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The Ecological Footprint of Cassava and Maize Post-Harvest-Losses in Nigeria A Life Cycle Assessment
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Contents
List of Figures 3List of Tables 4Acronyms 4
1 Executive Summary 5
2 Introduction 6
3 Goal of the Study 8
4 Scope of the Study 9
4.1 Definition of food losses 9 4.2 System description 9 4.2.1 Agricultural Production 9 4.2.2 Transport and Distribution 10 4.2.3 Processing 10 Cassava Processing/ Gari Production 10 Cassava Starch Processing 10 Processing of maize into feed 10 4.2.4 Different steps of losses 11 4.3 System Boundaries 11 4.4 Function and Functional Unit 12 4.4.1 Function 12 4.4.2 Functional Unit 12 4.5 Selection of Impact Assessment Categories 12 4.5.1 Main indicators 12 4.5.2 Impacts not considered in a quantitative way 13 4.6 Data Collection And Treatment 13 4.7 Co-product Allocation 14 4.8 Overall Data Quality, Representativeness and limitations 14 4.9 Software and Database 14
5 RESULTS 15 5.1 Environmental Impact of Final Product 15 5.1.1 Gari 15 5.1.2 Cassava Starch 18 5.1.3 Maize feed flour 21 5.2 Environmental Impact of Total Losses 23 5.2.1 Impacts of the Cassava value chain 23 5.2.2 Impacts of the maize value chain 27 5.3 Qualitative assessment of impact on biodiversity 31 5.3.1 Biodiversity in the food supply chain 31 5.3.2 Impact of food production on biodiversity within a LCA 31 5.3.3 Land use Change as indicator for impact on biodiversity 31 5.3.4 Conclusion – impact on biodiversity 32
CONTENTS
3CONTENTS
6 Environmental Footprint of Food Losses in Nigeria – Setting them into Perspective 34
7 Options for Mitigation 36
8 Conclusion 37
9 References 38
Appendix A: Description of Impact Categories 39
Appendix B: Assessing the impact of food production on biodiversity within a LCA 42
Appendix C: Scenario analysis – Manual Processing 44
Appendix D: Data Base of Calculation 45
List of Figures Figure 1: Principles of the Life Cycle Assessment Scheme 7Figure 2: Contribution of different life cycle phases to carbon footprint of 1t Gari 15Figure 3: Contribution of different life cycle phases to carbon footprint of 1t Gari 16Figure 4: Contribution of different life cycle phases to total freshwater use of 1t Gari 16Figure 5: Contribution of different life cycle phases to water deprivation (WSI) of 1t Gari 17Figure 6: Contribution of different life cycle phases to land use (occupation) of 1t Gari 18Figure 7: Contribution of different life cycle phases to carbon footprint of 1t Starch 18Figure 8: Contribution of different life cycle phases to carbon footprint of 1t Starch 19Figure 9: Contribution of different life cycle phases to total freshwater use of 1t Starch 19Figure 10: Contribution of different life cycle phases to water deprivation (WSI) of 1t Starch 20Figure 11: Contribution of different life cycle phases to land use (occupation) of 1t Starch 20Figure 12: Contribution of different life cycle phases to carbon footprint of 1t Maize feed 21Figure 13: Contribution of different life cycle phases to carbon footprint of 1t Maize feed 21Figure 14: Contribution of different life cycle phases to total freshwater use of 1t maize feed 22Figure 15: Contribution of different life cycle phases to water deprivation (WSI) of 1t Maize feed 22Figure 16: Contribution of different life cycle phases to land use (occupation) of 1t Maize feed 23Figure 17: Carbon footprint of PHL of Cassava 25Figure 18: Total freshwater use of PHL of Cassava 26Figure 19: Water deprivation (WSI) of PHL of Cassava 26Figure 20: Land use (Occupation) of PHL of Cassava 27Figure 21: Carbon footprint of PHL of Maize 29Figure 22: Total freshwater use of PHL of Maize 30Figure 23: Water deprivation (WSI) of PHL of Maize 30Figure 24: Land use (Occupation) of PHL of Maize 30Figure 25: Area development of forest, cassava production and maize production in Nigeria (1990 and 2009) 32Figure 26: Top Ten crop production in Nigeria in 1990 (left) and 2010 (right). 33Figure 27: Greenhouse effect 39Figure 28: Manual labour scenario – cassava 44Figure 29: Manual labour scenario – maize feed 44
4 CONTENTS
List of tablesTable 1: Losses occurring within the supply chain of selected Cassava and Maize products 11Table 2: System boundary – inclusions and exclusions 12Table 3: Life cycle impact assessment categories & indicators 13Table 4: Data sources overview 14Table 5: Quantities lost along the cassava value chain, impact of the product and total impact of losses 24Table 6: Summary of environmental impact of cassava PHL 25Table 7: Quantities lost along the maize value chain, impact of the product and total impact of losses 28Table 8: Summary of environmental impact of maize PHL 29Table 9: Production quantities and losses in the cassava value chain 45Table 10: Production quantities and losses in the maize value chain 46 ACRONYMS
APHLIS African Postharvest Losses Information SystemCF Carbon footprintEoL End of LifeFSC food supply chainsFU functional unitGaBi 5 Software system for life cycle engineering, developed by PE INTERNATIONALGHG Greenhouse gasesGIZ Deutsche Gesellschaft für Internationale Zusammenarbeit GmbHGWP Global warming potentialLCA Life Cycle AssessmentLCI Life Cycle InventoryLCIA Life Cycle Impact AssessmentPHL Post-Harvest LossesWSI Water stress index
5ExECuTivE Summary
1 Executive Summary
The issue of food losses is of high importance in the ef-forts to combat hunger, raise income and improve food security in the world’s poorest countries. However, food losses also represent a waste of resources used in produc-tion such as land, water, energy and inputs. These addi-tional environmental impacts of food losses are the focus of this study.
Life cycle assessment (LCa) is a standardized scientific method for systematic analysis to assess environmental impacts. On behalf of GiZ, PE iNTErNaTiONaL con-ducts a Life Cycle assessment (LCa) in accordance with iSO 14040/44 (iSO 2006) for environmental impacts of food losses in the two staple crops maize and cassava production in Nigeria. The product system under study covers process steps from cultivation to distribution: cultivation, post-harvest losses, transport to market, pro-cessing to final product, and transport to point of retail (cradle-to-shelf approach). it has to be stated that not all possible processing and distribution ways of cassava and maize could be covered because of missing data. This is why this study does not claim to cover the full value chain of cassava and maize in Nigeria, but rather a rel-evant fraction of it.
The study is based on primary data from a previous study for the GiZ on food losses in Nigeria (OGuNTaDE 2013), supplemented with literature and data from PE iNTEr-NaTiONaL’s GaBi5 data base. The study includes the fol-lowing environmental impact categories: global warming potential, water footprint and land occupation. impacts on biodiversity are assessed in a qualitative way.
On a product basis, the cassava products 1t Gari has a global warming potential of 0.58t CO2eq., 1t of starch 0.7t CO2eq. and 1t of maize feed 0.73 t CO2eq. agriculture is
the main contributor to the global warming potential of all products. Processing contributes around one third to the impacts for cassava products and only 10% to the impact of maize. With regard to water, the assessment shows that only a minor fraction of the total freshwater use is relevant for environmental depletion, assessed as water deprivation. a water deprivation of 0.3m³ is caused by producing 1t of Gari, about the same amount for 1t of maize. For cassava starch the amount is larger with a water deprivation of 18m³. The main driver behind blue water use is the flushing out of starch from the tubers.
Looking at the environmental footprint summed up over the complete value chain, it can be seen that the food losses investigated in this study indeed have a large envi-ronmental footprint. The cassava and maize value chain together contribute around 2.3 million tonnes of CO2e to the atmosphere and to a water deprivation of 2.8 million m³. Land occupation due to losses in sum accounts for 1.7 million ha. That means that land occupation through losses accounts for 21% of the area cultivated with maize and cassava. The impact assessment of production sys-tems with regard to biodiversity is difficult to quantify. it can be stated nevertheless that a direct linkage can be made from each impact category assessed in this report to biodiversity. Considering biodiversity can therefore only strengthen the concerns on preventable environ-mental burden caused by food losses.
it has to be stated that loss rates and emission factors presented in this study are more likely to be seen on the worst case side of the possible impact scale. Data un-certainty regarding production quantities and reported losses remain. However, the results are a clear indicator that food losses cause a significant impact on the envi-ronment.
6 iNTrODuCTiON
2 Introduction
The issue of food losses is of high importance in the ef-forts to combat hunger, raise income and improve food security in the world’s poorest countries. Food losses have an impact on food security for poor people, on food quality and safety, on economic development and on the environment. The loss of nutritional and economic value of food waste has been core to the food wastage debate so far. However, food losses also represent a waste of resources used in production such as land, water, energy and inputs. These additional environmental impacts of food losses are the focus of this study.
On behalf of the German Federal ministry for Economic Cooperation and Development (BmZ), Deutsche Gesellschaft für internationale Zusammenarbeit (GiZ) GmbH has been studying impact and possible preven-tion of food losses already for a long time. Preceding this study, GiZ has conducted an investigation of food losses along the value chain of cassava and maize in Nigeria (OGuNTaDE 2012). The main aim of this study was to quantify food losses and their economic value in impor-tant food value chains in Nigeria. Cassava and maize were chosen because they constitute the main staple food of people living in rural areas as well as the fast growing cities of Nigeria. Further, options for German develop-ment cooperation to engage in programs for food losses reduction were identified.
as outlined above, an important aspect of food losses is the “wasted” environmental burden they bring with them. Building on data and results of OGuNTaDE 2012, this study continues the investigation by supplementing information of the carbon footprint, water footprint, im-pacts on biodiversity and land occupation caused by food losses in Nigeria.
Life cycle assessment (LCa) is a standardized scientific method for systematic analysis of flows (e.g. mass and energy) associated with the life cycle of a specific prod-uct, technology, service or manufacturing process system to assess environmental impacts. The environmental impacts of food losses in Nigeria have been assessed fol-lowing the iSO 14040/44 standards for environmental impact assessment.
according to these standards an LCa study consists of four phases (iSO 2006):
1. Goal and scope definition (framework and objective of the study);
2. Life cycle inventory (input/output analysis of mass and energy flows);
3. Life cycle impact assessment (evaluation of environmental relevance, e.g. global warming potential); and
4. interpretation (e.g. optimization potential)
7iNTrODuCTiON
being studied. The LCi data can be used to understand total emissions, wastes and resource-use associated with the material or the product being studied; improve pro-duction or product performance; or be further analysed and interpreted to provide insights into the potential en-vironmental impacts from the system (life cycle impact assessment and interpretation, LCia).
This structure of an LCa as outlined in the standards will be found in the following chapters.
