CERES :: Browsing by Author "Williams, Adrian G."

Browsing by Author "Williams, Adrian G."

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Open Access
Addressing crop interactions within cropping systems in LCA
(Springer, 2017-09-08) Goglio, Pietro; Brankatschk, Gerhard; Trydeman Knudsen, Marie; Williams, Adrian G.; Nemecek, Thomas
Purpose The focus of the Life Cycle Assessment (LCA) of an agricultural plant product is typically on one crop. However, isolating one crop from the cropping system that it belongs to is often challenging because the crops are often interlinked with the other crops in the cropping system. The main objectives of this discussion article are: i) to discuss the characteristics of cropping systems which might affect the LCA methodology, ii) to discuss the advantages and the disadvantages of the current available methods for the life cycle assessment of cropping systems and iii) to offer a framework to carry out LCA of crops and cropping systems. Methods The definition of cropping systems is provided together with a description of two types of LCA: product LCA and system LCA. The LCA issues related to cropping systems characteristics have been classified as 1) crop interrelationship, 2) crop management and emissions, and 3) functional unit issues. The LCA approaches presented are: Cropping System, Allocation approaches, Crop-by-Crop approach, Combined approaches. The various approaches are described together with their advantages and disadvantages, applicability, comprehensiveness and accuracy. Results and discussion The Cropping System approach is best suited for system LCA. For product LCA, none of the methods is fully exhaustive and accurate. The crop sequence approach takes into consideration cropping systems issues if they happen within the year or season and cannot be applied for intercropping and agroforestry systems. The allocation approaches take into consideration cropping system effects by establishing a mathematical relationship between crops present in the cropping systems. The Model for integrative Life Cycle Assessment in Agriculture (MiLA) approach considers cropping systems issues if they are related to multiproduct and nutrient cycling; while the Crop-by-Crop approach is highly affected by assumptions and considers cropping system issues only if they are related to the analysed crop. Conclusions Each LCA approach presents advantages and disadvantages. For system LCA, the Cropping Systems approach is recommended. For product LCA, environmental burdens should be attributed applying the following hierarchy: 1) attributed to the crop if based on a clear causality; 2) attributed with combined approaches and specific criteria; 3) attributed with allocation approaches and generic criteria. These approaches should be combined with the Cropping System approach.
Open Access
Advances and challenges of life cycle assessment (LCA) of greenhouse gas removal technologies to fight climate changes
(Elsevier, 2019-10-14) Goglio, Pietro; Williams, Adrian G.; Balta-Ozkan, Nazmiye; Harris, Neil R. P.; Williamson, Phillip C.; Huisingh, Donald; Zhang, Zhe; Tavoni, Massimo
Several greenhouse gas removal technologies (GGRTs), also called negative emissions technologies (NET) have been proposed to help meet the Paris Climate Agreement targets. However, there are many uncertainties in the estimation of their effective greenhouse gas (GHG) removal potentials, caused by their different levels of technological development. Life Cycle Assessment (LCA) has been proposed as one effective methodology to holistically assess the potential of different GGRT removal approaches but no common framework is currently available for benchmarking and policy development. In this article, challenges for LCA are reviewed and discussed together with some alternative approaches for assessment of GGRTs. In particular, GGRTs pose challenges with regards to the functional unit, the system boundary of the LCA assessment, and the timing of emissions. The need to account within LCA of GGRTs for broader implications which involve environmental impacts, economic, social and political drivers is highlighted. A set of recommendations for LCA of GGRTs are proposed for a better assessment of the GGRTs and better accounting of their carbon removal potentials to meet the targets established within the Paris Agreement.
Open Access
Analysis of the 2007/8 Defra Farm Business Survey Energy Module
(2010-11-30T00:00:00Z) Williams, Adrian G.; Pearn, Kerry R.; Sandars, Daniel L.; Audsley, Eric; Parsons, David J.; Chatterton, Julia C.
Key points This study has delivered an invaluable baseline estimate of energy use and greenhouse gas (GHG) emissions on commercial farms in England. Energy use and GHG emissions associated with particular commodities were quantified and results broadly agreed with those derived by Life Cycle Assessment, but with much scatter in the environmental performance of farms.Direct energy use on farms was generally less that indirect (embedded) energy use, except for horticulture, which is dominated by heating fuel use. In contrast, most GHG emissions are incurred on farms, rather than as embedded emissions.Scatter in both environmental and economic performance underlies the somewhat disappointing finding of no clear positive link between farm financial performance and energy use or GHG emissions. However, the mere existence of these ranges shows that there is scope for improvement in both financial and environmental performance and that there is no apparent barrier for both to be achievable in harmony. The recording of such farm-level energy data is essential for the future, as it should enable improvements to be made in efficiency of energy use. The improved UK agricultural GHG inventory will depend on high quality energy data on agricultural activities. This study will be invaluable in identifying the level of detail needed. Future data requirements include: contractor work rates and fuel use per unit area and per unit time, fertiliser and pesticide use by brand name, enhanced output data, especially animal live weights, and horticultural produce recorded by weight rather than by value.
Open Access
Assessing the carbon capture potential of a reforestation project
(Nature Publishing Group, 2021-10-07) Lefebvre, David; Williams, Adrian G.; Kirk, Guy J. D.; Burgess, Paul J.; Meersmans, Jeroen; Silman, Miles R.; Román-Dañobeytia, Francisco; Farfan, Jhon; Smith, Pete
The number of reforestation projects worldwide is increasing. In many cases funding is obtained through the claimed carbon capture of the trees, presented as immediate and durable, whereas reforested plots need time and maintenance to realise their carbon capture potential. Further, claims usually overlook the environmental costs of natural or anthropogenic disturbances during the forest’s lifetime, and greenhouse gas (GHG) emissions associated with the reforestation are not allowed for. This study uses life cycle assessment to quantify the carbon footprint of setting up a reforestation plot in the Peruvian Amazon. In parallel, we combine a soil carbon model with an above- and below-ground plant carbon model to predict the increase in carbon stocks after planting. We compare our results with the carbon capture claims made by a reforestation platform. Our results show major errors in carbon accounting in reforestation projects if they (1) ignore the time needed for trees to reach their carbon capture potential; (2) ignore the GHG emissions involved in setting up a plot; (3) report the carbon capture potential per tree planted, thereby ignoring limitations at the forest ecosystem level; or (4) under-estimate tree losses due to inevitable human and climatic disturbances. Further, we show that applications of biochar during reforestation can partially compensate for project emissions.
