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