Methods in World History: A Critical Approach

CHAPTER 1

Historians, superhistory, and climate change

J.R. McNeill

That we are now in an age of rapid climate change is disputed in only in a few places, and there mainly for political purposes. Concern over what changing climate might mean has motivated a surge of research into climate history, using all manner of proxy evidence to inquire into temperature conditions, droughts and floods, the frequency of hurricanes and other major storms, El Niño events, and much else besides.

Only a small proportion of this new evidence on climate history comes from textual sources, the familiar terrain of the historian. Instead it comes from tree rings, ice cores, speleothems (mineral deposits in caves), fossil pollen, marine corals, varves (layers of silt or clay on the seafloor) among other places. Climate history is undergoing a renaissance thanks to all these new data. At the same time, as I will explain below, new evidence of other sorts, pertaining to other sorts of history, is also cascading forth.

Fifty or sixty years ago, under the influence of Fernand Braudel and his friends, professional history took a turn toward the social sciences. Thirty years ago, under the influence of other French scholars, no friends of Braudel, professional history took a linguistic turn. Now it looks to be taking a natural science turn. Historians seem to be rather like windmills, turning this way and that in response to the prevailing winds of other intellectual disciplines. There is nothing wrong with that. Surely it is often preferable to adjust one’s research methods in response to innovations, whether they come from physics or from literary studies, rather than to remain resolutely unaffected by changes in intellectual life.

In this chapter, I will try to explain some of the opportunities and challenges presented by the volcano-like eruption of new historical data from the natural sciences, with special attention to climate data and what some prominent historians have thought about climate. I will also raise the question of how the new data might affect the choices historians make about the scales on which they pursue their research, in particular the logic of selecting a global scale.

Superhistory and why historians need to overcome the text fetish

The past, always a foreign country, is growing more foreign to textbased historians.

If historians wish to improve their – our – ability to address puzzles from the past (and for that matter to remain central in the study of history), they – we – need to embrace what is fast becoming superhistory. Superhistory amounts to a methodological revolution by which textual evidence jostles together with that of ice cores, marine sediments, peat bogs, stable isotopic ratios, and the human genome – and a few other genomes as well. The revolution takes historians to new terrain, to geo-archives and bio-archives, as well as to the more familiar archives containing old documents. Climate history is part of this revolution, so far perhaps the biggest part.

While careful analysis of documentary texts is the bread and butter of the historical method, historians for at least a century have found ways to use other sources such as art, literature, and the findings of archeologists. For those times and places at which abundant texts, art, and archeology overlap, such as the Roman Mediterranean of the first and second centuries CE, the interplay among specialists using different sorts of sources is a long tradition and a fruitful one. Such melding of sources has yielded information and insights rarely matched for times and places with fewer texts, less surviving art, or low appeal to archeologists. So superhistory has its precedents, and perhaps should be regarded as an expansion upon a methodological tradition (Myrdal 2012).

Superhistory nudges us, and perhaps drives us, in the direction of global history. Texts come in languages, and those languages sometimes correspond to political structures such as states and nations. Japanese is spoken in Japan and almost nowhere else; similarly with Danish and Denmark. Thus text-based historians who know these languages are tempted to write their histories on the national scale or smaller. Moreover, much textual documentation has been produced by bureaucrats employed by states and concerns the business of states. Thus textual history – what we still call history – exhibits a strong bias toward the affairs of nations and states. It encourages historians to accept nations and states as appropriate units of analysis, which for some questions they are and for others they are not. This tendency towards national-scale history has probably weakened in recent decades; the advent of superhistory will weaken it further.

The evidence of superhistory bears much thinner relationships to nations and states, and encourages historians to play around with other units of analysis, both larger and smaller. Of course, textual historians for centuries have worked on a variety of scales. Some attempted global history or thematically defined subsets of global history, such as warfare, marriage, or agriculture. The new torrents of climate evidence and the genomic data easily lend themselves to global-scale analyses. Thus the evidence from the natural sciences that is now spewing forth invites a new generation of historians to adopt world-historical perspectives. And those scholars already employing world history perspectives probably find the new evidence of superhistory more interesting, exciting, and compatible with their ambitions than do other historians.¹

Superhistory bears a cousinly resemblance to Big History. Scholars such as David Christian (in Australia) and Fred Spier (in the Netherlands) have spearheaded a very long-term perspective on human affairs, which they call Big History. It involves situating the human story inside the story of life on Earth, inside the story of Earth, inside the story of the solar system, our galaxy, our Universe. At this scale, mind-boggling for most historians, Christian and Spier find patterns that are not readily visible on the brief time scales familiar to historians and archeologists. They see, for example, recurrent stories of energy capture and advancing complexity, in celestial bodies and civilizations alike, over time (Christian 2005; Spier 2010).