Open Access
Assessing the impact of greenhouse gas emissions on economic profitability of arable, forestry, and silvoarable systems
(MDPI, 2021-03-25) Kaske, Kristina J.; García de Jalón, Silvestre; Williams, Adrian G.; Graves, Anil R.
This study assesses the greenhouse gas (GHG) emissions and sequestration of a silvoarable system with poplar trees and a crop rotation of wheat, barley, and oilseed rape and compares this with a rotation of the same arable crops and a poplar plantation. The Farm-SAFE model, a financial model of arable, forestry, and silvoarable systems, was modified to account for life-cycle greenhouse gas emissions. Greenhouse gas emissions from tree and crop management were determined from life-cycle inventories and carbon storage benefits from the Yield-SAFE model, which predicts crop and tree yields in arable, forestry, and silvoarable systems. An experimental site in Silsoe in southern England served as a case study. The results showed that the arable system was the most financially profitable system, followed by the silvoarable and then the forestry systems, with equivalent annual values of EUR 560, 450 and 140 ha−1, respectively. When the positive and negative externalities of GHG sequestration and emissions were converted into carbon equivalents and given an economic value, the profitability of the arable systems was altered relative to the forestry and silvoarable systems, although in the analysis, the exact impact depended on the value given to GHG emissions. Market values for carbon resulted in the arable system remaining the most profitable system, albeit at a reduced level. Time series values for carbon proposed by the UK government resulted in forestry being the most profitable system. Hence, the relative benefit of the three systems was highly sensitive to the value that carbon was given in the analysis. This in turn is dependent on the perspective that is given to the analysis.
Open Access
Comparing the environmental impacts of alternative protein crops in poultry diets: The consequences of uncertainty
(Elsevier Science B.V., Amsterdam., 2013-10-31T00:00:00Z) Leinonen, Ilkka; Williams, Adrian G.; Waller, Anthony H.; Kyriazakis, Ilias
The statistical significance of the effects of including different protein sources in poultry diets on the environmental impacts Global Warming Potential (GWP), Eutrophication Potential (EP) and Acidification Potential (AP) of typical UK broiler meat and egg production systems was quantified using the Life Cycle Assessment (LCA) method combined with an uncertainty analysis. The broiler and layer diets compared in the study were either standard soya-based, or alternative diets based on European-grown protein crops, including field beans, field peas, sunflower meal and whole rapeseed. Different methods for accounting for land use change (LUC) in feed crop production were applied, including (1) a weighted average of "new" and "mature" agricultural land used for soya production ("best estimate" scenario), (2) assuming no LUC in the production of soya used in these diets ("sustainable soya" scenario) and (3) including indirect LUC for all arable crop production ("top-down" scenario). Monte Carlo simulations were used to quantify uncertainties in predicted impacts and to perform statistical comparisons between the effects of different diet compositions. The results showed that when included at relatively high levels in the diets (10-30% by mass), peas, beans and rapeseed could slightly reduce the simulated mean value of GWP (up to 12%) of broiler meat and egg production. However, when uncertainties in the data were taken into account, these reductions were not statistically significant. Furthermore, the reduction in GWP strongly depended on the method of LUC accounting applied in the analysis. With the "sustainable soya" and "top-down" scenarios, only small, non-significant differences between the different diets were found. In the case of EP, only small non-significant changes could be achieved with the alternative protein sources. For AP, a significant reduction of more than 20% could be achieved if the crude protein content of the broiler diet was reduced by using peas in combination with pure amino acids. This study demonstrates the importance of a holistic approach, coupled with Monte Carlo uncertainty analysis, to evaluate the environmental impacts of livestock systems. It takes into account the environmental burdens related, for example, to feed production and transport and differences in emissions from housing and the end use of the manure. Furthermore, due to the systematic uncertainty analysis, the statistical significance of the effects of different feeding scenarios can now be evaluated.
Open Access
A comparison of methods to quantify greenhouse gas emissions of cropping systems in LCA
(Elsevier, 2017-03-23) Goglio, Pietro; Smith, Ward N.; Grant, B. B.; Desjardins, R. L.; Gao, X.; Hanis, K.; Tenuta, M.; Campbell, C. A.; McConkey, B. G.; Nemecek, Thomas; Burgess, Paul J.; Williams, Adrian G.
Carbon dioxide and nitrous oxide are two important greenhouse gases (GHG) released from cropping systems. Their emissions can vary substantially with climate, soil, and crop management. While different methods are available to account for GHG emissions in life cycle assessments (LCA) of crop production, there are no standard procedures. In this study, the objectives were: (i) to compare several methods of estimating CO2 and N2O emissions for a LCA of cropping systems and (ii) to estimate the relative contribution of soil GHG emissions to the overall global warming potential (GWP) using results from a field experiment located in Manitoba, Canada. The methods were: (A) measurements; (B) Tier I and (C) Tier II IPCC (Intergovernmental panel on Climate Change) methodology, (D) a simple carbon model combined with Intergovernmental Panel for Climate Change (IPCC) Tier II methodology for soil N2O emissions, and (E) the DNDC (DeNitrification DeComposition) agroecosystem model. The estimated GWPs (−7.2–17 Mg CO2eq ha−1 y−1; −80 to 600 kg CO2eq GJ−1 y−1) were similar to previous results in North America and no statistical difference was found between GWP based on methods D and E and GWP based on observations. The five methods gave estimates of soil CO2 emissions that were not statistically different from each other, whereas for N2O emissions only DNDC estimates were similar to observations. Across crop types, all methods gave comparable CO2 and N2O emission estimates for perennial and legume crops, but only DNDC gave similar results with respect to observations for both annual and cereal crops. Whilst the results should be confirmed for other locations, the agroecosystem model and method D can be used, at certainly one selected site, in place of observations for estimating GHGs in agricultural LCA.
