Analysing the carbon footprint of food : insights for consumer communication
Sammanfattning: In Europe, food consumption is responsible for approximately 30% of total greenhouse gas (GHG) emissions. There has been huge interest in estimating the carbon footprint (CF) of food products, i.e. the total amount of GHG emitted during the life cycle of the product, and communicating these to consumers to enable them to make informed choices. This thesis provides additional knowledge of several related issues regarding calculating and acting on the CF of food products in order to facilitate the design of effective consumer communication strategies. The uncertainty in the CF of Swedish potatoes and pasta was established to investigate the detail to which food CF can be determined. For a well-defined geographical area the uncertainty was in the range ±10-30%, indicating that the CF uncertainty for more complex foods or foods with a more unspecific origin is considerably higher. Emissions of N₂O from soils dominated the emissions and uncertainties, and yield was an influential parameter for all crops. Possible risks of pollution swapping when acting on CF were investigated in the case of meat production. For meat from monogastric animals, in most cases the CF functions as an indicator for land, energy and pesticide use, and for acidification and eutrophication potential, but for ruminant meat there are possible conflicts with biodiversity, energy and pesticide use. In an attempt to develop a tool that communicates the CF of meat in an efficient way, while highlighting important trade-offs, a criteria-based meat guide based on the knowledge gained was developed. A critical review of CF labelling from a consumer perspective showed that obstacles known to prevent purchase of organic foods, e.g. perceived high price and strong habits, apply equally or more so to the purchase of CF labelled foods. Hence, CF labelling of food in a retail setting is of limited effectiveness, but CF values are important in business-to-business communication, in policy development and for developing efficient and scientifically justified consumer communication messages. Quantification of the reduction potential from a commonly recommended option, 'eating seasonal', showed that consuming tomatoes and carrots seasonally in Sweden could reduce the CF by 30-60%. This is a substantial reduction for these products, but a small reduction in view of the total GHG emissions from the complete average diet. This illustrates the importance of calculating CF values of food and setting the results in perspective.
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