ABSTRACT
Drought is an episodic phenomenon occurring in temperate zones and drylands and initially characterized by a decrease in rainfall with consequent reduction in availability of water in quantity and quality. Beginning as a regional hydrological drought due to the linkages of availability of water to environmental, social, and economic sectors, water quantity reduction manifests as agricultural and institutional drought. Global climate change increases the intensity and duration of extreme weather conditions, including droughts. There is a risk of prolonged regional drought conditions, leading to desertification with tragic consequences on human populations. The impacts of drought on human support structures may be mitigated by actions on a regional scale. The processes of understanding of the critical factors characterizing drought conditions 462and effecting rational changes in behavior may be cast in a risk-assessment and management framework. System dynamics modeling is a highly effective tool for elucidating and understanding key drivers of change in regions impacted by drought. Seeing the drought phenomenon as a set of factors, each linked to others in a causal manner, such a model may be constructed to represent causes and consequences of changes in human welfare in the drought-impacted region. This chapter describes drought-prone regions as systems consisting of interlinked environmental, social, and economic factors. It explores methods of using system dynamics modeling to understand current situations and inform management actions with the purpose of sustainable harvesting and renewing of resources for the viability of human populations and avoiding catastrophic desertification of these regions. A published case study is explored as demonstration of the power of system dynamics modeling in drought event scenario assessment.
