Essays - Spring 2005

A Long Cold View of History


How ice, worms, and dirt made us what we are today

By Donald Worster

March 1, 2005


The tsunami that killed more than 250,000 people living along the shores of the Indian Ocean also sent a shock wave through Western culture. Once again we learned that our vaunted technological civilization is vulnerable to the power of the natural world. Historians are scurrying to find examples from the past, when other such calamities destroyed lives, upset the political order, and challenged religious beliefs in divine providence. They point to the volcanic explosion of Krakatau in 1883 or the Lisbon earthquake of 1755 or dozens of El Niños. A new field of “disaster history” has sprung up, with the usual mix of serious scholars and publicity-seeking charlatans vying to say just how powerful nature has been as a force in history.

Nature afflicts us with sudden tragic events that kill or disrupt or impoverish, but far more of nature’s force comes to us with the slow, relentlessness of a glacier in motion or a continent in drift and over scales of time that far transcend our memories or written records, scales that can be revealed only by modern scientific methods. That power is not always destructive, although it is always indifferent. We would not number six billion people if nature had been against us, or if most of the planet’s forces had been hostile to life. Quite the contrary, Earth is wonderfully fit for life. Civilizations thrive on that fitness, although they seldom acknowledge just how much their success depends on natural resources: soil fertility, a generally stable atmospheric and climatic system, many organic allies, and the services that nature daily provides.

The hidden power of nature has not only affected primitive peoples— hunters and gatherers or peasant farmers—who lived in a close and fragile relationship with nature, but it has even shaped the growth and development of a great empire such as our own. America’s politicians, economists, business people, and academic humanists could all profit by taking a deeper look at the terms nature has set for North America, this huge bowl in which we live, stretching from Arctic tundra to green tropical mountains. What is this place and what has it allowed us to do? How did nature long ago determine our patterns of human settlement, economic development, and cultural evolution? How does nature still influence the way we live today?

Among other things, our continent has been shaped and influenced by the Ice Age, and much of what we have been allowed to do here reflects that fact. Yet the Ice Age, or the Pleistocene, has almost never figured in the written histories. Historians of the United States, for instance, write about the colonial period, the Civil War era, the New Deal, and the Square Deal but virtually never about the implications of the Ice Age for those periods of the nation’s history.

At least four times over the past million years, heavy snow has fallen, accumulated, and compacted into immense glaciers, and those sheets of ice have crept southward, crunching everything in their path. They have buried luxuriant forests that once grew within the Arctic Circle. They have scraped dark soil down to bedrock and pushed and piled it somewhere else. Repeatedly, they have driven to warmer climes any creature that could walk or fly. Naturalist and conservationist Peter Farb has described a glacier as a “monumental plow upon the land, scooping out depressions in the earth and grinding boulders down to pebbles.” American historians do talk now and then about plows, but those Ice Age plows exceeded anything we have ever invented. Glaciers are capable of moving hills and rivers, laying bare hundreds of thousands of square miles, remaking the face of a continent.

When the rate of glacial melt exceeded the rate of advance, the ice began to retreat, dropping its burden of earth and rock like a dirty blanket. The blanket was very thin in New England and several hundred feet thick in the Midwest. Mountains emerged from the ice, scarred and scraped clean. Geological formations such as eskers, hogbacks, and drumlins testified to the direction of glacial retreat. The largest depressions left behind became lakes, and the greatest of these became the Great Lakes, containing more fresh water than anyplace else on earth. Rivers flowed out of those lakes, seeking the ocean, and after each retreat the continent showed a new set of watery veins and arteries. Scattered around North America today, in the high mountains of Colorado, California, Alaska, and Canada, are a few remnants of the last ice sheet. But today only Greenland demonstrates the full massiveness of the ice when it was at its peak. Greenland is really Whiteland, buried under a sheet of ice two miles thick, just as much of the North American continent was once buried: Boston, New York, Toronto, Chicago, and Winnipeg all occupy sites once layered by thousands of feet of ice.

