by Sarah Dry
If much gets put into global knowledge, it is equally important to remember how much gets left out. Just because we are all on this planet together does not mean that each voice can speak equally loudly. That is obvious in the realm of politics, but it is less obvious when it comes to telling the histories of science, where the story of creating global knowledge is often taken for granted as a story of unmitigated progress. This narrative of progress is, to a greater or lesser extent, the melody by which all histories of science tend to get sung. Science is understood, fundamentally, as a progressive human endeavor. And in some senses it is. But in other senses, it is equally a process of elision, excision, and exclusion.
Big ideas are often invisible, so influential that we can no longer imagine looking at the world in any other way. We think we are simply seeing things the way they are. The idea of the earth as a global system of interconnected parts is a case in point. It is so basic that even those who still question the reality of anthropogenic climate change share it. The idea that there is a global climate is rarely a topic of debate (though when you start to think about this, it is hard to say what—or, more to the point, where—such a climate might be). The debate has hinged instead on whether the global temperature is rising or falling, or, as the rise becomes increasingly hard to deny, what the future will look like. The idea that there is a climate system, a set of natural features that are interrelated and function at the global scale—well, that has come to seem obvious.
What is the history of this “obvious” fact? Many point to the famous “Blue Marble” images taken aboard the 1972 Apollo 17 NASA mission, images that gave us our first glimpse of the planet as a whole. Seeing Earth like this, the story goes, was a revelation. We grasped, finally and instantly, the fragility, the uniqueness, and the interconnectedness of everything on the planet. The vision of the dazzling Earth rising above the barren surface of the moon did give a big boost to the burgeoning environmental movement. But we were already primed to see Earth that way. The space race was more a product of the previous successes of a global vision of the planet than it was a producer of it. Long before Sputnik and the Apollo missions, scientists had helped craft a vision of Earth as a globally connected object out of countless investigations into the physical complexity of our planet.5
Gaining a better grip on the breadth of knowledge that constitutes climate science today is essential for understanding what we know and what we don’t know. The tendency to judge climate science by its predictive abilities has serious consequences for how we make decisions, as citizens and nations, in the face of uncertainty about the future. Our contemporary expectation that climate science can and should make predictions about the future indicates the long shadow of that old “pattern” science, astronomy, still extending over us today. But within what is too often monolithically referred to as climate science, there are many different methods for generating knowledge. These methods are sometimes called subdisciplines. For the story of global climate knowledge, they include geology, climatology, meteorology, atmospheric physics, glaciology, and computer science. In order to understand how our knowledge of the planet has come to feel global, we need to understand how these disciplines within the larger body of science have come to seem interrelated. The history of our knowledge of the planet is necessarily the history of the disciplines (and all their associated practices, pedagogies, instruments, techniques, and social structures) that have generated that knowledge. To create a singular global climate, in other words, it was necessary to forge a unified climate discipline out of many parts in just the same way that it was necessary to find ways to bring what had previously been disparate pieces of knowledge—of this place, say, or this type of object—together.
To understand the nature of climate science (understood broadly) requires going back to the particulars out of which it has been generated. This means places and people. My previous two books are biographies (one about Marie Curie, the other about Isaac Newton’s manuscripts), and my instincts are biographical. So that is what I have chosen to do here. People, not water, are the true subjects of this book. These people are scientists. The oldest of them was born in 1819. The youngest was born in 1923. I watch the planet with their eyes, take a journey through the past with them as companions and investigators, as explainers and exclaimers. This investigation of watery things is, then, very much a grounded one, planted firmly in the personal experiences of a remarkable group of thinkers.
I begin in the 1850s with the first attempts to measure changes in climate and weather simultaneously and at a global scale—the beginning of both modern weather forecasting and climate science. It is here that I also trace pioneering studies into the importance of the atmosphere in regulating the climate—at a time when no one dreamed that human beings might affect the temperature of the earth as a whole. Yet this was also the time when the new science of thermodynamics seemed set to crack open untold mysteries not only of the earth but of the entire universe. New equations could explain the behavior of molecules statistically. It remained to be seen whether these equations could also explain the movement of molecules in the real world of glaciers, clouds, and water vapor.
