What is a measure of total greenhouse gas emissions caused directly or indirectly by an organization a product an event or a person?

Abstract:

Carbon footprints estimate the total amount of greenhouse gases emitted during the production, processing and retailing of consumer goods. The aim is to identify major sources of emissions in supply chains to inform relevant stakeholders so that actions can be taken to reduce emissions. Carbon footprints can also be communicated to consumers via carbon labels. This chapter first describes the principles of carbon footprinting and labelling, and presents some examples of carbon footprints of food products. It then discusses problems in calculating carbon footprints and finally speculates on future developments of the methodology and its application.

2.1 Defining Carbon Footprints

Carbon footprint accounting can be carried out at a variety of levels (e.g., national, per person, product, service, etc.). Despite the high level of interest in carbon footprinting, there is a surprising lack of agreed upon definitions as to what a carbon footprint is. The Guide to PAS 2050 (BSI, 2008) suggests that: “The term ‘product carbon footprint’ refers to the greenhouse gas emissions of a product across its life cycle, from raw materials through production (or service provision), distribution, consumer use and disposal/recycling. It includes the greenhouse gases carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), together with families of gases including hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs)”. In this study we’ve used the Carbon Footprint as a measure of the total amount of GHG emissions that are directly and indirectly caused by an activity or are accumulated over the life stages of a product. This includes activities of individuals, populations, governments, companies, organizations, processes, industry sectors, etc. Products include goods and services. In any case, all direct (on-site, internal) and indirect emissions (off-site, external, embodied, upstream, and downstream) need to be taken into account.

Greenhouse gas emissions arise at every point in the life of a product. Emissions may be direct (from animals, fertilizer application, fuel use) or indirect (e.g., from electricity generation). Each GHG has a different potential to increase atmospheric temperature. To enable them to be discussed in a common language, characterization factors are applied to the gases against a standard radiative effect (the act of emitting or causing the emission of radiation). The characterization model for climate change, as developed by the Intergovernmental Panel on Climate Change (IPCC), contains a series of internationally recognized characterization factors. Factors are expressed as global warming potential (GWP) for a time horizon of 100 years (GWP100), in kg carbon dioxide equivalent (CO2 eq)/kg emission. For a calculation of lifetimes and a full list of greenhouse gases and their global warming potentials please refer to Solomon et al. (2007).

In this study, all emissions are viewed from a consumption perspective. This means that emissions associated with cultivating and transporting food destined for the UK but grown elsewhere are included, and in turn a proportion of emissions from UK agriculture are allocated to food exported from the UK, and these are not included herein. Several studies have highlighted that imports of all goods account for around a third of the UK/European greenhouse gas emissions from a consumption perspective (Wiedmann et al., 2008; Brinkley and Less, 2010; Davis and Caldeira, 2010).

Unlike a water footprint, there are no local or regional interpretations of the impact of carbon emissions; a kilogram of carbon dioxide emitted in one country contributes to climate change in the same way as a kilogram emitted elsewhere (Forster et al., 2007). In this document, the objective is to account for the total carbon footprint of food waste and visualize where most emissions occur.

We’ve assumed that the greenhouse gas emissions associated with growing the same crop in different countries remain constant. This is a significant limitation, as from studies by Mila i Canals et al. (2007) and others it is known that the emissions associated with growing a foodstuff vary by season and location. The use of single figures in this analysis does not allow for illustration of the varying emissions associated with wasting food at different times of the year or from different sources. There is a range of data gaps for different food products at present. In the short to medium term we anticipate that this will be filled through a wider adoption of product carbon footprinting using PAS 2050, the WRI/WBCSD GHG Protocol, and the upcoming ISO Standard on product carbon footprinting.

