What are your views on climate change, higher temperatures, pollution clouds and grape-growing/wine-making? Will wine regions have to be geographically redefined as a result?
Answer From Expert Roger Bohmrich MW
It's great to receive a question about the impact of climate change and wine, a complex and fascinating issue. It is very important to bear in mind that, while rising temperatures may be part of a changing climate, there are many other components, and it is the long-term trend which counts rather than weather anomalies in any one month or year. Wine is after all an agricultural product, and like other plants grape vines are inherently sensitive to the effects of climate. Even small changes in precipitation or temperature, for example, may have significant effects on budding, flowering and fruit production. Each grape variety has its own natural range of growing season temperatures, which in large measure determines the habitat or region where that variety will perform best. Over the 20th century, there has been a well-documented warming trend in many regions, yet the increase and related impacts are not universal and tend to be at their greatest in certain parts of the Northern Hemisphere. In practical terms, this has translated to an advance in the growth cycle: Harvests in Bordeaux or the Southern Rhône Valley are much earlier than they were, on average, fifty years ago. Climate change also refers to the increase in greenhouse gases, among which carbon dioxide figures prominently. However, the effects of CO2 on the overall global climate may be more important than the direct impact on the grape vine. While this subject has not been fully studied, CO2 tends to stimulate the vine's growth and fruit yield, offsetting the effects of higher temperatures. In sum, climate change has had highly variable results according to region and grape variety up to now. Moreover, the outcomes have not automatically been negative; to the contrary, studies (by scientist Gregory V. Jones) have correlated increases in growing season temperatures with higher ratings by wine critics! This may seem odd at first glance. Consider, however, that warmer, drier conditions can translate into riper grapes with more sugar and less acidity. That means richer, softer, more flavorful wines which impress wine reviewers - and many consumers. Of course, if this trend continues, some argue, Pinot Noir may no longer be perfectly suited to what once was a marginal climate (for this variety) in Burgundy, while Syrah could become a better choice. Higher temperatures in Champagne may threaten the region's vivid natural acidity. This sort of development could be revolutionary, forcing a rewriting of appellation laws. But we haven't reached that point, and growers can adapt in many ways to a changing climate. The easiest remedy is to alter winemaking practices, such as making small changes in blending by favoring one grape or lot over another, or resorting to other technical solutions including adding acidity to low-acid juice, diluting overly rich wines with water, or removing alcohol. All of these tactics are already being used around the world where regulations allow more freedom than in many classic European denominations. If conditions change more radically, the grape variety, clones, trellising and rootstocks could be altered, and vineyards could move to higher, cooler elevations where possible. There is no justification, in other words, to predict doom in the world of wine. There will be winners and losers as climate changes: As one region becomes too hot and dry for its current grape varieties, conditions in a nearby, probably more northerly area that has been too cool and wet could become favorable for wine growing. This raises the prospect of exciting new wines in the future!