Open Access
Energy and the food system
(Royal Society; 1999, 2010-09-01T00:00:00Z) Woods, J.; Williams, Adrian G.; Hughes, J. K.; Black, M.; Murphy, R.
Modern agriculture is heavily dependent on fossil resources. Both direct energy use for crop management and indirect energy use for fertilizers, pesticides and machinery production have contributed to the major increases in food production seen since the 1960s. However, the relationship between energy inputs and yields is not linear. Low-energy inputs can lead to lower yields and perversely to higher energy demands per tonne of harvested product. At the other extreme, increasing energy inputs can lead to ever-smaller yield gains. Although fossil fuels remain the dominant source of energy for agriculture, the mix of fuels used differs owing to the different fertilization and cultivation requirements of individual crops. Nitrogen fertilizer production uses large amounts of natural gas and some coal, and can account for more than 50 per cent of total energy use in commercial agriculture. Oil accounts for between 30 and 75 per cent of energy inputs of UK agriculture, depending on the cropping system. While agriculture remains dependent on fossil sources of energy, food prices will couple to fossil energy prices and food production will remain a significant contributor to anthropogenic greenhouse gas emissions. Technological developments, changes in crop management, and renewable energy will all play important roles in increasing the energy efficiency of agriculture and reducing its reliance of fossil resources. Keywords: energy in agriculture; fossil energy; agricultural greenhouse gas emissions; land use; agroforestry; policy
Open Access
Environmental burdens of producing bread wheat, oilseed rape and potatoes in England and Wales using simulation and system modelling
(Ecomed Publishers, 2010-12-31T00:00:00Z) Williams, Adrian G.; Audsley, Eric; Sandars, Daniel L.
Background, aims and scope Food production is essential to life. Modern farming uses considerable resources to produce arable crops. Analysing the environmental burdens of alternative crop production methods is a vital tool for policymakers. The paper describes the production burdens (calculated by life cycle analysis) of three key arable crops: bread wheat, oilseed rape and potatoes as grown in England and Wales using organic and non-organic (contemporary conventional) systems. Resource use (e.g. abiotic and energy) and burdens from emissions are included (e.g. global warming potential on a 100-year basis, global warming potential (GWP), and eutrophication and acidification potentials). Methods Crop production was analysed, using systems models, so that the effects of factors like changing N fertiliser application rates or irrigation could be examined. Emissions of nitrate were derived from a simulation model in which soil organic N was driven to steady state so that all long-term effects were properly accounted for. Yield response curves to N were similarly derived from long-term experiments. Crop nutrient inputs and plant protection applications were derived from national survey data and the literature. All major inputs were accounted for including fertiliser extraction, manufacture and delivery; pesticide manufacture; field fuel use; machinery and building manufacture; crop drying, cooling and storage. The current balance of production systems were found from survey data. The weighted mean national production was calculated froma combination of three rainfall levels and soil textures. The system boundary is the farm gate. The functional unit is 1 t marketable fresh weight of each product. Results and discussion The primary energy needs for the producing the three main crops were 2.4, 4.9 and 1.4 GJ/t for bread wheat, oilseed rape and potatoes, respectively. When expressed in terms of dry matter, protein or energy, wheat incurred smaller burdens than oilseed rape, which incurred lower burdens than potatoes. The crops do, of course, all play different roles. Organically produced bread wheat needed about 80% of the energy of non-organic, while organic potatoes needed 13% more energy than nonorganically produced ones. While pesticide use was always lower in organic production, other burdens were generally inconsistently higher or lower. Land occupation was always higher for organic production. Lower fertiliser use (and hence energy use) in organic systems is offset by more energy for fieldwork and lower yields. Main crop potato energy needs are dominated by cold storage. Reducing the N application rate for bread wheat production reduces energy use and GWP. The optimum for energy is with N at about 70% of the current level. It seems to be lower for GWP, but the sub-models used are beyond their range of reliability. The results are generally of the same order as those from other European studies. Conclusions Arable crop production depends heavily on fossil fuel in current major production systems. The emissions causing GWP are very dependent on nitrous oxide, more so than fuel consumption. That, together with emissions of ammonia and nitrate, means that agriculture has a C-N footprint rather than the C footprint that typifies most industrial life. Recommendations and perspectives With the large influence of nitrous oxide on GWP, evaluation of nitrous oxide emissions by another method, e.g. crop-soil simulation modelling instead of the more rigid IPCC method would improve the robustness of the analysis. The transition betweenfarming systems was not included in this study, but there could be short to medium term benefits of converting from nonorganic to organic methods that should be evaluated. System modelling allows alternative production methods to be readily explored and this greatly enhances LCA methodology.
Open Access
Estimation of the greenhouse gas emissions from agricultural pesticide manufacture and use.
(2009-08-01T00:00:00Z) Audsley, Eric; Stacey, K. F.; Parsons, David J.; Williams, Adrian G.
All references to energy for pesticide production in agriculture can be traced back to the original data of Green (1987). The most common method used to derive values for current chemicals is to use the average of each category of active ingredient. However a comparison of the mean and standard deviation of the categories provides little justification for using anything other than the overall average for agrochemicals, both for the total energy used and the breakdown into the different sources of inherent and process energy. However it is likely that using energy requirements derived directly from Green, such as the mean or maximum will generally underestimate for chemicals introduced since 1985.
Open Access
Food, land and greenhouse gases The effect of changes in UK food consumption on land requirements and greenhouse gas emissions. Report for the Committee on Climate Change.
(2010-12-21T00:00:00Z) Audsley, Eric; Angus, Andrew; Chatterton, Julia C.; Graves, Anil R.; Morris, Joe; Murphy-Bokern, Donal; Pearn, Kerry R.; Sandars, Daniel L.; Williams, Adrian G.
