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introduction

An Update for the Age of Global Warming

Bill Green

WHEN I BEGAN THIS BOOK in the late 1980s, Antarctica, and certainly the McMurdo Dry Valleys, lay on the periphery of modern consciousness. My interest in writing it grew from a personal need to show something of the “human face of science” and to provide an account—all too rare in our literature—of how it felt to do field research in the hostile, austere, but beautiful environment of the Antarctic continent. I had attempted to summarize these motives earlier, in a journal entry for The Sciences that read: “Science, sometime in the past, had decided not to deal with certain aspects of reality. The scientist worked with and described the world as abstraction and left the prickly pear of direct experience to the poet and the painter. It was, perhaps, a happy division of labor, but at times it seemed stifling to me. In the midst of a sentence that read, ‘Water samples were collected with a 6.2 liter Kemmerer bottle attached to a nylon line,’ I wanted to say something about the afternoon shadows on the mountains or the murmuring of a distant stream or the way the wind was sapping my strength. I wanted to say something about the way water tastes on an Antarctic lake after a ten-hour day. These things hovered like ghosts around the edges of scientific prose. They formed the private face of science—the human face.” In a way, this statement became the template on which the book was written.

In recent years, in the aftermath of important oceanographic and especially atmospheric studies, Antarctica has emerged as a continent central to our understanding of the Earth as a global system. Its ice caps, and the tiny bubbles within them, have recorded traces of ancient air and have provided clues to past climates. Its stratosphere, and the processes unfolding there, have been probed by balloons and spy-planes and satellites and the data have unequivocally signaled the impact of synthetic chlorofluorocarbons (CFCs) on the Earth’s precious ozone shield. The lower atmosphere, above South Pole Station, has provided evidence for the far-flung impact of industrialization and deforestation on the tenuous thread of air—the troposphere—on which all life depends. And the continent’s rocks, exposed in only the smallest of deglaciated regions, have been a window onto a deep and warmer past when Antarctica lay in more northerly latitudes.

But, perhaps, most importantly, Antarctica has come to be seen as a key to global climate. We know from studies around the world that mountain glaciers are everywhere receding, whether in the Swiss Alps or on the slopes of Mount Kilimanjaro or in the snowfields outside of Juneau, Alaska, and that sea ice in the Arctic is thinner now and less extensive than ever. In fact, as I write this, satellite images reveal that Arctic sea ice is at its lowest extent ever, raising the prospect of a Northwest Passage entirely open to shipping. Perhaps even more dramatically, we know that the Antarctic Peninsula, which juts northward toward Chile, is one the most rapidly warming regions on Earth. On the peninsula’s west coast, mean annual temperatures have increased 2.9 degrees Celsius during the period 1950 to 1999 and winter increases have averaged an extraordinary 5.5 degree Celsius rise over the same period. The retreat of the Larsen-B ice shelf, beginning in 1998, and its rapid collapse in 2002 have been attributed to warming air and water masses in the region. The Larsen-B collapse was vividly described by Christina Hulbe of Portland State University as “a profound event. This ice shelf has endured many climate oscillations over many thousands of years. Now it’s gone.” Temperature effects on the West Antarctic Ice Sheet and on ice in the vast continental interior are subjects of intense research and debate, and it has been estimated that melting of the ice sheet in West Antarctica alone would contribute an additional twenty feet to sea level—a change that would require the map of the Earth to be redrawn.

The increase in regional and global temperatures—the latter predicted to increase by 1.4 to 5.8 degrees Celsius by the year 2100—is no longer a mystery. Human activities, from the Industrial Revolution to the present, have altered our atmosphere by, in effect, vaporizing long-stored deposits of coal and oil and sending them skyward transformed as the greenhouse gas carbon dioxide. The long Antarctic ice cores, collected near Vostok Station, show that at no time in the 650,000 years prior to the Industrial Revolution had the concentration of this gas been higher than 300 parts per million (ppm). Today, carbon dioxide values stand at 380 ppm, and rising. In addition, our varied activities across the globe—cutting forests, planting rice, developing new products, expanding agriculture—are contributing even more greenhouse gases, like methane, nitrous oxide, and CFCs. As Alan Weisman has noted in The World Without Us, “Among the human-crafted artifacts that will last the longest after we’re gone is our redesigned atmosphere.”

