Article
Climate change has caused and continues to raise keen interest in climatic conditions, notably in the Arctic. This does not only concern the most visible impacts of ongoing change today, but also variations in the past, an important source for climate change modelling. In this article, we purport to analyse unpublished sources concerning Greenland in the 18th and early 19th century from the Moravian Archives in Herrnhut (MAH), Germany, to highlight how this material may provide valuable additional data in this respect. The Moravians’ climatic observations have already been the subject of several articles (Lüdecke, Reference Lüdecke2005; Demarée & Ogilvie, Reference Demaree and Ogilvie2008 and Reference Demarée and Ogilvie2011, Demarée, Ogilvie and Csonka, Reference Demarée, Ogilvie and Csonka2010, Demarée, Ogilvie and Mailier, Reference Demarée, Ogilvie and Mailier2020, Demarée and Ogilvie, Reference Demarée, Ogilvie, Jensz and Petterson2021). However, prior work has focused to a large extent on Labrador in the 19th century and, most recently, on earthquakes in Greenland and Labrador in the 18th and 19th century (Demarée et al., Reference Demarée, Ogilvie and Kusman2019). These articles draw mostly on printed sources. As we are going to show, the study of the Moravians’ unpublished diaries (in old German handwriting) from their missionary stations provides plenty of additional information that can help us to fill in numerous gaps in the 18th and early 19th century before regular observations were introduced in Greenland. The following unpublished German-language sources were consulted by the authors for this article: manuscripts on the history of the meteorological observations of the Unity of Brethren, the founding of an observatory and the natural history collections (“Naturalienkabinett”) in Barby (written by Paul Günther R.6.D.I.b.12 and R.4.E.22); manuscripts relating to Brasen’s travel to Greenland: accounts of the Moravian missions’ agent in Copenhagen (R.19.E.14.a.) and Brasen’s observations concerning the weather, birds, stones and plants as well as collections of specimen and plants (R.15.J.a.13.9, R.15.J.a.22.b); the only letter sent by Brasen to Watteville from Greenland (R.15.J.b.I.24.a.); a manuscript about Cranz’ observations of the weather and the publication of Brasen’s effort in Cranz’ book Fortsetzung der Historie von Grönland… (1770; R.15.J.a.22.b, MDF 1807); observations of the weather presented in a chart with handwritten explanations from Labrador in the 18th century (R.15.K.a.8, MD 1817); a letter about the collecting of specimen in Greenland (R.15.J.b.II.44); a letter on the publication of information about Greenland’s nature and inhabitants in Büsching’s Description of the Earth (R.12.A.a.3.5.b.) and scientifical journals (R.21.A.9.15.); Neu-Herrnhut Diarium (R.15.J.b.I.3.c): December–February 1789–1790 (8 manuscript pages), 1801 (38 manuscript pages), as well as several other entries from the diaries of Neu-Herrnhut and Lichtenau.
Prior to our discussion of the sources, we need to initially get a more precise view of the circumstances in which these observations were made and how the data were produced. We then move on to communication and the media through which some of the observations were made available at the time, before analysing a set of data from manuscript sources that has not been previously discussed. Their interest from a climatological perspective is then assessed in our final section. However, before we reach this stage, let us return to the history of the study of the climate.
The Moravians’ Greenland mission and natural history
Interest in climatic processes can be traced back to Antiquity and Tacitus in particular (Tacitus, AD 98 [Reference Tacitus1999] & AD 98 [Reference Tacitus2010]). Today, climatology, especially historical climatology, (Wigley et al., Reference Wigley1981, Brázdil, Reference Brázdil2000, Pfister, Reference Pfister2001, Jones et al., Reference Jones2013) draws on data in written sources such as chronicles, almanacs and calendars, letters, diaries, travelogues, official documents and the like. As far as the Middle Ages are concerned, accounts of natural disaster and anomalies of road and travel conditions have served as indicators of climatic conditions in central Europe (Pfister, Reference Pfister2001, 7). With the rise of almanacs in the 15th century, individual observations, partly resulting from experimental methods, were printed in astronomic calendars, which have been analysed by historians of the climate (Herbst, Reference Herbst2012). Renaissance and later exploration of the globe produced new knowledge about the world we live in and its climate. Information about the weather in the Arctic was initially written down in logbooks and diaries of whalers who were particularly interested in conditions out at sea, as well as field notes and travelogues of explorers and scholars. The development of whaling rendered more and more descriptions available concerning climatic parameters in the Far North. Early accounts of Greenland and navigation along its Western Shores can be found in John Davis’ writings, notably in his 1595 treatise “The Worldes Hydrographical Discription” (Davis, Reference Hastings Markham1880, 206–208). In his 1647 description of Greenland, written like a chronique scandaleuse, the Huguenot Isaac La Peyrère (1596–1676) focuses on anomalies and the “marvels” – a well-known trope in travelogues – of the Greenlandic climate (La Peyrère, 1647, Germ. 1674). In 1667, the Royal Society published a list of 20 questions concerning Greenland in its Philosophical Transactions, addressed in particular “to some of those English masters of ship and other fit persons that shall suit into Greenland for the whale fishing,” several of these “inquiries” concerning the weather, such as, for example, no. 3: “What weather is most usual at such and such times of the year?” (Anonymous 1667, 554) A very early response can be found in Friderich Martens’ travelogue (Martens Reference Martens1675), published in English as Voyage into Spitzbergen and Greenland in 1694 (Martens Reference Martens1694). Martens recorded climatic conditions on a regular basis during his voyage, providing a chart entitled in the English edition “A Table of the Wind and Weather in the Voyage to SPITZBERGEN” for the period 15 April–21 August 1671, from latitude 56° to 77° (Martens, Reference Martens1694). His observations represent the first effort to produce meteorological data about Svalbard in a systematic way. The German barber Friderich Martens (1635–1699) was to return from his later voyage to Greenland in 1675 with additional information concerning the cold, wind force and direction, sunshine and rain, etc. (Martens, Reference Martens1675). The Royal Society acknowledged his achievements in Philosophical Transactions. In a short piece dedicated to the 1694 collective volume containing Narborough’s accounts as well as those by Abel Jonszoon Tasman (1603–1659), John Wood and Martens, the anonymous author remarks that
Frederick Marten of Hamburgh, undertook his Northern Voyage to satisfy the Commendable Curiosity of the Royal Society, which he has done with admirable Diligence; giving many Specimens of the Fertility of his Genius in making such considerable Observations in the barren and horrid Climate of Greenland, as to the Weather, the Whale-Fishing, the Animals, plants, and other parts of Natural History; as also upon the Physical Phænomena of Snow, Ice &. (Anonymous, 1694, 128).