EXECUTIVE SUMMARY •1. Key findingsThis study examines the land use and greenhouse gas implications of UK food consumption change away from carbon intensive products. It shows that the UK agricultural land base can support increased consumption of plant-based products arising from the reduced consumption of livestock products. A 50% reduction in livestock product consumption reduces the area of arable and grassland required to supply UK food, both in the UK and overseas. It also reduces emissions of greenhouse gases from primary production by 19%. A switch from beef or sheepmeat (red meat) to pork or poultry (white meat) reduces food consumption related greenhouse gas emissions and the land area required but increases overseas arable land use. With this exception, the release of arable land now used to grow animal feed exceeds the additional arable land required for increased plant based foods in both the UK and overseas. Reducing livestock product consumption also has the potential to enable delivery of other significant environmental benefits, for example, reductions in ammonia and nitrate emissions. A 50% reduction in livestock product consumption reduces UK grassland needs for UK food production by several million hectares. This land could be used to supply livestock products for export markets although our scenarios assume that the proportions of imports, domestic production and exports remain constant. In these circumstances, some of the grassland released could be used to produce arable crops, including crops for biofuel production. Almost all of it could be converted to woodland or managed in other ways for biodiversity and/or amenity purposes. Conversion of this land resource to woodland has significant potential to increase soil carbon storage while supplying biomass for energy. Scenario Cropped area required, kha Grassland area required, kha Total area, kha Greenhouse gas emissions, kt CO2e/ year * UK OS Total UK OS Total UK OS Total Baseline 3,388 4,458 7,846 11,228 1,944 13,172 21,018 51,693 29,001 80,694 50% reduction in livestock with land release priority: Uniform 3,123 4,131 7,254 4,161 700 4,861 12,115 36,282 29,456 65,738 Maximise non-tillable land release 3,123 4,131 7,254 2,905 700 3,605 10,859 36,246 29,451 65,697 Maximise release of tillable land 3,123 4,131 7,254 7,102 700 7,802 15,056 36,282 29,457 65,739 Red to white meat with land release priority: Uniform 3,443 4,908 8,351 3,879 486 4,365 12,716 45,812 27,575 73,387 Maximise release of non-tillable land 3,443 4,909 8,352 2,909 486 3,395 11,747 45,867 27,572 73,439 Maximise release of tillable land 3,443 4,908 8,351 6,947 486 7,433 15,784 45,878 27,575 73,453 50% reduction in white meat consumption: Uniform 3,201 3,735 6,936 11,228 1,944 13,172 20,108 49,525 28,500 78,025 * The greenhouse gas emissions do not include possible effects of land use changeSummary table. The area of land needed to supply UK food and the greenhouse gas emissions from food production under current circumstances and under the seven scenarios studied. In a reduction scenario, concentrating remaining livestock production on different land types (e.g. concentrating on intensive production on lowland farms versus extensive production on lower quality land) has little effect on greenhouse gas emissions from primary production. This indicates that there is relatively little scope to reduce emissions by restructuring production (at least restructuring in relation to land use). It is further noted that concentrating livestock production on higher quality land would cause an almost complete closure of production for UK markets on land not suited to intensive grass or arable production, with biodiversity and economic impacts (discussed further below). The risks of unintended consequences with respect to greenhouse gas emissions are relatively low given the assumptions in the scenarios, but the actuality of such change will depend on future economic, social and political drivers. The report includes detailed analyses of land use and emissions data together with extensive discussion of a wide range of effects based on literature analysis. •2. Study objectivesThis study was conducted for the UK Government's Committee on Climate Change (CCC) to examine if UK agriculture can support consumption change away from carbon- intensive food products. For the purposes of the consumption scenarios, it is assumed the relationships between imports, exports and domestic consumption remain constant for each of the commodities used by the UK food system. The following questions were addressed: 1. Land needs: Given land quality considerations (e.g. land capability and constraints), to what extent is it possible to support a change in the UK consumption of meat and dairy products with a corresponding increase in substitute goods from UK agricultural land? Can a reduction in meat and dairy product consumption release land for other purposes? To what use would this freed-up land be suitable (e.g. food production, biomass production, carbon sequestration, other ecosystem service provision, forestry, etc.)? 2. Greenhouse gas emissions: What are the implications of the transition in production for GHGs both in the UK and abroad (including soil carbon releases, sequestration, reduced production of feed, etc, as well as reductions in direct N2O and CH4 emissions? 3. Other effects: What are the other implications, including for water, other pollutants, farm incomes, availability of manure as a fertiliser input, public health, ecosystem services, biodiversity, and animal welfare? 4. International implications: If UK agricultural land cannot support consumption changes, what are the international implications in terms of agricultural production and land-use displacement (e.g. deforestation, land for biofuels, land for food), and GHGs?•3. MethodsWe developed and used a combination of consumption and production scenarios to examine potential consequences of change. Life-cycle assessment (mainly life cycle inventory analysis) was applied to these scenarios to examine the overall effects of the consumption change on GHG and other emissions from primary production, in the UK and overseas. The production under the various scenarios was allocated to agricultural land resources by a combination of survey-based data analysis and model-derived calculations. Land use change (LUC) emissions (from changing soil C and biomass stocks) were calculated from data in the UK national inventory as well as from the UK Renewable Fuel Agency for overseas land types. Commodity flows as affected by consumption were calculated from FAOSTAT and Defra data. The resulting emissions were allocated to the various inventories in which they are registered, e.g. the UK's GHG inventories for agriculture, LUC, energy use and industry, together with those from overseas that are made up by components from our UK consumption of food and drink. Scientific literature relevant to the wider assessment of these scenarios was analysed (and an ecosystems services method was applied) to enable a qualitative assessment to complement the quantitative analysis. ScenariosWe designed a range of consumption and production scenarios to examine options on both the demand and supply sides. These comprise three consumption and three production scenarios. The consumption scenarios are as follows: Consumption Scenario 1. A 50% reduction in livestock product consumption balanced by increases in plant commodities. Consumption Scenario 2. A shift from red meat (beef and lamb) to white meat (pork and poultry). Red meat consumption is reduced by 75%. Consumption Scenario 3. A 50% reduction in white meat consumption balanced by increases in plant commodities. It must be stressed that the nature of scenarios is such that they contain a variety of assumptions about possible future demands and supplies of agricultural commodities. The scenarios are not forecasts. The focus has been on the technical capacity of land and agricultural production, not on the market changes needed to enable change. It should be noted that the balance of supply from the UK and overseas is assumed to remain as it is now. The 50% reduction in livestock products was not applied uniformly across these commodities. Under the reduction scenario (Consumption scenario 1), consumption of milk and eggs is 60% of current consumption, and meat consumption is 36% of current consumption. Sugar consumption is also reduced to align with healthy eating guidelines. Reduction in consumption of livestock products is balanced by increasing plant consumption on the basis of constant food energy supplied. Fruit and vegetable consumption was increased by 50% and basic carbohydrate (e.g. cereals, potatoes) and oil rich commodities (except palm oil) by 33%. Substitution was estimated on the basis of food energy use at the commodity level using FAOSTAT data. Expert opinion was obtained in relation to the viability of consumption change under Scenario 1. This indicated that diets at the consumer level under this scenario are viable from a nutritional viewpoint. It was also noted that Consumption Scenario 1 aligns with healthy eating guidelines in other countries. The production scenarios are focused on the intensity of use of different types of land. The result is a difference in the quantity and type of land ‘released' from production from change that reduces land needs. The production scenarios are: Production Scenario 1. Uniform land release - ‘pro-rata' changes in land requirements across land types. Production Scenario 2. Maximise release of tillable land - ruminant meat production concentrated on lower quality land. Production Scenario 3. Maximise release of low quality land - ruminant meat production concentrated on high quality land. The combination of consumption scenarios 1 and 2 and three production scenarios gives a total of 6 system scenarios. These are complemented by Consumption Scenario 3 giving a total of 7. •4. ResultsLand needsAll consumption change scenarios reduce the total amount of land estimated as required to support the UK food system. A switch from red to white meat increases the need for overseas arable land, although a larger area of UK land that can be tilled is released. Under a reduction scenario, the amount of extra land required for the direct consumption of plant products is less than the amount of arable land released from livestock feed production. The net effect on total overseas arable land needs is a reduction of about 311,000 ha and a net release of about 265,000 ha arable land in the UK. The need for grassland is greatly reduced. The release of grassland with some arable potential ranges between 1.6 to 3.7 million ha depending on where remaining production is concentrated. The release of grassland with no arable potential ranges from 0.7 to 6.9 million ha. Under a reduction scenario, concentrating remaining production on better quality land would almost entirely eliminate sheep and beef production for the UK from the hills, most uplands and less productive lowland areas. Under Consumption Scenario 2 (a shift from beef and sheepmeat to white meat from pigs and poultry), the diet needs of pigs and poultry result in a net increase in demand for overseas grown crops, although considerably more potentially arable land is released in the UK. More arable cropping is needed both in the UK (an additional 55,000 ha) and to a much greater extent overseas (about an additional 466,000 ha), driven largely by soy. However, the release of arable quality grassland in the UK exceeds the increase in overseas arable landed needed for producing this feed. The result is a net release of between 1.6 and 2.9million ha potentially arable land in the UK plus the release of 1.3 to 6.6 millionha of land suitable only for grassland. Under Consumption Scenario 3 (a 50% reduction in white meat consumption balanced by an increase in plant products) the changes are much less complex with no changes in grassland needs. Increases in demand for arable land for direct human consumption amounted to about 154,000 and 172,000 ha (domestic and overseas respectively), but these are more than compensated for by the release of arable land from feed production (341,000 and 668,000ha domestic and overseas respectively). Focusing a reduced cattle and sheep industry on non- arable land would result in the release of substantially more tillable land (currently grassland). In a 50% livestock production consumption reduction scenario, maximising the use of lower grade land (semi-natural grassland, hill land etc.) releases 3.7 million of tillable grassland (including 1.3million ha of good arable land). The opposite approach of withdrawing production from less capable land releases just 1.7 millionha of potentially arable land, with almost no release of the grassland well suited for to arable production. The land-use trade-off is therefore clear. Under a 50% livestock consumption reduction scenario, 2 million ha of tillable grassland is required to compensate for the withdrawal of cattle and sheep production from 6.9 million ha of non-tillable grassland. A 50% reduction in livestock product consumption opens up the opportunity to release about half of UK land currently used for UK food supplies if remaining production is concentrated on the more capable land. If land is released uniformly, almost two-thirds of this release takes place on grassland not suited to arable production and the remaining third is grassland with some arable potential. There would be with higher levels of land release in Scotland, Wales and Northern Ireland than in England. Depending on where the remaining production takes place, a large proportion of land released may be very unproductive, but it can be assumed that about 5 million ha with potential for other agricultural uses would be available, for example for the production of livestock for export (if they did not reduce their livestock consumption), for producing arable biofuel crops, planted woodland and re-wilding (to natural woodland in many cases). Greenhouse gas emissionsAll consumption scenarios reduce greenhouse gas emissions from primary production. The largest reduction is from a livestock reduction scenario (Consumption Scenario 1): from 81 to 66MtCO2e (19% reduction). The switch from red to white meat reduces emissions by 9% and a 50% reduction in white meat consumption by only 3%. The net effect on emissions depends greatly on the alternative use of the grassland released from food production. The study indicates the range of possible consequences on soil and biomass fluxes. If all tillable grassland released from food production was converted to arable use, 8 to 17MtCO2e per year would be released over 20 years through the effects of land use change. Converting all released land with the potential to support good tree growth to woodland would cause a net carbon uptake equivalent to about 7.5 to 9.5MtCO2e per year in soil and wood per year over 20 years. Land use preference (e.g. focusing remaining production on high quality land) has little effect on emissions. This is an important result indicating that supply chain emissions are unresponsive to changes in industry structure with respect to the land used. The location of emissions reductions (UK or overseas) was identified. Currently, we estimate that 36% of primary production emissions are overseas. All scenarios reduce UK emissions while Consumption Scenario 1 has little effect on overseas emissions and Consumption Scenario 2 reduces overseas emissions by 5%. None of the scenarios involve a net export of emissions and the GHG reduction benefits in the UK are proportionally greater than those overseas because of the tight link between UK livestock consumption and production. OTHER EFFECTS Other emissions All consumption scenarios are expected to reduce other emissions. Consumption Scenario 1 halves ammonia emissions. Reductions in nitrate emissions, eutrophication emissions generally, and acidification are almost as large (ca 45%). Biodiversity and carbon sequestration It is widely asserted that grassland, especially semi- natural grassland, has a higher biodiversity value compared with other types of vegetation, natural climax vegetation for example. It is often claimed that the retention of these grasslands is important for the continued delivery of some ecosystem services, for example, carbon sequestration. In many other European countries, the uplands and hills are usually wooded. For example, 32% and 29% of the land area in Germany and France respectively are wooded compared with 12% in the UK. Thus conversion to climax woodland or other forms of forestry is one obvious alternative use for released grassland. Our study has identified benefits for carbon sequestration in soil when grassland is converted to woodland (there should also be potential benefits in the use of harvested wood). Our analysis of land use statistics reveals the large proportion of UK land currently occupied by cattle and sheep. Without these livestock, this grassland (much of which is semi-natural grassland) would revert to the natural vegetation - deciduous woodland in many cases. Our results show that the use of livestock to retain semi-natural