenhouse gas emissions substantially, having the effect of driving 760 miles less per year. And if you were to switch to only vegetables for that one day a week, it would save the equivalent of 1,160 miles of driving!

Buying local food has security benefits too! Danielle Murray of the Earth Policy Institute points out that fluctuations in oil supply could send food prices soaring overnight. Depending too heavily on food shipped from far away may make us economically vulnerable.


Food production also impacts the immediate environment through the land surrounding it

The growing of food affects the health of the environment in many ways. Growing methods affect the quality of the soil and the quantity of the local water supply. Moreover, the way pesticides are used affects every level of the local environment. Finally, the way food is grown can even impact the health of specific species, both domestic and natural varieties.

Sustainable and organic farming usually have less of an impact on the health of the land. But, before we explain what sustainable and organic farming is, let’s get a sense of the ways modern farming can take a toll on its surrounding environment, shall we?

First, there are soil issues. Although healthy, nutrient-rich soil is essential for good crops, many industrial farming practices deplete the very soil they depend on. Ecotrust reports that in the United States, we are losing soil 17 times faster than it naturally regenerates. The result is that farms have to use more chemical fertilizers to replenish the soil’s nutrients. But in addition to replenishing soil, fertilizers can also negatively impact surrounding areas by being washed into local water-bodies where they spark high levels of aquatic plant and algae growth. Massive growth of these organisms can suck oxygen out of the water and make it hard for fish species to survive.

According to the UNEP, fertilizers containing nitrogen also increase the greenhouse gases in the air by increasing nitrous oxide emissions. The nitrogen-rich fertilizers enhance processes carried out by bacteria in the soil that result in nitrous oxide emissions. Danielle Murray of Earth Policy Institute also points out that fertilizers affect the environment in other ways before they even reach the farm, like by the oil and natural gas consumption required to mine, refine, and transport them, and the resulting carbon dioxide emissions from those processes.

Thankfully, there are alternatives to heavy fertilizer use, according to Ecotrust. For example, some farmers plant cover crops and leave crop residue on fields as ways to restore soil nutrients.

Another issue of modern farming is its heavy use of local water supplies. In some parts of the country, precipitation is frequent enough so that not as much water needs to be pumped from local aquifers and water-bodies. However, in other parts of the country that are drier, crops need extensive irrigation to grow. Irrigation by mechanical pumps has made it possible for farms to exist in the middle of the desert, according to Danielle Murray of the Earth Policy Institute. But, mechanical irrigation pumps often withdraw more water than the local environment can afford to use. How much water? A lot of water! In places like California and Oregon, Ecotrust reports that over 75 percent of water use goes to farms! For the dry land and dense population of California, that amounts to a deficit of 475 billion gallons a year for the state’s aquifers.

But, just like with the soil depletion issue, there are alternatives to heavy pumping for irrigation. Ecotrust explains that methods such as drip irrigation, which sends water directly to the soil through tubing, can reduce water use while at the same time increasing crop yields. The Earth Policy Institute adds that precision soil moisture testing can not only cut water use, but energy use as well. Of course, there are solutions that don’t even depend on machinery, such as leaving crop residues on the ground in order to minimize wind and water erosion and the loss of soil moisture. Non-mechanical solutions like this certainly reduce fuel use.

Next, there are pesticide issues. As we mentioned before, pesticides can affect human health negatively if ingested through food. In the same way that pesticides are not healthy for us to consume, they are not healthy for the local environment either.

What’s the difference between pesticides and herbicides?

There are many different kinds of “cides” and they all refer to a substance, usually chemical-based, that wards off some kind of unwanted pest. Usually they are designed to kill the pest. Sometimes “pesticides” is used as a general term to refer to all types of “cides”: insecticides, fungicides, herbicides, etc. Other times “pesticides” refer to just chemicals designed to ward off insects or rodents. “Herbicides,” on the other hand, are specifically designed to kill plants, usually weeds.

Pesticides or herbicides are dangerous to the environment because they are designed to kill organisms. Though pesticides are intended to kill specific organisms, many varieties of life share similar essential life functions and can thereby be affected. For example, if a pesticide is designed to disrupt a certain enzyme crucial to life in one type of organism, it may also disrupt that enzyme in all other organisms that use the enzyme. Because of this, pesticides applied in the open environment often negatively impact the local ecosystem, especially because pesticides don’t just stay on the farm where they are used, according to
Ecotrust. They can travel through the air, through streams and rivers from the farm, and around the world via the products they are applied to.

One of the most alarming characteristics of pesticide use is that it perpetuates itself. Ecotrust explains that using pesticides makes them less effective over time and therefore, greater amounts and greater concentrations of toxicity have to be used. In fact, their use has increased tenfold since the 1940’s even though the portion of U.S. crops lost to pests has increased, according to Ecotrust.

Why does more pesticide use mean more has to be applied in the future to get the same effect? It’s because pesticides kill off most of a species that can’t tolerate it. As a result, the only members of a species that survive are ones that happen to carry genes that make them more tolerant to the pesticide. Therefore, the new gene pool is full of pesticide-resistant organisms. It is natural selection at its best! The Union of Concerned Scientists explains the process in more detail, especially with how it affects genetically modified crops even more than traditional crops. As a result, many genetically modified crops require more pesticides than traditional crops.

And last, but not least, there are concerns about the impact genetically-modified crops have on our environment. Genetically modified food can adversely affect the environment in many ways. But, in order to fully understand the issues, it’s important to understand the perceived benefits of GM food over traditional food production. According to the WHO, genetically modified food is produced to be more resistant to plant diseases, insects, viruses, or pesticides and herbicides. The ultimate goal is for farmers to have a greater food yield and make food cheaper and/or longer lasting for the consumer. Additionally, some GM foods are intended to have a greater nutritional value. The Human Genome Project and Medline Plus both offer simple lists of the benefits and risks of genetically modified foods.

As far as environmental effects specifically, The WHO explains that one of the biggest concerns is when genetically modified species mix with wild populations. This happens by insects, birds, and wind carrying pollen from genetically modified plants to other locations, according to the Sustainable Table. As the Center for Food Safety explains, the mixing of GM species and wild species can negatively impact biodiversity by threatening the survival of various microbial, plant, and animal species. Furthermore, with the increase in genetically modified species, even the biodiversity of domestic varieties is declining according to WHO. Ecotrust explains that keeping traditional varieties of domestic species alive are important because those species carry traits that make it possible for them to adapt to new pests and changing climates. Many genetically modified species are designed specifically to resist particular pests and climates, but how will they fair with changes to these delicate conditions?

WHO also mentions a concern about how susceptible non-target organisms are to the modified food, such as insects. Some of the insects that could be negatively affected are beneficial insects, and other resistant insects could become more prevalent. Furthermore, creating new types of crops and dedicating massive land area to a modified species can be a huge risk because of the potential generation of new plant pathogens.

Finally, The Sustainable Table makes the point that one of the most unsettling characteristics of GM food’s impact on the environment is simply that its effects probably can’t be reversed. Unlike other types of pollution, such as chemicals and waste, genetic code has the potential to spread in all the ways that life does. So, if some of GM food production’s environmental effects prove detrimental, how will we back-track?

Because genetically modified food is such a controversial issue, we want you to have an opportunity to hear proponents and opponents argue their cases in their own words…

Opponent video

Proponent Video

Middle of the Road Video


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