HR: 1340h
AN: A53B-0897    [Abstracts]
TI: Emissions Pathways, Climate Change, and Future Wine Grape Quality in California
AU: * Cahill, K N
EM: kncahill@stanford.edu
AF: Department of Global Ecology, Carnegie Institute of Washington, 260 Panama Street, Stanford, CA 94305 United States
AU: Field, C B
EM: cfield@globalecology.stanford.edu
AF: Department of Global Ecology, Carnegie Institute of Washington, 260 Panama Street, Stanford, CA 94305 United States
AU: Hayhoe, K
EM: hayhoe@atmosresearch.com
AF: ATMOS Research and Consulting, 809 West Colfax Avenue, South Bend, IN 46601 United States
AB: Grapes are the most valuable fruit crop in the nation, with wine grapes making up three-quarters of total grape value. California grows over 90% of wine grapes in the U.S., with an annual crop value of \$3.2 billion. Producing high-quality wine requires both human skill in vineyard management and winemaking, and environmental conditions suited to the optimal ripening of the grape on the vine. As wine grapes are long-lived perennial crops often in production for many decades, they are potentially sensitive to changes in climate. We used two state-of-the-art climate models (PCM and HadCM3), driven by scenarios of higher and lower greenhouse gas emissions (IPCC SRES scenarios A1fi and B1), to project climate in California over the coming century. Projected temperatures were used to estimate 1) wine grape ripening time based on accumulated growing degree days, and 2) average monthly temperature at ripening, a factor influencing potential quality. Ripening temperature ranges were designated as optimal, marginal, or impaired for producing high-quality wine grapes. For the top ten grape-growing counties in California, we compared modeled temperature averages for mid-century (2020-2049) and end-of-century (2070-2099) to a baseline of modeled growing degree day accumulation and observed average temperatures from weather stations. Across all models and scenarios, earlier ripening at higher temperatures produced shifts from optimal to marginal or impaired conditions across major grape-growing regions in the state by the end-of-century, with the notable exception of the cool coastal counties of Monterey and Mendocino. Some differences are apparent between higher and lower emissions scenarios between models. Significant adjustments may be required to adapt wine grape varieties, management, and growing regions to a changing climate over the coming century, and the magnitude of these adjustments could be affected by the emissions pathway followed during that time.
UR: http://www.pnas.org/cgi/content/abstract/0404500101
DE: 1600 GLOBAL CHANGE (New category)
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 0614 Biological effects
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting