If life is too short to drink bad wine, then climate change is messing with our options.
Rising temperatures associated with human-caused climate change are pushing grape harvesting in France earlier than growers have experienced in centuries, possibly changing wine quality for years to come, according to a new study in Nature Climate Change. “We don’t need to talk about how climate change will affect wine in the future, we can see that it’s affecting it right now,” said Benjamin Cook, lead author and a climate scientist at Columbia University’s Lamont-Doherty Earth Observatory.
The study published Monday comes as grapes, one of the most valuable cash crops in the world, have been at the forefront of climate change worries. That’s because the caliber of a wine bottle is the sum of complicated environmental factors — what vintners call terroir — at play during grape growth. Terroir and grapes are sensitive, so if rain or temperature patterns change, grapes may grow too slow or not enough, producing undesirable sugar levels that produce low alcohol content. On the other hand, the weather can also induce quicker growth, which tends to improve grapes’ sugar content, increase alcohol levels, and reduce acidity.
For more than 30 years now, wine grape harvest in France has happened on average two weeks earlier than it has in the past 400 years, all without the aid of a drought, according to the study. And while an early harvest is generally associated with higher wine quality, researchers say French viticulture has unprecedented growing conditions that may exert unknown tipping points in the future. “One of the things that we noticed is that before about 1980, to get an early harvest, or to get a summer hot enough to get an early harvest, you needed a drought,” Cook told ThinkProgress. “After 1980, because of climate change, it can get hot enough for an early harvest without a drought.”
CREDIT: AP Photo/Bob Edme
To reach their conclusions, Cook and Harvard biologist Elizabeth Wolkovich analyzed data from the last four centuries. They had wine harvest data from across France, including those from major wine growing regions of Bordeaux and Burgundy. They also had independent sources of climate information, including tree-ring studies and historical documents like trade archives, church documents, and local weather observations. “So what we were able to do is look at climate and wine over a much longer time period than people have typically done and [see] how exceptional the most recent decades are compared to the last 400 years of climate and wine variability,” Cook said.
The most dramatic case of an early wine harvest happened in 2003, following a European heat wave that in France killed more than 15,000 people. Harvest that year happened in August, about a month early, said Cook, adding this was the earliest harvest recorded since the 1600s. “You might expect that with such an early harvest you will really get good wine. But if you look at the wine quality for that particular year, there is nothing really exceptional.”
Jimena Rábago, a viticultural agronomist, doesn’t seem surprised. In a phone interview, she said not all grapes benefit from an early harvest. “For the white [grapes] an early harvest is fine because white grapes don’t need to develop flavors, aromas or colors in the skin,” said Rábago, who works for prestigious vineyards in the ballooning wine industry of Baja California, Mexico. “Red grapes do.”
France could thus experience different benefits and costs depending on the region. In Burgundy, for instance, 61 percent of wine produced is white, while 30 percent is red. But in Bordeaux, the world’s most popular wine region, close to 90 percent of its wine production is red, according to the Wine Cellar Insider.
“The bad news is that if we keep warming the globe we will reach a tipping point,” Wolkovich said in a statement. “The trend, in general, is that earlier harvests lead to higher-quality wine, but you can connect the dots here … we have several data points that tell us there is a threshold we will probably cross in the future where higher temperatures will not produce higher quality.”
CREDIT: AP Photo/Bob Edme
The threshold remains unclear for researchers, but in late 2015 Euromonitor International reported that French wine has been suffering from poor crops already. “Disastrous” climatic conditions caused the grape harvest to be limited in 2013, according to the report, affecting wine volume in 2014, creating low stocks and higher prices. Production has recuperated since then, however.
Still, climate change is a comprehensive problem that extends beyond French borders and needs answers that appropriate local conditions, Rábago explained. “Some areas will have more water, others will have less,” she said, pointing to just one example of a problem climate change brings. In California’s Napa Valley and Baja California, Rábago said, drought seems to the norm while in Bordeaux — on top of higher temperatures — it may be varying humidity. In response, vineyards need to adapt to the current effects of global warming. One way to do so is by changing soil composition so that it holds more — or less — water, or by creating weather resisting grapes. “That implies changing how we plant vineyards,” Rábago said in Spanish, “but also having less of a carbon footprint by moving away from tractor and pesticide use.”
As impacts of global warming have accelerated in recent years, the $200 billion wine industry has responded, though. In Australia, winemakers are moving south to the island of Tasmania, Reuters reported. In Chile, the world’s fourth-largest wine exporter, vineyards are moving to cooler, wetter climates farther south. Others are moving their production uphill or changing the type of vines they grow. In England, for example, some have planted “champagne” vineyards more common in southern, milder climes. But while appropriating new “terroir” may be a new opportunity, a massive move of vineyards could encroach on wildlife. According to a 2013 study published in the Proceedings of the National Academy of Sciences, areas that could become prime for viticulture in the United States or China house endangered animals like bears.
What’s more, climate change may affect wine flavors through factors that have nothing to do with the grapes and vineyards can’t control. Scientists are now reporting a shift in cork trees, the source of wine’s often overlooked companion that regulates the oxygen intake that makes wine evolve over time. In the past two decades, cork bark has become thinner, according to a 2014 study. Researchers said this lower quality cork tree likely stems from a warming weather and increased exposure to ultraviolet light brought on by climate change, which in turn affects tree chemistry.
“Our studies and other studies are really just starting to [show] how climate is really affecting these vineyards and the wine grapes and wine in general,” said Cook. “There’s still a lot we don’t know and a lot of details that we need to start working out.
Bryan Dewan contributed reporting to this article.