Why well yield matters for managing agricultural drought risk

Groundwater-fed irrigation has supported growth in agricultural production around the world by allowing farmers to buffer production against the risks associated with variable and uncertain climatic conditions. However, uncontrolled exploitation has also led to rapid rates of groundwater depletion in many semi-arid and arid regions that threaten farmers' long-term capacity to adapt to future climate change and extreme events. Declining well yields, which control the potential rate and feasibility of groundwater abstraction, are likely to restrict adaptation to drought, but this interaction has largely been neglected in previous research. In this study, we present a set of numerical hydro-economic simulations that assess the joint biophysical and economic effects of climate variability and well yield on irrigated agriculture through a case study in the Texas High Plains region of the United States. Our results demonstrate that reductions in well yield will constrain farmers' ability to use irrigation as an adaptive tool, and may have large negative economic impacts on production. Significantly, economic impacts will be greatest during drought events that are projected to increase in frequency and intensity as a result of climate change. We suggest therefore that management of well yields should be a key consideration when evaluating agricultural drought risk adaptation. & 2015 Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).