Global View
In an excerpt from his new book, the eminent geologist contemplates the meaning of sustainability
By Frank H. T. Rhodes
For the last 3.5 billion years the Earth and its systems have shaped the lives and influenced the behavior of all its inhabitants. And the inhabitants, in turn, have had a significant impact on the surface of the planet that gave them birth. Think, for example, of the huge influence of early bacteria in providing the initial oxygen of the atmosphere. Or consider the continuing role of plants in the carbon cycle.
But for most animals, this interchange has been more one-sided. Earlier generations of humans were, like most of their fellow creatures, far more dependent on Earth’s bounty and far more influenced by its forces than Earth was by them. For most of our ancestors, every dimension of life and every aspect of day-to-day existence was constrained by the planet. Human life exists by courtesy of the planet: it came into existence in adaptation to Earth’s conditions and it has survived only as it was able to adapt its behavior and accommodate its activities to the continuing and changing constraints the Earth imposes.
A little over 250 years ago that simple pattern of indenture began to change. Until then, food supplies were largely local, their character and even their availability heavily dependent on local climate, soils, and crops, and on a handful of easily hunted or domesticated local animals. Implements were manufactured largely from local materials, whether stone for early weapons and implements, iron for tools, or clay for pottery. Building styles and architectural forms were also local or regional in character, reflecting the availability of freestone for construction, clay for bricks and tiles, timber for framing and shingles, slate or thatch for roofing. Patterns of settlement and trading were no less influenced by local geography and convenient water supply. Wider migration and trade, such as they were, depended on navigable rivers, protective harbors, and favorable winds.
With the coming of the Industrial Revolution, the age-old influence of these physical constraints rapidly declined. To the energy long supplied by human effort, wind, water, wood, and animals was now added fossil fuel—first coal, then oil and natural gas—and later nuclear power. And this brought a revolutionary increase in human empowerment, and with it not only dramatic changes in individual lifestyles, but also a growing human impact on both the planet and its other inhabitants. Mining and quarrying, drilling and blasting every corner of the Earth, humans now began to exploit it on a scale scarcely imaginable in earlier times. Burning fossil fuels in a growing array of new devices—from domestic stoves to industrial smelters, from steam locomotives to jet airplanes—manufacturing, agriculture, travel, communications, and human society itself were transformed. Nor was this all, for with this transformation in human power went explosive growth in human numbers, and, with both, an enormous increase in human impact on the planet itself. Rivers were dammed, drainage patterns were modified, forests were felled, coastlines were reconfigured, prairies were farmed, estuaries were drained, and the surface of the planet shaped and sculpted to suit a world of human needs. Above the Earth, the atmosphere, too, was changed and the global climate modified to an extent and with a rapidity that were unprecedented in recorded human history. It is as though, one reflected, we were absentmindedly conducting a whole-Earth experiment in real time.
All these changes our ancient planet will survive. It has repeatedly shown its resilience throughout its long history. So, too, will life. It has survived waves of global extinction long before we appeared on the scene. It is not Earth’s sustainability that is in question. It is ours. And our sustainability requires the planet to remain habitable, able to sustain not only our own species but the countless others on which the intricately balanced economy of our present existence depends. It is that sustainability that we now examine.
Sustainability involves Earth’s ability to continue to supply our basic needs. But what’s our most basic need? What resource is most critical to our survival? Food perhaps? Certainly, food is essential. We can’t long survive without it. But food—whether vegetable or animal—requires soil, and soil requires water. Each of us needs about two and a half liters a day just to keep our bodies functioning. Maybe water’s equally basic. So, of course, is air—clean air. And so is energy. No energy, no food production. No energy—no heat, no light, no fuel. And minerals—stone, metals, materials. No minerals, no tools, no shelter. So it’s not just one basic resource: it’s all the above. Put all these together—food, soil, water, air, energy, minerals—and you have Earth and its components. We need them all. They’re all connected. It’s in the interplay of Earth’s endless cycles of interacting systems that these resources on which we depend—Earth’s bounty—are produced and sustained.
Now the definition of sustainability requires refinement and clarification. Suppose we say that sustainability is, “Meeting the needs of the present generation without compromising the ability of future generations to meet their needs.” That definition—often called the Brundtland definition, after the former prime minister of Norway, Gro Harlem Brundtland, whose commission coined it—is broadly ethical. Other, more precise, definitions involve a social equality component, requiring the elimination of hunger as a necessary definition or a certain level of income or food supply, for example. Still other definitions are economic. Thus Herman E. Daly of the University of Maryland gives an operational requirement that the rate of use of renewable resources must not exceed their rate of generation, that the rate of use of nonrenewable resources should not exceed the development and supply of alternatives, and that pollution rates should not exceed Earth’s natural restorative capacity.
My colleague at Cornell, Norman Scott, PhD ’62, suggests a more comprehensive definition: “Sustainable development is a process of change in which the direction of investment, the orientation of technology, the allocation of resources, and the development and functioning of institutions meet present needs and aspirations without endangering the capacity of natural systems to absorb the effects of human activities, and without compromising the ability of future generations to meet their own needs and aspirations.”