DOWN TO EARTH
PROLOGUE
ROCKS AND HISTORY
Open a U.S. history textbook and glued inside the cover is the familiar map of the nation, as if the place were simply a given. But land is a much less settled issue than those maps suggest. While historians have spent a great deal of time examining how various immigrant groups came to America, they have spent almost no time considering how America itself—the land—came to be where it is on the globe. In this sense, our nation’s history began not in 1607 with Jamestown, in 1492 with Columbus, or even thousands of years before then whenever the first Paleoindians came here. Rather, American history got underway some 180 million years ago when the earth’s only continent, a huge landmass known as Pangaea, began to break apart.
At first, Pangaea split into two parts. Then as the Atlantic Ocean expanded, North America separated from Africa and later from South America. Slowly, the continents began to take their present positions on the globe. By about 60 million years ago, North America—a discrete and contiguous landmass—had been born.
From this one momentous geological occurrence, a host of profound consequences followed. Separated from the so-called Old World of Eurasia, life forms in North and South America developed in isolation, explaining why Europeans who ventured to the New World for the first time were so struck, at times even horrified, by the continent’s strange new plants and animals, especially its bison, moose, cougars, alligators, and rattlesnakes. Continental drift also explains why the Americas, severed from Eurasia by water, were the last of the habitable continents settled by humankind. When the Paleoindians did reach these places, they lived in isolation from Europeans and their diseases, a fact that had a stunning impact in post-Columbian times. Indeed, without the breakup of Pangaea, the entire rationale for Columbus’s voyage simply would not have existed. Fourteen ninety-two would be a year of no particular importance, the Columbus national holiday just another ordinary autumn day.
Nowhere is it written that U.S. history must begin with the breakup of Pangaea. Beginnings are in themselves quite arbitrary. One could just as easily start the story with the emergence of life four billion years ago or even the development of the earth itself 500 million years before that. But beginnings do tell us a great deal about an author’s underlying assumptions about the past. When textbook writers open their narrative of the American republic with Columbus or, more commonly today, with Paleoindians trekking across the Bering Strait, they put forth a very anthropocentric view of the past. History begins when people come onto the scene. But by dwelling, as most U.S. historians do, on such a relatively short expanse of time—1492 or even 12,000 B.C. to the present—it is easy to lose sight of the powerful natural forces that have played such a formative part in the history of this country. It becomes easy to forget that the earth’s climate, geology, and ecology are not simply a backdrop, but an active, shaping force in the historical process.
History is structured by a vast array of natural factors: geological forces that determine if minerals will be available for mining, if the soil will be fertile enough for planting crops, and if ample water and level land exist to grow those crops with a minimum of effort; ecological forces that determine the range and diversity of plant and animal life, if corn or wheat, cows or llamas, will be available for domestication, and if there will be adequate forests to supply timber; and climatic forces that determine if enough frost-free days will be present for an ample harvest. Such natural factors—largely beyond the control of human beings—have had enormous impact on how the past has unfolded. People make history, but under circumstances that are not of their own choosing, Karl Marx once observed. He had economic forces in mind. But his statement applies as well to the world of nature, to the far-reaching climatic, biological, and geological processes that have determined the possibilities open to human beings on this planet.
Thus America’s place on the globe, while often glossed over and forgotten, needs to be taken seriously. The land area of the United States is uniquely positioned to capture a relatively large amount of solar energy—the key ingredient for transforming inorganic matter and water into food through the process known as photosynthesis. Food crops such as wheat, corn, soybeans, and oranges, among others, flourish in the nation’s temperate climate, rich soils, and abundant sunlight, explaining why California and the central part of the nation are in the front ranks of world food production.1 Imagine for a moment how severely curtailed the food supply would be were the present continental United States rolled on its side. Such a move would make the nation’s north-south dimension three times the distance from east to west, instead of the other way around. Spanning many more degrees of latitude and with much of its landmass now lying outside the temperate zone, America would be far less suitable for agriculture.
MAP OF NORTH AMERICA
Adapted from Out of Many, vol. 2, Brief 3rd ed., A History of the American People, by Faragher, Buhle, Czitron, and Armitage, © 2001, by permission of Pearson Education, Inc., Upper Saddle River, NJ.
Continental drift is hardly the only geological episode to have far-reaching consequences on American history. Consider the birth of the Rocky Mountains and its effect on the biogeography of the world’s breadbasket, the Great Plains. Before the creation of the mountains, a process geologists refer to as the Laramide Orogeny, beginning some 80 million years ago, the Great Plains were a tremendous inland sea. The emergence of the Rockies, however, plugged the water’s entry from the Pacific and Arctic oceans, creating conditions favorable to the eventual emergence of forest cover on the plains. The mountains also dried out the land by capturing the moisture of clouds on their windward side, creating a huge rain shadow that left the leeward plains in an even more arid state, precisely an environment suitable for the growth of grass. Meanwhile, the rain that did fall in the mountains washed away sediments and deposited them further east with each passing year, covering the old seabed with a layer of loose silt that was hundreds of feet thick and producing in the process one of the most level stretches of land on earth. The Rockies, by drying out the landscape of the plains, forced plant life to adapt accordingly. Grasses, which have complicated root systems that can exploit even the smallest amount of moisture, flourish in such an environment. Into these grasslands the American pioneer eventually forged, prepared to break the sod and replace it with another grass: the wheat so fabulously adapted to life in an arid locale.
