Possible adaptations in consumption patterns and associated tradeoffs

The consumption of meat and dairy comes together with large emissions of greenhouse gasses (Figure 12.5). Altering diets to reduce consumption of these products would theoretically reduce GHG emissions. (Refraining from eating meat and dairy would lead to a 50% decline of the CO2 equivalents related to food.) However, dairy and meat play important dietary roles with meat being important for protein supply and milk for its calcium. So just refraining from dairy and meat is not possible, replacements have to be found to fulfill the nutritional requirements of the human body. The design of these replacements is complicated as food also has emotional and cultural values. In the Kramer study mentioned earlier, options to reduce greenhouse gas emissions through changes in the consumption patterns are examined, taking the nutritional and social/emotional values into account.

Kramer (2000) designed 7 sets of changes in the menu (without changing the nutritional value of the menu) and calculated the reduction greenhouse gasses obtained with these changes. Table 12.2 shows a summary of the results.

Table 12.2 Possible changes in food consumption patterns and related reduction of the greenhouse gasses (in CO2 equivalent)


Description of the changes with respect to the present





20% less meat, replaced by vegetables



As set 1, and twice a week vegetarian meal



As set 2, and no glasshouse vegetables, replaced by import



As set 3, but replaced by locally grown



As set 4, and 20% less rice and pasta, replaced by potatoes



As set 5 and 20% less milk, replaced by coffee and tea



As set 6 and 20% less cheese, replaced by jams


Note: Data obtained from Kramer (2000).

Note: Data obtained from Kramer (2000).

Set 1 involves a 20% reduction in meat consumption. Since we eat more meat than is necessary, a 20% reduction is possible without introducing a protein shortage. In set 1 only the caloric value is replaced with vegetables. In set 2 the meat is replaced by a vegetarian alternative (cheese or a vegetarian burger). Since consumer research has shown that a change to complete vegetarian lifestyle is not feasible (Nonhebel and Moll, 2001) the analysis involves a vegetarian meal twice a week. This twice a week a vegetarian meal involves a larger reduction of the meat consumption than the 20% in set 1. However the production of the vegetarian replacements also leads to emissions of greenhouse gasses, so that the net gain is smaller (2.1%).

Set 3 focuses on glasshouse vegetables. Heated glasshouses require large amounts of energy to produce tomatoes, peppers etc. In warmer climates (Spain), these vegetables can grow in open air systems, hardly requiring energy. A change from glasshouse vegetables to imported open air vegetables is therefore an option. However, in that case the vegetables have to be transported from the production area to the consumer. When this extra transportation is included the change from glasshouse to import will involve a GHG emission reduction of 2.5%. Replacing glasshouse vegetables with locally grown open air vegetables leads to a far larger decline in emissions: 3.4%. This option seems promising (just replace the vegetables in the meal), however one should realize that such a change involves the use of other vegetables since not all vegetables can be grown in the open air. A change to locally grown 'open air' vegetables also implies large changes in seasonal menus. In the summer season not many changes are expected, but in the winter season the consumption of locally grown vegetables involves a menu with only cabbages, unions and carrots.

The change from rice and pasta to potatoes (set 4) had hardly any effect on emissions. With respect to milk and cheese some gain is expected. In the sets studied (6 and 7) the nutritional value is not replaced (the present consumption allows a reduction of 20%; see the discussion in set 1 for meat). Milk is replaced by coffee or tea and cheese is replaced by jam.

Table 12.2 shows that a substantial change has to be made to obtain a 10 percent emission reduction. To obtain this reduction meat consumption is nearly halved and in winter season vegetables in the menu include only onions, carrots and cabbage. This is in contrast with the analysis at the start of this paragraph that indicated that refraining from eating meat and drinking milk would result in a 50% decline of the emissions. The difference can be explained by the fact that just refraining is not possible, replacements are needed to fulfill the needs for food and these replacements also require emissions.

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