Of all Earth systems, the atmosphere has always been the most vulnerable. The German astronaut Ulf Merbold called it “a fragile seam of dark blue light,” and geochemists have long commented on its relatively tiny mass when compared with the oceans and the Earth’s crust and mantle. It was in the atmosphere that we first noticed change on a truly global scale, with James Lovelock’s observations that chlorofluorocarbons had migrated from the northern to the southern hemisphere and that most of the tonnage released, largely by aerosol spray cans at that time, had remained unchanged in the troposphere. Sherwood Rowland and Mario Molina predicted in the early 1970s that the fate of these compounds would be to rise into the stratosphere and, once there, react with ozone. It took more than a decade for this prediction to be confirmed by Joe Farman, Susan Solomon, and others over the Antarctic continent. A series of conferences, beginning in Montreal, resulted in a ban on chlorofluorcarbon production, but the long lifetime of these compounds (measured in decades to more than a hundred years) ensures that the problem of ozone depletion will be with us well beyond mid-century.

The illusion that human beings are insignificant actors on the global stage, in comparison with the mighty forces of nature, has taken some time to fade. I recall reading an essay by the great explorer Thor Heyerdahl about one of his last ocean voyages. In it, he spoke of how everywhere on the open sea he could discern the signature of man, most disturbingly in the form of the unsightly tar balls that washed against his raft. His point was that what we had once considered to be limitless—the uncharted seas of Cooke and Melville—were nothing more than expansive, closed-basin, lakes, finite in size and corruptible by our collective onshore activities. There has been a shift in our conceptual geography: from thinking of the Earth as being limitless and vast beyond our comprehension to being what it truly is, “a pale blue dot” in space, finite and vulnerable to the prodigious force that we—the six billion of us—have become. The chlorofluorocarbon story amply confirms this, as does the sadly personal and prescient account of climate change that Bill McKibben has offered in The End of Nature.

Water, Ice and Stone is set in the McMurdo Dry Valleys, a place where it may still be possible to imagine that the Earth abides unchanged. I recall once having climbed to a certain height in the Asgaard Range far above the floor of Wright Valley and the frozen surface of Lake Vanda. When I turned around and sat for a moment to rest, I was struck by the fact that I had been here, in this same spot, nearly thirty years before and that nothing had changed. Nothing. The same river, the same lake, the same blue, flawless sky, the same untouched land, the cold. It was a happy thought. And yet it lasted only a second. For indeed much had changed. The ultraviolet radiation from the sun now poured over me with a far greater intensity than before; and the very air that I breathed had been transformed over those decades so that it now contained some thirty percent more carbon dioxide than it had when I last had this view. While I could not detect the change, all the instruments agreed: things were different now, and I knew that we human beings, a major force on our small planet, were the cause. Though I could not detect it with my senses, the air I breathed was in some way, as McKibben noted, artificial, man-made. Even here!

The McMurdo Dry Valleys are an atypical region of the Antarctic continent. Slightly greater in area than the state of Rhode Island, they seem little more than patches of dry earth pressed between the silver expanse of the Ross Sea and the vast interior ice sheet of East Antarctica. Most of the writings about this place have been the writings of scientists. There has been no diarist to chart this wilderness, no poet to capture its solitudes. Between the early explorers and the few recent essayists, painters, and landscape photographers, the valleys have been described largely in the technical literature of biologists, geochemists, geologists, and paleontologists. These are the people who have walked this land, who have labored and camped in it, and felt it in their bones. What has been communicated to the public has been done through the rare television special or through the photographs of artists like Craig Potten or Eliot Porter.

But the technical summaries of scientific research offer a portrait of the land that is rich and compelling and that sets a broad universal context for what has been learned and carried away from this remote place. For the valleys are treasure troves of information about ancient landscape processes and about the quality of life in extremis, where, somehow, living matter gains a foothold in rock and ice and adapts, flourishes even. To know that in seemingly lifeless soils there exists a community of nematodes that live among yeasts and bacteria and filamentous fungi in a frightening matrix of coarse stone and bitter cold is to be reminded of life’s tenacity, its elemental toughness.

