Wine lovers are among the few beneficiaries of climate change, with warmer weather producing a series of exceptional vintages in France. But their good cheer could be short-lived, according to a new study.
An unusual combination of warmer weather without drought conditions is leading to earlier harvests – generally associated with better quality vintages.
But if the trend continues too long, the current run of outstanding grape harvests could end, one of the researchers warns.
“At the heart of a good wine is climate,” Harvard's Elizabeth Wolkovich told reporters. “So the grapes are a very good canary in the coal mine.
“You want to harvest when the grapes are perfectly ripe, when they’ve had enough time to accumulate just the right balance between acid and sugar.
“For much of France, there have been times when it’s difficult to get the exact harvest date growers want because the climate wasn’t warm enough that year. But climate change means the grapes are maturing faster.”
The scientists looked at French records of vintages dating back more than 500 years to prove that grapes are being harvested two weeks earlier on average than they were in the past.
“There are two big points in this paper,” Wolkovich said. “The first is that harvest dates are getting much earlier, and all the evidence points to it being linked to climate change.
“Especially since 1980, when we see a major turning point for temperatures in the northern hemisphere, we see harvest dates across France getting earlier and earlier.
“The bad news is that if we keep warming the globe we will reach a tipping point.”
Traditionally, the study found, early grape harvests in France and Switzerland occurred with higher temperatures during spring and summer, but were delayed by wet conditions.
However, since 1980 extreme heat now occurs more frequently without drought conditions.
Using wine quality ratings of vintages from the Bordeaux and Burgundy regions over the past 100 years, the authors also find that the relationship between wine quality and drought has weakened since 1980.
Bill Condie is a science journalist based in Adelaide, Australia.
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