1540 European drought

The 1540 drought in Europe was a climatic event in Europe. The affected region extended from western France to Poland and from Tuscany (Central Italy) to northern Germany. The affected countries were England, Belgium, Netherlands, Luxembourg, France, Switzerland, Germany, Poland, Ukraine, western Russia, Austria, Czech Republic, Slovak Republic, Slovenia, Hungary, North and Central Italy, southern Spain. More than 300 contemporary chroniclers from 14 countries recorded the frequency and intensity of rainfall, as well as the numerous consequences of the drought.^[1][2]

Scientific evaluation and discussion

Main article: Historical climatology

Spatial distribution of 1540 documentary data related to the occurrence of drought. Dots: documentary data evidence (chronicler reports, official letters, rogation ceremonies for rain etc.) of drought (red) and abundance of precipitation (blue; in southern Italy the abundance of precipitation was only during spring).

On the basis of historical records Wetter et al. (2014)^[3] derived that during an eleven-month period there was little rain in Europe, possibly qualifying as a megadrought.^[4] These conclusions however were questioned by Büntgen et al. (2015)^[5] on the basis of additional data (tree rings).

Orth et al. (2016)^[6] concluded that in summer 1540 the mean temperature was above the 1966–2015 mean and with a probability of 20% exceeded that of the 2003 summer; however, the study's mean reconstruction suggests that the summer of 2003 was still overall hotter across much of Europe.

The assumption of a megadrought in the year 1540 is primarily supported by more than 300 contemporary chronicles from across Europe, which consistently describe the effects of prolonged drought and heat, such as a significant precipitation deficit, extremely low levels of major rivers, widespread wildfires, the lowering of groundwater levels (resulting in the drying up of wells), as well as severe consequences for agriculture and livestock farming. Particularly reliable sources include the extensive weather diary of Marcin Biem, the rector of the University of Kraków, whose records allow for the statistical reconstruction of precipitation levels in the Kraków region for the year 1540.^[7] Until his death on November 19, 1540, he kept a weather diary that was unique for the time.^[8]

In contrast, a study published in 2015, based on the analysis of growth rings of various European tree species (dendrochronology, also known as tree-ring dating), concluded that the conducted analyses did not provide evidence of an exceptional drought period throughout 1540.^[9] In their reply, the authors of the aforementioned study (Wetter et al.) pointed out that growth rings may sometimes incompletely or belatedly reflect hot and dry extremes, emphasizing the fact that discrepancies between instrumentally determined and dendrochronological data have often occurred in recent times during climatic "outliers" (the "divergence problem").^[10][11]

A publication from 2016 assumes that the average summer temperature in 1540 exceeded the corresponding average values of the 1966 to 2015 time series and, with a 20 percent probability, even surpassed the heatwave of the summer of 2003.^[12] In this context, the existing uncertainties regarding the available data, which hinder reliable temperature reconstructions for short-term anomalies during the last millennium, were also mentioned.

The weather conditions of 1540 present a paradoxical situation since this exceptional year occurred during the Little Ice Age, which lasted approximately from the early 15th to the mid-19th century. However, the question raised by some studies focuses more on whether this singular event could serve as a "blueprint" for future climatic developments in this geographical context.^[7] According to several scientific studies, there has been a clear tendency worldwide towards the formation of warm and dry climates in recent decades.^[13] With further warming, the disappearance of existing climate zones and the establishment of new ones in Central Europe will likely occur,^[14] similar to what happened at least to some extent almost 500 years ago.

Description

German-language chronicle kept by the winegrower Hans Stolz from Guebwiller (France) for 1540: "Anno 1540 January [from 10th Jan to 9th Feb] was rather cold. February was warm and dry until the end. In March it rained for three days. Then ice was found every morning, but days were warm. April was completely without rain or snow, Likewise, May was sunny and dry, June was dry, except that some rain fell in the end [...]. July [10 July to 9th Aug] was terribly hot and dry throughout so that water became scarce and expensive."^[15]

According to the chronicle of winemaker Hans Stoltz of Guebwiller (Gebweiler) today in France, it was largely dry from 10th February until mid-June, following a moderately cold winter. There was some rain at the beginning of March. April and May were sunny and very warm almost all the time, and from the end of June to 4 August it was scorching hot with no rain at all. August and September saw several rainy days, but only a little rain fell. From October to the end of December, the weather was comparable to April with no frost nor snow.^[15]

The Schwedenfass [de] in the Staatlicher Hofkeller Würzburg [de] was created to host the "once-in-a-millennium wine" of 1540

The Swiss historian Christian Pfister described the events of 1540 in a newspaper interview:^[16]

For eleven months, there was practically no rain, temperatures were five to seven degrees [Celsius] [9–13 °F] above the normal values for the 20th century, in many places summer temperatures must have exceeded 40 °C (104 °F). Many forests in Europe went up in flames, choking smoke darkened the sun, not a single thunderstorm was reported in the summer of 1540. Water was already scarce in May, wells and springs dried up, mills stood still, people starved, livestock was slaughtered. Estimates are that in 1540 half a million people died, mostly from dysentery.

Everything began in northern Italy, with a winter that felt like a July. Not a single drop fell from October 1539 to early April 1540. Then the drought advanced north. ... July brought such a frightful ember-like heat that churches made prayers while the Rhine, Elbe and Seine could be waded through without getting one's feet wet. Where there was still water, the warm broth acquired a green colour, and dead fish floated belly-up. Water levels in Lake Constance sank to record low levels, and Lindau actually became connected to the mainland. Soon the surface water had completely evaporated, soils broke up, some dry cracks were so wide that a foot would fit into them. ...

The first grapes were already ripe by 12 August, in Alsace fruit trees bloomed a second time, in Lindau it was actually enough for a second cherry harvest. At Lake Constance and in Bayreuth wine eventually became cheaper than water, and in Limoges winemakers were harvesting roasted grapes, from which they obtained sherry-like wine, which ... made one quickly drunk.^[16][17]

From the city of Münden there is a description of how in the year 1540 the ducal wine from the vineyard at Questenberg [de] was "so excellent" that it was preferred to foreign wine.^[18]

In the Swiss village of Goldiwil [de], "desperate people went over 500 m [1,600 ft] up and down in elevation every day, only to fill a few barrels of water in Lake Thun".^[19]

Temperatures

Long-term annual temperature trends and anomalies in Central Europe from 1500 to 1999. Deviations from the mean 1961-1990 (°C). Standard error prior to 1760 +/- 0.37 °C)

Monthly and seasonal temperatures in terms of differences from the 1961–1990 period in Germany, Switzerland, and the Czech Lands were estimated from temperature indices based on plant phenological observations in conjunction with detailed weather reports.^[20] The following phenological observations taken from the survey of sources^[21] are given in Gregorian style. The cherry trees were in full bloom around 10 April. The cherries ripened at the end of May. The vines finished flowering before 10 June. The first ripe grapes were picked in Zurich a month later, indicating a 4–5 week lead in vegetation. By the beginning of August, the grapes were ripe in many vineyards, but many berries had dried out. This is why many vine growers waited for more abundant rainfall in September before harvesting.^[22] In July temperatures of over 40°C were possibly reached.^[23] At the beginning of September, the cherry trees blossomed for a second time and in October even the vines in Lindau on Lake Constance blossomed again. Ripe cherries were picked a second time around this time. On “Christmas” (4 January 1541), some grown-ups in Basel demonstratively swam across the Rhine which suggests that water temperatures were still bearable due to the almost persistent warmth in autumn and early winter. Estimated annual temperatures were by far the highest between 1501 and 2000.

Precipitation

Four chroniclers in the Swiss Plateau kept records of precipitation events, including, in some cases, the perceived abundance. The Swiss reformer and scientist Heinrich Bullinger summarised that, in Zurich, 'it never rained for a whole day or night between February and the end of September'.^[24]

The number of days with precipitation (≥1 mm) in the Swiss Plateau, as determined from this evidence, is 81% below the 20th-century average. Precipitation amounts estimated using a model in spring, summer and autumn were significantly lower than 20th century minimums. Assuming average conditions in winter, annual precipitation was around a quarter of the 20th century average value. The value for Krakow, 900 km away, is of the same order of magnitude.^[22]

City fires

In the year 1540, there was an unusually high number of city fires, surpassed only during the height of the Thirty Years' War, in a year without major war damages. In Einbeck, the Krummes Wasser, a stream flowing through the city, was likely dried up. On "Annentag" (the day of Saint Anne), July 26th,^[25] a fire broke out, and the entire city was destroyed in the Einbeck city fire, with between 100 and 500 people dying. There are records of 32 additional city fires in German territory for the year 1540. The fires occurred during a time of political and religious conflicts surrounding the Reformation. In many cases, arson was suspected as the cause of the conflagrations, allegedly motivated by anti-Protestant sentiments. Vagabonds and beggars were often scapegoated, leading to a genuine paranoia regarding arsonists. The year 1540 also became known as the "Mordbrenner-Jahr" (year of arsonists).^[26]

See also

• 2022 European drought
• List of town and city fires