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Abstract

Drought and flood are commonly natural disasters, and found to alternate rapidly, which brings adverse impacts on agricultural production, ecosystem and economic development. Exploring drought-flood disaster risk plays a crucial role in water resources management and agricultural development in a changing climate, especially in semi-arid regions. However, the evolution characteristics of drought-flood disaster risk in the context of climate change remain poorly understood, and the corresponding mechanism are rarely discussed. To this end, a drought-flood disaster risk framework is constructed to explore its dynamic evolution. Firstly, drought and flood disasters are identified on the basis of historical observations and climate model simulations. Secondly, drought-flood disaster risk influenced by climate change and human activities is defined according to the disaster risk assessment mechanism, and its spatiotemporal evolution characteristics and future trend variability are also explored. Finally, the possible driving factors of drought-flood disaster are discussed. A study case of Gansu province, a typical semi-arid region in northwest China shows the following results: (1) drought-flood disasters are projected to be more frequent with intensified magnitude; (2) drought-flood disaster risk enhances under higher shared socioeconomic pathways and representative concentration pathways; (3) human activities play two-sided role in drought-flood disaster risk reduction, for example, water conservancy projects can effectively alleviate drought-flood disaster risk. Furthermore, measures for drought-flood disaster prevention and key strategies for drought-flood disaster risk reduction in Gansu are also put forward. Our findings may help policymakers develop suitable disaster mitigation plans for reducing the potential risks of water-related hazards in semi-arid regions.