The longest homogeneous series of grape harvest dates, Beaune 1354–2018, and its significance for the understanding of past and present climate

Abstract

Records of grape harvest dates (GHDs) are the oldest and the longest continuous phenological data in Europe. However, many available series, including the wellknown (Dijon) Burgundy series, are error prone because scholars so far have uncritically drawn the data from 19th century publications instead of going back to the archives. The GHDs from the famous vine region of Beaune (Burgundy) were entirely drawn from the archives and critically cross-checked with narrative evidence. In order to reconstruct temperature, the series was calibrated against the long Paris temperature series comprising the 360 years from 1659 to 2018. The 664-year-long Beaune series from 1354 to 2018 is also significantly correlated with tree-ring and documentary proxy evidence as well as with the central European temperature series (from 1500). The series is clearly subdivided into two parts. From 1354 to 1987 grapes were on average picked from 28 September on, whereby during the last 31-year-long period of rapid warming from 1988 to 2018 harvests began 13 d earlier. Early harvest dates are shown to be accompanied by high pressure over western-central Europe and atmospheric blocking over Denmark. The 33 extremely early harvests comprising the fifth percentile bracket of GHDs are unevenly distributed over time; 21 of them occurred between 1393 and 1719, while this is the case for just 5 years between 1720 and 2002. Since the hot summer of 2003, 8 out of 16 spring-summer periods were outstanding according to the statistics of the last 664 years, no less than 5 among them within the last 8 years. In the Paris temperature measurements since 1659, April-to-July temperature reached the highest value ever in 2018. In sum, the 664-year-long Beaune GHD series demonstrates that outstanding hot and dry years in the past were outliers, while they have become the norm since the transition to rapid warming in 1988.

Central Europe, 1531–1540 CE: The driest summer decade of the past five centuries?

“…In Burgundy and Alsace, the grape, fruit and grain harvests were early and good in 1536 (Buisman, 1998). French grape-harvest days at Beaune (Labbé et al, 2019) correlate closely with the general character of the summers of 1531-1540, as well as with that of other central European series (Fig. 16b).…”

Central Europe, 1531–1540 CE: The driest summer decade of the past five centuries?

“…A rainy June with flooding and a cold summer are mentioned in German sources for Mansfeld (Spangenberg, 1572), as well as for Regensburg (Freiherrn von Oefele, 1878) and for Jena (Koch, 1937). Floods were also reported in the north of Germany (Lappenberg, 1861). A good harvest of crops and fruit was observed around Stuttgart (Ginschopff, 1631).…”

“…However, it should also be pointed out that people had no problems with access to water in the towns sit-uated near big rivers such as the River Vistula in Poland, even in times of extreme drought. On the other hand, wet summers were sometimes accompanied by floods that could cause material damage and flooding of agricultural land, or even loss of human lives, as was apparent in 1533 in Bohemia (Zilynskyj, 1984), Poland (including Silesia) (Büsching, 1819;Maurer, 1878), Switzerland (Fouquet, 1999), andTransylvania (Vereins-Ausschuß, 1851;Gross and Seraphin, 1903b) and again in 1537 in Bohemia (Zilynskyj, 1984), Silesia (Büsching, 1819), and Germany (e.g., Spangenberg, 1572;Lappenberg, 1861;Freihern von Oefele, 1878;Koch, 1937).…”

“…Marcin Biem of Olkusz (ca. 1470-1540), astronomer, theologian, and professor and rector of the Kraków Academy, kept daily records for 1531-1540, although from 1532 to 1534 they are incomplete or missing (Limanówka, 2001). For example, after some quite hot and nice days between 28 July and 2 August 1537, he described the weather in the first 10 d of August (ibid.,p.…”

Droughts in Bern and in Rouen from the 14th to the beginning of the 18th century derived from documentary evidence

“…If sources contain series of proxy data which give indirect information on weather-related processes such as plant or ice phenologyfurther statistical analyses are necessary (e.g. Pribyl et al, 2013;Labbé et al, 2019). As the characteristics of the sources are different, it is necessary to consider the potential and the limits of the weather-related information for each source and in some cases even for each record (Camenisch, 2015b).…”