Greenhouse gas emissions from the consumer side

The production side data were obtained from environmental statistics. Estimation of emissions related to consumption requires quite different methodologies. Life cycle analysis (LCA) methodologies (Rebitzer et al., 2004) are the most suitable tools. Initially LCA was developed to assess the environmental impacts of industrial processes; recently the method is also applied to agriculture (Audsley et al., 1997). It determines the environmental impacts of a product from cradle to grave, accounting for all the processes involved in manufacturing, transport and consumption of the product, this includes the extraction of the raw materials to possible waste treatments. Conducting an LCA involves a lot of information and a lot of work. To give an example: to calculate the environmental impacts associated with consumption of a litre of milk it is necessary to determine all the impacts required to get a litre of milk on the table of the consumer. This includes consideration of the impacts of farming practices; producing the fertilizers used on the farm; cooling, processing, packaging and transporting the milk from the farm via the dairy factory and the supermarket to the consumer; along with the waste treatments required to discard the packages.

In principle, when the environmental impact of all consumer goods is known the environmental impact of the total consumption can be determined by multiplying the environmental impact per unit of the product by the number of units of the product purchased.

The large amount of work involved in such an analysis makes it practical for only a limited number of products. This implies that there is no overview for the total environmental impact of the total consumption bundle. Only an energy based LCA exists with respect to the total consumption bundle. Namely, Kok et al. (2001) analyzed the energy requirements of over 350 products and services (including food, music lessons, bicycles, clothing etc.) starting with the energy required to extract the raw materials to the energy involved in the waste treatments. Figure 12.4 shows some of their results. Half of the energy attributed to households concerns heating, electricity, and transport (petrol for the car) and the other half has to do with product consumption and accounts for energy that was used elsewhere in society. In this 'consumption half' food is a major player.

CO2 emission related to consumption food food

petrol remainder

Figure 12.4 Distribution of the CO2 emissions related to consumption over the different spending categories Source: Vringer and Blok (2000).

petrol remainder

Figure 12.4 Distribution of the CO2 emissions related to consumption over the different spending categories Source: Vringer and Blok (2000).

This large contribution of food to total energy requirements is quite in contrast to what is found in the production perspective (where agriculture only accounted for 5% of the national energy use). This is because energy used in other sectors than agriculture is substantially used in association with consumed food. In a consumer oriented approach the energy used for transporting food is attributed to food, while in a production-oriented approach it is attributed to the transport sector. A comparable situation exists for the industrial sector. In a consumer oriented approach, the energy used in the food industry is attributed to food as is the energy used in the fertilizer industry.

With respect to food a detailed study exists in which CO2, CH4 and N2O related to over 150 food items were examined (Kramer, 2000). In that study, greenhouse gas emissions along the complete production chain were analyzed and those results will be discussed in detail.

The 150 food commodities are grouped into categories. 'Bread' aggregates products where grains (wheat, rice, maize) are the major ingredients like breads, cakes and pastry, but also pastas. 'Potatoes' represents potatoes and vegetables and fruits, 'Beverages' aggregates beer, coffee, tea, fruit juices, but also confectioneries. The category 'Meat' concerns all meat and fish products, 'Dairy' includes milk, yogurt, butter and cheese, the 'Oil' category involves vegetable oils and fats to fry, 'Remainder' includes spices and ready to eat meals.

Figure 12.5 shows the emissions related to these different categories. One should realize that emissions related to consumption depend on both emissions per unit and the amount consumed. The emissions related to an exotic fruit can be very high, but when the volume consumed is small then the contribution to national emissions is low. This also holds the other way round: the emissions of for instance a unit of milk may be low, but since it is consumed in very large quantities the overall impact can be high.

CO2 emissions related to food consumption

CO2 emissions related to food consumption


N2O emissions related to food consumption

N2O emissions related to food consumption

Figure 12.5 Distribution CO2, CH4 and N2O emissions and CO2-equivalents over various food product categories in the Dutch food consumption package Source: Kramer (2000).

methane emissiois related to food consumpfon

- bread methane emissiois related to food consumpfon

- bread

C02 equL related to food consunptbn bread bread

Figure 12.5 Continued

The emissions are not distributed evenly over the categories and gasses. With respect to CO2, bread, beverages, meat and dairy provide the largest contribution (80%). With respect to CH4, meat and dairy are responsible for 80% of the emissions. For N2O the largest share arises from dairy, bread, beverages, and potatoes. For all greenhouse gasses, dairy consumption plays the largest role. More detailed analysis of the emissions attributed to dairy shows that the CO2 emissions arise from chemical fertilizer production (this fertilizer is used to fertilize grasslands), production of livestock feed (a large part is from imported soybeans, which are transported over large distances) and in milking, cooling, transporting and packaging. The CH4 emissions attributed to milk are mainly due to the CH4 emitted by the cows in enteric fermentation. The N2O emissions occur during the production of chemical fertilizer and as a result of de-nitrification processes in grasslands. So different parts of the production chain are responsible for the emissions.

This also accounts for the other commodities including food packaging. With respect to CO2 20% of the emissions occur as part of primary production, and the remaining 80% arise outside the agricultural production system, either through delivery of inputs, processing and transport of food, retailing or in the households (cooling and cooking). The emissions of N2O and CH4 show a different picture with 80% of these emissions occurring in association with primary production.

The differences in environmental impact of the various consumption items imply that there are options to change emissions under alterations in consumption patterns. From Figure 12.5 it is apparent that for CH4 the consumption of milk, cheese and meat is of importance. For N2O the emissions are spread more evenly over the consumption items (all agricultural production requires chemical fertilizer), but dairy holds the largest share. Refraining from milk and meat, for instance, would result in a 75% reduction of CH4 emissions, related to food consumption, for N2O refraining from milk and meat results in a reduction of about 40%.

Another option to reduce the environmental impact from consumption is the purchase of products which are produced using processes with lower environmental impacts much like those discussed in the production side analysis. However, a change in production techniques from the consumer point of view may involve other changes. To give an example: the use of vegetables grown in heated greenhouses involves large amounts of energy. Improvement of the production techniques from the producer side would include the use of better-insulated greenhouses. From a consumer perspective a switch to vegetables grown in the open air is also an option. A comparable situation exists for transport: from a producer perspective reduction in energy use in transport can be obtained from more efficient trucks. From a consumer perspective less transport is also an option (increasing consumption of locally grown products).

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