Despilfarro de alimentos en el mundo: causas e impacto en los recursos naturales

    FAO estimates that each year, approximately one-third of all food produced for human consumption in the world is lost or wasted. This food wastage represents a missed opportunity to improve global food security and the use of resources from food chains, but also to mitigate environmental impacts. Although it is widely recognized that food production has major environmental consequences, the impacts of food wastage has not yet been analysed from an environmental perspective.

    This FAO report provides a global account of the environmental footprint of food wastage (i.e. both food loss and food waste) along the food supply chain, focusing on impacts on climate, water, land and biodiversity.

    How is food wastage estimated and how much food is wasted?

      The scope of this study is global, it covers all regions of the world and a wide range of agricultural products – representing eight major food commodity groups. Impact of food wastage has been assessed along the complete supply chain, from the field to the end-of-life of food.

      The global volume of food wastage is estimated to be 1.6 Gtonnes of “primary product equivalent”, while the total wastage for the edible part of food is 1.3 Gtonnes. This amount can be weighed against total agricultural production (for food and non-food uses), which is about 6 Gtonnes.

      A model has been developed to answer two key questions:

      1. What is the magnitude of the impacts of food wastage on the environment?
      2. What are the main sources of these impacts, so as to identify “environmental hotspots” of food wastage in terms of regions, commodities, and phases in the food supply?

      Where and how food wastage occurs mostly?

        On average, food wastage is balanced along the whole food supply chain. Agricultural production, at 33 percent, is responsible for the greatest amount of total food wastage volumes. Upstream wastage volumes, including production, post-harvest handling and storage, represent 54 percent of total wastage, while downstream wastage volumes, including processing, distribution and consumption, is 46 percent.

        Wastage occurring at consumption level is much more variable, with wastage in middle and high-income regions at 31–39 percent, but much lower in low-income regions, at 4–16 percent. Vegetables in the Industrialized Asia region (comprised of Japan, China, and South Korea) are a key wastage hotspot. This is mostly due to wastage occurring during agricultural production, post-harvest handling and storage, and consumption phases. Although food wastage percentages at each of these phases are actually lower than in other high-income regions, the high contribution attributed to that region is because it dominates world vegetables production and consumption, with more than 50 percent of both.

        What is the impact of food wastage on greenhouse gas emission and climate?

          Without accounting for greenhouse gas (GHG) emissions from land use change, the carbon footprint of food produced and not eaten is estimated to 3.3 Gtonnes of CO2-equivalent.

          Contribution of each commodity to food wastage and carbon
          Contribution of each commodity to food wastage and carbon footprint

          Contribution of each region to food wastage and carbon
          Contribution of each region to food wastage and carbon footprint

          What is the water footprint related to food wastage?

            The major contributors to the consumption of surface and groundwater resources (i.e. the blue water footprint) of food wastage are cereals (52 % of total) and fruits (18 %). The average water footprint per tonne of primary crop differs significantly among crops. Crops with a high yield or that have a larger fraction of their biomass harvested generally have a smaller water footprint per tonne (e.g. starchy roots, fruits or vegetables) than crops with a low yield or small fraction of crop biomass harvested (e.g. cereals, oilcrops).

            Animal products have, in general, a larger water footprint per tonne of product than crops. This is one of the reasons why from a freshwater resource perspective, it appears more efficient to obtain calories, protein and lipids through crop products than animal products. Also, the feed conversion efficiency, that is the ratio between the amount of feed required and the amount of animal product that is produced, strongly affects the water footprint.

            Globally, the blue water footprint of food wastage is about 250 cubic km, which is equivalent to the annual water discharge of the Volga river, 3.6 times the blue water consumption of the USA for the same period , or three times the volume of Lake of Geneva.

            Regional blue water footprint is much higher in the arid regions of North Africa, West Asia & Central Asia and in South & South East Asia than in other regions. In these two regions, a large share of the footprint is due to cereals which account for about 50 and 60 %, respectively. The average is about 38 m³ per capita and per year and about 30 m³ when not taking animal products into account, to be compared to a blue water footprint for household water consumption of about 7 m³ per capita and per year with the highest value for Canada at 29 m³ per capita and per year. Industrialized Asia and South & South East Asia regions raise concerns, as they also significantly contribute to water scarcity through food wastage.

            What is the impact of food wastage on land use?

              At world level, almost 1.4 billion hectares of land were used for the production of the total amount of food that was wasted in 2007. This represents about 30 % of the world’s agricultural land area, and is larger than the surface of Canada. Low-income regions account for about two-thirds of the total land occupation equivalent, while their contribution to total food wastage is about 50 percent. The major contributors to the surface of land used in the production of food that is wasted are meat and dairy products, which account for 78 % of the total surface, although they represent only 11% of the amount of food wasted.

              Land degradation is also an important factor of food wastage. Almost 99 percent of food wastage at the agricultural production stage appears to be produced in regions where there is also significant land degradation, thus adding undue pressure on the land. In addition, more than half of food wastage at the agricultural production stage is from regions where soil is already degraded.

              What is the impact of food wastage on biodiversity?

