ground1|
noun
1 the solid surface of the earth.
2 (grounds) the basis for belief, action, or argument.
—MERRIAM-WEBSTER’S COLLEGIATE DICTIONARY, ELEVENTH EDITION
Next to One World Trade Center, as part of the National September 11 Memorial, are the footprints where the two buildings stood, square depressions, water falling down the four sides and flowing into smaller squares. At ground level, the chest-high walls are etched with the names of those who died. Maybe most affecting are the names of the firefighters, those who rushed to help others, their names grouped together as they were in life. Next to the building footprints, a plaza holds some four hundred swamp white oaks and several rectangles of turfgrass. Small signs warn visitors off the grass, and when I ask a guard why, she replies, “It’s not a park; it’s a place to pay respects.” So I will follow a biblical lead. “Remove the sandals from your feet,” Moses is told before approaching the burning bush, “for the place on which you are standing is holy ground.” I take a seat away from the crowds, remove my shoes, and place my bare feet on the concrete. Sometimes in the northern forest, I’ll walk the loamy ground under Norway pines, salmon-colored needles cushioning my feet. But in day-to-day city and suburban life?
The experience of feeling our feet on natural ground, common throughout most of human history, has become increasingly rare. And for anyone in a city, rightly so—the hard and often filthy artificial surfaces beneath our feet call for some protection. The skin on the soles of our feet is our body’s thickest and some of its most sensitive, covering a high concentration of nerve endings. Our feet, in fact, are as sensitive as our hands—imagine wearing gloves as much as we have our feet in shoes. And the prints of our toes? As unique as our fingers—some militaries keep inked footprints as backup IDs—and the ridges and curves on the soles of our feet are as unique as those on the palms of our hands.
Around the world we have footprints preserved, in wet sidewalk concrete and clay Mother’s Day gifts, but ancient footprints, too. Most recently a 1.5-million-year-old set was found in northern Kenya, likely made by a human ancestor called Homo erectus. So similar to the prints of a modern human are the fossilized find that the archeologist who discovered them said they look “like something that you yourself could have made 20 minutes earlier in some kind of wet sediment just next to the site.” Wherever you are, a footprint offers an invitation to imagine those who walked here before you.
We are made for walking; our bodies evolved to perform this skill. And walking is maybe our most elemental experience of the earth, our most direct contact with the planet on which we rely. Walking (or bipedal locomotion, as it’s known in some scientific literature) propels us at the perfect speed to soak up our surroundings, to talk with a friend, to contemplate the impending decision between a slice of pizza or lunch of some other kind. If travel by airplane erases the history, diversity, and beauty of the land we fly over, and driving reduces the world’s sensory buffet to a tasteless, scentless, soundless blur, walking is where we have a chance to make it all up.
Maybe that’s why so many of us claim that our best thinking comes while walking. Charles Darwin had a “thinking path” outside his home, a circuit on which he knocked a small stone from a pile each time around. Virginia Woolf used walking to get out of her house and venture into an exhilarating evening where women weren’t often allowed, to “walk all over London; and see people and imagine their lives.” Thoreau thought walking four hours a day to be living well, and wrote an essay in which he extolled the virtues of sauntering, to which the secret of success was “having no particular home, but [being] equally at home everywhere.” William Wordsworth is said to have walked some 180,000 miles in his lifetime, which averages to more than six miles a day beginning at age five. There are countless famous examples of how walking stirs the soul and makes us who we are.
These days, though, we don’t walk much. In fact, we in the United States walk less than the inhabitants of any other industrialized country. That my immediate examples above all hail from the nineteenth century makes sense, as even the “civilized” world was still made for walking then, not yet rearranged for cars, trucks, and buses. To mourn the loss of walking isn’t merely to pine for the good old days, but to call attention to something we have always enjoyed. In New York, Paris, and other walking-friendly cities, we humans take advantage; we walk. I think we understand, as Rebecca Solnit explains in Wanderlust, that with the loss of walking we lose “an ancient and profound relationship with the body, world, and imagination.”