Surely that immensity of cold, hard whiteness, returning again and again, left a mark on subsequent human history, influencing later patterns of Canadian and American settlement and enterprise. But how might we make the legacy of the Pleistocene epoch more visible and convincing? One way is to play a game—to posit a different geological history for the continent and then ask what that difference might have made in the history we have lived and written about.

Imagine a map showing the continent’s landforms and vegetation patterns. Its key features are, of course, the eastward flowing Great Lakes and the St. Lawrence River, and the north-south-trending Rockies and Appalachians; deserts, basins, and coasts fill in the rest of the picture. Such a map usually just resides, inert and passive, in our minds, a terrain fixed in time, completely nonhistorical: the rivers never stop running, the mountains never wear away, the eternal coasts front unchanging seas. But we know that the physical map of the continent has always been in flux. North America has been undergoing profound change since its formation, though often the changes in the land are too complicated or subtle to be observed.

Put a date of 1534 on this mental map, the year the Breton sea captain Jacques Cartier sailed to the New World. Cartier, the first white man to penetrate the continental interior north of Mexico, provides our earliest written descriptions of the place—accounts filled with ambivalence (not surprising since his mission was to find a way to China). Cartier arrived at the rocky shore of Labrador in June and was disappointed to find “nothing but moss and stunted shrubs,” making him “inclined to regard this land as the one God gave to Cain,” fit only for outcasts and murderers. But he came back on a second voyage, which took him up the “great river of Hochelaga and chemyn de Canada” (later called the St. Lawrence), where he glimpsed a more promising continent of extraordinary resources and fertility. Somewhere to the west, he learned from the Indians, lay the Kingdom of Saguenay, a land that would make France as wealthy as Spain because it was as rich in minerals as Peru. But Cartier never saw that fabulous (and mythical) kingdom. He died in 1557 in his hometown of Saint-Malo on the English Channel, probably after much fruitless dreaming about that faraway place. His countrymen subsequently fell into religious wars that for a long time distracted them from thinking about the nature of the New World.

Run that map of 1534 backward in time, to, say, 20,000 years before the present (not so very long ago in geological terms), where we can see the
last great sheet of ice covering the northern latitudes of the continent—what scientists call the Late Wisconsinan glaciation. Although at first glance it seems like one solid sheet, it is made up of several discrete ice masses, the largest of which is the Laurentide Ice Sheet occupying the interior of Canada from Newfoundland to the Rockies and reaching as far south as present-day New York City and across to Illinois and Wisconsin. A separate Cordilleran Ice Sheet covers the mountainous areas of far western Canada. Most of Alaska is free of ice and has scanty but sufficient vegetation to support a population of mammoths, horses, bison, musk oxen, and caribou.

Now imagine that these glaciers do not melt away so quickly, that nature keeps them there until Captain Cartier arrives. What does he see? Ice and more ice. The land that God gave to Cain becomes more forbidding than ever. Indeed, no land at all is in sight along the Labrador coast, only a wall of frozen water, with icebergs calving into the sea. Cartier might just as well have gone to Antarctica. No Indian parties paddle out in canoes to meet him, offering to trade the beaver robes on their backs. That’s because there are no Indians or beavers in what we call eastern Canada. There is no St. Lawrence River draining the interior. In a sense there is no interior. Offshore, the natural environment is changed too. The Grand Banks, that famous shallow sea of upwelling currents that drew fishermen from England, France, and Portugal, has become dry land on our map. No codfish can swim there to attract fishermen. One such voyage would probably be enough for Cartier. He would sail straight home, never to return, and his fellow Europeans would remain indifferent to the New World, not merely for a few decades, but perhaps for centuries to come.

All of this remapping is not completely hypothetical. Such a glaciated place once really existed. Had that icy reality continued to exist just a little longer than it did, the effects of the New World on European civilization would have been profoundly different than they were (presuming, of course, that any kind of civilization could have emerged in a Europe likewise buried under an ice cap stretching as far south as Italy or Spain).

