Pause for thought
Sarah Murray, Straits Times 15 Dec 07;
THIS Christmas will probably be greener than any holiday in recent years. Greeting cards will be sent online. Carbon offsets might be fashionable seasonal gifts. So what should we be doing about Christmas dinner?
Some in the US are bound to suggest that buying ingredients only from local farmers would help reduce the carbon emissions associated with the festive dinners. This 'food miles' diet is a neat concept. The trouble is, the distance food is transported is not necessarily an accurate measure of its environmental impact.
For a start, consider the relative efficiency of different forms of haulage. If you look at fuel consumption per kilogram carried, an ocean-going vessel carrying thousands of containers (a single 20ft container holds about 48,000 bananas) does quite well, while in the case of an American family, a 16km trip to the farm in a big car to pick up a few bags of vegetables seems, in emissions terms at least, downright destructive.
And while it might seem logical that the further a food item travels, the more carbon emissions it generates, this turns out not to be so. When you count the energy used by harvesting and milking equipment, farm vehicles, feedstock and chemical fertiliser manufacture, hothouses and processing factories, transportation emerges as just one piece of the carbon dioxide jigsaw puzzle.
Take the potato chip, for instance. When Walkers, a British snack-maker, studied the carbon footprint of a packet of its chips, distribution represented just 9 per cent of the total. The greatest emissions came in storing and frying the potatoes.
Farmers store potatoes in artificially humidified warehouses, which take energy to run, generating emissions. Because of the way they are stored, the potatoes contain more water and take longer to fry, again generating more emissions.
And since farmers sell potatoes by weight, they have no incentive to drive off excess water. Changing the way potatoes are warehoused and sold could therefore significantly cut the carbon footprint of chips.
Obviously, calculating the carbon footprint of food is an extraordinarily tricky business. But only when we understand a food's energy use throughout its life cycle from seed to kitchen can we make intelligent decisions on where to start on cutting the greenhouse gas it generates.
Sometimes this might mean choosing products with far-off origins because the methods used to raise or process them are more environmentally sustainable than the nearby equivalent. But the local food movement is not only about the environment. Local food purchases, say 'locavores', also support local or nearby farmers. True enough.
But it depends on your perspective as to what constitutes a local farmer. Should we not consider supporting an African farmer for whom supplying richer markets with produce has provided a vital source of income - and who, by the way, often farms in a way that produces fewer emissions.
Perhaps the most powerful driver of the local food movement is its rejection of industrialised production. Yet feeding the world's 6.6 billion people, more than half of whom live in cities, is not possible without mass production. Rather than turning away from the big food companies, we should press them to find safer, healthier and more environmentally sustainable methods of supplying our dinner tables.
The 'food miles' concept has helped raise awareness of the environmental impact of one aspect of our lives: eating. Yet the potato chip example shows greening our food supply means we have to think more creatively.
The danger of going for the easy target of transportation is that we focus too narrowly and miss the bigger picture.
The writer, a contributing writer for The Financial Times, is the author of Moveable Feasts: From Ancient Rome To The 21st Century, The Incredible Journeys Of The Food We Eat.
