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Please use this identifier to cite or link to this item: http://dspace.lib.cranfield.ac.uk/handle/1826/6503

Document Type: Report
Title: How low can we go? An assessment of greenhouse gas emissions from the UK food system and the scope reduction by 2050. Report for the WWF and Food Climate Research Network
Authors: Audsley, Eric
Brander, M.
Chatterton, Julia C.
Murphy-Bokern, Donal
Webster, C.
Williams, Adrian G.
Issue Date: 2010
Citation: Audsley, E., Brander, M., Chatterton, J., Murphy-Bokern, D., Webster, C., and Williams, A. (2009). How low can we go? An assessment of greenhouse gas emissions from the UK food system and the scope to reduce them by 2050. WWF-UK.
Abstract: Summary The overall aim of this study was to develop a set of scenarios that explore how greenhouse gas emissions from the UK food system may be reduced by 70% by the year 2050. The work is focused on all emissions from the supply chains and systems, not just the emissions from the UK food chain that arise in the UK. The study comprises an audit of the greenhouse gas emissions arising from the UK food economy and an examination of the scope for substantial reductions of these emissions. The aim of this short and preliminary study conducted over a few months in 2009 is to stimulate debate about the full GHG impact of the UK food chain and the scope and options for reducing GHG emissions in line with wider climate change policy. The study is theoretical, in effect a thought experiment based on detailed inventories of emissions and the use of life cycle assessment (LCA) to examine the effects of measures. As far as we are aware, this is the first study to identify systematically the proportion of global land use change attributable to commercial agriculture linked to international trade. From this it estimates a proportion of global land use change emissions attributable to the UK food supply chain. In considering this report, especially the scenarios for reductions, it is important to appreciate that we are not presenting a model or components of a model for working out the full effect of policy choices. This report identifies the size and sources of present emissions and identifies scenarios from these for reductions. Our scenarios set out possible directions of travel but we emphasise that the full real-world effect of greenhouse gas mitigation strategies will depend on the consequences of complex interactions that cannot be predicted here. Measures may open up opportunities for synergies in specific circumstances that will be revealed in the path to a low carbon food system giving additional benefits. Similarly, there are also risks that some measures may trigger economic responses with unintended consequences - for example a reduction in demand for ruminant products may cause the widespread abandonment of UK grazing land leading to increased imports from sources closer to active land use change. Our estimates are based on the current UK population. This is expected to increase substantially by 2050. There will be a corresponding increase in food system emissions as the food economy grows. But from a global perspective, this is a growth in GHG emissions that will occur somewhere as the global population expands. By working on the basis of food system emissions in 2005, we have avoided confusion between the effectiveness of measures and trends in population. We also want to emphasise that our study is about the food system and therefore does not consider other agricultural land uses - for example for biofuels. However, our findings are applicable to the assessment of other uses of agricultural products. Our main results are as follows: Using a detailed inventory of emissions developed from LCA of a wide range of foods and processes, we estimate that the supply of food and drink for the UK results in a direct emission equivalent of 152MtCO2. A further 101 MtCO2e from land use change is attributable to UK food. Total UK consumption emissions are estimated to be about 748MtCO2e (excluding land use change).[1] This means that direct emissions from the UK food system are about 20% of the currently estimated consumption emissions. When our estimate of land use change emissions is added to these, this rises to 30%. In our work, we refer to direct emissions (excluding land use change emissions) as ‘supply chain emissions'. Of these, about 58% arise from animal products which account for just over 30% of consumer energy intake. Two thirds of food production emissions arise in the UK, 16% arise outside Europe. Overall, about one fifth of direct UK food chain emissions occur outside the UK. If land use change emissions are taken into account, then about a half of total food system emissions arise outside the UK. So our results indicate that the food system in particular presents special challenges for climate change policy focused on domestic emissions and targets. Taking the food chain as a whole, the supply chain emissions comprise (on a CO2 equivalent basis) CO2 - 102 Mt, CH4 - 23 Mt, N2O - 21 Mt and refrigerants - 6 Mt. Fifty-six per cent of emissions arise from primary production (mainly farming) with CH4 and N2O accounting for more than half of these. Land use change (mainly deforestation) driven by agricultural expansion is a hugely important source of emissions attributable to the global food system. The UK food system is part of the global food system contributing to the underlying forces. We estimate that global land use change emissions account for 40% of the emissions embedded in UK consumed food and 12% of emissions embedded in all UK consumption overall. This is based on the allocation of 2.1% of global land use change emissions to the UK food supply chain. This estimate is based on global average yields and land use. Managed and native grassland covers more land than arable crops. As a result, a large proportion (around three quarters) of LUC emissions is allocated to ruminant meat. We used alternative ways of allocating emissions which increase allocations to crops and reduce allocations to pasture, for example by allocating according to the economic value of crop and livestock farm outputs. This reduced emissions from beef and sheep/goat meat production from 77 Mt CO2e to 42 Mt CO2e out of a total of 102 and 86 Mt CO2e respectively. So while allocation on economic value reduces the emissions attributable to beef and sheep meat, we are confident that the broad conclusions remain across the various allocation methods that could be used. By assessing and attributing a proportion of land use change emissions to agricultural land use generally, our analysis draws attention to how consumers share responsibility directly or indirectly for the drivers behind land use change. We work on the premise that commodity markets are highly connected. Our analysis could lead to the conclusion that transferring consumption away from products directly linked to land use change to products from established farmland through product certification may displace