In the 1850s, it was glaciers that threw up the biggest challenge of all to scientists hoping to explain their motions, and, by extension, the past and future of the earth’s climate. Although the ice ages are now a taken-for-granted fact, they once seemed both real and inexplicable, a puzzle of mind-boggling extremes to be solved on a global scale. John Tyndall sought answers to these deep questions of time, movement, and decay surrounded by the deadly, searing beauty of Alpine mountain glaciers and, on his return to London, in the confines of his basement laboratory. His findings on how heat acts on ice and water vapor reveal an obsession with energy, with dissipation, and with the past and future of the planet.
In 1856, Charles Piazzi Smyth, a Scottish astronomer and scientific traveler, tried initially to subtract, or to erase, the presence of water vapor from his astronomical researches atop a high volcanic peak in Tenerife, one of the Canary Islands. Later, he hoped that the study of water vapor with a powerful and highly portable new instrument could help make weather prediction safer, more respectable, and possibly even successful. He failed in that endeavor, and tarnished his reputation with a passionate defense of the idea that the British measurement system had been divinely inscribed in the Egyptian pyramids. Finding himself outside the scientific establishment, he sought solace in a peculiar blending of religious and scientific witness, a photographic cloud atlas he attempted to assemble alone, in his final years as an isolated, embittered, but always reverential scientific pilgrim.
Both Tyndall and Piazzi Smyth strained to contribute to a predictive science that could account precisely for the actions of water—of the movement of glaciers, of the action of water vapor, of the formation of clouds and the falling of rain—and both welcomed the feeling of mystery and wonder that accompanied their investigations even as they attempted to describe the world dispassionately. These men experienced the inherent contradiction of these two positions with a passionate, even visceral intensity. Their stories capture the torment this Victorian generation experienced as they attempted to reconcile science’s potential to reveal the hidden structures beneath the wild confusions of the earth’s environment with the loss that might accompany such revelation. Would the gain in understanding compensate for the forfeit of mystery? In many ways, Tyndall and Piazzi Smyth were members of the last generation of scientists for whom such an existential struggle had an acceptable public face. They published books that invited general readers to feel their fear, wonder, and awe as they encountered sublime phenomena such as cloud forms and majestic glaciers. And then they tried to reduce these phenomena to numbers, equations, and theories that could not merely explain but also predict the most intimate details of what had previously been, almost by definition, ineffable.
The story of Gilbert Walker, a preternaturally talented English ma
thematician, provides a transition between the nineteenth century, when individuals could still express scientific ideas in books for the general public, and the twentieth century, when dry scientific papers replaced the dramatic travel narratives written by men like Piazzi Smyth and Tyndall. When Walker became director of meteorological observatories in India, many believed that the key to unlocking the secrets of the monsoon rainfall, upon which millions depended (and still depend) to sustain their crops, lay in the cycles of spots on the sun. Walker’s statistical inquiries, made possible by the access to weather data gathered via imperial networks and by the hard work of local calculators employed by the British government, destroyed the cherished hopes of the sunspot theorists. In place of the congruent, or coherent, harmonies of sun and Earth, Walker offered a statistical discovery of amazing scope. His calculations indicated a connection (actually a tele-connection) between the monsoons in India and pressure and temperature halfway around the world. Walker named the phenomena of linked meteorological phenomena “world weather,” and, more specifically, the one affecting India he called the Southern Oscillation. Unlike Tyndall, who was committed to demonstrating the links between physical phenomena, Walker’s scientific insights were purely statistical. He could not explain how pressure in the west Pacific affected rainfall in the Indian Ocean; he could only say that it did. (In fact, it was another forty years before the physical links that drove the Southern Oscillation could be explained.)
