Marginal Abatement Cost Curves for UK Agricultural Greenhouse Gas Emissions

This article addresses the challenge of developing a ‘bottom‐up’ marginal abatement cost curve (MACC) for greenhouse gas (GHG) emissions from UK agriculture. An MACC illustrates the costs of specific crop, soil and livestock abatement measures against a ‘business as usual’ scenario. The results indicate that in 2022 under a specific policy scenario, around 5.38 Mt CO₂ equivalent (e) could be abated at negative or zero cost. A further 17% of agricultural GHG emissions (7.85 Mt CO₂e) could be abated at a lower unit cost than the UK Government’s 2022 shadow price of carbon [£34 (tCO₂e)^?1]. The article discusses a range of methodological hurdles that complicate cost‐effectiveness appraisal of abatement in agriculture relative to other sectors.     

Methodology to calculate the carbon footprint of household land use in the urban planning stage

The growing concerns of climate change require implementing measures to quantify, to monitor and to minimize greenhouse gas (GHG) emissions. Nonetheless, most of the measures available are not easy to define or execute because they rely on current emissions and have a corrective character. To address this issue, a methodology to characterize GHG emissions that allows implementing preventive measures is proposed in this paper. The methodology is related to household urban planning procedures and considers urban infrastructures to characterize GHG emissions and to execute preventive measures based on sustainability design criteria. The methodology has been tested by applying it to a set of medium-sized municipalities with average GHG emissions from 6,822.32 kgCO_2eq/year to 5,913.79 kgCO_2eq/year for every residential unit. The results indicate that the greatest pollutant source is transport, especially in the issuance of street network design, followed by gas and electricity consumption. The average undevelopable land area required for the complete GHG emissions capture amounts to 3.42 m² of undevelopable land for every m² of urbanizable land and 9.02 m² of undevelopable land for every m² of built land.     

Smallholder farms’ adaptation to the impacts of climate change: Evidence from China’s Loess Plateau

The impacts of climate change on agriculture in developing countries will depend on the extent to which agricultural production in those regions adapts to climate change’s influences. This study uses a whole-farm land use optimisation approach to explore climate change impacts, when including adaptation, on farm profitability, production and associated greenhouse gas (GHG) emissions in the Loess Plateau of northern China. The results show that with adaptation activities, the losses in smallholder farm profitability caused by the climate change could be moderate. Declining rainfall results in land use changes that generate higher on-farm GHG emissions with the most economically beneficial adaptations. With 5 % or 10 % decline in annual rainfall, the introduction of agricultural carbon tax would generate substantial reduction in on-farm GHG emissions. With 30 % rainfall reduction, agricultural carbon tax is not likely to bring about considerable emission reduction. The economically optimised land uses are generally sensitive to potential changes. When rainfall reductions appear, there is a clear trend toward reducing cropping area and transiting to pasture. With 5–10% rainfall reductions, increasing agricultural carbon tax with same rainfall reduction leads to the expansion in cropping enterprises. However, with 30 % rainfall reduction, land allocations are not sensitive to agricultural carbon tax. When with declining annual rainfall, in the optimal enterprises more oats-pasture rotations are employed to reduce wheat dominated rotations. Besides land use patterns, adaptations through altering farm management practices are also necessary. The economically optimised sheep flock would be increased considerably with declining rainfall. Overall, policymakers are suggested to initial more educational schemes to tell smallholder farmers how to make the best use of available adaptation strategies and consider changes in climate when design and implement agricultural policy.     

Marginal abatement costs of greenhouse gas emissions: broadacre farming in the Great Southern Region of Western Australia

Broadacre agriculture is a major emitter of greenhouse gases (GHG). To improve efficiency of climate change policies, we need to know the marginal abatement costs of agricultural GHG. This article combines calculations of on‐farm GHG emissions with an input‐based distance function approach to estimate the marginal abatement costs for a broadacre farming system in the Great Southern Region of Western Australia. The results show that, in the study region, the average marginal abatement cost for the 1998–2005 periods was $29.3 per tonne CO₂‐e. Farms with higher crop output shares were found to have higher marginal abatement costs. Overall, our results indicate that broadacre agriculture is among the lowest cost sources of GHG mitigation.     