We are learning more all the time about the true costs of this loss. As one Slate writer says, “The decline of walking has become a full-blown public health nightmare.” One new study after another confirms that walking promotes health and well-being. This is true whether said studies claim that walking will bring “substantial reduction in the incidence of cardiovascular events,” or that in terms of improving health, walking is “the equivalent of popping a series of magic pills.” In addition to cutting our risk of becoming diabetic, suffering a stroke, or developing cancer, walking reduces hypertension, helps prevent depression, and strengthens the circulatory system. While Amish men take about eighteen thousand steps per day and Amish women fourteen thousand, the average American takes four thousand. Perhaps as a result, only 4 percent of Amish are obese, compared with 30 percent of the general population. Declares the nation’s leading newspaper, “To Age Well, Walk.”
At the southern end of Manhattan the streets still generally follow the more natural routes adopted by the Dutch from the Indians and developed in a way that reflected the island’s hilly topography (the native Lenape name translates as “island of many hills”) and swampy ground. Though it runs only as far north as Wall Street (once an actual wall built to keep the English or Indians out), the street map of the Dutch city (New Amsterdam until 1664) remains largely intact. Beyond that boundary lay wilderness. Here, across Houston, I find a very small park, just twenty-five by forty feet, that Time Landscape created in 1978 to preserve (or, actually, to re-create) the forest that “once blanketed Manhattan island.” The surrounding area, says the sign, was “once a marshland dotted with sandy hills,” the “trout-filled Minetta Brook” making it a popular site for fishing and hunting ducks. I stand outside the park’s short fence on flat, smooth, hard concrete. On the other side is dark soil holding living things. Once there was a woodland here of witch hazel, black cherry, and red cedar trunks. Oak, sassafras, sweetgum, and tulip trees, arrowwood and dogwood shrubs, bindweed and catbrier vines, and violets. The small park invites city dwellers “including insects, birds, people, and other animals” to experience “a bygone Manhattan.”
Farther up the island, north on Fifth Avenue, the Empire State Building marks the horizon ahead, while behind me One World Trade Center marks the other. At Fourteenth Street I stop, for here begins a most remarkable story about the ground beneath this city.
In 1808, in an attempt to unravel the “evil of confused streets” and to facilitate the development of the island, city commissioners commissioned what would eventually become the street grid of horizontal and vertical lines that defines today’s New York City. In doing so they turned to John Randel Jr., first for the grid’s design—a survey that took two years to complete—and then for its execution. Turns out the survey was the easy part. To execute the plan, Randel had to mark the grid exactly (and this was a man of precision, in one case complaining that his measurements had set the grid off by 1.8 inches). For six years, the work took him through swamps and woods, farms and fields, over more than eleven thousand acres in total. He was pelted by landowners throwing artichokes and cabbages, chased off property by dogs, and arrested several times. Nonetheless, Randel and his employees placed more than a thousand bolts and monuments to mark future intersections. The development that would follow Randel’s work took more than a hundred years to realize, but began almost immediately. Swamps were drained, woods were cleared, farmland and fields paved, the hilly island leveled—the bedrock just beneath the surface blown apart.
In fact, this drastic rearranging of surface life drew—even two hundred years ago—criticism for its brutish disregard of the island’s natural topography. Walt Whitman and Frederick Law Olmsted criticized the plan, as did Alexis de Tocqueville, who claimed that it represented the imposition of “relentless monotony.” Others criticized the chopping down of forests, burying of streams, and filling in of hollows to create a flat surface on which the commissioners could more easily lay out their grid. “The great principle which governs these plans,” wrote one critic, “is to reduce the surface of the earth as nearly as possible to dead level.” This is the reason Manhattan’s streets are so flat and straight, its long rows of tall buildings creating canyons of stone that echo the sound of traffic, why twice a year the sun sets perfectly aligned along east-west streets, an event that’s come to be called Manhattanhenge. Some ancient people’s monuments to honor the sky and its gods? Or simply the unintentional result of what another contemporary critic called the “republican predilection for control and balance… (and) distrust of nature.”
