Climate change and dietary choices

Carlsson-Kanyama A (1998) "Climate change and dietary choices - how can emissions of greenhouse gases from food consumption be reduced?" Food Policy, vol 23, no.3/4, pp.277-293

The study looks at a selection of foods: pork, rice, dried peas, tomatoes, carrots and potatoes.

It finds that pork and rice produced the highest GHG emissions, followed by tomatoes. Dried peas were the least GHG-intensive of all the foods. It also notes that CO₂ and energy use is an inadequate measure of food chain emissions since methane and refrigerant emissions are very considerable. It notes that a 'critical' life cycle stage for one crop may not be so critical, relatively speaking, for another.

The study also points out that for food, the functional unit of measurement is very important. It compares four sample diets made up of various combinations of the foods studied to produce diets classed as: exotic non-vegetarian (pork, rice tomatoes), domestic non-vegetarian (pork, potatoes, carrots, peas) exotic vegetarian (rice, tomatoes, peas) and domestic vegetarian (peas, carrots and potatoes). Carlsson-Kanyama then measures GHG emissions in terms of kg of protein, beta carotene and calories that the four different diets provide.

The study concludes that the domestic vegetarian diet produces the lowest level of emissions for the highest level of nutrients, followed by the domestic non vegetarian diet. Seasonality is highlighted as an important indicator of GHG sustainability.