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Agricultural commodity prices have increased since the early 2000s in response to a combination of causes on the demand side (demographic growth, increased animal product consumption in emerging countries and biofuel mandates) and on the supply side (the phasing out of agricultural policies subsidising food supply in the European Union and United States, lack of public investment in agriculture, reaching ceilings in cereal yields in already high-yield countries and an increase in energy prices). The succession of food crises between 2008 and 2012 has brought the agricultural price regime and its implications for food security back to the forefront. Even though the increase of average agricultural prices could profit some farmers, part of the price increase corresponds to increased costs and urban dwellers, as well as many food-insecure food producers, depend on the market for their supply. In addition, environmental policies concerning the protection of biodiversity, climate mitigation and pesticide reduction could make these issues even more acute.

Globalization drives a process of diet convergence among developing and developed countries that challenges the predictions about future patterns of food consumption. To address this issue, the objective of this article is to map the range of the possible future diet changes and to explore their impact on agriculture using the Nexus Land-Use model. This model computes agricultural intensification in the crop and livestock sectors at the global scale, based on an architecture accounting for the different types of food calories. By considering four scenarios built on distinct assumptions regarding diet convergence, this article sheds light on the pivotal role of diet changes as drivers of tensions on agriculture and land use and shows the uncertainty associated with processes of diet convergence for foresight exercises on food and agriculture. Finally, the interactions between food production and the other land-use patterns are explored by testing the sensitivity of our results to assumptions regarding biofuel production, deforestation, potential crop yields, and nutrient-use efficiency.

Competition between direct consumption of plant production and the feeding of livestock is key to global food availability. This is because livestock consume edible commodities that could be available for (food insecure) populations but also because it diverts arable land from food production. The share of total plant production redirected towards feeding livestock is (roughly) known but estimations of land surfaces virtually occupied by livestock production are scarce. In this study, following up on the Agrimonde Terra** project, we estimate areas devoted to the feeding livestock. First, we estimate the protein composition of an averaged feed basket at the global scale in 2005 and detail the evolution of the protein-source feed component during the period 1961–2009. We focus on protein-rich crops such as oil crops and show its proportion in the global livestock diets has tripled since 1960, though only accounting for about one fourth of total proteins. Then, we estimate land virtually occupied by crop feed at the global scale using a set of straightforward hypotheses. Our estimates suggest that, although livestock and feed production has continuously increased and despite uncertainties in available data, competition for land between feed and food uses has decreased over the last two decades. The share of areas cultivated for feed requirements decreased from about 50% in the 1970s to 37% nowadays. This trend is attributable to the increase of crop yields and to a decrease of the share of cereals in livestock diets to the benefit of oilseeds by-products. However, estimating the share of total areas used for feed is complicated by the significant role played by by-products.

This paper presents a modeling framework for macroeconomic growth dynamics; it is motivated by recent attempts to formulate and study \integrated models" of the coupling between natural and socio-economic phenomena. The challenge is to describe the interfaces between human activities and the functioning of the earth system. We examine the way that this interface works in the presence of endogenous business cycle dynamics, based on a non-equilibrium dynamic model. Recent findings about the macroeconomic response to natural disasters in such a non-equilibrium setting have shown a more severe response to natural disasters during expansions than during recessions. These findings raise questions about the assessment of climate change damages or natural disaster losses that are based purely on long-term growth models. In order to compare the theoretical findings with observational data, we analyze cyclic behavior in the U.S. economy, based on multivariate singular spectrum analysis. We analyze a total of nine aggregate indicators in a 52-year interval (1954{2005) and demonstrate that the behavior of the U.S. economy changes significantly between intervals of growth and recession, with higher volatility during expansions.

We apply multivariate singular spectrum analysis to the study of US business cycle dynamics. This method provides a robust way to identify and reconstruct oscillations, whether intermittent or modulated. We show such oscillations to be associated with comovements across the entire economy. The problem of spurious cycles generated by the use of detrending filters is addressed and we present a Monte Carlo test to extract significant oscillations. The behavior of the US economy is shown to change significantly from one phase of the business cycle to another: the recession phase is dominated by a five-year mode, while the expansion phase exhibits more complex dynamics, with higher-frequency modes coming into play. We show that the variations so identified cannot be generated by random shocks alone, as assumed in "real" business-cycle models, and that endogenous, deterministically generated variability has to be involved.

