Byzantine : a ‘laboratory’ for the study of climate Avkat Archaeological Project impacts and socio-environmental relations in the past J. Haldon,1 N. Roberts,2 A. Izdebski,3 D. Fleitmann,4 M. McCormick,5 M. Cassis,6 O. Doonan,7 W. Eastwood,8 H. Elton,9 S. Ladstätter,10 S. Manning,11 J. Newhard,12 K. Nichol,13 I. Telelis,14 E. Xoplaki15 1 History Department, Princeton University, USA, 2 School of Geography, Earth and Environmental Sciences, Plymouth University, UK, 3 Institute of History, Jagiellonian University in Krakow, Poland, 4 Department of Archaeology, School of Archaeology, Geography and Environmental Sciences, University of Reading, UK, 5 Department of History, Harvard University, USA, 6 History Department, Memorial University of Newfoundland, Canada, 7 Department Of Art, California State University Northridge, USA, 8 School of Geography, Earth & Environmental Sciences, University of Birmingham, UK, 9 Department of Ancient History and Classics, Trent University, Ontario, Canada, 10 Österreichisches Archäologisches Institut, Vienna, Austria, 11 Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology, Cornell Tree- Ring Laboratory, Cornell University, USA, 12 Department of Classics, College of Charleston, USA, 13 Department of Geography, University of Utah, USA, 14 Research Center for Greek and Latin Literature, Academy of Athens, Greece, 15 Climatology, Climate Dynamics and Climate Change, Department of Geography, Justus-Liebig-University Giessen, Germany, [email protected]

INTRODUCTION

The issue of how environmental, especially climatic, disruptions affect hu- man societies and political systems has begun to attract a great deal of at- tention from the scientific community and the general public. Recent studies suggest that one possible result of certain climatic events is an increase in violence over contested resources -a conclusion that has significant conse- quences for, at least, policymakers, investment bankers, insurance compa- nies, and the military. We examine cases in which high-resolution archaeological, textual, and en- vironmental data can be integrated with longer-term, low-resolution data to afford greater precision in identifying some of the causal relationships un- derlying societal change. Fig. 2. left Statistically significant spatial correlations between the NAOI and winter pre- The spatial focus is the Byzantine world and in particular, the heart of that cipitation in the Eastern Mediterranean (1951–2006), along with palaeoclimatic sites world for several centuries, Anatolia. Through regional and microregional (Adapted from Roberts et al., 2012); right Changing borders of the East Roman Byzantine case studies we address some of the challenges and promote further collab- Empire, along with archaeological survey sites. Haldon et al. (2014) oration between historians, archaeologists, and climate scientists.

HISTORIOGRAPHY, METHOD, HUMAN ADAPTATION AND & INTERDISCIPLINARITY CLIMATIC CHANGE Fig. 1. Proxy records of temperature from Central Europe, climatic moisture Understanding how society and the environment have evolved over multi- conditions in central and western Anatolia and historically documented cli- Palynological data from decadal timescales to create modern landscapes can be achieved through mate-related events. Shaded bars mark notable periods of dry climate. Georgia and Iranian integrating instrument, document, palaeoenvironmental and archaeology Haldon et al. (2014) records within regions to produce socio-environmental profiles (PAGES). Azerbaijan across to the and the Levant Historians understand causal relationships from the point of view of multi- shed light in the Beyşehir plex interrelated social, economic, and political factors. Climate scientists Occupation Phase (BOP). think in terms of environmental impacts on agriculture, warfare, demo- Although BOP began and graphics, and long-term stability. Scholars of past climates have a range of THE CASE FOR ANATOLIA ended in different places tools at their disposal; proxy data deriving from biological and geological at different times, it climate archives as tree rings, stalagmites, and marine and continental sedi- roughly dates from the ment sequences. Historians can misconstrue or misuse the environmental The Anatolian case challenges a number of assumptions about the impact of “Minoan Warm period” data, generalizing from limited datasets or misappropriating low-resolution climatic factors on socio-political organization and medium-term historical ca. 1500 B.C.E. to the data insensitivity. evolution. Byzantine Anatolia has three vital types of data in abundance - written, archaeological, and palaeoenvironmental (Table I). markedly cooler 7th /8th Open issues for the study of the causal connections between political and century C.E (solar mini- social-cultural evolution and climate at all times are: mum), identified through Table I Data Sources and Characteristics • Chronological resolution the evidence of pollen Fig. 3. Sites with pollen data for the first millennium Type of found in lake beds. The C.E. in central and western Anatolia. 