In the early 18th century, the Dutch seafarer Cornelis Gijsbertsz Zorgdragen (b. 1660) stresses the importance of remarks concerning the weather for navigators and fishermen in his description of Greenland fisheries, observing that particular climatic conditions are the cause of various natural phenomena in Greenland, such as the transformation of icebergs for example (Zorgdrager, Reference Zorgdrager1720, Germ. ed. 1723). Such data were collected during voyages to the North and Greenland in view of more efficient, that-is-to-say safer navigation conditions. May it be observed in passing that descriptions of rough weather from this period contribute also to the rhetoric of the extreme in order to enhance the heroic vanquishing of the natural obstacles, protagonists had to face. More importantly in the present context though, the collecting of exact climate-related data was to become more and more systematic, contributing to the vast and increasingly encyclopaedic effort of the Enlightenment to explore and understand nature through observation, collecting, measuring and classifying as well as the communication of new knowledge among scholars. Observing and classifying meteorological data in particular was part of the ambition to comprehend humans in their environment.
As far as the Arctic is concerned, remarks about the weather and the climate in the first half of the 18th century can still be found in whaling journals. Hamburg mayor Johann Anderson (1674–1773) compiled a number of them together with other sources in his Reference Anderson1746 volume Nachrichten von Island, Grönland und der Strasse Davis (News from Iceland, Greenland and Davis Strait), relating conditions of life of the Danish missionaries and merchants in Greenland directly to the climate. Such observations notwithstanding, the principal contribution to new knowledge about climatic conditions in the Arctic was made by newcomers in this part of the world – the missionaries of the Moravian Brotherhood, from Herrnhut in Saxony, who founded their first mission in Greenland in 1733. The first German-speaking missionaries of the Brotherhood settled close to the Danish station in Godthåb (founded in 1721, now Greenland’s capital Nuuk). They called their station Neu-Herrnhut. In 1758, they founded the second station – Lichtenfels (Akunnat) – and in 1774 the third – Lichtenau (Alluitsoq) (Israel, Reference Israel1969; Olsthoorn, Reference Olsthoorn2013), with several others to follow, some of them only for a number of years, before the Moravians handed over their stations to the Danish Lutheran Church in 1900. The establishment of the first Moravian station to do missionary work among the Greenlanders had become possible for several related reasons. First of all, Count Nikolaus Ludwig von Zinzendorf (1700–1760), founder of the renewed Moravian Brotherhood in the 1720s, who welcomed Protestant exiles from Moravia on his estate Berthelsdorf (near Herrnhut) in Saxony, had been authorised by the Danish King Christian VI. (1699–1746) to send Moravian missionaries to the Danish colonies. Zinzendorf’s demand had received support from his cousin, Sophie Magdalene von Brandenburg-Kulmbach (1700–1770), wife of Christian VI., and a number of courtiers. He tried to obtain the post of Leader of Missions in Greenland and also in Norwegian Lapland. He also proposed to the Danish King to found a university in Flensburg to train missionaries, an idea rejected by the monarch (Bøytler, Reference Bøytler and Mayer2000). Nothing ever came of these ideas but the difficulties the Danish Mission in Godthåb had to go through under the leadership of the Danish-Norwegian Reverend Hans Egede (1686–1758) were favourable to Zinzendorf’s endeavour. The political and religious situation in Saxony was another driving force in this process since attacks from hostile Pietists in Halle (Saxony), among others, forced the Moravian exiles to seek refuge and settle elsewhere in the world.
Moravian activities were organised according to their theological and missiological ideas determining everyday life, work and conversion of Moravian congregations worldwide (Zinzendorf, Reference Zinzendorf and Bintz1979). Relations with Indigenous peoples and missionary methods were important aspects of Zinzendorf’s first general instructions to missionaries in 1738 which did not mention any activities of collecting specimen or observing and describing nature, including the weather (Zinzendorf, Reference Zinzendorf and Bintz1979, 50–55). Nevertheless, Moravian interest in the culture of the Indigenous societies of the Far North and the region’s natural history is witnessed right from the start by a number of objects that were sent back to Germany from Lapland (1735 and 1739), Greenland (1740) and Labrador (1765) (Augustin, Reference Augustin2005, 2). They had been collected to serve as material for the natural history lessons organised at the Moravian Theological Seminar in Barby (Saxony), enhanced by the establishment of a meteorological Observatory and the natural history collections in the years 1756–1758 (see Paul Günther, “Nachricht von denen Gewittern d.15t Jun. 1787, nebst einer Beschreibung des Ganges des Wetterstrahls durch das gebäude des astronomischen Observatorii von einem dieser Gewitter, abends 10h 30’ nebst einer Zeichnung dazu,” manuscript in the MAH, R.6.D.I.b.12; Paul Günther, “An die Unitäts Ältesten Conferenz der Evangel.[ischen] Brüder-Unität Ergebenstes pro Memoria,” manuscript in MAH, R.4.E.22). The Moravians’ collecting of natural specimens and objects as well as the recording of meteorological data was only to become systematic, however, after Zinzendorf’s death in 1760.
The first public recognition of this effort is to be found in the publication of the History of Greenland by Moravian David Cranz (German ed. 1765, Engl. ed., spelling the author’s name Crantz, Reference Crantz1767) who had been commissioned by Zinzendorf in 1759 to write a history of the Greenlandic mission to highlight notably, and legitimise, the Moravian contribution to the systematic observation of natural history phenomena (Demarée, Ogilvie and Mailier, Reference Demarée, Ogilvie and Mailier2020, Demarée and Ogilvie, Reference Demarée, Ogilvie, Jensz and Petterson2021, Kodzik, Reference Kodzik, Jensz and Petterson2021). Cranz regularly observed the weather during his stay in Greenland from August 1761 to July 1762, including data on a monthly basis in his work which first describes Greenland’s natural history before documenting the history of the Brethren’s mission there (Cranz, Reference Cranz1765, 66–69; Engl. 1767,vol. I., 50–52). His observations include parameters such as the direction and force of wind, rainfall, sunshine, thickness of ice, etc. As he did not have a thermometer, he tried to indicate air temperature through approximation. In September, he thus notes
[…] in the beginning north-east wind and warm sun-shine, at the same time ice a finger thick where the sunbeams were excluded. Afterwards south-wind with uncommon warm and settled weather. Then ensued a stormy southwest wind with much rain, and at last a hard storm from the south and then from the north. Now the earth and windows froze without thawing in the sun-shine, the ice in the fresh-water two or three inches thick. (Crantz, Reference Crantz1767, 50)
For November, he observes
[…] in the beginning, uncommon northeast cold, so that strong drink froze out of the warm room, and water in it. The remote bays drove full of flakes of ice, which froze together with the seawater. At the same time the sun shone so warm by day, that what snow had fallen before, was quite evaporated. (Crantz, Reference Crantz1767, 51)
Meteorological conditions impacted the Moravians’ farming activities. Cranz indicates for instance that the best moment to sow seeds is June. He tried to systematise his descriptions by including seasonal and regional observations as well as phenomena seen repeatedly out at sea, in the fjords and on land as well as their connection. Other parameters include for instance strong southerly winds “in the hardest winters” which “usher in a mild air and rain,” (Crantz, Reference Crantz1767, 52). Related data are then compared by Cranz to remarks about Lapland and Spitsbergen (not indicating any source for these latter observations, however).
