Climate and Culture in Enlightenment Thought

The debate over climate change, both from natural causes and human activity, is not new. Although the Baron C.-L. de Montesquieu is undoubtedly the best known Enlightenment thinker on the topic of climatic determinism, others, notably the Abbé Du Bos, David Hume, and Thomas Jefferson, observed that climatic changes exerted a direct influence on individuals and society and that human agency was directly involved in changing the climate. Climate—from the Greek term klima, meaning slope or inclination—was originally thought to depend only on the height of the Sun above the horizon, a function of the latitude. A second tradition, traceable to Aristotle, linked the quality of the air (and thus the climate) to the vapors and exhalations of a country. The Hippocratic tradition further linked climate to health and national character. As late as 1779, the Encyclopdédie of Denis Diderot and Jean le Rond D’Alembert defined “climat” geographically, as a “portion or zone of the surface of the Earth, enclosed within two circles parallel to the equator,” in which the longest day of the year differs in length on its northern and southern boundaries by some quantity of time, for example one-half hour. The article goes on to mention Montesquieu’s position on “l’influence du climat sur les mœurs, le charactère, et les loix des peuples.” The second definition of climate provided by the Encyclopdédie was medical, identified primarily as the temperature of a region and explicated through its effects on the health and well-being of the inhabitants. The idea that climate influenced culture was derived in part from the writings of ancient and medieval philosophers, geographers, and historians, including the works of Hippocrates, Albertus Magnus, and Jean Bodin. With no established science of climatology, Enlightenment thinkers apprehended climate and its changes primarily in a literary way. They compared the ancient writings to recent weather conditions, linked the rise and fall of creative historical eras to changes in climate, and promoted a brand of climatic determinism based on geographic location and the quality of the air.

Joseph Fourier’s Theory of Terrestrial Temperatures

The concept of the greenhouse effect has yet to receive adequate historical attention. Although most writing ahout the subject is concerned with current scientific or policy issues, a small but growing fraction of the literature contains at least some historical material, which, as this chapter shows for the case of Joseph Fourier, is largely unreliable. Jean Baptiste Joseph Fourier is best known today for his Fourier series, a widely used mathematical technique in which complex functions can be represented by a series of sines and cosines. He is known among physicists and historians of physics for his book Théorie analytique de la chaleur (1822), an elegant but not very precise work that Lord Kelvin described as “a great mathematical poem.” Most of his contemporaries knew him as an administrator, Egyptologist, and scientist. Fourier’s fortunes rose and fell with the political tides. He was a mathematics teacher, a secret policeman, a political prisoner (twice), governor of Egypt, prefect of Isère and Rhône, friend of Napoleon, baron, outcast, and perpetual member and secretary of the French Academy of Sciences. Most people writing on the history of the greenhouse effect merely cite in passing Fourier’s descriptive memoir of 1827 as the “first” to compare the heating of the Earth’s atmosphere to the action of glass in a greenhouse. There is usually no evidence that they have read Fourier’s original papers or manuscripts (in French) or have searched beyond the obvious secondary sources. Nor are most authors aware that Fourier’s paper, usually cited as 1827, was actually read to the Académie Royale des Sciences in 1824, published that same year in the Annales de Chimie et de Physique, and translated into English in the American Journal of Science in 1837! No one cites Fourier’s earlier references to greenhouses in his magnum opus of 1822 and in his earlier papers. Nor do they identify the subject of terrestrial temperatures as a key motivating factor in all of Fourier’s theoretical and experimental work on heat. Moreover, existing accounts assume far too much continuity in scientific understanding of the greenhouse effect from Fourier to today.

Introduction: Apprehending Climate Change

Apprehensions have been multiplying rapidly that we are approaching a crisis in our relationship with nature, one that could have potentially catastrophic results for the sustainability of civilization and even the habitability of the planet. Much of the concern is rightfully focused on changes in the atmosphere caused by human activities. Only a century after the discovery of the stratosphere, only five decades after the invention of chlorofluorocarbons (CFCs), and only two decades after atmospheric chemists warned of the destructive nature of chlorine and other compounds, we fear that ozone in the stratosphere is being damaged by human activity. Only a century after the first models of the carbon cycle were developed, only three decades after regular CO2 measurements began at Mauna Loa Observatory, and only two decades after climate modelers first doubled the CO2 in a computerized atmosphere, we fear that the Earth may experience a sudden and possibly catastrophic warming caused by industrial pollution. These and other environmental problems were brought to our attention mainly by scientists and engineers, but the problems belong to us all. Recently, policy-oriented social scientists, public officials, and diplomats have turned their attention to the complex human dimensions of these issues. New interdisciplinary and multidisciplinary collaborations have arisen between scientists and policymakers to examine the extremely challenging issues raised by global change. There has been a rising tide of literature—scholarly works, new journals, textbooks, government documents, treaties, popular accounts—some quite innovative, others derivative and somewhat repetitious. This has resulted in growing public awareness of environmental issues, new understanding of global change science and policy, widespread concerns over environmental risks, and recently formulated plans to intervene in the global environment through various forms of social and behavioral engineering, and possibly geoengineering. Global change is now at the center of an international agenda to understand, predict, protect, and possibly control the global environment. The changing nature of global change—the historical dimension—has not received adequate attention. Most writing addresses current issues in either science or policy; much of it draws on a few authoritative scientific statements such as those by the Intergovernmental Panel on Climate Change (IPCC); almost none of it is informed by historical sensibility.