The New World discoveries, with all their ramifications for European science, literature, economics, political institutions, food, and demography, came at a time when nature cooperated wonderfully, opening up a continent for humans to explore, seize, and fight about. Put another way, the natural environment allowed European expansion, conquest, growth, and success. It also allowed the spread of European plants and animals, which environmental historian Alfred Crosby has called “the portmanteau biota,” those introduced species, from smallpox and dandelions to pigs and cattle, that ran wild across North America and helped the Europeans take control.

But if we venture further into the purely hypothetical, to imagine a continent that never existed, we can see how nature might have had a different impact on human history than it did. Bring that Laurentide Ice Sheet farther south on our mental map, for example beyond its true line of extent— bring it as far south as Georgia. We now have created a place where teeth-numbing melt water flows down both sides of the Appalachian Mountains. Now introduce Europeans into that imaginary scene and ask: What would they find and what would they do? What could they do in that colder, wetter environment?

They would find the eastern shoreline of North America extending far out into the Atlantic basin, because the amount of water in the ocean would be greatly diminished—taken up into the ice—and the continental shelf exposed. Coming ashore on that new raw edge of the continent, they would find tundra rather than a temperate land all around them. The broad Tidewater rivers would not look anything like the James or the Susquehanna, whose banks in colonial times were covered with hardwood forests festooned with wild grapevines and teeming with wild game. On the contrary, the scene would be bleak and cold, the growing season that of today’s Hudson Bay littoral.

What would that Virginia or North Carolina of a more extended Pleistocene allow them to do? Clearly, they could not expect to re-create in such a place of lichens and rock any kind of agriculture based on the major crops that have supported human civilization—wheat, oats, rice, maize, legumes, and millets. Importing the plantation system developed in Brazil to grow large-scale monocultures of sugar cane, tobacco, or cotton would also have been inconceivable. The most daring entrepreneur there would not dream of trying to farm plants requiring a long growing season, abundant rainfall, and temperate or subtropical weather. The plantation was invented in very warm latitudes in order to raise non-European crops for European consumption. The real South’s subtropical climate and soils provided the necessary conditions for such agriculture to flourish, but those conditions would not exist in our hypothetical Virginia of ice, tundra, and hairy mammoths.

If no plantation system were possible, then there would be no need for armies of field hands to cut and dry tobacco leaves or grind sugar cane into molasses. There would be no need of, or excuse for, indenturing poor Englishmen or for enslaving Africans and transporting them in chains. The natural environment of North America would not encourage such practices. We have no record of slave-based agriculture developing in a tundra landscape.

Slavery, to be sure, was an institution created by racial attitudes and an entrepreneurial economic culture, rather than by nature. Nevertheless, the natural environment of North America as Europeans found it in the late 16th and the early 17th centuries not only permitted and encouraged a slave-based plantation economy, it also allowed the spread of plantation agriculture from the Atlantic Tidewater westward to Texas. How can we understand that economy fully without taking into account the role of the environment? The plantation was at once a place of economic, social, and cultural relationships among different peoples and a response, by those with capital to invest, to the possibilities set by nature.

Canada, in contrast to the United States, did not present much agricultural potential. Shortly after the last ice sheet melted away, the first indisputable evidence of humans began to show up across Canada. Whether those archaic hunting peoples were newcomers to the continent or old-timers here for thousands of years is a separate debate. We do know for certain that as the ice melted they drifted eastward, skirting a 700-mile-long inland sea, Lake Agassiz, which at one time dominated the center of the continent. And we know that within a few thousand years after their arrival in eastern Canada they had learned to cultivate maize in the Ontario lowlands, where they found a lot of good soil.