The considerable interest raised by Cranz’ groundbreaking work in Europe and many queries sent by scholars to the Moravians, concerning, for example, the reaction of corpses to cold (Cranz, Reference Cranz1770, 272–276), led to the decision of the United Brethren in 1766 to send the Moravian physician and botanist Christoph Brasen (1738–1774) for a whole year to Greenland from August 1767 (N.B.: he is usually referred to as Christoph Brasen but there is a letter by him signed Brasens in the Moravian Archives, see his letter from Greenland sent to Watteville, R.15.J.b.I.24.a.). Brasen had bought the medicaments for his voyage to Greenland in June 1766 (see the accounts of the Moravian missions’ agent in Copenhagen and the accounts of the society, manuscript in MAH, R.19.E.14.a). The purpose of his stay was to observe Greenland’s natural history in an even more systematic way and to complement Cranz’ meteorological data while examining the missionaries’ state of health. Brasen was equipped with a thermometer and barometer, receiving instructions how to classify his meteorological observations from the physician and natural historian Christian Gottlieb Kratzenstein (1723–1795), Rector of the University of Copenhagen (see Brasens’ remarks about the weather diary, manuscript in MAH, R.15.J.a.13.9). He was expected to systematically observe the flora and fauna as well as minerals and climate of Greenland. Von Kratzenstein’s system determined the precise moment of observation, indications how to classify the direction and force of wind, as well as rainfall and the composition of the sky. In his first letter, written just after he had arrived in Greenland, Brasen justified his shortcomings as far as the expected observations are concerned by referring to difficult conditions of travel which had made him arrive late: “On April 22, we set sail from Copenhag.[en] but were held back in Helsinør because of contrary winds until May 2.” (Christoph Brasens to Johannes de Watteville, 24 August 1767, Neu-Herrnhut, manuscript in MAH, R.15.J.b.I.24.a) David Cranz regretted the absence of observations for the months preceding August 1767 in his continuation (Fortsetzung) of the history of Greenland (Cranz, Reference Cranz1770, 253). Nonetheless, Brasen did pioneering work as far as Moravian stations worldwide and the mission in Greenland are concerned. He was able to make systematic meteorological observations from 1 August 1767, until 22 July 1768, as well as describing six new bird species briefly, compiling a list of minerals in Greenland with short descriptions and plants classified according to Linnæus’ system (Christoph Brasens, “Vögel aus Grönland; Mineralien von Grönland; Pagina e Linn. Speciebus Plantarum; Observationes in Grönlandt 1767,” manuscript in MAH, R.15.J.a.13.9). He also sent objects and parts of animals to the natural history collections in Barby including minerals, parts from whales, ribs, teeth, reindeer antlers, heads of minnows and seals, mussels and an ivory tobacco box (a list drawn up by Christoph Brasens, s.d., manuscript in MAH, R.15.J.a.13.9).
Meteorological parameters were observed on a daily basis during the months that Cranz had also described in 1761/62. Brasen’s reports and his weather diary were sent to Cranz (David Cranz to Hans Christian von Schweinitz, 2 April 1769, manuscript in MAH, R.15.J.a.22.b; Cranz confirms having received the travel diary of Matthäus Stach from his journey to the South, Brasen’s reports, the diaries of the stations for the years 1767 and 1768, as well as Jens Haven’s travel diary from Labrador) and discussed by the latter in the supplement – Fortsetzung – of his Historie von Grönland (1770), the author appreciating Brasen’s contribution as follows: “these observations are far superior to mine in offering a full grasp of the region’s climate.” (Cranz, Reference Cranz1770, 254) Cranz published tables with selected data for each month concerning extreme weather events taken from Brasen’s report. Comparable data for each month are provided by way of short descriptions. Cranz drew on this knowledge in his general remarks about climatic variations on continents and islands, especially in relation to cold. In doing so, he was also able to confirm a number of observations made by Hans Egede concerning the weather in Greenland (Cranz, Reference Cranz1770, 269–270). Brasen’s results served Cranz to prove his hypothesis that mild winters occurred in turn in Greenland and Germany, comparing meteorological observations of the Moravian missionaries from the years 1756 to 1768 – written down as short remarks about a number of climatic parameters in the diaries of the Moravians’ Greenlandic stations – with observations about the weather and air temperatures in Berlin during the winter months (December, January and February). He also compared Greenlandic data with observations about the weather by Moravian missionary Jens Haven (1724–1796) during the latter’s first voyage to Labrador in 1764 (See David Cranz, “Anmerkungen über die Vorschläge in Labrador,” manuscript in MAH, MDF 1807). Brasen’s weather diary from Greenland was published by von Kratzenstein the same year as Cranz’ Fortsetzung (1770), accompanied by comments in Danish (Kratzenstein, Reference Kratzenstein1770). Brasen’s achievements led the Moravians to send him to Labrador in order to conduct observations of climatic parameters from October 1771 to December 1773 (see “Labradorische Witterungs Observationen von dem 1 November 1772 bis den 29ten Sept. 1773,” manuscript in MAH, R.15.K.a.8; “Wetterbeobachtungen aus Labrador 1771–1781,” manuscript in MAH, MD 1817) – using the same system as he had done in Greenland – and laying the foundations for regular observation of the weather in Labrador (Demarée and Ogilvie, Reference Demaree and Ogilvie2008).