Big History, moreover, necessarily requires a plurality of sources, disciplines, and perspectives. Big historians such as Christian (a historian of imperial Russia by background) and Spier (an anthropologist with an undergraduate degree in biochemistry), must wrestle with cosmology, astronomy, earth science, evolutionary biology, paleoanthropology, archeology, as well as history as conventionally understood. Big History is stunning in its ambition, and requires an Aristotelian reach on the part of its practitioners. No wonder there are comparatively few who practice the art.

Superhistory calls for something less. First of all, it is not concerned with the origins of the Universe, stars, planets, galaxies, solar systems, or life. Nor is it concerned with much of the first four billion years of life on Earth. Rather, it is concerned with the human experience and only the human experience. It is a few notches less ambitious, and less demanding, than Big History. But it shares with Big History a recognition of the value of approaches to the human past through multiple disciplines and multiple types of sources. In this chapter I maintain that historians, like it or not, would be well advised to accept the implications of superhistory and acquaint themselves, where appropriate to their subjects, with the evidence from the natural sciences. But I do not claim that they need to become practitioners, or devotees, of Big History. While I have the greatest respect for the achievement of Christian (2005) and Spier (2010), and am among those fascinated by the larger patterns they identify, I do not yet see that their elegant nesting of human history inside so many other histories necessarily changes the way historians should see their subjects. In a sense, Big History changes everything and changes nothing. It tells us that our species’ story conforms to a larger pattern. But it does not change our species story. In a nutshell, superhistory represents a revolution in historical methods but no change in subject; Big History is a revolution in subject, perspective, and method.

Before going any further, let me turn to some of the dark sides of superhistory. Among the risks one runs in globalizing history is the temptation to seek simple explanations for things outside one’s area of expertise. This temptation operates within history itself, and a fortiori with respect to scholars venturing beyond its traditional confines and dabbling in superhistory. So, historians of modern or late imperial China for example, who would never accept a simple explanation of the fall of the Qing dynasty, are tempted to accept one for the fall of the Maya city-states or for the empire of Mali. This is only human: it would take time and effort to educate oneself in the complexities of Yucatan and Guatemala in the eighth to the tenth century, or West Africa in the fourteenth and fifteenth. Who can justify the time?

Historians who forage in other disciplines to enrich their sense of the past run a still greater risk. Climatology, genetics, historical linguistics, isotopic analysis, and other specialist realms, of course have their complexities and controversies, and informed assessment of them requires some considerable education in fields most historians have steadfastly avoided since secondary school. Hence the powerful temptation to accept simplistic explanations – or, what is probably worse, to ignore novel sorts of evidence and pretend that texts are all that matters.

That last position, while comforting to those of us trained to examine texts, is increasingly naïve and intellectually unsustainable. By fetishizing documents, professional historians for nearly 200 years have presented caricatures of the past based on what were often accidents: what happened to get written down, and, of that, what happened to be kept, and, of that, what happened to survive rot, fires, floods, ravenous insects, important people trying to hide a sin or two, or any of the several other hazards to which paper, papyrus, clay tablets, or oracle bones might be subject. As a result, a great deal remained hidden to historians, many of whom found it congenial and comforting to pretend it therefore did not happen.²

Confining oneself to data present in texts is now a worse method than ever before. Nowadays the chemically-inclined physical anthropologists can tell us, by examining strontium-calcium ratios in bone and teeth, where the food was grown that nourished any particular body. They can tell which alpine valleys Ötzi the Iceman frequented during his childhood, and, if given a tooth, could tell us whether or not President Obama was raised in Hawaii and Java as opposed to Kenya, as a remarkable proportion of Americans believe (not that strontium-calcium ratios would likely change their opinions in the matter!). They can tell us, from chemical analysis of human remains, that Italians in 900 CE ate almost no seafood unless they lived on the coast, but that by 1300 even inland Italians ate it routinely.

The microbiologists can tell us which antibodies prevailed in which populations, providing indications of past experience of bubonic plague or malaria. From teeth, they can tell us which skeletons in London cemeteries from 1348 belonged to bubonic plague victims and which did not. They can map the geography of the 1918 influenza epidemic’s intensity at least as well as can historians working with texts. The geneticists can tell us that the founding mothers of the Icelandic population were overwhelmingly from Britain and Ireland, presumably abducted or purchased by Norsemen en route to settlement in Iceland in the decades after 874 CE, something on which the Icelandic texts are mute and archeology unhelpful.

Microbiologists and geneticists have also resolved what for Americans was a detail of some importance: that Thomas Jefferson did indeed father children by a slave woman named Sally Hemings. Jefferson’s paternity of Hemings’ children, once widely doubted, is now denied only by his fiercest apologists. It is not merely the distant past that new methods illuminate, although their value is indeed greater in that very foreign country because of the paucity of texts.

