For example, in case of the dairy sector, it has been estimated that the distribution of dairy products to retailers requires much more energy than does the transport of the milk from farm to dairy. In the farming phase transport play a role due to the movement of animal feed and livestock, although a larger component in the overall impact of this life cycle stage
seems to be the use of nitrogen based fertilizers and pesticides in the production of the cereals which generally constitute animal feed. Cows burping methane are also indicated as source of environmental problems, so, due to general assessment of problem, about 73 percent of the carbon footprint comes from dairy farming (Fig. 1) [Anonymous 2012b].
The reduction of fuel consumption of transport modes used along all food chain stages is one of critical factor influencing
product carbon footprint. In respect to fuel type specific carbon dioxide emissions vary from 2.3 kg to 3,3 kg CO2 per 1 kg of coal and gasoline, respectively [Engineering TollBox, 2012]. Fossil fuels are virtually nonrenewable natural resources. Differences in fossil fuel requirements for vegetable protein and meat protein production strongly depend on the
intensity of agriculture. Depending on the relative intensities of agricultural practices and attributing all energy inputs to the production of foodstuffs, the efficiency of fossil fuel use may be a factor 2.5-50 better for vegetable proteins, if compared with animal husbandry. In European countries, this difference will usually be a factor 6-20 to the advantage of soybean-based protein food [Reijnders and Soret 2003] .
Within the developed world there are four basic transport modes for shipping large quantities of packaged products: water, rail, truck, and air. Although certain food supply chain systems require bulk transport, such as rail, barge or in water, truck transportation dominates most logistic systems, especially toward the consumer end of the chains.
Particularly for perishable foods, trucking remains cheapest and flexible mode of food transport [Ackerly et al. 2010]. To compare transport modes with regard to energy usage and resultant emissions, a ton-km as the movement of 1 metric ton of cargo over 1 km was proposed by Wakeland et al. 2012. Table 2 shows that these modes have very different
energy and emissions profiles
Fig. 1. The relative percentage of carbon footprint in raw milk production
Rys. 1. Względny udział procentowy etapów produkcji mleka surowego w tworzeniu śladu węglowego
Table 2. Energy and emissions per ton-km in dependence of transport mode
Tabela 2. Energia i emisje w przeliczeniu na tonokilometry w zależności od środka transportu
Follow data reported by Ackerly et al. 2010 again in the United States, about 80 percent of all food shipments and 91 percent of all temperature-controlled freight shipments, including about 28.5 million tons of refrigerated fruit and vegetables are transported by truck. Short sea shipping, using ocean-going vessels for delivering cargo domestically, is popular in Europe and also holds promise for replacing many truck deliveries in the United States.
When it comes again to typical "farm-to-fork" food chain, enviromental impacts of transportation in respect to processing phase should be taken into consideration, too. From discussion paper of Massari, 2003 it emerged that European and Japanese companies had much higher levels of production efficiency than their Us counterparts. A reason for this could be that Europe and Japan both have more developed environmental management systems and , in consequence, reduce energy costs, waste disposal and treatment charges. Within the plant, key contributors to energy/carbon use include processing equipment, such as ovens, dehydrators, retorts and pasteurizers; coolers and freezers; compressed air systems; air-handling systems for clean rooms; and lighting. The processor may need to replace certain pieces of equipment to improve energy efficiency. An example would be switching some transportation volume to less CO2-
intensive modes or replacing motors with new ones that are more energy efficient and sized properly to the equipment they power. Internal transport optimization and better control systems can help reduce energy demand and thus the carbon footprint [Connolly 2012].
Transportation is an important factor, both during the retail and food distribution phases and in the process of household consumption. It has been calculated [Massari 2003] that the energy spent by household transport f. e. in the Netherlands, for shopping and eating out (assuming an average 3.5 km journey by car, once a week, for food shopping) amounts to
1280 MJ annually. The energy spent in car use for eating out has been estimated at 20 MJ per outside meal. According to DEFRA report [Forester et al. 2006], the environmental impact of car based shopping are greater than those of transport within the distribution system itself. The environmental impact of aviation is important for air-freighted products, but such product are a small proportion of food consumed. Transportation is, however, only one of the components in the overall consumption phase, which also includes conservation, preparation and final use, each one having its own direct
environmental impact [Massari 2003].
To measure the full impact of a product, we measure greenhouse gas emissions across its
Table 3. Comparison of CO2
-Emissions for various food products (in g CO2e per kg food)
Tabela 3. Porównanie emisji CO2
dla różnych produktów spożywczych (w g ekwiwalentu CO2
na kg produktu)
Based on the above data some "green oriented" organizations postulate to eat only environmental friendly and "climate change friendly" food products. The growing number of publications explores the environmental burden or carbon footprint of diet and the implications of dietary recommendations for the environment [Eshel and Martin 2006, Marlow et al. 2009,]. Leading food retailers on the market footprinted own brand food full life-cycle, from "farm-to-fork". This includes emissions from the extraction of raw materials, direct gas emissions during the agricultural and processing stages, waste
outputs, use of packaging materials, fuel consumption in distribution, energy consumption in processing, retail and product
use by customers, and disposal at end-of-life. Adding these together all of the greenhouse gas emissions gives the total carbon footprint for a product. These data are used sometimes to compare plant and animal origin products in respect to its share in the total CO2 emission. The amount of greenhouse gases caused by the production of food differs very much from one food type to the other (Table 3) [Anonymous 2011].
products across the store to provide advice to suppliers on how they can become more resource efficient, and to advise customers on how they can reduce their household carbon footprint and save money on energy use at home. For example, in a typical 420g can of Tesco's baked beans, the energy used to cook the beans during manufacture contributes 30g
CO2e, and a further 120g CO2e comes from the energy and raw materials used to make the tin can [Anonymous 2012b]. Methodological issues aside, Figure 2 illustrates and summarizes well this approach as a draft categorization of food products according to their carbon footprint. On top of the pyramid, beef and dairy products are some examples of
carbon intensive food products, pork and fish are less intensive, while vegetables belong to the lowest category in terms of GHG emissions [Bakas 2010]. Motivations of purchasing local, organic foods, calculating food miles for individual foodstuffs and choosing food categories with reduced carbon footprint should be issues for discussion in separate elaboration.
Fig. 2. Food products groups in Carbon Footprint (CF) pyramid
Rys. 2. Grupy produktów spożywczych w piramidzie śladu węglowego
CONCLUSIONS
In summary, it is demonstrated in this work that the greenhouse gas emissions associated food transport along whole food supply chain. Carbon Footprint is an issue which is continuing to grow in importance and can be used to study various environmental impacts on each chain stage including primary production, food processing, fuel and energy consumption in food distribution, retail issues and product use by consumer during household consumption. Carbon footprinting method
enables to calculate global impact of foodstuffs and, in consequence, can affect significantly on food choice and purchasing decisions of consumer