The goal and scope stage outlines the rationale of the study, the anticipated use of the results of the study, the boundary conditions, the data requirements and the assumptions to analyse the product system under consideration, and other similar technical specifica-tions for the study. The life cycle inventory (LCi) stage qualitatively and quantitatively analyses the materials and energy used (inputs) as well as the products and by-products generated, the environmental releases in terms of emissions to the environmental compartments and the wastes to be treated (outputs) for the product system
Figure 1: Principles of the Life Cycle Assessment Scheme
8 GOaL OF THE STuDy
3 Goal of the Study
On behalf of GiZ, PE conducts a Life Cycle assessment (LCa) in accordance with iSO 14040/44 (iSO 2006) for environmental impacts of food losses in maize and cas-sava production in Nigeria. The main goal of the study is to analyse the cradle-to-shelf (i.e. production, transport, processing, and distribution) environmental perfor-mance of food loss in the value chain of maize and cassa-va and provide credible scientific evidence for informed decision making in areas related to the environmental impact of Nigerian maize and cassava production. Exist-ing projects and initiatives (FaO, african Postharvest Losses information System aPHLiS) state, that data on post-harvest losses (PHL) are unreliable and that fur-ther research is needed. For this reason, the goal of this study is twofold: First, to illustrate the environmental dimension of food losses from production until retailer in terms of wasted natural resources and unnecessary greenhouse gas emissions. Second goal is to improve the data availability regarding food losses in important food value chains in africa, to be able to identify options for German development corporations to engage in pro-grams fostering the reduction of food losses and their environmental impacts.
Therefore GiZ is interested in:
• Data collection and compilation of existing informa-tion on food production chains of cassava and maize in order to set up a life cycle inventory
• Calculation of the impacts of the food losses under study on global warming potential, water availability, land occupation and biodiversity
• refinement of the contribution of particular life cycle steps on the defined impact categories
• Test of impacts of potential behaviour changes or tech-nology changes
• Discover potential future food supply efficiency im-provements
The intended audience of this study are members of GiZ and their consultants, experts in the agricultural sector (especially those dealing with PHL), policy makers in Nigeria, and LCa practitioners.
9SCOPE OF THE STuDy
4 Scope of the Study
The following section describes the general scope of the project that has been set to achieve the stated goals. This includes the identification of specific products to be assessed, the supporting product systems, and the boundary of the study, the allocation procedures, and the cut-off criteria.
4.1 Definition of food losses
Food losses refer to the decrease in edible food mass throughout the part of the supply chain that specifically leads to edible food for human consumption. Food losses take place at production, postharvest and processing stages in the food supply chain (FaO 2011).
Food losses occurring at the end of the food chain (retail and final consumption) are rather called “food waste”, which relates to retailers’ and consumers’ behaviour (FaO 2011). Food waste is thus not covered in this study.
Five system boundaries were distinguished in the food supply chains (FSC) of vegetable and animal commodi-ties by FaO 2011:
1. agricultural production: losses due to mechanical damage and/or spillage during harvest operation, crops sorted out after harvest, etc.
2. Postharvest handling and storage: including losses due to spillage and degradation during handling, storage and transportation between farm and distribution.
3. Processing: including losses due to spillage and deg-radation during industrial or domestic processing, e.g. juice production, canning and bread baking. Losses may occur when crops are sorted out if not suitable to process or during washing, peeling, slicing and boiling or during process interruptions and accidental spillage.
4. Distribution: including losses and waste in the market system, at e.g. wholesale markets, supermarkets, retail-ers and wet markets.
5. Consumption: including losses and waste during con-sumption at the household level.
in this study, only food losses occurring until end of pro-cessing and retailing of the respective product are con-sidered (cradle-to-shelf approach - phases 1 to 4). Losses on consumer level are difficult to estimate and always subject to high data uncertainty and are therefore not considered in this study. it has to be stated as well that not all possible processing and distribution ways of cas-sava and maize could be covered in the underlying data collection (OGuNTaDE 2012). This is why this study does not claim to cover the full value chain of cassava and maize in Nigeria, but rather a relevant fraction of it.
4.2 System description
Two staple crops in Nigeria are investigated, cassava and maize. Cassava (manihot esculenta), is extensively cultivated as an annual crop in tropical and subtropical regions for its edible starchy, tuberous root. Two process-ing routes are investigated: processing to Gari (a creamy-white, granular flour made from fermented, gelatinized fresh cassava tubers) and processing to starch (made by leaching and drying the root of the cassava plant). maize (Zea mays) refers to both, the whole plant (cultivated for its yellow edible grains, which develop on a cob) and to the grain used for food and feed. in this study only the processing to flour used as feed is considered. For fur-ther information on production quantities, regions and practices, as well as detailed description of the processing please refer to OGuNTaDE 2012.
as stated above, food loss occurs at production, post-harvest and processing stages in the food supply chain. The life cycle stages of maize and cassava are described briefly in the following. For full reference please see OGuNTaDE 2012.
4.2.1 Agricultural ProductionThe “cultivation phase/stage” of the system includes:
• Land preparation (clearing)
• Planting (laying-out, tilling, planting)
• Weeding/farm maintenance
• Harvesting/transportation for off-farm activities
10 SCOPE OF THE STuDy
maize and Cassava are modelled as mixed crop sys-tem (see OGuNTaDE 2012). Typically maize is planted first, the cassava cuttings are later planted on the same heaps when the maize is fully grown on the field. after the maize is harvested, the cassava takes over the field completely. Thus the cost of land preparation and initial weeding is shared between maize and cassava. Economic allocation was applied to allocate burdens between the two products (see also chapter 4.7)
With the exception of chain-saw operators engaged at land preparation and herbicide spraying, all other farm activities are conducted manually.
The environmental analysis of the cultivation was done using an agricultural plant model within the LCa soft-ware GaBi 5. The model is a mixed balance model with different compartments to address specific emissions during cultivation. The following aspects are covered with the agricultural model used for this analysis:
1. Emissions from clearance (burning)
2. Emissions from field operations (land machine use)
3. Emissions from supply of input materials (fertilizer, pesticides)
4. The N-emissions to groundwater, through erosion and as field emissions (as NO3- and NH3, N2O, and N2)
5. Fertiliser compensation through crop rotation (Nitrogen surplus or deficit left to the following crop is accounted for)
4.2.2 Transport and DistributionThe “distribution phase” includes transport and losses during transport and storage. Transportation was mod-elled based on distances given by OGuNTaDE 2012. main transport routes are from farm to market, from market to processing and from processing back to market.
4.2.3 Processingin smallholder enterprises, all operations are done manually. Larger commercial processing centres use ma-chines. in this study mechanical processing was assumed. in the scenario analysis section (appendix B) the reduc-tion in environmental burden due to manual operation is assessed.
Cassava Processing/ Gari ProductionThis stage includes:
• Peeling of the tubers
• Washing the peeled tubers
• Grating into mash
• Fermentation and dewatering (pressing)
• Sieving
• Frying of the sieved particles
Cassava Starch ProcessingThe activities involved in the production of starch are:
• Peeling of the tubers,
• rasping and solution of starch in water
• Sedimentation of starch
• Separation of starch
• Drying
Processing of maize into feedan important fraction (>15%) of the total maize produc-tion in Nigeria is processed to feed. The major processing step at this stage is the milling. The meal is then mixed with other feedstuff to form a ration suitable for its in-tended purpose. The provision of other feedstuff was not within scope of this study and is not modelled.
11SCOPE OF THE STuDy
Elements excluded from the system are the production of capital equipment, human labour and commuting. These elements are traditionally excluded from the prod-uct-LCas as they are assumed to fall far below the cut-off criteria. Table 2 gives examples of the industry activities included and excluded in the assessment. See chapter 4.3 for further details on cut-off criteria and flows excluded.
4.2.4 Different steps of lossesLosses occur all along the value chain. in accordance with OGuNTaDE 2012 different loss-stages are identified: Each loss-stage is successively associated with higher en-vironmental burden, because impacts caused upstream in the value chain are all allocated to the product at the respective stage.
4.3 System Boundaries
The product system under study is a cradle-to-shelf system covering process steps from cultivation to Distri-bution:
• Cultivation
• Post-harvest losses
• Transport to market
• Processing to final product
• Transport to point of retail
Gari losses at: Cassava starch losses at: Maize flour losses at:
Cassava Tuber at farm (1)
Maize cobs at farm gate (1a)
Maize grains at farm gate (1b)
Cassava Tuber Processing (2)
Maize grains during marketing (2)
Gari Processing (3a)
Cassava Starch processing and storage (3b)
Maize grains at feed milling (3)
Gari at Marketing phase (4)
Feed during Marketing (4)
Table 1: Losses occurring within the supply chain of selected Cassava and Maize products
12 SCOPE OF THE STuDy
4.5 Selection of Impact Assessment Categories
This study extensively uses food loss rates as a part of the mass inventory. The food loss rates are also communicat-ed in this report as indicator of inefficiencies. The food losses environmental implications were assessed using the following impact assessment categories:
4.5.1 Main indicatorsa comprehensive set of environmental impact categories has been investigated. The study includes the following inventory flows and environmental categories:
• global warming potential;
• water footprint;
• land occupation;
an overview of the impact categories is given in Table 3. an elaborate description of the impact categories and methodology used can be found in appendix a.
4.4 Function and Functional Unit
4.4.1 FunctionThe products made from cassava (Gari and starch) are widely spread staple food in Nigeria. maize is consumed without further processing as cobs or grains, processed to flour or used as animal feed.
4.4.2 Functional UnitThe functional unit (Fu) quantifies performance/func-tion of a product system for use as a reference unit.
The functional unit and reference flow declared in this report is 1 kg of final product at the shelf. as described above each stage in the value/processing chain of the product under study is associated with an increasing en-vironmental burden, because the impacts of the proceed-ing stages are accumulated. This is why the processing stage has to be taken into account when calculating the associated environmental impact. additionally, in later stages of the value chain, the losses do not occur as raw materials, but as processed product (e.g. Gari), represent-ing a “concentration” of the base material, thus also accu-mulating the environmental impact of its precursors.
For the accumulated results of all losses over the com-plete value chain the functional unit is total amount of losses occurring in the value chain from cradle-to-shelf.
Cradle-to-shelf of cassava and maize products (Gari, Starch, Maize flour)
included examples
Production of raw materials • Production of raw materials
Production of auxiliary materials • Production of auxiliary materials
Energy production • Energy production
Transport • Transport
excluded examples
Construction of capital equipment • Production of processing equipment (e.g. press)
Human labour and employee transport • Production of food for employees
• Employees commuting to work
Use phase and EoL phase
• Food waste at retailer and consumer
• Waste collection at the consumer
• Waste treatment
Table 2: System boundary – inclusions and exclusions
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4.6 Data Collection And Treatment
Primary and secondary data collected were provided in a consistent way to GaBi 5 background data. Table 4 illustrates an overview of the main production steps and the data sources.
