The implications of sustainable development become more difficult to sort out with respect to non-renewable resourcesfossil fuels, minerals, and so forth. On the surface, it is obviously impossible to use a non-renewable resource "sustainably"; each unit of a non-renewable resource used is one less unit from a finite pool.57 But it is not immediately clear whether and how non-renewable resources such as oil, gas, and minerals should be conserved. It is not even self-evident that running out of a resource necessarily impinges on the ability of future generations to meet their needs.
For example, using whale oil in the nineteenth century as an input for energy or manufacturing was clearly unsustainable. And obviously it wasn' t sustained. The hunting of whales to near extinction may have threatened the biological diversity of the planet, but the depletion of whale oil as a resource did not impede succeeding generations from growing and meeting their needs, and, not coincidentally, protecting and restoring the whale population at the same time.
This points to the problem of having a static view of our resource consumption and production, and the paradoxical problem of having a sufficiently long time horizon. The paradox is that our technological and resource utilization mix is certain to continue changing as rapidly, if not more rapidly, than it has for the past century, yet the longer the time horizon we try to anticipate, the less certain we can be of the conditions and challenges facing our successors. Put more plainly, it is impossible for our generation to know what resources future generations will need, and in what proportions.
A resource planner in 1900 who worried about the resource needs of the year 2000 would have been taking care to secure supplies of kerosene and firewood for heating and lighting, copper for telegraph wires, rock salt for refrigeration, horses for transportation, and large amounts of land to grow feed stock for draft animals. Certainly this planner would not have known to secure large supplies of oil and gas, as they were only starting to come into major use and their supplies were abundant.
It is possible to conceive generally of technological advances in the next 75 years that will make today's resource concerns as obsolete as a concern for rock salt would have been 75 years ago. In arguing in favor of a "promethean environmentalism," Duke University Professor Martin Lewis points to the prospect of "molecular nanotechnology," i.e., programmable molecules, which would be a green technology that might even provide the means of species restoration (shades of Jurassic Park?).58
Such "out-there" ideas may seem as unthinkable today as trips to the moon 100 years ago, or the desktop personal computer 50 years ago, yet these precedents show how the unimaginable becomes the routine. And even well beneath these high-technology frontiers, it is possible to imagine such low-tech practices as mining old landfills for their raw materials, which might be thought of as retroactive recycling.59 These examples are intended to reintroduce the old economic principle of substitution to our thinking about sustainability.
In the classic Economics 101 sense of the term, new materials or methods are substituted when a resource becomes too scarce, and hence expensive. In the environmental arena it has a wider application: we can see a history of resource substitution that is both more efficient and cleaner. Some uses of non-renewable energy, especially oil and gas, are positively "green" technologies compared with the modes of energy use they replaced. For example, the development of the automobile, which is often portrayed as environmental public enemy number one, had several positive environmental tradeoffs.
First, a large amount of land previously devoted to raising feed for draft animalsas much as 25 percent of total agricultural land at the turn of the century was returned to nature or put to other, higher agricultural uses. Second, the elimination of the use of horses and other draft animals in urban settings obviously led to reduced water pollution and soil degradation, as well as improvements in urban sanitation. There were about 1.4 million horse-drawn transportation vehicles in the United States in 1900. The transport capacity of horses was three-quarters as great as the transport capacity of the railroads in 1900. As late as 1911, the value of horse-drawn transportation equipment produced was greater than the value of railroad equipment produced.60
The average horse consumed about 30 pounds of feed a day, or five tons a year. The amount of land used for growing feedstock for horses peaked at 93 million acres in 1915, an area roughly equivalent to all U.S. cities and suburbs today. Almost no land is used today to grow feedstock for horses (the U.S. government discontinued the data series for feedstock land in 1961, because the acreage had shrunk almost to zero), and this decline in land use to produce draft animal feed has doubtless contributed to the reforestation that has taken place in the United States61 (see Chart 30).
The air and water quality hazards from horse dung are obvious; a single horse would produce 12,000 pounds of manure and 400 gallons of urine a year, much of which fell on city streets. At the time, the state-of-the-art pollution control technology was a broom. In other words, the coming of the car, truck, and tractor has saved 90 million acres of land in the United States, a calculation that is usually left out of the environmental accounting of the internal combustion engine.
Another positive tradeoff of fossil fuel use has been the preservation of forests. In 1850, 50 percent of timber harvested in the United States was used for fuel. As late as the turn of the century, nearly 25 percent of the energy needs in the country were supplied by burning woodnearly five billion cubic feet a year. As fuel oil, natural gas, and electricity became widely adopted in the early decades of the century, the use of wood for fuel began declining rapidly, from more than five billion cubic feet in 1900 to less than 500 million cubic feet in 1970.