Though Randel and his men tromped through swamps, climbed hills, and crossed streams, almost none of those natural features figured in their final maps. In fact, even in their field notes the natural world was valuable only as a resource for human use. I think of historian Frederick W. Turner’s description of European explorers discovering a New World filled with flowers and sea life and birds, a beauty worthy of inspiring song and poetry and praise—even “a new mythology”—and then his devastating line: “As it was, they took inventory.”
Randel’s maps take inventory as well, of ground that is portrayed as ready for the city’s taking. In this way, Randel’s hand-drawn and colored maps—which when connected together to show the entire island stretch nine feet long—reveal the challenge posed by maps in general, that they are abstractions of reality reflecting certain sets of values. It may be obvious that no map can include every tree or bee or birdsong, but the implications may not be so. While on our maps we often see a park as a block of green, for example, or a lake as a blob of blue, more often a field of wildflowers or a stretch of woods is simply left blank. Even today our road maps—think Google—show only blocks of color dissected by streets. These are maps of abstraction, of time schedules telling us when we will arrive, not maps of living things. Whether we use them to understand the route through a city or to make decisions about what to “develop” and why, we would do well to pause. “Caution,” a corner of each map might read: “No map can hold the true richness of the world.”
Given that the Earth is spinning in space as it spins around the sun, and the sun is spinning in a galaxy that itself is hurtling outward at a thousand kilometers per second, I sometimes wonder how we are able to walk this ground at all. But as with so much else on this close-to-perfect world, it turns out that our planet spins at just the right speed to keep us happily walking crowded sidewalks, pizza in hand. The concept is this: as in a subway car or an airplane in flight, we seem set in place—we can walk around, stand on one leg, perform daring feats of balance—even though the train or plane is rushing us from one locale to another. It’s only when that vehicle begins to slow or accelerate that we feel the pull—our body no longer quite sharing the vehicle’s speed. All the spinning through space of celestial bodies doesn’t affect us here on Earth because all these various bodies are moving at a constant rate.
There’s also the fact of gravity. Newton gave us a basic understanding, which Einstein then complicated. Early in the twenty-first century, gravity is still acknowledged as “the most puzzling and least understood of the four fundamental forces of nature.” Any simple definition of the word hides the fact that scientists still have loads of questions. “A force pulling together all matter,” says one definition; another reveals that gravity not only dictates the movement of the planets in orbit around the sun and the movement of our oceans’ tides, but also “the adherence of humans to Earth.” And that’s not all. Besides bringing such benefits as holding our atmosphere in place, gravity actually shapes our bodies. To put it another way, we are physically shaped—our bones and muscles molded—by our body’s resistance to gravity’s constant pull.
The mysteries of gravity relate to us in other ways too. After spending 340 days in space, American astronaut Scott Kelly admitted that the hardest challenge wasn’t the effect of weightlessness on his body but “being isolated from people on the ground who are important to you.” That pull toward our loved ones is a feeling we all can understand. And there’s more: Kelly also felt a pull to the planet (“The solid earth!”) on which we all rely. After witnessing great spreads of pollution, storms the size of which we have never seen, and the fragility of the atmosphere, he said, “I feel more like an environmentalist since I’ve been up here.” Like the size of the universe or time before your time, gravity, a force we only begin to understand though it shapes Earth’s life, seems a mystery too big to hold, and to which the only worthy response is astonishment and thanks.
Walking past Rockefeller Center I think of the annual Christmas tree in the square, sawed at its base and delivered by semi, set atop a sea of concrete. Everywhere in this city you will find that juxtaposition of the natural world with the human-made: the rooftop garden, the small pine on a patio thirty floors up, the overgrown rail line turned park. It’s a juxtaposition dramatically displayed on the cover of Eric Sanderson’s book Mannahatta—an aerial photograph of Manhattan taken from the southern tip, the right half of the island as it looks today, with its ground hidden by skyscrapers, and the left half made to look as it did in 1609, when Henry Hudson arrived, the ground hidden by trees, bursting green. It’s this image that originally led me to contact Sanderson and ask whether we could meet, this side-by-side view of past and present. What I hadn’t realized was that for Sanderson the image speaks of the future, of what could be—of what will have to be, if we are to thrive.