Global Cooling, Global Warming: Historical Dimensions

I have chosen to conclude these essays just as the well-known IGY was getting started. Of course, much has changed since then. There is little to gain, however, by attempting to recount the recent policy history of global change, at least from my perspective as a historian of science and technology. I have tried in this book to provide fresh perspectives on the more distant past, not to replicate the recent literature on global change. Although I am actively engaged in projects sponsored by the American Meteorological Society and the American Geophysical Union that document the recent past, I have little inclination to attempt to interpret it. Consequently I include in this chapter only the briefest sketch of the global cooling scare after 1958 and the return of a global warming discourse in the 1980s. I believe the metaphor of apprehension (awareness, understanding, fear, intervention) applies quite well to a number of current environmental issues, and I will point to some of them by way of conclusion. I was asked once after a seminar whether, as a historian, I could predict the eventual demise of today’s global change discourse, since there had been so many changes in the past. I responded that history has no predictive value, but does indeed provide valuable perspectives to its readers. History is first and foremost the study of change. For students of global change, history can serve as an inspirational story of how far we have come. It can also serve as a humbling reminder that change is indeed inevitable in our lives, in the Earth system, and in our ideas and institutions. Although I am professionally engaged with the past, I am still a citizen of my own age—an age of vastly enhanced environmental awareness. Like many of my contemporaries, I believe that humanity is a part of, not apart from, nature; that human activity is placing tremendous stress on global biophysical systems; and that we have an ethical responsibility to each other and to future generations to live sustainably, in harmony with the Earth. Your guesses about the future are probably as good as and perhaps better than mine.

The Climatic Determinism of Ellsworth Huntington

The climate work of the unrestrained and undisciplined geographic determinist, eugenicist, and popular writer Ellsworth Huntington (1876–1947) can be categorized into three large themes: the influence of weather and weather changes on workers and students, the influence of climate on world civilizations, and the influence of solar variations on climate change. The first represented a sort of meteorological Taylorism, the second a reprise of enlightenment determinism, and the third a simplistic and wholly unrealistic pseudoscientific theory. Why, then, should we bother with him? One answer was provided by the historian Arnold Toynbee, who was “enormously influenced” by Huntington’s ideas about the relation between human beings and their physical environments. It was Toynbee’s opinion that “[s]tudents of human affairs may agree or disagree with Huntington, but in either case they will be influenced by him, so it is better that they should be aware of him.” Although Huntington’s thought was indeed influential in its time, since then his racial bias and crude determinisms have been largely rejected. Nonetheless, his categorical errors seem destined to be repeated by those who make overly dramatic claims for weather and climatic influences. Ellsworth Huntington was born in Galesburg, Illinois, on September 16, 1876, the third child and eldest son of Henry Strong Huntington, a Congregationalist minister, and Mary Lawrence Herbert. The Huntingtons were proud of their Puritan ancestry, which they traced to 1633. Following the call of the ministry, the family moved to Gorham, Maine, in 1877 and then in 1889 to Milton, Massachusetts, a wealthy suburb of Boston. Ellsworth attended the public high school, where he excelled in athletics and academics. His biographers have called him reclusive, but his brother suggested that perhaps he was humble rather than shy. Huntington passed the Harvard entrance examinations, but family finances precluded his enrollment there. Instead, he attended Beloit College, where he boarded with a maternal aunt, from 1893 to 1897. Following in the footsteps of T. C. Chamberlin (Beloit 1866), Huntington studied both classics and geology, publishing his first article, on local road-making materials, in the Transactions of the Wisconsin Academy of Sciences.