Over much of Ontario, however, the retreating ice sheet left a land scoured of soil and bereft of fertility. A Precambrian basement rock, the Canadian Shield, now lay exposed in a vast semicircle bordering the Hudson Bay, like a medieval breastplate, stretching from the mountains of northern Labrador south to the Great Lakes and then across Manitoba all the way to the Arctic Archipelago. It covered almost half the present-day nation. A hard, knobby plate, it featured low hills a few hundred feet high and hollows filled with muskeg swamp, peat bog, and mosquito-rich lakes and ponds; a myriad of streams ran helter-skelter across the surface. Confronted by such an inhospitable environment, agriculture could not get much of a foothold; about all that would grow there were conifers and scattered hardwoods with shallow, spreading roots. Even overland travel was difficult. Long after the Europeans had arrived, the shield continued to impede land transportation and was open only to canoes and snowshoes. Although one day a railroad would eventually be dynamited through the rock and an industrial economy would grow up around mines, pulp mills, and hydro projects, agriculture would never be widely possible there.

The long-lasting effects of the Ice Age explain better than any other factor the contrasting fates of Canada and the United States. Here are twin-sister nations with similar cultural roots, virtually identical in physical size (each covering nearly 10 million square kilometers)—yet they are radically dissimilar in population size (the United States has almost 10 times the population of Canada), in national wealth (again, the U.S. annual gross domestic product is about 10 times Canada’s), and, following those material dissimilarities, in global power.

The thick blanket of till that the glaciers left south of the Great Lakes developed over several thousand years into fertile topsoil, the best and most extensive in the world. When Europeans first encountered that soil, it was covered with tall prairie grasses and oak and hickory forests. Think what a difference such an abundance of fertility has made in the fate of the United States. Settlers with plows, wagons, and dreams of acquiring private property tended to go south of the international border, avoiding the rock-hard center of Canada, seeking homesteads on the deep prairie soils of the American Midwest. A tinkerer named Cyrus McCormick followed their trails and set up a factory to make mechanical reapers for harvesting their abundant crops of wheat. Eventually New World maize flourished even better than wheat did and proved more profitable to raise, leading to the fabulously productive Corn Belt. Pigs were fattened on the maize, trotted to market, and sold as ham and bacon in the cities. Thus urban conglomerations grew out of the same soil as maize and livestock did—Cleveland, Chicago, Minneapolis, Milwaukee, Des Moines, Omaha, St. Louis, and Kansas City. So did industries for milling grain, packing meat, and assembling automobiles. Millions of immigrants went to the Midwest to work in those industries as well as to cultivate the earth. Whatever their line of work, they went because the soil was abundant there.

Creating the American Midwest took prodigious human labor and great amounts of capital, but neither the labor nor the capital created the topsoil that made the Midwest possible. That soil was the work not only of the glaciers but also of billions of organisms working in the glacial till: earthworms, mites, nematodes, fungi, bacteria, and badgers, all of them toiling tirelessly over thousands of years. Their significance to history is beyond easy reckoning. It is not too much to claim that the earthworm has been at least as important in the making of the U.S. Midwest as Cyrus McCormick, John Deere, Jane Addams, Frank Lloyd Wright, or even Abraham Lincoln. Somewhere on the streets of Omaha or Chicago there ought to be a monument to the lowly earthworm (especially the family Lumbricidae), who labored there long before humans arrived. How many worm workdays did it take to prepare the ground for civilization? How long can a civilization persist if it forgets its debt to this armless, legless, voiceless
“laboring class”?

The fate of nations depends on something more than political ideology or economic systems or human energy and ingenuity. It also depends on nature, starting with the awesome power of climate. We take climate for granted as a fixed entity, but it wobbles and changes as the earth wobbles on its axis. Climate is volatile and chaotic; as it shifts, so do the terms of existence for human societies. As these terms change, so do the images and mythologies that people use to explain who they are: the people of the long winters, the people of the desiccated plains, the people of Hurricane Alley. Even now, with all of modern technology at our disposal, we cannot evade the shaping power of climate and other planetary forces. The future of our civilization may lie at the mercy of advancing or receding ice sheets, a rising water line, a prolonged spell of drought, or a volcanic eruption.

