Harvest time in Beaune, a witness to climate change

In 1792, the Republican calendar named the month from 22 September to 21 October as the “vendémiaire” – a reference to the grape harvest. A truly bygone era, as the grape harvest is increasingly being brought forward due to the influence of climate change: rising temperatures are accelerating the ripening of grapes.

In Beaune (Côte-d’Or), the average start date of the harvest is becoming earlier and earlier during the year, according to a study compiling harvest dates since 1354, published in the scientific journal Climate of the past in 2019.

Its main author, Thomas Labbé, co-founder of the historical study group PArHis and associate researcher at the University of Burgundy, provided the information World an updated version to date the Pinot Noir harvest in Beaune, September 13, 2024.

The following graph represents the date of grape variety harvest at the Hospices de Beaune since 1354, with a possible extension to the recent period. Each point represents one year, the red line corresponds to the eleven-year moving average (five years earlier, five years later). This data shows that harvests have been brought forward by about two and a half weeks since the mid-1980s.

The reflection of 670 years of harvest

This database, which dates back 670 years, was reconstructed from multiple archives. “The economic importance of the vineyard means that we have vestiges that go back far into the archives”explains Mr. Labbé.

HE “harvest bans”by which local authorities authorize the start of the harvests, allow us to find very well preserved information, especially in the Middle Ages and under the Ancien Régime, where they represented an important feudal right. For the oldest vintages, in the 14th^my century, the date was established from the accounts of the church of Notre-Dame de Beaune. For other periods, researchers use the records of the deliberations of the chapter of Notre-Dame de Beaune and then the deliberations of the town council, or even, since 1966, articles in the regional press (for the pinot noir of the Domaine des Hospices de Beaune).

The historical depth of the data collected shows some vintages of rare precocity in the 16th century.^my century. But “These “exceptional” years of the past have increasingly become the norm”Mr Labbé comments. Since 1980, only two harvests have been made in October and, of the first fifteen years of the series, eight date back less than twenty-five years.

A wine indicator that has become a climate indicator

This database on the Burgundy grape harvest is, like the cherry blossom dates in Japan, a historical indicator of climate change, cited in the sixth IPCC report.

The advancement of harvest dates has also been noted in other vineyards, in Alsace or Champagne, with less historical significance. Of course, there are margins of error and limits of interpretation in the links between climate and harvest dates. First of all, these are not a “thermometer” : “They remain primarily a viticultural indicator, which has become a climatic indicator because it is closely correlated with temperatures”explains Mr. Labbé.

Other factors, such as changes in viticultural practices and tastes, may also have changed the harvest date. “Depending on the period, we do not seek to make the same wines. We can assume that in older times we sought wines to drink very young, perhaps with more acidity.. On the contrary, during the XX^my century, what we are looking for are high concentrations of sugar”But, according to the historian’s research, rising summer temperatures remain the main factor influencing the timing of the harvest.

Beyond the harvest date, climate change can have repercussions on the quality and flavour of wines: higher alcohol levels, lower acidity, etc. The sector is forced to adapt and consider, for example, changing grape varieties. Some producers also decide to establish themselves in regions further north, where winemaking activity has historically been marginal, such as in Brittany or Normandy.