Modeling climate change impacts on agricultural water demand and productivity

• Main Author: Becker, Rike
• Format: Others
• Language: en
• Published: 2021
• Online Access: https://tuprints.ulb.tu-darmstadt.de/18586/1/Dissertation_Rike_Becker.pdf; Becker, Rike <http://tuprints.ulb.tu-darmstadt.de/view/person/Becker=3ARike=3A=3A.html> (2021): Modeling climate change impacts on agricultural water demand and productivity. (Publisher's Version)Darmstadt, Technische Universität, [Ph.D. Thesis]

Climate change and variability threatens the sustainability of future food production as well as the sustainability of water availability, especially in semi-arid regions where water resources are limited, and irrigated agriculture is widespread. Increasing temperatures will exacerbate evaporative losses and increase plant water needs. Consequently, higher irrigation intensities would be a logical measure to mitigate climate change impacts in these regions. But are increasing irrigation intensities truly the right adaption measure and can they help to reduce climate change induced agricultural production losses? To address this question, this PhD thesis investigates climate change impacts on agricultural productivity as well as changes in agricultural water demand using the agro-hydrological Soil & Water Assessment Tool (SWAT) and the bio-physical Agricultural Production Systems Simulator (APSIM). The study area, where the research is conducted, encompasses the intensively irrigated region of the Lower Chenab Canal System in Pakistan (15 000 km2), which is part of the Indus River irrigation system, the largest irrigation system in the world; and covers economically important crop growing areas. The results of this thesis reveal that agricultural productivity is highly affected by climate change and productivity levels are projected to decrease significantly. It could furthermore be shown that an intensification of irrigation might fail as a measure to counteract climate change, due to severe negative impacts of temperature stress on plant growth. To mitigate climate change impacts, the reductions of crop heat stress should therefore be prioritized in near future, while a more sustainable water management is unquestionable to continue to fulfill the high water demands in the long-term future.