Assessing Crop Vulnerability to Climate Change: A Southwest Perspective.

The USDA Southwest Regional Climate Hub is one of ten Climate Hubs and Sub-hubs established in 2014. The Hub region includes Arizona, California (partnering with the California Sub-Hub), Nevada, New Mexico and Utah.  Beyond the mainland States, the SW hub also serves Hawaii and the US affiliated Pacific Islands. The Hub's primary mission is to deliver science-based knowledge and practical information to farmers, ranchers and forest landowners to help them adapt to changing environmental conditions. One of the recent activities of the hub was to review climate change impacts on Southwestern agriculture, with a specific focus on vulnerability. In considering vulnerability, we reviewed factors relating to (i) exposure of systems to the impacts of climate change, (ii) the inherent ability of systems to withstand exposure to the changing climate and (iii) adaptive capacity. In this presentation, we highlight some of the key findings from our review of regional vulnerabilities and we discuss a potential framework for vulnerability assessment of southwestern cropping systems. If vulnerability is a function of exposure, sensitivity, and adaptive capacity then in quantifying vulnerability, it is essential to recognize how these factors combine and interact at different scales within the system. For example at the scale of an individual crop, we can assess how changes in yield are affected by rising temperatures or drought, how sensitive the crop is to temperature or drought stress, and what potential adaptations might be practical at the scale of the crop (e.g., changing sowing dates, using different crop cultivars etc.) An alternative but complimentary approach is to assess contextual vulnerability, which incorporates the socio-political and economic context alongside climate change in evaluating the security of a human system (such as a farm, farming community or regional economy).