His reports about Greenland’s environment and weather, as well as the natural history specimen he had sent back, notably herbs and other specimen sent to the zoologist Johann Christian Fabricius (1745–1808; see the notes in MAH, R.15.J.a.22.b) and the supplementary remarks added by Cranz in his Fortsetzung der Historie von Grönland, stirred great interest among Moravians and scholars at large, who repeatedly sent queries to the Moravians about the Greenlandic weather, fauna and flora as well as minerals, but also the Greenlanders and their environment. Scholars such as Fabricius from Copenhagen (see Johann Christian Fabricius to the Moravian missionaries in Greenland, 22 May 1769, Copenhagen, manuscript in MAH, R.15.J.a.22.b), physician Georg August Langguth (1711–1782) from Wittenberg or naturalist Johann Hermann (1738–1800) from Strasburg ordered natural history specimen, especially herbs and seal skins (see Johann Jakob Bossart to the Moravian missionaries in Greenland, 31 May 1785, Barby, in J. J. Bossart: Kurze Anweisung Naturalien zu samlen, Braby, with the notice “Friedrichsthal. Lit. G. No. 4c” in MAH). Anton Friedrich Büsching (1724–1793), author of a famous description of the Earth (Büsching, Reference Büsching1770), sent for information about the geography of Greenland, and the customs of the Greenlanders, which he then included in his monumental work (Anton Friedrich Büsching to Johannes Loretz and Paul Eugen Layritz, 16 April 1765, St. Petersburg, manuscript in MAH, R.12.A.a.3.5.b). The Moravian Missions Deputation in Herrnhut encouraged the missionaries in Greenland to collect and sell natural history specimen to finance some of their operations: “perhaps the selling of specimen could pay for the building of the provision house.” (Moravian Missions’ Directorate to Johann Beck and the Moravians in Lichtenfels, 24 January 1770, Herrnhut, manuscript in UAH, R.15.J.b.II.44) Johann Jacob Bossart (1721–1789), Director of the Moravians’ natural history collections in Barby, later wrote brief instructions how to collect natural history specimen (Kurze Anweisung Naturalien zu sammeln), published in 1774, basing himself on Linnæus’ system of classification (Bossart, Reference Bossart and Norfleet1774, Engl. 2013; Augustin, Reference Augustin1994; Jensz, Reference Jensz2017).
The Moravians’ meteorological observations also met with keen interest. Data from Greenland published by Cranz and von Kratzenstein led to several queries. Climate-related data from Labrador, as well as explanations about other natural phenomena from the Far North, notably drew the attention of Rector Johann Daniel Titius (1729–1796) in Wittenberg who published them in the review Wittenbergischen Wochenblatt that he was the editor of. Titius praised the Moravians’ contribution to the development of science in a letter to Bossart in the following terms:
Who would have thought in the early days of your congregation that the diligence of your brethren would contribute to the progress of natural history, geography and knowledge about man as well as science? The remarks of these men are the more valuable, whenever they simply describe conditions, rather than speculating about them. (Johann Daniel Titius to Johann Jakob Bossart, 12 May 1789, Wittenberg, Manuscript in MAH, R.21.A.9.15)
Further attempts to observe the weather in Greenland were undertaken by Societas Meteorologica Palatina, the Meteorological Society of the Palatinate, founded in Mannheim in 1780, which encouraged systematic observations in different parts of the world, publishing results in their yearbook Ephemerides Societatis Meteorologicae Palatinae. As the Society did not manage to persuade the Moravians to conduct such observations at their stations in Greenland, it turned to the Danish missionaries in Godthåb thanks to the mediation of Danish astronomer Thomas Bugges (1740–1815). Danish Reverend Andreas Ginges (1754–1812) was able to make observations in Godthåb from 1782, the year he arrived there, until 1792, with instruments provided by the Society ([Andreas Christian Ginge] Astronomiske og meteorologiske Iagttagelser, anstillede i Godthaab i Grønland 1782–1792, manuscript in Det Kgl. Bibliotek in Copenhagen). Data for the period October 1786–June 1787 were published in the Society’s yearbook in 1787, presented in tables for each month with additional comments (Ginge, Reference Ginge1789).
Though the Moravians did not accept the Society’s proposal, they did participate in some of the observations sporadically. Some climate-related entries from the diaries of their Greenlandic stations in the years 1789–1800, including air temperatures now and then, were published as a supplement to Cranz’ reflections on Greenland’s climate in Gilbert’s Annalen der Physik in 1802 and once more in 1805 in Magazin für den neuesten Zustand der Naturkunde (Magazin, 1805). Various other scholars referred to Moravian observations in their publications. Basing himself on remarks by Egede and Cranz, the philosopher and anthropologist Christoph Meiners (1747–1810) from Göttingen noted in his reflections on the impact of the climate, that the cold climate of Greenland seems to have had a positive effect on the health of the Moravian missionaries there since none of them died from any of the usual fatal diseases in Germany (Meiners, Reference Meiners1789, 24–26). Immanuel Kant concluded from their representations of the Greenlandic climate that the human body was capable of adapting to climatic conditions in order to survive (Kant 1775 [Reference Kant, Rosenkranz and Schubert1839]). Echoing Cranz’ views, he deduced human powers of imagination from the impact of the climate. This idea has been discussed by Johann Gottfried Herder who draws on the theory of the climate to stress the influence of nature and the weather – especially cold – on bodies and the ideas that humans have developed in cold regions, especially in the Arctic (Herder, 1784–1791 [Reference Herder2002], 189).
Data to be found in printed sources
Be that as it may, the Moravian contribution to meteorological and climatic knowledge in the 18th century remains only partially known until the present day. In this part, we wish to present some results of our own exploration of largely unpublished source material, initially conducted within the French research project “Green Greenland,” one of the most notable outcomes of which is the collective volume Le Groenland : Climat, écologie, société, edited by Valérie Masson-Delmottte, Émilie Gauthier, David Grémillet, Jean-Michel Huctin and Diedier Swingedouw, published by CNRS Éditions in 2016. Before doing so, however, we should first get a clearer view of what there is in the way of printed sources.