Quantifying the impact of farmers' social networks on the effectiveness of climate change mitigation policies in agriculture

To reduce agricultural greenhouse gas (GHG) emissions, farmers need to change current farming practices. However, farmers' climate change mitigation behaviour and particularly the role of social and individual characteristics remains poorly understood. Using an agent-based modelling approach, we investigate how knowledge exchange within farmers' social networks affects the adoption of mitigation measures and the effectiveness of a payment per ton of GHG emissions abated. Our simulations are based on census, survey and interview data for 49 Swiss dairy and cattle farms to simulate the effect of social networks on overall GHG reduction and marginal abatement costs. We find that considering social networks increases overall reduction of GHG emissions by 45% at a given payment of 120 Swiss Francs (CHF) per ton of reduced GHG emissions. The per ton payment would have to increase by 380 CHF (i.e., 500 CHF/tCO₂eq) to reach the same overall GHG reduction level without any social network effects. Moreover, marginal abatement costs for emissions are lower when farmers exchange relevant knowledge through social networks. The effectiveness of policy incentives aiming at agricultural climate change mitigation can hence be improved by simultaneously supporting knowledge exchange and opportunities of social learning in farming communities.     

Assessment of land use and land cover changes and valuation of carbon stocks in the Sergipe semiarid region,Brazil: 1992–2030

The semiarid region in the state of Sergipe, Brazil, approximately 11,000 km², has experienced high deforestation rates in the last decades, which ultimately contribute to global climatic changes. The valuation of ecosystem services of CO₂ sequestration can support definition of environmental policies to decrease deforestation in that region. This study aimed to assess land use and land cover changes in the Sergipe semiarid region between 1992 and 2017 by applying remotely sensed data and technics; simulate the land use and land cover changes between 2017 and 2030 by applying a cellular automaton model, by assuming current land use trends (Business as Usual – BAU) as a reference scenario, and a more conservative scenario (Protected Forest – PF), in which was assumed an effective enforcement of the Brazilian Forest Code established in 2012; simulate the carbon stocks by 2017 assuming the BAU and PF scenarios by 2030, and estimate the Carbon balance between the 2030 and 2017 scenarios; and estimate the economic valuation of carbon emission and sequestration by using the InVEST software. The results showed that agriculture (cropped lands) was main driver of the landscape changes in the study area, which increased 14% by 2017, a net increase of 1494.45 km². The results showed that the total Carbon emissions would reach 736,900 Mg CO₂-eq by assuming the BAU scenario, which would increase the cost of opportunity up to US$ 17.7 million and a social carbon cost varying between US$ 10.3 and US$ 30.2 million. The restoration of the permanent preservation areas could contribute to increase Carbon sequestration up to 481,900 Mg CO₂-eq by 2030, which is equivalent cost of US$ 11.6 million. The natural landscape in the Sergipe semiarid region was strongly affected by deforestation activities occurred between 1992 and 2017. It requires, therefore, effective actions to support and promote restoration of degraded areas. The forested areas within the Sergipe semiarid region were the most affected type of vegetation because of expansion of agricultural fields soil exposures (Exposed Land). Environmental assessments based on scenarios and economic valuations can provide crucial information to support policy and decision makers to improve strategies for environmental management and conservation.     

Making explicit agricultural ecosystem service trade-offs: a case study of an English lowland arable farm

European farmland hosts a species assemblage of animals and plants which have undergone declines through the late twentieth and early twenty-first centuries, at least partly as a result of increased productivity. Further increases in human populations, changes in availability and cost of raw materials, policy constraints, price volatility and climatic changes will further drive greater efficiency and high yields in agriculture, with the risk of further adverse environmental impacts. We assess the effects of different management priorities (production-driven cropping vs. wildlife-friendly farming) at an arable farm in eastern England on food production, greenhouse gas (GHG) emissions and biodiversity. We modelled one actual and three alternative cropping scenarios using actual yields from the farm over 13 years, to calculate total yields and those foregone for agri-environmental measures. We measured crop yields, relative abundance of 19 farmland bird species, and CO₂ and N₂O emissions related to crop production. Removing up to 10.5% of land from production coupled with a more diverse rotation (including legumes) resulted in a large increase in breeding birds (177%) and reduction of 9.4% in GHG emissions at the cost of 9.6% of food energy. Food protein lost was only 2.9%. A smaller increase in bird numbers of 50% could be achieved at a much smaller cost to yield (～1.7% energy or protein) but with correspondingly smaller emissions reductions (1.2%). Results are discussed within the context of continued biodiversity loss to agriculture, increasing food demand and changing diets.     

