Bordeaux In America Symposium
Climate change —How do winegrowers maintain the historical relationship between a great appellation and price if temperature is predicted to rise within the lifetime of the next major replanting of Cabernet Sauvignon?
THE QUEST RESULTS FROM THE TRIGGER WE CANNOT CONTROL: THE “PERFECT” TEMPERATURE — The benchmark for Cabernet Sauvignon is arguably 17.5±1.5º C. By the end of the 20th century, Growing Season Temperature (GST) in Cabernet wine country warmed 1.2ºC in 50-years. In 1997, GST in St. Helena peaked at 20.4ºC — pushing St. Helena into a University of California Winkler Index IV for that season, considered by many to be too hot for Burgundian varieites—chardonnay and pinot noir.
ONE SURPRISE INVOLVES THE PACIFIC OCEAN. Which is producing asymmetric changes. Sea Surface Temperature (SST) at 35º N Latitude is correlated in the statistical plots of all temperature indices: SST annual average increase is 0.7ºC. Growing Season Temperature (GST) increased 0.8ºC in St. Helena from the decade 1951-1960 (18.5ºC) to 1991-2000 (19.3ºC). The surprise is most of the change occurred at night: 1951-1960 (9.1ºC) to 1991-2000 (10.5ºC), the magnitude is much larger 1.4ºC. There are other surprises: By example most of the year over year increases in seasonal temperature occur in Spring. What is the effect of asymmetric change on phenology: bud break, florasion, verasion and harvest. For the period 1951 to 2000 bud break was advance 18 to 24 days. What are the best Global Climate Models (GCMs) for winegrowers to use in California?
A SECOND SURPRISE IS PHENOLOGY is decoupling from temperature, and how? It is no longer possible to predict harvest dates as was possible before climate change. Other surprises include changes the color, flavor and fragrance of wines.
THE CRITICAL CHOICES: A “business as usual” approach to framing Climate Change by the winegrowing community is insufficient to support all the required planning to produce resilient Bordeaux vineyards in every appellation. This conference sets the quest for winegrowers who choose to stay and farm. How do I install a high performance vineyard in 2020 that survives to 2050? What are the different choices for Paso Robles and elsewhere? What cultural farming practices will need to change? Our quest is set to answer the ultimate question for winemakers: How to make Cabernet Sauvignon blend wines as average GST crosses 19ºC?
JOIN US FOR BORDEAUX IN AMERICA: THE CLIMATE DISRUPTION — The leader in climate change domain knowledge for Bordeaux vintners in the Napa Valley.