The earliest printed excerpts from the Moravian diaries one is likely to come across were published by jurist and author Johann Jacob Moser (1701–1785) in his periodical Altes und Neues aus dem Reich Gottes und der übrigen guten und bösen Geister. The second volume (1734) contains the description of the sea voyage of the first three Moravian missionaries sent to Greenland, Matthäus Stach (1711–1787), Christian David (1690–1751) and Christian Stach (Stach, Reference Stach and Verlag1734). Sailing up Greenland’s south-west coast at some distance in May 1733, the latter observes on the 6th
two pieces of ice big like barrels, we continued to sail for a few hours, until we met with so much ice that the ship could hardly move […] and there was such thick fog that one could not see further than 55 steps […]. (ibid., 6)
On the 7th, they went through a storm which lasted for 24 h (ibid., 7). On the 11th, they were making good progress, meeting with icebergs
as large as the tavern in Herrnhut in height and depth, and the biggest part of it is in the water which one cannot see; at first we thought they were big ships as we spotted them at some 3 miles distance. (ibid., 8)
On the 13th, the ship is less than a mile from the coast: “it did not look green, however, but white, though we were on the 13th, there had been snowfall for three days.” (Id.) As we can see from these excerpts, quite a few indirect details allow us to draw conclusions as to some climatic parameters in a particular location at a given time, including wind, the state of the ice (ice floes, icebergs, etc.), rain and snowfall, sunshine, etc. The same volume then contains the account of the first 6 weeks the missionaries spent in Greenland, mainly occupied with the construction of their first house, indicating rain on 5 July, and heavy rainfall on 6 July, preventing them from going outside (Stach, David & Stach Reference Stach and Verlag1734, 30). There is no point in going into further detail about available information here. Excerpts from the station’s diary of the early 1740s were included in a three-volume anthology of writings by, to and about the Moravians, known as “Büdingische Sammlungen,” published in the years 1742–1744, destined to justify their activities in response to virulent attacks from their enemies. Volume II contains a long excerpt (43 pages) of entries from the diary of Neu-Herrnhut for the period 29 July 1740, until 14 July 1741, written by the missionary Johann Beck (1706–1777) (BS, II, 433–476); volume III presents entries for the period 3 August 1742, until 21 July 1743, by Matthäus Stach (56 pages) (BS, III, 346–402). References to the weather are rare in the second volume. The entry for 11 November 1740 informs us that the missionaries returned from an 11-day stay in Kangerme (Kangeq), one of the outposts of the Greenlanders, some 3 miles away from the station, during stormy weather (443). On 10 January 1741, they return from a similar trip during fair weather (450). On the 18th, a “mighty storm” tears apart the windows (454). Stormy weather continues on the 23rd, but fair weather on the following day allows the missionaries to return to their station (455-6). That’s about it. The excerpts from the third volume also contain only little information about the weather: 25 November 1742, an exceptionally strong storm that made the missionaries’ house move (356) and several references to unusually severe cold during the winter (12 February and 1 April 1743 entries notably).
Nothing much in the way of systematic data is therefore to be found in these early printed sources. Once David Cranz has spent a whole year in Greenland and starts publishing his results, followed by Brasen’s observations that Cranz draws on in his Fortsetzung, the situation changes. As mentioned above, samples of Moravian data from Greenland appeared in various scholarly publications, von Kratzenstein editing material the year Cranz’ Fortsetzung was published (1770). The Meteorological Society of the Palatinate’s journal Epheremides reproduced data from Ginges in its volume Observationes Anni 1787 (published in 1789). Scholars might want to compare Ginges’ observations with entries we find in the Neu-Herrnhut diarium for the same period, the latter providing of course indirect information which may serve to confirm Ginges’ data, as they do, for instance, as far as the sea level in early January 1787 is concerned, Ginges noting on the 6th: “Mane fluxus maris solito altior est” (60), with a wind blowing from South-East/South force 4, the Moravians observing on the 4th that “the tide is so strong because of the storm blowing from South that the sea-level is exceptionally high.” (Neu-Herrnhut Diarium, manuscript in MAH, R.15.J.b.I.3.c, entry for 4 January 1787 – our translation, like all excerpts from the Moravian diaries unless otherwise stated). The stormy weather returned on the 6th, hence Ginges’ remark cited above. But the Moravian entries also complement Ginges’ information since he does not offer remarks for every single day (though he does provide data in the tables on a daily basis), nor do the Moravians, but for certain days we may find an entry in their diary and nothing in his remarks. Comparisons between his tables and the Moravian diary may also reveal differences. For example, Ginges’ data for 7 March indicate wind force 2, whereas the Moravians’ note: “The stormy weather has been continuing for quite a long time already” (ibid., entry for 7 March 1787) – the latter indication presumably not matching wind force 2 though both stations, within relatively close walking distance, are unlikely to have experienced significantly different conditions on the same day. Be that as it may, we can manifestly obtain an even fuller picture for the period of observation discussed here, by drawing also on the unpublished Moravian sources.
The meteorological observations published in Annalen der Physik in 1803 are summarising exceptional phenomena from the Moravians’ stations in Greenland and Labrador in the years 1790–1801, to document the relative frequency of these in the period under consideration. For example, remarks from the Moravians’ second station in Greenland, Lichtenfels, some 130 km south of Neu-Herrnhut, for January 1790 are summed up in the following way:
On January 21, 1790, the thermometer rose in Lichtenfels, Greenland, after a period of severe cold, (on December 19, 1789, temperatures had dropped to 18° below freezing point), 5° above freezing. But after a few days, the cold returned again (Annalen, 1803, 207).
It is to be noted that the Moravians indicate temperatures in Réaumur, here −18°R = −22.5°C; +5°R = +6.25°C. Brief information about exceptional data from Greenland and Labrador is then compared year by year, the second part of the article being dedicated to additional information from North America. Virtually identical observations for the same period and locations were reprinted in volume 9 of Magazin für den neuesten Zustand der Naturkunde in 1805 (456–470).