grasslands is not dependent on the current high level of livestock product consumption. A 50% reduction in demand still leaves a market which is large enough to support this activity. However, given how a declining market affects all suppliers, a livestock reduction scenario presents special challenges to the maintenance of semi-natural grasslands. Livestock systems provide a wide range of services that are currently used by society. In a reduction scenario, rural areas lose skills and employment in the livestock sector and there would be ramifications for linked industries such as the meat processing or veterinary sectors. Culturally important features, for example, hedgerows and stone walls, and much of the fauna and flora associated with grassland would be no longer needed. In the UK as a whole, land that is most likely to be taken out of production is associated with difficult production conditions. In England, upland moorland and common land now in a semi-natural state could change to fully natural vegetation cover. In upland areas, where the majority of re-wilding under Consumption Scenario 1 and 2 would be located, evidence suggests that various natural communities including scrub, bracken, bramble, and woodland with their own assemblage of flora and fauna are likely to develop, with potential increases in wild herbivores such as deer, hares, and rabbits. The majority of SSSIs currently under-grazed occur in lowland areas, for example in southern and eastern parts of England, and a lack of livestock results in difficulty in applying the grazing pressure required to maintain the semi-natural faunal and floral diversity. Recreational access to the uplands, which is now facilitated by open grassland landscapes, may be impaired and evidence suggests that visitors view the loss of traditional semi-natural landscapes, with associated meadows, hedges, and stone walls, negatively. Whilst a reduction in the current ecosystem service provision associated with livestock production from cattle and sheep can be expected under Consumption Scenarios 1 and 2, the net change is also dependent on the alternative use to which land is put. In upland SSSIs, overgrazing is often problematic and reducing grazing pressure may allow semi-natural habitats to recover, in particular dwarf shrub heaths, bogs, acid grassland and upland habitats. The release of large areas of land could also be used to diversify upland areas. For example, semi-natural upland woodlands have declined by 30-40% since the 1950s and the UK Habitat Action Plan has therefore included a target to increase the area of upland oak woodland through planting or natural regeneration of current open ground. In the lowlands, approximately 10% of the current arable land could be released for other activities, such as bioenergy crops, woodlands, recreational land, wetland creation, nature reserves, flood protection, carbon sequestration, and urban development. Each of these land uses will have its own specific range and flow of ecosystem services associated with it. While in general, the release of agricultural land with high environmental value from food production is not viewed as positive, Defra has concluded that there are likely to be situations where positive outcomes can occur. Economic considerations The reduction in the amount of land needed to supply the UK goes hand-in-hand with a reduction in the value added by agriculture supplying UK consumed food. A 50% reduction in livestock product consumption (Consumption Scenario 1) reduces the UK farm-gate value of livestock products from £7.6 to 3.5 billion. The farm-level economic impact of a change along these lines will depend crucially on what replacement output is found for the land released and on market effects that are beyond the scope of this study. One economic response scenario is that the land resource released remains in agriculture serving export markets. Another strategy is to use the land for non-food purposes. Using biomass energy cropping as a benchmark and assuming a price of £40/tonne dry matter biomass wood, we estimate that replacing the value of the food output of higher quality land released will be challenging, although it is reported that biomass energy is an economically viable alternative to sheep production on uplands.[1] Potential unexpected or unintended consequences Changes to UK crop production The general conclusion that a reduction in livestock production consumption will have little effect in total arable land requirements masks some important regional effects. This scenario will reduce arable crop production for livestock feed and increase arable production for direct human consumption, including a 50% increase in fruit and vegetables. The increase of 0.6 million ha of UK crops for human consumption includes an increase of about 0.2 million ha in potatoes, field vegetables and fruit. Research indicates that agricultural change driven by healthy eating recommendations will result in expansion of production of these crops particularly in the south and east of England.[2] Many of these crops are irrigated and some are protected using for example poly-tunnels. Whilst the change in land use is small in absolute terms, the local effects on water resources and landscape could be significant. It should be noted however that the increase in fresh fruit and vegetable consumption in these scenarios arise from the full implementation of current UK healthy eating guidelines (‘five-a- day') and are not just a consequence reduced livestock product consumption. Potential unexpected or unintended consequencesUneven distribution of economic effects The effect of a contraction in the value of farm output for UK markets will be unevenly distributed. There will be many losers, but also some winners. Given regional land quality characteristics, almost all Welsh, Scottish and Northern Irish farmers would be affected by output contraction counterbalanced by output growth in the south and east of England. Effects on overseas land use The reduction in livestock product consumption will have little effect overall on net overseas land needs. Release of land in South America and the USA used for animal feed, especially soy, will be counter-balanced by increases in a wide range of crops elsewhere. The consumption changes also reduce the need for overseas grassland. This affects three countries in particular: Ireland (dairy products, beef), New Zealand (butter and lamb), and South America (beef). The effect on Brazil is now small as imports have dwindled in recent years but the change would close off the UK as a growth market for Brazilian beef in the longer term. The effects on Ireland are particularly significant. •5. ConclusionThis study has clearly shown that UK land can support consumption change that reduces greenhouse gas emissions from the food system. The reduction in land needed to supply the UK that comes with a reduction in livestock product consumption brings potential environmental benefits and significant opportunities to deliver other products, including other ecosystem services, from UK agricultural land. The study has shown that some risks currently argued as arising from consumption change are small. In particular the study shows that arable land needs will not increase if the consumption of livestock products is decreased. The risk that emissions will be exported is also shown to be small. The identification of the significant potential benefits of consumption change combined with the low risks of unintended consequences has far-reaching implications for guidance to consumers and the development of agricultural policy. The results are broadly applicable to other European countries which means they are relevant to international policy development, for example the reform of the Common Agricultural Policy. [1] Heaton, R.J., Randerson, P.F., Slater, F.M. 1999. The economics of growing short rotation coppice in the uplands of mid-Wales and an economic comparison with sheep production. Biomass and Bioenergy 17: 59-71. [2] Jones, P.J. and Tranter, R.B. 2007. Modelling the impact of different policy scenarios on farm business management, land use and rural employment Project Document No. 13. Implications of a nutrition driven food policy for land use and the Rural Environment. Work package No
Open Access
Greenhouse gas emissions from UK food and drink consumption by systems LCA: current and possible futures
(2010-09-21T00:00:00Z) Williams, Adrian G.; Chatterton, Julia C.; Murphy-Bokern, Donal; Brander, M.; Audsley, Eric; Notarnicola, B.; Settani, E.; Tassielle, G.; Giungato, P.
