Food emissions - what's the damage?

Jodie Humphries

When buying your weekly shop, do you consider where your food has come from to reach your plate, and what damage food emissions are causing? If you don't consider the damage food emissions cause, then you aren't the only one.

How your food is grown, stored, transported, processed and cooked can all influence how it impacts climate change and the environment. Between 1968 and 1998, world food production increased by 84 percent and the population by 91 percent, but food trade increased 184 percent.

In the UK, food travels 30 billion kilometres each year. This includes imports by boat and air and transport by lorries and car. Food transport is responsible for the UK adding nearly 19 million tonnes of carbon dioxide to the atmosphere each year. Over two million tonnes of this is produced simply by cars travelling to and from shops.

When looking at the damage that's being done to the environment and resulting climate change, the distance our food has travelled to our plate is usually seen as the culprit, but that isn't necessarily the truth.

In fact, transportation accounts for only 10 percent of the emissions associated with Britain's food chain.

One of the most common items in a shopping trolley - apples - seem like a green option every time, but this isn't necessarily true. In Britain, if you see an apple with a little Union flag sticker on it, you'd think that this apple that is the most environmentally friendly, wouldn't you? Well, you'd be wrong.

Those British apples are likely to have been in cold storage for seven months, since they were harvested in the autumn. So, technically, you could be doing the environment a lot less damage if you buy an apple that's made its way over from New Zealand.

In the US, in 1870 almost all the apples consumed in Iowa were produced locally, but a little over a century later that number had dropped to 15 percent.

In developed, industrial nations, food appears to be travelling further to reach consumers. The inference is that many industrialised countries no longer rely on their own farmers to fully supply a number of food items. International food trade is increasing more rapidly than increases in population or food production.

An ever-growing proportion of what Americans eat is produced in other countries, including an estimated 39 percent of fruits, 12 percent of vegetables, 40 percent of lamb, and 78 percent of fish and shellfish in 2001. The typical American's prepared meal contains, on average, ingredients from at least five countries outside the United States. It is estimated that the average meal in the US has traveled 1,500 miles from the farm to the plate.

Why is this cause for concern for the distance food travels?

• This long-distance, large-scale transportation of food consumes large quantities of fossil fuels. It is estimated that we currently put almost 10 kcal of fossil fuel energy into our food system for every 1 kcal of energy we get as food.

• Transporting food over long distances also generates great quantities of carbon dioxide emissions. Some forms of transport are more polluting than others. Airfreight generates 50 times more CO2 than sea shipping. But sea shipping is slow, and in our increasing demand for fresh food, food is increasingly being shipped by faster - and by more polluting means.

• In order to transport food long distances, much of it is picked while still unripe and then gassed to "ripen" it after transport, or it is highly processed in factories using preservatives, irradiation, and other means to keep it stable for transport and sale. Scientists are experimenting with genetic modification to produce longer-lasting, less perishable produce.

Importing in California

In California, where agricultural commodities are one of the top exports, it is ironic that so much food is being imported from other states as well as overseas. Some of these imports are because people expect to have foods available year-round instead of seasonally. In other cases, imports are competing directly with locally grown produce.

Imports by airplane have a substantial impact on global warming pollution. In 2005, the import of fruits, nuts, and vegetables into California by airplane released more than 70,000 tons of CO2, which is equivalent to more than 12,000 cars on the road.

An article by the Center for Urban Education about Sustainable Agriculture tells how the sugar packet you open to pour in your coffee while seated in a café in Hawaii has traveled about 10,000 miles, even though the sugar cane field is a mile away. That's because the sugar cane is processed in California and packaged in New York. Rather than being an exceptional case, this is more often the norm in the food processing industry.

Food emissions left by a cheeseburger

The CO2 emissions involved in the production of beef are considerable. Jamais Cascio did a detailed study on the carbon footprint of a cheeseburger. The conclusion is that the entire process, from growing the grain, to feeding the cattle, to cooking the cheeseburger, generates between 3.6 and 6.1 kg of CO2 per burger. Based on average consumption per person estimates in the US this amounts to a total of between 65 million and 195 million annual metric tons of CO2. To make the numbers more meaningful, Cascio converted this to the equivalent of between 6.5 and 19.6 million SUVs on the road.

Burgers are common food items for most people in the US. Americans eat about 13 billion hamburgers a year. If you put all those burgers in a straight line, they would circle the earth more than 32 times.

Americans currently spend about US$134 billion dollars per year on fast food - more than they spend on college education, computers, software or new cars.

Energy Use in the Food Sector estimates that a single cheeseburger amounts to somewhere between about seven and 20 megajoules (the range comes from the variety of methods available to the food industry).

Choosing local food cuts food emissions

Choosing food that is local and in season means it does not have to travel so far. Reducing food miles can have a dramatic effect on reducing carbon dioxide emissions.

How far your food travels has serious consequences for your health and the climate. People are rediscovering the benefits of buying local food. It is good for your local economy because buying directly from family farmers in your area helps them stay in business. And by buying local, it means that your food isn't travelling long distances by planes, trains, trucks, and ships, which all consume energy and spew pollution that contributes to global warming and unhealthy air quality.

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