Global Warming Threatens Vintners
National Science Foundation, NASA and Purdue U Report Suggests Wine-Growing Regions Reduced by 81% by 2100
Jul 12, 2006
Wine grapes are very particular when it comes to climate. A study released this week by the National Science Foundation, NASA, and Purdue University warned that if global warming trends continue at the present rate, present winegrowing regions could be reduced by as much as 81% by the end of the century.
All the major winegrowing regions of the world are located in a swath between 30°-50° north latitude (Europe, Middle East, China, the United States, and southern Canada) and 30°-50° south latitude (South Africa, South Australia, New Zealand, Chile, and Argentina). Winegrapes have not been successfully grown in equatorial or tropical regions.
Throughout much of Europe, the tiny microclimatic differences between adjoining vineyards can mean the difference between a $20 village wine and a $200 Grand Cru.
California's Napa Valley is divided into six identifiable climate regions with different grape varietals associated with each. Cool Carneros, near San Pablo Bay and designated Region I is planted largely to Chardonnay and Pinot Noir, while just a few miles north in Calistoga (Region VI) Cabernet Sauvignon dominates.
Even a single degree of temperature rise in the typically hot summer months can shut down photosynthesis and break down the chemical composition of the juice, according to Noah Diffenbaugh of the Department of Earth and Atmospheric Sciences at Indiana's Purdue University.
Winegrapes need consistent temperatures during the growing season and those used for premium wines almost always prefer cooler, rather than warmer climates. Grapes such as Pinot Noir and Riesling simply won't perform in even moderately warm regions. They are at home in cool coastal valleys and in specific cool microclimates like France's Burgundy slopes and Germany's Rhine River Valley. Distinctive regions like these could face extinction if the conclusions of this global warming study prove true.
According to Niels Udsen, owner of Paso Robles' Castoro Cellars, the effects of global warming have not yet been observed in the vineyard, but Diffenbaugh's study has raised many eyebrows and viticulturists are certain to take the issue very seriously in the years ahead.
The winegrapes that are most at risk include Nebbiolo (Barolo, Barbaresco), Pinot Noir, Tempranillo (Rioja), Chardonnay, Pinot Blanc, Pinot Grigio, Viognier, Roussanne, Riesling and Gewürztraminer. Sturdy winegrapes that can be grown successfully over a range of climatic conditions will be somewhat less affected. These would include Cabernet Sauvignon, Zinfandel, and Sauvignon Blanc.
