"Silent Night" and the volcano. The climate history of a Christmas carol

The online encyclopedia Wikipedia describes "Silent Night, Holy Night" as the "world's most famous Christmas carol". Translated into more than 300 languages, it symbolizes the peace of the Christmas season for many people in all countries. The assistant pastor Joseph Franz Mohr (1792-1848), however, wrote the text of the song in the winter of 1816 in Mariapfarr in the Lungau area in Salzburg against the background of bitter need. Hunger and misery did not only affect the people in the surroundings of Mohr, but also in many regions of Europe and the world.

More than a year earlier, in April 1815, this global crisis had been triggered by the tremendous eruption of the Tambora volcano on the island of Sumbawa in present-day Indonesia. Already in the years before several volcanoes had erupted in the region (so the Awu on the Indonesian island of Sangihe Besar in 1812 or the Mayon on the Philippines in 1814). However, with a magnitude of 7 on the Volcanic Explosivity Index (VEI), the Tambora eruption reached 100 times the power of these earlier events and still ten times of the famous Krakatau eruption of 1883. From the original Tambora height of 4,200 meters, nearly 1,400 meters were blasted away, and about 150 cubic kilometers of volcanic material expelled.

Fig. 1: The location of the volcano Tambora in Indonesia and the ash deposits during the eruption in 1815 (Source: https://de.wikipedia.org/wiki/Tambora#/media/Datei:1815_tambora_explosion_B.png)

First, the disaster hit the inhabitants of Sumbawa, but also on neighboring islands like Bali. Tens of thousands of people died from the direct effects of the eruption or later due to the devastation of their fields by volcanic ashes (which only turned out to be a blessing for agriculture years later). The eruption column of the Tambora reached a height of more than 25 kilometers into the upper layers of the atmosphere. The ejected material spread there in the following months across the entire globe and influenced the shape of the celestial phenomena, but especially the weather.

For several years one could observe unusual colors at sunsets, caused by the volcanic dust particles and immortalized by artists such as the English painter William Turner (1775-1851). However, the climatic consequences of the change in the atmosphere were fatal. 1816 turned into a "year without a summer," when unexpected cold spells and long-running rainstorms were recorded in many regions of North America and Europe, where the Napoleonic Wars had just come to an end and people had hoped for more peaceful times. These extreme events reduced or entirely destroyed the harvests of various crops. The shortages and rises in the prices of food, famine and misery affected large population groups. The states of Europe were - after years of warfare - insufficiently prepared for the catastrophe, although attempts were made to reduce the lack of food by export bans, price regulations and measures against speculators and usurers. However, the state authorities were at least as interested in containing potentially revolutionary riots and acted against the growing numbers of beggars and vagrants.

Fig. 2: Comparison of the summer temperatures of 1816 in Europe to the long-term mean 1971-2000 (source: https://de.wikipedia.org/wiki/Jahr_ohne_Sommer#/media/Datei:1816_summer.png)

These dramatic events also aroused the interest of contemporary authors, such as Johann Wolfgang von Goethe (1749-1832), who as Minister in Weimar had to be officially interested in their effects, although he was especially struck by the death of his wife Christiane in June 1816. The young English writer Mary Shelley (1797-1851) stayed with her family in 1816 in particularly disaster-ridden Switzerland and was inspired by the extraordinary weather events around Lake Geneva for her 1818 published novel "Frankenstein or The Modern Prometheus". However, probably more directly than the famous poet in Weimar or the wealthy Englishwoman the pastor Joseph Franz Mohr became aware of the misery of the people, since in December 1792 he himself had been born in a poorhouse of the Archdiocese of Salzburg.

For Salzburg, which was finally added to the Austrian Empire in 1816, a commission in December of that year stated that "the prices have risen to an unprecedented level in history." The Lungau in the southeast of Salzburg, climatically not particularly favored anyway, suffered from record precipitation and extreme cold, which aggravated in the winter of 1816/1817. In this sad time Joseph Franz Mohr wrote in Mariapfarr the verses of the "Silent Night", which contrasted the misery in simple words with the message of hope of Christmas: "Jesus the Savior is here!", as it says in the last verse in the original text.

Fig. 3: Autograph of the song "Silent Night, Holy Night" by Joseph Franz Mohr, c. 1820 (source: https://de.wikipedia.org/wiki/Stille_Nacht,_heilige_Nacht#/media/Datei:Autograph_Mohr_Stille_Nacht.png)

However, the misery continued in the following year; the record winter of 1816/1817 was followed by an increased number of avalanche declines and floods. After the crop failures of the previous year, grain prices reached their peak in the spring of 1817. And even in the summer of this year, extreme weather events such as thunderstorms with heavy rain caused damage to settlements and fields. In the face of sheer distress, the authorities recorded an increase in crime in many areas in Austria and Germany; hunters in the Alpine regions noted an unprecedented number of acts of poaching.

Meanwhile, Joseph Franz Mohr was transferred in September 1817 from Mariapfarr to Oberndorf on the banks of the river Salzach near the city of Salzburg. There, too, the people who lived on the river, among other things from the salt trade, suffered under the extremes of nature, such as floods and the general decline in trade caused by the crisis. With his superior pastor Georg Heinrich Joseph Nöstler Mohr soon came into conflict. He found a friend, however, in the teacher Franz Xaver Gruber (1787-1863) from the nearby village Arnsdorf, who served in the Church of St. Nikola in Oberndorf as a cantor and organist. Gruber, too, came from the simplest of circumstances and had been born in Unterweitzberg in the Innviertel as the son of a linen weaver. This industry suffered especially from the consequences of rising prices and dwindling sales, but also from the new competition of industrial textile production from England.

Fig. 4: The crater of the volcano Tambora today and the Silent Night Chapel in Oberndorf near Salzburg during the Advent season (source: https://de.wikipedia.org)

At the turn of the year 1817/1818, Europe was in desperate desire for an end of the time of need. But only in the course of the new year, the climatic and economic effects of the Tambora eruption weakened. In 1819 food prices returned to their usual level. During this time between misery and hope Joseph Franz Mohr and Franz Xaver Gruber performed the song "Silent Night, Holy Night" in the Church of St. Nikola in Oberndorf on Christmas Eve 1818, after Gruber had composed a melody to the already two years old verses of his friend.

Mohr and Gruber, as well as their better-informed contemporaries, did not see through the connection between this time of distress and the outbreak of the Tambora, even though news of the huge eruption in Southeast Asia in the years after 1815 spread to Europe as well. Only the ascent of the volcano in 1847 by the Swiss botanist Heinrich Zollinger (1818-1859) and his team allowed more accurate conclusions about the extent of the natural event. The poet of the "Silent Night", Joseph Franz Mohr, died a year later on 4 December 1848 in Wagrain in Pongau, where he had served since 1837 as a parish vicar. At this time, the song had already begun its triumphal procession in the world and was first heard in 1840 in New York. And meanwhile there is also a translation into the Malay language, which is widespread in Indonesia: "Malam Kudus ...".



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Dr. Johannes Preiser-Kapeller is senior researcher at the Institute for Medieval Research / Division of Byzantium Research of the Austrian Academy of Sciences. His research interests include the impact of climatic and ecological changes on societies of the past.