Climate change impacts on rain-fed and irrigated rice yield in Malawi

There is extensive scientific evidence on climate impacts and adaptation in rice (Oryza sativa L.), but the majority relates to production in South Asia and China. Only a handful of studies have been conducted in Sub-Saharan Africa and none in Malawi. In this paper, the climate impacts on rain-fed and irrigated rice yield have been assessed by combining the downscaled outputs from an ensemble of general circulation models (GCM) (HADCM3, INCM3 and IPCM4) with data from the LARS-WG weather generator to drive the CERES-Rice crop model. This was calibrated and validated using 10 years (2001–2010) field data from three rice schemes to simulate the baseline (1961–1990) yield (t?ha^?1) and then model future yield changes for selected (B1 and A2) emissions’ scenarios for the 2050s. Although relatively small increases in average yield were projected (+8% and +5% for rain-fed and irrigated rice, respectively), there was large uncertainty (?10% to +20% yield change) when considering different GCMs and emission scenario. Farmer responses to cope with the projected impacts include both autonomous and planned adaptation strategies, such as modifying planting dates to maximize crop growth calendars and available soil moisture, increased use of on-farm water conservation measures and land levelling to improve water efficiency in rice schemes dependent on surface irrigation.     

Potential of woody biomass production for motivating widespread natural resource management under climate change

In this study we assessed the potential of woody biomass (short-rotation Mallee Eucalypts) for renewable energy generation as an economically viable way of motivating widespread natural resource management under climate change in the 11.9 million ha Lower Murray agricultural region in southern Australia. The spatial distribution of productivity of agricultural crops and pasture, and biomass was modelled. Average annual economic returns were calculated under historical mean (baseline) climate and three climate change scenarios. Economically viable areas of biomass production were identified where the profitability of biomass is greater than the profitability of agriculture under each scenario for three factory gate biomass prices. The benefits of biomass production for dryland salinisation, wind erosion, and carbon emissions reduction through biomass-based renewable energy production were also modelled. Depending on climate scenario, at the median price assessed ($40/tonne) biomass production can generate $51.4–$88 M in annual net economic returns, address 41,226–165,577 ha at high risk of dryland salinisation and 228,000–1.4 million ha at high risk of wind erosion, and mitigate 10.4–12 million tonnes of carbon (CO₂^−e) emissions annually. Economically viable areas for biomass production expanded under climatic warming and drying especially in more marginal agricultural land. Under the baseline, the area at high risk of dryland salinisation was more than double that at high risk of wind erosion. However, under climatic warming and drying the relative importance of these two natural resource management objectives switched with the area at high risk of wind erosion becoming much larger. As biomass production can achieve multiple natural resource management objectives, it may provide a land use policy option that is adaptable to changing priorities and economically resilient given climatic uncertainties. For such a significant and enduring land use change policy it is prudent to assess both the economic and environmental potential under climate change.     

滨海滩涂垦区主要大田作物生产碳足迹研究*——以江苏省盐城市为例

[目的]由于自然要素组合的特殊性,与传统内陆农区相比,滩涂围垦区农业生产特点鲜明。摸清该区大田作物碳足迹,可减少区域碳排放,提升农业生产效率,优化区域资源配置。[方法]采用生命周期评价理论结合IPCC田间温室气体计算方法,建立大田作物碳足迹评估模型,估算滨海滩涂垦区大田作物温室气体排量。[结果](1)滨海滩涂地区大田作物的碳足迹(以CO_2当量)总体在0.63～0.769kg/kg范围内,不同作物的碳足迹由大到小依次为:玉米0.769±0.224kg/kg、水稻0.739±0.241kg/kg、小麦0.636±0.183kg/kg和大麦0.630±0.184kg/kg;(2)氮肥生产和施用环节对该区碳足迹贡献度最大,贡献率分别为26.46%～37.12%和29.06%～51.94%。该地碳足迹数值和结构上呈显著地域化特点,与中国其他地区相比,氮肥施用贡献度大,水田灌溉贡献度大。[结论]降低该地区碳足迹,重点关注施氮和水稻灌溉工程两个方面。采用降低施氮量、提高氮肥利用率、发展节水农业与生态农业等措施,可达到降低碳足迹的目的。     