It may be disconcerting for most of us, but history is in the throes of a methodological revolution or two, one for which none of us are trained and few of us prepared. To the extent that we shy away from it, we will be shunted further to the margins in some of the important debates of our time, such as that over the significance of climate change, and – incredible as it may seem to historians – perhaps also in some discussions of the past. To the extent that we embrace it, we will have a voice in all these conversations.

I will finish this discussion with a cheerful example of the promise of superhistory drawn from my own experience. While a doctoral student in the early 1980s, I grew interested in the history of yellow fever in the Caribbean. At that time, no one knew if yellow fever was originally an American or an African disease, no one knew whether its vector, a particular species of warmth-loving mosquito, was American or African, and no one knew why the texts seemed to show a stronger prevalence of the disease in the eitghteenth and nineteenth centuries than before. (I should also say that as far as I could tell no one other than myself seemed to care about that last point.) I wrote an amateurish paper on yellow fever in the Caribbean, thinking I would follow up with more research soon.

Fortunately for me, I let life intervene for a quarter century before I returned to the subject. In the interim, geneticists had shown that the yellow fever virus circulating in the Americas is of African origin; and that the vector mosquito is also a migrant from Africa. These new data help explain the immunological basis for a racist discourse of difference between Africans and others in the Caribbean, one that claimed Africans were more fit than others for labor in the torrid zone. (Being African or black was widely thought to be important but in fact was irrelevant; disease resistance to yellow fever was based on whether or not one spent one’s childhood in an endemic yellow fever zone such as most of West Africa – and perhaps whether one’s ancestors over hundreds of generations had done so. Many Africans and many blacks had neither acquired nor heritable resistance to yellow fever.) But many did carry immunity to yellow fever, and resistance to malaria as well. And so once these diseases became established and endemic in the West Indies (by about 1650), it seemed to most observers (or, more precisely, to those whose opinions happened to get written down and preserved) that African bodies were by nature suited for labor in the Caribbean.

Meanwhile, historical climatologists studying the chemistry of the shells of sea creatures had shown that the warming at the end of the Little Ice Age (already known as a European phenomenon in my student days) extended to the Caribbean. As the Caribbean got warmer, conditions improved for the yellow fever mosquito. Vector abundance, as specialists put it, is crucial to the prevalence of mosquito-borne diseases, so climate’s suitability from the mosquito point of view was an important factor affecting the risk presented by yellow fever. Climate scientists, in the interim, also had constructed a database of El Niño events over the centuries, allowing respectable hypotheses about drought frequency and varying conditions for mosquito breeding.

So, by 2005, without having done any of the research myself – which indeed I was not competent to do, having sidestepped microbiology and climate science in my education – I was in a much stronger position to make sense of the fragmentary textual record concerning yellow fever outbreaks available in a handful of archives. All I had to do was read the recent work of a handful of scientists. And the book I wrote on these subjects was more convincing than it could have been in 1985, thanks to the emergence of new data from the natural sciences – convenient bits of superhistory (McNeill 2010).

Natural scientists provided these convenient bits of superhistory not because I wanted them, but because such research suited their own agendas. Had it been up to me, I would have asked for research on some other issues pertaining to yellow fever as well (particularly the unresolved issue of whether or not there is any heritable resistance or even immunity to the disease). Unfortunately for me, I was not in a position to direct the efforts of microbiologists and geneticists. Few historians, if any, will ever be in that position. This, then, is a limitation of superhistory: the findings pouring forth result from research agendas that historians do not shape, and generally do not even influence in the slightest. But this is only a limitation. And if historians join interdisciplinary research teams before those teams fully set their research agendas, the odds of affecting those agendas improve dramatically. This limitation is not reason enough to scorn the data of superhistory.

Why historians need to elbow their way into the climate change debates

A big part of the new superhistory, and the only part I will deal with henceforth, concerns the history of climate. So far the archeologists and paleo-anthropologists have gone further than historians in taking historical climate change seriously. There are several possible reasons for their eagerness to embrace climate change in their work. One is that they live off research grants to a larger extent than do historians, and to elbow their way to that feed trough amidst the legions of cancer researchers and hunters of the Higgs boson, they need to make plausible claims to be doing relevant and useful science. And among the few routes open to them is to offer results that speak to societies’ experience with climate change. A second possible reason is that because they typically deal with sparse evidence – a few bones and potsherds – any new evidence looms large for their interpretations.

Historians, at least most of us, do not compete at the same trough as natural scientists. Our survival is not so directly tied to providing useful science, so our quests for funding do not propel us toward the issue of climate change. And most of us, at least, do not thirst for new kinds of information. We have enough of the old sort to keep us occupied. There is no shortage of texts awaiting examination or re-examination in light of new concerns. But all that, like the limitations mentioned above, is not reason enough to shy away from the new data offered by natural scientists, especially on climate.

