Classifying Climate-Suitable Lands in California for Coffee Cultivation

Increased market for specialty coffee and climate volatility in traditional coffee-growing regions of the world has prompted interest in cultivating coffee outside of the tropics, including in California. While several small coffee farms have established in California over the past couple decade, no studies have identified and quantified climatically suitable regions for growing coffee. We developed a model of Coffea arabica suitability based on agronomic studies of thermal constraints to coffee cultivation, combining heat and cold intolerance with energy requirements for maturation. This model was applied to agricultural lands across California using high-resolution climate datasets for both modern (1991–2020) and projected near-term (2021–2050) conditions. We explored the potential for farm thermal management approaches—such as using agroforestry shade trees—to buffer temperature extremes and augment thermal suitability. Results indicate that, in the absence of thermal management approaches, nearly all agricultural lands in the state experience temperature extremes detrimental to coffee cultivation in modern climate. By contrast, we found that over 230 km² of agricultural land in coastal southern and central California is thermally suitable for coffee with management efforts. These suitable areas include most of the state's avocado cultivation—which may serve as a thermal buffer for coffee and favour the environmental and economic agricultural sustainability of this coupled crop system. We additionally show that projected near-term climate coupled with management efforts leads to moderate increases in thermally suitable agricultural lands for coffee cultivation. Despite numerous economic and logistical challenges, that impede the growth of a burgeoning coffee region in coastal, southern and central California, we demonstrate that climate conditions in both today and in the future, combined with agronomic management efforts such as shading, provide an opportunity for a viable coffee production in California.