In the technical scientific literature, a curiously poetic term has been used to capture the essential mix of elements that interacts and gives identity to the McMurdo Dry Valleys and that sets them apart from landscapes anywhere else on Earth. The word is mosaic, and it seems an appropriate one, for, in one of its senses, it means a pleasing picture or design made by arranging small bits of colored stone or glass in a matrix. When the term is applied to the Valleys, it refers to the inlaying of glaciers, ephemeral streams, permanently ice-covered lakes, exposed bedrock, sandy soils and richly patterned ground. And perhaps more insubstantially to the vast exposures of geologic time and to the ever-present wind, which works its way into the psyche of anyone who has ever spent a season in the mountains or on the surface of a lake. These are the figurative “bits of stone,” the “shards of glass,” the raw elements of place and identity. To enter this land is to become part of a mosaic that is at once unexpected and frightening, beautiful and sheltering, timeless and yet touched with the tracings of time. Like William Blake’s world in a grain of sand, it is possible from this remote vantage point to envision—in fact, to experience—the turning of the Earth’s great geochemical cycles.

In the years since the first printing of Water, Ice and Stone, the Dry Valleys have assumed a far greater scientific importance. They have become the setting for intensive investigations under the auspices of the National Science Foundation’s Long Term Ecological Research Program, and the biologist Edward O. Wilson begins his Future of Life with a description of the extremes of aridity and temperatures that challenge even the hardiest microscopic organisms in this setting. “On all of the Earth,” Wilson writes, “the McMurdo Dry Valleys most resemble the rubbled plains of Mars.” Moreover, the ice-covered lakes, which are pellucid and striking and so oddly out of place in this driest of deserts, serve as indicators of climate change, both in the thickness of their ice and in the structure of their salinity profiles. On timescales of decades to millennia, the lakes are unique ledgers of subtle or pronounced changes in the climate of the region. Understanding what they are telling us is more important now than ever.

While this book was not intended to be a study of climate change, it was meant to convey the many linkages that exist—through the cycles of water, carbon, calcium, oxygen, and many other elements—between ourselves and the Earth. In some ways it became a meditation on this very subject. The chapters “Science and the Shell,” “The Sea,” “The Flume,” The Cone of Erebus,” and “Cathedrals” all refer explicitly or implicitly to the great carbon cycle which links us and all of the creation to the solid Earth and to the sea and the atmosphere. It is the carbon cycle that we have so profoundly altered, and these alterations will be the concern of our own and of generations far into the future. We are only now beginning to recognize this.

In the chapter “The Moat,” the seasonal shape of the carbon dioxide curve—a subject explored in Al Gore’s An Inconvenient Truth—is described in global terms:

All over the world, this shallow breath of the Earth is signed upon the air. The signature rises and falls through time, in a sinuous curve. You could not mistake it for anything else but the Earth’s breathing. It is the curve of carbon dioxide through modern time, its concentration in the atmosphere, plotted month after month—the Keeling Curve. From the slopes of Mauna Loa on the Big Island to the desolate wyomings of Pole Station—where the sleepless recorders work day and night inhaling the air, taking its measure—the patterns are the same: In the spring of the northern hemisphere, the carbon dioxide of the atmosphere declines as the trees unfold, as they imbibe water into their roots and carbon into their leaves, as the warming seas ripen with phytoplankton off Peru and California and Cape Cod. The sweet yearly inhalation and budding, fecundity and opulence and color everywhere spreading like a blush and holding. All through spring and summer the Keeling Curve falls. In autumn and winter it rises, when in fields and empty lots, in forests and swamps, and in the gray winter of the sea, carbon dioxide is returned to the air.

These are precisely the connections that have been drawn in recent years by those seeking to model the carbon cycle and to predict the influence of our dependence on fossil fuels.

