GLOBAL WARMING: THE HOLOCENE -3- Helluland, today's Baffin Island, and sailed from there southwa d 0 a1;1o~her island that he called V~nland ('vineland'). About /o0~ V1km?s under Thorfinn Ka~lsefm even began to settle in North America. The sagas re~or? this, and we also have the evidence of the GLOBAL COOLING: THE LITTLE Anse au~ Meadows site m Newfoundland excavated in the 1960 ICE AGE From this settlement numbering more than one hundred inhabitant'' furth~r voyages w~r~ made to the south. But the hostility of th~ Skrrelmgs, as the V1kmgs called native Americans, led to the collapse of the first European colony in the Americas. The sea routes frorn Greenland, not to speak of Iceland or Norway were too distant t lend it support.162 ' o The Concept of the Little Ice Age The term 'Little Ice Age' was coined in the late 1930s by the US glaciologist Fram;ois Matthes (1875-1949). It first appeared in a report on recent glacier advances in North America, 1 then in the title of an essay on the geological interpretation of glacier moraines in the Yosemite valley. Matthes was interested in the coolings since the postglacial climatic optimum, that is, over the last three thousand years, and especially in that which followed the medieval warm period. In his view, most glaciers still existing in North America do not go back to the last great ice age but have arisen in this relatively short space of time. The period from the thirteenth to the nineteenth century, in which glaciers advanced in the Alps, Scandinavia and North America, he called 'the Little Ice Age' (to distinguish it from the great ice ages). 2 The term was taken up in 1955 by the Swedish economic historian Gustaf Utterstrom (1911-85), who suggested a worse climate as the explanation for economic and demographic problems that Scandina­ via faced in the sixteenth and seventeenth centuries.3 His essay pointed to inadequacies in the argument of Fernand Braudel, the leading social historian of the time, who focused only on social factors. Eric Hobsbawm similarly concentrated on social-economic factors, inter­ preting the political crises up to the English Revolution as a history of class struggles.4 Nevertheless, this interest in 'the crisis of the sev­ enteenth century' drew fresh attention to the early modern period, whose centre was no longer sought in the Reformation or the French Revolution but rather in the crisis-ridden middle of the period. 5 84 85 GLOBAL COOLING: THE LITTLE ICE AGE THE CONCEPT OF THE LITTLE ICE AGE Rejecting the Durkheimian principle observed by social historians, Japan ~nd Korea, working within a tradition.that went back to late whereby the social is explained by the social,6 Utterstrom emphasized antiquity, recorded the absence of sunspots m the late seventeenth instead factors from outside the system of society: that is, the climate. century. In Europe, global cooling theories appeared more or less The French historian Emmanuel Le Roy Ladurie branded this essay simultaneously with the invention of the telescope, the building of an extreme example of the 'traditional method' (which he did not observatories and the systematic study of nature. The lesser number define more precisely) in the historical sciences .7 Yet, when he set of sunspots was interpreted as a sign of reduced solar activity and about refuting Utterstrom, he noted that the climate theory fitted linked to the cold spell that began in 1675. The cold phase between quite well the structural-historical interests of the Annales School,8 1675 and 1715 is called the Maunder Minimum, after the astronomer and that he himself had been infected with it. Ladurie took up serial Edward Walter Maunder (1851-1928), who collected and summa­ analysis of wine harvest data and, a few years later, published a rized observations made at the time.19 The solar activity hypothesis standard work on climate history that crucially rested upon Utter­ is one of the most elegant explanations, both for the Little Ice Age strom's proposals, drew heavily on scientific literature and made the as a whole and for its extreme years calculated by George C. Reid Little Ice Age more widely known.9 with the help of a climate model. 20 Since then the concept has aroused growing interest. In a number In the 1970s a group of Danish geophysidsts around Claus U. of major research projects, Hubert Horace Lamb (1913-97) in Hammer pointed out that the ice record indicates two clusters of England,1° Christian Pfister in Switzerland,11 Rudolf Bradzil in the intensified volcanism that coincide with the high point of the Little Czech Republic12 and Rudiger Glaser in Germany1 3 have so clearly Ice Age. In contrast to the sparse sulfate signal for the high Middle demonstrated climatic fluctuations in European history that their Ages, they found traces of the strongest volcanic activity since existence is now beyond all doubt. 