Search for: All records

Abstract Climate change poses growing risks to global agriculture including perennial tree fruit such as apples that hold important nutritional, cultural, and economic value. This study quantifies historical trends in climate metrics affecting apple growth, production, and quality, which remain understudied. Utilizing the high-resolution gridMET dataset, we analyzed trends (1979–2022) in several key metrics across the U.S.—cold degree days, chill portions, last day of spring frost, growing degree days (GDD), extreme heat days (daily maximum temperature >34 °C), and warm nights (daily minimum temperatures >15 °C). We found significant trends across large parts of the U.S. in all metrics, with the spatial patterns consistent with pronounced warming across the western states in summer and winter. Yakima County, WA, Kent County, MI, Wayne County, NY—leading apple-producers—showed significant decreasing trends in cold degree days and increasing trends in GDD and warm fall nights. Yakima county, with over 48 870 acres of apple orchards, showed significant changes in five of the six metrics—earlier last day of spring frost, fewer cold degree days, increasing GDD over the overall growth period, and more extreme heat days and warm nights. These trends could negatively affect apple production by reducing the dormancy period, altering bloom timing, increasing sunburn risk, and diminishing apple appearance and quality. Large parts of the U.S. experience detrimental trends in multiple metrics simultaneously that indicate the potential for compounding negative impacts on the production and quality of apples and other tree fruit, emphasizing the need for developing and adopting adaptation strategies. 

Abstract Aligning water supply with demand is a challenge, particularly in areas with large seasonal variation in precipitation and those dominated by winter precipitation. Climate change is expected to exacerbate this challenge, increasing the need for long‐term planning. Long‐term projections of water supply and demand that can aid planning are mostly published as agency reports, which are directly relevant to decision‐making but less likely to inform future research. We present 20‐year water supply and demand projections for the Columbia River, produced in partnership with the Washington State Dept. of Ecology. This effort includes integrated modeling of future surface water supply and agricultural demand by 2040 and analyses of future groundwater trends, residential demand, instream flow deficits, and curtailment. We found that shifting timing in water supply could leave many eastern Washington watersheds unable to meet late‐season out‐of‐stream demands. Increasing agricultural or residential demands in watersheds could exacerbate these late‐season vulnerabilities, and curtailments could become more common for rivers with federal or state instream flow rules. Groundwater trends are mostly declining, leaving watersheds more vulnerable to surface water supply or demand changes. Both our modeling framework and agency partnership can serve as an example for other long‐term efforts that aim to provide insights for water management in a changing climate elsewhere around the world.