The grapes used to make Burgundy wine in eastern France have long been considered a gauge of shifts in climate. Now a new study based on grape harvest dates of several centuries, suggests that the rate of warming has accelerated in the past 30 years, and particularly so in the beginning of this century.

For 658 years, winegrowers in Burgundy tracked when they began harvesting grapes each year. Since the 14th Century, they recorded this information in what are known as "Vendange Annals". Now, researchers took the data from the annals, along with meteorological records going back to 1742 to analyze the effects of climate change on the region's wine industry.

The study, published in the journal Climatic Change, found that grape harvests in Burgundy have been advancing over the past six and half centuries, mirroring an overall increase in local temperatures. But the rise in temperatures and shifts in grape harvesting dates have become more dramatic recently, particularly since the 1980s.

While the average harvest date in Burgundy was Sept. 29 over the entire 658 years, the average date in the past three decades has been a month earlier, Aug. 29, study author Benjamin Bois said in a statement.

"Our study shows that Burgundy's winegrowers are not only sensitive to climate change, they are also excellent observers, which is what is needed to accurately describe the effects of global warming," he added.

Earlier harvesting does not necessarily reduce the quality of the wine. Some experts believe it does quite the opposite. In 2020, the Burgundy wine harvest began Aug. 22 making it the earliest in 600 years. But experts said the wine was of very good quality.

"The 2020 harvest is exceptional. It is perhaps one of the best that we have done for many years with a combination of maturity, balance, freshness, and structure that is rarely found. The reds and whites are remarkable," wine producer Jacques Lardiere told AFP at the time.

Still, researchers are concerned that if Earth's climate keeps warming at the accelerated pace seen in recent years, the ability of winegrowers to adapt to it could be jeopardized, not only in Burgundy, but also in other wine-growing regions around the world.

"Even if winegrowers have found ways to adapt, there might be a limit to adaptation if the warming continues at this pace because many aspects of the process of wine-making are closely related to the climate and soil," Bois said.