1 Bafa, 3 Köyce- • Spatial scale Written Archaeological Palaeoenvironmental Evidence debate about the end ğiz, 10 Beyşehir, 11 Hoyran. Haldon et al. (2014) • Climate as a causal element manuscripts, coring of lakes and date for the BOP is expli- excavation, surface survey, archived peats, tree-ring analysis, • Quantity and scope of available evidence Origin of data or studies of standing cable only partially by the imprecision of the chronologies derived from the documents, speleothems, and other monuments various data sets. The pollen at the sites of Lakes Beyşehir and Hoyran sug- inscriptions, seals natural archives • Quality of palaeoclimatic data gest a date in the middle years of the 6th century (Fig. 3). Those at Lake Bafa editing, source artefact or monument Different disciplines have different styles: scientists seek to reduce causality Preparation for laboratory analysis and on the Aegean Coast and the one at Köyceğiz on the southern coast indicate criticism, analysis, statistical interpretation statistical calibration to simple terms, as temporal coincidence or statistical correlation, whereas translation processing of data that BOP-type agriculture ceased during the later 3rd or 4th century. historians deal with complex processes and are wary of oversimplification. submonthly to decadal to century Although anthropogenic factors probably played a major role in the appear- Dating precision decadal to century Neither climate scientists, historians, nor archaeologists are in a position by subannual (occasionally annual) ance of the BOP, a beneficial climate régime must have had something to do themselves fully to integrate the vast range of data necessary for a multi- typically with it; thus, the relationship between human and climatic factors still needs semicontinuous and Time duration discontinuous or normally continuous and causal analysis that explains rather than simply describes. More local and normally multi-century to be addressed. and continuity of short (<100 yr) long duration regional studies are needed to test methodologies, collect multidisciplinary duration data, and ultimately derive holistic interpretations. duration identifying periods with stable socio-economic and reconstruction of identifying periods of Customary ways cultural-material events, historical different environmental of interpretation characteristics, model building and climatic conditions CLIMATE AND THE WIDER reconstructing changing settlement pressure GATHERING THE DATA detailed info on quantitative and qualitative PERSPECTIVE specific events, reconstructions of data on socio-economic and phenomena, and environmental and Across western Anatolia, Subject cultural transformations in Human activity has arguably had a greater imprint on the landscape than a- processes -social, climatic change via the long duration; pollen from flora repre- ny other single factor, particularly with respect to the way in which defore- economic, proxy evidence demographic estimations sent both human activi- station and over-grazing have led to soil exhaustion, erosion, alluviation, cultural, political ities and the natural ve- and land abandonment. The climate history of the region from possibly detailed inferential, normally site- or inferential, often Climate-society getation that replaces explanatory area-specific (excavated or achieved by temporal into the medieval and later times is presented in Figure 1. causality mechanisms surface materials) correlation crops or expands to oc- The Roman Warm Period (RWP; 3rd to 2nd century B.C.E. into the late 2nd cupy formerly tilled land and thus suggesting agricultural patterns. century C.E.) was typified by conditions that minimized much of the usual Anatolia and the southern Balkans are subject to three large-scale circula- risk and decadal variability associated with Mediterranean climate, coinci- tion systems that affect the region at different times of the year -the North Anatolia’s arable and ding with the growth and consolidation of Roman military and political po- Atlantic system, the South Asian summer monsoonal system, and the con- pastoral land was, with wer and economic expansion. In parallel, such conditions were also particu- tinental winter climate system, anchored over western Russia, and Siberia. regional variations, put larly favourable to the advance of agriculture and the increase in