4.5.2 Impacts not considered in a quantitative wayThere are environmental impacts for which the evalu-ation methodology is less mature. These impacts are classified with ii and iii in the iLCD handbook (recom-mended, but to be applied with caution, iLCD 2011). Biodiversity is included in that category. Qualitative as-sessment and some inventory results are used to address these impacts in this study (see chapter 5.3).
LCIA categories and indicators used in assessment of environmental footprint of PHL maize and cassava production in Nigeria
Category Indicator
Impact category
Description Unit Reference
Climate Change Global Warming Potential* (GWP)
A measure of greenhouse gas emissions, such as CO2 and methane. These emissions are causing an increase in the absorption of radiation emitted by the earth, magnifying the natural greenhouse effect.
kg CO2
IPCC, 2006,
100 year GWP
is used
Water Water footprint
The water footprint of a system is a set of different calculations and should be used as an umbrella term rather than to communicate a single number. So far, water footprinting focuses on the water lost to the watershed, i.e. water consumption. Water consumption is considered to have a direct impact on the environment (e.g. freshwater depletion and impacts to biodiversity). In the assessment of water consumption it is crucial where the water consumption takes place. This is addressed by ap-plying the water stress index (WSI) developed by Pfister et al (2009). The water stress index is used to weight water consumption according to regio-nal availability, i.e. a multiplication of consumptive water use with the water stress index (WSI).
equivalent
Bayart et al. 2010
ISO 14046 (in progress)
Pfister et al. 2009
Land use (occupation)
As a sub-group of land use (functional dimension of land and area that is used for urban, agricultural, forestry and other purposes) land occupation can be defined as the maintenance of an area in a par-ticular state over a particular time period.
m³ Energy production
*The terminology “potential” is defined by ISO and used to clearly indicate that LCIA shows potential impacts in the future. For example for climate change the Global Warming Potential represents the potential impact of GHG emissions related to the reference unit CO2.
Table 3: Life cycle impact assessment categories & indicators
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4.8 Overall Data Quality, Representativeness and limitations
The study is based on primary data from OGuNTaDE 2012, supplemented with literature values, data from FaO and data from the GaBi 5 databases. Geographic reference is Nigeria. Time representativeness is 2010 to 2012. as stated by FaO 2011, data on post-harvest losses are always subject to high uncertainty. additionally, processing practices differ and reach from family based manual labour to large processing plants. it has to be stated as well that not all possible processing and distri-bution ways of cassava and maize could be covered in the underlying data collection (OGuNTaDE 2012). This is why this study does not claim to present a complete and detailed LCa of the complete value chains under study. it rather has to be seen as screening assessment to identify hotspots and to provide first estimations on the overall environmental impact of cassava and maize food losses.
4.9 Software and Database
The LCa model is created using the GaBi 5 Software system for life cycle engineering, developed by PE iN-TErNaTiONaL. The GaBi database provides the life cycle inventory data for fuels and energy obtained from the background system.
in the following, assumptions that are made during modelling are described.
• Cultivation: the cultivation system was assumed to be a mixed crop system of cassava and maize.
• Transport: diesel driven trucks are used, 3.3t payload capacity with 85% utilization
• Processing: waste water is assumed to be released to the environment without further treatment. Losses are assumed to be either used as animal feed or to be simply discarded as organic waste, so they also they leave the system burden free, no further treatment is assumed. Processing is assumed to be supported by electricity driven machines. manual operation is given as an alternative scenario. Gari frying was assumed to be operated by firewood. Firewood releases only bio-genic CO2 while being burned, supply was assumed to be burden free (collection from the surrounding, waste material, no cultivation).
4.7 Co-product Allocation
Price data for co- products are used for the economic al-location between maize and cassava from the mixed crop system. By-products from the processing (peels, fibre, losses) are used for animal feed, but have little to no value (OGuNTaDE 2012), so they leave the system burden free. Losses are also assumed to be either used as animal feed or to be simply discarded as organic waste, so they also they leave the system burden free.
Sources overview for cradle-to-gate plus transport LCA of maize and cassava produced in Nigeria
data data source
Cultivation Primary data (OGUNTADE 2012), PE agricultural model; GaBi5 background data
Transport Distances from OGUNTADE 2012; GaBi5 background data
Processing Secondary data (FAO, SRINOPHAKUN ET AL. 2000, traders specifications)
Distribution Primary data (OGUNTADE 2012)
Table 4: Data sources overview
15rESuLTS
• Fertilizers: Emissions from fertilizer production.
• Field Emissions: Emissions to groundwater, air and soil from microbial transformation of mineral and organic nitrogen in the soil.
• Field operations (tractor Operations: e.g. sowing, fertilizing, harvesting).
• Pesticides: Emissions from pesticide production.
• Processing: Emissions due to the energy consumption in processing
• Transport: all transport processes (farm, market, processing, market)
5.1.1 Gari Figure 2 shows the GWP of 1t Gari and the contribution of different life cycle phases.
The following section describes the results of the analysis in the respective impact categories. First, the results of 1 t final product (Gari, starch, feed meal) are described and the contributions of different lifecycle phases are shown. afterwards, the aggregated environmental impact of all losses over the value chain is shown.
5.1 Environmental Impact of Final Product
in the contribution analysis different lifecycle phases are distinguished as described in the following:
• Clearance: Emissions occurring through the burning of left biomass from previous planted crop to prepare the seed bed.
• Crop Rotation: Credits or impacts due to nutrient surplus or deficit. Depends on crop specific nutrient efficiency, soil parameters, previous and following crop and management practices.
Figure 2: Contribution of different life cycle phases to carbon footprint of 1t Gari
5 Results
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
1t Gari
t CO
2e/t
final
pro
duct
Transport
Processing
Pesticides
Field operations
Field emissions
Fertilizer
Crop rotation
Clearance
16 rESuLTS
Processing and transport following the farm activities contribute less to the GWP of the final product than the agricultural phase. This fact is further illustrated with Figure 3.
The carbon footprint of 1 t Gari is 0.58t CO2e.1 Largest contributors are the field emissions during cultivation. Other emissions caused by cultivation activities contrib-ute equally to the GWP of the final product: clearance, crop rotation, fertilizer supply and field operations.
Figure 3: Contribution of different life cycle phases to carbon footprint of 1t Gari
Figure 4: Contribution of different life cycle phases to total freshwater use [m³] of 1t Gari
72%
28%
Agriculture
Processing + Transport
0
100
200
300
400
500
600
700
1t Gari
m/t
Upstream supply + Processing
Rain
The next figure (Figure 4) shows the contribution of dif-ferent phases to total fresh water use. Fresh water use includes river and rain water (green water) and relates to water withdrawal, thus no statement about the fate
of the water withdrawal is made (see appendix a). Water use also includes water used for the provision of energy, where water used for cooling and the provision of hydro energy plays a key role.
1
17rESuLTS
the environment (e.g. freshwater depletion and impacts to biodiversity). in the assessment of water consumption it is crucial where the water consumption takes place. in water abundant areas the effects of water consumption will have a very low impact, while in dry areas the effects will be large. This difference is addressed by applying the water stress index (WSi) developed by PFiSTEr ET aL. 2009. The water stress index is used to weight water con-sumption according to regional availability, i.e. a multi-plication of consumptive water use with the water stress index (WSi). The resulting figure is called “water depriva-tion” (Figure 5). rain water is not considered in that cat-egory anymore (see appendix a for further information).
The total freshwater use to produce 1t of Gari is 661m³. most fresh water used occurs in processing. However, as mentioned above the direct water use in process-ing (washing of tubers) is rather a minor factor and the high value refers to the water used in the production of electricity required for processing (e.g. cooling water or turbine water). Freshwater consumption in processing is followed by the rain water consumption on field.
Following the rationale of BayarT ET aL. 2010 and the “water use in LCa” - working group of the uNEP-Setac, water footprinting in a LCa context focuses on the wa-ter lost to the watershed, i.e. water consumption. Water consumption is considered to have a direct impact on
Figure 5: Contribution of different life cycle phases to water deprivation (WSI)[m³] of 1t Gari
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
0,40
1t Gari
m/t
Upstream supply + Processing
it can be seen that only a minor fraction of the total freshwater use is relevant for environmental depletion in a narrow sense. 0.34m³ of water deprivation is caused by producing 1t of Gari. around two thirds of water depri-vation is caused in upstream processes, while around one
third of water deprivation can be attributed directly to water use during processing.
The next impact category to be investigated is land oc-cupation (Figure 6).
18 rESuLTS
5.1.2 Cassava Starch results are presented in the same order as for Gari. First, Figure 7 shows the GWP of 1t Starch and the contribu-tion of different life cycle phases.
Occupation of land refers to the maintenance of an area in a particular state over a particular time period. Obvi-ously this impact will be dominated by the agricultural phase, i.e. area required to cultivate the crop in question. a neglectable fraction (<0.5%) is associated with land oc-cupation in upstream processes. in average, 0.32ha are needed to produce 1t of Gari.
Figure 6: Contribution of different life cycle phases to land use (occupation) [ha*yr] of 1t Gari
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
1t Gari
ha*y
r/t
Upstream processes
Cassava cultivation
Figure 7: Contribution of different life cycle phases to carbon footprint of 1t Starch
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
1t Starch
t CO
2e/t
final
pro
duct
Transport
Processing
Pesticides
Field operations
Field emissions
Fertilizer
Crop rotation
Clearance
19rESuLTS
centrifugation, drying). This can be seen in the larger contribution of the processing phase to total GWP (see also Figure 8). However, largest contributors are still the field emissions during cultivation.
The carbon footprint of 1 t Starch from Cassava is 0.7t CO2e.2 The GWP is higher than for Gari because more cassava is used to make starch (ca. 5kg per kg) than to make Gari (4kg per kg). additionally, processing to starch is more elaborate than processing to Gari (e.g.
Figure 8: Contribution of different life cycle phases to carbon footprint of 1t Starch
68%
32%
Agriculture
Processing + Transport
Figure 9: Contribution of different life cycle phases to total freshwater use [m³] of 1t Starch
0 200 400 600 800
1000 1200
1t Starch
m/t
Upstream supply + Processing
Rain
2 The figure does not show the carbon dioxide uptake by the crop since the CO2 is biogenic and will be released later in the life cycle
as stated above, the higher processing demand of starch compared to Gari also results in a higher share (32%) of that phase to overall GWP.
Figure 9 shows the contribution of different phases to total fresh water use.
20 rESuLTS
with water. in combination with the larger amount of cassava needed to produce 1t of starch, the total water use is much higher for starch than for Gari. The same holds true for water deprivation (Figure 10).