Finally, excerpts from the diaries and correspondence of the missionaries in Greenland and Labrador were also published regularly in the Moravians’ journals, the handwritten Gemeinnachrichten (Mettele, 2009 and Reference Mettele, Friedrich and Schunka2017, 150) and later the printed Nachrichten aus der Brüdergemeine, as well as Periodical Accounts, though not principally to the edification of scholars, but the Moravian congregations worldwide and potential donors. Concerning the German-language journals, Gisela Mettele points out that the Moravians kept a central diary from 1747, known as Gemeinhausdiarium or Jüngerhausdiarium, and Gemeinnachrichten from 1764. “Initially, this central diary circulated in handwritten copies,” she observes, adding: “while form 1818 on, it was printed under the title Nachrichten aus der Brüdergemeine. The second part, intended only for members, was hand-copied up to the middle of the nineteenth century.” (Mettele Reference Mettele, Friedrich and Schunka2017, 150). A number of passages chosen by the journals’ editors do contain remarks about the weather, especially the cold, notably in view of enhancing the missionaries’ stamina, held in admiration not only by other Moravians but many Protestant congregations and individuals at large. Here is a summary of conditions at the third Moravian station in Greenland, Lichtenau (more than 500 km south of Neu-Herrnhut), during winter 1792, summed up by the journal’s editors: “The winter of 1792 had been uncommonly severe, with more snow than has been seen at Lichtenau for these 23 years,” the remarks concerning Neu-Herrnhut for the same period mentioning “intense cold,” (Periodical Accounts, 1790, 201) observations we will return to below in more detail. In the same volume, we also find some indications about extreme weather events in the 1790s:
The Greenlanders had a good year in externals. The last winter, which was so uncommonly severe in Europe, was very mild in Greenland. January 1st, 1795, there was a storm from the S.W. in violence little short of a hurricane. In New Herrnhuth the Greenlanders’ provision house was blown down, and the Missionaries’ house had nearly shared the same fate. In June and July there were such violent storms of thunder and lightning, as the oldest inhabitant had never witnessed. (ibid., 349)
Data from diaries extant only in manuscript form
Let us now turn to the Moravian diaries in more detail to first of all observe that they were principally supposed to record remarkable events. This can be deduced from an entry in the Neu-Herrnhut diarium summing up 21–23 May 1795: “nothing in particular happened other than most brethren and sisters leaving the station with only 3 families remaining with us who wanted to spend the summer here.” (Neu-Herrnhut Diarium, manuscript in MAH, R.15.J.b.I.3.c, entry for May 21–23, 1795) In other terms, only special occurrences worth mentioning in the eyes of the missionaries and their authorities were recorded. Indeed, the diaries were sent back to Herrnhut for inspection by the Moravian authorities and to then edify the congregation. Thus, many of the entries provide justifications for the activities of the missionaries. It is notably in this context that they mention the weather to account for their meetings being cancelled because of adverse meteorological conditions, for example. This includes the indication of exceptional temperatures and extreme weather events likely to explain why something was not done, why the missionaries and/or the Greenlanders might be short of victuals, why a particular journey to an outpost was or was not undertaken, etc. Most of the time, the diaries account for events and developments at the station and in its vicinity, focusing largely on the congregation and its interaction with the Greenlanders, including also the life stories of missionaries and converts. Weather parameters are thus only mentioned, on the whole, if they were necessary to understand what happened to the missionaries, converts and other Greenlanders at one point or another. Nonetheless, for certain years and at a given station, the information may be more regular.
Whatever the case may be, let us now compare the information from Annalen der Physik and Periodical Accounts quoted above to what we find in the diaries. On 21 January 1790, the missionaries in Lichtenfels measured +5°R, “after a period of severe cold,” with temperatures dropping as low as −18°R on 19 December 1789, as the editors of Annalen indicate. In the diaries, the following data can notably be retrieved for the period mid-December/mid-January 1789/90: Dec. 19: −15°R, Dec. 20: −18.5°R (the data are thus slightly different in the review as far as the day and precise temperature are concerned), the diary adding “strong wind from the South”; 1 January 1790: −14°R, Jan. 3: “snowy weather from the north and biting cold” (N.B.: the term “snowy” was chosen to render the German word “Stöberwetter,” frequently used by the Greenland missionaries but somehow obsolete nowadays; in a German dictionary from 1814 one reads: “Stöberwetter, n. whether when the snow is drifted in fine particles, snow sprinkled weather”; see also “Stöbern, v. n. to fly like dust, to blow about like dust (of snow) to be driven, or drifted, through the air in very fine particules…” + “Stöberig, a. (said of snow) coming down in fine particles like dust, flying about like dust (of weather) snow-sprinkled, snowy,” Rabenhort’s Dictionary of the German and English Languages, London, 1814, part II, p. 388), Jan. 5: −17°R and “strong frost smoke”; Jan. 7: “storm from the south with so much snow that nobody could go outside and that no meetings could be held in the morning”; Jan. 8 “there was snowfall all day long”; Jan. 9 “the weather had cleared up […] and all brethren left to catch seal”; Jan. 11: “Towards the evening, the snow storm was so strong that no meetings of the congregation could be held”; Jan. 16: “clear weather and strong wind from the north, cold −14°R”; Jan. 20: “after several days of clear weather and biting cold, it became milder and began to snow”; Jan. 21: “Today, the thermometer indicated 5° above freezing point”; Jan. 22 “melting weather and wind from the south-east”; Jan. 24: clear weather and wind from the north; Jan. 25: snowfall all day long; Jan. 27: −15°R; Jan. 28 snowstorm – no meetings; Jan. 30: stormy weather from the south-east and strong snow fall during the night before; Feb. 3: −14°R; Feb. 7: +5° (Lichtenfels Diarium, manuscript in MAH, R.15.J.b.III.6).
Similarly, entries from the Lichtenau and Neu-Herrnhut diaries may complement the brief summary of winter 1792 in Periodical Accounts quoted above. Here are data from the latter: Dec. 23, 1792: stormy weather and strong snowfall all day “so that one could hardly go outside”; Dec. 30: yesterday biting cold, −15°R; Dec. 31, in the evening strong snow storm; Jan. 12: calm and mild weather, −3°R; Feb. 3: −19°R and strong smoke; Feb. 13: clear weather, −17°R; Feb. 18: “We have had severe cold and very strong frost smoke these past days, so much so that one could hardly see the land on the other side. The thermometer indicated these past days −15, −16, −17, −18 up to −19.5°R”; Feb. 22: severe cold continues; temperatures in the past days: −17 to −19 and even −20.5°R (N.B.: −20.5°R = −25.6°C).” (Neu-Herrnhut Diarium, manuscript in MAH, R.15.J.b.I.3.b)
To put these temperatures into perspective, the average minimum temperature in Nuuk for the period 1958–1999 was −10°C in January and −10.7° in February and March, the absolute minimum temperatures −29.5°C (in 1984), −28.5°C (1984) and −27.3°C (in 1983), according to a report published by the Danish Meteorological Institute (Cappelen, Reference Cappelen2001). In April 1797, exceptional cold was recorded in Neu-Herrnhut: temperatures dropping on the 9th to −20°R (=−25°C) – in comparison, the absolute minimum temperature recorded in Nuuk in April in the period 1958–1999 was −19.6°C (in 1997). Temperatures only became milder in early May, the missionaries noting that “since mid-December, there had been stormy weather and severe cold almost all the time” (3 May 3 1797). The diary of Lichtenfels also records “severe cold and northern wind” on the 9th, the sea “smoking very much,” adding “but the weather changed and became milder,” allowing some Greenlanders to come to the station on the 11th. Volume 5 of Periodical Accounts quotes a letter from Greenland mentioning an “uncommonly severe” winter 1811-12 (p. 376). In the Neu-Herrnhut diary, we find the following indications: 21 January 1812: +3°R, February 11: −19.5°R, Feb. 12: −23°R, on the fifteenth the cold lessens, Feb. 26: −0.5°R, Feb. 27: −15°R, Feb. 28: +3°R etc. The temperature of −23°R corresponds to −28.75°C, just slightly below the absolute minimum of −28.5°C measured in Nuuk in the years 1958–1999.