6.2.1 Carbon Footprint

Carbon footprints for different crops are very difficult to compare because the calculation is dependent on local yields and environmental conditions. Machado et al. (2017) compared the soil carbon loss for different crops using field trials in Brazil and found that soil carbon loss from cassava cultivation (14.5 ton/ha) was much higher than that of corn (4.7 ton/ha) and sugarcane (ton Mg/ha) but lower than that of sugar beets (14.5 ton/ha). It is estimated that GHG emissions from cassava-derived bioethanol produced in Malaysia could be between 58% and 72% lower compared to emissions from conventional gasoline use (Hanif et al., 2017; Numjuncharoen et al., 2015). Nguyen and Gheewala (2008) estimated that bioethanol produced from cassava in Thailand could lower GHG emissions by as much as 6%. Papong et al. (2017) compared the GHG emissions from cassava and sugarcane crops in Thailand and showed that when the entire value chain is taken into account both crops have approximately the same GHG emissions profile. The estimated GHG emissions associated with cassava-based ethanol from different countries is compared in Table 6.1.

Table 6.1. Comparison of Estimated GHG Emissions for Cassava-Based Bioethanol in Different Countries

n/a, Not reported.

When comparing the GHG emissions in Table 6.1 with the estimated GHG emissions of fossil-based petroleum (∼1800 gCO2eq/L fuel) most of the estimates of Cassava exceeds that of fossil fuel when GHG emissions associated with direct land use change (dLUC) and indirect land use change (iLUC) is taken into account in the life cycle assessment (LCA) (Machado et al., 2017). Nguyen et al. (2017) calculated that the CO2 emissions debt due to cassava dLUC would take 25 years to pay back if the ethanol yield per ha can be maintained at 33 ton/ha. A number of studies showed that using water effluent from the cassava processing and ethanol production plants for biogas production could lower the GHG emissions to below that of the equivalent fossil fuel (Zhang et al., 2017). Furthermore, coprocessing of cassava wastes and peels to ethanol could significantly increase the ethanol yield per ha, which would also reduce the GHG emissions associated with a cassava crop.

3.2 Carbon footprint “hotspots”

The CF “hotspots” vary for different crops (Litskas et al., 2019b). One of the most important CF “hotspots” for intensive agriculture is fertilizer use. Fertilizer production consumes high amounts of energy, resulting in substantial GHGEs (Hillier et al., 2012). In addition, fertilizer application leads to N2O emissions that derive from the transformations occurring in the nitrogen cycle in soils (Chadwick et al., 2011; Herrero et al., 2013; Hou et al., 2015) (Fig. 3.3).

Field energy use is another important CF “hotspot” (Fig. 3.3). Energy production and consumption (e.g., for tillage, irrigation, transportation) contributes substantially to GHGEs (Kaltsas et al., 2007; Kavargiris et al., 2009; Litskas et al., 2017; Michos et al., 2018). The assessment of energy use in agriculture is crucial, since it is mainly in a nonrenewable form (Kavargiris et al., 2009; Michos et al., 2017). The agricultural sector accounts for 5% of the total energy consumption in the world (IPCC, 2014). Energy use can be evaluated via an energy analysis of agricultural systems (Litskas et al., 2019b), an approach based on the conversion of all the production factors and crop products into energy units (Litskas et al., 2011, 2013; Michos et al., 2012, 2017, 2018).

Other important CF “hotspots” include residue management in the field, pesticide applications and transportation of the products to the market (Litskas et al., 2017, 2019b).

Besides management practices at farm scale, land use change and deforestation also contribute to substantial emissions. Almost 50% of the Agriculture, Forestry, and Other Land Use (AFOLU) emissions derive from land-use change and deforestation (IPCC, 2014).

14.2.2 Carbon footprint defined

The carbon footprint for food waste is defined as the amount of GHGs emitted during the production and treatment of the food waste equivalent to the radiative forcing exhibited by the unit CO2 emitted; the amount of GHGs is, thus, usually expressed in kilograms of CO2 equivalent (kg CO2 eq.). This includes the GHG emissions during the agricultural phase, from on-farm energy use and nonenergy-related emissions from soils and livestock. The most often evaluated GHGs, apart from CO2, are CH4, N2O, and halogenated gases for their significant contribution to the global warming effect either via significant amounts of emission or via a significantly higher radiative efficiency (the ability to retain heat or infrared radiation) (Myhre et al., 2013; Etminan et al., 2016). For food (waste) production and waste treatment, CH4 and N2O are the most relevant GHGs in addition to CO2 (discussed in more detail in Section 14.4.1). Thus, in this study, the carbon footprints are evaluated based on studies estimating these three types of gases unless otherwise specified.

