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The Forgiving Air: Understanding Environmental Change

University of California Press

The Forgiving Air, a brief line from a powerful poem, is a great poet's characterization of an environment of rich fecundity, sustaining an abundant mosaic of life, an environment that is at once beautiful, fragile, ephemeral, and mutable. Elizabeth Bishop's "Song for the Rainy Season" is set in Brazil, in the town where she lived, Petrópolis, which is in the mountains about 60 miles inland from Rio de Janeiro, close to the Tropic of Capricorn. The poem reminds us not only that climate can vary, but that it does so spectacularly every year, as the seasons change. In Petrópolis, as elsewhere in the tropics, the contrast between the dry and rainy seasons can be especially dramatic. For me, that contrast is an apt metaphor for the global changes that people may inadvertently cause by affecting our planetary environment. As the poet warns us, "a later era will differ."

It might be a great comfort to us all if our planet and its climate were constant and unchangeable. They're not. They've been changing naturally for as long as the Earth has existed. Today, however, the people on the planet are collectively such a potent force that their influence on the global environment has begun to rival that of Mother Nature herself. This is in fact a unique moment in human history. We—all of us—have begun to affect the Earth on a global scale. We have of course been affecting the planet in our own neighborhoods for a long time. People were dying of smog-induced illness in London centuries ago. But now there are so many of us—nearly six billion, and more all the time—and we use Earth's resources so profligately that we can alter not

just our own neighborhoods but the character of the entire planet. We thus live in a remarkable time, one that can come along only once in human history. That moment hadn't yet been reached even in our grandparents' generation, but it's upon us now. So it's no coincidence that the topics we'll focus on in this book are all occurring at the same time.

The ozone hole, the dramatic depletion of stratospheric ozone over Antarctica, is one of them. It's a fascinating story, and its outcome is not yet known. But it's not the only important aspect of global change. The greenhouse effect, acid rain, and air pollution are others, and the list continues.

We'll begin with the ozone hole. Then we'll take up the greenhouse effect, perhaps the paradigm problem of global change. The prospect of increasing the greenhouse effect, and thus altering Earth's climate, worldwide, illustrates many of the most important and characteristic features of global-change problems. Climate change is international in scope, it occurs slowly over many decades, and there is no simple way to retard or reverse it. Later we'll move on to such topics as urban smog and acid rain.

Two themes will recur throughout this book. One, which I've already mentioned, is the issue of our having become so numerous as a species—and our industries, lifestyles, and energy usages having accordingly changed so dramatically—that we, the human race, have begun to affect the planet in ways that we hadn't expected, ways that are global in scale.

The second general theme is the role of science in all this. I've chosen to talk about the ways in which we're affecting the planet on a global scale because they involve some of the most exciting, most promising, and most relevant science that's being done today. the topics I'm going to spend most of the time on concern everybody: they're in the headlines, they're on television, and they excite people.

Today, in the graduate schools where scientists arc educated, a different kind of student is coming to study environmental science. Students who might at one time have chosen to study astronomy or quantum mechanics are instead choosing careers in Earth science. They're motivated by the fact that science on these topics has planetary ramifications. These students are as passionate about their research as they arc about our stewardship of the world. They're interested in doing science that's relevant to the environment and to the planet.

Science is inherently unpredictable and often surprising. The story of the ozone hole, which we'll examine shortly, illustrates this well. Ozone is a gas that occurs naturally in small quantities in the region of the upper atmosphere called the stratosphere. Ozone has been studied by scientists for many years as a more or less abstract research problem. That is, some of them were interested in ozone simply for the sake of gaining more knowledge, not necessarily because they were worried about the possibility of destruction of the ozone layer or even the loss of a small fraction of the stratospheric ozone. As we shall see, the fact that these scientists were interested in ozone for its own sake led to a remarkable and completely unexpected discovery of paramount importance.

Basic research is often that way. An investigation carried out with no particular application in mind, a modest little foray into the unknown, often turns out to be tremendously important in ways nobody could have foreseen. A classic example is the work of Albert Einstein, which revolutionized physics. Nobody knew in advance that Einstein was going to do anything important. He was completely unknown to the world of science. He did his first breakthrough research, the work that led to a Nobel Prize and worldwide fame, entirely on his own while earning a living as a minor official in a patent office in Switzerland. His only motivation was insatiable curiosity; his only resource, his brain. The theory of relativity didn't emerge from a famous university, or even a mediocre one, but from a patent office!

Thus, whenever an unscrupulous or misguided journalist or politician grabs a headline or a soundbite by making fun of a science project with a silly-sounding name, real scientists cringe, because they know that nearly all of the most important accomplishments in science, including those that have led to great benefits for humanity, are founded on basic research. The obscure project of one unknown scientist today, which may seem silly or inconsequential, especially to a nonspecialist, can have major implications tomorrow.

Of course, not all basic research leads to wonderful and important results. Sometimes, projects yield nothing at all. More often than not, the chain of events that does lead to an application is long indeed, the later events almost imperceptibly linked to the founding events, and the genealogy of a discovery can therefore be hard to trace. Science, especially basic research, is thus chancy and inefficient by its very nature. When we pay for it—whether we are members of Congress or ordinary taxpayers—we need to recognize that fact explicitly. Appropriating money to support research is a form of investing in the future, and all

investments entail risk. We can and should be very careful when we choose which science we will support, but we ought to face squarely the reality that some of what we're funding will turn out to be pathbreaking, some will not, and it's absolutely impossible to be sure in advance which is which.