Once again, these are just some indications to show what may be found in the diaries, though the type of parameter and regularity may vary considerably from station to station and from year to year, depending no doubt also on who was keeping the diary at a given moment. To get a clearer view of what kind of weather entries occur when looking at several months in a row, a complete list of weather-related information was collected by the authors of this article from the Neu-Herrnhut diary for 1801 and translated (Neu-Herrnhut Diarium, manuscript in MAH, R.15.J.b.I.4.a):
2.1.1801: “These days, the cold was severe and continuous with 14–17° according to Ream with steadily increasing amounts of snowfall”; 4.1 “[…] although the cold was very severe”; 5.1.: “It was so snowy that no meetings could be held, which continued”; 6.1.: “on the Feast of Epiphany in the same way, nonetheless all the meetings were held”; 8.1.: “the harsh cold continued and it remained snowy, while the sea was smoking”; 10.1.: “In the evening, Br.[other] Grillich [Johann Georg Grillich, 1762–1842, Moravian missionary in Greenland from 1786] held the evening meeting but the meeting scheduled thereafter had to be cancelled because of the harsh cold.”; 19.1.: “[…] which could not be bought today because of the severe cold”; 20.1.: “since it became a bit milder”; 22.1.: “the severe cold ceased and at noon it began to rain”; 25.1.: “the weather was again very mild, all Sunday meetings could therefore be held”; 26.1.: “it was raining hard with southern wind”; 28.1.: “The Brethren caught some seals which caused great joy in these times of scarcity”; 10.2.: “in these days the weather was mild and fair, the sea very calm”; 13.2.: “however, all of them [the Greenlanders] reached home safely in the evening, while most of them, except a few who were particularly well-practised, had to wait on land all day long, before it calmed down in the late afternoon”; 18.2.: “The weather was mild and fair all day”; 9.3. “Since the weather turned fair, several Brethren left for Pissiksarbik [a fjord branching off Nuuk Fjord far inside the land] and other places to catch seal”; 17.3.: “a severe southern storm with snow appeared around noon, due to which evening meetings had to be cancelled”; 18.3: “It continued to blow so strong […] nonetheless many Brethren came back home from Kangek [one of the Greenlanders’ settlements, an island not far away from New-Herrnhut towards the open sea] with aulks and some others from Pissiksarbik with seals”; 24.3.: “very strong northern Wind and indescribably snowy weather 18 degrees according to Rom [according to Réaumur, often abbreviated erroneously “Rom”], with the sea roaring tremendously. There were therefore no meetings today, and since this” – 25.3.: “continued likewise today, one meeting was held in the evening”; 21.4.: “the still lasting cold and terrifying amounts of snow […] as if the cold could not cease […] Several who went far into the land to hunt dear, were telling us that there was far more snow there than here, which is why the hares were so skinny, since everything is covered in snow […]“: 26.4.: “The other meetings had to be cancelled because of the rough cold”; 27.4.: “[the weather] continued unchanged in the following days with 10–12 degrees according to Rom and strong northern wind, while it continued to snow heavily so much so that one was afraid to go outside and it seemed as if the real winter was only about to start, which the Greenlanders, just like us, had never seen around this time of the year.”; 1.5.: “The cold was particularly severe and hard to stand because of the strong northern wind, 13 degrees according to R. […] This cold continued/2.5. a./3.5. in the same way, until finally/4.5. the first signs of milder weather showed which had been long expected and longed for, which we were very grateful for”; 16.5.: “it snowed heavily again with a strong southern wind and quite severe cold, […] so much so that […][everything] had thawed because of the warmth of the sun was covered once again in snow and ice. Apart from that, the cold was so extraordinarily strong up north [presumably at Holsteinsborg (Sisimiut), just mentioned above, in the same entry] that the temperatures went lower than indicated on the thermometer, after they had counted 31 degrees according to Rom” (that’s − 38.75° C; according to DMI’s technical report, the absolute minimum temperature registered at Sisimiut in the years 1961–1999 was −38.8° C in February, −36.6° in March and −25.8 in April); 24.5.: “On Whitsuntide there was southern wind and such snowfalls that we could not hold any meeting in the evening”; 25.5.: “The whole land was covered again with new, deep snow; in previous years, we have always started sowing in the garden, but the top of the garden fence is only just to peeping out of the snow”; 30.5.: “it finally started to rain with a southern wind;” 31.5.: “which continued so heavily that streams were running everywhere”; 9.6.: “we were able to sow for the first time in our garden, even if the continuing rough weather and freezing temperatures at night time left little good hope for the growing [of plants]”; 19.7.: “These days the weather was fair and warm, so that it seemed the summer was only about to begin and our garden only just about began to recover nicely.” (Neu-Herrnhut Diarium, manuscript in MAH, R.15.J.b.I.4.a)
The exceptional weather during this period and its impact are summarised in Periodical Accounts: “The winter had continued with great severity and much snow, till the end of June. This occasioned a scarcity of seals, and our Brethren began to be apprehensive of a famine among the Greenlanders, but the Lord helped them graciously, that they experienced no want. In spring, violent colds and dysentries prevailed in New Herrnhut and Lichtenfels.” (Vol. III, pp. 46–47). Similar information could be gathered for other exceptional situations indicated in Periodical Accounts, but this would go far beyond the scope of the present article. In any case, the missionaries observed changes over a number of years in the early 19th century and commented on them in their correspondence, as Brother Grillich did in a letter sent from Neu-Herrnhut, dated July 10, 1817: “When Brother Mentzel [Heinrich Men(t)zel (1756–1816), Moravian missionary in Greenland from 1783 until his death] grew so ill, that his recovery was doubtful, we removed hither from Lichtenau, and perceive a great difference between the climates of the two places. That of Lichtenau is warm in comparison; and having resided there a long time, we very sensibly feel the roughness and severity of the winters of New-Herrnhut. The last has been very severe indeed. There was no difference between Christmas, Easter, and Whitsuntide. We lay buried in snow. Even now, being the 10th of July, hardly any thing has come up in our garden. The season here seems to have changed, and is become more unfavourable to vegetation. The winters are longer, the summer shorter, and the supply of drift-wood, more scanty than when our Mission was first established.” (Brother Johann Georg Grillich in Periodical Accounts, vol. VI, 447–448) Brother Johann Gottfried Gorke (1759–1842) in Lichtenfels notes in a similar vein on 2 September of the same year: “The state of the weather is getting worse in Greenland. Since our return to this country [July 30, 1813], we have not had one warm summer, as formerly. There were indeed more dry days in June and July, than last year, but the weather was much rougher and colder, insomuch, that our garden-crop is ruined. In August, it rained much, and now, in September, already it begins to snow. The quantity of drift-wood is greatly diminished, and the weather does not admit of our going in search of it. We are at a loss, how we are to be supplied with fuel for next winter.” (Brother Johann Gottfried Gorke in Periodical Accounts, vol. VI, 453) Michael E. Mann has suggested that “temperature variations in western Greenland in past centuries bear only a limited resemblance to those in Europe, which conventionally have best defined the Little Ice Age.” (Mann, Reference Mann and Munn2002, 505) To what extent the Moravians’ observations confirm or infirm the signature of the so-called Little Ice Age in western Greenland is a question to be discussed by climatologists. This is where the latter might wish to take over in order to specify which periods and parameters might be of particular interest to fill in gaps of Greenland’s weather chart.