14 As in the case of the high medi­ antiquity for the period between 1250 and 1500 and again between eval warm period, however, it is necessary to begin by mentioning 1550 and 1700.21 Our understanding of particular eruptions is only that we have to do here not with constant cooling but with a domi­ gradually increasing. Thus, analysis of 33 ice cores in Greenland nant tendency. Along with a large number of cold and wet years there and the Antarctic has dated to the year 1452-3 the explosion of were also periods of 'normal' weather and even some years of extreme the volcano Kuwae on Vanuatu, which preceded the 'global chill' heat. Many climate historians today cautiously define the period of of the 1450s.22 The eruption must have been more powerful than the Little Ice Age by climatic variability and frequency of extreme that of Tambora, but it caused major cooling only in the southern events.15 hemisphere. 23 Analysis of two weather diaries from Bavaria (Ingolstadt and Five volcanic eruptions have been identified for the precarious Eichstatt) for 1508 to 1531 has shown that winter temperatures decades between 15 80 and 1600; they too had an influence on Euro­ during the Reformation period were similar to those in the 1970s. pean history, even if most historians have never heard of them. These On the other hand, for the decades after 1563, a clear fall of 2 degrees were the eruptions of the Billy Mitchell volcano at Bougainville Celsius in average temperatures is observable in the Zurich area - a (Melanesia) in 1580, of Kelut on the island of Java in 1586, of Raung cooling event typical of the Little Ice Age. 16 In a medieval perspective, on Java in 1593, of Ruiz in Colombia in 1593, and of Huaynaputina a distinct climatic period may be said to have begun around the year in southern Peru in 1600.24 Only the last of these is also known to 1300 that had little in common with the warm high Middle Ages; us from extant sources, kept by the Spanish colonial authorities, and and in the second decade of the fourteenth century began the Little we can date it precisely to 19 February 1600. It devastated large areas Ice Age .17 within a radius of twenty kilometres, sent ash raining down on Peru, Bolivia and Chile,25 and entered the stratosphere with such effect that solar radiation was reduced worldwide over the following months. 26 Possible causes of the global cooling Harvest failures and famines occurred in the global wake of this The causes of the Little Ice Age are uncertain, first of all because of event. More generally, climatologists have worked out that eight the paucity of sources.18 A decline in solar activity is usually regarded periods with especially cool summers are linked to eight major vol­ as the main explanation for the global cooling. Observers in China, canic explosions.27 86 87 GLOBAL COOLING: THE LITTLE ICE AGE THE CHANGING ENVIRONMENT uch more difficult to prove a worsening of the climate. Something The Changing Environment :hich may appear in geological terms as a single process of cooling, because glacier formation and sedimentation take place over decades Worldwide glacier growth and increased aridity or centuries, is more difficult to demonstrate at the level of daily life. The grand old lady of glacier research, Jean Grove (1927-2001), to for people living at the time, short-term changes had greater impor­ whom we owe the first book specifically on the Little Ice Age 2s cance than medium to long-term ones. So we find in their records emphasized in her review of ice core records from around the world more observations about the weather than about the climate; they that a climatic optimum in the high Middle Ages was followed by were attentive to very cold spells, long winters with much snow or several centuries in which waves of cooling led to new glacier persistently icy conditions.34 Local chroniclers did make comparisons advances. This was a worldwide phenomenon, even if it was not over longer periods, and priests referred to the monstrous masses of always completely synchronous. Grove placed the onset of global snow for their spiritual exhortations.35 In 1624, after one extremely cooling in the early fourteenth century, and even a few decades before Jong and hard winter, the Thuringian clergyman Martin Pezold (d. that in the far north. 29 The high glacier level lasted, with ups and 1633) even put together a chronicle of European extreme winters in downs, until the end of the nineteenth century. 30 his book of Schneegedancken or 'snow thoughts'.