A hydro-economic analysis of end-of-century climate projections on agricultural land and water use, production, and revenues in the U.S. Northern Rockies and Great Plains

Study region,Montana, U.S.A. Study focus Creating adaptation plans for projected imbalances in the western U.S. agricultural water demand-supply system are difficult given uncertainty in climate projections. It is critical to understand the uncertainties and vulnerabilities of the regional agricultural system and hydrologic impacts of climate change adaptation. We applied a stochastic, integrated hydro-economic model that simulates land and water allocations to analyse Montana farmer adaptations to a range of projected climate conditions and the response of the hydrologic system to those adaptations. Satellite observations of crop types, productivity, water use, and land allocation were used for model calibration. A suite of climate models was employed to quantify end-of-century impacts on streamflows, water and land use, production, and net revenues.New hydrological insights for the region Simulations showed summer streamflows were influenced by a state-wide 18.2% increase in agricultural water use. Decreased summer water availability with increased demand could have far reaching impacts downstream. Land use for irrigated crops increased 1.6%, while rainfed crops decreased 6.5%, implying state-level decrease in planted area. Even with increased land and water use for irrigated crops, production decreased 0.5%, while rainfed production decreased 2.7%. Corresponding losses in net revenues totaled 1.5% and 7.2% for irrigated and rainfed crops, respectively.Results highlight vulnerabilities of semi-arid agricultural regions and can aid water managers in sustaining agriculture in these regions.