IN THE FOOTBALLS from Chianti Classico in central Italy, Elena Lapini and her husband walk down rows of neat vines and inspect their fruit. The grapes ripen too quickly under the scorching sun. Too much tan on the vine and they will wither to raisins, turning the wine into a syrupy, unpleasant mixture. For this reason, getting the right harvest date is crucial, explains Ms. Lapini. But climate change is making the task more and more difficult.
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Analysis of harvest dates going back to 1354 in Burgundy, France revealed that air temperatures have risen so much that grapes are now harvested two weeks earlier than in medieval times. Higher peak temperatures have become the norm, with the biggest jump in the past 30 years. Elizabeth Wolkovich, a biologist at the University of British Columbia who studies the impact of climate change on vineyards, says rising temperatures are also changing the taste of the wine itself.
For some cooler regions, warming conditions have allowed wine growers to grow tastier berries and enjoy longer growing seasons. Germany, best known for its white Riesling wines, has become more favorable to the caloric grapes used to make reds like pinot noir. Parts of rain-soaked Britain now have the perfect climate for making sparkling wines, giving British champagnes from Kent and Sussex a fair fight against French champagne. But hotter places like France, Italy and Spain had a rotten deal. Ripening the grapes at a higher temperature means more sugar and less acidity in the berry, resulting in wines that are high in alcohol and similar to honey.
Climate change threatens the world’s wine supply, not just the flavor of the wines. In April, Italian and French growers found themselves lighting thousands of bucket-sized candles to warm the air and ward off a deadly frost that threatened to destroy buds emerging with the first heat waves of spring. It was not enough. In some areas, frost wiped out 90% of the harvest, resulting in an estimated loss of 2 billion euros. The French authorities described it as “probably the biggest agricultural disaster of the beginning of the 21st century”.
Scientists concluded that the plants were caused to bud early by record high temperatures in March. This made the chilly nights in early April particularly damaging. Climate change can make such events more frequent.
Some areas are better dressed for the weather; 51% of shrub areas in Europe are vulnerable, compared to only 7% in North America. Part of the problem is that European species are not well adapted to a warming world. They bud early, reacting quickly to warming air temperature only to die once they drop suddenly. North America, on the other hand, is home to cautious species with coping strategies. They do not bud until they have had a sufficiently long winter, regardless of the short periods of heat in the spring.
Geographical differences help explain why. In the absence of east-west mountain ranges in North America, warm air from the Gulf of Mexico and cold air from arctic regions move freely across the continent, creating large fluctuations in temperature over short periods of time. . Constantin Zohner, biologist at ETH ZÃ¼rich, jokes that the plants don’t want to take any risks in such an unpredictable climate. European winegrowers, he believes, must take note and plant more resistant and diverse grape varieties. There’s no time to lose. â
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This article appeared in the Europe section of the print edition under the headline “The grapes are extinct”