How the concept of food miles hurt the planet
Food miles are defined as the distance that food travels from the field to the grocery store. This term was coined by Dr Tim Lang from London City University. It used to be simple. The further the food is away from you, the more ecologically unsound it is as it would have emitted lots more carbon dioxide via transportation (trucks, planes, trucks etc). This was nicely summarised in 2007 in an University of Alberta study – Organic Food Miles Take Toll on Environment.
Of course nothing is ever simple in ecology, where you get a myriad of inputs influencing the outcomes. So transportation is only one factor contributing to total emissions in food production.
As commented by Dr Gareth Edwards-Jones of Bangor University:
‘Working out carbon footprints is horribly complicated,’ says Edwards-Jones. ‘It is not just where something is grown and how far it has to travel, but also how it is grown, how it is stored, how it is prepared.’
And then you have to consider economy of scale. It probably cost you more to make your own icecream then to buy one
This article from Guardian sums it up nicely.
Ultimately it boils down to the type of food you eat. Meats (cattle especially due to methane emissions), will produce more carbon dioxide than vegetables and is the most energy intensive of all foods. 2,400 liters of water to produce 150g of hamburger compared to 13 liters for a 70g tomato.