That was not all the Laramide mountain-building episode did to contribute to America’s rise to world economic dominance. It also broke up granite and metamorphic rocks, allowing metallic minerals to insinuate themselves into the faults left behind. Minerals such as gold, silver, zinc, lead, and copper settled that much nearer the earth’s surface, where they could be mined with relative ease. Without this geological episode there would have been no Colorado gold rush in the 1850s, no mineral belt running through the state. The Laramide revolution was but one geological event on the nation’s road to wealth. Taken together, the combined effect of the region’s geological history accounts for North America’s near total self-sufficiency in minerals. As one geologist has exclaimed, “No other continent has it so good!”2
One other event from the distant past is also worth our attention: the Pleistocene epoch that began 1.6 million years ago, the period commonly referred to as the Ice Age. During this time, huge glaciers, as much as one to two miles thick, covered the northern reaches of the continent (as well as Europe and Asia). Tundra stretched out over what is now Manhattan. The ice expanded south and then retreated on some 18 to 20 different occasions over the Pleistocene. The switch between these glacial and interglacial periods is not completely understood, but many attribute the shifts to changes in the Milankovitch cycle, named after the Yugoslav geophysicist who discovered this phenomenon back in the 1920s. From time to time, he observed, the earth’s orbit around the sun changes, sometimes placing the planet closer to the star, where it can receive more heat, and sometimes further away,
making the climate colder and producing a glaciation. Beginning about 10,000 years ago, the climate shifted and the ice sheet that covered much of Canada and the northern United States withdrew. It is no coincidence that American history has taken place during an interglacial period. Indeed, it is difficult to imagine the course U.S. history might have taken—or whether there would even be a United States—had the earth’s orbit not changed and the ice not retreated. It is also sobering to note that although there is much concern today with global warming, in the long run it may be cold—that is, the return of another ice age—that will turn out to be our true nemesis.
Like the effects of continental drift and mountain building, glaciation too has had tremendous consequences for life on this continent. Animals and plants have adapted themselves to the glacial conditions that have prevailed for 90 percent of the last few million years. And again, U.S. agriculture seems to have benefited greatly from yet another geological event. When the glaciers retreated on several occasions from the Great Plains, they left behind a fine soil deposit called loess. The loess was eventually driven east by the prevailing westerly winds, finding its way to Kansas, Nebraska, Iowa, Wisconsin, and Indiana and providing the basis for rich, fertile soil—in some places 20 feet thick. Likewise, the soils of eastern Canada were scraped up and, in a generous moment, dumped by the glacier in the Midwest, again bolstering the fertility of our farms. It was not for nothing that the nineteenth-century geologist Louis Agassiz dubbed the glaciers “God’s great plough.”3
Without these soils, without the requisite sunlight and the right climate, America would no longer be the world’s breadbasket. John Deere and his “singing plow,” Cyrus McCormick and his famed reaper would become obscure tinkerers with projects of little practical importance, instead of icons discussed in virtually every American history textbook. Such are the implications of the really long view of the past. Suddenly the earth itself becomes an actor, a force to be reckoned with, instead of a simple line drawing inside a book’s cover.
PART ONE
CHAOS TO SIMPLICITY
1
WILDERNESS UNDER FIRE
Although Christopher Columbus has a national holiday to honor his 1492 mission, on the basis of sheer exploratory drama we ought to celebrate something called Clovis Day instead.1
At least according to a much-honored archeological theory, the Clovis people trekked out of Siberia sometime before 11,000 years ago. Crossing the Bering land bridge (although “bridge” hardly does justice to the plain that purportedly stretched nearly 1,000 miles in width), they forged their way into Alaska, marking the first human settlement of North America. Within less than a millennium, they traveled the length of the continents, venturing to the Great Plains and the American Southwest (where their stone points were first discovered in Clovis, New Mexico), eventually ending up at the tip of South America. Two formerly uninhabited continents were quite suddenly—in geologic time at least—brought into the orbit of Homo sapiens. As discoveries go, this was a monumental journey that marked the greatest expansion across a landmass in the history of humankind. It can never be repeated on this planet.
