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Actual yield versus potential yield of dynamic crops within each potential yield class. Crosses are minimums and maximums, whiskers go from the 20th to the 80th percentile. X-axis in GJ/ha/year ranges from 0 to 251. See Figure 6 for a map of the difference between potential and actual yields of dynamic crops.
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Interactions between food demand, biomass energy and forest preservation are driving both food prices and land-use changes, regionally and globally. This study presents a new model called Nexus Land-Use version 1.0 which describes these interactions through a generic representation of agricultural intensification mechanisms. The Nexus Land-Use mode...
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Context 1
... ρ min j is the y-intercept, defined as the no-inputs yield. Its value 20 is set to ten percent of the potential yield ρ max j . This choice is somewhat arbitrary but consistent with observations. Indeed, actual yields on the African continent, thought to be close to the minimum yield, are approximately equal to 10 % of the potential yield (see Fig. 9). However it may lead to an underestimation in temperate regions (T. DoréDor´Doré, personal communication, 2011 From an economic point of view, Eq. (12) is a production function representing the technical relationship between a quantity of output (yield) and a combination of inputs (fertilisers and ...
Context 2
... each grid cell is set to the production function can be considered as a form of yield response function to fertiliser application that can be simulated by crop models ( Brisson et al., 2003;Godard et al., 2008), and generalized to all types of fertilisers (nitrogen, phosphorus, potassium) and to pesticides. The yield per unit of land is given by: Fig. 9. Actual yield versus potential yield of dynamic crops within each potential yield class. Crosses are minimums and maximums, whiskers go from the 20th to the 80th percentile. X-axis in GJ/ha/year ranges from 0 to 251. See Fig. 6 for a map of the difference between potential and actual yields of dynamic crops. arate pasturelands and ...
Citations
... an agricultural supply-side model of the European Union, AROPAj (Jayet et al., 2018) and a global scale partial equilibrium model, NLU (Souty et al., 2012). These models allow us to analyze and compare the effects of the policy in terms of agricultural production, prices, land use change and greenhouse gas emissions at local and global scales. ...
... NLU, the agricultural sector is divided into 12 global regions, inter-connected by international trade. A detailed description can be found in Souty et al. (2012) or in Brunelle et al. (2015). ...
This paper explores the effects of a public policy that reduces by 50% the use of mineral nitrogen in European agriculture. Our results show that, for the European Union, halving mineral fertilizer use leads to: a decrease in agricultural production, a substantial increase in nitrogen use efficiency, lower use of organic fertilizer and a loss of agricultural competitiveness. At the global level, it leads to greater nitrogen consumption if no measure is taken on the demand side. Ultimately, our research highlights the critical importance of supply side adjustments, particularly in terms of cropland area expansion.
... The term β 0 is the maximum yield for the first unit of land entering production. Use of Eq. (1) shows that lower yielding lands enter production in the face of higher crop prices only after the higher yielding lands are used when prices are too low to support farming on lower yielding lands (Bromley, 2009;Kratena, 2008;Souty et al., 2012). The complete optimization model contains 24 blocks of equations, 2038 individual equations, 24 blocks of variables, and 2759 individual variables, from which 1932 have nonlinear elements, making it too large to include in the body of this text. ...
... Today, these theories are still directly applied in some land use assessments [18,19]. Many global land use models are rooted in classical rent theories by allocating land according to a profit function that depends on the intrinsic qualities of land provided by vegetation models (usually in terms of climatic potential yields) [20][21][22] or based on index of agricultural suitability [23]. Land supply elasticities are also generally used to determine land conversion rates in a given location. ...
Classical land rent theories imply that the best land is cultivated first. This principle forms the basis of many land-use studies, but empirical evidence remains limited, especially on a global scale. In this paper, we estimate the effects of agricultural suitability and market accessibility on the spatial allocation of cultivated areas at a 30 arc-min resolution in 15 world regions. Our results show that both determinants often have a significant positive effect on the cropland fraction, but with large variations in strength across regions. Based on a quantile analysis, we find that agricultural suitability is the dominant driver of cropland allocation in North America, Middle East and North Africa and Eastern Europe, whereas market accessibility shows a stronger effect in other regions, such as Western Africa. In some regions, such as South and Central America, both determinants have a limited effect on cropland fraction. Comparison of high versus low quantile regression coefficients shows that, in most regions, densely cropped areas are more sensitive to agricultural suitability and market accessibility than sparsely cropped areas.