The effects of repeated soil wetting and drying on lowland rice yield with system of Rice Intensification (SRI) methods

In lowland rice farming, water management is the most important practice that determines the productivity of other inputs, e.g. nutrients, herbicides, pesticides, farm machinery, microbial activity, mineralization rates. Deliberate flooding or poor drainage that keeps soil saturated is detrimental to crops and degrades soil quality. This study evaluated whether rice grain yield could be increased relative to continuous flooding by using the management practices of the System of Rice Intensification (SRI). The effects of SRI's repeated wetting and drying cycles plus different plant populations were investigated at Sapu Research Station in The Gambia, on an alluvial soil between 2000 and 2002. The water management practices proposed for SRI were found to be beneficial to rice growth. At 20 cm spacing, average grain yield with SRI practice was 7.3 t ha^?1 compared with 2.5 t ha^?1 under continuous flooding. At 30 cm spacing SRI practice yielded 6.6 t ha^?1, while under continuous flooding, grain yield was only 1.7 t ha^?1. Even wider spacing did not produce higher yield. At 40 cm spacing, SRI management gave 4.7 t ha^?1, while continuous flooding yielded 1.3 t ha^?1. Thus overall, SRI practices gave better results than continuous flooding. This was probably as a result of increased nutrient availability and superior growing conditions which enhanced physiological development and grain yield. Rewetting dry soil reportedly facilitates nitrogen mineralization. The phenomenon of having a flush of nitrogen mineralization occurring after rewetting dry soil was first reported by Birch in 1958. This intensive pathway of nitrogen mineralization and nitrogen availability has potential to increase lowland rice yields in ways consistent with sustainable agricultural production.     

Carbon footprint of pigmeat in Flanders

Although several international carbon footprint (CF) calculation initiatives have been developed, studies that focus specifically on estimating the CF of pigmeat are rather limited. This paper describes the application of a CF methodology, based on lifecycle assessment of greenhouse gas (GHG) emissions, for Flemish pigmeat production using the Publicly Available Specification methodology (PAS2050, BSI 2011), which is at present the most developed method and relevant within the agricultural and horticultural sector. Both primary and secondary data have been used to model the meat system through a chain approach. The results are reported using the functional unit of 1 kg of deboned pigmeat; and range from 4.8 to 6.4 kg CO₂ eq./kg of deboned pig meat. A sensitivity analysis has been executed on changes in herd and feed characteristics. The results have been compared with other studies on the CF of pigmeat in the European Union and with CF studies on milk and beef production in Flanders. Furthermore, two major hotspots in the CF have been defined: the composition and production of feed, and manure production and usage. It is important to mention that the CF is a good indicator for GHG emissions, but it is not an indicator for environmental impact in general. This paper helps to fill the void in the CF literature which existed around pigmeat products and to define a benchmark for CF of pigmeat.     

Setting Climate Action as the Priority for the Common Agricultural Policy: A Simulation Experiment

We quantitatively assess the impacts of re-allocating budgetary resources within Pillar 1 of the EU's Common Agricultural Policy (CAP) from direct income support to a direct greenhouse gas (GHG) reduction subsidy for EU farmers. The analysis is motivated by the discussion on the future CAP, with calls for both an increased ambition on climate action from the agricultural sector and for a more incentive-based delivery system of direct payments under strict budgetary restrictions. By conducting a simulation experiment with an agricultural partial equilibrium model (CAPRI), we are able to factor in farmers’ supply and technology-adjusting responses to the policy change and to estimate the potential uptake of the GHG-reduction subsidy in EU regions. We find that a budget-neutral re-allocation of financial resources towards subsidised emission savings can reduce EU agricultural non-CO₂ emissions by 21% by 2030, compared to a business-as-usual baseline. Two-thirds of the emission savings are due to changes in production levels and composition, implying that a significant part of the achieved GHG reduction is offset globally by emission leakage. At the aggregated level, the emission-saving subsidy and increased producer prices compensate farmers for the foregone direct income support, but differences in regional impacts indicate accelerated structural change and heterogeneous income effects in the farm population. We conclude that the assumed regional budget-neutrality condition introduces inefficiencies in the incentive system, and the full potential of the EU farming sector for GHG emissions reduction is not reached, leaving ample room for the design of more efficient agricultural policies for climate action.     