Carbon footprint

Food's carbon footprint is the GHG emissions produced by growing, rearing, farming, processing, transporting, storing, cooking, and disposing of the food. Owing to increasing interest in environmental and sustainability issues, there is an increasing demand from consumers and private industries to reduce carbon or GHG emissions associated with food production. Hence, the market for sustainable products is expected to expand significantly in the future.

It is also no longer just environmentalists and policymakers who are concerned about GHG emissions but also food producers and retailers. For example, Walmart has announced plans to label each of its products with a sustainability rating and has subsequently requested that every Walmart supplier provide information about its GHG footprint, a direct measure of climate impact. Walmart has also developed their own ‘sustainability index,’ which they said will create a more transparent supply chain and drive product innovation.

8.3.8 Food Miles

The carbon footprint for food miles is calculated by multiplying the distance the food (or each food ingredient) has traveled by the carbon emission of the transportation type, airplane, truck, barge, or railroad. The distribution patterns of food in the United States have clearly changed since the days when 40% of Americans lived on farms and produced the majority of their own food. As discussed in Chapter 3, Innovations in US Agriculture, food production occurs in concentrated regions, with fewer but larger operations. More food is also imported from other countries. Distribution of foods from their site of production to consumers involves a complex network of handlers and modes of transport. Air transportation is by far the most energy-intensive method of food distribution and barge transport the lowest:

Airplane—10.0 MJ/km

Truck—2.7 MJ/km

Railroad—0.3 MJ/km

Barge—0.2 MJ/km

There are efficiencies of scale associated with larger food production systems that make them more economical, such as more mechanization to reduce labor costs, and higher volume generating more net income. There is a trade-off in these efficiencies by adding the costs, both economic and environmental, to distribute the product. The mode and volume of transportation of food defines the net environmental impact. Food transported by road contributes 60% of the world’s food transportation emissions because vans and trucks move smaller amounts of food, compared to railroads or barges. A smaller carbon footprint and less energy may be needed to deliver milk by bulk rail transport several hundred miles from a dairy to a distribution center, than for one consumer to drive 25 miles for 3 gallons of milk.

The purpose of “Buy Fresh Buy Local” (BFBL) initiatives is to reduce transportation miles and to support rural economies for the benefit of farmers and small town businesses. The sociological aspects of our current food system are very different than 50 years ago when more people were engaged in agriculture. Many consumers have lost connectedness with food production. The desire to regain this connection has fostered the buy local movement. Defining how buying local affects the environmental impact of farming is complicated. With an increased interest in local foods, there will be smaller deliveries made by more farmers. A consumer that drives to one large grocery store, once a week to purchase food will use less fuel than a consumer who drives to a farmer’s market for produce, a dairy farm for milk, and a butcher for chicken. In contrast, the net amount of energy needed to deliver all the food to the large grocery store is high, whereas the farmer has essentially no transportation costs for the food s/he produces.

Limiting foods to those that are grown or produced locally would have an impact on those living in temperate climates, which is most of the United States. There would be limited access and availability of tropical fruits such as oranges, bananas, kiwi, pineapple, and avocado. Consumption of fresh fruits and vegetables would be limited to the summer months or to preserved or greenhouse-grown products during the rest of the year. The cost of all foods would likely increase. Consumers have come to expect all fresh fruits and vegetables to be available during the entire year and seasonality is a concept of the past. Based on today’s economy and lifestyles, reliance on only foods produced locally cannot be achieved in most parts of the country. Quantifying these economic, social, and environmental impacts of food production and distribution will be needed to optimize the food system. It is not sufficient to simply assume a local food production model will correct the environmental impact without considering all aspects of the food system.