Scientific American, an excellent popular science magazine, recently printed a fine overview article on current climate change and its implications. The author, a distinguished earth scientist from one of the world’s foremost research universities, makes several trenchant arguments for the importance of the ongoing pulse of climate change. Then he writes:

Human civilization is also at risk. Consider the Mayans. Even before Europeans arrived, the Mayan civilization had begun to collapse thanks to relatively minor climate changes. The Mayans had not developed enough resilience to weather small reductions in rainfall. The Mayans are not alone as examples of civilizations that failed to adapt to climate change (Caldeira 2012: 83).

This is all he says about the potential significance of climate change for humankind. And, unfortunately, it is probably mostly wrong. According to current expert opinion, the Maya collapse – if that is the right word for it – consisted of a decentralization and de-urbanization that took place over several decades in the ninth and tenth centuries. It was bad for ruler, but ordinary Maya might well have regarded it as a liberation. (They left no texts so we cannot know for sure). Royal demands for tax and conscripts disappeared. With respect to climate, a severe and prolonged drought, one of three Central American megadroughts of the past 2,000 years – not small reductions in rainfall – deflated the rural economy. Many things contributed to the collapse; specialists point to soil erosion, increased warfare, and half a dozen other unfavorable trends. And so to say it occurred thanks to relatively minor climate changes is doubly wrong – the climate changes were major and they provide only part of any explanation. Lastly, resilience to fluctuations in rainfall was probably among the strengths of the Maya, who had sophisticated water management (Stahle et al. 2011; Beach et al. 2015).

The Scientific American article (Caldeira 2012) illustrates some of the hazards of interdisciplinary work mentioned above. The author accepted blithe assertions about the Maya, without probing the specialist literature. Perhaps he felt he was too busy to research an issue tangential to his article; perhaps he trusted a careless research assistant too much.

My point is not to castigate a distinguished earth scientist for writing a few sentences of ill-informed history, or not merely to do so. It is, also, to argue that historians must bring their skills and sensibilities to the issue of climate change. Otherwise oversimplified histories penned by earth scientists, journalists, environmental activists, and climate deniers will prevail unchallenged.

What have historians done with climate so far?

The great majority of professional historians for the last 200 years have completely ignored any possible significance of climate. In many cases, this neglect is justified: climate had nothing to do with King Henry VIII’s unhappy marriages or Marx’s debts to Hegel or any of countless other matters important to historians. But on bigger scales, when one considers the trajectories of regions and societies, this persistent neglect is surely unjustified.

When thinking about historians and climate, and about how climate affected human history, it is important to draw a fundamental distinction, one that historians, and others, have from time to time ignored. That distinction is between climate regime and climate change. By and large, until quite recently, among those who attributed any significance in human affairs to climate, it was climate regime, not climate change, they pointed to.

Once upon a time, most thoughtful and educated people believed the global climate was fixed. Some thinkers, from the time of Theophrastus – a student of Aristotle’s – if not before, thought that local climates might change. Aristotle himself in one passage implied climate had changed over the centuries in the Argive plain around Mycenae, and, further, suggested that pattern might be more general.

In the time of the Trojan wars the Argive land was marshy and could only support a small population, whereas the land of Mycenae was in good condition (and for this reason Mycenae was the superior). But now the opposite is the case, for the reason we have mentioned: the land of Mycenae has become completely dry and barren, while the Argive land that was formerly barren owing to the water has now become fruitful. Now the same process that has taken place in this small district must be supposed to be going on over whole countries and on a large scale.

This passage, so far as I know, is a rarity among ancient thinkers, who preferred to believe that climate was fixed except perhaps locally in response to loss of forest cover. (The indispensable guide to ancient environmental thought is Glacken 1967). And there is some difficulty of interpretation here: Aristotle did not mention climate specifically, even though the passage quoted above appears in Book I of his Meteorologica. Perhaps he had something else in mind, such as drainage. If Aristotle did have climate change in mind, as seems most likely to me, he was out of step with his age. The fact remains that (as far as the textual evidence can tell us) thinkers of the ancient world typically regarded climate as fixed rather than changeable. Modern historians, on the rare occasion when they gave the matter any thought, normally agreed.

Many deep thinkers, however, supposed that climate regimes shaped the essence of societies or the characteristics of peoples. Herodotus, Hippocrates, Aristotle, Ibn Khaldun, Montesquieu and thousands of shallower thinkers shared this view. The various bands of latitude, they maintained, each had their own climates, and each climate had its impact on people’s abilities or society’s characteristics. The fourteenth-century polymath from today’s Tunisia, Ibn Khaldun (1967: 58) for example, following the ancient Greeks, claimed