Cooperative membership and adoption of green pest control practices: Insights from rice farmers

Reducing the use of chemical pesticide while preserving crop yield is a practical strategy that makes agricultural production economically, socially and environmentally sustainable. Although the adoption of green pest control practices can help achieve such a goal, its adoption rate remains quite low. This study explores whether membership in agricultural cooperatives improves smallholder farmers' adoption of green pest control practices, utilising farm-level data surveyed from rice farmers in China. To enrich our understanding, we also investigate how the adoption of green pest control practices mediates the effects of cooperative membership on chemical pesticide expenditures. An endogenous switching probit model and a bootstrap-based mediation method are employed to achieve these goals. The empirical results show that cooperative membership significantly increases the probability of adopting physical pest control practices (e.g. pest-killing lamps or sticky plate traps) and biological pest control practices (e.g. biopesticides) by 6% and 19%, respectively. Cooperative membership significantly reduces chemical pesticide expenditures through its mediation effect on improving the probability of adopting biological pest control practices. There is also a complementary relationship between physical and biological pest control practices in pest management of rice production. The adoption of physical pest control practices significantly increases rice yield, while the adoption of biological pest control practices does not.     

Energy productivity and greenhouse gas emission intensity in Dutch dairy farms: A Hicks–Moorsteen by-production approach under non-convexity and convexity with equivalence results

The agricultural sector is currently confronted with the challenge to reduce greenhouse gas (GHG) emissions, whilst maintaining or increasing production. Energy-saving technologies are often proposed as a partial solution, but the evidence on their ability to reduce GHG emissions remains mixed. Production economics provides methodological tools to analyse the nexus of agricultural production, energy use and GHG emissions. Convexity is predominantly maintained in agricultural production economics, despite various theoretical and empirical reasons to question it. Employing non-convex and convex frontier frameworks, this contribution evaluates energy productivity change (the ratio of aggregate output change to energy use change) and GHG emission intensity change (the ratio of GHG emission change to polluting input change) using Hicks-Moorsteen productivity formulations. We consider GHG emissions as by-products of the production process by using a multi-equation model. Given our empirical specification, non-convex and convex Hicks-Moorsteen indices can coincide under certain circumstances, which leads to a series of theoretical equivalence results. The empirical application focuses on 1,510 observations of Dutch dairy farms for the period of 2010–2019. The results show a positive association between energy productivity change and GHG emission intensity change, which calls into question the potential of on-farm, energy-efficiency-increasing measures to reduce GHG emission intensity.     

Cost and environmental efficiency of rice farms in South Korea

We examine cost and nutrient use efficiency of farms and determine the cost to move farms to nutrient‐efficient operation using Data Envelopment Analysis (DEA) with a dataset of 96 rice farms in Gangwon province of South Korea from 2003 to 2007. Our findings show that improvements in technical efficiency would result in both lower production costs and better environmental performance. It is, however, not costless for farms to move from their current operation to the environmentally efficient operation. On average, this movement would increase production costs by 119% but benefit the water system through an approximately 69% reduction in eutrofying power (EP). The average estimated cost of each EP kg of aggregate nutrient reduction is approximately one thousand two hundred won. For technically efficient farms, there is a trade‐off between cost and environmental efficiency. We also find that the environmental performance of farms varies across farms and regions. We suggest that agri‐environmental policies should be (re)designed to improve both cost and environmental performance of rice farms.     