Chicken

The product carbon footprint of Quorn pieces can be considered to be at least four times lower than that of chicken. Data from FAO analysis (MacLeod et al., 2013) as well as PAS 2050-certified industry data for both United Kingdom and Irish systems, applied via methodology that takes account of the additional waste burden (eg, bones) that would derive a comparable edible meat yield footprint for comparison to Quorn—as opposed to published data referring only to carcass weight.

Therefore, it is clear that Quorn products may well have a significant role to play in addressing the challenges of our food system and its associated GHG impacts.

2.1 GHG emissions

The environmental impact can be quantified using carbon footprint, which is defined as a total measurement of total greenhouse gases which are methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), perfluorocarbon (PFC’s), sulfur hexafluoride (CF6), and hydroflurocarbons (HFC’s). In order to calculate the carbon footprint, the conversion factor is multiplied by the energy consumed (kWh). The energy conversion factors adopted from the Department of Environment, Food and Rural Affairs (2018) are shown in Table 1.

Table 1. Energy consumption factors (Anon, 2018).

For instance, the percentage differences in greenhouse emissions for dehydration of the food materials using electro-osmosis and thermal drying is shown in the following equation:

(1)Percentage difference=a−b /b×100

where a is the greenhouse emissions calculated from electro osmosis and b is the greenhouse emissions of thermal drying.

Global Food Wastage and Sustainability

As described above, the financial value of food makes it look like a cheap good, and agriculture as a whole is not a competitive sector in terms of attracting investments. Thus, consumers do not swiftly act on spoiling food, nor producers invest in improved infrastructure. The food wastage landscape would look very different if the environmental and social costs of food system became visible (FAO, 2014a).

It is with this intent that the Food and Agriculture Organization of the United Nations evaluated the impact of food wastage on carbon emission, water scarcity, land occupation and biodiversity, as well as the impact of environmental degradation on livelihoods, health and conflicts over natural resources.

Using data from the 2011 Food Balance Sheets, the carbon footprint1 of food produced and not eaten, including land use change, is 4.4 Gt CO2 e, or about 8% of global anthropogenic greenhouse gas emissions (FAO, 2015). This means that the contribution of food wastage emissions to global warming is almost equivalent (87%) to global road transport emissions; should food wastage be a country, it would rank as the third largest emitter after USA and China. The social cost of carbon emitted by food wastage amounts to roughly USD 411 billion per year, including damage costs and defensive expenditures related to climate change.

Reducing the carbon footprint of food wastage should focus on major hotspot commodities, such as meat and cereals (see Fig. 2). Rice emerges as high carbon intensity, as paddy fields emit a greenhouse gas with high warming potential such as methane (CH4). In addition to livestock operations, fisheries contribute relatively high greenhouse gas emissions through boats' diesel combustion, leakage of on-board refrigerants, production of fishmeal and other fish farm inputs and industrial aquaculture operations (e.g. bivalves in particular are important CH4 emitters) (FAO, 2015). Also, the highest carbon footprint of wastage occurs at the consumption phase, as carbon emissions add-up along the supply chain. On a global average, per capita food wastage footprint on climate in high income countries is more than double that of low income countries, due to wasteful food distribution and consumption patterns (FAO, 2013a).

Regarding the consumption of surface and groundwater resources, the water footprint of food wastage is about 250 km3 (FAO, 2013a), which is equivalent to the annual water discharge of the Volga River, or three times the volume of Lake Geneva. Again, cereal (especially rice and wheat in Asia) wastage emerges as a significant environmental hotspot, with major impacts on carbon, blue water and occupation of arable land (FAO, 2013a). India and China are the major contributors of the water footprint of cereals in their respective regions. However, higher yields for rice and wheat result in a lower water footprint and lower land occupation in industrial Asia, as less land is being used for the same level of production (FAO, 2013a). This echoes a broadly recognizable global pattern: high efficiency and high consumer level waste in middle- and high-income regions, versus lower production efficiency and lower consumer level waste in low-income regions. When accounting for water impact, crop water intensity must be considered in relation to water scarcity of the location where the food is produced. Increased water scarcity by food wastage, particularly for dry regions and seasons, is estimated to incur damage and defensive expenditures cost to society of USD 164 billion per year (FAO, 2014b).