                6.1. Regarding terrestrial biodiversity, agriculture is responsible for 66 % of threats to species, but there is considerable regional variability, the greatest threats posed by crop expansion are likely to occur in the tropics, which support the highest species richness and endemism, while providing the greatest scope for increasing global agricultural production. Cereals, which are a main food product that is wasted in most regions, probably constitutes also the main threat to deforestation and biodiversity. Indeed, the production of food crops has approximately twice as much impact on mammals, birds and amphibian biodiversity than livestock production.

                In the developed world, there is generally poor conservation of biodiversity because industrial agriculture and urban expansion have led to declines in farmland diversity, ecosystems’ pollution and habitat loss. On average, crops are responsible for 44 % of threats to species in developed countries, compared with 72 % in developing countries. Bird species appear especially vulnerable to food production activities in tropical and sub-tropical regions, probably because of the relatively high number of forest-dependent species in this group. Fruits and vegetables production is likely to have relatively less important impacts on biodiversity than cereal production because these are usually grown on smaller scales and involve a diversity of crop types, which may contribute to maintaining a certain habitat diversity.

                Current trends towards agricultural land abandonment may lead to further biodiversity declines through reductions in habitat heterogeneity. While it is difficult to estimate impacts on biodiversity at a global level, food wastage and associated externalities increase the problems and biodiversity loss caused by agriculture expansion into wild areas. Most of the impacts of food production on biodiversity occur in low-income regions, such as Sub-Saharan Africa and Latin America. Deforestation due to agricultural expansion and production of food commodities, which is another cause of biodiversity decline, seems to occur today mainly in tropical and sub-tropical areas of the African continent, Western and Southeastern Asia and Southern America. Bioenergy crops, which have witnessed a rapid expansion over the past 10 years, especially in the tropics, do not have so far a major role in deforestation.

                6.2. Regarding marine biodiversity, countries are “fishing down the food chain,” with fish catches increasingly consisting of smaller fishes that are lower in the food chain. The average mean trophic level has been declining in most large marine ecosystems since 1950, but this decline occurs at very different rates in different seas and regions. Middle- and high-income regions which have a diversity of seas (i.e. Europe, North America & Oceania, Industrialized Asia) have approximately two thirds of their seas showing declining trends in the mean trophic level of catches since 1950. This is likely due to the importance of commercial fishing and its impacts on the food webs. In contrast, developing regions with few seas show relatively stable or positive trends since 1950 probably reflecting the fact that fishing mostly occurs at artisanal or subsistence levels in these areas.

                What is the economic impact of food wastage?

                  On a global scale, about USD 750 billion worth of food was wasted in 2007, the equivalent of the GDP of Turkey or Switzerland, and this value is a low estimate since it mainly considers producer prices and not the value of the end product.

                  Vegetables are the major contributors to the economic cost of food lost and wasted (23% of total cost), followed by meat (21 %), fruits (19 %) and cereals (18 %). Meat’s contribution to the total cost of food wastage is clearly driven by its high producer cost per kilogram. The major contributors are Ind. Asia (31 percent of total) and S&SE Asia (18 percent), the two regions that are also the largest contributors to food wastage volumes.


                    The Table below presents a cross-analysis of all quantifiable environmental components. All the “region*commodity” pairs that appeared in the top 10 for carbon, blue water or land occupation (arable or non-arable) are presented here with their contribution to total food wastage.

                    Table 3: Cross-analysis of all environmental components, by
										“Region*Commodity” pairs. In each column: contribution to
										total in percent and ranking from 1 to 10 (or 5) in
                    Table 3: Cross-analysis of all environmental components, by “Region*Commodity” pairs. In each column: contribution to total in percent and ranking from 1 to 10 (or 5) in bold

                    It appears globally that:

                    • Cereal wastage in Asia emerges as a significant environmental hotspot, with major impacts on carbon, blue water and arable land;
                    • Meat has high impacts in terms of land occupation and carbon footprint, making it a major environmental hotspot, although wastage volumes in all regions are relatively low
                    • Fruit wastage emerges as a blue water hotspot in Asia, Latin America and Europe, but it is linked more to food wastage volumes than to the blue water intensity of the commodity;
                    • The carbon footprint of vegetables singles them out as a hotspot in Industrial Asia, Europe, and South & South East Asia, mainly due to large food wastage volumes with a higher wastage in Europe, due to the fact that a higher share of vegetables is grown in heated greenhouses;
                    • Starchy roots, although experiencing high volumes of wastage in Sub-Saharan Africa, Europe and Industrialized Asia, never appear in impacts top 10. This commodity actually has low carbon, water and land intensity, mostly because yields are high, thus limiting the impacts per kg.

                    What are the main improvement areas that could be made in food wastage assessments ?

                      Four main areas are identified:

                      1. A database consolidating worldwide statistics on food wastage would provide harmonized datasets for analysis and the prerequisite for developing such a global tool is to have harmonized definitions of the major concepts linked to food loss and waste;
                      2. Due to a lack of data or other methodological constraints, a number of assumptions had to be made to quantify environmental impacts;
                      3. Further research would be needed to clarify the biodiversity impacts of food throughout the supply chain, including trade issues;
                      4. Further research to quantify the costs along the food supply chain is needed. In addition, the environmental cost of lost natural resources due to food wastage could be taken into account in future work.

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