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Understanding climate-cropland interactions and their impact on future projections in West Africa motivated the recent development of a modeling framework that asynchronously couples four models for regional climate, crop growth, socioeconomics, and cropland allocation. This modeling framework can be applied to a future time slice using an equilibrium approach or to a continuous projection using a transient approach. This paper compares the differences between these two approaches, examines the transient dynamics of the system, and evaluates its impact on future projections. During the course of projection up to mid-century, food demand is projected to increase monotonically, while the projected crop yield shows a high degree of temporal dynamics due to strong climate variability. Such temporal dynamics are not accounted for by the equilibrium approach. As a result, the transient approach projects a generally faster future expansion of cropland, with the largest differences over Benin, Burkina Faso, Ghana, Senegal, and Togo. Despite the relative large differences between the two approaches in projecting land cover changes associated with cropland expansion, the projected future climate changes are fairly similar. While the additional cropland expansion in the transient approach favors a wet signal, both the transient and equilibrium approaches project a future decrease of rainfall in the western part of West Africa and an increase in the eastern part. For quantifying climate changes, the equilibrium application of the modeling framework is likely to be sufficient; for assessing climate impact on agricultural sectors and devising mitigation and adaptation strategies, transient dynamics is important. [ABSTRACT FROM AUTHOR]

ABSTRACT Aim This paper identifies socio-economic driving forces of biodiversity change and analyses their political and economic dynamics by modelling socio-economic parts of three scenario storylines developed for the ALARM (assessing large-scale risks for biodiversity with tested methods) project. In the BAMBU (business-as-might-be-usual) scenario policy decisions already made in the European Union (EU) are implemented and enforced, but no additional measures are introduced. The GRAS (growth applied strategy) scenario describes a future world orientated towards economic growth and complete deregulation. And finally, SEDG (sustainable European development goal) is a normative scenario focusing on the achievement of sustainable development. Methods The GINFORS (global inter-industry forecasting system) model is applied to quantify the effects of different sets of policy measures representing the three scenarios. It allows investigation of the inter-relations between socio-economic driving forces and the state of the environment. Results The presented results for the 25 EU countries focus on the following variables: unemployment, material extraction, energy supply and CO2 emissions. The lowest amount of unemployment is in the SEDG scenario, where it steadily decreases from 2005 to 2020. In BAMBU it falls to a level that is also below that of 2005. In GRAS, the number of unemployed people in 2020 is clearly over the value of 2005. The development of total material extraction from 2005 to 2020 is nearly stable in BAMBU, while it clearly increases in GRAS. Only in SEDG is there a reduction in resource use. None of the scenarios achieves a substantial reduction in energy use. However, the development of CO2 emissions shows a decoupling from energy supply. For BAMBU there is a slight decline in CO2 emissions over time, for GRAS they increase but with a slightly smaller growth rate than energy supply. In SEDG the emissions are reduced. The decoupling trends can be explained by a shift to more renewable energy sources in all scenarios, with the highest share in SEDG. Main conclusions The results indicate that a growth-oriented policy design, such as presented in the GRAS scenario, is not compatible with the conservation of biodiversity. Only in the SEDG scenario do the policy measures support the idea of a sustainable development, but in some respects they are still not ambitious enough. [ABSTRACT FROM AUTHOR]