Climate Discourse Transformed

The impressionistic Enlightenment view of the American climate and its changes was rebutted in two distinct ways—literary and scientific. The literary critique was spearheaded by Noah Webster in 1799 and finally put to rest four decades later by Samuel Forry, a surgeon and climatologist in the United States Army. The scientific response came from pioneer climatologists who subjected the growing amounts of meteorological data to statistical analysis. Both approaches contributed to the radical transformation of climate discourse and, along with the expansion of meteorological networks, led to the emergence of a recognizably modern climatology. In his essay “On the Supposed Change in the Temperature of Winter,” Noah Webster criticized the “popular opinion” advanced by “many writers of reputation . . . the Abbé Du Bos, Buffon, Hume, Gibbon, Jefferson, Holyoke, Williams” that the climate of Europe and America, especially the temperature of winter, had become warmer in modern times. His critique emphasized their loose citation of sources, both ancient and contemporary, and the improper deductions they drew from these citations: . . . Men are led into numberless errors by drawing general conclusions from particular facts. “Lady Montague sat with her window open in January, 1718, and therefore there is little or no winter in Constantinople,” is very bad logic. The farmers on Connecticut River plowed their lands, as I saw in February, 1779; and the peaches blossomed in Pennsylvania. What then? Are the winters all mild in America? Not at all; in the very next year, not only our rivers, but our bays, and the ocean itself, on our coast, were fast bound with ice. . . . Webster was particularly critical of Samuel Williams, whose contention that Italy had warmed seventeen degrees in eighteen centuries was based on selective citations from ancient Roman writers. Williams erred in his assumption that reports of extreme weather were representative of ordinary conditions. Webster used historical accounts of the range of frost-sensitive plants—olive, fig, and date trees—to argue that Italy’s climate had not changed since antiquity and “could never have been colder than the Carolinas” and that its winters “were not severe, but mild.”

John Tyndall, Svante Arrhenius, and Early Research on Carbon Dioxide and Climate

In the second half of the nineteenth century two prominent scientists, working in two distinct specialties, identified the importance of atmospheric trace constituents as efficient absorbers of long-wave radiation and as factors in climatic control. John Tyndall conducted the first convincing experiments on the radiative properties of gases, demonstrating that “perfectly colorless and invisible gases and vapours” were able to absorb and emit radiant heat. Svante Arrhenius, in pursuing his interests in meteorology and cosmic physics, demonstrated that variations of atmospheric CO2 concentration could have a very great effect on the overall heat budget and surface temperature of the planet. It would be a mistake, however, to consider either of these individuals as direct forerunners or prophets of contemporary climate concerns. Each of them had extremely broad scientific interests and pursued climate-related research as one interest among many. Tyndall worked on absorption in the near infrared at temperatures far above those of the terrestrial environment. Arrhenius, who has recently gained renewed attention as the “father” of the theory of the greenhouse effect, held assumptions and produced results that are not continuous with present-day climate research. . . . The solar heat possesses, in a far higher degree than that of lime light, the power of crossing an atmosphere; but, when the heat is absorbed by the planet, it is so changed in quality that the rays emanating from the planet cannot get with the same freedom back into space. Thus the atmosphere admits of the entrance of the solar heat, but checks its exit; and the result is a tendency to accumulate heat at the surface of the planet. —John Tyndall (1859). . . John Tyndall was born in Leighlin Bridge, County Carlow, Ireland, on August 2, 1820, the son of a part-time shoemaker and constable. He attended the national school in Carlow and, at the age of eighteen, joined the Irish Ordnance Survey as a draftsman and surveyor. In 1842, as the Irish survey neared completion, Tyndall was transferred to the English Survey at Preston, Lancashire, but due to his protests against the survey’s oppressive policies and incompetent management, he was dismissed.

The Great Climate Debate in Colonial and Early America

Enlightenment ideas of climate and culture, developed in an era of European expansion, were stimulated by the writings of explorers, colonists, and travelers. Initially, colonists were confused and confounded by the cold winters and harsh storms. The New World was the object of considerable disdain for many European elites. Convincing them that the North American continent was not a frozen, primitive, or degenerate wasteland became a crucial element in American apologetics. The notion that a harsh climate could be improved by human activity—draining the marshes, clearing the forests, and cultivating the soil—was a major issue in colonial and early America and remained so until the middle of the nineteenth century. If the climate could truly be transformed, the implications were enormous, involving the health, wellbeing, and prosperity of all. There were contrarians, however, who called these ideas just so much wishful thinking. Early settlers in North America found the climate harsher, the atmosphere more variable, and the storms both more frequent and more violent than in similar latitudes in the Old World. In 1644–45, the Reverend John Campanius of Swedes’ Fort (Delaware) described mighty winds, unknown in Europe, which “came suddenly with a dark-blue cloud and tore up oaks that had a girt of three fathoms.” Another colonist in New Sweden, Thomas Campanius Holm, noted that when it rains “the whole sky seems to be on fire, and nothing can be seen but smoke and flames.” James MacSparran, a missionary to Rhode Island for thirty-six years until his death in 1757, spent considerable energy warning colonists against emigrating to America. He found the American climate “intemperate,” with excessive heat and cold, sudden violent changes of weather, terrible and mischievous thunder and lightning, and unwholesome air—all “destructive to human bodies.” While new settlers in all countries and climates are subject to many hardships, Dr. Alexander Hewatt observed that the hardships experienced by the first settlers of Carolina “must have equalled, if not surpassed, everything of the kind to which men in any age have been exposed. . . . During the summer months the climate is so sultry, that no European, without hazard, can endure the fatigues of labouring in the open air.”