... The goal of EMF33 is to understand and improve the modeling of bioenergy supply and demand in the IAMs (Rose et al. 2014, this issue). We selected six state-of-the-art models that allow us to compute agriculture and land-use market and food-security interactions, considering high bioenergy demand: AIM (Fujimori et al. 2012Hasegawa et al. 2017), FARM (Sands et al. 2017), GCAM , GLOBIOM (Frank et al. 2017;Fricko et al. 2017;Havlík et al. 2014), MAgPIE (Bodirsky et al. 2014Popp et al. 2014a), andNLU (Brunelle et al. 2015;Souty et al. 2012);Brunelle et al. 2015). AIM, FARM, GCAM, GLOBIOM, and MAgPIE feature land-use competition among food production, bioenergy crop production, and afforestation, whereas NLU employs a food-first policy whereby bioenergy does not compete with food production. ...
Bioenergy is expected to play an important role in the achievement of stringent climate-change mitigation targets requiring the application of negative emissions technology. Using a multi-model framework, we assess the effects of high bioenergy demand on global food production, food security, and competition for agricultural land. Various scenarios simulate global bioenergy demands of 100, 200, 300, and 400 exajoules (EJ) by 2100, with and without a carbon price. Six global energy-economy-agriculture models contribute to this study, with different methodologies and technologies used for bioenergy supply and greenhouse-gas mitigation options for agriculture. We find that the large-scale use of bioenergy, if not implemented properly, would raise food prices and increase the number of people at risk of hunger in many areas of the world. For example, an increase in global bioenergy demand from 200 to 300 EJ causes a − 11% to + 40% change in food crop prices and decreases food consumption from − 45 to − 2 kcal person−1 day−1, leading to an additional 0 to 25 million people at risk of hunger compared with the case of no bioenergy demand (90th percentile range across models). This risk does not rule out the intensive use of bioenergy but shows the importance of its careful implementation, potentially including regulations that protect cropland for food production or for the use of bioenergy feedstock on land that is not competitive with food production.
... LPJml is a spatially explicit model that simulated carbon and water cycles by solving the energy balance (Gerten et al., 2013(Gerten et al., , 2004Sitch et al., 2003). A couple of IAM are using LPJml as partial biophysical inputs into their system (Souty et al., 2012;van den Berg et al., 2016). LPJml is used to calculate maximum potential vegetation and crop production. ...
This deliverable describes the initial background and conceptual framework of the Land-use sub-module in the WILIAM (WIthin Limits Integrated Assessment Model) set of Integrated Assessment Models developed in the LOCOMOTION project.
... Land use models integrate several human activities and associated ecological dynamics in the same framework (Millennium Ecosystem Assessment Board 2005, Newbold et al. 2016, Verburg et al. 2002. In this thesis, I used the land use model called NLU (Souty et al. 2012, Brunelle et al. 2015. ...
... The NLU is not only an economic model, it also include environmental characteristics with plant growth models (Souty et al. 2012) and scenarios of climate change impacts on yields (Müller & Robertson 2014). In this thesis, I added nitrogen balances which estimate the natural nitrogen fertilization of crops through biological fixation of legumes and deposition. ...
... Also, the use of linear programming in NLU makes it possible to bring together in the same modelling framework economic mechanisms subject to technical constraints (Souty et al. 2012). Unlike statistical models such as the CLUE-S model (Verburg et al. 2002) or a spatial econometrics model (Chakir & Le Gallo 2013), NLU represents relatively well the long-term processes and impacts of public policy on the agricultural system. ...
