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Dissertation zugänglich unter
Water, agriculture and climate change: a global computable general equilibrium analysis
Wasser, Landwirtschaft und Klimawandel: eine globale allgemeine Gleichgewichtsanalyse
Calzadilla Rivera, Alvaro Luis
Dokument 1.pdf (3.813 KB)
Freie Schlagwörter (Englisch):
Computable General Equilibrium , Climate Change , Agriculture , Water resources , Water Policy
83.63 , 83.66
Natürliche Ressourcen, Energie und Umwelt
Tol, Richard S.J. (Prof. Dr.)
Tag der mündlichen Prüfung:
Kurzfassung auf Englisch:
Based on the global general equilibrium model GTAP-W, this thesis aims to study the role of water resources in agriculture and within the context of international trade. The first paper of the thesis introduces the GTAP-W model. In the next four papers different water management policies dealing with water scarcity, sustainability and climate change are analyzed.
The first paper “The GTAP-W Model: Accounting for Water Use in Agriculture” is a technical description of the new data and features of the model. After surveying some existing CGE models that account for water use, this paper introduces the GTAP-W model, describing in detail the new data on production, area and water use in rainfed and irrigated crops and the corresponding land and irrigation rents. The new production structure of the model is described, giving special emphasis on its implementation and changes to the code. Before implementing concrete policy analysis, a comprehensive validation of the model is performed, concluding to a satisfactory robustness of the model.
The second paper “Water Scarcity and the Impact of Improved Irrigation Management” analyzes if improvements in irrigation efficiency worldwide would be economically beneficial for the world as a whole as well as for individual countries and whether and to what extent water savings could be achieved. Currently, less than 60 percent of all the water used for irrigation is effectively consumed by crops. Therefore, we evaluate three scenarios showing a gradual convergence to higher levels of irrigation efficiency. We attempt to study potential global water savings, improving irrigation efficiency to the maximum attainable level.
In “The Economic Impact of more Sustainable Water Use in Agriculture”, we analyze potential impacts on trade and welfare of future projections of allowable water withdrawals for surface and groundwater based on two alternative water management scenarios in 2025. The first scenario explores a deterioration of current trends and policies in the water sector (water crisis scenario), while the second scenario assumes an improvement in policies and trends in the water sector and eliminates groundwater overdraft worldwide, increasing water allocation for the environment (sustainable water use scenario). This paper focuses on the role of green (effective rainfall) and blue (irrigation) water resources in agriculture.
In the fourth paper “Climate Change Impacts on Global Agriculture” we use predicted changes in the magnitude and distribution of global precipitation, temperature and river flow to assess potential impacts of climate change and CO2 fertilization on global agriculture. The analysis is carried out at two time periods (medium-term 2020s and long-term 2050s) and under two IPCC SRES scenarios (A1B and A2). The paper emphasizes the importance of differentiate between rainfed and irrigated agriculture, because both face different climate risk levels.
While the fourth paper focuses on climate change impacts, the fifth paper “Economywide Impacts of Climate Change on Agriculture in Sub-Saharan Africa” evaluates the efficacy of two scenarios as adaptation measures to cope with climate change in Sub-Saharan Africa. In the first adaptation scenario, irrigated areas in Sub-Saharan Africa are doubled by 2050, but total crop area remains constant. In the second adaptation scenario, both rainfed and irrigated crop yields are increased by 25 percent. Both adaptation scenarios are analyzed with IMPACT and GTAP-W, combining in this way the advantages of a partial equilibrium approach, which considers detailed water-agriculture linkages, with a general equilibrium approach, which takes into account linkages between agriculture and non-agricultural sectors and includes a full treatment of factor markets.