Wearing a white beard and a red stocking cap, Sanderson laughs as we meet, extending his hand. He’d brought along a copy of his book but left it on the subway. “So Mannahatta is riding around below us right now,” he says. That which is below us has always fascinated him, including Umpire Rock, the outcropping on which we stand. “I feel like this rock is the symbolic heart of Manhattan,” he says. It’s remarkable rock, Manhattan schist, formed 450 million years ago, incredibly strong, gray, flecked with sparkling mica, its close-to-the-surface presence supporting the clusters of skyscrapers in Downtown and Midtown, and today the perfect hard sliding slope for wobbly little kids in neon down jackets.
“One of the things I like to do is to walk around in Manhattan,” Sanderson says. “Where there are excavations for new buildings, I like to look in the hole, see what’s down under the ground.” It’s ground, he explains, that is remarkably diverse, with some eighty-seven different kinds of soil within the city limits. “I see other people doing the same thing. I think there’s huge fascination about what’s underneath the surface, particularly in heavily developed places like Manhattan. I have a friend here in the Bronx who said when he was nine he was walking with his mom somewhere, and they saw a road crew working on the street. They’d dug down into the street, and he could see the concrete of the sidewalk, then the bricks underneath that had been there before, and then the soil. He said until that moment, he’d thought maybe it was just concrete to the center of the Earth.”
Reminding us of the world beneath—and beyond—our pavement forms a critical part of Sanderson’s work. Of his employer, the Wildlife Conservation Society, he says, “That’s our goal, to connect the city and the wildlife.” For a man whose work places him at the forefront of what can be a very discouraging fight to save wildlife and wild places, Sanderson is remarkably optimistic about being able to make that connection. “My feeling is that nobody really wants to destroy the environment. They just feel like they’re forced into these decisions that they know are not so great.”
Sanderson sees a desire for other options as reason for hope, reason for trying to figure out “how to talk to city people about wildlife and nature and wild places.” People want to do the right thing, he believes, they just need to know they can make a difference. “There’s that old quote about how you need to know something in order to appreciate it in order to love it and take care of it,” he says. His wonderful book about the world under our feet was a major attempt to facilitate that process. “When I first moved to New York I was really struck how New Yorkers love the great details of their block. Mannahatta is a way to tell them something brand-new about the place they lived that they never even guessed, and in huge detail.”
And how to share that detail? In a word, maps.
Sanderson has been able to show New Yorkers—and all of us—something new about the place where so many of us live. By creating maps of the past and present, he offers us an understanding upon which to build our lives. “Can we travel back in time to see Mannahatta as it was?” he asks in his book’s early pages. “And will that view change how we see our world today?”
Key to his mission are two complementary maps called The Human Footprint and The Last of the Wild, both of which visualize the human impact on the ground. Using data detailing population density, land use, roads, and artificial lights, Sanderson and his team of colleagues were able to show that at the end of the twentieth century, humans “directly influenced” 83 percent of Earth’s land surface. The quotation marks are important, for if we factor in indirect influence like climate change and chemical pollution, that number reaches 100 percent. We have been—we are—nearly everywhere.
Critically, we take for ourselves huge portions of Earth’s resources—a trend that threatens to increase as populations around the world move toward consuming at current developed-world levels. This spreading ourselves everywhere has meant devastation for our fellow creatures. In its most recent “Living Planet Report,” the World Wildlife Fund declared that wildlife populations around the world have fallen by nearly 60 percent since 1970. This includes populations of mammals, birds, fish, amphibians, and reptiles, impacted by an ever-increasing human population that is clearing land to plant crops and expand cities. Making the situation even more dramatic is how rapidly these changes are happening. “Wildlife is disappearing within our lifetimes,” said the group’s director general, “at an unprecedented rate.”
But this consumption of Earth appears to have serious implications for our own species as well. For example, Sanderson’s team found that humans already influence fully 98 percent of the places where it’s possible for us to grow rice, corn, or wheat—in other words, we already impact pretty much all the land on which we can grow food. This matters because by 2050 we will have three billion more people to feed. In fact, some estimates indicate that satisfying midcentury human demand will require the equivalent of four current planet Earths. Sanderson’s maps are stark reminders that we have no new land to discover.
