From an IPCC document …Wine and recent warming
Wine-grapes are known to be highly sensitive to climatic conditions, especially temperature (e.g., viticulture was thriving in England during the last medieval warm period). They have been used as an indicator of observed changes in agriculture related to warming trends, particularly in Europe and in some areas of North America. In Alsace, France, the number of days with a mean daily temperature above 10°C (favourable for vine activity) has increased
from 170 around 1970 to 210 at the end of the 20th century (Duchêne and Schneider, 2005). An increase associated with a lower year-to-year variability in the last 15 years of the heliothermal index of Huglin (Seguin et al., 2004) has been observed for all the wine-producing areas of France, documenting favourable conditions for wine, in terms of both quality and stability. Similar trends in the average growing-season temperatures (April-October for the Northern Hemisphere) have been observed at the main sites of viticultural production in Europe (Jones, 2005). The same tendencies have also been found in the
California, Oregon and Washington vineyards of the USA (Nemani et al., 2001; Jones, 2005).
The consequences of warming are already detectable in wine quality, as shown by Duchêne and Schneider (2005), with a gradual increase in the potential alcohol levels at harvest for Riesling in Alsace of nearly 2% volume in the last 30 years. On a worldwide scale, for 25 of the 30 analysed regions, increasing trends of vintage ratings (average rise of 13.3 points on a 100-point scale for every 1°C warmer during the growing season), with lower vintage-to-vintage variation, has been established (Jones, 2005).
Let's have a special toast to all of the human folly that has given us global warming. It wasn't all totally bad.