The total freshwater use to produce 1t of starch from cassava is around 1000m³. Processing of starch has a large input of blue water both due to energy consumption and due to rasping where the starch is flushed out of the fibre
Figure 10: Contribution of different life cycle phases to water deprivation (WSI)[m³] of 1t Starch
0,0 2,0 4,0 6,0 8,0
10,0 12,0 14,0 16,0 18,0 20,0
1t Starch
m/t
Upstream supply + Processing
Figure 11: Contribution of different life cycle phases to land use (occupation) [ha*yr] of 1t Starch
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
4,00
1t Starch
ha*y
r/t
Upstream processes
Cassava cultivation
18m³ of water deprivation is caused by producing 1t of starch. as stated above, the main driver behind blue water use is the flushing out of starch from the tubers. a significant share of the water used ends up in the starch milk and is evaporated in the drying phase and thus
contributes to water consumption and consequently to water deprivation.
The last impact category to be investigated for starch is land occupation (Figure 11).
21rESuLTS
5.1.3 Maize feed flour Figure 12 shows the GWP of 1t maize feed and the con-tribution of different life cycle phases.
Similar to other impact categories the impact of starch on land occupation is also higher for starch than for Gari, because more cassava is used to make starch than to make Gari. in average, 0.37ha are needed to produce 1t of cassava starch.
Figure 12: Contribution of different life cycle phases to carbon footprint of 1t Maize feed
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
1t Maize feed
t CO
2e/t
final
pro
duct
Transport
Processing
Pesticides
Field operations
Field emissions
Fertilizer
Crop rotation
Clearance
Figure 13: Contribution of different life cycle phases to carbon footprint of 1t Maize feed
91%
9%
Agriculture
Processing + Transport
The carbon footprint of 1t maize feed is 0.73t CO2e.3 Comparable to the cassava products the agricultural phase, especially field emissions, is dominant for maize as well. Processing only plays a minor role in contribu-tion to GWP, because there is only one processing step
(milling). Transport has a neglectable impact because the transport distances reported in the surveys (OGuNTaDE 2012) are very short (<5km). The large contribution of ag-riculture to total GWP is further illustrated by Figure 13.
3 The figure does not show the carbon dioxide uptake by the crop since the CO2 is biogenic and will be released later in the life cycle
22 rESuLTS
Total freshwater use of maize feed is 371m³. No water is directly used during processing, that is why no water for processing is shown. Consequently, water deprivation is
Figure 14 shows the contribution of different phases to total fresh water use.
Figure 14: Contribution of different life cycle phases to total freshwater use [m³] of 1t maize feed
0
100
200
300
400
1t Maize feed
m/t Upstream supply
Rain
Figure 15: Contribution of different life cycle phases to water deprivation (WSI)[m³] of 1t Maize feed
0,0
0,1
0,1
0,2
0,2
0,3
0,3
0,4
0,4
1t Maize feed
m/t
Upstream supply
small and does also not include any direct consumption (Figure 15).
23rESuLTS
5.2.1 Impacts of the Cassava value chain
The quantities lost along the cassava value chain, the impact of the product per tonne and the total impact of the losses at the respective stage are given in Table 5. The sum of all impacts over the complete value chain is given in Table 6. Please refer to OGuNTaDE 2012 for details on why the losses occur. For instance, losses at the marketing phase are mainly due to storage (rodents and moisture), a smaller fraction is lost during transport (see also Table 5).
On average, 0.52ha are needed to produce 1t of maize feed flour.
5.2 Environmental Impact of Total Losses
To calculate the environmental impact of all losses oc-curring along the value chain, the loss quantities as reported in OGuNTaDE 2012 are multiplied with the impact of the product under study at the respective pro-cessing stage. afterwards all impacts occurring along the value chain are summed up to result in the total impact in a given impact category. The naming of the different steps in the value chain was adopted from OGuNTaDE 2012.
Figure 16: Contribution of different life cycle phases to land use (occupation) [ha*yr] of 1t Maize feed
0,00
0,10
0,20
0,30
0,40
0,50
0,60
1t Maize feed
ha*y
r/t
Upstream processes
Cassava cultivation
The last impact category to be investigated for maize feed flour is land occupation (Figure 16).
24 rESuLTS
Food
Los
s (f
arm
ers‘
qu
esti
onna
ire)
Mea
n
(%)
Ann
ual
Prod
. [M
io t]
Qty
Los
t [M
io t]
CF
of
prod
uct
(t C
O2 q
./t)
CF
of
Food
Los
s
[Mio
t]
Tota
l fr
eshw
ater
us
e [m
³/t]
Tota
l fre
sh-
wat
er u
se
[Mio
m³]
Wat
er d
e-
priv
atio
n (W
SI)
[m³/
t]
Wat
er d
e-
priv
atio
n (W
SI) [
Mio
m
³]
Land
use
(O
ccu-
pati
on)
[ha*
yr/t
]
Land
use
(O
ccup
a-ti
on) [
Mio
ha
*yr]
Qua
ntifi
cati
on o
f PH
L of
Fre
sh C
assa
va T
uber
at t
he F
arm
gate
Loss
dur
ing
harv
est (
dam
aged
tu-
bers
)4.
95
37.5
1.86
0.08
8
0.16
44.3
82.1
8
0.04
0.07
0.06
8
0.13
Loss
due
to s
mal
l siz
e1.
930.
720.
0632
.04
0.03
0.05
Loss
of f
resh
tube
r dur
ing
stor
age
1.63
0.61
0.05
27.0
60.
020.
04
Tota
l8.
513.
190.
2814
1.29
0.12
0.22
Qua
ntifi
cati
on o
f PH
L of
Fre
sh C
assa
va T
uber
at G
ari P
roce
ssin
g Ph
ase
Loss
dur
ing
tran
spor
tatio
n of
cas
sa-
va tu
bers
2.
2
26.3
0.58
0.10
5
0.06
48.7
28.1
5
0.05
0.03
0.07
4
0.04
Dis
card
sm
all t
uber
s 5.
81.
520.
1674
.22
0.07
0.11
Dis
card
woo
dy tu
bers
4.
11.
080.
1152
.47
0.05
0.08
Tota
l12
.13.
180.
3315
4.85
0.15
0.24
Qua
ntifi
cati
on o
f PH
L of
Gar
i at P
roce
ssin
g Ph
ase
Loss
of fi
nish
ed p
rodu
ct (G
ari)
du-
ring
proc
essi
ng
1.6
6.6
0.11
0.56
4
0.06
643.
3
67.5
6
0.30
0.03
0.31
4
0.03
Loss
of G
ari d
urin
g st
orag
e du
e to
sp
oila
ge
1.11
0.07
0.04
46.8
70.
020.
02
Tota
l2.
710.
180.
1011
4.42
0.05
0.06
Qua
ntifi
cati
on o
f PH
L of
Gar
i at M
arke
ting
Pha
se
Loss
of G
ari d
urin
g tr
ansp
orta
tion
2.5
6.6
0.16
0.58
0
0.10
661.
3
108.
50
0.34
0.06
0.32
3
0.05
Loss
of G
ari d
urin
g st
orag
e du
e to
m
oist
ure
4.5
0.30
0.17
195.
300.
100.
10
Loss
of G
ari d
urin
g st
orag
e du
e to
ro
dent
att
ack
2.5
0.16
0.10
108.
500.
060.
05
Tota
l9.
50.
620.
3641
2.30
0.21
0.20
Qua
ntifi
cati
on o
f PH
L of
Cas
sava
Sta
rch
duri
ng P
roce
ssin
g an
d St
orag
e
Loss
Sta
rch
durin
g Pr
oces
sing
5.5
0.9
0.05
0.61
7
0.03
886.
3
43.8
8
15.9
0.79
0.32
5
0.02
Loss
of S
tarc
h du
ring
Stor
age
6.3
0.06
0.03
50.2
60.
900.
02
Tota
l11
.80.
110.
0794
.14
1.69
0.03
Tabl
e 5:
Qua
ntiti
es lo
st a
long
the
cass
ava
valu
e ch
ain,
impa
ct o
f the
pro
duct
and
tota
l im
pact
of l
osse
s
25rESuLTS
Figure 17 shows the contribution of the losses at differ-ent processing phases to the total GWP of losses in the cassava value chain.
Because the total quantity of starch processed and lost is small, this phase contributes only little to the total GWP of Cassava losses. The same holds true for Gari lost in the processing phase. all other losses contribute almost equally to the GWP of Cassava losses. all losses together add up to a GWP of 1.14 million tonnes of CO2e.
Summary of Cassava PHL Quantification
Qty Lost [Mio t]
CF of Food Loss
[Mio t]
Total fresh-water use [Mio m³]
Water deprivation
(WSI) [Mio m³]
Land use (Occupa-tion) [Mio ha*yr]
Cassava Tuber at the Farm Gate 3.2 0.28 141.3 0.1 0.22
Cassava Tuber at Processing Phase 3.2 0.33 154.8 0.2 0.24
Gari at Processing Phase 0.2 0.10 114.4 0.1 0.06
Gari at Marketing Phase 0.6 0.36 412.3 0.2 0.20
Cassava Starch during Processing and Storage 0.1 0.07 94.1 1.7 0.03
Total Losses 7.28 1.14 917.0 2.2 0.7
Table 6: Summary of environmental impact of cassava PHL
Figure 17: Carbon footprint of PHL of Cassava
0,0
0,2
0,4
0,6
0,8
1,0
1,2
Total Losses
Mill
ion
t CO
2e
Cassava Starch during Processing and Storage Garri at Marketing Phase
Garri at Processing Phase
Cassava Tuber at Processing Phase
Cassava Tuber at the Farmgate
Figure 18 shows the contribution of the losses at differ-ent processing phases to the total freshwater use of losses in the cassava value chain.
26
The contribution of the different processing phases to freshwater use shows a similar pattern as for the GWP. again, the different contributions are mainly driven by the different quantities lost. However, this picture chang-
es when water deprivation is considered (Figure 19). all losses together add up to a freshwater use of 917 million m³.
rESuLTS
Figure 18: Total freshwater use of PHL of Cassava
0 100 200 300 400 500 600 700 800 900
1000
Total Losses
Mill
ion
m
Cassava Starch during Processing and Storage
Garri at Marketing Phase
Garri at Processing Phase
Cassava Tuber at Processing Phase
Cassava Tuber at the Farmgate
Figure 19: Water deprivation (WSI) of PHL of Cassava
0,0
0,5
1,0
1,5
2,0
2,5
Total Losses
Mill
ion
m
Cassava Starch during Processing and Storage
Garri at Marketing Phase
Garri at Processing Phase
Cassava Tuber at Processing Phase
Cassava Tuber at the Farmgate
as shown in Figure 10, starch is comparatively strong in water deprivation, while other processing phases are only contributing little to water deprivation. Consequently, the water deprivation impact category is dominated by
starch processing despite the small quantity of starch be-ing lost. all losses together add up to a water deprivation of 2.2 million m³.