But as the example of the Midwest-creating earthworm suggests, many nonhuman living organisms, micro and macro, have also had a vital role, over evolutionary scales of time, in creating complex ecosystems into which humans step and adjust or stumble and fail. Take away all of those big and little organisms, which together far exceed the human numbers on the continent, reduce North America to a flat, inorganic, sterile piece of rock or a sandy plain devoid of all living things, and then ask what the United States or Canada would be like today. Neither nation would be here. Nor would their predecessor nations—the Inuit, the Navajo, the Micmacs, and the Choctaws.

Popular and political culture sometimes recognizes the importance of those other-than-human organisms by celebrating them in stories, images, and icons. We have turned the white pine, the maple, the bison, the cod, and the beaver into symbols as much as we have turned them into wealth. They have even become markers of national identity, proudly displayed on our money, flags, and corporate logos. Shouldn’t their significance be acknowledged more often by historians?

But such acknowledgment should not merely reduce these organisms to cultural inscriptions in the history of ideas or popular iconography. They have been potent material agents in shaping our destiny. Modern science has revealed the extent and importance of the intricate biological interdependencies that have evolved in every habitat—the food and energy webs that link predator and prey, parasite and host, dominants and subordinates to form an ecological community. No organism, humans included, can survive without those complex communities of other living things. We should reconceive human history from this perspective, using the insights of ecology, geology, and other natural sciences to ask new questions about the past. We can no longer ignore the overwhelming scientific evidence of that principle of evolutionary interdependence.

The significance of the environment does not, of course, stop with the power that nature, organic and inorganic, holds over human life. As humans try to change their surroundings, the changes they make in the landscape become powerful material forces. To paraphrase Winston Churchill, we shape the landscape and then it shapes us. Among the most critical changes we make in nature are the depletions of vital natural resources we cause as we expand our habits of consumption. Substituting coal for wood, for example, or Herefords for bison or deer may overcome such depletions, but then the substitutions begin to forge their own chain of consequences. They force changes in technology, in the organization of labor, in gender relations, in the investment of capital, even in the discourse of philosophy.

Today, we are forging powerful new chains of environmental consequence by our often-unwitting behavior. The rock oil that we discovered in 19th-century Pennsylvania, for example, and then developed as a global oil industry, is now required to fuel 100 million automobiles in the United States and millions more overseas. Those automobiles are altering the global atmosphere, creating, according to the overwhelming majority of atmospheric scientists, a greenhouse effect that may make much of future North America hotter and drier than it has been for thousands of years. If that desiccation happens, or if Florida disappears through a melting of the polar icecaps, then environmental change will once again profoundly affect the history of civilization. This time it may be humans, not nature acting alone, that turn Manitoba into Nebraska and Nebraska into west Texas.

Historians have too often found such matters uninteresting, marginal, or irrelevant to their work. They have not been adequately trained to see the influence of the biophysical world. But to ignore the power and complexity of nature and place is to write history with one eye closed. We may see much with the open eye, but we will not see the past in its true breadth and depth.

Whatever their status or wealth, humans—from presidents and priests to homesteaders and housekeepers—have had to derive their living, directly or indirectly, from the land. They have, in other words, had to eat. Historians who look at the past with both eyes open will see that every generation of humans, our own included, has had to rely on soil, forests, and animals. They will see that when people fought they were often fighting over who could best exploit the land. The historian with vision will see that we cannot truly write the history of North America if the St. Lawrence River is left invisible, or if the adaptation of a farming society to the grasslands becomes untenable, or if the hard physical labor of climbing mountains to reach California is forgotten.

If historians ignore the power of nature—if they discount the Pleistocene, the force of climate, the interdependent web of life, the limits of natural resources—they will write bad history, history that is analytically incomplete and ungrounded. They will also add to our society’s irresponsible and thoughtless behavior. History ought to make us better equipped to deal with the world around us and to act as responsible citizens. But how can we do that if we are blind to the nature that feeds us, that conditions us, and that, even when not creating tsunamis and other awful consequences, imprints itself every day on our very existence?

Donald Worster is a visiting professor at Yale University. He is the author of two biographies of John Muir and John Wesley Powell, and he won a Bancroft Prize for his 1979 book, Dust Bowl: The Southern Plains in the 1930s.

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