The rising Keeling Curve is the signature of human activity written on air, and the scientific community no longer doubts the role of our industry, broadly construed, as the engine of atmospheric change. This change is certainly in evidence at the Poles and in receding glaciers across the globe and in migrating species on land and at sea. How much ice we are likely to melt and when—in Greenland, in West Antarctica, and on the huge East Antarctic Ice Sheet—is a subject of intense discussion. What actions our increasingly clear scientific knowledge should require is also a matter for debate. Between what we know and how we act falls the shadow, to paraphrase T. S. Eliot. And policy decisions in the wake of scientific evidence, regardless of how persuasive, have always been difficult to formulate. The phase-out of chlorofluorocarbons took some thirty years after the original work of Rowland and Molina; and carbon dioxide reductions, given the role of fossil fuels in every facet of our economy and in the economies of developing countries, will certainly be a far more vexing problem for the nations of the world to solve. Signals from Antarctica and from other frozen shores may well be the prime movers in a resolute global effort to arrest what has been a long assault on the Earth’s most fragile reservoir.

Reviewers of Water, Ice and Stone clearly saw the environmental concerns that it raised and the cycles that it highlighted. But they also saw more. Perhaps more than I had seen myself. Philip Zeigler, for example, in his remarks for the John Burroughs Association, commented on the idea of transformation that runs throughout the book:

Like all lakes, those of the Antarctic are fed by streams which bring to them the detritus of the surrounding land: nutrients, metals, organic and inorganic elements, which are somehow transformed in their passage through the lake. Because of their very isolation, their detachment from the often cataclysmic changes man is continually making in the physical world, they allow us to trace the way in which the elements of the Earth, dissolved from rock by the action of water, are reconstituted in new forms. They can provide clues about how bodies of water are formed, how they vanish over time, and what happens to their elements. The central process here is a chemical one, a process of transmutation of earth, water, ice, atmosphere in an endless cycle from one form to another.

While the science of Antarctica has assumed an ever greater significance, in light of human-induced changes to the atmosphere and in light of the virtual certainty of a warming planet, the value of the place as a center for contemplation and reflection remains as it was when I wrote the book. Questions about the nature of science and creativity, the choice of one’s profession, the connectedness of things in personal and geological time, the coexistence of beauty and death in the same mix, the distinction between solitude and loneliness, the hidden importance of the global cycles, especially those of water and carbon—these are enduring human concerns.

Water, Ice and Stone is a difficult book to classify. It is a travelogue, a scientific quest, a memoir, a hymn to the water molecule, and perhaps, as one reviewer noted, it is “a braided river” where all of these join as one. In one of his essays, John Burroughs said that “it is sympathy, appreciation, emotional experience, which refine and elevate and breathe into exact knowledge the breath of life.” In his own writings, he showed how the two—precise scientific knowledge and personal response—could be joined. It is in this tradition—what has come to be called “nature writing”—that the rational and romantic impulses merge. What is impossible in the scientific paper, the full expression and evocation of one’s immersion in a particular place and time, are the sentiments that the naturalist essay welcomes: the cold, the sight of clear water, the sense of presentness, of being alive here, now. What is difficult to achieve in poetry and literature—straightforward discussion of process, cause and effect, a deep appreciation of number, law, and the depth of things—the naturalist essay, as practiced since Thoreau and Burroughs, easily assumes into itself.

It was my hope when I wrote that first journal entry, and it is my hope now, many years later, that Water, Ice and Stone will be viewed as a work that brings both of these traditions, the scientific and the literary, together. It is also my hope that readers will find in these pages some reason for optimism. For our studies of the lakes of the McMurdo Dry Valleys have shown once again nature’s powerful resilience, have shown what is generally known: “that in every lake and ocean, in every parcel of atmosphere, there is a cleansing that tempers the Earth, that drags it back from squalor, that countervails its self-undoing.” I should have said, too, that countervails what we, ourselves, have done. If we are truly lucky, these words, in time, may also apply to the profound alterations we have made, and continue to make, to the global carbon cycle and to the thin band of air—that “fragile seam of dark blue light”—into which it is so tightly woven.