27rESuLTS
ferent stages is again determining the contribution to the aggregated impact. all losses together add up to a land occupation of 0.7 million ha.
Figure 20 shows the contribution of the losses at differ-ent processing phases to land occupation of losses in the cassava value chain. Here the quantity of losses at the dif-
Figure 20: Land use (Occupation) of PHL of Cassava
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
Total Losses
Mio
. ha*
yr
Cassava Starch during Processing and Storage
Garri at Marketing Phase
Garri at Processing Phase
Cassava Tuber at Processing Phase
Cassava Tuber at the Farmgate
5.2.2 Impacts of the maize value chainThe quantities lost along the maize value chain, the im-pact of the product per tonne and the total impact of the losses at the respective stage are given in Table 7. The sum of all impacts over the complete value chain is given in Table 8.
28 rESuLTSFo
od L
oss
(far
mer
s‘
ques
tion
nair
e)M
ean
(%
)A
nnua
l Pr
od.
[Mio
t]
Qty
Los
t [M
io t]
CF
of p
ro-
duct
at t
hat
stag
e (t
CO
2 eq
./t)
CF
of
Food
Los
s
[Mio
t]
Tota
l fr
eshw
ater
us
e [m
³/t]
Tota
l fre
sh-
wat
er u
se
[Mio
m³]
Wat
er d
e-
priv
atio
n (W
SI) [
m³/
t]
Wat
er d
e-
priv
atio
n (W
SI) [
Mio
m
³]
Land
use
(O
ccu-
pati
on)
[ha*
yr/t
]
Land
use
(O
ccup
a-ti
on) [
Mio
ha
*yr]
Qua
ntifi
cati
on o
f PH
L of
Mai
ze c
obs
(gre
en a
nd d
ry) a
t far
m g
ate
Loss
dur
ing
harv
estin
g4.
03
0.71
0.03
0.18
0.01
93.4
2.66
0.08
0.00
0.14
0.00
Loss
of d
ry m
aize
cob
s du
ring
st
orag
e2.
270.
020.
001.
500.
000.
00
Tota
l6.
30.
040.
014.
150.
000.
01
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s at
farm
gat
e
Loss
dur
ing
harv
estin
g4.
03
7.31
0.29
0.39
0.11
196.
5
57.8
7
0.17
0.05
0.30
0.09
Loss
dur
ing
shel
ling
1.53
0.11
0.04
21.9
70.
020.
03Lo
ss o
f dry
mai
ze g
rain
dur
ing
st
orag
e2
0.15
0.06
28.7
20.
030.
04
Tota
l3.
530.
550.
2110
8.55
0.10
0.17
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s du
ring
Mar
keti
ng
Loss
dur
ing
tran
spor
tatio
n3.
7
7.31
0.27
0.42
0.11
212.
7
57.5
0
0.19
0.05
0.33
0.09
Loss
of m
aize
gra
ins
durin
g st
orag
e
due
to s
pilla
ge5.
90.
430.
1891
.69
0.08
0.14
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
Rod
ents
60.
440.
1993
.24
0.08
0.14
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
wee
vils
8.5
0.62
0.26
132.
090.
120.
20
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
exc
ess
moi
stur
e2.
50.
180.
0838
.85
0.03
0.06
Tota
l26
.61.
940.
8241
3.36
0.37
0.63
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s du
ring
Fee
d M
illin
gA
mou
nt o
f mai
ze g
rain
lost
dur
ing
tran
spor
tatio
n2
1.20
0.02
0.58
0.01
289.
8
6.96
0.26
0.01
0.44
0.01
Am
ount
of t
he m
aize
gra
ins
spo
ilt
in s
tora
ge2
0.02
0.01
6.96
0.01
0.01
Spoi
lage
of m
aize
gra
ins
in s
tora
ge
due
to ro
dent
s2.
80.
030.
029.
740.
010.
01
Spoi
lage
mai
ze g
rain
s in
sto
rage
due
to
Wee
vils
10.
010.
013.
480.
000.
01
Tota
l7.
80.
090.
0527
.13
0.02
0.04
Qua
ntifi
cati
on o
f PH
L of
Fee
d du
ring
Mar
keti
ngA
mou
nt o
f pr
oduc
t (fe
ed) l
ost
durin
g tr
ansp
orta
tion
3
2.00
0.06
0.68
0.04
345.
4
20.7
2
0.36
0.02
0.48
0.03
Am
ount
of p
rodu
ct (f
eed)
lost
du
ring
stor
age
due
to s
pilla
ge2
0.04
0.03
13.8
10.
010.
02
Am
ount
of p
rodu
ct (f
eed)
lost
sd
urin
g st
orag
e d
ue to
Wee
vils
20.
040.
0313
.81
0.01
0.02
Tota
l7
0.14
0.10
48.3
50.
050.
07
Tabl
e 7:
Qua
ntiti
es lo
st a
long
the
mai
ze v
alue
cha
in, i
mpa
ct o
f the
pro
duct
and
tota
l im
pact
of l
osse
s
29rESuLTS
as it can be seen from Table 8, most of the maize is lost during distribution. Consequently, this phase has the highest impact to the total GWP of losses in the maize value chain. all losses together add up to a GWP of 1.19 million tonnes of CO2e.
Food
Los
s (f
arm
ers‘
qu
esti
onna
ire)
Mea
n
(%)
Ann
ual
Prod
. [M
io t]
Qty
Los
t [M
io t]
CF
of p
ro-
duct
at t
hat
stag
e (t
CO
2 eq
./t)
CF
of
Food
Los
s
[Mio
t]
Tota
l fr
eshw
ater
us
e [m
³/t]
Tota
l fre
sh-
wat
er u
se
[Mio
m³]
Wat
er d
e-
priv
atio
n (W
SI) [
m³/
t]
Wat
er d
e-
priv
atio
n (W
SI) [
Mio
m
³]
Land
use
(O
ccu-
pati
on)
[ha*
yr/t
]
Land
use
(O
ccup
a-ti
on) [
Mio
ha
*yr]
Qua
ntifi
cati
on o
f PH
L of
Mai
ze c
obs
(gre
en a
nd d
ry) a
t far
m g
ate
Loss
dur
ing
harv
estin
g4.
03
0.71
0.03
0.18
0.01
93.4
2.66
0.08
0.00
0.14
0.00
Loss
of d
ry m
aize
cob
s du
ring
st
orag
e2.
270.
020.
001.
500.
000.
00
Tota
l6.
30.
040.
014.
150.
000.
01
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s at
farm
gat
e
Loss
dur
ing
harv
estin
g4.
03
7.31
0.29
0.39
0.11
196.
5
57.8
7
0.17
0.05
0.30
0.09
Loss
dur
ing
shel
ling
1.53
0.11
0.04
21.9
70.
020.
03Lo
ss o
f dry
mai
ze g
rain
dur
ing
st
orag
e2
0.15
0.06
28.7
20.
030.
04
Tota
l3.
530.
550.
2110
8.55
0.10
0.17
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s du
ring
Mar
keti
ng
Loss
dur
ing
tran
spor
tatio
n3.
7
7.31
0.27
0.42
0.11
212.
7
57.5
0
0.19
0.05
0.33
0.09
Loss
of m
aize
gra
ins
durin
g st
orag
e
due
to s
pilla
ge5.
90.
430.
1891
.69
0.08
0.14
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
Rod
ents
60.
440.
1993
.24
0.08
0.14
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
wee
vils
8.5
0.62
0.26
132.
090.
120.
20
Loss
of m
aize
gra
ins
durin
g st
orag
e du
e to
exc
ess
moi
stur
e2.
50.
180.
0838
.85
0.03
0.06
Tota
l26
.61.
940.
8241
3.36
0.37
0.63
Qua
ntifi
cati
on o
f PH
L of
Mai
ze g
rain
s du
ring
Fee
d M
illin
gA
mou
nt o
f mai
ze g
rain
lost
dur
ing
tran
spor
tatio
n2
1.20
0.02
0.58
0.01
289.
8
6.96
0.26
0.01
0.44
0.01
Am
ount
of t
he m
aize
gra
ins
spo
ilt
in s
tora
ge2
0.02
0.01
6.96
0.01
0.01
Spoi
lage
of m
aize
gra
ins
in s
tora
ge
due
to ro
dent
s2.
80.
030.
029.
740.
010.
01
Spoi
lage
mai
ze g
rain
s in
sto
rage
due
to
Wee
vils
10.
010.
013.
480.
000.
01
Tota
l7.
80.
090.
0527
.13
0.02
0.04
Qua
ntifi
cati
on o
f PH
L of
Fee
d du
ring
Mar
keti
ngA
mou
nt o
f pr
oduc
t (fe
ed) l
ost
durin
g tr
ansp
orta
tion
3
2.00
0.06
0.68
0.04
345.
4
20.7
2
0.36
0.02
0.48
0.03
Am
ount
of p
rodu
ct (f
eed)
lost
du
ring
stor
age
due
to s
pilla
ge2
0.04
0.03
13.8
10.
010.
02
Am
ount
of p
rodu
ct (f
eed)
lost
sd
urin
g st
orag
e d
ue to
Wee
vils
20.
040.
0313
.81
0.01
0.02
Tota
l7
0.14
0.10
48.3
50.
050.
07
Summary of Cassava PHL Quantification
Qty Lost [Mio t]
CF of Food Loss
[Mio t]
Total fresh-water use [Mio m³]
Water deprivation
(WSI) [Mio m³]
Land use (Occupa-tion) [Mio ha*yr]
Maize cobs at farm gate 0.04 0.01 4.15 0.00 0.01
Maize grains at farm gate 0.55 0.21 108.6 0.10 0.17
Maize grains during Marketing 1.94 0.82 413.4 0.37 0.63
Maize grains during Feedmilling 0.09 0.05 27.1 0.02 0.04
Feed during Marketing 0.14 0.10 48.4 0.05 0.07
Total Losses 2.77 1.19 601.5 0.54 0.91
Table 8: Summary of environmental impact of maize PHL
Figure 21 shows the contribution of the losses at differ-ent processing phases to the total GWP of losses in the maize value chain. Here the quantity of losses at the dif-ferent stages is again determining the contribution to the aggregated impact.
Figure 21: Carbon footprint of PHL of Maize
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
Total Losses
Mill
ion
t CO
2e Feed during Milling and Marketing
Maize grains during Feedmilling
Maize grains during Marketing
Maize grains at farmgate
Maize cobs at farmgate
The domination of the losses during distribution can be found in all other investigated impact categories as well (Figure 22 - Figure 24).
30 rESuLTS
all losses together add up to a freshwater use of 602 million m³.