The large-scale implementation of emission reduction strategies in the agriculture, forestry and other land uses (AFOLU) sector raises questions about their sustainability. For example, second-generation bio-fuels threaten biodiversity and the reforestation of agricultural land increases food prices. In addition, these emission reduction strategies are highly dependent on socio-economic conditions describing the rest of the food system (agricultural trade liberalization, economic development, population growth, etc.). For example, an increase in food demand, due to population growth and economic development, can increase pressures on the food system, leading to ecosystem degradation and increased greenhouse gas emissions. In this thesis, we seek to clarify the impacts on biodiversity, food and greenhouse gas emission of large-scale mitigation strategies in the AFOLU sector under different socio-economic conditions. To do this, we used prospective modeling to simulate various global land uses in 2030, 2050 and 2100 under different scenarios. More specifically, to study the impact of different mitigation strategies on biodiversity indicators, we coupled the Nexus Land-Use (NLU) model with the Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (PREDICTS) biodiversity model. A nitrogen balance is also built to specify the link between intensification and environmental impact.In the first chapter, we assessed the impact of scenarios of increased legume production in Europe on greenhouse gas emissions in the AFOLU sector. We found that the main environmental benefit of legumes is to provide proteins as a substitute for animal products rather than enabling a lower consumption of synthetic fertilizer through the increased leguminous nitrogen fixation. Most of the emission reduction takes place in the animal production sector and outside Europe. This first chapter also highlights the importance of indirect mechanisms that lead to a reduction in N2O emissions associated with nitrogen fertilization in the plant sector. The sensitivity of these results to different reforestation scenario led me to then focus on the interactions between mitigation strategies.In the second chapter, we analyzed the trade-offs and synergies between biodiversity and food security for different combinations of mitigation scenarios. Large-scale bioenergy production had negative effects on different biodiversity indicators (species richness and biodiversity intactness index) as well as on different food security indicators (food prices and production costs). Although presenting a trade-off between biodiversity protection and food security, a combination of diet change and reforestation scenarios can improve biodiversity and food security in many cases compared to a situation without mitigation.In a third chapter, we identified global land-use scenarios that ensure to stay within planetary boundaries in terms of nitrogen cycle, biosphere integrity, non-CO2 emissions from the AFOLU sector and forest conservation. We showed that despite the uncertainty surrounding the determination of global boundaries, the most robust environmental scenarios that ensure to stay within these global boundaries are mainly composed of reforestation, dietary changes and increased efficiency in the use of inputs in crop production.
... Agribiom is a world food balance model which objectives were to help renewing analyses and debate on past and future consumption, production and trade in food biomass 10 . Its construction started in 2006 at CIRAD, to support two projects: Agrimonde, a French collective interdisciplinary scenario-building exercise on food and agriculture (Paillard et al., 2011); and Nexus Land-Use ( Souty et al., 2012), an integrated model of competition over land use between food and bioenergy ( Dorin et al., 2009a) within the general equilibrium framework of Imaclim-R ( Sassi et al., 2010). ...
Models of world agriculture and food systems are used widely to predict future scenarios of land and resource uses. Starting with a brief history of world agriculture models since the 1960s, which shows their hybrid character as well as their limitations in representing real world diversity and options, this article then presents an alternative modelling experience. We argue that models are tools of evidence, hence “truth machines”, but also tools of government, with a multi-faceted political dimension. For instance, the virtual realities that conventional models build incorporate value judgements about the future that remain invisible and difficult to challenge. For ease of computation and comparison, they standardise functional forms and parameters, eliding observable diversity and blacklisting sociotechnical policy options such as those based on agroecology and biological synergies. They are designed for prediction and prescription rather than for supporting public debate, which is also a (comfortable) political stance. In contrast, the Agrimonde experience – a foresight initiative based on the Agribiom model – shows that a model of world agriculture can be constructed as a “learning machine” that leaves room for a variety of scientific and stakeholder knowledge as well as public debate. This model and its partners unveiled some virtual realities, processes and actors that were invisible in mainstream models, and asserted a vision of sustainable agri-food systems by 2050. Agribiom and Agrimonde improved knowledge, policy-making and democracy. Overall, they highlighted the need for epistemic plurality and for engaging seriously in the production of models as learning machines.
... The marketmediated effects considered are (i) changes in yield due to input use and to expansion on marginal lands; (ii) changes in the production allocation among countries and sectors (crop and livestock); and (iii) changes in final demand. We then undertake a numerical analysis using the Nexus Land-Use (NLU) model (see Souty et al. (2012) and "NLU Short Description" section), which is a global partial equilibrium model of land-use combining biophysics and economics, for a scenario of biofuel scenario produced from rapeseed in Europe. The sensitivity of the dynamics of extensification and the potential of intensification is also assessed by testing a range of key model parameters. ...
... It does so by minimising the total production cost under a supply-use equilibrium on food and bioenergy markets. A detailed description can be found in Souty et al. (2012) or in Brunelle et al. (2015). Main model equations are also given in SI. ...
... To circumvent this problem, we represent the extensive margin using regional land distributions of potential yields 1 . These distributions are calculated by mapping the land-use dataset from Ramankutty et al. (2008) on the potential yields from the vegetation model LPJmL (see Souty et al. (2012) and SI for more details). They are used to model a Ricardian production frontier splitting agricultural lands into two parts: an intensive system, composed of a mosaic of crops and pastures, and an extensive system, exclusively composed of pastures. ...