Global Warming? The Early Twentieth Century

In the first half of the twentieth century, most scientists did not believe that increased CO2 levels would result in global warming. It was thought that at current atmospheric concentrations, the gas already absorbed all the available long-wave radiation; thus any increases in CO2 would not change the radiative heat balance of the planet but might augment plant growth. Other mechanisms of climatic change, although highly speculative, were given more credence, especially changes in solar luminosity, atmospheric transparency, and the Earth’s orbital elements. By the 1950s, as temperatures around the Northern Hemisphere reached early-twentieth-century peaks, global warming first found its way onto the public agenda. Concerns were expressed in both the scientific and popular press about rising sea levels, loss of habitat, and shifting agricultural zones. Amid the myriad mechanisms that could possibly account for climatic changes, several scientists, notably G. S. Callendar, Gilbert Plass, Hans Suess, and Roger Revelle, focused on possible links between anthropogenic CO2 emissions, the geochemical carbon cycle, and climate warming. By 1900, most of the chief theories of climate change had been proposed, if not yet fully explored: changes in solar output; changes in the Earth’s orbital geometry; changes in terrestrial geography, including the form and height of continents and the circulation of the oceans; and changes in atmospheric transparency and composition, in part due to human activities. Of course, there were many others. New climate theories were being proposed and new work was being done on heat budgets, spectroscopy, and the rising CO2 content of the atmosphere. Evidence for glaciation in low latitudes was explained by Wladimir Köppen and Alfred Wegener as the result of continents drifting northward under climate zones controlled mainly by latitude. Although this theory was not widely accepted by geologists, it is now seen as a first step in paleoclimatic reconstruction. In the 1930s, the Serbian astronomer and geophysicist Milutin Milanković, building on earlier work, outlined a comprehensive “astronomical theory of the ice ages” that viewed them as caused by periodic changes in the Earth’s orbital elements. Atmospheric heat budgets were constructed early in the twentieth century by William Henry Dines and George Clark Simpson, among others.

T. C. Chamberlin and the Geological Agency of the Atmosphere

The earth sciences may have experienced their most recent conceptual revolution in the 1970s with the acceptance of plate tectonics, but that was by no means their only major revolution. T. C. Chamberlin (1843–1928), America’s most eminent geologist turned geocosmologist, experienced three major conceptual revolutions in his field. As a student in the 1860s, he rejected the scriptural geology he had learned in his youth. As a working geologist interested in multiple glaciations, he rejected the dominant theories of hot planetary birth and secular cooling of the Earth as severely lacking in explanatory power. As one of the leading interdisciplinary scientists of his day, he formulated a new theory of the origin and evolution of the Earth and solar system—the planetesimal hypothesis. Glacial theories of the late nineteenth and early twentieth centuries appear in three distinct clusters: astronomical theories involve changes in the Sun’s luminosity, the passage of the Earth through opaque regions of space, and the variation of the Earth’s tilt and orbital elements; terrestrial theories include mountain building, volcanism, and changes in atmospheric and oceanic circulations; and molecular theories invoke changes in the water vapor or CO2 content of the atmosphere. The favorite among geologists was Charles Lyell’s theory of continental uplift and mountain building. James Croll’s theory of periodic changes in solar insolation due to changes in the Earth’s orbital elements was tantalizing but did not fit with geological evidence. Speculations about possible changes in the Sun were popular as well but were impossible to prove. Lord Kelvin had decided that the Sun was simply cooling off and the Earth’s future climate would be a cold, frozen one. Most theorists focused on a single mechanism of glaciation, with perhaps a secondary cause added in. There was some lip service to but little interest in multiple causation. Chamberlin tried to keep his options open by advocating his “method of multiple working hypotheses.” He was one of the first geologists to see the Ice Age as a series of multiple glaciations, and he was interested in searching for fundamental mechanisms of change that would explain the details, including the repeated oscillations between cold and warm epochs, the timing and duration of these events, and the differences between high and low latitude glaciation.