Figure 22: Total freshwater use of PHL of Maize
0
100
200
300
400
500
600
700
Total Losses
Mill
ion
m Feed during Milling and Marketing
Maize grains during Feedmilling
Maize grains during Marketing
Maize grains at farmgate
Maize cobs at farmgate
Figure 23: Water deprivation (WSI) of PHL of Maize
0,00
0,10
0,20
0,30
0,40
0,50
0,60
Total Losses
Mill
ion
m Feed during Milling and Marketing
Maize grains during Feedmilling
Maize grains during Marketing
Maize grains at farmgate
Maize cobs at farmgate
Figure 24: Land use (Occupation) of PHL of Maize
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0
Total Losses
Mio
. ha*
yr Feed during Milling and Marketing
Maize grains during Feedmilling
Maize grains during Marketing
Maize grains at farmgate
Maize cobs at farmgate
all losses together add up to a water deprivation of 0.54 million m³.
all losses together add up to a land occupation of 0.91 million ha.
31rESuLTS
• Climate change – Due to changing temperature, pre-cipitation, and seasonality, emissions of greenhouse gases are expected to cause large number of terrestrial extinction over the next century. invasive alien species are also expected to have overall impacts in Europe due to climate change and on their own.
• Acidification and eutrophication – These issues lead to a disruption of the natural nutrient balance, altering the habitat condition and the specie composition in ecosystems, and leading to a loss of biodiversity.
• Ecotoxicity: This refers to the potential of biological, chemical and physical stressors to affect ecosystems. Stressors can occur in the natural environment or can be introduced to ecosystems through human activity, potentially at levels high enough to alter the natural biochemistry, physiology, behaviour and interactions of the living organisms that comprise an ecosystem. The use of chemicals in farming practices has the po-tential to cause ecotoxicological effects by reaching organisms through the pathways of air, water and soil.
This study covers two of the impact areas mentioned by Curran et al. 2011, water use and climate change. Before discussing the presented results with regard to impact on biodiversity, in the following a quick outlook on “land use change” is given to be added as indicator for impact on biodiversity.
5.3.3 Land use Change as indicator for impact on biodiversityLand use change in Nigeria shows an intensification of cultivation systems. according to FaO Statistics (2012), forest area in Nigeria decreased constantly over the past 20 years. at the same time (between 1990 and 2009) the area where cassava was cultivated almost doubled. in contrast, the area of maize grown and harvested in Nigeria decreased over the past 20 years (Figure 26).
Looking at the major ten crops grown in Nigeria over the past twenty years (Figure 26) indicates that besides Cas-sava, yams production doubled as well. it cannot clearly be stated whether these increases in production are driven by increases in yield and by replacing other crops or by deforestation. However, considering the decrease in
5.3 Qualitative assessment of impact on biodiversity
5.3.1 Biodiversity in the food supply chainFood production and the consumption of raw materi-als are derived from living systems. Though impacts of agriculture on biodiversity vary according to production systems, humanity avails itself on ecosystem services and intervenes indispensably in the habitat of animals and vegetation, by converting land and forests into agri-cultural cropland, using water, and emitting greenhouse gases. at the same time the capability of many eco-sys-tems to meet this demand is diminishing (uNEP 2005). Food loss is linked to biodiversity, because it illustrates a certain amount of food that is not used or consumed but its production affected biodiversity (Eu 2012).
5.3.2 Impact of food production on biodiversity within a LCAFor environmental impacts such as biodiversity and land use the evaluation methodology is not yet fully devel-oped. The assessment of these impacts are classified with ii and iii in the iLCD handbook (“recommended, but to be applied with caution”, iLCD 2011). The iLCD Hand-book compares different approaches to asses impacts on biodiversity on different levels (see appendix B). Since then, additional methods have been proposed. Curran et al. (2011) suggest using existing LCa impact categories to assess the impact on biodiversity. according to Curran et al. (2011), the relation of LCa midpoint impact categories to biodiversity loss are as follows:
• Land use change – The uNEP states that in the past years, the increase in food demand has led to an inten-sification of cultivation systems. Both, the expansion of production areas and the production of biofuels has led to the conversion of natural or close-to-natural land use types into managed ones. This conversion of natural habitat to human use has been the main driver of biodiversity loss over the past decades.
• Water use – blue water polluted by anthropogenic activities does not only reduce regional resource avail-ability, but also affects the functioning and diversity of water-dependent terrestrial and freshwater ecosys-tems.
32 rESuLTS
forest area it is likely that at least some of the increases in production and cultivated area of cassava and yam is due to displacing forest.
5.3.4 Conclusion – impact on biodiversityThe impact assessment of production systems with re-gard to biodiversity is still in its infancy. Therefore this
Figure 25: Area development of forest, cassava production and maize production in Nigeria (1990 and 2009)
33rESuLTS
ricultural productions systems are of especial relevance to biodiversity.
The results show also that water use is also an issue in the cassava and maize value chain, whereas probably not as much of concern as the impacts on climate change. This is partly because the systems under study are not irrigated. Furthermore, even though there is water used in processing, no large burden in terms of toxicity or pol-lutants is caused by the water usage. it has to be stated though that the large quantities of water used for hydro power generation can possibly threaten biodiversity.
all seen together, considering biodiversity can only ag-gravate the concern about preventable environmental burden caused by food losses.
Figure 26: Top Ten crop production in Nigeria in 1990 (left) and 2010 (right).
study abstains from giving a quantitative assessment. in the following a qualitative assessment based on the given impact categories is given.
as the results presented above indicate, food losses in the cassava and maize value chain contribute significantly to climate change. impacts on biodiversity caused by climate change will only occur in the long term and will not be directly traceable to the agricultural production system. Still, agricultural production constitutes a two-fold burden on biodiversity, with its impact on climate change and its impact on land use change. Some further impacts such as soil erosion potentially add to the pres-sure on the environment. it has thus to be stated that ag-
34 ENvirONmENTaL FOOTPriNT OF FOOD LOSSES iN NiGEria – SETTiNG THEm iNTO PErSPECTivE
not directly comparable, relatively to cotton in the uS the water deprivation values of Gari and maize being around 0.3m³ per tonne do not carry much weight. Starch with its 18m³ per tonne is already a bit more of concern. The water stress index (WSi) applied for Nigeria is 0.29. values above 0.2 already indicate moderate water stress (PFiSTEr ET aL. 2009). Water should therefore always be considered in environmental investigations in this region. That said it has to be stated that applying a WSi aggregated for the whole country is a severe simpli-fication as water availability might vary strongly within one country, especially if it covers climatically diverse zones as Nigeria does. a more detailed look into water use, water consumption and water deprivation might thus be a beneficiary field for further investigations.
Looking at the environmental footprint summed up over the complete value chain, it can be seen that the food losses investigated in this study indeed have a large environmental footprint. The losses in the cassava and maize value chain together contribute to around 2.3 million tonnes of CO2e to the atmosphere. according to the WOrLD BaNK 2013), the per capita emissions in Nigeria are 0.5t per person and year (between 2008 and 2012). That would mean that the food losses equal the emissions of four and half million Nigerians. This num-ber seems to be very high. Given the importance of both crops in the Nigerian food sector and taking into account that 27% (Cassava) or 31% (maize) of the total quantity produced is lost over the complete value chain (own cal-culation based on OGuNTaDE 2012), a high impact is in-deed likely. On the other hand, building on the same data from WOrLD BaNK 2013, 2.3 million tonnes would rep-resent 3.3% of total GHG emissions in Nigeria. although national GHG inventories have to be interpreted with care (with regard to system boundaries and assumptions) as well, this gives an indication that production quanti-ties, loss rate and/or emission factors presented in this study are more likely to be seen on the worst case side of the possible impact scale. However, these values are also a clear indicator that food losses are contributing signifi-cantly to global GHG emissions (see also FaO 2012).
in the following section the results shown in chapter 5 should be discussed and set into perspective. To do this, different comparisons are made in order helping to understand the impact of food losses of cassava and maize in Nigeria. it has to be stated though, that the re-sults must be interpreted with utmost care. Both, data on quantities of food losses and inventory data to cal-culate the environmental footprint are subject to large uncertainties. The production quantities and losses as outlaid in OGuNTaDE 2012 are not fully consistent. The interpretation should thus be done in a way to identify potential impacts and areas of concern rather than trying to give precise and definite numbers.
To begin with, a comparison of the carbon footprint of maize and cassava at field edge with similar products should be made. as shown in Figure 3 and Figure 5, agri-culture is the main contributor to the Carbon Footprint of all products. Cassava tubers leave the field with a CF of 0.088 kg CO2e/t (Table 5), whereas maize grains leave the field with 0.39 kg CO2e/t (Table 7). Benchmarking against existing datasets from PE iNTErNaTiONaL reveals that these values lay in range but are higher than values for more industrialized cultivation in other regions.
a reason for that has to be searched in the low yields reported in OGuNTaDE 2012. Especially for cassava, the yield reported in the farmers survey is more than half compared to the yield reported by FaO STaT for Nigeria (5t/ha vs. 12t/ha), and almost only a quarter of the yield in large cassava producing countries like Thailand (19t/ha, FaO STaT). Some emissions during cultivation are in-evitable, and if yields are low, the environmental burden of cultivation is distributed to a less amount of product, consequently leading to high burdens per tonne of prod-uct leaving the field.
Since cassava is cultivated under a rain fed regime, blue water use and water deprivation is not likely to be the environmental issue of most concern. Water deprivation values investigated by PE iNTErNaTiONaL for cotton cultivation in the uS gave a range of 4m³ to >2000m³ per tonne of seed cotton. Even though these products are
6 Environmental Footprint of Food Losses in Nigeria – Setting them into Perspective
35ENvirONmENTaL FOOTPriNT OF FOOD LOSSES iN NiGEria – SETTiNG THEm iNTO PErSPECTivE
To set water use into perspective is complex. at the moment there is an on-going debate in the LCa com-munity on how to relate water consumption to human health, environmental health or resource depletion. The cause-effect chains are highly complex and very hard to express in numbers. Thus no direct connection to these endpoints can be given in this report. To allow at least to set the order of magnitude into perspective, a useful fig-ure given by the uNESCO is that 50 litre per person and day are needed to ensure their basic needs for drinking, cooking and cleaning (WWaP 2009). This equals 19m³ needed per person per year. The losses along the cassava and maize value chain account for a water deprivation of 2.8 million m³. Per definition water deprivation means that it is lost for further use. That means that this amount of water lost could have potentially served around 150000 people.
Land occupation is more straight-forward to be set into perspective. in Nigeria around 3.5 million hectare are planted with Cassava and 4.2 million ha with maize (in 2010, FaO STaT). Land occupation due to losses in sum accounts for 1.7 million ha. That means that land occupation trough losses accounts for 21% of the area cultivated with maize and cassava. Given the large vari-ation between different years and possible discrepancies between area cultivated, yield, losses and production quantity within the values reported in FaO STaT and OGuNTaDE 2012, these values fit reasonably well to the reported losses (27% for Cassava, 31% for maize).
