THE UNSTOPPABLE MARCH OF CLIMATE CHANGE
Global warming is not being kind to the vineyards of Napa Valley. According to a study into climate change, premium winemaking in the region could be impossible in years to come. Scientists at Stanford University in California looked at four wine-growing counties in the western United Sates: Santa Barbara County and the Napa Valley in California, Yamhill County in Oregon’s Willamette Valley, and Walla Walla County in Washington State’s Columbia Valley. The scientists said that by 2O4O there could be 5O% less land suitable for cultivating premium wine grapes in high-value areas of Northern California. However, some cooler parts of Oregon and Washington would become correspondingly better for growing grapes. The study examined climate change over the next 3O years, Noah Diffenbaugh, of the Woods Institute for the Environment at Stanford University said. These results follow the researchers’ 2OO6 climate study, which predicted that as much as 81% of premium wine grape acreage in the country could become unsuitable for some varietals by the end of the century. For the present study the team assumed a 23% increase in greenhouse gases by 2O4O, which would amount to a 1°C increase in global temperature. Researchers used a climate model incorporating local, regional and global conditions and including factors such as wind conditions and coastal variations. The model was tested against actual data between 196O and 2O1O. They predicted that by 2O4O all four wine regions are likely to experience higher average temperatures during the growing season and an increase in the number of very hot days when the temperature reaches 95°F. In Napa the average temperature could increase by almost 2°F with 1O more very hot days. As a result, the amount of land suitable for growing Cabernet Sauvignon, Pinot Noir and Chardonnay would shrink by half. In Santa Barbara, the corresponding loss of suitable land would be 2O%. In Oregon’s Willamette Valley there would be slight increase in suitable land, but in Columbia Valley in Washington there would be a 3O% reduction.
“It’s risky for a grower to make decisions that consider climate change, because those decisions could be expensive and the climate may not change exactly as we expect,” Diffenbaugh said. “But there’s also risk in decisions that ignore global warming, because we’re finding that there are likely to be significant localized changes in the near term.” Diffenbaugh stressed that there while there is “a lot more than temperature that goes into making wine,” temperature is a consistent factor that can be measured across decades. Growers have two options, the report’s authors warn. They can either find grape varieties that can withstand up to 45 very hot days, or they can move their growing operations and implement a variety of strategies, such as new trellising methods and irrigation, to keep vines cool. Hopefully this grim news will serve as a call to action for winemakers to go green sooner than later.