This work determined the potential to reduce greenhouse gas (GHG) emissions from the UK food system by 70% from a 2005 baseline. A food consumption-orientated inventory was produced including primary agricultural production, food processing, distribution, preparation and disposal. Land use change (LUC) used a top-down approach. The inventory used many sources of data ranging from LCA studies to national level reporting of energy use by sectors of the economy and household surveys. The inventory was created with systems models to compare scenarios for emission reduction. The inventory for the baseline was 250MtCO2e including 100MtCO2e from LUC. Emissions without LUC from the UK food consumption system are about 20% of the current total consumption emissions. Several measures to reduce emissions were investigated, including dietary change, technical efficiency improvement, reducing waste and using non-fossil energy. Only a combination of measures achieved the 70% target reduction, but required major societal changes.
Open Access
The greenhouse gas impacts of converting food production in England and Wales to organic methods
(Nature Publishing Group, 2019-10-22) Smith, Laurence G.; Kirk, Guy J. D.; Jones, Philip J.; Williams, Adrian G.
Agriculture is a major contributor to global greenhouse gas (GHG) emissions and must feature in efforts to reduce emissions. Organic farming might contribute to this through decreased use of farm inputs and increased soil carbon sequestration, but it might also exacerbate emissions through greater food production elsewhere to make up for lower organic yields. To date there has been no rigorous assessment of this potential at national scales. Here we assess the consequences for net GHG emissions of a 100% shift to organic food production in England and Wales using life-cycle assessment. We predict major shortfalls in production of most agricultural products against a conventional baseline. Direct GHG emissions are reduced with organic farming, but when increased overseas land use to compensate for shortfalls in domestic supply are factored in, net emissions are greater. Enhanced soil carbon sequestration could offset only a small part of the higher overseas emissions.
Open Access
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
(2010-03-01T00:00:00Z) Audsley, Eric; Brander, M.; Chatterton, Julia C.; Murphy-Bokern, Donal; Webster, C.; Williams, Adrian G.
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.
Open Access
Implications for welfare, productivity and sustainability of the variation in reported levels of mortality for laying hen flocks kept in different housing systems: A meta-analysis of ten studies
(PLOS (Public Library of Science), 2016-01-06) Weeks, Clare A.; Lambton, Sarah L.; Williams, Adrian G.
Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels of mortality in laying hens. The predicted increase with age was curvilinear with significant variation between the seven breed categories. Mortality was higher in loose housing systems than in cages and variable within system, confirming previous reports. Cumulative mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in those with trimmed beaks. Most data were available for free-range systems (2,823 flocks), where producer recorded CM at 60–80 weeks of age averaged 10% but with a range from 0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen mortality is to increase the relative contribution of breeding overheads, so increasing environmental burdens per unit of production. Reducing CM to levels currently achieved by the 1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently this would enhance hen welfare and better meet the expectation of egg consumers. More research to understand the genetic x environment interaction and detailed records of the causes of mortality is required so that improved genotypes can be developed for different systems and different breeds can be better managed within systems.
Open Access
Is it possible to increase the sustainability of arable and ruminant agriculture by reducing inputs?
(Elsevier, 2009-02) Glendining, M. J.; Dailey, A. G.; Williams, Adrian G.; van Evert, F. K.; Goulding, K. W. T.; Whitmore, A. P.
Until recently, agricultural production was optimised almost exclusively for profit but now farming is under pressure to meet environmental targets. A method is presented and applied for optimising the sustainability of agricultural production systems in terms of both economics and the environment. Components of the agricultural production chain are analysed using environmental life-cycle assessment (LCA) and a financial value attributed to the resources consumed and burden imposed on the environment by agriculture, as well as to the products. The sum of the outputs is weighed against the inputs and the system considered sustainable if the value of the outputs exceeds those of the inputs. If this ratio is plotted against the sum of inputs for all levels of input, a diminishing returns curve should result and the optimum level of sustainability is located at the maximum of the curve. Data were taken from standard economic almanacs and from published LCA reports on the extent of consumption and environmental burdens resulting from farming in the UK. Land-use is valued using the concept of ecosystem services. Our analysis suggests that agricultural systems are sustainable at rates of production close to current levels practiced in the UK. Extensification of farming, which is thought to favour non-food ecosystem services, requires more land to produce the same amount of food. The loss of ecosystem services hitherto provided by natural land brought into production is greater than that which can be provided by land now under extensive farming. This loss of ecosystem service is large in comparison to the benefit of a reduction in emission of nutrients and pesticides. However, food production is essential, so the coupling of subsidies that represent a relatively large component of the economic output in EU farming, with measures to reduce pollution are well-aimed. Measures to ensure that as little extra land is brought into production as possible or that marginal land is allowed to revert to nature would seem to be equally well-aimed, even if this required more intensive use of productive areas. We conclude that current arable farming in the EU is sustainable with either realistic prices for products or some degree of subsidy and that productivity per unit area of land and greenhouse gas emission (subsuming primary energy consumption) are the most important pressures on the sustainability of farming.