Especially for Americans, this can come as a shock. We have long based our culture on consuming what we know, then moving to new places. “I think that’s an American conundrum,” Sanderson says. “We haven’t really spent a lot of time thinking about what we’re giving to the future in terms of resources. We’re very proud of this technology we’ve created and of the science that we’ve done. But we’ve been so wasteful of resources for so long.”
At the same time, Sanderson’s maps also show that the ground feels our influence on a gradient—in some places, such as cities, our footprint is heavy, while in other places it’s relatively light. In fact, on 17 percent of Earth’s land surface, that footprint is light enough that we might still call those places “wild.”
Sanderson and I decide to walk to Times Square. Crossing over Fifty-Sixth Street on Sixth Avenue, he tells me that we have just walked up what was once a little hill. Looking back, I see the faint slope. But standing at this intersection once marked by Randel, that is the only sign of nature, this slight paved rise. “If we had the Mannahatta map we could tell we just walked across three ecosystems, three ecological communities,” Sanderson tells me. We continue our walk down Sixth Avenue through the towering buildings. “It’s not unlike the Grand Canyon,” he says of the city. “It took a long time to build, you don’t really know how it happened, it’s huge!” Finally we reach Times Square. Walled in by buildings and bright flashing signs, we see no trees, no birds, no natural ground. It is, he says, “a temple of consumerism.” And it’s hard to imagine that nature was ever here.
Hard for me, maybe, but not for him. “There was a pond here, and streams that fed down what’s now Sixth Avenue. People used to fish for brook trout here. It was famous for duck hunting in colonial times. This was a long way to come, three or four miles through wooded hills.”
Once a wilderness north of town, this ground is now asphalt and concrete. Our footprint continues even under the surface, where below us run the arteries that keep this city pumping—power, cable, water, steam, and gas lines crowd the underground. And below those, tubes to carry the subway, and the sewage, and deep water lines, the deepest pipes reaching down eight hundred feet. No sign of soil, of green life emerging from dark underground. And no evidence that we are connected to that life. The illusion that we could exist without nature is complete.
Remarkably, the day I visit, one digital billboard advertises not a product but a project by the renowned architect Maya Lin, world famous for her design of the Vietnam Veterans Memorial. The ad celebrates Lin’s “last memorial,” called What Is Missing?, an interactive website featuring videos, audio, photos, and text that together present an elegy for lost and threatened species. As she says, “I am going to try to wake you up to things that are missing that you are not even aware are disappearing.”
What is missing here in Times Square is almost everything. I remember when I first visited Manhattan some fifteen years ago I was shocked—coming from New Mexico—at the lack of natural life. I felt hemmed in and cut off; I wondered how people here survived. But since then, I’ve had more time here, enjoyed its parks, learned about the 250 species of birds that migrate through, and seen New Yorkers thrill to the wanderings of an adventurous coyote, to an eagle’s unannounced stay, events that make front-page news. I have come to understand what Sanderson means when he talks about conservation—that it’s not only about preserving those wild areas his maps identify, nature for nature’s sake. “If conservation is also about conserving the human relationship to nature,” he explains, “then this is the most important place.”
The crucial question for conservation may be, Where to from here? It’s a question that has special relevance for anyone living in a city, which means a large—and growing—percentage of humanity. Many of us will soon be living in megacities of ten million or more—already there are more than thirty, and by 2050 there will be some seventy-five—and many of these cities will be linked together into megaregions of continuous development. Sanderson is no Pollyanna, and he’s realistic about what this means for the wild world. Human population growth, food production, land-use change, biodiversity loss—the impacts Sanderson included in the human footprint map—are going to grow more intense. Our human footprint is going to grow larger, and we are going to push the life of this planet harder than ever before.
Sanderson gazes at the throngs of shoppers and tourists, flashing lights and signs. “If we imagine nature after 2050—which isn’t that far away—when seventy or eighty percent of the world’s population lives in cities and the world population has leveled off at nine billion or ten billion people, what is that world going to look like for nature, and for people too?”
A fascinating question. And I know a city that might already offer an answer.