36 OPTiONS FOr miTiGaTiON
7 Options for Mitigation
in focus of any mitigation measure to reduce the envi-ronmental impact of food losses must be to reduce the occurring food losses itself. OGuNTaDE 2012 provides an extensive elaboration of possible measures to reduce food losses, such as improved storage facilities and im-proved access to markets. also suggestion for policies and stakeholder involvement are made. Please refer to OGuNTaDE 2012 for full reference of these kinds of mitigation options. Some mitigation options specific to the environmental footprint should be added here.
in focus should be improvements in agricultural cultiva-tion. a more efficient use of land and water resources might increase the productivity of agricultural produc-tion systems and potentially lower its environmental burden. For instance, the use of organic fertilizer can in-crease soil fertility, provide nutrients and lead to higher yields and improve water retention. a possible measure might be the incorporation of plant residues rather than burning them, in order to increases soil fertility and pre-vent emissions due to clearance.
in terms of water, additional to increased water use ef-ficiency due to improved agricultural productivity, water might also be saved during processing. Different reuse options of water in starch processing can reduce water use by 15% (SriNOPHaKuN ET aL. 2000).
Building on suggestions made by OGuNTaDE 2012, building cooperatives to organize processing could allow higher efficiency due to the reduction of losses and lower energy use per tonne in larger machines.
37CONCLuSiON
8 Conclusion
The issue of food losses is of high importance in the ef-forts to combat hunger, raise income and improve food security in the world’s poorest countries. However, food losses also represent a waste of resources used in produc-tion such as land, water, energy and inputs. This study provided strong evidence that the environmental impact of food losses is relevant and important to be considered. a reduction in food losses will benefit both, humanity and the environment.
analysis of the life cycle of the products (Gari, Cassava starch, maize feed) revealed that their environmental impact is mainly caused by agricultural cultivation. Pro-cessing is relevant with regard to water consumption in starch processing and energy consumption. Looking at the environmental impact of losses over the complete value chain of cassava showed that losses at farm gate and during storage at different phases had the largest im-pact. Losses during processing of cassava and starch were less relevant, mainly because the amounts lost at these stages are small. analysis of the maize value chain gave a similar picture. The large amounts of losses occurring during storage at different phases are reflected in large contributions to the environmental impact.
The impact assessment of production systems with regard to biodiversity is difficult to quantify. Neverthe-less, it can be stated that a direct linkage can be made from each impact category assessed in this report to
biodiversity. Considering biodiversity can therefore only strengthen the concerns on preventable environmental burden caused by food losses.
The total environmental impact of all losses together is significant, even when set into perspective to resource use of Nigeria as a whole. To reduce food losses in the agricultural sector could therefore lead to strong benefits to the countries’ efforts to combat climate change on to save resources.
The results presented in the first part of the investiga-tions of the GiZ (OGuNTaDE 2012) and this study are a large step ahead in gaining more insight into the dynam-ics of food losses and their environmental impact in Ni-geria and potentially in africa as whole. yet more needs to be done. many studies investigating food losses in different contexts found that data insecurity is a large is-sue, a problem that could not be completely ruled out by this study as well. Further investigation, validation of the numbers generated so far and further details are needed to make reliable quantitative claims.
Finally, LCa is not meant to be a self-contained art. Only if companies, policy makers, civil society and citizens un-derstand the necessity of a responsible use of resources and only if they are provided with methods and tools to calculate and evaluate, the final goal of environmental impact assessment can be reached.
38 rEFErENCES
9 References
BAYART ET AL. 2010
Bayart, J.B.; Bulle, C.; Koehler, A.; Margni, M.; Pfister, S.; Vince, F.; Deschenes, L. (2010): A framework for assessing off-stream freshwater use in LCA, Int J Life Cycle Assess 15, 439–453
CURRAN ET AL. 2011
Curran, M. et al. (2011), Toward Meaningful End Points of Biodiversity in Life Cycle Assess-ment, Environmental Science & Technology, Vol. 45, 70-79.
ENVIFOOD 2012
European Food Sustainable Consumption & Production Round Table: Envifood Protocol – Environmental Assessment of Food and Drink Protocol. Draft Version 0.1 (November 2012)
FAO 2010
FAO (2010): FAOSTAT database, Food and Agriculture Organization, Rome, Italy, available online (06.03.2013): http://faostat.fao.org
FAO 2011
J. Gustavsson et al. (2011) Global food losses and food waste; extent, causes and prevention, Study conducted for the International Congress SAVE FOOD! at Interpack2011 Düsseldorf, Germany
FAO 2012 Food Wastage Footprint – Interim report FAO NRDD
GABI 5 GaBi 5 Ssoftware-System and Database for Life Cycle Engineering. PE INTERNATIONAL AG, Copyright, TM. Stuttgart, Echterdingen 1992-2012.
HOEKSTRA ET AL. 2009
Hoekstra, A.Y.; Chapagain, A.K.; Aldaya, M.M.; Mekonnen, M.M. (2009): Water Footprint Manual. State of the Art 2009; Water footprint Network: Enschede, The Netherlands
ILCD 2011
European Commission-Joint Research Centre - Institute for Environment and Sustainability: International Reference Life Cycle Data System (ILCD) Handbook- Recommendations for Life Cycle Impact Assessment in the European context. First edition November 2011. EUR 24571 EN. Luxemburg. Publications Office of the European Union; 2011
IPCC 2006
Intergovernmental Panel on Climate Change (2006) Guidelines for National Greenhouse Gas Inventories. Retrieved from http://www.ipcc-nggip.iges.or.jp/ (Jan2013)
ISO 2006
ISO. (2006): International Standard, ISO 14040, Environmental management – life cycle assessment – principles and framework, 2006. Geneva: International Standard Organization.
OGUNTADE 2013
Reducing Food Losses to Improve Food Security: An Analysis of Cassava and Maize Value Chains in Nigeria, report delivered to the GIZ 2012
PFISTER ET AL. 2009
Pfister, S.; Koehler, A.; Hellweg, S. (2009): Assessing the environmental impact of freshwater consumption in LCA. Environ Sci Technol 43(11), 4098–4104.
SRINOPHAKUN ET AL. 2000
T. Srinophakun et al. (2000): Water-Wastewater Management of Tapioca Starch Manufacturing Using Optimization Technique, ScienceAsia 26 (2000) : 57-67
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United Nations, 1992, Convention on Biological Diversity, retrieved from http://www.cbd.int/doc/legal/cbd-en.pdf
UNEP 2005
United Nations Environment Programme, 2005, Millennium Ecosystem Assessment, retrieved from http://www.unep.org/maweb/documents/document.48.aspx.pdf
WORLD BANK 2013
CO2 emissions (metric tons per capita); Carbon Dioxide Information Analysis Center, Environmental Sciences Division, Oak Ridge National Laboratory, Tennessee, United States; Retrieved from http://data.worldbank.org/indicator/EN.ATM.CO2E.PC (Jan 2013)
WWAP 2009
World Water Assessment Programme (2009): The United Nations World Water Development Report 3: Water in a Changing World, UNESCO, Paris and Earthscan London.
39aPPENDix a: DESCriPTiON OF imPaCT CaTEGOriES
Appendix A: Description of Impact Categories
Global Warming Potential (GWP)
The mechanism of the greenhouse effect can be observed on a small scale, as the name suggests, in a greenhouse. These effects are also occurring on a global scale. The oc-curring short-wave radiation from the sun comes into contact with the earth’s surface and is partly absorbed (leading to direct warming) and partly reflected as infra-red radiation. The reflected part is absorbed by so-called greenhouse gases in the troposphere and is re-radiated in all directions, including back to earth. This results in a warming effect at the earth’s surface.
in addition to the natural mechanism, the greenhouse effect is enhanced by human activities. Greenhouse gases that are considered to be caused, or increased, anthropo-genically are, for example, carbon dioxide, methane and CFCs. Figure a 1 shows the main processes of the anthro-pogenic greenhouse effect. an analysis of the greenhouse effect should consider the possible long term global ef-fects.
The global warming potential is calculated in carbon di-oxide equivalents (CO2 -Eq.). This means that the green-house potential of an emission is given in relation to CO2
Since the residence time of the gases in the atmosphere is incorporated into the calculation, a time range for the assessment must also be specified. a period of 100 years is customary.
Figure 27: Greenhouse effect
UV - radiation
AbsorptionReflection
Infraredradiation
CO2 CH4
CFCs
40 aPPENDix a: DESCriPTiON OF imPaCT CaTEGOriES
Water footprint
Terminology: Water use is understood as umbrella term for all types of anthropogenic water uses. On inventory level, water use equals the measured water input into a product system or process. in most cases water use is determined by total water withdrawal (water abstraction).
1. Freshwater and sea water Freshwater is naturally occurring water on the Earth’s surface in ponds, lakes, rivers and streams, as ice, and underground as groundwater in aquifers and under-ground streams. The term specifically excludes seawa-ter and brackish water. Typically freshwater resources lay in the focus of anthropogenic water use. However, in addition to the use of freshwater, water use may also include other water from other sources, such as brack-ish water and sea water. Water footprinting typically only considers freshwater resources as only freshwater use is relevant from an impact assessment perspective because freshwater is a limited natural resource.
2. Green and blue water an important subdivision of water use is the differen-tiation of blue water and green water.
• Greenwater:rainwaterandmoisturestoredinsoilthat evaporates during production process, mainly during crop growth (evapotranspiration).
• Bluewaterreferstosurfaceandgroundwaterused(e.g. irrigation in crop cultivation and water used for cooling purposes).
in contrast to the method suggested by Hoesktra et al. and the Water Footprint Network, rain water, denoted green water, is not considered in assessment of environ-mental impacts of products, as appropriate life cycle im-pact assessment methods are lacking. The focus lays on water from ground and surface water bodies.4 However, on the inventory level rain water has to be accounted for in order to establish a correct water balance.
3. Consumptive and degradative use Freshwater use is generally differentiated into con-sumptive water use (= water consumption) and degred-ative water use, the latter denoting water pollution:
Freshwater consumption (consumptive freshwater use) describes all freshwater losses on a watershed level which are caused by evaporation, evapotranspiration from plants (Note: only water from irrigation is con-sidered in the assessment of agricultural processes, consumption of rain water is neglected, see above), freshwater integration into products, and release of freshwater into sea (e.g. from wastewater treatment plants located at the coast line). Thereby, freshwater consumption is defined in a hydrological context and should not be interpreted from an economic perspec-tive. Thus, it does not equal the total water use (total water withdrawal), but rather the associated losses during water use. Note that only the consumptive use of freshwater, not sea water is relevant from an impact assessment perspective because freshwater is a limited natural resource.
Degradative water use, in contrast, denotes the use of water with associated quality alterations and thus de-scribes the pollution of water (e.g. if tap water is trans-formed to wastewater during use). These alterations in quality are not considered to be water consumption!