Open Access
Livestock and climate change: impact of livestock on climate and mitigation strategies
(Oxford University Press, 2018-11-12) Grossi, Giampiero; Goglio, Pietro; Vitali, Andrea; Williams, Adrian G.
Introduction: According to the United Nations (UN, 2017), the world population increased by approximately 1 billion inhabitants during the last 12 years, reaching nearly 7.6 billion in 2017. Although this growth is slower than 10 years ago (1.24% vs. 1.10% per year), with an average increase of 83 million people annually, global population will reach about 8.6 billion in 2030 and 9.8 billion in 2050. Population growth, urbanization, and income rise in developing countries are the main driver of the increased demand for livestock products (UN, 2017). The livestock sector requires a significant amount of natural resources and is responsible for about 14.5% of total anthropogenic greenhouse gas emissions (7.1 Gigatonnes of carbon dioxide equivalents for the year 2005; Gerber et al., 2013). Mitigation strategies aimed at reducing emissions of this sector are needed to limit the environmental burden from food production while ensuring a sufficient supply of food for a growing world population. The objectives of this manuscript are to 1) discuss the main greenhouse gas emissions sources from the livestock sector and 2) summarize the best mitigation strategies.
Open Access
Modelling the production impacts of a widespread conversion to organic agriculture in England and Wales
(Elsevier, 2018-05-24) Smith, Laurence G.; Jones, Philip J.; Kirk, Guy J. D.; Pearce, Bruce D.; Williams, Adrian G.
We assess the production impacts of a 100% conversion to organic agriculture in England and Wales using a large-scale linear programming model. The model includes a range of typical farm structures, scaled up across the available land area, with the objective of maximising food production. The effects of soil and rainfall, nitrogen (N) supply/offtake and livestock feed demand are accounted for. Results reveal major reductions in wheat and barley production, whilst the production of minor cereals such as oats and rye increase. Monogastric livestock and milk production also decreased considerably, whilst beef and sheep numbers increased. Vegetable production was generally comparable to that under conventional farming. Minimising the area of fertility building leys and/or improving rates of N fixation increased the food supply from organic agriculture at the national level. The total food output, in terms of metabolisable energy, was 64% of that under conventional farming. This would necessitate substantial increases in food imports, with corresponding expansion of cultivated agricultural land overseas. Significant changes in diet and reductions in food waste would be required to offset the production impacts of a 100% conversion to organic farming.
Open Access
UK food and nutrition security during and after the COVID-19 pandemic
(Wiley, 2021-02-19) Rivington, Mike; King, R.; Duckett, D.; Iannetta, P.; Benton, T. G.; Burgess, Paul J.; Hawes, C.; Wellesley, L.; Polhill, J. G.; Aitkenhead, M.; Lozada‐Ellison, L.‐M.; Begg, G.; Williams, Adrian G.; Newton, A.; Lorenzo‐Arribas, A.; Neilson, R.; Watts, C.; Harris, Jim A.; Loades, K.; Stewart, D.; Wardell‐Johnson, D.; Gandossi, G.; Udugbezi, E.; Hannam, Jacqueline A.; Keay, Caroline
The COVID‐19 pandemic is a major shock to society in terms of health and economy that is affecting both UK and global food and nutrition security. It is adding to the ‘perfect storm’ of threats to society from climate change, biodiversity loss and ecosystem degradation, at a time of considerable change, rising nationalism and breakdown in international collaboration. In the UK, the situation is further complicated due to Brexit. The UK COVID‐19 Food and Nutrition Security project, lasting one year, is funded by the Economic and Social Research Council and is assessing the ongoing impact of COVID‐19 on the four pillars of food and nutrition security: access, availability, utilisation and stability. It examines the food system, how it is responding, and potential knock on effects on the UK’s food and nutrition security, both in terms of the cascading risks from the pandemic and other threats. The study provides an opportunity to place the initial lessons being learnt from the on‐going responses to the pandemic in respect of food and nutrition security in the context of other long‐term challenges such as climate change and biodiversity loss.
Open Access
The water footprint of English beef and lamb production
(2011-05-25) Chatterton, Julia C.; Hess, Tim M.; Williams, Adrian G.
Recent reports highlighting large quantities of water required to produce a kilo of meat have attracted media attention, leading to debates over the role of meat in a sustainable diet. Such reports frequently quote figures based on global averages and therefore conceal significant regional variation, ignoring the source of the water required and local climatic conditions. This report attempts to quantify the water footprint of English beef and lamb production, combining the water simulation model Wasim and the Cranfield Life Cycle Assessment model to calculate the water required to produce a tonne of beef and lamb meat. This method accounts for all water required by grass and crops in addition to drinking water and other requirements. Water use is considered in three categories; green, blue and grey water. Results show that beef has a water footprint of 17,700 m3/t carcase weight and lamb 57,800 m3/t. Of these, 84% and 97% respectively is green water use, i.e. evapotranspiration of rainfall on crop and grassland. Without this breakdown there is no distinction between rainfall and irrigation supply (blue water), which means that UK beef production may appear similar in impact to countries where irrigation of feed crops is dominant. This report highlights the importance of considering water use in context; in this case, for a temperate, wet climate such as England where crop and grassland water requirements are adequately met by green water from rainfall. Upland and hill production systems have higher water footprints, mostly because grass yield is lower. However, it is shown that rainfall surplus per tonne grass production is still highest in these regions, so that export of water for other human purposes is possible from these regions.