Conclusion: interest of the data for climate studies
Although probably associated with large biases and inaccuracies, these observations, covering several decades of the so-called Little Ice Age, are undoubtedly of great interest for climate studies. The Little Ice Age period spanning roughly from 1350 to 1850 has been conventionally defined for Europe and regions bordering the North Atlantic Ocean. It is characterised by dramatic advances of mountain glaciers, particularly in the French and Swiss Alps and by colder conditions compared to the climatological mean. Although, the term “Little Ice Age” suggests a return to the climatic and environmental conditions of the Pleistocene glacial periods, glacier expansions and temperature drop were much more moderate, with a mean annual cooling of only 0.6°C for the Northern Hemisphere (Mann, Reference Mann and Munn2002) compared to several degrees during the last glacial period, 20,000 years ago. However, these change mask actually wide regional disparities both in terms of timing and amplitude of cooling (e.g. Forbes et al., Reference Forbes2020, Bradley and Jones Reference Bradley and Jones1993). Moreover, climate reconstructions from various proxy records (tree rings, pollen data, lake sediments, etc.) indicate that the colder and drier climate has alternated with warmer and increased moisture conditions (e.g. Kulkarni et al., Reference Kulkarni2018, Oliva et al., 2020). Outside Europe, the signal is even less clear because of fewer available proxies. Nevertheless, glacier advances have also been observed worldwide as well as cold winters. Yet, the precise timing of these events is highly variable from one region to the other with cooling episodes not necessarily synchronous with those observed in Europe (Neukom et al., Reference Neukom2014). As outlined by Mann (Reference Mann and Munn2002), putting all the proxy-based studies into perspective clearly shows that the Little Ice Age was essentially characterised by a large spatial and temporal variability making it difficult to draw up a global scale picture of the climate signature.
Many data covering the Little Ice Age period can be found for Europe. Conversely, for Greenland, observations are sparse and come mainly from ice cores. While the latter provide valuable archives of past climatic conditions, most of which are located in Greenland’s interior, little attention has been paid so far to low altitude areas and near coastal sites even if there are some exceptions. Thus, although the observations of the Moravian brotherhood are certainly associated with major shortcomings, they offer a unique testimony of the meteorological conditions in southwestern Greenland during the 18th and the first half of the 19th centuries. They notably provide indications of particularly cold years with long-lasting and harsh winters, as well as fresher than average summers. Reports of sowing and harvest dates can also characterise the duration of the spring and summer seasons and show how they deviate from the climatological mean.
Another very interesting aspect of these observations concerns the fact that when severe winters occurred in Greenland, mild weather conditions prevailed in Europe (and vice versa). As mentioned above, these conclusions have been drawn by Cranz from Brasen’s reports for the years 1766–1768. Similar findings were also later reported for the 1790s. This “bipolar pattern” is most likely related to the North Atlantic Oscillation (NAO), which is the dominant mode of winter atmospheric variability in the North Atlantic region, whose influence ranges from North America to Europe and parts of northern Asia. It is defined as a sea-level pressure difference between the subtropical high in the Azores and the subpolar Icelandic low. This difference controls the position of the jet stream and thus the pathway and intensity of the westerly winds in the North Atlantic region, but also the temperature of water masses and the intensity of oceanic currents. Marine observations, including the abundance of icebergs, are therefore of particular importance. When the pressure difference rises, there is an increase and a northward shift of the storm tracks crossing the Atlantic Ocean. This results in warm and wet winters in Europe and cold and dry conditions in northern Canada and Greenland. Opposite patterns of temperature and precipitation anomalies are typically observed when the pressure gradient is reduced. Thus, changes in the NAO phases may partly explain the climate variability during the Little Ice Age as well as the intervals of colder than normal conditions in Greenland, northern Canada or Europe.
Today, only indirect methods based on proxies of temperature and precipitation allow the reconstruction of past NAO phase variations from statistical relationships established for the present-day period. However, as pointed out by Ortega et al (Reference Ortega2015), such reconstructions are “challenging” because of the non-stationarity of these statistical relations. It is therefore essential to have cross-referenced information obtained both from different proxies and from historical documentation in order to obtain the most robust reconstructions of the NAO and to better characterise the regional disparities and the precise role of the NAO during the Little Ice Age.
Finally, among the most striking reports of the Moravian missionaries are the observations of extreme events (strong winds, storms, heavy snowfall events, etc.). Some of these could be related to volcanic events such as the Laki fissure eruption (Iceland) in 1783 which released huge amounts of volcanic aerosols in the stratosphere leading to colder conditions. However, no consensus has been reached so far in the scientific community on the causes of the Little Ice Age. It is thought that the climate of this period may have been caused by variations in solar activity, intense volcanic activity or changes in atmospheric circulation. The comparison of Moravian observations of extreme weather events in Greenland with those in other locations, such as Canada where historical records are also available, but possibly also other regions where the Moravian missionaries were active, would allow us to better characterise the amplitude and geographical extent of such events. They could then be compared with climate model simulations in order to better understand the respective roles of external (volcanism, solar activity) and internal (atmospheric circulation) forcings and the impacts of potential feedbacks within the ocean–atmosphere system. Indeed, because such extreme weather events are likely to occur in the future, it is therefore of primary importance to identify events due to natural climate variability and to distinguish them from those caused by anthropogenic activity.
