Climate change shifts vintage

Grape harvesting in Burgundy now begins 13 days earlier than was customary for centuries

Harvesting starts earlier and earlier - a consequence of climate change © Esperanza33 / istock
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Premature Grapes: Climate change is already having a noticeable effect on the grape harvest. According to historical data from Burgundy, winemakers have started harvesting an average of 13 days earlier than was customary for centuries before in the last 30 years. This shift is closely linked to climatic changes. Because warmer and drier summers ensure that the grapes mature in the meantime.

Climate change is also affecting agriculture: Rising temperatures and increasing drought are already leading to measurable crop losses in the most important crops. But even with luxury goods such as beer and coffee, the global warming is noticeable. The same applies to wine: winemakers will probably have to rely on other grape varieties and new irrigation methods in the future. In addition, the chronology of viticulture is changing - in many places, the harvest is already starting earlier and earlier.

Over 600 years of wine history

The extent to which climate change has had an impact on the grape harvest in recent years has been investigated by Thomas Labbé of the University of Leipzig and his colleagues using the example of Beaune - the "wine capital" of Burgundy. The researchers researched in old salary payment documents, newspaper articles and city council protocols to find out past harvest dates.

They managed to look back remarkably long into the past: the information gathered by the scientists tells the story of the grape harvest of the last 664 years, from 1354 to 2018. According to them, it is the longest contiguous documentation of grape harvests ever published,

13 days earlier than before

But what do these data reveal? As reported by Labbé's team, the analysis revealed a clear dichotomy: until 1987, grape harvesting in Burgundy typically began on 28 September. But after that there was a clear time shift. Accordingly, the harvest of grapes took place since 1988 on average 13 days earlier. display

Comparisons with temperature records showed that this shift was apparently driven by climatic changes. Thus, very warm and dry spring and summer have been much more common in the last 30 years than before. "We did not expect that the warming trend since the mid-1980s would be so well read from the harvest data, " states co-author Christian Pfister of the University of Bern.

From the exit to the norm

However, it also showed that the most extreme heat and drought years were not always those with the earliest start of reading. If high temperatures cause the grapes to ripen to a certain extent, excessive extremes seem to do the opposite. This becomes clear, for example, in the historical heat years of 1473 and 1540, as the researchers report.

"We expect that the long rainless periods and hot temperatures slowed or even stopped the development of the grapes, " they explain. Hitzesmermer like these were at that time Ausrei er - today they would, however, more and more to the norm. "The extraordinary character of the last 30 years is more than clear from our data, " concludes Pfister. (Climate of the Past, 2019; doi: 10.5194 / cp-15-1-2019)

Source: European Geosciences Union

- Daniel Albat