Bioelectricity in Malaysia: economic feasibility,environmental and deforestation implications

We investigate the economic feasibility of bioelectricity production from biomass in Malaysia and its impact on greenhouse gas (GHG) emissions and storage, agricultural prices, agricultural employment and deforestation. For this purpose, we develop a partial equilibrium model that projects agricultural prices, production, imports, exports, domestic consumption and land use in 5‐year increments between 2015 and 2065. Our results show that by 2030 biomass‐generated electricity can supply 36.5 per cent of the electricity generated in Malaysia, 16 times more than the 2016 electricity supply from biomass. Increased bioelectricity production from biomass will significantly reduce GHG emissions and will help Malaysia meet its commitment in the Paris Agreement to mitigate GHG emission by 45 per cent before 2030. Our modelling shows that biomass‐generated electricity creates a derived demand for waste biomass that expands the area of oil palm plantations. The expansion lowers agricultural prices, boosts agricultural employment and leads to some deforestation as landowners clear rainforest to plant oil palm trees. Nonetheless, the deforestation does not increase GHG emissions since GHG gains from bioelectricity significantly exceed GHG losses from deforestation.     

Mitigation potential and costs for global agricultural greenhouse gas emissions1

Agricultural activities are a substantial contributor to global greenhouse gas (GHG) emissions, accounting for about 58% of the world's anthropogenic non‐carbon dioxide GHG emissions and 14% of all anthropogenic GHG emissions, and agriculture is often viewed as a potential source of relatively low‐cost emissions reductions. We estimate the costs of GHG mitigation for 36 world agricultural regions for the 2000–2020 period, taking into account net GHG reductions, yield effects, livestock productivity effects, commodity prices, labor requirements, and capital costs where appropriate. For croplands and rice cultivation, we use biophysical, process‐based models (DAYCENT and DNDC) to capture the net GHG and yield effects of baseline and mitigation scenarios for different world regions. For the livestock sector, we use information from the literature on key mitigation options and apply the mitigation options to emission baselines compiled by EPA.     

Evolution and future direction of intensified agriculture in the central mid-hills of Nepal

Nepalese mid-hill farmers have shifted from a subsistence-based farming system to an intensified farming system. This paper attempts to describe the evolution of the process of agricultural intensification in the mid-hill region by examining external drivers, trends in fertilizer use, landholding, cropping patterns, irrigation and labour use in the years 1989, 1999 and 2009. Data were obtained by means of structured interviews, focus group discussions, key informant interviews and field observations. The study revealed that modern technology and the involvement of NGOs have facilitated the agricultural intensification process in three ways: (i) by providing access to technology without any financial cost to the farmer, (ii) by increasing the variety and number of crops and encouraging farmers to discontinue crops that had pest problems and (iii) by maximizing the use of chemical fertilizers to increase production. Results showed a significant increase in the application of urea and diammonium phosphate (DAP) and a decrease in the application of farm yard manure (FYM) and muriate of potash from 1989 to 2009 (p < 0.001). The average landholding of 0.76ha in 1989 was reduced to 0.63ha by 2009. The number of crops (rice, maize or millet) cultivated per year increased to at least three crops with the introduction of potatoes and spring rice; however, some crops such as sugarcane and tobacco were not continued as a result of pest problems. Increased nitrogen input could lead to increased N₂O emissions; therefore, a better understanding of nitrogen fertilization and quantification of N₂O emissions from intensified agriculture is urgently needed to assess the possible environmental impact of input intensification.     

Improving China’s food and environmental security with conservation agriculture†

China has achieved impressive increases in agricultural output in recent decades. Yet, past approaches centred on a growing use of fertilizers, pesticides, fuel and water are not likely to achieve the required 30–50% additional increases in food production by mid-century. We show that efficiencies of production are falling and the costs of environmental harm are increasing. Agricultural innovations that improve natural capital are urgently needed. Conservation agriculture (CA) is now practised on >8?Mha in China and is offering promising prospects of both enhanced yields and environmental services. Our meta-analysis of 60 papers with 395 observations in China shows notable benefits from CA. Mean yield increase was 4.5% or 263?kg?ha^?1 for wheat, 8.3% or 424?kg?ha^?1 for maize, and 1.65% or 250?kg?ha^?1 for rice. In 34 datasets from 22 published papers (experimental duration: 2–17 years), 26 datasets (76.5%) show that CA increased yield and soil organic carbon (mean SOC increase of >3?g.kg^?1 in 0–10?cm soil depth) when compared with traditional tillage. Key priorities for the spread of more sustainable forms of agriculture in China are national policy and financial support, better coordination across agencies, and better extension for farmers.