Although there was no national "spot" market for fuel wood like there was for other commodities in 1900, the price for construction lumber can be taken as a reasonable proxy for fuel wood. The inflation-adjusted price of lumber in 1900 was five times the price of lumber in 1970. It is worth noting in Chart 31 when the decline in wood use halts and heads back up againduring the Great Depression years, when fewer people could afford new gas and oil furnaces, and when businesses reduced spending for new capital equipment. Here is a clear example of the effect of economic growthand the lack of iton resource use and environmental quality. It is also ironic to recall that during the "energy crisis" of the 1970s one of the favored popular remedies was a return to wood stoves, which would have represented a step backward for both air quality and forest habitat.
There is an important lesson here for developing nations, where up to 80 percent of wood harvested is used for fuel. The development of fossil fuel energy could help lead to conservation of biologically valuable forestlands, and in some cases a reduction in air pollution. The development of cheap fossil fuel energy in the developing world will be the chief means of generating the surplus capital necessary to afford cleaner, higher-technology energy systems in the fullness of time.62 Demands that developing countries move directly to high-tech or "alternative" clean energy sources are not realistic.63
These resource and technological substitutions were fairly crude compared to what is conceivable today, yet they delivered large gains in environmental improvement. If the past is a prologue, we can look forward to even larger environmental gains in the twenty-first century. But the main point is this: The answer to the question of how non-renewable resources should be used today turns on whether a non-renewable resource is used in a manner that leads to a positive tradeoff of other environmental goods.
Such a tradeoff might be the more sustainable use of renewable resources, such as forests, and promote the development of permanent capital stock that will offer future generations more options and means to meet their needs. It is entirely appropriate to regard the use of non-renewable resources, especially fossil fuels, as "intermediate" modes on the way toward still more efficient and cleaner future modes, and therefore consistent with a dynamic understanding of sustainable development.
This is one reason why projections that come in the form, "There are only X years of Y resource at current usage rates," are not a very helpful or illuminating way of thinking about the issue. It is probably impossible to determine the practical optimum depletion rate for non-renewable resources. The common sense observation should be made at this point that every generation in human history has inherited more resources than the previous generation did. There is no reason to suppose that this will not continue for as far as it is possible to project. Doomsday scenarios of future scarcity and catastrophe, which have been issued regularly since the beginning of the industrial revolution, have consistently failed to come about. Hence, straight-line projections of current use trends should be viewed skeptically.
While it may be reasonable to suppose that there is an eventual limit to the process of resource substitutability and technological innovation that has constantly expanded the resource pool throughout history, there is no compelling evidence to conclude that this limit is imminent within the next few generations. At this point, the outer limit of resource creation is more a speculative than a scientific estimation. Most current non-renewable resources, including oil and gas, will last several generations even at projected rates of increased use.
In light of this understanding, energy efficiency policy goals need to be carefully assessed. Efficiency of any kind is always to be desired, but if it costs a constant $2 for every $1 of energy efficiency achieved, total resources are probably being wasted rather than conserved, and therefore the "efficiency" may not be environmentally benign. Many advocates of alternative energy argue that efficiency-forcing policies contribute to increased productivity and help create new markets. If this is true, such policies would be that economic rarity, the free lunch.
It may be true that in some cases managers lack proper information about environmental technologies that increase energy efficiency in a cost-effective way. But this would be an information problem, not a policy problem. Efficiency-forcing policies can only be justified if it can be shown economy-wide that such policies induce companies to make profitable innovations that they had somehow previously overlooked.64 Therefore, ambitious policy goals that would require unreasonable costs, or divert capital from potentially more productivity-improving investments, should be eschewed. While the wonks of the world debate this issue, the private sector is rendering the debate obsolete and irrelevant in many respects through its own practical steps.
Many resource-intensive industries are finding that it is not only possible, but profitable, to reduce material usage and pollution, and they have embarked on ambitious programs to reduce material use and pollution without the prod of legal mandates. In other words, we have reached a point at which environmental improvement in our industrial processes need no longer be regarded necessarily as a deadweight cost, as was supposed at the time of the first regulatory mandates 30 years ago. This accounts, for example, for the chemical industry's 50-percent reduction in "releases" in the Toxics Release Inventory. Some companies have set targets of as much as a 90-percent reduction in air emissions, 50-percent reduction in wastewater emissions, and 20-percent reduction in energy use per unit of production.65 The point is, when sustainable development is conceived as a technical problem rather than a global metaphysical and social problem, progress becomes both manageable and measurable.