rather than reduce the underlying pressures. This highlights the need for demand/market based approaches (e.g. product certification and moratoria) that counter the economic forces driving land use change, complementing ‘top-down' government measures that seek to stop deforestation directly. The supply chain measures we examined to achieve a 70% reduction in supply chain emissions range from the decarbonisation of energy carriers used in food production and measures to increase farm efficiency to technologies to reduce emissions of methane. Our results confirm that significant reductions will involve radical structural change throughout the supply chain from the generation of electricity through to the preparation of food. No single measure or the combination of similar measures is capable of reducing emissions by more than about half. The decarbonisation of the wider economy sought now by government policy by 2050 will reduce food supply chain emissions by about 50%. A vegetarian diet (with dairy and eggs), a 66% reduction in livestock product consumption, and the adoption of technology to reduce nitrous oxide emissions from soils and methane from ruminants are measures that each have the potential to reduce direct supply chain emissions by 15-20%. Modifying consumption has a particularly important role to play and consumption measures offer opportunities for reductions that could be implemented in the near future. In addition, consumption measures align with other public policies, particularly health. A switch from red to white meat will reduce supply chain emissions by 9% but this would increase our reliance on imported soy meal substantially. Our analysis indicates that the effect of a reduction in livestock product consumption on arable land use (which is a critical component of the link with deforestation) will depend on how consumers compensate for lower intakes of meat, eggs and dairy products. A switch from beef and milk to highly refined livestock product analogues such as tofu and Quorn could actually increase the quantity of arable land needed to supply the UK. In contrast, a broad-based switch to plant based products through simply increasing the intake of cereals and vegetables is more sustainable. We estimate that a 50% reduction in livestock production consumption would release about 1.6 Mha of arable land (based on the yield of crops supplying the UK) used for livestock feed production. This would be offset by an increase of about 1.0 Mha in arable land needed for direct crop consumption (based on UK yields). In addition to the release of arable land, between 5 and 10 Mha of permanent grassland would be available for extensification, other uses, or re-wilding. Such changes would open up ‘game-changing' opportunities but there needs to be careful assessment made in the development policy if unintended consequences are to be avoided. A contraction in the livestock sector that might follow a significant change in consumption could trigger a collapse of livestock production in the UK. The consequences for the emissions from the UK food chain would then depend on developments elsewhere. Completely unregulated, such a collapse could reinforce expansion in low cost exporting countries, even adding to forces driving land use change. Our examination of measures that raise production and nitrogen use efficiency indicates that this approach has the potential for savings that are less than consumption based measures. This is supported by the scientific literature. However we acknowledge and set out evidence from elsewhere that this too has an important role to play. We anticipate too that there are potential synergies between production efficiency measures and consumption measures that we have not been able to simulate - for example a reduction in livestock product consumption may synergise with efforts to raise the efficiency of nitrogen use in the food system. There are also possible synergies between efforts to raise production efficiency and the use of technologies to reduce emissions directly. Consumption based measures would mean a significant contraction in livestock production for UK consumption and this opens up opportunities to restructure agriculture in a way that enhances the benefits of production efficiency measures. In addition, from a global perspective, reductions in livestock consumption and measures to increase production efficiency synergise with efforts to eliminate deforestation. Improving production efficiency and reducing production emissions directly will mean embracing new technologies. These need to be carefully applied to whole systems to raise system eco-efficiency. Our analysis indicates there is little scope for emission reductions through the exclusion of production technologies - for example through the widespread adoption of organic farming. We estimate from analysis of recently published work that a complete conversion to organic farming in the UK with corresponding changes in diet would reduce supply chain emissions by about 5%. Emissions from fish consumption were quantified, but expansion in fish production to replace other livestock products was not considered owing to concerns about the sustainability of wild fish stocks. This though has significant potential depending on the success of developing new aquaculture systems. Very significant change in the food system is required to achieve a 70% reduction in supply chain emissions. The consumption and farm technology changes align with other policy objectives, for example public health, nitrate emissions, ammonia emissions and biodiversity. The scenarios set out here do not have definitive implications for animal welfare outcomes in one direction or another. The reduction in animal products consumption generally as set out in consumption measures opens up opportunities to improve welfare. However, measures to increase production efficiency at the animal level raise questions about the welfare consequences. This underscores the importance of whole system analyses and an emphasis on whole system solutions rather than just on interventions at the individual animal level. Our results also show that a 70% reduction in supply chain emissions (i.e. excluding land use impact) may be possible without significant changes in consumption. However, if repeated across the developed and developing world, such a high level of livestock product consumption would require a large expansion in global agriculture and would make contraction and convergence of emissions difficult. Per-capita UK meat consumption is more than twice the world average, and nearly three times that of developing countries. As the global food system becomes more resource constrained and developing countries lift themselves out of poverty, consumption based measures will acquire relevance beyond just the UK's greenhouse gas emissions. [1] Garnett, T. 2008. Cooking up a storm. Food, greenhouse gas emissions and our changing climate. The Food and Climate Research Ne
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