Abstract

This interdisciplinary document is intended to build awareness about the urgent need to develop mitigation and adaptation strategies to climate change for specific agricultural regions. It addresses planning issues at both the farm and landscape levels, using a process that has engaged stakeholders.

Three storylines for potential responses in Yolo County, California, to climate change during the period 2010– 2050 differ mainly in decision-making approaches rather than climate regimes: [high growth (Intergovernmental Panel for Climate Change A2 – high greenhouse gas emission scenario); more sustainable (Intergovernmental Panel for Climate Change B1 - lower greenhouse gas emission scenario); and most precautionary (AB 32-Plus scenario)]. Crop shifts are expected, such as replacement of warm-season horticultural crops to hot-season crops. Without explicit breeding programs, grains, walnuts, and almonds will decline or at very best, slightly increase. Greater crop diversification is possible in Yolo County and will likely increase adaptation to climate change. Promising management options for mitigating greenhouse gas emissions are using less nitrogen fertilizer and farmscaping with woody perennials; both options require research and development. Yolo County's water supply may see little change under the B1 and AB 32-Plus scenarios, based on current models for 2010–2050, but agricultural water will decrease with urban demand in the A2 scenario. Reduced Sierra snowpack will increase flooding along the Sacramento River, presenting serious economic and ecological tradeoffs for ecosystem restoration versus farming. Not all California counties will experience the same agricultural vulnerabilities to climate change as Yolo County, but this approach to assessing mitigation and adaptation potential could be useful elsewhere. Vigorous planning strategies are immediately needed to reduce vulnerabilities and to increase mitigation and adaptation, so that preservation of California's agricultural lands will continue.