Unravelling the dynamics of land-use change is key to assess the environmental and socioeconomic impacts of land-based strategies regarding climate or energy. In this prospect, this paper proposes an analytical decomposition of land-use change resulting from a shock in agricultural demand which takes into account indirect effects from price signals. This analytical equation is numerically estimated using a global model of land-use combining biophysics and economics. While being relatively simple, this model captures the main processes of land-use change: change in the intensive and extensive margins, international trade, change in intermediary demand and possible by-products. At the global scale, our results show that yield losses due to the conversion of marginal land amount approximately to half of yield gains due to fertiliser use. At the regional scale, patterns of yield and area responses are depicted by assessing the potentials for intensification (yield gaps) and extensification (areas of extensive pastures) given the future pathways of agricultural demand.
... CLUMondo (Conversion of Land Use on Mondial scale) is a spatial land system change model, where future changes to the landscape are driven by multiple demands (S2), such as Fig. 1 The study area with four thematic subregions crops, livestock, and built-up areas (van Asselen and Verburg 2013). The model goes beyond simulating land cover changes only, as land systems combine information on land management, fertilizer input, yield gap, and livestock numbers (Souty et al. 2012;van Asselen and Verburg 2013). The explicit representation of land management allows accounting for change in the intensity of production systems, for example, by improving yields or increasing livestock density (van Asselen and Verburg 2013). ...
Meeting the growing demand for food in the future will require adaptation of water and land management to future conditions. We studied the extent of different adaptation options to future global change in the Mediterranean region, under scenarios of water use and availability. We focused on the most significant adaptation options for semiarid regions: implementing irrigation, changes to cropland intensity, and diversification of cropland activities. We used Conversion of Land Use on Mondial Scale (CLUMondo), a global land system model, to simulate future change to land use and land cover, and land management. To take into account future global change, we followed global outlooks for future population and climate change, and crop and livestock demand. The results indicate that the level of irrigation efficiency improvement is an important determinant of potential changes in the intensity of rain-fed land systems. No or low irrigation efficiency improvements lead to a reduction in irrigated areas, accompanied with intensification and expansion of rain-fed cropping systems. When reducing water withdrawal, total crop production in intensive rain-fed systems would need to increase significantly: by 130% without improving the irrigation efficiency in irrigated systems and by 53% under conditions of the highest possible efficiency improvement. In all scenarios, traditional Mediterranean multifunctional land systems continue to play a significant role in food production, especially in hosting livestock. Our results indicate that significant improvements to irrigation efficiency with simultaneous increase in cropland productivity are needed to satisfy future demands for food in the region. The approach can be transferred to other similar regions with strong resource limitations in terms of land and water.
Electronic supplementary material
The online version of this article (10.1007/s11027-017-9761-0) contains supplementary material, which is available to authorized users.
... For the reference land use area distribution used in the base year 2011, croplands are produced by eight crop categories which contain 149 crop types (see ''Online Appendix Table A.5''). According to Food and Agriculture Organization (FAO) definition, grass is from permanent pastures and can be used to graze (Souty et al. 2012). Forest sector is divided into managed forests and no-managed forests. ...
A series of global actions have been made to address climate change. As a recent developed climate policy, Intended Nationally Determined Contributions (INDC) have renewed attention to the importance of exploring temperature rise levels lower than 2 °C, in particular a long-term limit of 1.5 °C, compared to the preindustrial level. Nonetheless, achieving the 2 °C target under the current INDCs depends on dynamic socioeconomic development pathways. Therefore, this study conducts an integrated assessment of INDCs by taking into account different Shared Socioeconomic Pathways (SSPs). To that end, the CEEP-BIT research community develops the China’s Climate Change Integrated Assessment Model (C³IAM) to assess the climate change under SSPs in the context of with and without INDCs. Three SSPs, including “a green growth strategy” (SSP1), “a more middle-of-the-road development pattern” (SSP2) and “further fragmentation between regions” (SSP3) form the focus of this study. Results show that after considering INDCs, mitigation costs become very low and they have no evident positive changes in three SSPs. In 2100, a temperature rise would occur in SSP1-3, which is 3.20, 3.48 and 3.59 °C, respectively. There are long-term difficulties to keep warming well below 2 °C and pursue efforts toward 1.5 °C target even under INDCs. A drastic reduction in greenhouse gas emissions is needed in order to mitigate potentially catastrophic climate change impacts. This work contributes on realizing the hard link between the earth and socioeconomic systems, as well as extending the economic models by coupling the global CGE model with the economic optimum growth model. In C³IAM, China’s energy consumption and emissions pattern are investigated and refined. This study can provide policy makers and the public a better understanding about pathways through which different scenarios could unfold toward 2100, highlights the real mitigation and adaption challenges faced by climate change and can lead to formulating effective policies.
