When we come to September in many regions of France, one thinks of grape harvest. There is great concern that wine grapes in the Burgundy region of eastern France have been picked 13 days earlier on average since 1988 according to a recent study. Tom Bawden explains in an article on the i news website.
Grape harvest in Burgundy has moved forward by nearly two weeks due to climate change
With its need for hot, dry conditions Burgundy wine grapes are as good a barometer of climate change as any.
And so, as if any more evidence was needed that global warming was already upon us, researchers have found that the grape picking season has moved forward by nearly two weeks in recent decades.
Wine grapes in the Burgundy region of eastern France have been picked 13 days earlier on average since 1988 than they were in the previous six centuries, a study shows.
“We did not anticipate that the accelerated warming trend since the mid-1980s would stand out so clearly,” said Professor Christian Pfister, of the University of Bern in Switzerland.
The changes are marked
“The transition to a rapid global warming period after 1988 stands out very clearly. The exceptional character of the last 30 years becomes apparent to everybody,” he added.
To do the study, the researchers reconstructed dates of grape harvest in Beaune – the wine capital of Burgundy – going back to 1354.
Extract of the expenses provided by the church of Notre-Dame of Beaune for the grape harvesting works in the region in 1385 (Photo: Archives Départementales de la Côte d’Or, 2918/24, Thomas Labbé)
They used a large number of unedited archival sources, including information on wage payments made to grape pickers, Beaune city council records and newspaper reports. The continuous record of grape harvest dates now published in the paper extends until 2018 and is the longest ever reconstructed.
“The record is clearly divided in two parts,” says Thomas Labbé, of the universities of Burgundy and Leipzig, who masterminded the date reconstructions.
Until 1987, wine grapes were typically picked from 28 September onward, while harvests have begun 13 days earlier on average since 1988, on September 15.
The team’s analysis shows very hot and dry years were uncommon in the past, but have become the norm in the last 30 years.
Highly climate sensitive
Grape harvest dates can be used as a proxy to study the climate because wine grapes are very sensitive to temperature and rainfall, the researchers said, citing the French tourism website.
As an article in the French tourism website france.fr puts it, “Mother Nature is really the one who decides” when grapes are ripe enough to be picked. In years when the spring-summer (the growing season) is hot and dry, the grapes are ready for harvest earlier than in colder years, they said.
The study is published in the Climate of the Past journal.