Produced but uneaten food vainly occupies almost 1.4 billion hectares of land (FAO, 2013a); this represents 28% of the world's agricultural land area, an area as large as the Russian Federation. Land occupation intensity is highest with food wastage of meat and milk because land occupation by animals for housing and grazing is to be added to feed production areas. Thus, when considering livestock-related wastage impacts on land, their impact will depend on grassland productivity (large areas are required to feed livestock), as well as on the feed conversion efficiency of the animal, the composition of the feeding ration and the origin of the constituents of the ration. Across all regions of the world, surfaces of non-arable land occupied to produce lost/wasted milk and meat contribute to as much as 46%–85% of the total land occupation of food wastage in each region (FAO, 2013a). Furthermore, land occupied to grow food can have different degradation levels; more than 50% of food wastage at agricultural production stage appears to be produced in regions whose soils are somewhat degraded, thus adding pressure unduly. Land occupation (and related loss of ecosystem services and deforestation) and soil erosion by water are estimated to cost USD 35 billion per year through nutrient loss, lower yields, biological losses and off-site damages (FAO, 2014b). The cost of wind erosion may be of a similar magnitude.

While it is difficult to estimate impacts on biodiversity at a global level, food wastage unduly compounds the negative externalities that mono-cropping and agriculture expansion into wild areas create on biodiversity loss, including mammals, birds, fish and amphibians. Overall, agriculture is responsible for 66% of threats to species but there is considerable regional variability, since agriculture causes only 23% of threats to species in New Zealand, but up to 90% of threats in Mongolia (FAO, 2013a). Cereal production is a main cause of food wastage in most regions, probably constituting the main threat to biodiversity, both in terms of deforestation and species' threats. This is due to the large extents of land that need to be converted for their production, usually leading to simplification and degradation of habitats. Food wastage costs to biodiversity, including just a few categories of quantifiable impacts, such as impacts of pesticide use, nitrate and phosphorus eutrophication, pollinator losses and fisheries overexploitation, are estimated to cost USD 32 billion per year (FAO, 2014b). Biodiversity impacts are largely underestimated, due to both data gaps and methodological limitations. For example, global fish wastage by commercial fisheries is estimated to USD 10 billion/year; this does not include recreational fisheries, marine tourism and illegal fishing, nor fish processing, distribution and consumption, or the value of extinct species or compromised ocean food chains and carbon cycles (FAO, 2014b).

In total, the monetizable cost to society of environmental damage and defensive expenditures incurred by food wastage was estimated in 2013 to be approximately USD 700 billion per year (FAO, 2014b). In addition, direct social wellbeing loss and acute health treatment costs inflicted by environmental degradation include: (i) increased risk of conflict due to soil erosion, estimated to cost USD 396 billion per year (for the 2005–8 period) (ii) loss of livelihoods (i.e. food security risk and loss of income); due to soil erosion, estimated to cost USD 333 billion per year; and adverse health effects (toxicity) due to pesticide exposure in drinking water, estimated to cost USD 153 billion per year (for adults over 18 years of age only) (FAO, 2014b). These total social costs of USD 900 billion per year represent only a minor part of the real social cost of food squandering.

According to these incomplete estimations of impacts, the magnitude of the economic (including both food prices and wasted OECD subsidies), environmental and social costs of food wastage totals USD 2.6 trillion annually, roughly equivalent to the GDP of France, or approximately twice total annual food expenditure in the USA. Fig. 3 depicts a more comprehensive framework of direct and indirect impacts of food wastage.

Unveiling the hidden costs of food wastage strongly justifies wastage mitigation efforts. What is revealed is that it is not cheaper to let food spoil in the fields and processing lines, on the market shelves, in food services, or in household fridges. Actually, a careful analysis of full costs and benefits may flip the argument on its head, as benefits may be accrued beyond expectation.