The planet on your plate

When you think about ways to pare down your carbon footprint, certain things come to mind. You could ditch the electric water heater and go solar instead. Alternatively, you might forgo the flight to Europe and subscribe to GreenPower. Less well-known is the sizeable contribution of food purchases to each individualâ€™s total greenhouse emissions in the form of carbon dioxide, methane, nitrous oxide and fluorocarbons.

Fortunately there are ways to modify our diets to cut back on these gases and help tackle a range of other environmental issues. In the UK, Canada and Sweden, consumers are now able to make use of carbon labels on food products as a means of cutting their carbon footprints. They will probably be arriving in Australia, too, when enough people demand them.

Meat, dairy and some alternatives

Among items in the shopping basket, animal foods are responsible for some of the highest emissions, and an average familyâ€™s meat consumption can contribute more to global warming than the manufacture and running of a four-wheel-drive vehicle. The UN Food and Agriculture Organizationâ€™s 2006 report Livestockâ€™s Long Shadow estimates that the rearing of livestock produces 18 per cent of the worldâ€™s greenhouse emissions, more than all transport sectors combined.

As meat products go, from a greenhouse perspective beef is the biggest emitter, followed by pork, with chicken the least of the three. Another major meat-related issue is its sometimes huge water footprint. Professor Wayne Meyer of the University of Adelaide has estimated the â€œembodied waterâ€ for one kilo of Australian beef at 50,000â€“100,000 litres. Among dairy products, cheese is the most greenhouse-intensive, with milk the least.

Feedlots, which are widely used for raising Australian beef, chicken and pork, have a sizeable ecological footprint of their own. Their large appetite for grain feeds consumes land, energy, water and chemicals, while the fertiliser use causes extra emissions of nitrous oxide, a greenhouse gas with about 310 times the global warming potential (GWP) of CO2. The wastes generated can present a huge disposal headache and may emit the toxic gases hydrogen sulphide and ammonia.

For those who still like the idea of eating a steak, grass-fed beef has the advantage of cutting out the animal feed. Unfortunately, the benefits are not so clear-cut, as grass-fed cattle emit significantly higher quantities of methane, a greenhouse gas with a GWP of 21. An Australian study released early this year indicates that overall greenhouse emissions from grass-fed beef are higher than feedlot beef, although it omitted the huge potential for carbon sequestration on beef pastures, which some believe would tip the balance back towards the grass-fed camp.

Also, cattle should eat grass instead of grain. When they are fed corn in feedlots they require extra antibiotics and can experience a sensation similar to heartburn due to the acidity of corn and feedlot bloat, which is caused when the rumen (part of the cowâ€™s digestive system) fills with gas that cannot be released. This has the potential to suffocate the animal.

Seafood choices

The Australian Marine Conservation Society (AMCS) produces a Sustainable Seafood Guide that is downloadable from the groupâ€™s website for a cost of $9.95. Among the species it suggests avoiding are orange roughy (perch), imported prawns, farmed Atlantic salmon, shark (or flake, often used in fish and chips) and gemfish. Recommendations include barramundi, blue-eye trevally, hoki, bream, mullet and snapper.

Today, half of all fish sold on the world market have been farmed and this share is growing rapidly. While fish farming appears to be a good way to bring the industry onto a sustainable footing, there are some unresolved issues, including the question of feed. In order to grow healthily, fish need a diet rich in fishmeal or fish oil. Generally, fishmeal is sourced from the more abundant, less valuable wild-caught species, but over time their stocks, too, are likely to become depleted.

When fishing boats travel long distances to go after deep-sea fish, such as tuna, large quantities of fuel are consumed in the process. In March, Greenpeace issued a guide that ranks the different tuna brands based on a range of criteria, including clear labelling, avoiding overfished species, and fishing methods that minimise incidental bycatch such as turtles, sharks and juvenile tuna. The highest rating was given to Greenseas.