A golden age of physical oceanography and meteorology was initiated by a bolus of funding and urgent practical need for information about air and water during World War II. It continued in the Cold War for decades thereafter. This was a time of big pictures built on remarkably simple models, characterized both by new kinds of international cooperation and by the tensions of realpolitik. Henry Stommel was a young man in 1948 when he published a paper explaining why every ocean basin in the world has a fast-running current on its western side. His fruitful thinking led the way for a new generation of oceanographers who showed that the ocean was moving in a much more complex and energetic way—on a multiplicity of time and spatial scales—than previous generations had imagined. In so doing, Stommel set the stage for an ocean characterized largely by its turbulence rather than its stability and a new way of doing experiments in the ocean that required large-scale and long-term cooperation, something Stommel himself intensely disliked. At roughly the same time, Joanne Simpson investigated how the relatively small-scale dynamics of clouds could drive atmospheric—and oceanic—circulation on planetary scales. She also sought new ways to do science—using instrumented aircraft and canny cooperation with government agencies to experiment on clouds, and even hurricanes, by seeding them. This work on weather and climate modification took place against a backdrop of anxiety about the threat of attack from the Soviet Union. These water stories show how a connected Earth can be a vision of war just as much as of peace.
Individual scientists were both pawns and hustlers in this worldwide game of scientific chess. When the Danish physicist and meteorologist Willi Dansgaard realized that the new mass spectrometer he had access to could be used to sort water molecules by weight, he was following his own private intuition. But to follow his insight to its fullest conclusion, he had to convince the largest and most powerful national and international scientific (and sometimes military) agencies to give him access to technologies he would never otherwise be able to afford. The story of ice cores and the history of past temperatures (or “palaeothermometry”) is a story of individual cleverness, tenacity, and diplomacy played out against the backdrop of the Cold War. Dansgaard’s contribution helped change our understanding of past climate and laid the foundation for the first glimmerings of what would become our contemporary awareness of global climate change. But, as I show, the assumption that one part of the planet—in this case, the northern Greenland ice sheet—could umproblematically speak on behalf of the whole turned out to be, in important particulars, inaccurate. The idea of global changes captured in ancient ice turned out to be more important than the facts recorded in those cores.
For all the triumphs these scientists enjoyed, their stories are also threaded with loss. The loss is often personal—one scientist cannot make human relationships work, another suffers a crippling nervous breakdown—but it is also existential. Global knowledge of the kind these scientists create has often been prompted by questions about changing conditions on the earth. New knowledge also prompts new questions about our relationship with what we know, how we know it, and how we should feel about that knowledge. The role of mystery, ignorance, and wonder in the pursuit of science and the implementation of its findings remains as important as ever, though we have lost the Victorians’ readiness to acknowledge this fact. In its attention to the role of sentiment, awe, and longing, this book is as much a history of emotion as it is a history of science.
While we are today preoccupied with our own anxiety about the effects of human-induced climate change, previous generations have voiced different concerns. In the light of our modern awareness of global warming, these early investigators constantly seem to be getting it wrong, to worry about irrelevant things, to miss what seems to be right in front of them. But of course it is we who are getting it wrong if we look backwards only to find what we think we know today. Instead, I revisit the passionate commitments of these scientists from the past to better understand what it was that motivated them. These include Tyndall’s melancholic conclusions on the implications of the second law of thermodynamics, the millennial anxiety caused by nuclear weapons testing in the 1950s and 1960s which released radioactive elements into all parts of the water cycle, and the flip-flopping worries about the effects of widespread cooling and global warming in the 1970s. Less dramatic but perhaps even more fundamental is the shift from relatively simplistic models of ocean and atmospheric circulation to models that are fundamentally chaotic. Such a loss of even the possibility of certainty casts the crisis around climate change further into the shadows of political contestation. If science cannot give us certainty, goes the argument, what can? Will we need to invent new kinds of knowledge, new ways to know what Earth is? Or will we need to let go of the idea of certainty and embrace a changing planet?
