Regional impact of climate variability and adaptation options in the southern Murray–Darling Basin, Australia

Climate variability impacts differentially on irrigators depending on water availability and quality, climate, crop, and policy instruments such as water markets. Water policy directs available water allocations at a regional scale, while irrigators adapt via decisions about crop selection and water management, for example through deficit irrigation and adoption of water efficient technologies, respond via changes to water use at the farm and sectoral scale. Water markets allow these two scales to interact, in effect transferring water across regions and states. In this paper we used a positive mathematical programming model to examine the interacting impact of these two incremental adaptation options on regional water use and agriculture production for four climate variability states of nature across the Southern Murray-Darling Basin. Our results show the impacts of climate variability and the effectiveness of adaptation options that vary across regions. Our conclusions have implications for understanding regional difference in adjusting to climate variability.