The watershed level is regarded the appropriate geo-graphical resolution to define freshwater consump-tion (hydrological perspective). if groundwater is withdrawn for drinking water supply and the treated wastewater released back to a surface water body (river or lake), then this is not considered freshwater consumption if the release takes place within the same watershed; it is degradative water use. The difference between freshwater use and freshwater consumption is highly crucial to correctly quantify freshwater con-sumption, to interpret the meaning of the resulting values and for calculating water footprints.
4 The rationale behind this approach is the assumption that there is no environmental impact of green water (i.e. rain water) consumption. Such an effect would only exist if crop cultivation results in alterations in water evapotranspiration, runoff and infiltration compared to natural vegetation. if these alterations do not occur, the use of rainwater would not change the environmental effects that would take place if the studied system was not established. additionally it remains arguable whe-ther or not such changes (if they occur) should be covered by assessment of land use changes rather than in water inventories. However, rain water use is sometimes assessed in different methodological approaches or can be used for specific analyses.
41aPPENDix a: DESCriPTiON OF imPaCT CaTEGOriES
Biodiversity
according to the united Nation’s Convention on Bio-logical Diversity the term “biodiversity” refers to “the variability among living organisms from all sources in-cluding, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems”. The millennium Ecosystem assessment, a study commissioned by the united Na-tions Environmental Protection, emphasizes the impor-tance of conversing biodiversity in regards to ensuring environmental balance and the human well-being. it identifies terrestrial and aquatic habitat change, invasive species, over exploitation of wild populations, pollution, and climate change as the most important direct drivers of biodiversity loss. methods on how to assess impacts on biodiversity within a LCa framework are still under development (please refer to appendix B for further in-formation).
Water footprintThe water footprint of a system is a set of different cal-culations and should be used as an umbrella term rather than to communicate a single number. according to iSO 14046 (in progress) a water footprint consists of two parts: a water stress footprint caused by consumptive use and a water stress footprint caused by degradative water use.
Degradative use causes environmental impacts due to the pollutants released to nature. yet, quality alterations during degradative use, e.g. release of chemicals, are normally covered in other impact categories of an LCa, such as eutrophication and ecotoxicity. methods to assess additional stress to water resources caused by reduced availability of water (due to reduced quality) are under development. So far, water footprinting focuses on the water lost to the watershed, i.e. water consumption. Wa-ter consumption is considered to have a direct impact on the environment (e.g. freshwater depletion and impacts to biodiversity).
in the assessment of water consumption it is crucial where the water consumption takes place. in water abun-dant areas the effects of water consumption will have a very low impact, while in dry areas the effects will be large. This difference is addressed by applying the water stress index (WSi) developed by Pfister et al (2009). The water stress index is used to weight water consumption according to regional availability, i.e. a multiplication of consumptive water use with the water stress index (WSi). The resulting figure is called “water deprivation”. Water deprivation expresses the fraction of water which is rel-evant for Environmental Deficiency (rED water). Water deprivation will be lower than water use, but this is the fraction with environmental relevance. This can be con-sidered as midpoint category.
42 aPPENDix B: aSSESSiNG THE imPaCT OF FOOD PrODuCTiON ON BiODivErSiTy WiTHiN a LCa
Appendix B: Assessing the impact of food production on biodiversity within a LCA
For environmental impacts such as biodiversity and land use, the evaluation methodology is not yet fully developed. These impacts are classified with ii and iii in the iLCD handbook (“recommended, but to be applied with caution”,iLCD 2011). in the iLCD Handbook: “recommendations for Life Cycle impact assessment in the European context” (First edition), different ap-proaches to assess impacts on biodiversity are compared on different levels.
The methods considered at the midpoint level are:
• reCiPe,
• milà i Canals (2007) and
• Baitz (2002 further developed by Bos and Wittstock 2008)
at the endpoint level, the following methods have been evaluated:
• EPS2000,
• Eco-indicator 99,
• reCiPe,
• LimE and
• Swiss Ecoscarcity.
The conclusion of this comparison leads to the following statements;
• at midpoint, the method by milà i Canals et al. 2007 is classified as recommended, but to be applied with cau-tion (Level iii).
• at endpoint level, no method is recommended to be used. However, if an endpoint method is required, the reCiPe method can be used as an interim, as it is not mature enough for recommendation.
additional, recent developments exist but have not yet resulted in available characterisation factors and, there-fore, have not been further evaluated within the iLCD study. These include:
• michelsen (2007): The main value seems to lie in as-sessing biodiversity from an ecosystem rather than species diversity point of view. The study is focused on forestry, but a similar approach could be developed for other land–use types
• a new project group under the uNEP/SETaC Life Cy-cle initiative on land use.
The recently published Envifood Protocol (2012) states, that “although the development and inclusion of poten-tial endpoint indicators for biodiversity in LCa have been ongoing for several years, the underpinning methods for assessing some of the midpoints impacts are still under development. Consequently, an all-embracing endpoint indicator for biodiversity loss is not recommended at this stage and assessment should be done at mid-point level, which is still capable of providing meaningful indica-tions to address the magnitude of potential biodiversity loss” (Envifood Protocol, 2012). The Envifood Protocol is recommending a study of Curran et al. (2011).
43
Curran et al. (2011) conducted a review about studies dealing with the use of indicators and approaches to model biodiversity loss in LCas. amongst others, Curran et al. refer to a disproportionate focus on indicators that reflect changes in compositional aspects of biodiversity, mainly changes in species richness, to a considerable lack of functional and structural attributes of biodiversity, and the difficulties about taxonomic and geographic cov-erage, with the majority of models restricted to one or a few taxonomic groups and geographic regions (Curran et al., 2011).
a LCa reveals impacts along mostly linear, deterministic, cause-effect chains by linking inventory items to so-called midpoint impact categories. The approach is prob-lem-oriented and translates impacts into environmental themes, such as global warming potential, ecotoxicity, and land use. in an optional second step, the cause-effect chain is extended to final end-points as a damage-orient-ed approach and translates environmental impacts into issues of concern such as human health, ecosystem qual-ity, and natural resources. additionally, endpoint models generally include three components (Curran et al., 2011):
• fate factor models the spatial distribution and inten-sity of pressures induced by an intervention
• impact factor relates the intensity of an intervention to a quantified loss in biodiversity. it is frequently ex-pressed through the unit-less indicator “potentially disappeared fraction (PDF) of species”
• characterization factor multiplies the impact factor by the fate factor to give an endpoint of PDF*mx*yr
aPPENDix B: aSSESSiNG THE imPaCT OF FOOD PrODuCTiON ON BiODivErSiTy WiTHiN a LCa
44 aPPENDix C: SCENariO aNaLySiS – maNuaL PrOCESSiNG
Appendix C: Scenario analysis – Manual Processing
To investigate the role of energy consumption vs. manual labour a scenario is shown without any energy consump-tion along the processing chain. The results are only
shown for GWP, because here the energy consumption will be most clearly visible.
Figure 28: Manual labour scenario – cassava
0,0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
CF of Gari - mechanized processing (base scenario)
CF of Gari - manual processing
CF of starch - mechanized processing (base scenario)
CF of starch - manual processing
t CO
2e/t
final
pro
duct
as shown in Figure 3 and Figure 8, processing only plays a minor role in contribution to the carbon footprint of the staple products investigated in this study. Conse-quently, even if all processing were done manually with-
out any energy consumption the carbon footprint of the final product would only decrease by less than 10%, for both, maize and cassava products.
Figure 29: Manual labour scenario – maize feed
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
CF of maize feed - mechanized processing (base scenario)
CF of maize feed - manual processing
t CO
2e/t
final
pro
duct
45aPPENDix D: DaTa BaSE OF CaLCuLaTiON
Appendix D: Data Base of Calculation
The following tables show the production quantities as given in Oguntade 2013.
Food Loss (farmers‘ questionnaire) Mean (%)
Annual Prod. [Mio t]
Qty Lost [Mio t]
1) Quantification of PHL of Fresh Cassava Tuber at the Farmgate
Loss during harvest (damaged tubers) 4.95
37.5
1.86
Loss due to small size 1.93 0.72
Loss of fresh tuber during storage 1.63 0.61
Total 8.51 3.19
2a) Quantification of PHL of Fresh Cassava Tuber at Garri Processing Loss during transportation of cassava tubers (%) 2.2
26.3
0.58
Discard small tubers (%) 5.8 1.52
Discard woody tubers (%) 4.1 1.08
Total 12.1 3.18
3a) Quantification of PHL of Garri at Processing Phase Loss of finished product (Garri) during processing (%) 1.6
6.6
0.11
Loss of Garri during storage due to spoilage (%) 1.11 0.07
Total 2.71 0.18
4a) Quantification of PHL of Garri at Marketing Phase Loss of Garri during transportation 2.5
6.6
0.16
Loss of Garri during storage due to moisture 4.5 0.30
Loss of Garri during storage due to rodent attack 2.5 0.16
Total 9.5 0.62
3b) Quantification of PHL of Cassava Starch during Processing and Loss Starch during Processing 5.5
0.9
0.05
Loss of Starch during Storage 6.3 0.06
Total 11.8 0.11
Table 9: Production quantities and losses in the cassava value chain
46 aPPENDix D: DaTa BaSE OF CaLCuLaTiON
Food Loss (farmers‘ questionnaire) Mean (%)
Annual Prod. [Mio t]
Qty Lost [Mio t]
Quantification of PHL of Maize cobs (green and dry) at farm gate
Loss during harvesting 4.03
0.71
0.03
Loss of dry maize cobs during storage 2.27 0.02
Total 6.3 0.04
Quantification of PHL of Maize grains at farm gate Loss during harvesting 4.03
7.31
0.29
Loss during shelling 1.53 0.11
Loss of dry maize grain during storage 2 0.15
Total 3.53 0.55
Quantification of PHL of Maize grains during Marketing Loss during transportation 3.7
7.31
0.27
Loss of maize grains during storage due to spillage 5.9 0.43
Loss of maize grains during storage due to rodents 6 0.44
Loss of maize grains during storage due to weevils 8.5 0.62
Loss of maize grains during storage due to excess moisture 2.5 0.18
Total 26.6 1.94
Quantification of PHL of Maize grains during Feed Milling Amount of maize grain lost during transportation 2
1.20
0.02
Amount of the maize grains spoilt in storage 2 0.02
Spoilage of maize grains in storage due to rodents 2.8 0.03
Spoilage maize grains in storage due to Weevils 1 0.01
Total 7.8 0.09
Quantification of PHL of Feed during Marketing Amount of product (feed) lost during transportation 3
2.00
0.06
Amount of product (feed) lost during storage due to spillage 2 0.04
Amount of product (feed) lost during storage due to Weevils 2 0.04
Total 7 0.14
Table 10: Production quantities and losses in the maize value chain
47
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