How will future changes in land uses - within regions and on a global level – will affect food security, taking into account possible climate changes, as well as changes in cropping and livestock systems, changes in farm structures, rural and urban relations, food regimes as well as changes in the general context. The agrimonde- terra foresight project on "L and use and food (in) security" considers this question. Launched by the French research institutes Cirad and inra , the agrimonde- terra conceptual framework can be used to build land uses scenarios at national and global levels with narratives and quantitative illustrations. a t national and regional levels, the foresight process involves a group of diverse stakeholders, and discussions on the direct and indirect causes of land use changes facilitate thinking about the possible futures (anticipation), getting new ideas and understanding different points of view (appropriation) as well as decision-making (action). A first workshop has taken place in Tunisia and land use scenarios have been built. On top of that, global and regional levels scenarios are built with the support of a scenarios advisory Committee and their are the basis for discussions on possible consequences of land use changes on food security. t he scenarios have been build combining hypotheses on direct and indirect causes of land use changes, and looking at interactions and retroactions between the variables. The foresight exercice has a wholistic approach. Climate change is one of the important indirect drivers of land use changes. It impacts the food production capacity of ecosystems in several ways. i t changes the time maturity of crops, it alters annual yields as well as their inter-annual variability, and it changes the nutritious qualities of crops. a s far as climate change is concerned, two contrasted scenarios have been taken into account, focusing on temperature change and biogeochemical cycles. t he first scenario, entitled "Stabilization of Global Warming" corresponds to the RCP 26 the AR5.The agricultural system does not experience any major change due to climate conditions compared to the current situation. t he area of cropland suitable for agricultural production does not notably change compared to the current situation, but the stabilization of anthropogenic emissions requires massive efforts for sequestering carbon in the vegetation which may take the form of afforestation and/or production of bioenergy production with carbon capture and storage, or agro-forestry. Most of the land use changes, however, occur after 2050. t he second scenario entitled " runaway climate change" corresponds to the RCP 85 of the AR5. The agricultural system experiences strong impacts: there are increases in the area of cropland suitable for agricultural production but it is unevenly allocated as it mainly concerns the northern latitudes while arable cropland areas decrease in tropical regions. The average suitability of cropland areas also decrease significantly. t he combination of the climate change scenarios with scenarios concerning the direct and indirect causes of land use changes show that food regimes, crooping and livestock systems, and farm structures, will have to adapt to new situations (Texte intégral)

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.

By 2050, the agricultural sector should produce food to feed an increased and wealthier population, while reducing environmental impacts. In particular, conversion of natural ecosystems and greenhouse gas emissions are serious potential impacts of agricultural production. To take up this challenge, many options exist for the agricultural sector. Some are on the supply side, such as increasing the efficiency of livestock production, increasing the efficiency in crop production inputs, or a sustainable increase of aquaculture. Others are on the demand side, such as changes in diets, reduction of losses and wastes or, more controversially, reduction in population increase. The overall consequences of those options on land-use and greenhouse gas emissions, especially when taken together, are not easy to assess in a transparent and consistent way. To tackle this challenge, a simple balance model with detailed biophysical modules is developped to assess the consequences in term of greeenhouse gases emissions reductions of various options for the agricultural sector, under the constraint of feeding the world. The reference year balances are based on FAOSTAT food commodity balances. Demand is set exogenously based on population and diets, trade is based on import dependence and export market shares, and loss coefficients are used. Transformation through livestock sectors and oil crops crushing allows to determine production, and, with exogenously set yields, land-use. In the reference case, yields and demands evolutions are based on FAO projections. Detailed modules of livestock, aquaculture, land-use change emissions, nitrogen cycle and rice methane emissions allow to determine transformation and emission coefficients, as well as the consequences of diverse options. The model integrates those informations at the global scale on several regions, allowing to assess in a transparent way the consequences of the options used together. The methodology and the model results will be presented for change in livestock efficiency, rice methane emissions mitigation options, changes in diets and increases in nitrogen use efficiency. (Texte intégral)

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.

International audience ; This paper is motivated by the rising interest in assessing the effect of disruptions in resources and environmental conditions on economic growth. Such an assessment requires, ultimately, the use of truly integrated models of the climate and economic systems. For these purposes, we have developed a Non-Equilibrium Dynamic Model (NEDyM) by introducing investment dynamics and nonequilibrium effects into a Solow growth model. NEDyM can reproduce various economic regimes, such as manager- or shareholder-driven economies, and permits one to examine the effects of disruptions on the economy, given either an assumption of steady-state growth or an assumption of business cycles with transient disequilibrium. We have applied NEDyM to an idealized economy that resembles in certain respects the 15-state European Union in 2001. The key parameter in NEDyM is investment flexibility. For certain values of this parameter, the model reproduces classical business cycles with realistic characteristics; in particular, NEDyM captures the cycles' asymmetry, with a longer growth phase and more rapid contraction. The cyclical behavior is due to the investment­ profit instability and is constrained by the increase in labor costs and the inertia of production capacity. For somewhat greater investment flexibility, the model exhibits chaotic behavior, because a new constraint intervenes, namely limited investment capacity. The preliminary results presented here show that complex behavior in the economic system may be due entirely, or at least largely, to deterministic, intrinsic factors, even if the economic long-term equilibrium is neo-classical in nature. In the chaotic regime, moreover, slight shocks ­ such as those due to natural or man-made catastrophes ­ may lead to significant changes in the economic system.