That is, if it happened at all. In recent years, new evidence suggests the possibility that human beings arrived in North and South America earlier, perhaps as much as thousands to tens of thousands of years before the first Clovis hunters or Paleoindians crossed the Bering bridge. Using the technique of radiocarbon dating, archeologists have uncovered a site in southern Chile that goes back nearly 15,000 years. Even a human footprint exists to confirm the presence of these pre-Clovis people.2
Did these early settlers, whenever they arrived, walk lightly on the earth, extracting a living ever so gently from nature, leaving behind a pristine wilderness, as some environmentalists like to think? The notion that Indians acted out the ideals of the modern-day conservation movement has a long and enduring history. But such a view, however popular, has little basis in reality. Compared to the excesses of twentieth-century consumer culture, Native American life may well seem ecologically benign. But we must be careful not to romanticize the people and landscape in the period before European contact. Indians were intimately aware of and connected to the environment around them, and the rituals they took part in often emphasized their recognition of that dependence. They farmed the soil, hunted game, set fires, and gathered berries and nuts, engaging in a spiritually rich relationship with the land, while shaping it to meet the needs of everyday survival. Sparsely settled the land may have been, but a total wilderness it was not.
CRYING INDIAN
This advertisement, an American icon in the 1970s, helped popularize the idea of Indians as conservationists. (Keep America Beautiful, Inc.)
OVERKILL
When the Paleoindians arrived on the Great Plains, they found it teeming with large mammals, so-called megafauna, that included mammoths weighing between eight and nine tons (50 percent more than an African elephant), three-ton ground sloths, beavers the size of bears, 500-pound tapirs, plus exotic creatures like the pampatheres, akin to an armadillo but with the stature of a rhinoceros. Camels, saber-toothed cats, cheetahs, lions, antelopes, and horses all roamed the American West, and all were driven to extinction sometime before 10,000 years ago, near the end of the Pleistocene epoch.
Most of the available scientific evidence points to changes in global climatic conditions as the cause. Temperatures increased dramatically and the climate became more arid near the end of the Pleistocene. Even worse from the standpoint of living organisms was the onset of large swings in seasonal temperatures that resulted in much colder winters and hotter summers. Plant and insect communities sensitive to such shifts confronted a new and far less hospitable physical reality. The creation, in turn, of radically different habitats, goes the theory, had dire consequences for the megafauna as the animals found less food to eat. It is even possible that the growth of new toxic species of grass poisoned the mastodons and other large creatures.3
Not all scientists agree that climate played the pivotal role in the mass extinctions. Some researchers hold the Paleoindians themselves to blame, killing a mammoth one day, a ground sloth the next, as they expanded south down through the continents. Waging the equivalent of prehistoric “blitzkrieg,” they argue, the Paleoindians exterminated animals unprepared to deal with being attacked by human beings. In this view, the continent’s first settlers were hardly the low-impact stewards over the land that they are often made out to be. Nevertheless, over the course of the last 10 million years North America has experienced no fewer than six other such episodes of extinction, and in none of these events was humankind the culprit. That leaves the changing climate as a likely suspect.4
More important than precisely what caused the extinctions is the legacy left by this catastrophic annihilation. It is not too much to say that the Pleistocene extinctions altered the course of modern history, depriving America of valuable animal capital. Although the exact number of species exterminated remains unclear, unquestionably the vast bulk of North America’s large mammals disappeared in the event. That left the continent in a state of biological impoverishment. It is no accident that of the 14 species of big domesticated animals relied on by cultures around the world for food, clothing, and transportation (the cow, pig, horse, sheep, and goat being the most important), only one, the llama, was domesticated in the Americas. The remaining 13 all came from Eurasia. The New World originally had a single species of horse, and unfortunately it was exterminated during the Pleistocene. History might indeed have unfolded differently if the European explorers of the sixteenth century had ventured to the Americas and found themselves face-to-face with a mounted cavalry.5
HIGH AND LOW COUNTERS
Although a great deal of ink has been spilled on the subject, we still have only a vague idea of North America’s Indian population at the time of European contact. The native peoples themselves kept no records detailing their numbers, and with no direct demographic evidence available, researcher
s have had to devise various methods for estimating the continent-wide population from European observations recorded in diaries and other written sources. Early estimates done in the mid-nineteenth century—one by artist George Catlin, the other by missionary Emmanuel Domenech—concluded that the aboriginal population was roughly 16 to 17 million at the time of European arrival. When bona fide researchers got out their pencils and pads, however, the numbers plummeted. In 1928, the disciples of ethnologist James Mooney, the first scholar to study the problem, put forth a figure that was only slightly over a million. How did Mooney and his colleagues arrive at such a small number? Employing what some have labeled a “bottom-up” approach, Mooney calculated a total population for each tribe in North America, relying on historical evidence provided by European missionaries and soldiers. Only he chose to lower the figures given by these white observers. He reasoned that soldiers may have felt compelled to overestimate a given native population, and thereby enhance the magnitude of their own accomplishments. Victory over 10,000 Indians certainly looked better on paper than a triumph over half as many. After discounting the historical record, Mooney then simply added the numbers of the various tribes together. His million-person estimate endured for several decades and is still sometimes cited by conservative pundits eager to show that North America was largely virgin land populated by small bands of hunters before the Europeans arrived on the scene to pave the way for culture and civilization. Today, however, most researchers reject this extremely low number.6
Down to Earth_Nature's Role in American History Page 2