population Anatolia also contains a wide range of geographies, from open lowlands to relatively intensive across central and northern Europe. A detailed examination shows signifi- and upland plains to mountains, forests, and steppes, as well as significant use during the 6th and cant climatic variations both in time and in space during this period; the variations in climate. Some parts of the area have extremely cold winters 7th centuries. Both the RWP was not warm and wet everywhere all the time. Just as the Medieval with considerable snow, while others have mostly damp winters; summers palynological and the Warm Period is now more commonly referred to as the Medieval Climate vary from damp and hot to dry and extremely hot. archaeological eviden- Anomaly, it is likely that the RWP should similarly be re-evaluated. ce indicate that much of Central and western Anatolia, along with , show a notable spatial Fig. 4. Synthetic summary diagram of vegetation, the region was densely After the 2nd century C.E., a series of changes in regional climate patterns coherence of temperature and precipitation during the instrumental period. land use, and climatic change from Nar Gölü, inhabited and character- continued across the 5th and 6th century, and well into the 7th century, Such coherence is also likely to have been the case during the last two , 300-1400 C.E. Haldon et al. (2014) ized by mixed farming. marking the end of the relative stability of the RWP; the impacts varied by millennia (although the southern Levant has shown an opposite pattern). Following this period, Anatolia evinces a much simplified agro-pastoral regi- north and south and by east and west, as well as by time. The fact that this same area broadly coincides with the extent of Byzantine me and a reduced level of activity. The wholesale retreat and the reduction To what extent the different historical trajectories of east and west can be Anatolia between c. 660 C.E. and 1071 C.E. permits us to map the two in farming might indicate a reduced rural population in areas. The political tied to these different climatic trends remains to be seen, although some directly onto each other (Figure 2). distinct causal connections have been posited. The current state of our and economic recovery of the Empire during the later 9th and 10th centur- knowledge of these changes across several centuries is still sketchy, given ies coincides with the end of a drier (and cooler) period that started the 8th both the absence of data from many areas and inadequate chronological century and the expansion of large-scale pastoral farming, the reappearance control within some datasets, leaving a good deal of the dating uncertain. of cultivars, also traces of vines, olives, and fruits. The palynological data Despite the incompleteness of the regional pattern beneath the general from Nar Gölü indicates a significant agrarian recovery during the second trends, approximate parallels between climatic history and the evolution of CONCLUSIONS half of the 10th century C.E., presenting a new configuration in the region’s states and societies suggest that climate and environment should figure rural economy. In the 960s, Drizion (south Nar Gölü) was a productive and prominently in an integrated interpretation of past events. wealthy imperial estate that had only recently become safe from hostile at- A better understanding and a more effective interrogation of the rel- tack, after years of warfare and conflict. Anatolian landlords began to invest ationship between environment, society and historical change can be in expanding their estates, coinciding with the height of imperial political achieved through further collaboration among historians, archaeol- and military power and expansion and widespread growth of the agrarian ogists and climate scientists. economy in the Byzantine world. Was the degree of this improvement in the REFERENCES economic, political, and military fortunes of the Empire aided by an amelio- Integrated regional and chronological synthesis, in the context of a ration in the climate regime? broader picture, is an excellent platform on which historians, archae- ologists, and environmental scientists can work together to interro- A persuasive universal explanation for these developments is still elusive. Haldon, J. et al. (2014, in press) Journal of Interdisciplinary History. gate evidence of causal and explanatory relationships for long-term Most of the above shifts coincide neatly with known political events, such as the Arab-Islamic invasions from the late 7th century. Moreover, not all of the Roberts, N. et al. (2012) Global and Planetary Change. socio-environmental change. “climate change” events fit perfectly with other types of events.