In Tyndall’s book on The Forms of Water in Clouds and Rivers, Ice and Glaciers, he talks his reader (to him readers were listeners, and texts like stories frozen on the page) through a world he’d explored for many years and come to love. It is a water world full of such energy and movement that it feels alive, though living creatures are notably absent. Banners of cloud stretch, crevasse-slashed glaciers buckle, and crystalline lake-ice cracks. Above it all swoops Tyndall himself, taking in hand an imaginary listener who, he admits, has become to feel so lifelike to him that by the end of the exercise he feels real affection for the “abstract” boy. Tyndall is like that: He can’t help bringing things to life, be they imaginary boys or frozen landscapes.
The book you hold in your hands puts water to a similar purpose. It uses stories of water, as Tyndall did, to animate the most inhospitable and lifeless spaces on Earth—the deepest recesses of the open ocean, the vast ice sheets of Greenland and Antarctica, the water vapor that suffuses the farthest reaches of the atmosphere. While Tyndall made his imaginative voyages in order to share with readers the wonder of the natural world, the wonder I want to share is historical. How have our water stories changed over time? What do these changes tell us about what we know (and what we think we know) about the planet today? How can they help us prepare for a future that remains, as it must, uncertain?
2
HOT ICE
We can begin anywhere. As John Tyndall has made abundantly clear, all things are connected, and to pull a thread from one part of his life should reveal the warp and weft of the whole. So let’s start here, in the place he most loved to be: on the side of a mountain in the Alps. It is December 1859 and John Tyndall, aged thirty-nine, is walking up a mountain. He puts one f
oot in front of the other in an easy rhythm. A wiry man, he disdains eating while he is on the move. His friends call him the goat. The sky is radiant blue, deeper and clearer than it ever is in London. The peaks and pinnacles are craggy ruins. The glaciers are pristine, the snows of winter blanketing the pocks and streaks caused by summertime melt. The clouds are almost but not quite more than Tyndall can describe.
He carries very little with him. A notebook, a flask of tea, a hard biscuit jammed in his back pocket. A walking stick with his name engraved in a charred and wiggly line by his friend Joseph Hooker with a pocket lens and the sun’s heat. A pair of good boots and a kerchief tied around his neck against the cold. Reluctantly, he has employed two guides and four porters to accompany him.1 Though they carry his heavy gear, he’d rather travel solo. The mountain is a balm to him in proportion to his solitude and the level of danger he faces. Danger is cheap on the mountainside, available to him at half a pace’s shift to the left or right. A loose rock, a long slide into oblivion. Other dangers are available, too. The seductive embrace of the cold if taken unawares by a snowstorm. Collapse brought about by overexertion in the thin air. So far Tyndall has been lucky, and he has been careful. He does not seek thrills, only catalogues them as he climbs, his eyes darting this way and that, from trail, to precipice, to the skies overhead. His mind is busy with this cataloguing, and this frees him from thinking of other things. His life back in London as professor of natural philosophy at the Royal Institution. The unfortunate tendency he has to dispute. The lonely whirring of his mind during an insomniac night, followed the next day by a cottony head, dry eyes, and a racing heart.
He puts one foot in front of another and watches the skies. The morning clouds clear so evenly, it is as if a dial has been turned by a deliberate hand. Tyndall knows that the water has not disappeared, only become something else, an invisible vapor rather than a spray of fine droplets. He stops for a rest and kicks a rock, just to see where it goes. It falls close to the mountain and then hits the side to make a huge bouncing arc into the thin air, before falling back against the mountain and bringing down a rain of smaller rocks that Tyndall can hear, like gravel on a roof. There, he’s done his bit to bring the mountain down one tiny increment farther. If he thinks too long on it, the decay of the mountain makes him melancholy. He cannot help unspooling his thoughts further into a cold and dismal future, to a time without humans, without life and without even the heat of the sun.