Going organic

Most food shoppers who are trying to minimise their environmental impact will probably be already buying items that are certified organic. In addition to often tasting better and having higher levels of some important nutrients, organic food has numerous ecological benefits, the greatest perhaps being its avoidance of synthetic fertilisers. These require large quantities of natural gas to manufacture and are linked to increased soil emissions of nitrous oxide.

Organic agriculture naturally maintains soil fertility and encourages biodiversity, while avoiding chemical pollution and minimising soil erosion. Genetic modification, irradiation and the use of nanoparticles are all banned. There are high animal welfare standards, and animal products are guaranteed free from antibiotics and hormones.

Essentially, various questionable practices pursued by much of the food sector are avoided under one single umbrella, saving consumers the need to direct numerous enquiries to food companies.

If you are not in a position to buy a lot of food under an organic label, conventionally grown fruit and vegetables with the highest levels of chemical residues tend to be apples, celery, grapes, green beans, kiwifruit, nectarines, tomatoes and strawberries. The most recent national pesticide residue data is from the 20th Australian Total Diet Survey, carried out back in 2003.

Fiddling with our food â€” genetics, irradiation and nanotechnology

Very few controversial and potentially dangerous technologies have so far failed to make it to the marketplace, and genetically modified food is no exception. Crops that may be affected in this way are soya, corn, cotton and canola (the Big Four), which may also be used to produce a range of ingredients including fructose, maltodextrin, lecithin (E322), modified starch and xanthan gum (E415.) Both GM cotton (used for cottonseed oil) and canola are grown in Australia.

While Australia does require labelling of GM foods, in practice there are several loopholes that exempt nearly all food derived from a GM origin. These exclusions include foods that are refined, feed used for animals, and an unintentional contamination threshold of 1 per cent. More information about companiesâ€™ GM policies is available from the Greenpeace True Food Guide, available in a pocket version or as a longer online listing.

Food irradiation is the practice of exposing food to high doses of ionising radiation from nuclear material as a means or preserving it and killing pests. Health concerns include the destruction of vitamins and the creation of novel compounds whose effects are little understood. Australia has three irradiation plants, all run by the company, Steritech.

Labelling rules require all irradiated food products to be labelled. This may include the Radura symbol (a flower inside a broken circle) and the words â€œtreated with ionising radiationâ€ or the more misleading â€œtreated with ionising electronsâ€. In the case of bulk produce, there is no requirement to label the individual item, but it is necessary to put up a label on the shelf nearby. Foods that may be irradiated in Australia are herbs, spices and a range of tropical fruits that are consumed domestically and exported to New Zealand. The activist group Food Irradiation Watch has its own Irradiation-free Food Guide that can be downloaded online.

Nanotechnology involves very small particles at the atomic or molecular level whose unusual properties are harnessed for a range of specific effects. Groups within the scientific community have expressed concern at the global regulatory vacuum surrounding this new technology, the potential for damage to health, and the growing number of consumer products containing these particles, including food, that are on the market.

In the marketplace, nanoparticles are far more likely to be used by multinationals than small- to medium-sized food companies. According to Friends of the Earth Australia, the giants Kraft, NestlÃ© and Unilever have all declined to say whether their ranges contain â€œnanofoodsâ€. However, it has been confirmed that nanomaterials are used in Cadbury chocolate wrapping. Product types to watch include diet replacement milkshakes, cooking oil, tea, vitamin-fortified fruit juice and food additives sold for use in processed meats, soft drinks, bakery and dairy products.

As no nano-free shopping guide has so far appeared, other than buying organic, the only avenue for concerned consumers is to call food companies, express their views and ask them to state in writing whether or not they use these ingredients. If no response is received, you may want to draw your own conclusions.

Is it forest-friendly?

Several food items in your trolley might be contributing the losses of the worldâ€™s forests and, if emissions from food were calculated holistically, this deforestation would also enter the equation. These foods include:

Beef sourced from Brazil. Otherwise, beef products from Europe might have been fed soya from deforested areas of South America.
Soya, which is a particular deforestation problem in Paraguay.
Palm oil, most of which is sourced from recently established plantations in Indonesia and Malaysia. The resulting loss of rainforest is a threat to the survival of the orangutan.
Rice, if it is grown in South-East Asia.

