How much do food miles contribute to greenhouse gases?

It's very difficult to tell. Food miles means the amount of greenhouse gases are used to bring your food from farm to table. It doesn't make sense to buy Apples that are grown on the other side of the world if you can buy Apples grown in your own country. Transport emits carbon dioxide pollution.

However, it isn't always as simple as that. Beef, for example, can use a vast amount of water and grain to feed and fatten a beast. The carbon footprint of this kilogram of beef from your own country may be larger than that of a kilo of beef from the other side of the world that was raised with sustainable agricultural methods, despite being flown to you in a refrigerated plane.