Global or local?

In the early 1990s, the term â€œfood milesâ€ was coined to indicate the total distance an item of food travels before it reaches the consumer. As the world economy has become more globalised, food is transported significantly longer distances than was the case 30 years ago. Environmentally, this matters because of the associated CO2 emissions, and, although the food miles are not the primary source of food-related greenhouse emissions, they need to be taken into account.

Air freight is by far the worst option, with figures from the UK estimating that per unit of distance it is 177 times more greenhouse-polluting than shipping. Some British supermarkets label air-transported items with a plane sticker, but no equivalent system exists in Australia. Imported foods most likely to be air-freighted are fresh seafood, fruit and perishable vegetables such as onions and snowpeas. If buying seafood from overseas, frozen might be a better choice.

Food miles can be lowered by various local food strategies that have the added bonus of increasing the resilience of a community against the arrival of peak oil. Solutions include farmersâ€™ markets, Community Supported Agriculture, urban farming, community gardens and growing your own in the backyard.

From processing to distribution

One way to follow a low-impact diet is to cut down on processed foods, which have a higher embodied energy than whole foods. As a rule, avoiding food packaging is preferable to recycling it, and the most energy-intensive packaging types are steel and aluminium cans. Aluminium can be very efficiently recycled, though.

Eating food when it is in season results in improved nutrition and flavour. The abundance of foods grown in Australia makes eating seasonally easier than in many other countries, which are more dependent on imports. Seasonal food choices reduce the need for the energy-intensive refrigeration in cold stores that is required when fruit and vegetables are sold out of season.

Driving to the shop or supermarket represents a significant chunk of the environmental impact from food buys. Having food delivered is a good environmental choice that reduces the number of kilometres driven, and one avenue is via Community Supported Agriculture organic box schemes.

Cutting food waste

Every year, the average Australian wastes about 145kg of food, representing about 20 per cent of all edible purchases. Cumulatively, this represents a large and unnecessary contribution to foodâ€™s significant ecological footprint. Often food that at first sight appears to have reached its date is fine to eat: â€œBest beforeâ€ indicates when it is likely to taste the best and has no bearing on safety. However, it is wise to stick to the â€œUse byâ€ date, particularly for meat and dairy products.

Unfortunately, a vast quantity of food is wasted before it reaches the consumer due to various inefficiencies. Supermarkets, in particular, believe consumers want to see produce of a uniform size and shape, in turn generating massive amounts of waste upstream. Go out of your way to buy strangely shaped fruit and vegetables when you find them. Where food is not used, it will generate methane emissions if sent to landfill. Better options are a compost bin, worm farm or to ask your council to start a green waste collection service.

To meat or not to meat?

In February 2010, the release of a World Wildlife Fund study, called How low can we go: An assessment of greenhouse gas emissions from the UK food system and the scope for reduction by 2050 created a considerable amount of debate about the benefits of choosing a vegetarian over an omnivorous diet. One argument advocating the reduction of meat in our diets says livestock farming is a major source of harmful greenhouse gases and a great waste of water. â€œRemoving meat from the diet and replacing it with plant foods with similar protein content reduces the carbon footprint of diet by one fifth,â€ says one of the studyâ€™s authors, Dr Murphy-Bokern. â€œRemoving all animal products removes nearly a third.â€

A counter-argument, however, holds that replacing meat with foods such as soy, chickpeas and lentils would, in fact, increase the amount of land cultivated, raising the risk of forests being destroyed and resulting in poor soil conditions if organic farming methods are not used. Further, most crops deplete soil fertility but farming livestock helps to maintain soil health and vitality. â€œThe grazers disperse the seeds and burrs of grasses, imprint seed into the soil and fertilise and sink carbon with their waste and decomposition,â€ writes Deborah Newell, of The Hunter Gatherer Dinner Club.

The pro and con arguments can be very involved and very confusing as each camp skews the findings of the other. If youâ€™re not sure which way to turn, try to include a few meat-free meals each week and find a balance that best suits you.

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